Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) .. SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) ===========================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) Low Power Idle Table (LPIT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) ===========================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) To enumerate platform Low Power Idle states, Intel platforms are using
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) “Low Power Idle Table” (LPIT). More details about this table can be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) downloaded from:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) https://www.uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) Residencies for each low power state can be read via FFH
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) (Function fixed hardware) or a memory mapped interface.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) On platforms supporting S0ix sleep states, there can be two types of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) residencies:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)   - CPU PKG C10 (Read via FFH interface)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)   - Platform Controller Hub (PCH) SLP_S0 (Read via memory mapped interface)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) The following attributes are added dynamically to the cpuidle
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) sysfs attribute group::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)   /sys/devices/system/cpu/cpuidle/low_power_idle_cpu_residency_us
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)   /sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) The "low_power_idle_cpu_residency_us" attribute shows time spent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) by the CPU package in PKG C10
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) The "low_power_idle_system_residency_us" attribute shows SLP_S0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) residency, or system time spent with the SLP_S0# signal asserted.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) This is the lowest possible system power state, achieved only when CPU is in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) PKG C10 and all functional blocks in PCH are in a low power state.