ARM: mach-shmobile: Initial SMP support

ARM: mach-shmobile: Initial SMP support

[PATCH 01/03] ARM: mach-shmobile: SMP base support [PATCH 02/03] ARM: mach-shmobile: Enable SMP support [PATCH 03/03] ARM: mach-shmobile: sh73a0 SMP support

These patches add SMP framework support for R-Mobile and SH-Mobile processors, together with hardware specific SMP support for the sh73a0 processor.

Survives onlining and offlining of secondary processor cores through sysfs. Should compile and boot regardless of CONFIG_SMP, CONFIG_HOTPLUG_CPU and CONFIG_LOCAL_TIMERS.

I suggest that patch 1 and 3 are taken through sh-2.6 and patch 2 goes through the RMK patch tracker.

---
 arch/arm/Kconfig                                       |    3 
 arch/arm/mach-shmobile/Makefile                        |    7 +
 arch/arm/mach-shmobile/headsmp.S                       |   26 ++++
 arch/arm/mach-shmobile/hotplug.c                       |   41 ++++++
 arch/arm/mach-shmobile/include/mach/common.h           |    6 
 arch/arm/mach-shmobile/include/mach/entry-macro-intc.S |    6 
 arch/arm/mach-shmobile/include/mach/smp.h              |   16 ++
 arch/arm/mach-shmobile/localtimer.c                    |   25 ++++
 arch/arm/mach-shmobile/platsmp.c                       |   87 ++++++++++++++
 arch/arm/mach-shmobile/smp-sh73a0.c                    |   98 ++++++++++++++++
 10 files changed, 313 insertions(+), 2 deletions(-)

From: Magnus Damm <[email protected]>

Add SMP base support for R-Mobile / SH-Mobile processors.

This patch contains all base code to support CONFIG_SMP regardless of ARCH_SHMOBILE processor type. Both local timer and CPU hotplug are supported, but no processor specific code is included.

At this point only the default behavior is in place, so a single core will always be used even though CONFIG_SMP is enabled on multicore systems.

The SMP Kconfig entry for arch/arm/Kconfig is excluded from this patch to simplify merging.

---

Future patches may be required to sync up the framework bits with current/upcoming changes in RMKs git repository.

 arch/arm/mach-shmobile/Makefile                        |    6 +
 arch/arm/mach-shmobile/headsmp.S                       |   26 +++++
 arch/arm/mach-shmobile/hotplug.c                       |   41 ++++++++
 arch/arm/mach-shmobile/include/mach/common.h           |    1 
 arch/arm/mach-shmobile/include/mach/entry-macro-intc.S |    6 +
 arch/arm/mach-shmobile/include/mach/smp.h              |   16 +++
 arch/arm/mach-shmobile/localtimer.c                    |   25 +++++
 arch/arm/mach-shmobile/platsmp.c                       |   73 ++++++++++++++++
 8 files changed, 194 insertions(+)

@@ -11,6 +11,11 @@ obj-$(CONFIG_ARCH_SH7377)	+= setup-sh737
 obj-$(CONFIG_ARCH_SH7372)	+= setup-sh7372.o clock-sh7372.o intc-sh7372.o
 obj-$(CONFIG_ARCH_SH73A0)	+= setup-sh73a0.o clock-sh73a0.o
 
+# SMP objects
+smp-y				:= platsmp.o headsmp.o
+smp-$(CONFIG_HOTPLUG_CPU)	+= hotplug.o
+smp-$(CONFIG_LOCAL_TIMERS)	+= localtimer.o
+
 # Pinmux setup
 pfc-y				:=
 pfc-$(CONFIG_ARCH_SH7367)	+= pfc-sh7367.o

@@ -26,4 +31,5 @@ obj-$(CONFIG_MACH_AG5EVM)	+= board-ag5ev
 obj-$(CONFIG_MACH_MACKEREL)	+= board-mackerel.o
 
 # Framework support
+obj-$(CONFIG_SMP)		+= $(smp-y)
 obj-$(CONFIG_GENERIC_GPIO)	+= $(pfc-y)

@@ -0,0 +1,26 @@
+/*
+ * SMP support for R-Mobile / SH-Mobile
+ *
+ * Copyright (C) 2010  Magnus Damm
+ * Copyright (C) 2010  Takashi Yoshii
+ *
+ * Based on vexpress, Copyright (c) 2003 ARM Limited, All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/linkage.h>
+#include <linux/init.h>
+
+	__INIT
+
+/*
+ * Reset vector for secondary CPUs.
+ * This will be mapped at address 0 by SBAR register.
+ * We need _long_ jump to the physical address.
+ */
+	.align  12
+ENTRY(shmobile_secondary_vector)
+	ldr     pc, 1f
+1:	.long   secondary_startup - CONFIG_PAGE_OFFSET + CONFIG_MEMORY_START

@@ -3,6 +3,7 @@
 
 extern struct sys_timer shmobile_timer;
 extern void shmobile_setup_console(void);
+extern void shmobile_secondary_vector(void);
 struct clk;
 extern int clk_init(void);
 

@@ -17,6 +17,12 @@
 #include <mach/hardware.h>
 #include <mach/irqs.h>
 
+	.macro	test_for_ipi, irqnr, irqstat, base, tmp
+	.endm
+
+	.macro	test_for_ltirq, irqnr, irqstat, base, tmp
+	.endm
+
 	.macro  disable_fiq
 	.endm
 

@@ -0,0 +1,16 @@
+#ifndef __MACH_SMP_H
+#define __MACH_SMP_H
+
+#include <asm/hardware/gic.h>
+#include <asm/smp_mpidr.h>
+
+/*
+ * We use IRQ1 as the IPI
+ */
+static inline void smp_cross_call(const struct cpumask *mask)
+{
+#if defined(CONFIG_ARM_GIC)
+	gic_raise_softirq(mask, 1);
+#endif
+}
+#endif

@@ -0,0 +1,25 @@
+/*
+ * SMP support for R-Mobile / SH-Mobile - local timer portion
+ *
+ * Copyright (C) 2010  Magnus Damm
+ *
+ * Based on vexpress, Copyright (C) 2002 ARM Ltd, All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/clockchips.h>
+#include <asm/smp_twd.h>
+#include <asm/localtimer.h>
+
+/*
+ * Setup the local clock events for a CPU.
+ */
+void __cpuinit local_timer_setup(struct clock_event_device *evt)
+{
+	evt->irq = 29;
+	twd_timer_setup(evt);
+}

Sure, good point. This was actually the only part of this series that I wasn't 100% satisfied with.

Will send a patch on top of this series during early next week.

Thanks,

/ magnus

From: Magnus Damm <[email protected]>

Allow SMP to be enabled on R-Mobile / SH-Mobile.

---

May need to be reworked to fit the current state of the tree associated with the RMK patch tracker.

 arch/arm/Kconfig |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -1211,7 +1211,8 @@ config SMP
 	depends on GENERIC_CLOCKEVENTS
 	depends on REALVIEW_EB_ARM11MP || REALVIEW_EB_A9MP || \
 		 MACH_REALVIEW_PB11MP || MACH_REALVIEW_PBX || ARCH_OMAP4 ||\
-		 ARCH_S5PV310 || ARCH_TEGRA || ARCH_U8500 || ARCH_VEXPRESS_CA9X4
+		 ARCH_S5PV310 || ARCH_TEGRA || ARCH_U8500 || ARCH_VEXPRESS_CA9X4 || \
+		 ARCH_SHMOBILE
 	select USE_GENERIC_SMP_HELPERS
 	select HAVE_ARM_SCU
 	help

From: Magnus Damm <[email protected]>

Add SMP support for ag5evm and the sh73a0 processor.

Onlining and offlining works well, but at this point offlined processor cores are not put into sleep mode.

There is no spinlock for syncing the secondary core with the first one in this implementation. The code instead relies on the cpu_online() check in __cpu_up().

---

 arch/arm/mach-shmobile/Makefile              |    1 
 arch/arm/mach-shmobile/include/mach/common.h |    5 +
 arch/arm/mach-shmobile/platsmp.c             |   14 +++
 arch/arm/mach-shmobile/smp-sh73a0.c          |   98 ++++++++++++++++++++++++++
 4 files changed, 117 insertions(+), 1 deletion(-)

@@ -15,6 +15,7 @@ obj-$(CONFIG_ARCH_SH73A0)	+= setup-sh73a
 smp-y				:= platsmp.o headsmp.o
 smp-$(CONFIG_HOTPLUG_CPU)	+= hotplug.o
 smp-$(CONFIG_LOCAL_TIMERS)	+= localtimer.o
+smp-$(CONFIG_ARCH_SH73A0)	+= smp-sh73a0.o
 
 # Pinmux setup
 pfc-y				:=

@@ -38,4 +38,9 @@ extern void sh73a0_pinmux_init(void);
 extern struct clk sh73a0_extal1_clk;
 extern struct clk sh73a0_extal2_clk;
 
+extern unsigned int sh73a0_get_core_count(void);
+extern void sh73a0_secondary_init(unsigned int cpu);
+extern int sh73a0_boot_secondary(unsigned int cpu);
+extern void sh73a0_smp_prepare_cpus(void);
+
 #endif /* __ARCH_MACH_COMMON_H */

@@ -16,25 +16,37 @@
 #include <linux/smp.h>
 #include <linux/io.h>
 #include <asm/localtimer.h>
+#include <asm/mach-types.h>
+#include <mach/common.h>
 
 static unsigned int __init shmobile_smp_get_core_count(void)
 {
+	if (machine_is_ag5evm())
+		return sh73a0_get_core_count();
+
 	return 1;
 }
 
 static void __init shmobile_smp_prepare_cpus(void)
 {
-	/* do nothing for now */
+	if (machine_is_ag5evm())
+		sh73a0_smp_prepare_cpus();
 }
 
 
 void __cpuinit platform_secondary_init(unsigned int cpu)
 {
 	trace_hardirqs_off();
+
+	if (machine_is_ag5evm())
+		sh73a0_secondary_init(cpu);
 }
 
 int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
 {
+	if (machine_is_ag5evm())
+		return sh73a0_boot_secondary(cpu);
+
 	return -ENOSYS;
 }
 

Applied to rmobile/smp, thanks.

There are integration issues with regards to the GIC changes that I'll have to take care of during the merge window regardless, so resolving the CONFIG_SMP thing at that point should be pretty straightforward. My plan is to wait until after Russell merges, merge your stuff on top of that, and then send the updated bits to Linus in one shot.

In order to avoid clashes with -next for now however I won't be merging the topic branch in to my -latest branch. Given that the number of boards in the wild for this at the moment are in the single digits, I'm not too worried about the amount of time these changes spend in -next so long as no regressions are introduced for the other boards.

I've now merged the rmobile/smp branch in to rmobile-latest, which resolves the minor clashes with Russell's merge as well as the entry-macro rework.