RISC-V CPU Idle Support

From: Anup Patel <[email protected]>

We force select CPU_PM and provide asm/cpuidle.h so that we can use CPU IDLE drivers for Linux RISC-V kernel.

Signed-off-by Anup Patel <[email protected]>

Signed-off-by Anup Patel <[email protected]>

---
 arch/riscv/Kconfig                |  7 +++++++
 arch/riscv/configs/defconfig      |  1 +
 arch/riscv/configs/rv32_defconfig |  1 +
 arch/riscv/include/asm/cpuidle.h  | 24 ++++++++++++++++++++++++
 arch/riscv/kernel/process.c       |  3 ++-
 5 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 arch/riscv/include/asm/cpuidle.h

arch/riscv/Kconfig +7 -0

index 5adcbd9b5e88..76976d12b463 100644
@@ -46,6 +46,7 @@ config RISCV
        select CLONE_BACKWARDS
        select CLINT_TIMER if !MMU
        select COMMON_CLK
+       select CPU_PM if CPU_IDLE
        select EDAC_SUPPORT
        select GENERIC_ARCH_TOPOLOGY if SMP
        select GENERIC_ATOMIC64 if !64BIT

@@ -547,4 +548,10 @@ source "kernel/power/Kconfig"
 
 endmenu
 
+menu "CPU Power Management"
+
+source "drivers/cpuidle/Kconfig"
+
+endmenu
+
 source "arch/riscv/kvm/Kconfig"

arch/riscv/configs/defconfig +1 -0

index f120fcc43d0a..a5e0482a4969 100644
@@ -20,6 +20,7 @@ CONFIG_SOC_SIFIVE=y
 CONFIG_SOC_VIRT=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m
 CONFIG_JUMP_LABEL=y

arch/riscv/configs/rv32_defconfig +1 -0

index 8b56a7f1eb06..d1b87db54d68 100644
@@ -20,6 +20,7 @@ CONFIG_SOC_VIRT=y
 CONFIG_ARCH_RV32I=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m
 CONFIG_JUMP_LABEL=y

arch/riscv/include/asm/cpuidle.h new file +10 -0

new file mode 100644
index 000000000000..71fdc607d4bc
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2021 Allwinner Ltd
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ */
+
+#ifndef _ASM_RISCV_CPUIDLE_H
+#define _ASM_RISCV_CPUIDLE_H
+
+#include <asm/barrier.h>

arch/riscv/include/asm/cpuidle.h new file +4 -0

+       wait_for_interrupt();
+}
+
+#endif

arch/riscv/kernel/process.c +1 -0

index 03ac3aa611f5..504b496787aa 100644
@@ -23,6 +23,7 @@
 #include <asm/string.h>
 #include <asm/switch_to.h>
 #include <asm/thread_info.h>
+#include <asm/cpuidle.h>
 
 register unsigned long gp_in_global __asm__("gp");
 

arch/riscv/kernel/process.c +1 -1

-       wait_for_interrupt();
+       cpu_do_idle();
 
 
        raw_local_irq_enable();

}

--
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Reviewed-by Guo Ren <[email protected]>

small questions:

Quoted 83 lines · Anup Patel

From: Anup Patel <[email protected]>

We force select CPU_PM and provide asm/cpuidle.h so that we can use CPU IDLE drivers for Linux RISC-V kernel.

Signed-off-by Anup Patel <[email protected]>

Signed-off-by Anup Patel <[email protected]>

---
 arch/riscv/Kconfig                |  7 +++++++
 arch/riscv/configs/defconfig      |  1 +
 arch/riscv/configs/rv32_defconfig |  1 +
 arch/riscv/include/asm/cpuidle.h  | 24 ++++++++++++++++++++++++
 arch/riscv/kernel/process.c       |  3 ++-
 5 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 arch/riscv/include/asm/cpuidle.h

arch/riscv/Kconfig +7 -0

index 5adcbd9b5e88..76976d12b463 100644
@@ -46,6 +46,7 @@ config RISCV
        select CLONE_BACKWARDS
        select CLINT_TIMER if !MMU
        select COMMON_CLK
+       select CPU_PM if CPU_IDLE
        select EDAC_SUPPORT
        select GENERIC_ARCH_TOPOLOGY if SMP
        select GENERIC_ATOMIC64 if !64BIT

@@ -547,4 +548,10 @@ source "kernel/power/Kconfig"
 
 endmenu
 
+menu "CPU Power Management"
+
+source "drivers/cpuidle/Kconfig"
+
+endmenu
+
 source "arch/riscv/kvm/Kconfig"

arch/riscv/configs/defconfig +1 -0

index f120fcc43d0a..a5e0482a4969 100644
@@ -20,6 +20,7 @@ CONFIG_SOC_SIFIVE=y
 CONFIG_SOC_VIRT=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m
 CONFIG_JUMP_LABEL=y

arch/riscv/configs/rv32_defconfig +1 -0

index 8b56a7f1eb06..d1b87db54d68 100644
@@ -20,6 +20,7 @@ CONFIG_SOC_VIRT=y
 CONFIG_ARCH_RV32I=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m
 CONFIG_JUMP_LABEL=y

arch/riscv/include/asm/cpuidle.h new file +13 -0

new file mode 100644
index 000000000000..71fdc607d4bc
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2021 Allwinner Ltd
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ */
+
+#ifndef _ASM_RISCV_CPUIDLE_H
+#define _ASM_RISCV_CPUIDLE_H
+
+#include <asm/barrier.h>
+#include <asm/processor.h>
+
+static inline void cpu_do_idle(void)

arch/riscv/include/asm/cpuidle.h line 20

Quoted 7 lines

arch/riscv/include/asm/cpuidle.h new file +7 -0

+{
+       /*
+        * Add mb() here to ensure that all
+        * IO/MEM accesses are completed prior
+        * to entering WFI.
+        */
+       mb();

I think it's a separate fixup.

Quoted 18 lines

arch/riscv/include/asm/cpuidle.h new file +4 -0

+       wait_for_interrupt();
+}
+
+#endif

arch/riscv/kernel/process.c +1 -0

index 03ac3aa611f5..504b496787aa 100644
@@ -23,6 +23,7 @@
 #include <asm/string.h>
 #include <asm/switch_to.h>
 #include <asm/thread_info.h>
+#include <asm/cpuidle.h>
 
 register unsigned long gp_in_global __asm__("gp");
 

arch/riscv/kernel/process.c extern asmlinkage void ret_from_kernel_thread(void); · line 40

Quoted 3 lines

arch/riscv/kernel/process.c +0 -0

@@ -37,7 +38,7 @@ extern asmlinkage void ret_from_kernel_thread(void);
 
 void arch_cpu_idle(void)
 {

maybe below is enough.

+ mb();
   wait_for_interrupt();

Quoted 7 lines

arch/riscv/kernel/process.c +1 -1

-       wait_for_interrupt();
+       cpu_do_idle();
 
 
        raw_local_irq_enable();

}

Quoted 8 lines

--
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--
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Guo Ren

ML: https://lore.kernel.org/linux-csky/

Quoted 89 lines · Guo Ren

Reviewed-by Guo Ren <[email protected]>

small questions:

Quoted 83 lines · Anup Patel

From: Anup Patel <[email protected]>

We force select CPU_PM and provide asm/cpuidle.h so that we can use CPU IDLE drivers for Linux RISC-V kernel.

Signed-off-by Anup Patel <[email protected]>

Signed-off-by Anup Patel <[email protected]>

---
 arch/riscv/Kconfig                |  7 +++++++
 arch/riscv/configs/defconfig      |  1 +
 arch/riscv/configs/rv32_defconfig |  1 +
 arch/riscv/include/asm/cpuidle.h  | 24 ++++++++++++++++++++++++
 arch/riscv/kernel/process.c       |  3 ++-
 5 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 arch/riscv/include/asm/cpuidle.h

arch/riscv/Kconfig +7 -0

index 5adcbd9b5e88..76976d12b463 100644
@@ -46,6 +46,7 @@ config RISCV
        select CLONE_BACKWARDS
        select CLINT_TIMER if !MMU
        select COMMON_CLK
+       select CPU_PM if CPU_IDLE
        select EDAC_SUPPORT
        select GENERIC_ARCH_TOPOLOGY if SMP
        select GENERIC_ATOMIC64 if !64BIT

@@ -547,4 +548,10 @@ source "kernel/power/Kconfig"
 
 endmenu
 
+menu "CPU Power Management"
+
+source "drivers/cpuidle/Kconfig"
+
+endmenu
+
 source "arch/riscv/kvm/Kconfig"

arch/riscv/configs/defconfig +1 -0

index f120fcc43d0a..a5e0482a4969 100644
@@ -20,6 +20,7 @@ CONFIG_SOC_SIFIVE=y
 CONFIG_SOC_VIRT=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m
 CONFIG_JUMP_LABEL=y

arch/riscv/configs/rv32_defconfig +1 -0

index 8b56a7f1eb06..d1b87db54d68 100644
@@ -20,6 +20,7 @@ CONFIG_SOC_VIRT=y
 CONFIG_ARCH_RV32I=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m
 CONFIG_JUMP_LABEL=y

arch/riscv/include/asm/cpuidle.h new file +13 -0

new file mode 100644
index 000000000000..71fdc607d4bc
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2021 Allwinner Ltd
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ */
+
+#ifndef _ASM_RISCV_CPUIDLE_H
+#define _ASM_RISCV_CPUIDLE_H
+
+#include <asm/barrier.h>
+#include <asm/processor.h>
+
+static inline void cpu_do_idle(void)

Quoted 8 lines

arch/riscv/include/asm/cpuidle.h line 20

Quoted 7 lines

arch/riscv/include/asm/cpuidle.h new file +7 -0

+{
+       /*
+        * Add mb() here to ensure that all
+        * IO/MEM accesses are completed prior
+        * to entering WFI.
+        */
+       mb();

I think it's a separate fixup.

This one is tricky to move as separate fixup because there is no cpu_do_idle() until this patch adds it.

If we deliberately have a separate patch for "mb()" then it will be only fixing cpu_do_idle() function added by previous patch in the same series.

Regards,
Anup

Quoted 48 lines

Quoted 18 lines

arch/riscv/include/asm/cpuidle.h new file +4 -0

+       wait_for_interrupt();
+}
+
+#endif

arch/riscv/kernel/process.c +1 -0

index 03ac3aa611f5..504b496787aa 100644
@@ -23,6 +23,7 @@
 #include <asm/string.h>
 #include <asm/switch_to.h>
 #include <asm/thread_info.h>
+#include <asm/cpuidle.h>
 
 register unsigned long gp_in_global __asm__("gp");
 

arch/riscv/kernel/process.c extern asmlinkage void ret_from_kernel_thread(void); · line 40

Quoted 3 lines

arch/riscv/kernel/process.c +0 -0

@@ -37,7 +38,7 @@ extern asmlinkage void ret_from_kernel_thread(void);
 
 void arch_cpu_idle(void)
 {

maybe below is enough.

+ mb();
   wait_for_interrupt();

Quoted 7 lines

arch/riscv/kernel/process.c +1 -1

-       wait_for_interrupt();
+       cpu_do_idle();
 
 
        raw_local_irq_enable();

}

Quoted 8 lines

--
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--
Best Regards
Guo Ren

ML: https://lore.kernel.org/linux-csky/

Reviewed-by Guo Ren <[email protected]>

small questions:

Quoted 80 lines · Anup Patel

From: Anup Patel <[email protected]>

We force select CPU_PM and provide asm/cpuidle.h so that we can use CPU IDLE drivers for Linux RISC-V kernel.

Signed-off-by Anup Patel <[email protected]>

Signed-off-by Anup Patel <[email protected]>

---
 arch/riscv/Kconfig                |  7 +++++++
 arch/riscv/configs/defconfig      |  1 +
 arch/riscv/configs/rv32_defconfig |  1 +
 arch/riscv/include/asm/cpuidle.h  | 24 ++++++++++++++++++++++++
 arch/riscv/kernel/process.c       |  3 ++-
 5 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 arch/riscv/include/asm/cpuidle.h

arch/riscv/Kconfig +7 -0

index 5adcbd9b5e88..76976d12b463 100644
@@ -46,6 +46,7 @@ config RISCV
        select CLONE_BACKWARDS
        select CLINT_TIMER if !MMU
        select COMMON_CLK
+       select CPU_PM if CPU_IDLE
        select EDAC_SUPPORT
        select GENERIC_ARCH_TOPOLOGY if SMP
        select GENERIC_ATOMIC64 if !64BIT

@@ -547,4 +548,10 @@ source "kernel/power/Kconfig"
 
 endmenu
 
+menu "CPU Power Management"
+
+source "drivers/cpuidle/Kconfig"
+
+endmenu
+
 source "arch/riscv/kvm/Kconfig"

arch/riscv/configs/defconfig +1 -0

index f120fcc43d0a..a5e0482a4969 100644
@@ -20,6 +20,7 @@ CONFIG_SOC_SIFIVE=y
 CONFIG_SOC_VIRT=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m
 CONFIG_JUMP_LABEL=y

arch/riscv/configs/rv32_defconfig +1 -0

index 8b56a7f1eb06..d1b87db54d68 100644
@@ -20,6 +20,7 @@ CONFIG_SOC_VIRT=y
 CONFIG_ARCH_RV32I=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m
 CONFIG_JUMP_LABEL=y

arch/riscv/include/asm/cpuidle.h new file +10 -0

new file mode 100644
index 000000000000..71fdc607d4bc
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2021 Allwinner Ltd
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ */
+
+#ifndef _ASM_RISCV_CPUIDLE_H
+#define _ASM_RISCV_CPUIDLE_H
+
+#include <asm/barrier.h>

arch/riscv/include/asm/cpuidle.h line 20

Quoted 10 lines

arch/riscv/include/asm/cpuidle.h new file +10 -0

+#include <asm/processor.h>
+
+static inline void cpu_do_idle(void)
+{
+       /*
+        * Add mb() here to ensure that all
+        * IO/MEM accesses are completed prior
+        * to entering WFI.
+        */
+       mb();

I think it's a separate fixup.

Quoted 14 lines

arch/riscv/include/asm/cpuidle.h new file +4 -0

+       wait_for_interrupt();
+}
+
+#endif

arch/riscv/kernel/process.c +1 -0

index 03ac3aa611f5..504b496787aa 100644
@@ -23,6 +23,7 @@
 #include <asm/string.h>
 #include <asm/switch_to.h>
 #include <asm/thread_info.h>
+#include <asm/cpuidle.h>
 

arch/riscv/kernel/process.c extern asmlinkage void ret_from_kernel_thread(void); · line 40

Quoted 6 lines

arch/riscv/kernel/process.c +0 -0

 register unsigned long gp_in_global __asm__("gp");
 

@@ -37,7 +38,7 @@ extern asmlinkage void ret_from_kernel_thread(void);
 
 void arch_cpu_idle(void)
 {

maybe below is enough.
+ mb();

   wait_for_interrupt();

Quoted 7 lines

arch/riscv/kernel/process.c +1 -1

-       wait_for_interrupt();
+       cpu_do_idle();
 
 
        raw_local_irq_enable();

}

Quoted 8 lines

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Guo Ren

ML: https://lore.kernel.org/linux-csky/

From: Anup Patel <[email protected]>

The low-level relocate() function enables mmu and relocates execution to link-time addresses. We rename relocate() function to relocate_enable_mmu() function which is more informative.

Also, the relocate_enable_mmu() function will be used in the resume path when a CPU wakes-up from a non-retentive suspend so we make it global symbol.

Signed-off-by Anup Patel <[email protected]>

Signed-off-by Anup Patel <[email protected]>

---
 arch/riscv/kernel/head.S | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

arch/riscv/kernel/head.S +4 -4

index 2363b43312fc..5f4c6b6c4974 100644
@@ -90,7 +90,8 @@ pe_head_start:
 
 .align 2
 #ifdef CONFIG_MMU
-relocate:
+       .global relocate_enable_mmu
+relocate_enable_mmu:
        /* Relocate return address */
        la a1, kernel_map
        XIP_FIXUP_OFFSET a1

@@ -185,7 +186,7 @@ secondary_start_sbi:
        /* Enable virtual memory and relocate to virtual address */
        la a0, swapper_pg_dir
        XIP_FIXUP_OFFSET a0
-       call relocate
+       call relocate_enable_mmu
 #endif
        call setup_trap_vector
        tail smp_callin

@@ -329,7 +330,7 @@ clear_bss_done:
 #ifdef CONFIG_MMU
        la a0, early_pg_dir
        XIP_FIXUP_OFFSET a0
-       call relocate
+       call relocate_enable_mmu
 #endif /* CONFIG_MMU */
 
        call setup_trap_vector
--

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From: Anup Patel <[email protected]>

The hart registers and CSRs are not preserved in non-retentative suspend state so we provide arch specific helper functions which will save/restore hart context upon entry/exit to non-retentive suspend state. These helper functions can be used by cpuidle drivers for non-retentive suspend entry/exit.

Signed-off-by Anup Patel <[email protected]>

Signed-off-by Anup Patel <[email protected]>

---
 arch/riscv/include/asm/asm.h      |  27 +++++++
 arch/riscv/include/asm/suspend.h  |  36 +++++++++
 arch/riscv/kernel/Makefile        |   2 +
 arch/riscv/kernel/asm-offsets.c   |   3 +
 arch/riscv/kernel/head.S          |  21 -----
 arch/riscv/kernel/suspend.c       |  87 +++++++++++++++++++++
 arch/riscv/kernel/suspend_entry.S | 124 ++++++++++++++++++++++++++++++
 7 files changed, 279 insertions(+), 21 deletions(-)
 create mode 100644 arch/riscv/include/asm/suspend.h
 create mode 100644 arch/riscv/kernel/suspend.c
 create mode 100644 arch/riscv/kernel/suspend_entry.S

arch/riscv/include/asm/asm.h +27 -0

index 618d7c5af1a2..48b4baa4d706 100644
@@ -67,4 +67,31 @@
 #error "Unexpected __SIZEOF_SHORT__"
 #endif
 
+#ifdef __ASSEMBLY__
+
+/* Common assembly source macros */
+
+#ifdef CONFIG_XIP_KERNEL
+.macro XIP_FIXUP_OFFSET reg
+       REG_L t0, _xip_fixup
+       add \reg, \reg, t0
+.endm
+.macro XIP_FIXUP_FLASH_OFFSET reg
+       la t1, __data_loc
+       li t0, XIP_OFFSET_MASK
+       and t1, t1, t0
+       li t1, XIP_OFFSET
+       sub t0, t0, t1
+       sub \reg, \reg, t0
+.endm
+_xip_fixup: .dword CONFIG_PHYS_RAM_BASE - CONFIG_XIP_PHYS_ADDR - XIP_OFFSET
+#else
+.macro XIP_FIXUP_OFFSET reg
+.endm
+.macro XIP_FIXUP_FLASH_OFFSET reg
+.endm
+#endif /* CONFIG_XIP_KERNEL */
+
+#endif /* __ASSEMBLY__ */
+
 #endif /* _ASM_RISCV_ASM_H */

arch/riscv/include/asm/suspend.h new file +36 -0

new file mode 100644
index 000000000000..8be391c2aecb
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2021 Western Digital Corporation or its affiliates.
+ * Copyright (c) 2022 Ventana Micro Systems Inc.
+ */
+
+#ifndef _ASM_RISCV_SUSPEND_H
+#define _ASM_RISCV_SUSPEND_H
+
+#include <asm/ptrace.h>
+
+struct suspend_context {
+       /* Saved and restored by low-level functions */
+       struct pt_regs regs;
+       /* Saved and restored by high-level functions */
+       unsigned long scratch;
+       unsigned long tvec;
+       unsigned long ie;
+#ifdef CONFIG_MMU
+       unsigned long satp;
+#endif
+};
+
+/* Low-level CPU suspend entry function */
+int __cpu_suspend_enter(struct suspend_context *context);
+
+/* High-level CPU suspend which will save context and call finish() */
+int cpu_suspend(unsigned long arg,
+               int (*finish)(unsigned long arg,
+                             unsigned long entry,
+                             unsigned long context));
+
+/* Low-level CPU resume entry function */
+int __cpu_resume_enter(unsigned long hartid, unsigned long context);
+
+#endif

arch/riscv/kernel/Makefile +2 -0

index 612556faa527..13fa5733f5e7 100644
@@ -48,6 +48,8 @@ obj-$(CONFIG_RISCV_BOOT_SPINWAIT) += cpu_ops_spinwait.o
 obj-$(CONFIG_MODULES)          += module.o
 obj-$(CONFIG_MODULE_SECTIONS)  += module-sections.o
 
+obj-$(CONFIG_CPU_PM)           += suspend_entry.o suspend.o
+
 obj-$(CONFIG_FUNCTION_TRACER)  += mcount.o ftrace.o
 obj-$(CONFIG_DYNAMIC_FTRACE)   += mcount-dyn.o
 

arch/riscv/kernel/asm-offsets.c +3 -0

index df0519a64eaf..df9444397908 100644
@@ -13,6 +13,7 @@
 #include <asm/thread_info.h>
 #include <asm/ptrace.h>
 #include <asm/cpu_ops_sbi.h>
+#include <asm/suspend.h>
 
 void asm_offsets(void);
 

@@ -113,6 +114,8 @@ void asm_offsets(void)
        OFFSET(PT_BADADDR, pt_regs, badaddr);
        OFFSET(PT_CAUSE, pt_regs, cause);
 
+       OFFSET(SUSPEND_CONTEXT_REGS, suspend_context, regs);
+
        OFFSET(KVM_ARCH_GUEST_ZERO, kvm_vcpu_arch, guest_context.zero);
        OFFSET(KVM_ARCH_GUEST_RA, kvm_vcpu_arch, guest_context.ra);
        OFFSET(KVM_ARCH_GUEST_SP, kvm_vcpu_arch, guest_context.sp);

arch/riscv/kernel/head.S +0 -21

index 5f4c6b6c4974..893b8bb69391 100644
@@ -16,27 +16,6 @@
 #include <asm/image.h>
 #include "efi-header.S"
 
-#ifdef CONFIG_XIP_KERNEL
-.macro XIP_FIXUP_OFFSET reg
-       REG_L t0, _xip_fixup
-       add \reg, \reg, t0
-.endm
-.macro XIP_FIXUP_FLASH_OFFSET reg
-       la t1, __data_loc
-       li t0, XIP_OFFSET_MASK
-       and t1, t1, t0
-       li t1, XIP_OFFSET
-       sub t0, t0, t1
-       sub \reg, \reg, t0
-.endm
-_xip_fixup: .dword CONFIG_PHYS_RAM_BASE - CONFIG_XIP_PHYS_ADDR - XIP_OFFSET
-#else
-.macro XIP_FIXUP_OFFSET reg
-.endm
-.macro XIP_FIXUP_FLASH_OFFSET reg
-.endm
-#endif /* CONFIG_XIP_KERNEL */
-
 __HEAD
 ENTRY(_start)
        /*

arch/riscv/kernel/suspend.c new file +87 -0

new file mode 100644
index 000000000000..9ba24fb8cc93
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2021 Western Digital Corporation or its affiliates.
+ * Copyright (c) 2022 Ventana Micro Systems Inc.
+ */
+
+#include <linux/ftrace.h>
+#include <asm/csr.h>
+#include <asm/suspend.h>
+
+static void suspend_save_csrs(struct suspend_context *context)
+{
+       context->scratch = csr_read(CSR_SCRATCH);
+       context->tvec = csr_read(CSR_TVEC);
+       context->ie = csr_read(CSR_IE);
+
+       /*
+        * No need to save/restore IP CSR (i.e. MIP or SIP) because:
+        *
+        * 1. For no-MMU (M-mode) kernel, the bits in MIP are set by
+        *    external devices (such as interrupt controller, timer, etc).
+        * 2. For MMU (S-mode) kernel, the bits in SIP are set by
+        *    M-mode firmware and external devices (such as interrupt
+        *    controller, etc).
+        */
+
+#ifdef CONFIG_MMU
+       context->satp = csr_read(CSR_SATP);
+#endif
+}
+
+static void suspend_restore_csrs(struct suspend_context *context)
+{
+       csr_write(CSR_SCRATCH, context->scratch);
+       csr_write(CSR_TVEC, context->tvec);
+       csr_write(CSR_IE, context->ie);
+
+#ifdef CONFIG_MMU
+       csr_write(CSR_SATP, context->satp);
+#endif
+}
+
+int cpu_suspend(unsigned long arg,
+               int (*finish)(unsigned long arg,
+                             unsigned long entry,
+                             unsigned long context))
+{
+       int rc = 0;
+       struct suspend_context context = { 0 };
+
+       /* Finisher should be non-NULL */
+       if (!finish)
+               return -EINVAL;
+
+       /* Save additional CSRs*/
+       suspend_save_csrs(&context);
+
+       /*
+        * Function graph tracer state gets incosistent when the kernel
+        * calls functions that never return (aka finishers) hence disable
+        * graph tracing during their execution.
+        */
+       pause_graph_tracing();
+
+       /* Save context on stack */
+       if (__cpu_suspend_enter(&context)) {
+               /* Call the finisher */
+               rc = finish(arg, __pa_symbol(__cpu_resume_enter),
+                           (ulong)&context);
+
+               /*
+                * Should never reach here, unless the suspend finisher
+                * fails. Successful cpu_suspend() should return from
+                * __cpu_resume_entry()
+                */
+               if (!rc)
+                       rc = -EOPNOTSUPP;
+       }
+
+       /* Enable function graph tracer */
+       unpause_graph_tracing();
+
+       /* Restore additional CSRs */
+       suspend_restore_csrs(&context);
+
+       return rc;
+}

arch/riscv/kernel/suspend_entry.S new file +124 -1

new file mode 100644
index 000000000000..4b07b809a2b8
@@ -0,0 +1,124 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2021 Western Digital Corporation or its affiliates.
+ * Copyright (c) 2022 Ventana Micro Systems Inc.
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/csr.h>
+
+       .text
+       .altmacro
+       .option norelax
+
+ENTRY(__cpu_suspend_enter)
+       /* Save registers (except A0 and T0-T6) */
+       REG_S   ra, (SUSPEND_CONTEXT_REGS + PT_RA)(a0)
+       REG_S   sp, (SUSPEND_CONTEXT_REGS + PT_SP)(a0)
+       REG_S   gp, (SUSPEND_CONTEXT_REGS + PT_GP)(a0)
+       REG_S   tp, (SUSPEND_CONTEXT_REGS + PT_TP)(a0)
+       REG_S   s0, (SUSPEND_CONTEXT_REGS + PT_S0)(a0)
+       REG_S   s1, (SUSPEND_CONTEXT_REGS + PT_S1)(a0)
+       REG_S   a1, (SUSPEND_CONTEXT_REGS + PT_A1)(a0)
+       REG_S   a2, (SUSPEND_CONTEXT_REGS + PT_A2)(a0)
+       REG_S   a3, (SUSPEND_CONTEXT_REGS + PT_A3)(a0)
+       REG_S   a4, (SUSPEND_CONTEXT_REGS + PT_A4)(a0)
+       REG_S   a5, (SUSPEND_CONTEXT_REGS + PT_A5)(a0)
+       REG_S   a6, (SUSPEND_CONTEXT_REGS + PT_A6)(a0)
+       REG_S   a7, (SUSPEND_CONTEXT_REGS + PT_A7)(a0)
+       REG_S   s2, (SUSPEND_CONTEXT_REGS + PT_S2)(a0)
+       REG_S   s3, (SUSPEND_CONTEXT_REGS + PT_S3)(a0)
+       REG_S   s4, (SUSPEND_CONTEXT_REGS + PT_S4)(a0)
+       REG_S   s5, (SUSPEND_CONTEXT_REGS + PT_S5)(a0)
+       REG_S   s6, (SUSPEND_CONTEXT_REGS + PT_S6)(a0)
+       REG_S   s7, (SUSPEND_CONTEXT_REGS + PT_S7)(a0)
+       REG_S   s8, (SUSPEND_CONTEXT_REGS + PT_S8)(a0)
+       REG_S   s9, (SUSPEND_CONTEXT_REGS + PT_S9)(a0)
+       REG_S   s10, (SUSPEND_CONTEXT_REGS + PT_S10)(a0)
+       REG_S   s11, (SUSPEND_CONTEXT_REGS + PT_S11)(a0)
+
+       /* Save CSRs */
+       csrr    t0, CSR_EPC
+       REG_S   t0, (SUSPEND_CONTEXT_REGS + PT_EPC)(a0)
+       csrr    t0, CSR_STATUS
+       REG_S   t0, (SUSPEND_CONTEXT_REGS + PT_STATUS)(a0)
+       csrr    t0, CSR_TVAL
+       REG_S   t0, (SUSPEND_CONTEXT_REGS + PT_BADADDR)(a0)
+       csrr    t0, CSR_CAUSE
+       REG_S   t0, (SUSPEND_CONTEXT_REGS + PT_CAUSE)(a0)
+
+       /* Return non-zero value */
+       li      a0, 1
+
+       /* Return to C code */
+       ret
+END(__cpu_suspend_enter)
+
+ENTRY(__cpu_resume_enter)
+       /* Load the global pointer */
+       .option push
+       .option norelax
+               la gp, __global_pointer$
+       .option pop
+
+#ifdef CONFIG_MMU
+       /* Save A0 and A1 */
+       add     t0, a0, zero
+       add     t1, a1, zero
+
+       /* Enable MMU */
+       la      a0, swapper_pg_dir
+       XIP_FIXUP_OFFSET a0
+       call    relocate_enable_mmu
+
+       /* Restore A0 and A1 */
+       add     a0, t0, zero
+       add     a1, t1, zero
+#endif
+
+       /* Make A0 point to suspend context */
+       add     a0, a1, zero
+
+       /* Restore CSRs */
+       REG_L   t0, (SUSPEND_CONTEXT_REGS + PT_EPC)(a0)
+       csrw    CSR_EPC, t0
+       REG_L   t0, (SUSPEND_CONTEXT_REGS + PT_STATUS)(a0)
+       csrw    CSR_STATUS, t0
+       REG_L   t0, (SUSPEND_CONTEXT_REGS + PT_BADADDR)(a0)
+       csrw    CSR_TVAL, t0
+       REG_L   t0, (SUSPEND_CONTEXT_REGS + PT_CAUSE)(a0)
+       csrw    CSR_CAUSE, t0
+
+       /* Restore registers (except A0 and T0-T6) */
+       REG_L   ra, (SUSPEND_CONTEXT_REGS + PT_RA)(a0)
+       REG_L   sp, (SUSPEND_CONTEXT_REGS + PT_SP)(a0)
+       REG_L   gp, (SUSPEND_CONTEXT_REGS + PT_GP)(a0)
+       REG_L   tp, (SUSPEND_CONTEXT_REGS + PT_TP)(a0)
+       REG_L   s0, (SUSPEND_CONTEXT_REGS + PT_S0)(a0)
+       REG_L   s1, (SUSPEND_CONTEXT_REGS + PT_S1)(a0)
+       REG_L   a1, (SUSPEND_CONTEXT_REGS + PT_A1)(a0)
+       REG_L   a2, (SUSPEND_CONTEXT_REGS + PT_A2)(a0)
+       REG_L   a3, (SUSPEND_CONTEXT_REGS + PT_A3)(a0)
+       REG_L   a4, (SUSPEND_CONTEXT_REGS + PT_A4)(a0)
+       REG_L   a5, (SUSPEND_CONTEXT_REGS + PT_A5)(a0)
+       REG_L   a6, (SUSPEND_CONTEXT_REGS + PT_A6)(a0)
+       REG_L   a7, (SUSPEND_CONTEXT_REGS + PT_A7)(a0)
+       REG_L   s2, (SUSPEND_CONTEXT_REGS + PT_S2)(a0)
+       REG_L   s3, (SUSPEND_CONTEXT_REGS + PT_S3)(a0)
+       REG_L   s4, (SUSPEND_CONTEXT_REGS + PT_S4)(a0)
+       REG_L   s5, (SUSPEND_CONTEXT_REGS + PT_S5)(a0)
+       REG_L   s6, (SUSPEND_CONTEXT_REGS + PT_S6)(a0)
+       REG_L   s7, (SUSPEND_CONTEXT_REGS + PT_S7)(a0)
+       REG_L   s8, (SUSPEND_CONTEXT_REGS + PT_S8)(a0)
+       REG_L   s9, (SUSPEND_CONTEXT_REGS + PT_S9)(a0)
+       REG_L   s10, (SUSPEND_CONTEXT_REGS + PT_S10)(a0)
+       REG_L   s11, (SUSPEND_CONTEXT_REGS + PT_S11)(a0)
+
+       /* Return zero value */
+       add     a0, zero, zero
+
+       /* Return to C code */
+       ret
+END(__cpu_resume_enter)
--

2.25.1

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From: Anup Patel <[email protected]>

We add defines related to SBI HSM suspend call and also update HSM states naming as-per latest SBI specification.

Signed-off-by Anup Patel <[email protected]>

Signed-off-by Anup Patel <[email protected]>

---
 arch/riscv/include/asm/sbi.h    | 27 ++++++++++++++++++++++-----
 arch/riscv/kernel/cpu_ops_sbi.c |  2 +-
 arch/riscv/kvm/vcpu_sbi_hsm.c   |  4 ++--
 3 files changed, 25 insertions(+), 8 deletions(-)

arch/riscv/include/asm/sbi.h +22 -5

index d1c37479d828..06133b4f8e20 100644
@@ -71,15 +71,32 @@ enum sbi_ext_hsm_fid {
        SBI_EXT_HSM_HART_START = 0,
        SBI_EXT_HSM_HART_STOP,
        SBI_EXT_HSM_HART_STATUS,
+       SBI_EXT_HSM_HART_SUSPEND,
 };
 
-enum sbi_hsm_hart_status {
-       SBI_HSM_HART_STATUS_STARTED = 0,
-       SBI_HSM_HART_STATUS_STOPPED,
-       SBI_HSM_HART_STATUS_START_PENDING,
-       SBI_HSM_HART_STATUS_STOP_PENDING,
+enum sbi_hsm_hart_state {
+       SBI_HSM_STATE_STARTED = 0,
+       SBI_HSM_STATE_STOPPED,
+       SBI_HSM_STATE_START_PENDING,
+       SBI_HSM_STATE_STOP_PENDING,
+       SBI_HSM_STATE_SUSPENDED,
+       SBI_HSM_STATE_SUSPEND_PENDING,
+       SBI_HSM_STATE_RESUME_PENDING,
 };
 
+#define SBI_HSM_SUSP_BASE_MASK                 0x7fffffff
+#define SBI_HSM_SUSP_NON_RET_BIT               0x80000000
+#define SBI_HSM_SUSP_PLAT_BASE                 0x10000000
+
+#define SBI_HSM_SUSPEND_RET_DEFAULT            0x00000000
+#define SBI_HSM_SUSPEND_RET_PLATFORM           SBI_HSM_SUSP_PLAT_BASE
+#define SBI_HSM_SUSPEND_RET_LAST               SBI_HSM_SUSP_BASE_MASK
+#define SBI_HSM_SUSPEND_NON_RET_DEFAULT                SBI_HSM_SUSP_NON_RET_BIT
+#define SBI_HSM_SUSPEND_NON_RET_PLATFORM       (SBI_HSM_SUSP_NON_RET_BIT | \
+                                                SBI_HSM_SUSP_PLAT_BASE)
+#define SBI_HSM_SUSPEND_NON_RET_LAST           (SBI_HSM_SUSP_NON_RET_BIT | \
+                                                SBI_HSM_SUSP_BASE_MASK)
+
 enum sbi_ext_srst_fid {
        SBI_EXT_SRST_RESET = 0,
 };

arch/riscv/kernel/cpu_ops_sbi.c +1 -1

index dae29cbfe550..2e16f6732cdf 100644
@@ -111,7 +111,7 @@ static int sbi_cpu_is_stopped(unsigned int cpuid)
 
        rc = sbi_hsm_hart_get_status(hartid);
 
-       if (rc == SBI_HSM_HART_STATUS_STOPPED)
+       if (rc == SBI_HSM_STATE_STOPPED)
                return 0;
        return rc;
 }

arch/riscv/kvm/vcpu_sbi_hsm.c +2 -3

index 2e383687fa48..1ac4b2e8e4ec 100644
@@ -60,9 +60,9 @@ static int kvm_sbi_hsm_vcpu_get_status(struct kvm_vcpu *vcpu)
        if (!target_vcpu)
                return -EINVAL;
        if (!target_vcpu->arch.power_off)
-               return SBI_HSM_HART_STATUS_STARTED;
+               return SBI_HSM_STATE_STARTED;
        else
-               return SBI_HSM_HART_STATUS_STOPPED;
+               return SBI_HSM_STATE_STOPPED;
 }
 
 static int kvm_sbi_ext_hsm_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
--

2.25.1

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From: Anup Patel <[email protected]>

The RISC-V SBI HSM extension provides HSM suspend call which can be used by Linux RISC-V to enter platform specific low-power state.

This patch adds a CPU idle driver based on RISC-V SBI calls which will populate idle states from device tree and use SBI calls to entry these idle states.

Signed-off-by Anup Patel <[email protected]>

Reviewed-by Anup Patel <[email protected]>

---
 MAINTAINERS                         |   7 +
 drivers/cpuidle/Kconfig             |   5 +
 drivers/cpuidle/Kconfig.riscv       |  15 +
 drivers/cpuidle/Makefile            |   4 +
 drivers/cpuidle/cpuidle-riscv-sbi.c | 627 ++++++++++++++++++++++++++++
 5 files changed, 658 insertions(+)
 create mode 100644 drivers/cpuidle/Kconfig.riscv
 create mode 100644 drivers/cpuidle/cpuidle-riscv-sbi.c

MAINTAINERS +7 -0

index 0c67ebe7f07e..15c63a717458 100644
@@ -5058,6 +5058,13 @@ S:       Supported
 F:     drivers/cpuidle/dt_idle_genpd.c
 F:     drivers/cpuidle/dt_idle_genpd.h
 
+CPUIDLE DRIVER - RISC-V SBI
+M:     Anup Patel <[email protected]>
+L:     linux-pm at vger.kernel.org
+L:     linux-riscv at lists.infradead.org
+S:     Maintained
+F:     drivers/cpuidle/cpuidle-riscv-sbi.c
+
 CRAMFS FILESYSTEM
 M:     Nicolas Pitre <[email protected]>
 S:     Maintained

drivers/cpuidle/Kconfig +5 -0

index f1afe7ab6b54..ff71dd662880 100644
@@ -66,6 +66,11 @@ depends on PPC
 source "drivers/cpuidle/Kconfig.powerpc"
 endmenu
 
+menu "RISC-V CPU Idle Drivers"
+depends on RISCV
+source "drivers/cpuidle/Kconfig.riscv"
+endmenu
+
 config HALTPOLL_CPUIDLE
        tristate "Halt poll cpuidle driver"
        depends on X86 && KVM_GUEST

drivers/cpuidle/Kconfig.riscv new file +15 -0

new file mode 100644
index 000000000000..78518c26af74
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# RISC-V CPU Idle drivers
+#
+
+config RISCV_SBI_CPUIDLE
+       bool "RISC-V SBI CPU idle Driver"
+       depends on RISCV_SBI
+       select DT_IDLE_STATES
+       select CPU_IDLE_MULTIPLE_DRIVERS
+       select DT_IDLE_GENPD if PM_GENERIC_DOMAINS_OF
+       help
+         Select this option to enable RISC-V SBI firmware based CPU idle
+         driver for RISC-V systems. This drivers also supports hierarchical
+         DT based layout of the idle state.

drivers/cpuidle/Makefile +4 -0

index 11a26cef279f..d103342b7cfc 100644
@@ -35,3 +35,7 @@ obj-$(CONFIG_MIPS_CPS_CPUIDLE)                += cpuidle-cps.o
 # POWERPC drivers
 obj-$(CONFIG_PSERIES_CPUIDLE)          += cpuidle-pseries.o
 obj-$(CONFIG_POWERNV_CPUIDLE)          += cpuidle-powernv.o
+
+###############################################################################
+# RISC-V drivers
+obj-$(CONFIG_RISCV_SBI_CPUIDLE)                += cpuidle-riscv-sbi.o

drivers/cpuidle/cpuidle-riscv-sbi.c new file +627 -1

new file mode 100644
index 000000000000..b459eda2cd37
@@ -0,0 +1,627 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * RISC-V SBI CPU idle driver.
+ *
+ * Copyright (c) 2021 Western Digital Corporation or its affiliates.
+ * Copyright (c) 2022 Ventana Micro Systems Inc.
+ */
+
+#define pr_fmt(fmt) "cpuidle-riscv-sbi: " fmt
+
+#include <linux/cpuidle.h>
+#include <linux/cpumask.h>
+#include <linux/cpu_pm.h>
+#include <linux/cpu_cooling.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/pm_runtime.h>
+#include <asm/cpuidle.h>
+#include <asm/sbi.h>
+#include <asm/suspend.h>
+
+#include "dt_idle_states.h"
+#include "dt_idle_genpd.h"
+
+struct sbi_cpuidle_data {
+       u32 *states;
+       struct device *dev;
+};
+
+struct sbi_domain_state {
+       bool available;
+       u32 state;
+};
+
+static DEFINE_PER_CPU_READ_MOSTLY(struct sbi_cpuidle_data, sbi_cpuidle_data);
+static DEFINE_PER_CPU(struct sbi_domain_state, domain_state);
+static bool sbi_cpuidle_use_osi;
+static bool sbi_cpuidle_use_cpuhp;
+static bool sbi_cpuidle_pd_allow_domain_state;
+
+static inline void sbi_set_domain_state(u32 state)
+{
+       struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
+
+       data->available = true;
+       data->state = state;
+}
+
+static inline u32 sbi_get_domain_state(void)
+{
+       struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
+
+       return data->state;
+}
+
+static inline void sbi_clear_domain_state(void)
+{
+       struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
+
+       data->available = false;
+}
+
+static inline bool sbi_is_domain_state_available(void)
+{
+       struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
+
+       return data->available;
+}
+
+static int sbi_suspend_finisher(unsigned long suspend_type,
+                               unsigned long resume_addr,
+                               unsigned long opaque)
+{
+       struct sbiret ret;
+
+       ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_SUSPEND,
+                       suspend_type, resume_addr, opaque, 0, 0, 0);
+
+       return (ret.error) ? sbi_err_map_linux_errno(ret.error) : 0;
+}
+
+static int sbi_suspend(u32 state)
+{
+       if (state & SBI_HSM_SUSP_NON_RET_BIT)
+               return cpu_suspend(state, sbi_suspend_finisher);
+       else
+               return sbi_suspend_finisher(state, 0, 0);
+}
+
+static int sbi_cpuidle_enter_state(struct cpuidle_device *dev,
+                                  struct cpuidle_driver *drv, int idx)
+{
+       u32 *states = __this_cpu_read(sbi_cpuidle_data.states);
+
+       return CPU_PM_CPU_IDLE_ENTER_PARAM(sbi_suspend, idx, states[idx]);
+}
+
+static int __sbi_enter_domain_idle_state(struct cpuidle_device *dev,
+                                         struct cpuidle_driver *drv, int idx,
+                                         bool s2idle)
+{
+       struct sbi_cpuidle_data *data = this_cpu_ptr(&sbi_cpuidle_data);
+       u32 *states = data->states;
+       struct device *pd_dev = data->dev;
+       u32 state;
+       int ret;
+
+       ret = cpu_pm_enter();
+       if (ret)
+               return -1;
+
+       /* Do runtime PM to manage a hierarchical CPU toplogy. */
+       rcu_irq_enter_irqson();
+       if (s2idle)
+               dev_pm_genpd_suspend(pd_dev);
+       else
+               pm_runtime_put_sync_suspend(pd_dev);
+       rcu_irq_exit_irqson();
+
+       if (sbi_is_domain_state_available())
+               state = sbi_get_domain_state();
+       else
+               state = states[idx];
+
+       ret = sbi_suspend(state) ? -1 : idx;
+
+       rcu_irq_enter_irqson();
+       if (s2idle)
+               dev_pm_genpd_resume(pd_dev);
+       else
+               pm_runtime_get_sync(pd_dev);
+       rcu_irq_exit_irqson();
+
+       cpu_pm_exit();
+
+       /* Clear the domain state to start fresh when back from idle. */
+       sbi_clear_domain_state();
+       return ret;
+}
+
+static int sbi_enter_domain_idle_state(struct cpuidle_device *dev,
+                                      struct cpuidle_driver *drv, int idx)
+{
+       return __sbi_enter_domain_idle_state(dev, drv, idx, false);
+}
+
+static int sbi_enter_s2idle_domain_idle_state(struct cpuidle_device *dev,
+                                             struct cpuidle_driver *drv,
+                                             int idx)
+{
+       return __sbi_enter_domain_idle_state(dev, drv, idx, true);
+}
+
+static int sbi_cpuidle_cpuhp_up(unsigned int cpu)
+{
+       struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);
+
+       if (pd_dev)
+               pm_runtime_get_sync(pd_dev);
+
+       return 0;
+}
+
+static int sbi_cpuidle_cpuhp_down(unsigned int cpu)
+{
+       struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);
+
+       if (pd_dev) {
+               pm_runtime_put_sync(pd_dev);
+               /* Clear domain state to start fresh at next online. */
+               sbi_clear_domain_state();
+       }
+
+       return 0;
+}
+
+static void sbi_idle_init_cpuhp(void)
+{
+       int err;
+
+       if (!sbi_cpuidle_use_cpuhp)
+               return;
+
+       err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,
+                                       "cpuidle/sbi:online",
+                                       sbi_cpuidle_cpuhp_up,
+                                       sbi_cpuidle_cpuhp_down);
+       if (err)
+               pr_warn("Failed %d while setup cpuhp state\n", err);
+}
+
+static const struct of_device_id sbi_cpuidle_state_match[] = {
+       { .compatible = "riscv,idle-state",
+         .data = sbi_cpuidle_enter_state },
+       { },
+};
+
+static bool sbi_suspend_state_is_valid(u32 state)
+{
+       if (state > SBI_HSM_SUSPEND_RET_DEFAULT &&
+           state < SBI_HSM_SUSPEND_RET_PLATFORM)
+               return false;
+       if (state > SBI_HSM_SUSPEND_NON_RET_DEFAULT &&
+           state < SBI_HSM_SUSPEND_NON_RET_PLATFORM)
+               return false;
+       return true;
+}
+
+static int sbi_dt_parse_state_node(struct device_node *np, u32 *state)
+{
+       int err = of_property_read_u32(np, "riscv,sbi-suspend-param", state);
+
+       if (err) {
+               pr_warn("%pOF missing riscv,sbi-suspend-param property\n", np);
+               return err;
+       }
+
+       if (!sbi_suspend_state_is_valid(*state)) {
+               pr_warn("Invalid SBI suspend state %#x\n", *state);
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+static int sbi_dt_cpu_init_topology(struct cpuidle_driver *drv,
+                                    struct sbi_cpuidle_data *data,
+                                    unsigned int state_count, int cpu)
+{
+       /* Currently limit the hierarchical topology to be used in OSI mode. */
+       if (!sbi_cpuidle_use_osi)
+               return 0;
+
+       data->dev = dt_idle_attach_cpu(cpu, "sbi");
+       if (IS_ERR_OR_NULL(data->dev))
+               return PTR_ERR_OR_ZERO(data->dev);
+
+       /*
+        * Using the deepest state for the CPU to trigger a potential selection
+        * of a shared state for the domain, assumes the domain states are all
+        * deeper states.
+        */
+       drv->states[state_count - 1].enter = sbi_enter_domain_idle_state;
+       drv->states[state_count - 1].enter_s2idle =
+                                       sbi_enter_s2idle_domain_idle_state;
+       sbi_cpuidle_use_cpuhp = true;
+
+       return 0;
+}
+
+static int sbi_cpuidle_dt_init_states(struct device *dev,
+                                       struct cpuidle_driver *drv,
+                                       unsigned int cpu,
+                                       unsigned int state_count)
+{
+       struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
+       struct device_node *state_node;
+       struct device_node *cpu_node;
+       u32 *states;
+       int i, ret;
+
+       cpu_node = of_cpu_device_node_get(cpu);
+       if (!cpu_node)
+               return -ENODEV;
+
+       states = devm_kcalloc(dev, state_count, sizeof(*states), GFP_KERNEL);
+       if (!states) {
+               ret = -ENOMEM;
+               goto fail;
+       }
+
+       /* Parse SBI specific details from state DT nodes */
+       for (i = 1; i < state_count; i++) {
+               state_node = of_get_cpu_state_node(cpu_node, i - 1);
+               if (!state_node)
+                       break;
+
+               ret = sbi_dt_parse_state_node(state_node, &states[i]);
+               of_node_put(state_node);
+
+               if (ret)
+                       return ret;
+
+               pr_debug("sbi-state %#x index %d\n", states[i], i);
+       }
+       if (i != state_count) {
+               ret = -ENODEV;
+               goto fail;
+       }
+
+       /* Initialize optional data, used for the hierarchical topology. */
+       ret = sbi_dt_cpu_init_topology(drv, data, state_count, cpu);
+       if (ret < 0)
+               return ret;
+
+       /* Store states in the per-cpu struct. */
+       data->states = states;
+
+fail:
+       of_node_put(cpu_node);
+
+       return ret;
+}
+
+static void sbi_cpuidle_deinit_cpu(int cpu)
+{
+       struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
+
+       dt_idle_detach_cpu(data->dev);
+       sbi_cpuidle_use_cpuhp = false;
+}
+
+static int sbi_cpuidle_init_cpu(struct device *dev, int cpu)
+{
+       struct cpuidle_driver *drv;
+       unsigned int state_count = 0;
+       int ret = 0;
+
+       drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
+       if (!drv)
+               return -ENOMEM;
+
+       drv->name = "sbi_cpuidle";
+       drv->owner = THIS_MODULE;
+       drv->cpumask = (struct cpumask *)cpumask_of(cpu);
+
+       /* RISC-V architectural WFI to be represented as state index 0. */
+       drv->states[0].enter = sbi_cpuidle_enter_state;
+       drv->states[0].exit_latency = 1;
+       drv->states[0].target_residency = 1;
+       drv->states[0].power_usage = UINT_MAX;
+       strcpy(drv->states[0].name, "WFI");
+       strcpy(drv->states[0].desc, "RISC-V WFI");
+
+       /*
+        * If no DT idle states are detected (ret == 0) let the driver
+        * initialization fail accordingly since there is no reason to
+        * initialize the idle driver if only wfi is supported, the
+        * default archictectural back-end already executes wfi
+        * on idle entry.
+        */
+       ret = dt_init_idle_driver(drv, sbi_cpuidle_state_match, 1);
+       if (ret <= 0) {
+               pr_debug("HART%ld: failed to parse DT idle states\n",
+                        cpuid_to_hartid_map(cpu));
+               return ret ? : -ENODEV;
+       }
+       state_count = ret + 1; /* Include WFI state as well */
+
+       /* Initialize idle states from DT. */
+       ret = sbi_cpuidle_dt_init_states(dev, drv, cpu, state_count);
+       if (ret) {
+               pr_err("HART%ld: failed to init idle states\n",
+                      cpuid_to_hartid_map(cpu));
+               return ret;
+       }
+
+       ret = cpuidle_register(drv, NULL);
+       if (ret)
+               goto deinit;
+
+       cpuidle_cooling_register(drv);
+
+       return 0;
+deinit:
+       sbi_cpuidle_deinit_cpu(cpu);
+       return ret;
+}
+
+static void sbi_cpuidle_domain_sync_state(struct device *dev)
+{
+       /*
+        * All devices have now been attached/probed to the PM domain
+        * topology, hence it's fine to allow domain states to be picked.
+        */
+       sbi_cpuidle_pd_allow_domain_state = true;
+}
+
+#ifdef CONFIG_DT_IDLE_GENPD
+
+static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)
+{
+       struct genpd_power_state *state = &pd->states[pd->state_idx];
+       u32 *pd_state;
+
+       if (!state->data)
+               return 0;
+
+       if (!sbi_cpuidle_pd_allow_domain_state)
+               return -EBUSY;
+
+       /* OSI mode is enabled, set the corresponding domain state. */
+       pd_state = state->data;
+       sbi_set_domain_state(*pd_state);
+
+       return 0;
+}
+
+struct sbi_pd_provider {
+       struct list_head link;
+       struct device_node *node;
+};
+
+static LIST_HEAD(sbi_pd_providers);
+
+static int sbi_pd_init(struct device_node *np)
+{
+       struct generic_pm_domain *pd;
+       struct sbi_pd_provider *pd_provider;
+       struct dev_power_governor *pd_gov;
+       int ret = -ENOMEM, state_count = 0;
+
+       pd = dt_idle_pd_alloc(np, sbi_dt_parse_state_node);
+       if (!pd)
+               goto out;
+
+       pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
+       if (!pd_provider)
+               goto free_pd;
+
+       pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
+
+       /* Allow power off when OSI is available. */
+       if (sbi_cpuidle_use_osi)
+               pd->power_off = sbi_cpuidle_pd_power_off;
+       else
+               pd->flags |= GENPD_FLAG_ALWAYS_ON;
+
+       /* Use governor for CPU PM domains if it has some states to manage. */
+       pd_gov = state_count > 0 ? &pm_domain_cpu_gov : NULL;
+
+       ret = pm_genpd_init(pd, pd_gov, false);
+       if (ret)
+               goto free_pd_prov;
+
+       ret = of_genpd_add_provider_simple(np, pd);
+       if (ret)
+               goto remove_pd;
+
+       pd_provider->node = of_node_get(np);
+       list_add(&pd_provider->link, &sbi_pd_providers);
+
+       pr_debug("init PM domain %s\n", pd->name);
+       return 0;
+
+remove_pd:
+       pm_genpd_remove(pd);
+free_pd_prov:
+       kfree(pd_provider);
+free_pd:
+       dt_idle_pd_free(pd);
+out:
+       pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
+       return ret;
+}
+
+static void sbi_pd_remove(void)
+{
+       struct sbi_pd_provider *pd_provider, *it;
+       struct generic_pm_domain *genpd;
+
+       list_for_each_entry_safe(pd_provider, it, &sbi_pd_providers, link) {
+               of_genpd_del_provider(pd_provider->node);
+
+               genpd = of_genpd_remove_last(pd_provider->node);
+               if (!IS_ERR(genpd))
+                       kfree(genpd);
+
+               of_node_put(pd_provider->node);
+               list_del(&pd_provider->link);
+               kfree(pd_provider);
+       }
+}
+
+static int sbi_genpd_probe(struct device_node *np)
+{
+       struct device_node *node;
+       int ret = 0, pd_count = 0;
+
+       if (!np)
+               return -ENODEV;
+
+       /*
+        * Parse child nodes for the "#power-domain-cells" property and
+        * initialize a genpd/genpd-of-provider pair when it's found.
+        */
+       for_each_child_of_node(np, node) {
+               if (!of_find_property(node, "#power-domain-cells", NULL))
+                       continue;
+
+               ret = sbi_pd_init(node);
+               if (ret)
+                       goto put_node;
+
+               pd_count++;
+       }
+
+       /* Bail out if not using the hierarchical CPU topology. */
+       if (!pd_count)
+               goto no_pd;
+
+       /* Link genpd masters/subdomains to model the CPU topology. */
+       ret = dt_idle_pd_init_topology(np);
+       if (ret)
+               goto remove_pd;
+
+       return 0;
+
+put_node:
+       of_node_put(node);
+remove_pd:
+       sbi_pd_remove();
+       pr_err("failed to create CPU PM domains ret=%d\n", ret);
+no_pd:
+       return ret;
+}
+
+#else
+
+static inline int sbi_genpd_probe(struct device_node *np)
+{
+       return 0;
+}
+
+#endif
+
+static int sbi_cpuidle_probe(struct platform_device *pdev)
+{
+       int cpu, ret;
+       struct cpuidle_driver *drv;
+       struct cpuidle_device *dev;
+       struct device_node *np, *pds_node;
+
+       /* Detect OSI support based on CPU DT nodes */
+       sbi_cpuidle_use_osi = true;
+       for_each_possible_cpu(cpu) {
+               np = of_cpu_device_node_get(cpu);
+               if (np &&
+                   of_find_property(np, "power-domains", NULL) &&
+                   of_find_property(np, "power-domain-names", NULL)) {
+                       continue;
+               } else {
+                       sbi_cpuidle_use_osi = false;
+                       break;
+               }
+       }
+
+       /* Populate generic power domains from DT nodes */
+       pds_node = of_find_node_by_path("/cpus/power-domains");
+       if (pds_node) {
+               ret = sbi_genpd_probe(pds_node);
+               of_node_put(pds_node);
+               if (ret)
+                       return ret;
+       }
+
+       /* Initialize CPU idle driver for each CPU */
+       for_each_possible_cpu(cpu) {
+               ret = sbi_cpuidle_init_cpu(&pdev->dev, cpu);
+               if (ret) {
+                       pr_debug("HART%ld: idle driver init failed\n",
+                                cpuid_to_hartid_map(cpu));
+                       goto out_fail;
+               }
+       }
+
+       /* Setup CPU hotplut notifiers */
+       sbi_idle_init_cpuhp();
+
+       pr_info("idle driver registered for all CPUs\n");
+
+       return 0;
+
+out_fail:
+       while (--cpu >= 0) {
+               dev = per_cpu(cpuidle_devices, cpu);
+               drv = cpuidle_get_cpu_driver(dev);
+               cpuidle_unregister(drv);
+               sbi_cpuidle_deinit_cpu(cpu);
+       }
+
+       return ret;
+}
+
+static struct platform_driver sbi_cpuidle_driver = {
+       .probe = sbi_cpuidle_probe,
+       .driver = {
+               .name = "sbi-cpuidle",
+               .sync_state = sbi_cpuidle_domain_sync_state,
+       },
+};
+
+static int __init sbi_cpuidle_init(void)
+{
+       int ret;
+       struct platform_device *pdev;
+
+       /*
+        * The SBI HSM suspend function is only available when:
+        * 1) SBI version is 0.3 or higher
+        * 2) SBI HSM extension is available
+        */
+       if ((sbi_spec_version < sbi_mk_version(0, 3)) ||
+           sbi_probe_extension(SBI_EXT_HSM) <= 0) {
+               pr_info("HSM suspend not available\n");
+               return 0;
+       }
+
+       ret = platform_driver_register(&sbi_cpuidle_driver);
+       if (ret)
+               return ret;
+
+       pdev = platform_device_register_simple("sbi-cpuidle",
+                                               -1, NULL, 0);
+       if (IS_ERR(pdev)) {
+               platform_driver_unregister(&sbi_cpuidle_driver);
+               return PTR_ERR(pdev);
+       }
+
+       return 0;
+}
+device_initcall(sbi_cpuidle_init);
--

2.25.1

--
kvm-riscv mailing list
kvm-riscv at lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kvm-riscv

Quoted 6 lines · Anup Patel

From: Anup Patel <[email protected]>

The RISC-V SBI HSM extension provides HSM suspend call which can be used by Linux RISC-V to enter platform specific low-power state.

Quoted 6 lines

This patch adds a CPU idle driver based on RISC-V SBI calls which will populate idle states from device tree and use SBI calls to entry these idle states.

Signed-off-by Anup Patel <[email protected]>

Reviewed-by Anup Patel <[email protected]>

Signed-off-by ?

Quoted 715 lines

---
 MAINTAINERS                         |   7 +
 drivers/cpuidle/Kconfig             |   5 +
 drivers/cpuidle/Kconfig.riscv       |  15 +
 drivers/cpuidle/Makefile            |   4 +
 drivers/cpuidle/cpuidle-riscv-sbi.c | 627 ++++++++++++++++++++++++++++
 5 files changed, 658 insertions(+)
 create mode 100644 drivers/cpuidle/Kconfig.riscv
 create mode 100644 drivers/cpuidle/cpuidle-riscv-sbi.c

MAINTAINERS +7 -0

index 0c67ebe7f07e..15c63a717458 100644
@@ -5058,6 +5058,13 @@ S:       Supported
 F:     drivers/cpuidle/dt_idle_genpd.c
 F:     drivers/cpuidle/dt_idle_genpd.h
 
+CPUIDLE DRIVER - RISC-V SBI
+M:     Anup Patel <[email protected]>
+L:     linux-pm at vger.kernel.org
+L:     linux-riscv at lists.infradead.org
+S:     Maintained
+F:     drivers/cpuidle/cpuidle-riscv-sbi.c
+
 CRAMFS FILESYSTEM
 M:     Nicolas Pitre <[email protected]>
 S:     Maintained

drivers/cpuidle/Kconfig +5 -0

index f1afe7ab6b54..ff71dd662880 100644
@@ -66,6 +66,11 @@ depends on PPC
 source "drivers/cpuidle/Kconfig.powerpc"
 endmenu
 
+menu "RISC-V CPU Idle Drivers"
+depends on RISCV
+source "drivers/cpuidle/Kconfig.riscv"
+endmenu
+
 config HALTPOLL_CPUIDLE
        tristate "Halt poll cpuidle driver"
        depends on X86 && KVM_GUEST

drivers/cpuidle/Kconfig.riscv new file +15 -0

new file mode 100644
index 000000000000..78518c26af74
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# RISC-V CPU Idle drivers
+#
+
+config RISCV_SBI_CPUIDLE
+       bool "RISC-V SBI CPU idle Driver"
+       depends on RISCV_SBI
+       select DT_IDLE_STATES
+       select CPU_IDLE_MULTIPLE_DRIVERS
+       select DT_IDLE_GENPD if PM_GENERIC_DOMAINS_OF
+       help
+         Select this option to enable RISC-V SBI firmware based CPU idle
+         driver for RISC-V systems. This drivers also supports hierarchical
+         DT based layout of the idle state.

drivers/cpuidle/Makefile +4 -0

index 11a26cef279f..d103342b7cfc 100644
@@ -35,3 +35,7 @@ obj-$(CONFIG_MIPS_CPS_CPUIDLE)                += cpuidle-cps.o
 # POWERPC drivers
 obj-$(CONFIG_PSERIES_CPUIDLE)          += cpuidle-pseries.o
 obj-$(CONFIG_POWERNV_CPUIDLE)          += cpuidle-powernv.o
+
+###############################################################################
+# RISC-V drivers
+obj-$(CONFIG_RISCV_SBI_CPUIDLE)                += cpuidle-riscv-sbi.o

drivers/cpuidle/cpuidle-riscv-sbi.c new file +627 -1

new file mode 100644
index 000000000000..b459eda2cd37
@@ -0,0 +1,627 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * RISC-V SBI CPU idle driver.
+ *
+ * Copyright (c) 2021 Western Digital Corporation or its affiliates.
+ * Copyright (c) 2022 Ventana Micro Systems Inc.
+ */
+
+#define pr_fmt(fmt) "cpuidle-riscv-sbi: " fmt
+
+#include <linux/cpuidle.h>
+#include <linux/cpumask.h>
+#include <linux/cpu_pm.h>
+#include <linux/cpu_cooling.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/pm_runtime.h>
+#include <asm/cpuidle.h>
+#include <asm/sbi.h>
+#include <asm/suspend.h>
+
+#include "dt_idle_states.h"
+#include "dt_idle_genpd.h"
+
+struct sbi_cpuidle_data {
+       u32 *states;
+       struct device *dev;
+};
+
+struct sbi_domain_state {
+       bool available;
+       u32 state;
+};
+
+static DEFINE_PER_CPU_READ_MOSTLY(struct sbi_cpuidle_data, sbi_cpuidle_data);
+static DEFINE_PER_CPU(struct sbi_domain_state, domain_state);
+static bool sbi_cpuidle_use_osi;
+static bool sbi_cpuidle_use_cpuhp;
+static bool sbi_cpuidle_pd_allow_domain_state;
+
+static inline void sbi_set_domain_state(u32 state)
+{
+       struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
+
+       data->available = true;
+       data->state = state;
+}
+
+static inline u32 sbi_get_domain_state(void)
+{
+       struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
+
+       return data->state;
+}
+
+static inline void sbi_clear_domain_state(void)
+{
+       struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
+
+       data->available = false;
+}
+
+static inline bool sbi_is_domain_state_available(void)
+{
+       struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
+
+       return data->available;
+}
+
+static int sbi_suspend_finisher(unsigned long suspend_type,
+                               unsigned long resume_addr,
+                               unsigned long opaque)
+{
+       struct sbiret ret;
+
+       ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_SUSPEND,
+                       suspend_type, resume_addr, opaque, 0, 0, 0);
+
+       return (ret.error) ? sbi_err_map_linux_errno(ret.error) : 0;
+}
+
+static int sbi_suspend(u32 state)
+{
+       if (state & SBI_HSM_SUSP_NON_RET_BIT)
+               return cpu_suspend(state, sbi_suspend_finisher);
+       else
+               return sbi_suspend_finisher(state, 0, 0);
+}
+
+static int sbi_cpuidle_enter_state(struct cpuidle_device *dev,
+                                  struct cpuidle_driver *drv, int idx)
+{
+       u32 *states = __this_cpu_read(sbi_cpuidle_data.states);
+
+       return CPU_PM_CPU_IDLE_ENTER_PARAM(sbi_suspend, idx, states[idx]);
+}
+
+static int __sbi_enter_domain_idle_state(struct cpuidle_device *dev,
+                                         struct cpuidle_driver *drv, int idx,
+                                         bool s2idle)
+{
+       struct sbi_cpuidle_data *data = this_cpu_ptr(&sbi_cpuidle_data);
+       u32 *states = data->states;
+       struct device *pd_dev = data->dev;
+       u32 state;
+       int ret;
+
+       ret = cpu_pm_enter();
+       if (ret)
+               return -1;
+
+       /* Do runtime PM to manage a hierarchical CPU toplogy. */
+       rcu_irq_enter_irqson();
+       if (s2idle)
+               dev_pm_genpd_suspend(pd_dev);
+       else
+               pm_runtime_put_sync_suspend(pd_dev);
+       rcu_irq_exit_irqson();
+
+       if (sbi_is_domain_state_available())
+               state = sbi_get_domain_state();
+       else
+               state = states[idx];
+
+       ret = sbi_suspend(state) ? -1 : idx;
+
+       rcu_irq_enter_irqson();
+       if (s2idle)
+               dev_pm_genpd_resume(pd_dev);
+       else
+               pm_runtime_get_sync(pd_dev);
+       rcu_irq_exit_irqson();
+
+       cpu_pm_exit();
+
+       /* Clear the domain state to start fresh when back from idle. */
+       sbi_clear_domain_state();
+       return ret;
+}
+
+static int sbi_enter_domain_idle_state(struct cpuidle_device *dev,
+                                      struct cpuidle_driver *drv, int idx)
+{
+       return __sbi_enter_domain_idle_state(dev, drv, idx, false);
+}
+
+static int sbi_enter_s2idle_domain_idle_state(struct cpuidle_device *dev,
+                                             struct cpuidle_driver *drv,
+                                             int idx)
+{
+       return __sbi_enter_domain_idle_state(dev, drv, idx, true);
+}
+
+static int sbi_cpuidle_cpuhp_up(unsigned int cpu)
+{
+       struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);
+
+       if (pd_dev)
+               pm_runtime_get_sync(pd_dev);
+
+       return 0;
+}
+
+static int sbi_cpuidle_cpuhp_down(unsigned int cpu)
+{
+       struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);
+
+       if (pd_dev) {
+               pm_runtime_put_sync(pd_dev);
+               /* Clear domain state to start fresh at next online. */
+               sbi_clear_domain_state();
+       }
+
+       return 0;
+}
+
+static void sbi_idle_init_cpuhp(void)
+{
+       int err;
+
+       if (!sbi_cpuidle_use_cpuhp)
+               return;
+
+       err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,
+                                       "cpuidle/sbi:online",
+                                       sbi_cpuidle_cpuhp_up,
+                                       sbi_cpuidle_cpuhp_down);
+       if (err)
+               pr_warn("Failed %d while setup cpuhp state\n", err);
+}
+
+static const struct of_device_id sbi_cpuidle_state_match[] = {
+       { .compatible = "riscv,idle-state",
+         .data = sbi_cpuidle_enter_state },
+       { },
+};
+
+static bool sbi_suspend_state_is_valid(u32 state)
+{
+       if (state > SBI_HSM_SUSPEND_RET_DEFAULT &&
+           state < SBI_HSM_SUSPEND_RET_PLATFORM)
+               return false;
+       if (state > SBI_HSM_SUSPEND_NON_RET_DEFAULT &&
+           state < SBI_HSM_SUSPEND_NON_RET_PLATFORM)
+               return false;
+       return true;
+}
+
+static int sbi_dt_parse_state_node(struct device_node *np, u32 *state)
+{
+       int err = of_property_read_u32(np, "riscv,sbi-suspend-param", state);
+
+       if (err) {
+               pr_warn("%pOF missing riscv,sbi-suspend-param property\n", np);
+               return err;
+       }
+
+       if (!sbi_suspend_state_is_valid(*state)) {
+               pr_warn("Invalid SBI suspend state %#x\n", *state);
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+static int sbi_dt_cpu_init_topology(struct cpuidle_driver *drv,
+                                    struct sbi_cpuidle_data *data,
+                                    unsigned int state_count, int cpu)
+{
+       /* Currently limit the hierarchical topology to be used in OSI mode. */
+       if (!sbi_cpuidle_use_osi)
+               return 0;
+
+       data->dev = dt_idle_attach_cpu(cpu, "sbi");
+       if (IS_ERR_OR_NULL(data->dev))
+               return PTR_ERR_OR_ZERO(data->dev);
+
+       /*
+        * Using the deepest state for the CPU to trigger a potential selection
+        * of a shared state for the domain, assumes the domain states are all
+        * deeper states.
+        */
+       drv->states[state_count - 1].enter = sbi_enter_domain_idle_state;
+       drv->states[state_count - 1].enter_s2idle =
+                                       sbi_enter_s2idle_domain_idle_state;
+       sbi_cpuidle_use_cpuhp = true;
+
+       return 0;
+}
+
+static int sbi_cpuidle_dt_init_states(struct device *dev,
+                                       struct cpuidle_driver *drv,
+                                       unsigned int cpu,
+                                       unsigned int state_count)
+{
+       struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
+       struct device_node *state_node;
+       struct device_node *cpu_node;
+       u32 *states;
+       int i, ret;
+
+       cpu_node = of_cpu_device_node_get(cpu);
+       if (!cpu_node)
+               return -ENODEV;
+
+       states = devm_kcalloc(dev, state_count, sizeof(*states), GFP_KERNEL);
+       if (!states) {
+               ret = -ENOMEM;
+               goto fail;
+       }
+
+       /* Parse SBI specific details from state DT nodes */
+       for (i = 1; i < state_count; i++) {
+               state_node = of_get_cpu_state_node(cpu_node, i - 1);
+               if (!state_node)
+                       break;
+
+               ret = sbi_dt_parse_state_node(state_node, &states[i]);
+               of_node_put(state_node);
+
+               if (ret)
+                       return ret;
+
+               pr_debug("sbi-state %#x index %d\n", states[i], i);
+       }
+       if (i != state_count) {
+               ret = -ENODEV;
+               goto fail;
+       }
+
+       /* Initialize optional data, used for the hierarchical topology. */
+       ret = sbi_dt_cpu_init_topology(drv, data, state_count, cpu);
+       if (ret < 0)
+               return ret;
+
+       /* Store states in the per-cpu struct. */
+       data->states = states;
+
+fail:
+       of_node_put(cpu_node);
+
+       return ret;
+}
+
+static void sbi_cpuidle_deinit_cpu(int cpu)
+{
+       struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
+
+       dt_idle_detach_cpu(data->dev);
+       sbi_cpuidle_use_cpuhp = false;
+}
+
+static int sbi_cpuidle_init_cpu(struct device *dev, int cpu)
+{
+       struct cpuidle_driver *drv;
+       unsigned int state_count = 0;
+       int ret = 0;
+
+       drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
+       if (!drv)
+               return -ENOMEM;
+
+       drv->name = "sbi_cpuidle";
+       drv->owner = THIS_MODULE;
+       drv->cpumask = (struct cpumask *)cpumask_of(cpu);
+
+       /* RISC-V architectural WFI to be represented as state index 0. */
+       drv->states[0].enter = sbi_cpuidle_enter_state;
+       drv->states[0].exit_latency = 1;
+       drv->states[0].target_residency = 1;
+       drv->states[0].power_usage = UINT_MAX;
+       strcpy(drv->states[0].name, "WFI");
+       strcpy(drv->states[0].desc, "RISC-V WFI");
+
+       /*
+        * If no DT idle states are detected (ret == 0) let the driver
+        * initialization fail accordingly since there is no reason to
+        * initialize the idle driver if only wfi is supported, the
+        * default archictectural back-end already executes wfi
+        * on idle entry.
+        */
+       ret = dt_init_idle_driver(drv, sbi_cpuidle_state_match, 1);
+       if (ret <= 0) {
+               pr_debug("HART%ld: failed to parse DT idle states\n",
+                        cpuid_to_hartid_map(cpu));
+               return ret ? : -ENODEV;
+       }
+       state_count = ret + 1; /* Include WFI state as well */
+
+       /* Initialize idle states from DT. */
+       ret = sbi_cpuidle_dt_init_states(dev, drv, cpu, state_count);
+       if (ret) {
+               pr_err("HART%ld: failed to init idle states\n",
+                      cpuid_to_hartid_map(cpu));
+               return ret;
+       }
+
+       ret = cpuidle_register(drv, NULL);
+       if (ret)
+               goto deinit;
+
+       cpuidle_cooling_register(drv);
+
+       return 0;
+deinit:
+       sbi_cpuidle_deinit_cpu(cpu);
+       return ret;
+}
+
+static void sbi_cpuidle_domain_sync_state(struct device *dev)
+{
+       /*
+        * All devices have now been attached/probed to the PM domain
+        * topology, hence it's fine to allow domain states to be picked.
+        */
+       sbi_cpuidle_pd_allow_domain_state = true;
+}
+
+#ifdef CONFIG_DT_IDLE_GENPD
+
+static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)
+{
+       struct genpd_power_state *state = &pd->states[pd->state_idx];
+       u32 *pd_state;
+
+       if (!state->data)
+               return 0;
+
+       if (!sbi_cpuidle_pd_allow_domain_state)
+               return -EBUSY;
+
+       /* OSI mode is enabled, set the corresponding domain state. */
+       pd_state = state->data;
+       sbi_set_domain_state(*pd_state);
+
+       return 0;
+}
+
+struct sbi_pd_provider {
+       struct list_head link;
+       struct device_node *node;
+};
+
+static LIST_HEAD(sbi_pd_providers);
+
+static int sbi_pd_init(struct device_node *np)
+{
+       struct generic_pm_domain *pd;
+       struct sbi_pd_provider *pd_provider;
+       struct dev_power_governor *pd_gov;
+       int ret = -ENOMEM, state_count = 0;
+
+       pd = dt_idle_pd_alloc(np, sbi_dt_parse_state_node);
+       if (!pd)
+               goto out;
+
+       pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
+       if (!pd_provider)
+               goto free_pd;
+
+       pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
+
+       /* Allow power off when OSI is available. */
+       if (sbi_cpuidle_use_osi)
+               pd->power_off = sbi_cpuidle_pd_power_off;
+       else
+               pd->flags |= GENPD_FLAG_ALWAYS_ON;
+
+       /* Use governor for CPU PM domains if it has some states to manage. */
+       pd_gov = state_count > 0 ? &pm_domain_cpu_gov : NULL;
+
+       ret = pm_genpd_init(pd, pd_gov, false);
+       if (ret)
+               goto free_pd_prov;
+
+       ret = of_genpd_add_provider_simple(np, pd);
+       if (ret)
+               goto remove_pd;
+
+       pd_provider->node = of_node_get(np);
+       list_add(&pd_provider->link, &sbi_pd_providers);
+
+       pr_debug("init PM domain %s\n", pd->name);
+       return 0;
+
+remove_pd:
+       pm_genpd_remove(pd);
+free_pd_prov:
+       kfree(pd_provider);
+free_pd:
+       dt_idle_pd_free(pd);
+out:
+       pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
+       return ret;
+}
+
+static void sbi_pd_remove(void)
+{
+       struct sbi_pd_provider *pd_provider, *it;
+       struct generic_pm_domain *genpd;
+
+       list_for_each_entry_safe(pd_provider, it, &sbi_pd_providers, link) {
+               of_genpd_del_provider(pd_provider->node);
+
+               genpd = of_genpd_remove_last(pd_provider->node);
+               if (!IS_ERR(genpd))
+                       kfree(genpd);
+
+               of_node_put(pd_provider->node);
+               list_del(&pd_provider->link);
+               kfree(pd_provider);
+       }
+}
+
+static int sbi_genpd_probe(struct device_node *np)
+{
+       struct device_node *node;
+       int ret = 0, pd_count = 0;
+
+       if (!np)
+               return -ENODEV;
+
+       /*
+        * Parse child nodes for the "#power-domain-cells" property and
+        * initialize a genpd/genpd-of-provider pair when it's found.
+        */
+       for_each_child_of_node(np, node) {
+               if (!of_find_property(node, "#power-domain-cells", NULL))
+                       continue;
+
+               ret = sbi_pd_init(node);
+               if (ret)
+                       goto put_node;
+
+               pd_count++;
+       }
+
+       /* Bail out if not using the hierarchical CPU topology. */
+       if (!pd_count)
+               goto no_pd;
+
+       /* Link genpd masters/subdomains to model the CPU topology. */
+       ret = dt_idle_pd_init_topology(np);
+       if (ret)
+               goto remove_pd;
+
+       return 0;
+
+put_node:
+       of_node_put(node);
+remove_pd:
+       sbi_pd_remove();
+       pr_err("failed to create CPU PM domains ret=%d\n", ret);
+no_pd:
+       return ret;
+}
+
+#else
+
+static inline int sbi_genpd_probe(struct device_node *np)
+{
+       return 0;
+}
+
+#endif
+
+static int sbi_cpuidle_probe(struct platform_device *pdev)
+{
+       int cpu, ret;
+       struct cpuidle_driver *drv;
+       struct cpuidle_device *dev;
+       struct device_node *np, *pds_node;
+
+       /* Detect OSI support based on CPU DT nodes */
+       sbi_cpuidle_use_osi = true;
+       for_each_possible_cpu(cpu) {
+               np = of_cpu_device_node_get(cpu);
+               if (np &&
+                   of_find_property(np, "power-domains", NULL) &&
+                   of_find_property(np, "power-domain-names", NULL)) {
+                       continue;
+               } else {
+                       sbi_cpuidle_use_osi = false;
+                       break;
+               }
+       }
+
+       /* Populate generic power domains from DT nodes */
+       pds_node = of_find_node_by_path("/cpus/power-domains");
+       if (pds_node) {
+               ret = sbi_genpd_probe(pds_node);
+               of_node_put(pds_node);
+               if (ret)
+                       return ret;
+       }
+
+       /* Initialize CPU idle driver for each CPU */
+       for_each_possible_cpu(cpu) {
+               ret = sbi_cpuidle_init_cpu(&pdev->dev, cpu);
+               if (ret) {
+                       pr_debug("HART%ld: idle driver init failed\n",
+                                cpuid_to_hartid_map(cpu));
+                       goto out_fail;
+               }
+       }
+
+       /* Setup CPU hotplut notifiers */
+       sbi_idle_init_cpuhp();
+
+       pr_info("idle driver registered for all CPUs\n");
+
+       return 0;
+
+out_fail:
+       while (--cpu >= 0) {
+               dev = per_cpu(cpuidle_devices, cpu);
+               drv = cpuidle_get_cpu_driver(dev);
+               cpuidle_unregister(drv);
+               sbi_cpuidle_deinit_cpu(cpu);
+       }
+
+       return ret;
+}
+
+static struct platform_driver sbi_cpuidle_driver = {
+       .probe = sbi_cpuidle_probe,
+       .driver = {
+               .name = "sbi-cpuidle",
+               .sync_state = sbi_cpuidle_domain_sync_state,
+       },
+};
+
+static int __init sbi_cpuidle_init(void)
+{
+       int ret;
+       struct platform_device *pdev;
+
+       /*
+        * The SBI HSM suspend function is only available when:
+        * 1) SBI version is 0.3 or higher
+        * 2) SBI HSM extension is available
+        */
+       if ((sbi_spec_version < sbi_mk_version(0, 3)) ||
+           sbi_probe_extension(SBI_EXT_HSM) <= 0) {
+               pr_info("HSM suspend not available\n");
+               return 0;
+       }
+
+       ret = platform_driver_register(&sbi_cpuidle_driver);
+       if (ret)
+               return ret;
+
+       pdev = platform_device_register_simple("sbi-cpuidle",
+                                               -1, NULL, 0);
+       if (IS_ERR(pdev)) {
+               platform_driver_unregister(&sbi_cpuidle_driver);
+               return PTR_ERR(pdev);
+       }
+
+       return 0;
+}
+device_initcall(sbi_cpuidle_init);
--

2.25.1

Quoted 4 lines

--
kvm-riscv mailing list
kvm-riscv at lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kvm-riscv

--
Best Regards
Guo Ren

ML: https://lore.kernel.org/linux-csky/

From: Anup Patel <[email protected]>

The RISC-V CPU idle states will be described in under the /cpus/idle-states DT node in the same way as ARM CPU idle states.

This patch adds common bindings documentation for both ARM and RISC-V idle states.

Signed-off-by Anup Patel <[email protected]>

Signed-off-by Anup Patel <[email protected]>

Reviewed-by Rob Herring <[email protected]>

---
 .../bindings/arm/msm/qcom,idle-state.txt      |   2 +-
 .../devicetree/bindings/arm/psci.yaml         |   2 +-
 .../bindings/{arm => cpu}/idle-states.yaml    | 228 ++++++++++++++++--
 .../devicetree/bindings/riscv/cpus.yaml       |   6 +
 4 files changed, 219 insertions(+), 19 deletions(-)
 rename Documentation/devicetree/bindings/{arm => cpu}/idle-states.yaml (74%)

Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt +1 -1

index 6ce0b212ec6d..606b4b1b709d 100644
@@ -81,4 +81,4 @@ Example:
                };
        };
 
-[1]. Documentation/devicetree/bindings/arm/idle-states.yaml
+[1]. Documentation/devicetree/bindings/cpu/idle-states.yaml

Documentation/devicetree/bindings/arm/psci.yaml +1 -1

index 8b77cf83a095..dd83ef278af0 100644
@@ -101,7 +101,7 @@ properties:
       bindings in [1]) must specify this property.
 
       [1] Kernel documentation - ARM idle states bindings
-        Documentation/devicetree/bindings/arm/idle-states.yaml
+        Documentation/devicetree/bindings/cpu/idle-states.yaml
 
 patternProperties:
   "^power-domain-":

Documentation/devicetree/bindings/cpu/idle-states.yaml renamed from Documentation/devicetree/bindings/arm/idle-states.yaml +211 -17

similarity index 74%
rename from Documentation/devicetree/bindings/arm/idle-states.yaml
rename to Documentation/devicetree/bindings/cpu/idle-states.yaml
index 52bce5dbb11f..95506ffb816c 100644
@@ -1,25 +1,30 @@
 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
 %YAML 1.2
 ---
-$id: http://devicetree.org/schemas/arm/idle-states.yaml#
+$id: http://devicetree.org/schemas/cpu/idle-states.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: ARM idle states binding description
+title: Idle states binding description
 
 maintainers:
   - Lorenzo Pieralisi <[email protected]>
+  - Anup Patel <[email protected]>
 
 description: |+
   ==========================================
   1 - Introduction
   ==========================================
 
-  ARM systems contain HW capable of managing power consumption dynamically,
-  where cores can be put in different low-power states (ranging from simple wfi
-  to power gating) according to OS PM policies. The CPU states representing the
-  range of dynamic idle states that a processor can enter at run-time, can be
-  specified through device tree bindings representing the parameters required to
-  enter/exit specific idle states on a given processor.
+  ARM and RISC-V systems contain HW capable of managing power consumption
+  dynamically, where cores can be put in different low-power states (ranging
+  from simple wfi to power gating) according to OS PM policies. The CPU states
+  representing the range of dynamic idle states that a processor can enter at
+  run-time, can be specified through device tree bindings representing the
+  parameters required to enter/exit specific idle states on a given processor.
+
+  ==========================================
+  2 - ARM idle states
+  ==========================================
 
   According to the Server Base System Architecture document (SBSA, [3]), the
   power states an ARM CPU can be put into are identified by the following list:

@@ -43,8 +48,23 @@ description: |+
   The device tree binding definition for ARM idle states is the subject of this
   document.
 
+  ==========================================
+  3 - RISC-V idle states
+  ==========================================
+
+  On RISC-V systems, the HARTs (or CPUs) [6] can be put in platform specific
+  suspend (or idle) states (ranging from simple WFI, power gating, etc). The
+  RISC-V SBI v0.3 (or higher) [7] hart state management extension provides a
+  standard mechanism for OS to request HART state transitions.
+
+  The platform specific suspend (or idle) states of a hart can be either
+  retentive or non-rententive in nature. A retentive suspend state will
+  preserve HART registers and CSR values for all privilege modes whereas
+  a non-retentive suspend state will not preserve HART registers and CSR
+  values.
+
   ===========================================
-  2 - idle-states definitions
+  4 - idle-states definitions
   ===========================================
 
   Idle states are characterized for a specific system through a set of

@@ -211,10 +231,10 @@ description: |+
   properties specification that is the subject of the following sections.
 
   ===========================================
-  3 - idle-states node
+  5 - idle-states node
   ===========================================
 
-  ARM processor idle states are defined within the idle-states node, which is
+  The processor idle states are defined within the idle-states node, which is
   a direct child of the cpus node [1] and provides a container where the
   processor idle states, defined as device tree nodes, are listed.
 

@@ -223,7 +243,7 @@ description: |+
   just supports idle_standby, an idle-states node is not required.
 
   ===========================================
-  4 - References
+  6 - References
   ===========================================
 
   [1] ARM Linux Kernel documentation - CPUs bindings

@@ -238,9 +258,15 @@ description: |+
   [4] ARM Architecture Reference Manuals
       http://infocenter.arm.com/help/index.jsp
 
-  [6] ARM Linux Kernel documentation - Booting AArch64 Linux
+  [5] ARM Linux Kernel documentation - Booting AArch64 Linux
       Documentation/arm64/booting.rst
 
+  [6] RISC-V Linux Kernel documentation - CPUs bindings
+      Documentation/devicetree/bindings/riscv/cpus.yaml
+
+  [7] RISC-V Supervisor Binary Interface (SBI)
+      http://github.com/riscv/riscv-sbi-doc/riscv-sbi.adoc
+
 properties:
   $nodename:
     const: idle-states

@@ -253,7 +279,7 @@ properties:
       On ARM 32-bit systems this property is optional
 
       This assumes that the "enable-method" property is set to "psci" in the cpu
-      node[6] that is responsible for setting up CPU idle management in the OS
+      node[5] that is responsible for setting up CPU idle management in the OS
       implementation.
     const: psci
 

@@ -265,8 +291,8 @@ patternProperties:
       as follows.
 
       The idle state entered by executing the wfi instruction (idle_standby
-      SBSA,[3][4]) is considered standard on all ARM platforms and therefore
-      must not be listed.
+      SBSA,[3][4]) is considered standard on all ARM and RISC-V platforms and
+      therefore must not be listed.
 
       In addition to the properties listed above, a state node may require
       additional properties specific to the entry-method defined in the

@@ -275,7 +301,27 @@ patternProperties:
 
     properties:
       compatible:
-        const: arm,idle-state
+        enum:
+          - arm,idle-state
+          - riscv,idle-state
+
+      arm,psci-suspend-param:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: |
+          power_state parameter to pass to the ARM PSCI suspend call.
+
+          Device tree nodes that require usage of PSCI CPU_SUSPEND function
+          (i.e. idle states node with entry-method property is set to "psci")
+          must specify this property.
+
+      riscv,sbi-suspend-param:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: |
+          suspend_type parameter to pass to the RISC-V SBI HSM suspend call.
+
+          This property is required in idle state nodes of device tree meant
+          for RISC-V systems. For more details on the suspend_type parameter
+          refer the SBI specifiation v0.3 (or higher) [7].
 
       local-timer-stop:
         description:

@@ -317,6 +363,8 @@ patternProperties:
         description:
           A string used as a descriptive name for the idle state.
 
+    additionalProperties: false
+
     required:
       - compatible
       - entry-latency-us

@@ -658,4 +706,150 @@ examples:
         };
     };
 
+  - |
+    // Example 3 (RISC-V 64-bit, 4-cpu systems, two clusters):
+
+    cpus {
+        #size-cells = <0>;
+        #address-cells = <1>;
+
+        cpu at 0 {
+            device_type = "cpu";
+            compatible = "riscv";
+            reg = <0x0>;
+            riscv,isa = "rv64imafdc";
+            mmu-type = "riscv,sv48";
+            cpu-idle-states = <&CPU_RET_0_0 &CPU_NONRET_0_0
+                            &CLUSTER_RET_0 &CLUSTER_NONRET_0>;
+
+            cpu_intc0: interrupt-controller {
+                #interrupt-cells = <1>;
+                compatible = "riscv,cpu-intc";
+                interrupt-controller;
+            };
+        };
+
+        cpu at 1 {
+            device_type = "cpu";
+            compatible = "riscv";
+            reg = <0x1>;
+            riscv,isa = "rv64imafdc";
+            mmu-type = "riscv,sv48";
+            cpu-idle-states = <&CPU_RET_0_0 &CPU_NONRET_0_0
+                            &CLUSTER_RET_0 &CLUSTER_NONRET_0>;
+
+            cpu_intc1: interrupt-controller {
+                #interrupt-cells = <1>;
+                compatible = "riscv,cpu-intc";
+                interrupt-controller;
+            };
+        };
+
+        cpu at 10 {
+            device_type = "cpu";
+            compatible = "riscv";
+            reg = <0x10>;
+            riscv,isa = "rv64imafdc";
+            mmu-type = "riscv,sv48";
+            cpu-idle-states = <&CPU_RET_1_0 &CPU_NONRET_1_0
+                            &CLUSTER_RET_1 &CLUSTER_NONRET_1>;
+
+            cpu_intc10: interrupt-controller {
+                #interrupt-cells = <1>;
+                compatible = "riscv,cpu-intc";
+                interrupt-controller;
+            };
+        };
+
+        cpu at 11 {
+            device_type = "cpu";
+            compatible = "riscv";
+            reg = <0x11>;
+            riscv,isa = "rv64imafdc";
+            mmu-type = "riscv,sv48";
+            cpu-idle-states = <&CPU_RET_1_0 &CPU_NONRET_1_0
+                            &CLUSTER_RET_1 &CLUSTER_NONRET_1>;
+
+            cpu_intc11: interrupt-controller {
+                #interrupt-cells = <1>;
+                compatible = "riscv,cpu-intc";
+                interrupt-controller;
+            };
+        };
+
+        idle-states {
+            CPU_RET_0_0: cpu-retentive-0-0 {
+                compatible = "riscv,idle-state";
+                riscv,sbi-suspend-param = <0x10000000>;
+                entry-latency-us = <20>;
+                exit-latency-us = <40>;
+                min-residency-us = <80>;
+            };
+
+            CPU_NONRET_0_0: cpu-nonretentive-0-0 {
+                compatible = "riscv,idle-state";
+                riscv,sbi-suspend-param = <0x90000000>;
+                entry-latency-us = <250>;
+                exit-latency-us = <500>;
+                min-residency-us = <950>;
+            };
+
+            CLUSTER_RET_0: cluster-retentive-0 {
+                compatible = "riscv,idle-state";
+                riscv,sbi-suspend-param = <0x11000000>;
+                local-timer-stop;
+                entry-latency-us = <50>;
+                exit-latency-us = <100>;
+                min-residency-us = <250>;
+                wakeup-latency-us = <130>;
+            };
+
+            CLUSTER_NONRET_0: cluster-nonretentive-0 {
+                compatible = "riscv,idle-state";
+                riscv,sbi-suspend-param = <0x91000000>;
+                local-timer-stop;
+                entry-latency-us = <600>;
+                exit-latency-us = <1100>;
+                min-residency-us = <2700>;
+                wakeup-latency-us = <1500>;
+            };
+
+            CPU_RET_1_0: cpu-retentive-1-0 {
+                compatible = "riscv,idle-state";
+                riscv,sbi-suspend-param = <0x10000010>;
+                entry-latency-us = <20>;
+                exit-latency-us = <40>;
+                min-residency-us = <80>;
+            };
+
+            CPU_NONRET_1_0: cpu-nonretentive-1-0 {
+                compatible = "riscv,idle-state";
+                riscv,sbi-suspend-param = <0x90000010>;
+                entry-latency-us = <250>;
+                exit-latency-us = <500>;
+                min-residency-us = <950>;
+            };
+
+            CLUSTER_RET_1: cluster-retentive-1 {
+                compatible = "riscv,idle-state";
+                riscv,sbi-suspend-param = <0x11000010>;
+                local-timer-stop;
+                entry-latency-us = <50>;
+                exit-latency-us = <100>;
+                min-residency-us = <250>;
+                wakeup-latency-us = <130>;
+            };
+
+            CLUSTER_NONRET_1: cluster-nonretentive-1 {
+                compatible = "riscv,idle-state";
+                riscv,sbi-suspend-param = <0x91000010>;
+                local-timer-stop;
+                entry-latency-us = <600>;
+                exit-latency-us = <1100>;
+                min-residency-us = <2700>;
+                wakeup-latency-us = <1500>;
+            };
+        };
+    };
+
...

Documentation/devicetree/bindings/riscv/cpus.yaml +6 -1

index aa5fb64d57eb..f62f646bc695 100644
@@ -99,6 +99,12 @@ properties:
       - compatible
       - interrupt-controller
 
+  cpu-idle-states:
+    $ref: '/schemas/types.yaml#/definitions/phandle-array'
+    description: |
+      List of phandles to idle state nodes supported
+      by this hart (see ./idle-states.yaml).
+
 required:
   - riscv,isa
   - interrupt-controller
--

2.25.1

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index d1b87db54d68..6f9a7c89bff9 100644

arch/riscv/configs/rv32_defconfig +1 -1

@@ -20,6 +20,7 @@ CONFIG_SOC_VIRT=y
 CONFIG_ARCH_RV32I=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_PM=y
 CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m
--

2.25.1

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arch/riscv/configs/rv32_defconfig

Quoted 41 lines · Anup Patel

From: Anup Patel <[email protected]>

We enable RISC-V SBI CPU Idle driver for QEMU virt machine to test SBI HSM Supend on QEMU.

Signed-off-by Anup Patel <[email protected]>

Signed-off-by Anup Patel <[email protected]>

---
 arch/riscv/Kconfig.socs           | 3 +++
 arch/riscv/configs/defconfig      | 1 +
 arch/riscv/configs/rv32_defconfig | 1 +
 3 files changed, 5 insertions(+)

arch/riscv/Kconfig.socs +3 -0

index 6ec44a22278a..f4097a815201 100644
@@ -36,6 +36,9 @@ config SOC_VIRT
        select GOLDFISH
        select RTC_DRV_GOLDFISH if RTC_CLASS
        select SIFIVE_PLIC
+       select PM_GENERIC_DOMAINS if PM
+       select PM_GENERIC_DOMAINS_OF if PM && OF
+       select RISCV_SBI_CPUIDLE if CPU_IDLE
        help
          This enables support for QEMU Virt Machine.
 

arch/riscv/configs/defconfig +1 -0

index a5e0482a4969..b8c882b70b02 100644
@@ -20,6 +20,7 @@ CONFIG_SOC_SIFIVE=y
 CONFIG_SOC_VIRT=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_PM=y
 CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m

arch/riscv/configs/rv32_defconfig +0 -0

rv32_defconfig would be removed. I think you could delete this part.
https://lore.kernel.org/linux-riscv/20220201150545.1512822-9-guoren at kernel.org/T/#u

I would Cc you in the patch, and you could track the progress.

Quoted 16 lines

index d1b87db54d68..6f9a7c89bff9 100644

arch/riscv/configs/rv32_defconfig +1 -1

@@ -20,6 +20,7 @@ CONFIG_SOC_VIRT=y
 CONFIG_ARCH_RV32I=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_PM=y
 CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m
--

2.25.1

Quoted 4 lines

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--
Best Regards
Guo Ren

ML: https://lore.kernel.org/linux-csky/

From: Anup Patel <[email protected]>

We enable RISC-V SBI CPU Idle driver for QEMU virt machine to test SBI HSM Supend on QEMU.

Signed-off-by Anup Patel <[email protected]>

Signed-off-by Anup Patel <[email protected]>

---
 arch/riscv/Kconfig.socs           | 3 +++
 arch/riscv/configs/defconfig      | 1 +
 arch/riscv/configs/rv32_defconfig | 1 +
 3 files changed, 5 insertions(+)

arch/riscv/Kconfig.socs +3 -0

index 6ec44a22278a..f4097a815201 100644
@@ -36,6 +36,9 @@ config SOC_VIRT
        select GOLDFISH
        select RTC_DRV_GOLDFISH if RTC_CLASS
        select SIFIVE_PLIC
+       select PM_GENERIC_DOMAINS if PM
+       select PM_GENERIC_DOMAINS_OF if PM && OF
+       select RISCV_SBI_CPUIDLE if CPU_IDLE
        help
          This enables support for QEMU Virt Machine.
 

arch/riscv/configs/defconfig +1 -0

index a5e0482a4969..b8c882b70b02 100644
@@ -20,6 +20,7 @@ CONFIG_SOC_SIFIVE=y
 CONFIG_SOC_VIRT=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_PM=y
 CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m

arch/riscv/configs/rv32_defconfig +1 -1

index d1b87db54d68..6f9a7c89bff9 100644
@@ -20,6 +20,7 @@ CONFIG_SOC_VIRT=y
 CONFIG_ARCH_RV32I=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_PM=y
 CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m
--

2.25.1

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Another question:

Have you put "idle-states {" in qemu's DTS? or how do you test your patches?

Quoted 4 lines · Guo Ren

Another question:

Have you put "idle-states {" in qemu's DTS? or how do you test your patches?

I usually do the following:
1) Dump QEMU virt machine DTB
2) Convert QEMU virt machine DTB into DTS
3) Add "idle-states" in QEMU virt machine DTS
4) Create QEMU virt machine DTB with "idle-states"
5) Use the new QEMU virt machine DTB for testing this series.

Here's one of the DTS files which I used for testing on QEMU virt machine:

/dts-v1/;

/ {
    #address-cells = <0x02>;
    #size-cells = <0x02>;
    compatible = "riscv-virtio";
    model = "riscv-virtio,qemu";

    chosen {
        linux,initrd-end = <0x8855d200>;
        linux,initrd-start = <0x88200000>;
        bootargs = "root=/dev/ram rw console=ttyS0 earlycon";
        stdout-path = "/soc/uart at 10000000";
    };

    memory at 80000000 {
        device_type = "memory";
        reg = <0x00 0x80000000 0x00 0x10000000>;
    };

    cpus {
        #address-cells = <0x01>;
        #size-cells = <0x00>;
        timebase-frequency = <0x989680>;

        cpu at 0 {
            phandle = <0x07>;
            device_type = "cpu";
            reg = <0x00>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_NONRET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x08>;
            };
        };

        cpu at 1 {
            phandle = <0x05>;
            device_type = "cpu";
            reg = <0x01>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_RET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x06>;
            };
        };

        cpu at 2 {
            phandle = <0x03>;
            device_type = "cpu";
            reg = <0x02>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_NONRET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x04>;
            };
        };

        cpu at 3 {
            phandle = <0x01>;
            device_type = "cpu";
            reg = <0x03>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_RET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x02>;
            };
        };

        cpu-map {

            cluster0 {

                core0 {
                    cpu = <0x07>;
                };

                core1 {
                    cpu = <0x05>;
                };

                core2 {
                    cpu = <0x03>;
                };

                core3 {
                    cpu = <0x01>;
                };
            };
        };

        idle-states {
            CPU_RET_DEF: cpu-retentive-default {
                compatible = "riscv,idle-state";
                riscv,sbi-suspend-param = <0x00000000>;
                entry-latency-us = <10>;
                exit-latency-us = <10>;
                min-residency-us = <100>;
            };

            CPU_NONRET_DEF: cpu-nonretentive-default {
                compatible = "riscv,idle-state";
                riscv,sbi-suspend-param = <0x80000000>;
                entry-latency-us = <100>;
                exit-latency-us = <100>;
                min-residency-us = <1000>;
            };
        };
    };

    soc {
        #address-cells = <0x02>;
        #size-cells = <0x02>;
        compatible = "simple-bus";
        ranges;

        flash at 20000000 {
            bank-width = <0x04>;
            reg = <0x00 0x20000000 0x00 0x2000000 0x00 0x22000000 0x00
0x2000000>;
            compatible = "cfi-flash";
        };

        rtc at 101000 {
            interrupts = <0x0b>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x101000 0x00 0x1000>;
            compatible = "google,goldfish-rtc";
        };

        uart at 10000000 {
            interrupts = <0x0a>;
            interrupt-parent = <0x09>;
            clock-frequency = <0x384000>;
            reg = <0x00 0x10000000 0x00 0x100>;
            compatible = "ns16550a";
        };

        poweroff {
            value = <0x5555>;
            offset = <0x00>;
            regmap = <0x0a>;
            compatible = "syscon-poweroff";
        };

        reboot {
            value = <0x7777>;
            offset = <0x00>;
            regmap = <0x0a>;
            compatible = "syscon-reboot";
        };

        test at 100000 {
            phandle = <0x0a>;
            reg = <0x00 0x100000 0x00 0x1000>;
            compatible = "sifive,test1\0sifive,test0\0syscon";
        };

        pci at 30000000 {
            interrupt-map-mask = <0x1800 0x00 0x00 0x07>;
            interrupt-map = <0x00 0x00 0x00 0x01 0x09 0x20 0x00 0x00

0x00 0x02 0x09 0x21 0x00 0x00 0x00 0x03 0x09 0x22 0x00 0x00 0x00 0x04 0x09 0x23 0x800 0x00 0x00 0x01 0x09 0x21 0x800 0x00 0x00 0x02 0x09 0x22 0x800 0x00 0x00 0x03 0x09 0x23 0x800 0x00 0x00 0x04 0x09 0x20 0x1000 0x00 0x00 0x01 0x09 0x22 0x1000 0x00 0x00 0x02 0x09 0x23 0x1000 0x00 0x00 0x03 0x09 0x20 0x1000 0x00 0x00 0x04 0x09 0x21 0x1800 0x00 0x00 0x01 0x09 0x23 0x1800 0x00 0x00 0x02 0x09 0x20 0x1800 0x00 0x00

0x03 0x09 0x21 0x1800 0x00 0x00 0x04 0x09 0x22>;
            ranges = <0x1000000 0x00 0x00 0x00 0x3000000 0x00 0x10000
0x2000000 0x00 0x40000000 0x00 0x40000000 0x00 0x40000000>;
            reg = <0x00 0x30000000 0x00 0x10000000>;
            dma-coherent;
            bus-range = <0x00 0xff>;
            linux,pci-domain = <0x00>;
            device_type = "pci";
            compatible = "pci-host-ecam-generic";
            #size-cells = <0x02>;
            #interrupt-cells = <0x01>;
            #address-cells = <0x03>;
        };

        virtio_mmio at 10008000 {
            interrupts = <0x08>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10008000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10007000 {
            interrupts = <0x07>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10007000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10006000 {
            interrupts = <0x06>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10006000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10005000 {
            interrupts = <0x05>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10005000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10004000 {
            interrupts = <0x04>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10004000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10003000 {
            interrupts = <0x03>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10003000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10002000 {
            interrupts = <0x02>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10002000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10001000 {
            interrupts = <0x01>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10001000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        plic at c000000 {
            phandle = <0x09>;
            riscv,ndev = <0x35>;
            reg = <0x00 0xc000000 0x00 0x210000>;
            interrupts-extended = <0x08 0x0b 0x08 0x09 0x06 0x0b 0x06
0x09 0x04 0x0b 0x04 0x09 0x02 0x0b 0x02 0x09>;
            interrupt-controller;
            compatible = "riscv,plic0";
            #interrupt-cells = <0x01>;
            #address-cells = <0x00>;
        };

        clint at 2000000 {
            interrupts-extended = <0x08 0x03 0x08 0x07 0x06 0x03 0x06
0x07 0x04 0x03 0x04 0x07 0x02 0x03 0x02 0x07>;
            reg = <0x00 0x2000000 0x00 0x10000>;
            compatible = "riscv,clint0";
        };
    };
};

Regards,
Anup

Quoted 293 lines · Anup Patel

Quoted 4 lines · Guo Ren

Another question:

Have you put "idle-states {" in qemu's DTS? or how do you test your patches?

I usually do the following:
1) Dump QEMU virt machine DTB
2) Convert QEMU virt machine DTB into DTS
3) Add "idle-states" in QEMU virt machine DTS
4) Create QEMU virt machine DTB with "idle-states"
5) Use the new QEMU virt machine DTB for testing this series.

Here's one of the DTS files which I used for testing on QEMU virt machine:

/dts-v1/;

/ {
    #address-cells = <0x02>;
    #size-cells = <0x02>;
    compatible = "riscv-virtio";
    model = "riscv-virtio,qemu";

    chosen {
        linux,initrd-end = <0x8855d200>;
        linux,initrd-start = <0x88200000>;
        bootargs = "root=/dev/ram rw console=ttyS0 earlycon";
        stdout-path = "/soc/uart at 10000000";
    };

    memory at 80000000 {
        device_type = "memory";
        reg = <0x00 0x80000000 0x00 0x10000000>;
    };

    cpus {
        #address-cells = <0x01>;
        #size-cells = <0x00>;
        timebase-frequency = <0x989680>;

        cpu at 0 {
            phandle = <0x07>;
            device_type = "cpu";
            reg = <0x00>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_NONRET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x08>;
            };
        };

        cpu at 1 {
            phandle = <0x05>;
            device_type = "cpu";
            reg = <0x01>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_RET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x06>;
            };
        };

        cpu at 2 {
            phandle = <0x03>;
            device_type = "cpu";
            reg = <0x02>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_NONRET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x04>;
            };
        };

        cpu at 3 {
            phandle = <0x01>;
            device_type = "cpu";
            reg = <0x03>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_RET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x02>;
            };
        };

        cpu-map {

            cluster0 {

                core0 {
                    cpu = <0x07>;
                };

                core1 {
                    cpu = <0x05>;
                };

                core2 {
                    cpu = <0x03>;
                };

                core3 {
                    cpu = <0x01>;
                };
            };
        };

        idle-states {
            CPU_RET_DEF: cpu-retentive-default {
                compatible = "riscv,idle-state";
                riscv,sbi-suspend-param = <0x00000000>;
                entry-latency-us = <10>;
                exit-latency-us = <10>;
                min-residency-us = <100>;
            };

            CPU_NONRET_DEF: cpu-nonretentive-default {
                compatible = "riscv,idle-state";
                riscv,sbi-suspend-param = <0x80000000>;
                entry-latency-us = <100>;
                exit-latency-us = <100>;
                min-residency-us = <1000>;
            };
        };
    };

    soc {
        #address-cells = <0x02>;
        #size-cells = <0x02>;
        compatible = "simple-bus";
        ranges;

        flash at 20000000 {
            bank-width = <0x04>;
            reg = <0x00 0x20000000 0x00 0x2000000 0x00 0x22000000 0x00
0x2000000>;
            compatible = "cfi-flash";
        };

        rtc at 101000 {
            interrupts = <0x0b>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x101000 0x00 0x1000>;
            compatible = "google,goldfish-rtc";
        };

        uart at 10000000 {
            interrupts = <0x0a>;
            interrupt-parent = <0x09>;
            clock-frequency = <0x384000>;
            reg = <0x00 0x10000000 0x00 0x100>;
            compatible = "ns16550a";
        };

        poweroff {
            value = <0x5555>;
            offset = <0x00>;
            regmap = <0x0a>;
            compatible = "syscon-poweroff";
        };

        reboot {
            value = <0x7777>;
            offset = <0x00>;
            regmap = <0x0a>;
            compatible = "syscon-reboot";
        };

        test at 100000 {
            phandle = <0x0a>;
            reg = <0x00 0x100000 0x00 0x1000>;
            compatible = "sifive,test1\0sifive,test0\0syscon";
        };

        pci at 30000000 {
            interrupt-map-mask = <0x1800 0x00 0x00 0x07>;
            interrupt-map = <0x00 0x00 0x00 0x01 0x09 0x20 0x00 0x00

0x00 0x02 0x09 0x21 0x00 0x00 0x00 0x03 0x09 0x22 0x00 0x00 0x00 0x04 0x09 0x23 0x800 0x00 0x00 0x01 0x09 0x21 0x800 0x00 0x00 0x02 0x09 0x22 0x800 0x00 0x00 0x03 0x09 0x23 0x800 0x00 0x00 0x04 0x09 0x20 0x1000 0x00 0x00 0x01 0x09 0x22 0x1000 0x00 0x00 0x02 0x09 0x23 0x1000 0x00 0x00 0x03 0x09 0x20 0x1000 0x00 0x00 0x04 0x09 0x21 0x1800 0x00 0x00 0x01 0x09 0x23 0x1800 0x00 0x00 0x02 0x09 0x20 0x1800 0x00 0x00

0x03 0x09 0x21 0x1800 0x00 0x00 0x04 0x09 0x22>;
            ranges = <0x1000000 0x00 0x00 0x00 0x3000000 0x00 0x10000
0x2000000 0x00 0x40000000 0x00 0x40000000 0x00 0x40000000>;
            reg = <0x00 0x30000000 0x00 0x10000000>;
            dma-coherent;
            bus-range = <0x00 0xff>;
            linux,pci-domain = <0x00>;
            device_type = "pci";
            compatible = "pci-host-ecam-generic";
            #size-cells = <0x02>;
            #interrupt-cells = <0x01>;
            #address-cells = <0x03>;
        };

        virtio_mmio at 10008000 {
            interrupts = <0x08>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10008000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10007000 {
            interrupts = <0x07>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10007000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10006000 {
            interrupts = <0x06>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10006000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10005000 {
            interrupts = <0x05>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10005000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10004000 {
            interrupts = <0x04>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10004000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10003000 {
            interrupts = <0x03>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10003000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10002000 {
            interrupts = <0x02>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10002000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10001000 {
            interrupts = <0x01>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10001000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        plic at c000000 {
            phandle = <0x09>;
            riscv,ndev = <0x35>;
            reg = <0x00 0xc000000 0x00 0x210000>;
            interrupts-extended = <0x08 0x0b 0x08 0x09 0x06 0x0b 0x06
0x09 0x04 0x0b 0x04 0x09 0x02 0x0b 0x02 0x09>;
            interrupt-controller;
            compatible = "riscv,plic0";
            #interrupt-cells = <0x01>;
            #address-cells = <0x00>;
        };

Quoted 8 lines

        clint at 2000000 {
            interrupts-extended = <0x08 0x03 0x08 0x07 0x06 0x03 0x06
0x07 0x04 0x03 0x04 0x07 0x02 0x03 0x02 0x07>;
            reg = <0x00 0x2000000 0x00 0x10000>;
            compatible = "riscv,clint0";
        };
    };
};

Thx Anup, but it still couldn't work for testing suspend.

# echo mem > /sys/power/state
sh: write error: Function not implemented

Why there is no ARCH_SUSPEND_POSSIBLE in the patch series?

ref arm64's:
commit 166936bace056dfc11452d794209f39a5e9b0fb4

Author: Lorenzo Pieralisi <[email protected]>
Date:   Thu Nov 7 18:37:14 2013 +0000

arm64: kernel: add PM build infrastructure

This patch adds the required makefile and kconfig entries to enable PM for arm64 systems.

The kernel relies on the cpu_{suspend}/{resume} infrastructure to properly save the context for a CPU and put it to sleep, hence this patch adds the config option required to enable cpu_{suspend}/{resume} API.

In order to rely on the CPU PM implementation for saving and restoring of CPU subsystems like GIC and PMU, the arch Kconfig must be also augmented to select the CONFIG_CPU_PM option when SUSPEND or CPU_IDLE kernel implementations are selected.

Quoted 3 lines

Regards,
Anup

--
Best Regards
Guo Ren

ML: https://lore.kernel.org/linux-csky/

Quoted 306 lines · Guo Ren

Quoted 293 lines · Anup Patel

Quoted 4 lines · Guo Ren

Another question:

Have you put "idle-states {" in qemu's DTS? or how do you test your patches?

I usually do the following:
1) Dump QEMU virt machine DTB
2) Convert QEMU virt machine DTB into DTS
3) Add "idle-states" in QEMU virt machine DTS
4) Create QEMU virt machine DTB with "idle-states"
5) Use the new QEMU virt machine DTB for testing this series.

Here's one of the DTS files which I used for testing on QEMU virt machine:

/dts-v1/;

/ {
    #address-cells = <0x02>;
    #size-cells = <0x02>;
    compatible = "riscv-virtio";
    model = "riscv-virtio,qemu";

    chosen {
        linux,initrd-end = <0x8855d200>;
        linux,initrd-start = <0x88200000>;
        bootargs = "root=/dev/ram rw console=ttyS0 earlycon";
        stdout-path = "/soc/uart at 10000000";
    };

    memory at 80000000 {
        device_type = "memory";
        reg = <0x00 0x80000000 0x00 0x10000000>;
    };

    cpus {
        #address-cells = <0x01>;
        #size-cells = <0x00>;
        timebase-frequency = <0x989680>;

        cpu at 0 {
            phandle = <0x07>;
            device_type = "cpu";
            reg = <0x00>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_NONRET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x08>;
            };
        };

        cpu at 1 {
            phandle = <0x05>;
            device_type = "cpu";
            reg = <0x01>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_RET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x06>;
            };
        };

        cpu at 2 {
            phandle = <0x03>;
            device_type = "cpu";
            reg = <0x02>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_NONRET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x04>;
            };
        };

        cpu at 3 {
            phandle = <0x01>;
            device_type = "cpu";
            reg = <0x03>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_RET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x02>;
            };
        };

        cpu-map {

            cluster0 {

                core0 {
                    cpu = <0x07>;
                };

                core1 {
                    cpu = <0x05>;
                };

                core2 {
                    cpu = <0x03>;
                };

                core3 {
                    cpu = <0x01>;
                };
            };
        };

        idle-states {
            CPU_RET_DEF: cpu-retentive-default {
                compatible = "riscv,idle-state";
                riscv,sbi-suspend-param = <0x00000000>;
                entry-latency-us = <10>;
                exit-latency-us = <10>;
                min-residency-us = <100>;
            };

            CPU_NONRET_DEF: cpu-nonretentive-default {
                compatible = "riscv,idle-state";
                riscv,sbi-suspend-param = <0x80000000>;
                entry-latency-us = <100>;
                exit-latency-us = <100>;
                min-residency-us = <1000>;
            };
        };
    };

    soc {
        #address-cells = <0x02>;
        #size-cells = <0x02>;
        compatible = "simple-bus";
        ranges;

        flash at 20000000 {
            bank-width = <0x04>;
            reg = <0x00 0x20000000 0x00 0x2000000 0x00 0x22000000 0x00
0x2000000>;
            compatible = "cfi-flash";
        };

        rtc at 101000 {
            interrupts = <0x0b>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x101000 0x00 0x1000>;
            compatible = "google,goldfish-rtc";
        };

        uart at 10000000 {
            interrupts = <0x0a>;
            interrupt-parent = <0x09>;
            clock-frequency = <0x384000>;
            reg = <0x00 0x10000000 0x00 0x100>;
            compatible = "ns16550a";
        };

        poweroff {
            value = <0x5555>;
            offset = <0x00>;
            regmap = <0x0a>;
            compatible = "syscon-poweroff";
        };

        reboot {
            value = <0x7777>;
            offset = <0x00>;
            regmap = <0x0a>;
            compatible = "syscon-reboot";
        };

        test at 100000 {
            phandle = <0x0a>;
            reg = <0x00 0x100000 0x00 0x1000>;
            compatible = "sifive,test1\0sifive,test0\0syscon";
        };

        pci at 30000000 {
            interrupt-map-mask = <0x1800 0x00 0x00 0x07>;
            interrupt-map = <0x00 0x00 0x00 0x01 0x09 0x20 0x00 0x00

0x00 0x02 0x09 0x21 0x00 0x00 0x00 0x03 0x09 0x22 0x00 0x00 0x00 0x04 0x09 0x23 0x800 0x00 0x00 0x01 0x09 0x21 0x800 0x00 0x00 0x02 0x09 0x22 0x800 0x00 0x00 0x03 0x09 0x23 0x800 0x00 0x00 0x04 0x09 0x20 0x1000 0x00 0x00 0x01 0x09 0x22 0x1000 0x00 0x00 0x02 0x09 0x23 0x1000 0x00 0x00 0x03 0x09 0x20 0x1000 0x00 0x00 0x04 0x09 0x21 0x1800 0x00 0x00 0x01 0x09 0x23 0x1800 0x00 0x00 0x02 0x09 0x20 0x1800 0x00 0x00

0x03 0x09 0x21 0x1800 0x00 0x00 0x04 0x09 0x22>;
            ranges = <0x1000000 0x00 0x00 0x00 0x3000000 0x00 0x10000
0x2000000 0x00 0x40000000 0x00 0x40000000 0x00 0x40000000>;
            reg = <0x00 0x30000000 0x00 0x10000000>;
            dma-coherent;
            bus-range = <0x00 0xff>;
            linux,pci-domain = <0x00>;
            device_type = "pci";
            compatible = "pci-host-ecam-generic";
            #size-cells = <0x02>;
            #interrupt-cells = <0x01>;
            #address-cells = <0x03>;
        };

        virtio_mmio at 10008000 {
            interrupts = <0x08>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10008000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10007000 {
            interrupts = <0x07>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10007000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10006000 {
            interrupts = <0x06>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10006000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10005000 {
            interrupts = <0x05>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10005000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10004000 {
            interrupts = <0x04>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10004000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10003000 {
            interrupts = <0x03>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10003000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10002000 {
            interrupts = <0x02>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10002000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10001000 {
            interrupts = <0x01>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10001000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        plic at c000000 {
            phandle = <0x09>;
            riscv,ndev = <0x35>;
            reg = <0x00 0xc000000 0x00 0x210000>;
            interrupts-extended = <0x08 0x0b 0x08 0x09 0x06 0x0b 0x06
0x09 0x04 0x0b 0x04 0x09 0x02 0x0b 0x02 0x09>;
            interrupt-controller;
            compatible = "riscv,plic0";
            #interrupt-cells = <0x01>;
            #address-cells = <0x00>;
        };

Quoted 8 lines

        clint at 2000000 {
            interrupts-extended = <0x08 0x03 0x08 0x07 0x06 0x03 0x06
0x07 0x04 0x03 0x04 0x07 0x02 0x03 0x02 0x07>;
            reg = <0x00 0x2000000 0x00 0x10000>;
            compatible = "riscv,clint0";
        };
    };
};

Thx Anup, but it still couldn't work for testing suspend.

Quoted 4 lines

# echo mem > /sys/power/state
sh: write error: Function not implemented

Why there is no ARCH_SUSPEND_POSSIBLE in the patch series?

You are referring to system-level suspend to RAM support whereas this series adds CPU idle power management support.

Adding system-level suspend to RAM will be a separate series and it will re-use the non-retentive suspend infrastructure added by this series.

Regards,
Anup

Quoted 32 lines

ref arm64's:
commit 166936bace056dfc11452d794209f39a5e9b0fb4

Author: Lorenzo Pieralisi <[email protected]>
Date:   Thu Nov 7 18:37:14 2013 +0000

arm64: kernel: add PM build infrastructure

This patch adds the required makefile and kconfig entries to enable PM for arm64 systems.

The kernel relies on the cpu_{suspend}/{resume} infrastructure to properly save the context for a CPU and put it to sleep, hence this patch adds the config option required to enable cpu_{suspend}/{resume} API.

In order to rely on the CPU PM implementation for saving and restoring of CPU subsystems like GIC and PMU, the arch Kconfig must be also augmented to select the CONFIG_CPU_PM option when SUSPEND or CPU_IDLE kernel implementations are selected.

Quoted 3 lines

Regards,
Anup

--
Best Regards
Guo Ren

ML: https://lore.kernel.org/linux-csky/

Quoted 308 lines · Anup Patel

Quoted 306 lines · Guo Ren

Quoted 293 lines · Anup Patel

Quoted 4 lines · Guo Ren

Another question:

Have you put "idle-states {" in qemu's DTS? or how do you test your patches?

I usually do the following:
1) Dump QEMU virt machine DTB
2) Convert QEMU virt machine DTB into DTS
3) Add "idle-states" in QEMU virt machine DTS
4) Create QEMU virt machine DTB with "idle-states"
5) Use the new QEMU virt machine DTB for testing this series.

Here's one of the DTS files which I used for testing on QEMU virt machine:

/dts-v1/;

/ {
    #address-cells = <0x02>;
    #size-cells = <0x02>;
    compatible = "riscv-virtio";
    model = "riscv-virtio,qemu";

    chosen {
        linux,initrd-end = <0x8855d200>;
        linux,initrd-start = <0x88200000>;
        bootargs = "root=/dev/ram rw console=ttyS0 earlycon";
        stdout-path = "/soc/uart at 10000000";
    };

    memory at 80000000 {
        device_type = "memory";
        reg = <0x00 0x80000000 0x00 0x10000000>;
    };

    cpus {
        #address-cells = <0x01>;
        #size-cells = <0x00>;
        timebase-frequency = <0x989680>;

        cpu at 0 {
            phandle = <0x07>;
            device_type = "cpu";
            reg = <0x00>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_NONRET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x08>;
            };
        };

        cpu at 1 {
            phandle = <0x05>;
            device_type = "cpu";
            reg = <0x01>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_RET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x06>;
            };
        };

        cpu at 2 {
            phandle = <0x03>;
            device_type = "cpu";
            reg = <0x02>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_NONRET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x04>;
            };
        };

        cpu at 3 {
            phandle = <0x01>;
            device_type = "cpu";
            reg = <0x03>;
            status = "okay";
            compatible = "riscv";
            riscv,isa = "rv64imafdcsu";
            mmu-type = "riscv,sv48";
            cpu-idle-states = <&CPU_RET_DEF>;

            interrupt-controller {
                #interrupt-cells = <0x01>;
                interrupt-controller;
                compatible = "riscv,cpu-intc";
                phandle = <0x02>;
            };
        };

        cpu-map {

            cluster0 {

                core0 {
                    cpu = <0x07>;
                };

                core1 {
                    cpu = <0x05>;
                };

                core2 {
                    cpu = <0x03>;
                };

                core3 {
                    cpu = <0x01>;
                };
            };
        };

        idle-states {
            CPU_RET_DEF: cpu-retentive-default {
                compatible = "riscv,idle-state";
                riscv,sbi-suspend-param = <0x00000000>;
                entry-latency-us = <10>;
                exit-latency-us = <10>;
                min-residency-us = <100>;
            };

            CPU_NONRET_DEF: cpu-nonretentive-default {
                compatible = "riscv,idle-state";
                riscv,sbi-suspend-param = <0x80000000>;
                entry-latency-us = <100>;
                exit-latency-us = <100>;
                min-residency-us = <1000>;
            };
        };
    };

    soc {
        #address-cells = <0x02>;
        #size-cells = <0x02>;
        compatible = "simple-bus";
        ranges;

        flash at 20000000 {
            bank-width = <0x04>;
            reg = <0x00 0x20000000 0x00 0x2000000 0x00 0x22000000 0x00
0x2000000>;
            compatible = "cfi-flash";
        };

        rtc at 101000 {
            interrupts = <0x0b>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x101000 0x00 0x1000>;
            compatible = "google,goldfish-rtc";
        };

        uart at 10000000 {
            interrupts = <0x0a>;
            interrupt-parent = <0x09>;
            clock-frequency = <0x384000>;
            reg = <0x00 0x10000000 0x00 0x100>;
            compatible = "ns16550a";
        };

        poweroff {
            value = <0x5555>;
            offset = <0x00>;
            regmap = <0x0a>;
            compatible = "syscon-poweroff";
        };

        reboot {
            value = <0x7777>;
            offset = <0x00>;
            regmap = <0x0a>;
            compatible = "syscon-reboot";
        };

        test at 100000 {
            phandle = <0x0a>;
            reg = <0x00 0x100000 0x00 0x1000>;
            compatible = "sifive,test1\0sifive,test0\0syscon";
        };

        pci at 30000000 {
            interrupt-map-mask = <0x1800 0x00 0x00 0x07>;
            interrupt-map = <0x00 0x00 0x00 0x01 0x09 0x20 0x00 0x00

0x00 0x02 0x09 0x21 0x00 0x00 0x00 0x03 0x09 0x22 0x00 0x00 0x00 0x04 0x09 0x23 0x800 0x00 0x00 0x01 0x09 0x21 0x800 0x00 0x00 0x02 0x09 0x22 0x800 0x00 0x00 0x03 0x09 0x23 0x800 0x00 0x00 0x04 0x09 0x20 0x1000 0x00 0x00 0x01 0x09 0x22 0x1000 0x00 0x00 0x02 0x09 0x23 0x1000 0x00 0x00 0x03 0x09 0x20 0x1000 0x00 0x00 0x04 0x09 0x21 0x1800 0x00 0x00 0x01 0x09 0x23 0x1800 0x00 0x00 0x02 0x09 0x20 0x1800 0x00 0x00

0x03 0x09 0x21 0x1800 0x00 0x00 0x04 0x09 0x22>;
            ranges = <0x1000000 0x00 0x00 0x00 0x3000000 0x00 0x10000
0x2000000 0x00 0x40000000 0x00 0x40000000 0x00 0x40000000>;
            reg = <0x00 0x30000000 0x00 0x10000000>;
            dma-coherent;
            bus-range = <0x00 0xff>;
            linux,pci-domain = <0x00>;
            device_type = "pci";
            compatible = "pci-host-ecam-generic";
            #size-cells = <0x02>;
            #interrupt-cells = <0x01>;
            #address-cells = <0x03>;
        };

        virtio_mmio at 10008000 {
            interrupts = <0x08>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10008000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10007000 {
            interrupts = <0x07>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10007000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10006000 {
            interrupts = <0x06>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10006000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10005000 {
            interrupts = <0x05>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10005000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10004000 {
            interrupts = <0x04>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10004000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10003000 {
            interrupts = <0x03>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10003000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10002000 {
            interrupts = <0x02>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10002000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        virtio_mmio at 10001000 {
            interrupts = <0x01>;
            interrupt-parent = <0x09>;
            reg = <0x00 0x10001000 0x00 0x1000>;
            compatible = "virtio,mmio";
        };

        plic at c000000 {
            phandle = <0x09>;
            riscv,ndev = <0x35>;
            reg = <0x00 0xc000000 0x00 0x210000>;
            interrupts-extended = <0x08 0x0b 0x08 0x09 0x06 0x0b 0x06
0x09 0x04 0x0b 0x04 0x09 0x02 0x0b 0x02 0x09>;
            interrupt-controller;
            compatible = "riscv,plic0";
            #interrupt-cells = <0x01>;
            #address-cells = <0x00>;
        };

Quoted 8 lines

        clint at 2000000 {
            interrupts-extended = <0x08 0x03 0x08 0x07 0x06 0x03 0x06
0x07 0x04 0x03 0x04 0x07 0x02 0x03 0x02 0x07>;
            reg = <0x00 0x2000000 0x00 0x10000>;
            compatible = "riscv,clint0";
        };
    };
};

Thx Anup, but it still couldn't work for testing suspend.

Quoted 7 lines

Quoted 4 lines

# echo mem > /sys/power/state
sh: write error: Function not implemented

Why there is no ARCH_SUSPEND_POSSIBLE in the patch series?

You are referring to system-level suspend to RAM support whereas this series adds CPU idle power management support.

Right.

Quoted 4 lines

Adding system-level suspend to RAM will be a separate series and it will re-use the non-retentive suspend infrastructure added by this series.

Do you have the plan for the feature of SUSPEND? I think you've done the core part by this series.

In the end, thx for the work :)

Quoted 36 lines

Regards,
Anup

Quoted 32 lines

ref arm64's:
commit 166936bace056dfc11452d794209f39a5e9b0fb4

Author: Lorenzo Pieralisi <[email protected]>
Date:   Thu Nov 7 18:37:14 2013 +0000

arm64: kernel: add PM build infrastructure

This patch adds the required makefile and kconfig entries to enable PM for arm64 systems.

The kernel relies on the cpu_{suspend}/{resume} infrastructure to properly save the context for a CPU and put it to sleep, hence this patch adds the config option required to enable cpu_{suspend}/{resume} API.

In order to rely on the CPU PM implementation for saving and restoring of CPU subsystems like GIC and PMU, the arch Kconfig must be also augmented to select the CONFIG_CPU_PM option when SUSPEND or CPU_IDLE kernel implementations are selected.

Quoted 3 lines

Regards,
Anup

--
Best Regards
Guo Ren

ML: https://lore.kernel.org/linux-csky/

--
Best Regards
Guo Ren

ML: https://lore.kernel.org/linux-csky/