[RFC PATCH v4 0/8] RISC-V CPU Idle Support

From: Anup Patel
Date: Mon May 17 2021 - 09:09:45 EST


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_v4 branch at
https://github.com/avpatel/linux

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 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 => cpu}/idle-states.yaml | 228 ++++++-
.../devicetree/bindings/riscv/cpus.yaml | 6 +
MAINTAINERS | 7 +
arch/riscv/Kconfig | 7 +
arch/riscv/Kconfig.socs | 3 +
arch/riscv/configs/defconfig | 13 +-
arch/riscv/configs/rv32_defconfig | 6 +-
arch/riscv/include/asm/asm.h | 17 +
arch/riscv/include/asm/cpuidle.h | 24 +
arch/riscv/include/asm/sbi.h | 27 +-
arch/riscv/include/asm/suspend.h | 35 +
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 | 18 +-
arch/riscv/kernel/process.c | 3 +-
arch/riscv/kernel/suspend.c | 86 +++
arch/riscv/kernel/suspend_entry.S | 123 ++++
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-sbi.c | 625 ++++++++++++++++++
drivers/cpuidle/dt_idle_genpd.c | 182 +++++
drivers/cpuidle/dt_idle_genpd.h | 50 ++
27 files changed, 1467 insertions(+), 183 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-sbi.c
create mode 100644 drivers/cpuidle/dt_idle_genpd.c
create mode 100644 drivers/cpuidle/dt_idle_genpd.h

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2.25.1