RISC-V CPU Idle Support

From: Anup Patel <[email protected]>

This series adds RISC-V CPU Idle support using SBI HSM suspend function. The RISC-V SBI CPU idle driver added by this series is highly inspired from the ARM PSCI CPU idle driver.

At high-level, this series includes the following changes:
1) Preparatory arch/riscv patches (Patches 1 to 3)
2) Defines for RISC-V SBI HSM suspend (Patch 4)
3) Preparatory patch to share code between RISC-V SBI CPU idle driver and ARM PSCI CPU idle driver (Patch 5)
4) RISC-V SBI CPU idle driver and related DT bindings (Patches 6 to 7)

These patches can be found in riscv_sbi_hsm_suspend_v11 branch of
https://github.com/avpatel/linux.git

Special thanks Sandeep Tripathy for providing early feeback on SBI HSM support in all above projects (RISC-V SBI specification, OpenSBI, and Linux RISC-V).

Changes since v10:
- Rebased on Linux-5.17-rc3
- Typo fix in commit description of PATCH6

Changes since v9:
- Rebased on Linux-5.17-rc1

Changes since v8:
- Rebased on Linux-5.15-rc5
- Fixed DT schema check errors in PATCH7

Changes since v7:
- Rebased on Linux-5.15-rc3
- Renamed cpuidle-sbi.c to cpuidle-riscv-sbi.c in PATCH6

Changes since v6:
- Fixed error reported by "make DT_CHECKER_FLAGS=-m dt_binding_check"

Changes since v5:
- Rebased on Linux-5.13-rc5
- Removed unnecessary exports from PATCH5
- Removed stray ";" from PATCH5
- Moved sbi_cpuidle_pd_power_off() under "#ifdef CONFIG_DT_IDLE_GENPD" in PATCH6

Changes since v4:
- Rebased on Linux-5.13-rc2
- Renamed all dt_idle_genpd functions to have "dt_idle_" prefix
- Added MAINTAINERS file entry for dt_idle_genpd

Changes since v3:
- Rebased on Linux-5.13-rc2
- Fixed __cpu_resume_enter() which was broken due to XIP kernel support
- Removed "struct dt_idle_genpd_ops" abstraction which simplifies code sharing between ARM PSCI and RISC-V SBI drivers in PATCH5

Changes since v2:
- Rebased on Linux-5.12-rc3
- Updated PATCH7 to add common DT bindings for both ARM and RISC-V idle states
- Added "additionalProperties = false" for both idle-states node and child nodes in PATCH7

Changes since v1:
- Fixex minor typo in PATCH1
- Use just "idle-states" as DT node name for CPU idle states
- Added documentation for "cpu-idle-states" DT property in devicetree/bindings/riscv/cpus.yaml
- Added documentation for "riscv,sbi-suspend-param" DT property in devicetree/bindings/riscv/idle-states.yaml

Anup Patel (8):
RISC-V: Enable CPU_IDLE drivers
RISC-V: Rename relocate() and make it global
RISC-V: Add arch functions for non-retentive suspend entry/exit
RISC-V: Add SBI HSM suspend related defines
cpuidle: Factor-out power domain related code from PSCI domain driver
cpuidle: Add RISC-V SBI CPU idle driver
dt-bindings: Add common bindings for ARM and RISC-V idle states
RISC-V: Enable RISC-V SBI CPU Idle driver for QEMU virt machine

 .../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 +
 MAINTAINERS                                   |  14 +
 arch/riscv/Kconfig                            |   7 +
 arch/riscv/Kconfig.socs                       |   3 +
 arch/riscv/configs/defconfig                  |   2 +
 arch/riscv/configs/rv32_defconfig             |   2 +
 arch/riscv/include/asm/asm.h                  |  27 +
 arch/riscv/include/asm/cpuidle.h              |  24 +
 arch/riscv/include/asm/sbi.h                  |  27 +-
 arch/riscv/include/asm/suspend.h              |  36 +
 arch/riscv/kernel/Makefile                    |   2 +
 arch/riscv/kernel/asm-offsets.c               |   3 +
 arch/riscv/kernel/cpu_ops_sbi.c               |   2 +-
 arch/riscv/kernel/head.S                      |  28 +-
 arch/riscv/kernel/process.c                   |   3 +-
 arch/riscv/kernel/suspend.c                   |  87 +++
 arch/riscv/kernel/suspend_entry.S             | 124 ++++
 arch/riscv/kvm/vcpu_sbi_hsm.c                 |   4 +-
 drivers/cpuidle/Kconfig                       |   9 +
 drivers/cpuidle/Kconfig.arm                   |   1 +
 drivers/cpuidle/Kconfig.riscv                 |  15 +
 drivers/cpuidle/Makefile                      |   5 +
 drivers/cpuidle/cpuidle-psci-domain.c         | 138 +---
 drivers/cpuidle/cpuidle-psci.h                |  15 +-
 drivers/cpuidle/cpuidle-riscv-sbi.c           | 627 ++++++++++++++++++
 drivers/cpuidle/dt_idle_genpd.c               | 178 +++++
 drivers/cpuidle/dt_idle_genpd.h               |  50 ++
 30 files changed, 1484 insertions(+), 187 deletions(-)
 rename Documentation/devicetree/bindings/{arm => cpu}/idle-states.yaml (74%)
 create mode 100644 arch/riscv/include/asm/cpuidle.h
 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
 create mode 100644 drivers/cpuidle/Kconfig.riscv
 create mode 100644 drivers/cpuidle/cpuidle-riscv-sbi.c
 create mode 100644 drivers/cpuidle/dt_idle_genpd.c
 create mode 100644 drivers/cpuidle/dt_idle_genpd.h

2.25.1