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authorJakub Kicinski <kuba@kernel.org>2023-12-19 03:17:33 +0300
committerJakub Kicinski <kuba@kernel.org>2023-12-19 03:17:34 +0300
commit0ee28c9ae042e77100fae2cd82a54750668aafce (patch)
treea41dac49bb40eb4529bb49b31edea60802c76ec0 /Documentation
parent509afc7452707e62fb7c4bb257f111617332ffad (diff)
parentc5a3f56fcdb0a48a20772e4c9b8adc6c7256a461 (diff)
downloadlinux-0ee28c9ae042e77100fae2cd82a54750668aafce.tar.xz
Merge tag 'wireless-next-2023-12-18' of git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next
Kalle Valo says: ==================== wireless-next patches for v6.8 The second features pull request for v6.8. A bigger one this time with changes both to stack and drivers. We have a new Wifi band RFI (WBRF) mitigation feature for which we pulled an immutable branch shared with other subsystems. And, as always, other new features and bug fixes all over. Major changes: cfg80211/mac80211 * AMD ACPI based Wifi band RFI (WBRF) mitigation feature * Basic Service Set (BSS) usage reporting * TID to link mapping support * mac80211 hardware flag to disallow puncturing iwlwifi * new debugfs file fw_dbg_clear mt76 * NVMEM EEPROM improvements * mt7996 Extremely High Throughpu (EHT) improvements * mt7996 Wireless Ethernet Dispatcher (WED) support * mt7996 36-bit DMA support ath12k * support one MSI vector * WCN7850: support AP mode * tag 'wireless-next-2023-12-18' of git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next: (207 commits) wifi: mt76: mt7996: Use DECLARE_FLEX_ARRAY() and fix -Warray-bounds warnings wifi: ath11k: workaround too long expansion sparse warnings Revert "wifi: ath12k: use ATH12K_PCI_IRQ_DP_OFFSET for DP IRQ" wifi: rt2x00: remove useless code in rt2x00queue_create_tx_descriptor() wifi: rtw89: only reset BB/RF for existing WiFi 6 chips while starting up wifi: rtw89: add DBCC H2C to notify firmware the status wifi: rtw89: mac: add suffix _ax to MAC functions wifi: rtw89: mac: add flags to check if CMAC and DMAC are enabled wifi: rtw89: 8922a: add power on/off functions wifi: rtw89: add XTAL SI for WiFi 7 chips wifi: rtw89: phy: print out RFK log with formatted string wifi: rtw89: parse and print out RFK log from C2H events wifi: rtw89: add C2H event handlers of RFK log and report wifi: rtw89: load RFK log format string from firmware file wifi: rtw89: fw: add version field to BB MCU firmware element wifi: rtw89: fw: load TX power track tables from fw_element wifi: mwifiex: configure BSSID consistently when starting AP wifi: mwifiex: add extra delay for firmware ready wifi: mac80211: sta_info.c: fix sentence grammar wifi: mac80211: rx.c: fix sentence grammar ... ==================== Link: https://lore.kernel.org/r/20231218163900.C031DC433C9@smtp.kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/driver-api/index.rst1
-rw-r--r--Documentation/driver-api/wbrf.rst78
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.