diff options
| -rw-r--r-- | Documentation/driver-api/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/driver-api/wbrf.rst | 78 | ||||
| -rw-r--r-- | drivers/platform/x86/amd/Kconfig | 14 | ||||
| -rw-r--r-- | drivers/platform/x86/amd/Makefile | 1 | ||||
| -rw-r--r-- | drivers/platform/x86/amd/wbrf.c | 317 | ||||
| -rw-r--r-- | include/linux/acpi_amd_wbrf.h | 91 |
6 files changed, 502 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. diff --git a/drivers/platform/x86/amd/Kconfig b/drivers/platform/x86/amd/Kconfig index 55f3a2fc6aec..54753213cc61 100644 --- a/drivers/platform/x86/amd/Kconfig +++ b/drivers/platform/x86/amd/Kconfig @@ -18,3 +18,17 @@ config AMD_HSMP If you choose to compile this driver as a module the module will be called amd_hsmp. + +config AMD_WBRF + bool "AMD Wifi RF Band mitigations (WBRF)" + depends on ACPI + help + WBRF(Wifi Band RFI mitigation) mechanism allows Wifi drivers + to notify the frequencies they are using so that other hardware + can be reconfigured to avoid harmonic conflicts. + + AMD provides an ACPI based mechanism to support WBRF on platform with + appropriate underlying support. + + This mechanism will only be activated on platforms that advertise a + need for it. diff --git a/drivers/platform/x86/amd/Makefile b/drivers/platform/x86/amd/Makefile index f04932b7a7d1..dcec0a46f8af 100644 --- a/drivers/platform/x86/amd/Makefile +++ b/drivers/platform/x86/amd/Makefile @@ -8,3 +8,4 @@ obj-$(CONFIG_AMD_PMC) += pmc/ amd_hsmp-y := hsmp.o obj-$(CONFIG_AMD_HSMP) += amd_hsmp.o obj-$(CONFIG_AMD_PMF) += pmf/ +obj-$(CONFIG_AMD_WBRF) += wbrf.o diff --git a/drivers/platform/x86/amd/wbrf.c b/drivers/platform/x86/amd/wbrf.c new file mode 100644 index 000000000000..dd197b3aebe0 --- /dev/null +++ b/drivers/platform/x86/amd/wbrf.c @@ -0,0 +1,317 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Wifi Frequency Band Manage Interface + * Copyright (C) 2023 Advanced Micro Devices + */ + +#include <linux/acpi.h> +#include <linux/acpi_amd_wbrf.h> + +/* + * Functions bit vector for WBRF method + * + * Bit 0: WBRF supported. + * Bit 1: Function 1 (Add / Remove frequency) is supported. + * Bit 2: Function 2 (Get frequency list) is supported. + */ +#define WBRF_ENABLED 0x0 +#define WBRF_RECORD 0x1 +#define WBRF_RETRIEVE 0x2 + +#define WBRF_REVISION 0x1 + +/* + * The data structure used for WBRF_RETRIEVE is not naturally aligned. + * And unfortunately the design has been settled down. + */ +struct amd_wbrf_ranges_out { + u32 num_of_ranges; + struct freq_band_range band_list[MAX_NUM_OF_WBRF_RANGES]; +} __packed; + +static const guid_t wifi_acpi_dsm_guid = + GUID_INIT(0x7b7656cf, 0xdc3d, 0x4c1c, + 0x83, 0xe9, 0x66, 0xe7, 0x21, 0xde, 0x30, 0x70); + +/* + * Used to notify consumer (amdgpu driver currently) about + * the wifi frequency is change. + */ +static BLOCKING_NOTIFIER_HEAD(wbrf_chain_head); + +static int wbrf_record(struct acpi_device *adev, uint8_t action, struct wbrf_ranges_in_out *in) +{ + union acpi_object argv4; + union acpi_object *tmp; + union acpi_object *obj; + u32 num_of_ranges = 0; + u32 num_of_elements; + u32 arg_idx = 0; + int ret; + u32 i; + + if (!in) + return -EINVAL; + + for (i = 0; i < ARRAY_SIZE(in->band_list); i++) { + if (in->band_list[i].start && in->band_list[i].end) + num_of_ranges++; + } + + /* + * The num_of_ranges value in the "in" object supplied by + * the caller is required to be equal to the number of + * entries in the band_list array in there. + */ + if (num_of_ranges != in->num_of_ranges) + return -EINVAL; + + /* + * Every input frequency band comes with two end points(start/end) + * and each is accounted as an element. Meanwhile the range count + * and action type are accounted as an element each. + * So, the total element count = 2 * num_of_ranges + 1 + 1. + */ + num_of_elements = 2 * num_of_ranges + 2; + + tmp = kcalloc(num_of_elements, sizeof(*tmp), GFP_KERNEL); + if (!tmp) + return -ENOMEM; + + argv4.package.type = ACPI_TYPE_PACKAGE; + argv4.package.count = num_of_elements; + argv4.package.elements = tmp; + + /* save the number of ranges*/ + tmp[0].integer.type = ACPI_TYPE_INTEGER; + tmp[0].integer.value = num_of_ranges; + + /* save the action(WBRF_RECORD_ADD/REMOVE/RETRIEVE) */ + tmp[1].integer.type = ACPI_TYPE_INTEGER; + tmp[1].integer.value = action; + + arg_idx = 2; + for (i = 0; i < ARRAY_SIZE(in->band_list); i++) { + if (!in->band_list[i].start || !in->band_list[i].end) + continue; + + tmp[arg_idx].integer.type = ACPI_TYPE_INTEGER; + tmp[arg_idx++].integer.value = in->band_list[i].start; + tmp[arg_idx].integer.type = ACPI_TYPE_INTEGER; + tmp[arg_idx++].integer.value = in->band_list[i].end; + } + + obj = acpi_evaluate_dsm(adev->handle, &wifi_acpi_dsm_guid, + WBRF_REVISION, WBRF_RECORD, &argv4); + + if (!obj) + return -EINVAL; + + if (obj->type != ACPI_TYPE_INTEGER) { + ret = -EINVAL; + goto out; + } + + ret = obj->integer.value; + if (ret) + ret = -EINVAL; + +out: + ACPI_FREE(obj); + kfree(tmp); + + return ret; +} + +/** + * acpi_amd_wbrf_add_remove - add or remove the frequency band the device is using + * + * @dev: device pointer + * @action: remove or add the frequency band into bios + * @in: input structure containing the frequency band the device is using + * + * Broadcast to other consumers the frequency band the device starts + * to use. Underneath the surface the information is cached into an + * internal buffer first. Then a notification is sent to all those + * registered consumers. So then they can retrieve that buffer to + * know the latest active frequency bands. Consumers that haven't + * yet been registered can retrieve the information from the cache + * when they register. + * + * Return: + * 0 for success add/remove wifi frequency band. + * Returns a negative error code for failure. + */ +int acpi_amd_wbrf_add_remove(struct device *dev, uint8_t action, struct wbrf_ranges_in_out *in) +{ + struct acpi_device *adev; + int ret; + + adev = ACPI_COMPANION(dev); + if (!adev) + return -ENODEV; + + ret = wbrf_record(adev, action, in); + if (ret) + return ret; + + blocking_notifier_call_chain(&wbrf_chain_head, WBRF_CHANGED, NULL); + + return 0; +} +EXPORT_SYMBOL_GPL(acpi_amd_wbrf_add_remove); + +/** + * acpi_amd_wbrf_supported_producer - determine if the WBRF can be enabled + * for the device as a producer + * + * @dev: device pointer + * + * Check if the platform equipped with necessary implementations to + * support WBRF for the device as a producer. + * + * Return: + * true if WBRF is supported, otherwise returns false + */ +bool acpi_amd_wbrf_supported_producer(struct device *dev) +{ + struct acpi_device *adev; + + adev = ACPI_COMPANION(dev); + if (!adev) + return false; + + return acpi_check_dsm(adev->handle, &wifi_acpi_dsm_guid, + WBRF_REVISION, BIT(WBRF_RECORD)); +} +EXPORT_SYMBOL_GPL(acpi_amd_wbrf_supported_producer); + +/** + * acpi_amd_wbrf_supported_consumer - determine if the WBRF can be enabled + * for the device as a consumer + * + * @dev: device pointer + * + * Determine if the platform equipped with necessary implementations to + * support WBRF for the device as a consumer. + * + * Return: + * true if WBRF is supported, otherwise returns false. + */ +bool acpi_amd_wbrf_supported_consumer(struct device *dev) +{ + struct acpi_device *adev; + + adev = ACPI_COMPANION(dev); + if (!adev) + return false; + + return acpi_check_dsm(adev->handle, &wifi_acpi_dsm_guid, + WBRF_REVISION, BIT(WBRF_RETRIEVE)); +} +EXPORT_SYMBOL_GPL(acpi_amd_wbrf_supported_consumer); + +/** + * amd_wbrf_retrieve_freq_band - retrieve current active frequency bands + * + * @dev: device pointer + * @out: output structure containing all the active frequency bands + * + * Retrieve the current active frequency bands which were broadcasted + * by other producers. The consumer who calls this API should take + * proper actions if any of the frequency band may cause RFI with its + * own frequency band used. + * + * Return: + * 0 for getting wifi freq band successfully. + * Returns a negative error code for failure. + */ +int amd_wbrf_retrieve_freq_band(struct device *dev, struct wbrf_ranges_in_out *out) +{ + struct amd_wbrf_ranges_out acpi_out = {0}; + struct acpi_device *adev; + union acpi_object *obj; + union acpi_object param; + int ret = 0; + + adev = ACPI_COMPANION(dev); + if (!adev) + return -ENODEV; + + param.type = ACPI_TYPE_STRING; + param.string.length = 0; + param.string.pointer = NULL; + + obj = acpi_evaluate_dsm(adev->handle, &wifi_acpi_dsm_guid, + WBRF_REVISION, WBRF_RETRIEVE, ¶m); + if (!obj) + return -EINVAL; + + /* + * The return buffer is with variable length and the format below: + * number_of_entries(1 DWORD): Number of entries + * start_freq of 1st entry(1 QWORD): Start frequency of the 1st entry + * end_freq of 1st entry(1 QWORD): End frequency of the 1st entry + * ... + * ... + * start_freq of the last entry(1 QWORD) + * end_freq of the last entry(1 QWORD) + * + * Thus the buffer length is determined by the number of entries. + * - For zero entry scenario, the buffer length will be 4 bytes. + * - For one entry scenario, the buffer length will be 20 bytes. + */ + if (obj->buffer.length > sizeof(acpi_out) || obj->buffer.length < 4) { + dev_err(dev, "Wrong sized WBRT information"); + ret = -EINVAL; + goto out; + } + memcpy(&acpi_out, obj->buffer.pointer, obj->buffer.length); + + out->num_of_ranges = acpi_out.num_of_ranges; + memcpy(out->band_list, acpi_out.band_list, sizeof(acpi_out.band_list)); + +out: + ACPI_FREE(obj); + return ret; +} +EXPORT_SYMBOL_GPL(amd_wbrf_retrieve_freq_band); + +/** + * amd_wbrf_register_notifier - register for notifications of frequency + * band update + * + * @nb: driver notifier block + * + * The consumer should register itself via this API so that it can get + * notified on the frequency band updates from other producers. + * + * Return: + * 0 for registering a consumer driver successfully. + * Returns a negative error code for failure. + */ +int amd_wbrf_register_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&wbrf_chain_head, nb); +} +EXPORT_SYMBOL_GPL(amd_wbrf_register_notifier); + +/** + * amd_wbrf_unregister_notifier - unregister for notifications of + * frequency band update + * + * @nb: driver notifier block + * + * The consumer should call this API when it is longer interested with + * the frequency band updates from other producers. Usually, this should + * be performed during driver cleanup. + * + * Return: + * 0 for unregistering a consumer driver. + * Returns a negative error code for failure. + */ +int amd_wbrf_unregister_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&wbrf_chain_head, nb); +} +EXPORT_SYMBOL_GPL(amd_wbrf_unregister_notifier); diff --git a/include/linux/acpi_amd_wbrf.h b/include/linux/acpi_amd_wbrf.h new file mode 100644 index 000000000000..898f31d536d4 --- /dev/null +++ b/include/linux/acpi_amd_wbrf.h @@ -0,0 +1,91 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Wifi Band Exclusion Interface (AMD ACPI Implementation) + * Copyright (C) 2023 Advanced Micro Devices + */ + +#ifndef _ACPI_AMD_WBRF_H +#define _ACPI_AMD_WBRF_H + +#include <linux/device.h> +#include <linux/notifier.h> + +/* The maximum number of frequency band ranges */ +#define MAX_NUM_OF_WBRF_RANGES 11 + +/* Record actions */ +#define WBRF_RECORD_ADD 0x0 +#define WBRF_RECORD_REMOVE 0x1 + +/** + * struct freq_band_range - Wifi frequency band range definition + * @start: start frequency point (in Hz) + * @end: end frequency point (in Hz) + */ +struct freq_band_range { + u64 start; + u64 end; +}; + +/** + * struct wbrf_ranges_in_out - wbrf ranges info + * @num_of_ranges: total number of band ranges in this struct + * @band_list: array of Wifi band ranges + */ +struct wbrf_ranges_in_out { + u64 num_of_ranges; + struct freq_band_range band_list[MAX_NUM_OF_WBRF_RANGES]; +}; + +/** + * enum wbrf_notifier_actions - wbrf notifier actions index + * @WBRF_CHANGED: there was some frequency band updates. The consumers + * should retrieve the latest active frequency bands. + */ +enum wbrf_notifier_actions { + WBRF_CHANGED, +}; + +#if IS_ENABLED(CONFIG_AMD_WBRF) +bool acpi_amd_wbrf_supported_producer(struct device *dev); +int acpi_amd_wbrf_add_remove(struct device *dev, uint8_t action, struct wbrf_ranges_in_out *in); +bool acpi_amd_wbrf_supported_consumer(struct device *dev); +int amd_wbrf_retrieve_freq_band(struct device *dev, struct wbrf_ranges_in_out *out); +int amd_wbrf_register_notifier(struct notifier_block *nb); +int amd_wbrf_unregister_notifier(struct notifier_block *nb); +#else +static inline +bool acpi_amd_wbrf_supported_consumer(struct device *dev) +{ + return false; +} + +static inline +int acpi_amd_wbrf_add_remove(struct device *dev, uint8_t action, struct wbrf_ranges_in_out *in) +{ + return -ENODEV; +} + +static inline +bool acpi_amd_wbrf_supported_producer(struct device *dev) +{ + return false; +} +static inline +int amd_wbrf_retrieve_freq_band(struct device *dev, struct wbrf_ranges_in_out *out) +{ + return -ENODEV; +} +static inline +int amd_wbrf_register_notifier(struct notifier_block *nb) +{ + return -ENODEV; +} +static inline +int amd_wbrf_unregister_notifier(struct notifier_block *nb) +{ + return -ENODEV; +} +#endif /* CONFIG_AMD_WBRF */ + +#endif /* _ACPI_AMD_WBRF_H */ |