user/sven/linux.git/include/acpi/cppc_acpi.h, branch v6.6.55

ACPI: CPPC: Fix MASK_VAL() usage

2024-10-04T14:28:53Z

[ Upstream commit 60949b7b805424f21326b450ca4f1806c06d982e ] MASK_VAL() was added as a way to handle bit_offset and bit_width for registers located in system memory address space. However, while suited for reading, it does not work for writing and result in corrupted registers when writing values with bit_offset > 0. Moreover, when a register is collocated with another one at the same address but with a different mask, the current code results in the other registers being overwritten with 0s. The write procedure for SYSTEM_MEMORY registers should actually read the value, mask it, update it and write it with the updated value. Moreover, since registers can be located in the same word, we must take care of locking the access before doing it. We should potentially use a global lock since we don't know in if register addresses aren't shared with another _CPC package but better not encourage vendors to do so. Assume that registers can use the same word inside a _CPC package and thus, use a per _CPC package lock. Fixes: 2f4a4d63a193 ("ACPI: CPPC: Use access_width over bit_width for system memory accesses") Signed-off-by: Clément Léger Link: https://patch.msgid.link/20240826101648.95654-1-cleger@rivosinc.com [ rjw: Dropped redundant semicolon ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

ACPI: CPPC: Add helper to get the highest performance value

2024-09-12T09:11:40Z

commit 12753d71e8c5c3e716cedba23ddeed508da0bdc4 upstream. Add support for getting the highest performance to the generic CPPC driver. This enables downstream drivers such as amd-pstate to discover and use these values. Refer to Chapter 8.4.6.1.1.1. Highest Performance of ACPI Specification 6.5 for details on continuous performance control of CPPC (linked below). Tested-by: Oleksandr Natalenko Reviewed-by: Mario Limonciello Reviewed-by: Wyes Karny Reviewed-by: Perry Yuan Acked-by: Huang Rui Signed-off-by: Meng Li Link: https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html?highlight=cppc#highest-performance [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

ACPI: CPPC: Add auto select register read/write support

2023-03-17T18:06:23Z

For some AMD shared memory based systems, the autonomous selection bit needed to be set explicitly. Add autonomous selection register related APIs to acpi driver, which amd_pstate driver uses later. Acked-by: Huang Rui Reviewed-by: Mario Limonciello Tested-by: Oleksandr Natalenko Signed-off-by: Wyes Karny [ rjw: Fixed up kerneldoc comments, white space adjustment, subject edits ] Signed-off-by: Rafael J. Wysocki

ACPI: CPPC: Add AMD pstate energy performance preference cppc control

2023-02-03T20:59:41Z

Add support for setting and querying EPP preferences to the generic CPPC driver. This enables downstream drivers such as amd-pstate to discover and use these values. Downstream drivers that want to use the new symbols cppc_get_epp_caps and cppc_set_epp_perf for querying and setting EPP preferences will need to call cppc_set_epp_perf to enable the EPP function firstly. Acked-by: Huang Rui Reviewed-by: Mario Limonciello Reviewed-by: Wyes Karny Tested-by: Wyes Karny Signed-off-by: Perry Yuan Signed-off-by: Rafael J. Wysocki

ACPI: CPPC: Disable FIE if registers in PCC regions

2022-09-24T16:43:46Z

PCC regions utilize a mailbox to set/retrieve register values used by the CPPC code. This is fine as long as the operations are infrequent. With the FIE code enabled though the overhead can range from 2-11% of system CPU overhead (ex: as measured by top) on Arm based machines. So, before enabling FIE assure none of the registers used by cppc_get_perf_ctrs() are in the PCC region. Finally, add a module parameter which can override the PCC region detection at boot or module reload. Signed-off-by: Jeremy Linton Acked-by: Viresh Kumar Reviewed-by: Ionela Voinescu Signed-off-by: Rafael J. Wysocki

ACPI: CPPC: Do not prevent CPPC from working in the future

2022-07-26T18:56:49Z

There is a problem with the current revision checks in is_cppc_supported() that they essentially prevent the CPPC support from working if a new _CPC package format revision being a proper superset of the v3 and only causing _CPC to return a package with more entries (while retaining the types and meaning of the entries defined by the v3) is introduced in the future and used by the platform firmware. In that case, as long as the number of entries in the _CPC return package is at least CPPC_V3_NUM_ENT, it should be perfectly fine to use the v3 support code and disregard the additional package entries added by the new package format revision. For this reason, drop is_cppc_supported() altogether, put the revision checks directly into acpi_cppc_processor_probe() so they are easier to follow and rework them to take the case mentioned above into account. Fixes: 4773e77cdc9b ("ACPI / CPPC: Add support for CPPC v3") Cc: 4.18+ # 4.18+ Signed-off-by: Rafael J. Wysocki

ACPI: CPPC: Don't require _OSC if X86_FEATURE_CPPC is supported

2022-07-05T18:36:11Z

commit 72f2ecb7ece7 ("ACPI: bus: Set CPPC _OSC bits for all and when CPPC_LIB is supported") added support for claiming to support CPPC in _OSC on non-Intel platforms. This unfortunately caused a regression on a vartiety of AMD platforms in the field because a number of AMD platforms don't set the `_OSC` bit 5 or 6 to indicate CPPC or CPPC v2 support. As these AMD platforms already claim CPPC support via a dedicated MSR from `X86_FEATURE_CPPC`, use this enable this feature rather than requiring the `_OSC` on platforms with a dedicated MSR. If there is additional breakage on the shared memory designs also missing this _OSC, additional follow up changes may be needed. Fixes: 72f2ecb7ece7 ("Set CPPC _OSC bits for all and when CPPC_LIB is supported") Reported-by: Perry Yuan Signed-off-by: Mario Limonciello Signed-off-by: Rafael J. Wysocki

cpufreq: CPPC: Enable fast_switch

2022-05-19T17:45:34Z

The communication mean of the _CPC desired performance can be PCC, System Memory, System IO, or Functional Fixed Hardware. commit b7898fda5bc7 ("cpufreq: Support for fast frequency switching") fast_switching is 'for switching CPU frequencies from interrupt context'. Writes to SystemMemory and SystemIo are fast and suitable this. This is not the case for PCC and might not be the case for FFH. Enable fast_switching for the cppc_cpufreq driver in above cases. Add cppc_allow_fast_switch() to check the desired performance register address space and set fast_switching accordingly. Signed-off-by: Pierre Gondois Reviewed-by: Sudeep Holla Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

ACPI: CPPC: Add CPPC enable register function

2021-12-30T17:51:39Z

Add a new function to enable CPPC feature. This function will write Continuous Performance Control package EnableRegister field on the processor. CPPC EnableRegister register described in section 8.4.7.1 of ACPI 6.4: This element is optional. If supported, contains a resource descriptor with a single Register() descriptor that describes a register to which OSPM writes a One to enable CPPC on this processor. Before this register is set, the processor will be controlled by legacy mechanisms (ACPI Pstates, firmware, etc.). This register will be used for AMD processors to enable AMD P-State function instead of legacy ACPI P-States. Signed-off-by: Jinzhou Su Signed-off-by: Huang Rui Signed-off-by: Rafael J. Wysocki

ACPI: CPPC: Introduce cppc_get_nominal_perf()

2021-09-07T19:15:16Z

On some systems the nominal_perf value retrieved via CPPC is just a constant and fetching it doesn't require accessing any registers, so if it is the only CPPC capability that's needed, it is wasteful to run cppc_get_perf_caps() in order to get just that value alone, especially when this is done for CPUs other than the one running the code. For this reason, introduce cppc_get_nominal_perf() allowing nominal_perf to be obtained individually, by generalizing the existing cppc_get_desired_perf() (and renaming it) so it can be used to retrieve any specific CPPC capability value. While at it, clean up the cppc_get_desired_perf() kerneldoc comment a bit. Signed-off-by: Rafael J. Wysocki