diff options
| author | Sukumar Ghorai <sukumar.ghorai@intel.com> | 2023-09-28 23:44:30 -0700 |
|---|---|---|
| committer | Subrata Banik <subratabanik@google.com> | 2023-10-05 15:22:04 +0000 |
| commit | ed1c03a138ccfb4d1939f15fbe97ab0b8f7e4015 (patch) | |
| tree | 78f1fd8d32bc2227f9851fd271dafd977361662e /src/soc | |
| parent | 1e2541074f038f51df88921af3ea0d134fb1265f (diff) | |
soc/intel: separate slp-s0 residency counter frequency in LPIT table
Intel platforms use Low Power Idle Table (LPIT) to enumerate platform
Low Power Idle states. There are two types of low power residencies
a) CPU PKG C10 - read via MSR (Function fixed hardware interface)
b) Platform Controller Hub (PCH) SLP_S0 - read via memory mapped IO
Ref. https://www.uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf,
section 2.2.1: value of 0 indicates that counter runs at TSC frequency.
Ref. Intel 64 and IA-32 Architectures Software Developer’s Manual (Vol 4)
MSR 0x632: PC10 residency counter is at same frequency as the TSC.
Whereas slp_s0 residency counter running in different frequency.
BUG=b:300440936
TEST=check kernel cpuidle sysfs are created after kernel boot
cat /sys/devices/system/cpu/cpuidle/low_power_idle_cpu_residency_us
cat /sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us
Change-Id: Ibde764551a21b9aecb1c269948f4823548294711
Signed-off-by: Sukumar Ghorai <sukumar.ghorai@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78177
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Diffstat (limited to 'src/soc')
| -rw-r--r-- | src/soc/intel/common/block/acpi/lpit.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/soc/intel/common/block/acpi/lpit.c b/src/soc/intel/common/block/acpi/lpit.c index 38a402f13d..de1e71dc24 100644 --- a/src/soc/intel/common/block/acpi/lpit.c +++ b/src/soc/intel/common/block/acpi/lpit.c @@ -50,13 +50,13 @@ unsigned long acpi_fill_lpit(unsigned long current) sys_counter->entry_trigger.space_id = ACPI_ADDRESS_SPACE_FIXED; sys_counter->entry_trigger.access_size = ACPI_ACCESS_SIZE_UNDEFINED; - /* Slp_S0 residency counter */ + /* slp_s0 residency counter */ sys_counter->residency_counter.addrl = PCH_PWRM_BASE_ADDRESS + SLP_S0_RES; sys_counter->residency_counter.bit_offset = 0; sys_counter->residency_counter.bit_width = 32; sys_counter->residency_counter.space_id = ACPI_ADDRESS_SPACE_MEMORY; sys_counter->residency_counter.access_size = ACPI_ACCESS_SIZE_DWORD_ACCESS; - sys_counter->counter_frequency = ACPI_LPIT_CTR_FREQ_TSC; + sys_counter->counter_frequency = ACPI_LPIT_SLP_S0_FREQ; /* Min. residency and worst-case latency (from FSP and vendor dumps) */ sys_counter->min_residency = 30000; /* break-even: 30 ms */ |