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author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-01-10 02:07:12 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-01-10 02:07:12 +0100 |
commit | 5fda5698c289b2ff21d53d935c43351c424f8388 (patch) | |
tree | e9e065313881e5bcf0ab812d880de02668cebb34 /Documentation/driver-api | |
parent | Merge tag 'tag-chrome-platform-firmware-for-v6.8' of git://git.kernel.org/pub... (diff) | |
parent | platform/x86/amd/pmc: Modify SMU message port for latest AMD platform (diff) | |
download | linux-5fda5698c289b2ff21d53d935c43351c424f8388.tar.xz linux-5fda5698c289b2ff21d53d935c43351c424f8388.zip |
Merge tag 'platform-drivers-x86-v6.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86
Pull x86 platform driver updates from Hans de Goede:
- Intel PMC / PMT / TPMI / uncore-freq / vsec improvements and new
platform support
- AMD PMC / PMF improvements and new platform support
- AMD ACPI based Wifi band RFI mitigation feature (WBRF)
- WMI bus driver cleanups and improvements (Armin Wolf)
- acer-wmi Predator PHN16-71 support
- New Silicom network appliance EC LEDs / GPIOs driver
* tag 'platform-drivers-x86-v6.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86: (96 commits)
platform/x86/amd/pmc: Modify SMU message port for latest AMD platform
platform/x86/amd/pmc: Add 1Ah family series to STB support list
platform/x86/amd/pmc: Add idlemask support for 1Ah family
platform/x86/amd/pmc: call amd_pmc_get_ip_info() during driver probe
platform/x86/amd/pmc: Add VPE information for AMDI000A platform
platform/x86/amd/pmc: Send OS_HINT command for AMDI000A platform
platform/x86/amd/pmf: Return a status code only as a constant in two functions
platform/x86/amd/pmf: Return directly after a failed apmf_if_call() in apmf_sbios_heartbeat_notify()
platform/x86: wmi: linux/wmi.h: fix Excess kernel-doc description warning
platform/x86/intel/pmc: Add missing extern
platform/x86/intel/pmc/lnl: Add GBE LTR ignore during suspend
platform/x86/intel/pmc/arl: Add GBE LTR ignore during suspend
platform/x86: intel-uncore-freq: Add additional client processors
platform/x86: Remove "X86 PLATFORM DRIVERS - ARCH" from MAINTAINERS
platform/x86: hp-bioscfg: Removed needless asm-generic
platform/x86/intel/pmc: Add Lunar Lake M support to intel_pmc_core driver
platform/x86/intel/pmc: Add Arrow Lake S support to intel_pmc_core driver
platform/x86/intel/pmc: Add ssram_init flag in PMC discovery in Meteor Lake
platform/x86/intel/pmc: Move common code to core.c
platform/x86/intel/pmc: Add PSON residency counter for Alder Lake
...
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r-- | Documentation/driver-api/index.rst | 1 | ||||
-rw-r--r-- | Documentation/driver-api/wbrf.rst | 78 |
2 files changed, 79 insertions, 0 deletions
diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst index f549a68951d7..8bc4ebe7a36f 100644 --- a/Documentation/driver-api/index.rst +++ b/Documentation/driver-api/index.rst @@ -115,6 +115,7 @@ available subsections can be seen below. hte/index wmi dpll + wbrf .. only:: subproject and html diff --git a/Documentation/driver-api/wbrf.rst b/Documentation/driver-api/wbrf.rst new file mode 100644 index 000000000000..f48bfa029813 --- /dev/null +++ b/Documentation/driver-api/wbrf.rst @@ -0,0 +1,78 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +================================= +WBRF - Wifi Band RFI Mitigations +================================= + +Due to electrical and mechanical constraints in certain platform designs +there may be likely interference of relatively high-powered harmonics of +the GPU memory clocks with local radio module frequency bands used by +certain Wifi bands. + +To mitigate possible RFI interference producers can advertise the +frequencies in use and consumers can use this information to avoid using +these frequencies for sensitive features. + +When a platform is known to have this issue with any contained devices, +the platform designer will advertise the availability of this feature via +ACPI devices with a device specific method (_DSM). +* Producers with this _DSM will be able to advertise the frequencies in use. +* Consumers with this _DSM will be able to register for notifications of +frequencies in use. + +Some general terms +================== + +Producer: such component who can produce high-powered radio frequency +Consumer: such component who can adjust its in-use frequency in +response to the radio frequencies of other components to mitigate the +possible RFI. + +To make the mechanism function, those producers should notify active use +of their particular frequencies so that other consumers can make relative +internal adjustments as necessary to avoid this resonance. + +ACPI interface +============== + +Although initially used by for wifi + dGPU use cases, the ACPI interface +can be scaled to any type of device that a platform designer discovers +can cause interference. + +The GUID used for the _DSM is 7B7656CF-DC3D-4C1C-83E9-66E721DE3070. + +3 functions are available in this _DSM: + +* 0: discover # of functions available +* 1: record RF bands in use +* 2: retrieve RF bands in use + +Driver programming interface +============================ + +.. kernel-doc:: drivers/platform/x86/amd/wbrf.c + +Sample Usage +============= + +The expected flow for the producers: +1. During probe, call `acpi_amd_wbrf_supported_producer` to check if WBRF +can be enabled for the device. +2. On using some frequency band, call `acpi_amd_wbrf_add_remove` with 'add' +param to get other consumers properly notified. +3. Or on stopping using some frequency band, call +`acpi_amd_wbrf_add_remove` with 'remove' param to get other consumers notified. + +The expected flow for the consumers: +1. During probe, call `acpi_amd_wbrf_supported_consumer` to check if WBRF +can be enabled for the device. +2. Call `amd_wbrf_register_notifier` to register for notification +of frequency band change(add or remove) from other producers. +3. Call the `amd_wbrf_retrieve_freq_band` initally to retrieve +current active frequency bands considering some producers may broadcast +such information before the consumer is up. +4. On receiving a notification for frequency band change, run +`amd_wbrf_retrieve_freq_band` again to retrieve the latest +active frequency bands. +5. During driver cleanup, call `amd_wbrf_unregister_notifier` to +unregister the notifier. |