Commit Graph

21 Commits

Author SHA1 Message Date
Mario Limonciello (AMD)
7e173bc310 cpufreq/amd-pstate-ut: Add a unit test for raw EPP
Ensure that all supported raw EPP values work properly.

Export the driver helpers used by the test module so the test can drive
raw EPP writes and temporarily disable dynamic EPP while it runs.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
2026-04-02 11:30:19 -05:00
Mario Limonciello (AMD)
6927f21852 cpufreq/amd-pstate: Add support for raw EPP writes
The energy performance preference field of the CPPC request MSR
supports values from 0 to 255, but the strings only offer 4 values.

The other values are useful for tuning the performance of some
workloads.

Add support for writing the raw energy performance preference value
to the sysfs file.  If the last value written was an integer then
an integer will be returned.  If the last value written was a string
then a string will be returned.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
2026-04-02 11:29:25 -05:00
Mario Limonciello (AMD)
798c47593c cpufreq/amd-pstate: Add support for platform profile class
The platform profile core allows multiple drivers and devices to
register platform profile support.

When the legacy platform profile interface is used all drivers will
adjust the platform profile as well.

Add support for registering every CPU with the platform profile handler
when dynamic EPP is enabled.

The end result will be that changing the platform profile will modify
EPP accordingly.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
2026-04-02 11:29:15 -05:00
Mario Limonciello (AMD)
e30ca6dd53 cpufreq/amd-pstate: Add dynamic energy performance preference
Dynamic energy performance preference changes the EPP profile based on
whether the machine is running on AC or DC power.

A notification chain from the power supply core is used to adjust EPP
values on plug in or plug out events.

When enabled, the driver exposes a sysfs toggle for dynamic EPP, blocks
manual writes to energy_performance_preference while it "owns" the EPP
updates.

For non-server systems:
    * the default EPP for AC mode is `performance`.
    * the default EPP for DC mode is `balance_performance`.

For server systems dynamic EPP is mostly a no-op.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
2026-04-02 11:29:02 -05:00
Mario Limonciello (AMD)
8cdc494013 cpufreq/amd-pstate: Cache the max frequency in cpudata
The value of maximum frequency is fixed and never changes. Doing
calculations every time based off of perf is unnecessary.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://lore.kernel.org/r/20260326193620.649441-1-mario.limonciello@amd.com
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
2026-04-02 11:28:54 -05:00
Gautham R. Shenoy
3b90e5a417 amd-pstate-ut: Add a testcase to validate the visibility of driver attributes
amd-pstate driver has per-attribute visibility functions to
dynamically control which sysfs freq_attrs are exposed based on the
platform capabilities and the current amd_pstate mode. However, there
is no test coverage to validate that the driver's live attribute list
matches the expected visibility for each mode.

Add amd_pstate_ut_check_freq_attrs() to the amd-pstate unit test
module. For each enabled mode (passive, active, guided), the test
independently derives the expected visibility of each attribute:
  - Core attributes (max_freq, lowest_nonlinear_freq, highest_perf)
    are always expected.
  - Prefcore attributes (prefcore_ranking, hw_prefcore) are expected
    only when cpudata->hw_prefcore indicates platform support.
  - EPP attributes (energy_performance_preference,
    energy_performance_available_preferences) are expected only in
    active mode.
  - Floor frequency attributes (floor_freq, floor_count) are expected
    only when X86_FEATURE_CPPC_PERF_PRIO is present.

Compare these independent expectations against the live driver's attr
array, catching bugs such as attributes leaking into wrong modes or
visibility functions checking incorrect conditions.

Signed-off-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
2026-04-02 11:28:40 -05:00
Gautham R. Shenoy
b9f103d096 amd-pstate: Add sysfs support for floor_freq and floor_count
When Floor Performance feature is supported by the platform, expose
two sysfs files:

   * amd_pstate_floor_freq to allow userspace to request the floor
     frequency for each CPU.

   * amd_pstate_floor_count which advertises the number of distinct
     levels of floor frequencies supported on this platform.

Reset the floor_perf to bios_floor_perf in the suspend, offline, and
exit paths, and restore the value to the cached user-request
floor_freq on the resume and online paths mirroring how bios_min_perf
is handled for MSR_AMD_CPPC_REQ.

Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
2026-04-02 11:28:28 -05:00
Gautham R. Shenoy
97838281f5 amd-pstate: Add support for CPPC_REQ2 and FLOOR_PERF
Some future AMD processors have feature named "CPPC Performance
Priority" which lets userspace specify different floor performance
levels for different CPUs. The platform firmware takes these different
floor performance levels into consideration while throttling the CPUs
under power/thermal constraints. The presence of this feature is
indicated by bit 16 of the EDX register for CPUID leaf
0x80000007. More details can be found in AMD Publication titled "AMD64
Collaborative Processor Performance Control (CPPC) Performance
Priority" Revision 1.10.

The number of distinct floor performance levels supported on the
platform will be advertised through the bits 32:39 of the
MSR_AMD_CPPC_CAP1. Bits 0:7 of a new MSR MSR_AMD_CPPC_REQ2
(0xc00102b5) will be used to specify the desired floor performance
level for that CPU.

Add support for the aforementioned MSR_AMD_CPPC_REQ2, and macros for
parsing and updating the relevant bits from MSR_AMD_CPPC_CAP1 and
MSR_AMD_CPPC_REQ2.

On boot if the default value of the MSR_AMD_CPPC_REQ2[7:0] (Floor
Perf) is lower than CPPC.lowest_perf, and thus invalid, initialize it
to MSR_AMD_CPPC_CAP1.nominal_perf which is a sane default value.

Save the boot-time floor_perf during amd_pstate_init_floor_perf(). In
a subsequent patch it will be restored in the suspend, offline, and
exit paths, mirroring how bios_min_perf is handled for
MSR_AMD_CPPC_REQ.

Link: https://docs.amd.com/v/u/en-US/69206_1.10_AMD64_CPPC_PUB
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
2026-04-02 11:28:24 -05:00
Swapnil Sapkal
d26d16438b amd-pstate-ut: Reset amd-pstate driver mode after running selftests
In amd-pstate-ut, one of the basic test is to switch between all
possible mode combinations. After running this test the mode of the
amd-pstate driver is active mode. Store and reset the mode to its original
state.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20250430064206.7402-1-swapnil.sapkal@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
2025-05-05 12:07:42 -05:00
Dhananjay Ugwekar
608a76b652 cpufreq/amd-pstate: Add support for the "Requested CPU Min frequency" BIOS option
Initialize lower frequency limit to the "Requested CPU Min frequency"
BIOS option (if it is set) value as part of the driver->init()
callback. The BIOS specified value is passed by the PMFW as min_perf in
CPPC_REQ MSR. To ensure that we don't mistake a stale min_perf value in
CPPC_REQ value as the "Requested CPU Min frequency" during a kexec wakeup,
reset the CPPC_REQ.min_perf value back to the BIOS specified one in the
offline, exit and suspend callbacks.

amd_pstate_target() and amd_pstate_epp_update_limit() which are invoked
as part of the resume() and online() callbacks will take care of restoring
the CPPC_REQ back to the correct values.

Signed-off-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20250428071623.4309-1-dhananjay.ugwekar@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
2025-04-28 16:09:35 -05:00
Mario Limonciello
4e16c11752 cpufreq/amd-pstate: Stop caching EPP
EPP values are cached in the cpudata structure per CPU. This is needless
though because they are also cached in the CPPC request variable.

Drop the separate cache for EPP values and always reference the CPPC
request variable when needed.

Reviewed-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
2025-03-06 13:01:26 -06:00
Mario Limonciello
f458cf79d7 cpufreq/amd-pstate: Drop cppc_cap1_cached
The `cppc_cap1_cached` variable isn't used at all, there is no
need to read it at initialization for each CPU.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Reviewed-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
2025-03-06 13:01:25 -06:00
Mario Limonciello
009d1c29a4 cpufreq/amd-pstate: Move perf values into a union
By storing perf values in a union all the writes and reads can
be done atomically, removing the need for some concurrency protections.

While making this change, also drop the cached frequency values,
using inline helpers to calculate them on demand from perf value.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Reviewed-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
2025-03-06 13:01:24 -06:00
Mario Limonciello
a9b9b4c2a4 cpufreq/amd-pstate: Drop min and max cached frequencies
Use the perf_to_freq helpers to calculate this on the fly.
As the members are no longer cached add an extra check into
amd_pstate_epp_update_limit() to avoid unnecessary calls in
amd_pstate_update_min_max_limit().

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Reviewed-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
2025-03-06 13:01:24 -06:00
Dhananjay Ugwekar
555bbe67a6 cpufreq/amd-pstate: Convert all perf values to u8
All perf values are always within 0-255 range, hence convert their
datatype to u8 everywhere.

Signed-off-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://lore.kernel.org/r/20250205112523.201101-7-dhananjay.ugwekar@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
2025-02-23 18:54:56 -06:00
Mario Limonciello
95fad7fb58 cpufreq/amd-pstate: Drop boost_state variable
Currently boost_state is cached for every processor in cpudata structure
and driver boost state is set for every processor.

Both of these aren't necessary as the driver only needs to set once and
the policy stores whether boost is enabled.

Move the driver boost setting to registration and adjust all references
to cached value to pull from the policy instead.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://lore.kernel.org/r/20241209185248.16301-16-mario.limonciello@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
2024-12-11 10:44:53 -06:00
Mario Limonciello
3b43739824 cpufreq/amd-pstate: Drop cached epp_policy variable
epp_policy is not used by any of the current code and there
is no need to cache it.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://lore.kernel.org/r/20241209185248.16301-6-mario.limonciello@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
2024-12-11 10:44:52 -06:00
Mario Limonciello
8d916815b0 cpufreq/amd-pstate: Export symbols for changing modes
In order to effectively test all mode switch combinations export
everything necessarily for amd-pstate-ut to trigger a mode switch.

Reviewed-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
2024-09-11 10:23:23 -05:00
Perry Yuan
c8c68c38b5 cpufreq: amd-pstate: initialize core precision boost state
The "Core Performance Boost (CPB) feature, when enabled in the BIOS,
allows the OS to control the highest performance for each individual
core. The active, passive and the guided modes of the amd-pstate driver
do support controlling the core frequency boost when this BIOS feature
is enabled. Additionally, the amd-pstate driver provides a sysfs
interface allowing the user to activate/deactivate this core performance
boost feature at runtime.

Add support for the set_boost callback in the active mode driver to
enable boost control via the cpufreq core. This ensures a consistent
boost control interface across all pstate modes, including passive
mode, guided mode, and active mode.

With this addition, all three pstate modes can support the same boost
control interface with unique interface and global CPB control. Each
CPU also supports individual boost control, allowing global CPB to
change all cores' boost states simultaneously. Specific CPUs can
update their boost states separately, ensuring all cores' boost
states are synchronized.

Cc: Oleksandr Natalenko <oleksandr@natalenko.name>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217931
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://lore.kernel.org/r/20240626042733.3747-3-mario.limonciello@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
2024-06-26 15:48:21 -05:00
Mario Limonciello
fc6e083726 cpufreq: amd-pstate: Allow users to write 'default' EPP string
The EPP string for 'default' represents what the firmware had configured
as the default EPP value but once a user changes EPP to another string
they can't reset it back to 'default'.

Cache the firmware EPP value and allow the user to write 'default' using
this value.

Reported-by: Artem S. Tashkinov <aros@gmx.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217931#c61
Reviewed-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
2024-06-20 21:52:05 -05:00
Arnd Bergmann
779b8a14af cpufreq: amd-pstate: remove global header file
When extra warnings are enabled, gcc points out a global variable
definition in a header:

In file included from drivers/cpufreq/amd-pstate-ut.c:29:
include/linux/amd-pstate.h:123:27: error: 'amd_pstate_mode_string' defined but not used [-Werror=unused-const-variable=]
  123 | static const char * const amd_pstate_mode_string[] = {
      |                           ^~~~~~~~~~~~~~~~~~~~~~

This header is only included from two files in the same directory,
and one of them uses only a single definition from it, so clean it
up by moving most of the contents into the driver that uses them,
and making shared bits a local header file.

Fixes: 36c5014e54 ("cpufreq: amd-pstate: optimize driver working mode selection in amd_pstate_param()")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2024-05-28 21:59:39 +02:00