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| author | Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> | 2017-10-06 02:24:03 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2017-10-11 16:38:10 +0300 |
| commit | eeb2d80d502af28e5660ff4bbe00f90ceb82c2db (patch) | |
| tree | 8d485561b5673a70d876008390dce3cc53e4b63a /include | |
| parent | c2ebf788f927dcca72beead19fab5f5aba79a098 (diff) | |
| download | linux-eeb2d80d502af28e5660ff4bbe00f90ceb82c2db.tar.xz | |
ACPI / LPIT: Add Low Power Idle Table (LPIT) support
Add functionality to read LPIT table, which provides:
- Sysfs interface to read residency counters via
/sys/devices/system/cpu/cpuidle/low_power_idle_cpu_residency_us
/sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us
Here the count "low_power_idle_cpu_residency_us" shows the time spent
by CPU package in low power state. This is read via MSR interface,
which points to MSR for PKG C10.
Here the count "low_power_idle_system_residency_us" show the count the
system was in low power state. This is read via MMIO interface. This
is mapped to SLP_S0 residency on modern Intel systems. This residency
is achieved only when CPU is in PKG C10 and all functional blocks are
in low power state.
It is possible that none of the above counters present or anyone of the
counter present or all counters present.
For example: On my Kabylake system both of the above counters present.
After suspend to idle these counts updated and prints:
6916179
6998564
This counter can be read by tools like turbostat to display. Or it can
be used to debug, if modern systems are reaching desired low power state.
- Provides an interface to read residency counter memory address
This address can be used to get the base address of PMC memory
mapped IO. This is utilized by intel_pmc_core driver to print
more debug information.
In addition, to avoid code duplication to read iomem, removed the read of
iomem from acpi_os_read_memory() in osl.c and made a common function
acpi_os_read_iomem(). This new function is used for reading iomem in
in both osl.c and acpi_lpit.c.
Link: http://www.uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/acpi/acpiosxf.h | 2 | ||||
| -rw-r--r-- | include/linux/acpi.h | 9 |
2 files changed, 11 insertions, 0 deletions
diff --git a/include/acpi/acpiosxf.h b/include/acpi/acpiosxf.h index c66eb8ffa454..d5c0f5153c4e 100644 --- a/include/acpi/acpiosxf.h +++ b/include/acpi/acpiosxf.h @@ -287,6 +287,8 @@ acpi_status acpi_os_write_port(acpi_io_address address, u32 value, u32 width); /* * Platform and hardware-independent physical memory interfaces */ +int acpi_os_read_iomem(void __iomem *virt_addr, u64 *value, u32 width); + #ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_read_memory acpi_status acpi_os_read_memory(acpi_physical_address address, u64 *value, u32 width); diff --git a/include/linux/acpi.h b/include/linux/acpi.h index d18c92d4ba19..2b1738f840ab 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -1248,4 +1248,13 @@ int acpi_irq_get(acpi_handle handle, unsigned int index, struct resource *res) } #endif +#ifdef CONFIG_ACPI_LPIT +int lpit_read_residency_count_address(u64 *address); +#else +static inline int lpit_read_residency_count_address(u64 *address) +{ + return -EINVAL; +} +#endif + #endif /*_LINUX_ACPI_H*/ |