[v2,-next,0/3] RISC-V: ACPI: Add LPI support

Message

Sunil V L Jan. 15, 2024, 10:10 a.m. UTC

This series adds support for Low Power Idle (LPI) on ACPI based
platforms. 

LPI is described in the ACPI spec [1]. RISC-V FFH spec required to
enable this is available at [2].

[1] - https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html#lpi-low-power-idle-states 
[2] - https://github.com/riscv-non-isa/riscv-acpi-ffh/releases/download/v/riscv-ffh.pdf

Changes since v1:
	1) Reordered the commits such that the patch which enables
	   ACPI_PROCESSOR is the last one in the series.
	2) Used GENMASK and other changes to address Drew's comments.
	3) Moved common functions required by both DT and ACPI based cpuidle
	   drivers from the DT driver to common arch/riscv/suspend.c.
	4) ACPI cpuidle driver is added under drivers/acpi/riscv
	5) Rebased to latest for-next branch of linux-riscv.

Sunil V L (3):
  cpuidle: RISC-V: Move few functions to arch/riscv
  ACPI: RISC-V: Add LPI driver
  ACPI: Enable ACPI_PROCESSOR for RISC-V

 arch/riscv/include/asm/suspend.h    |  3 ++
 arch/riscv/kernel/suspend.c         | 47 +++++++++++++++++
 drivers/acpi/Kconfig                |  2 +-
 drivers/acpi/riscv/Makefile         |  3 +-
 drivers/acpi/riscv/cpuidle.c        | 81 +++++++++++++++++++++++++++++
 drivers/cpuidle/cpuidle-riscv-sbi.c | 41 +--------------
 6 files changed, 135 insertions(+), 42 deletions(-)
 create mode 100644 drivers/acpi/riscv/cpuidle.c