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

[Anup Patel]

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 shared 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_v1 branch at
https://github.com/avpatel/linux

The proposed SBI HSM suspend definition can be found in hsm_suspend_v3
branch at https://github.com/avpatel/riscv-sbi-doc

The OpenSBI implementation of SBI HSM suspend function can be found
in hsm_suspend_v1 branch at https://github.com/avpatel/opensbi

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).

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 bindings documentation for RISC-V idle states
  RISC-V: Enable RISC-V SBI CPU Idle driver for QEMU virt machine

 .../bindings/riscv/idle-states.yaml           | 250 +++++++++
 MAINTAINERS                                   |   8 +
 arch/riscv/Kconfig                            |   7 +
 arch/riscv/Kconfig.socs                       |   3 +
 arch/riscv/configs/defconfig                  |   8 +-
 arch/riscv/configs/rv32_defconfig             |   5 +-
 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                      |   7 +-
 arch/riscv/kernel/process.c                   |   3 +-
 arch/riscv/kernel/suspend.c                   |  86 +++
 arch/riscv/kernel/suspend_entry.S             | 116 ++++
 drivers/cpuidle/Kconfig                       |   9 +
 drivers/cpuidle/Kconfig.arm                   |   1 +
 drivers/cpuidle/Kconfig.riscv                 |  15 +
 drivers/cpuidle/Makefile                      |   5 +
 drivers/cpuidle/cpuidle-psci-domain.c         | 244 +--------
 drivers/cpuidle/cpuidle-psci.h                |  15 +-
 drivers/cpuidle/cpuidle-sbi.c                 | 503 ++++++++++++++++++
 ...{cpuidle-psci-domain.c => dt_idle_genpd.c} | 165 ++----
 drivers/cpuidle/dt_idle_genpd.h               |  42 ++
 25 files changed, 1218 insertions(+), 367 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/riscv/idle-states.yaml
 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
 copy drivers/cpuidle/{cpuidle-psci-domain.c => dt_idle_genpd.c} (52%)
 create mode 100644 drivers/cpuidle/dt_idle_genpd.h

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2.25.1