Hi Mario,
On 11/30/2023 1:24 AM, Mario Limonciello wrote:
> On 11/29/2023 03:13, Ma Jun wrote:
>> Due to electrical and mechanical constraints in certain platform designs
>> there may be likely interference of relatively high-powered harmonics of
>> the (G-)DDR memory clocks with local radio module frequency bands used
>> by Wifi 6/6e/7.
>>
>> To mitigate this, AMD has introduced a mechanism that devices can use to
>> notify active use of particular frequencies so that other devices can make
>> relative internal adjustments as necessary to avoid this resonance.
>>
>> Co-developed-by: Evan Quan <quanliangl@xxxxxxxxxxx>
>> Signed-off-by: Evan Quan <quanliangl@xxxxxxxxxxx>
>> Signed-off-by: Ma Jun <Jun.Ma2@xxxxxxx>
>
> I have one very minor nit below that if no other feedback is needed for
> the series can be fixed when committing.
>
> Reviewed-by: Mario Limonciello <mario.limonciello@xxxxxxx>
>
>>
>> --
>> v11:
>> - fix typo(Simon)
>> v12:
>> - Fix the code logic (Rafael)
>> - Move amd_wbrf.c to drivers/platform/x86/amd/wbrf.c
>> - Updated Evan's email because he's no longer at AMD.Thanks
>> for his work in earlier versions.
>> v13:
>> - Fix the format issue (IIpo Jarvinen)
>> - Add comment for some functions
>> v14:
>> - Use the apci_check_dsm and acpi_evaluate_dsm (Hans de Goede)
>> ---
>> drivers/platform/x86/amd/Kconfig | 15 ++
>> drivers/platform/x86/amd/Makefile | 1 +
>> drivers/platform/x86/amd/wbrf.c | 337 ++++++++++++++++++++++++++++++
>> include/linux/acpi_amd_wbrf.h | 94 +++++++++
>> 4 files changed, 447 insertions(+)
>> create mode 100644 drivers/platform/x86/amd/wbrf.c
>> create mode 100644 include/linux/acpi_amd_wbrf.h
>>
>> diff --git a/drivers/platform/x86/amd/Kconfig b/drivers/platform/x86/amd/Kconfig
>> index 55f3a2fc6aec..ac2b7758a04f 100644
>> --- a/drivers/platform/x86/amd/Kconfig
>> +++ b/drivers/platform/x86/amd/Kconfig
>> @@ -18,3 +18,18 @@ 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
>> + default n
>
> I believe the "default n" is unnecessary as it's implied.
Thanks for review. I'll fix this and other issues your commented
in the next version.
Regards,
Ma Jun
>
>> + 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..36e90a1159be
>> --- /dev/null
>> +++ b/drivers/platform/x86/amd/wbrf.c
>> @@ -0,0 +1,337 @@
>> +// 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>
>> +
>> +#define ACPI_AMD_WBRF_METHOD "\\WBRF"
>> +
>> +/*
>> + * 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);
>> +
>> +static bool acpi_amd_wbrf_supported_system(void)
>> +{
>> + acpi_status status;
>> + acpi_handle handle;
>> +
>> + status = acpi_get_handle(NULL, ACPI_AMD_WBRF_METHOD, &handle);
>> +
>> + return ACPI_SUCCESS(status);
>> +}
>> +
>> +/**
>> + * 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;
>> +
>> + if (!acpi_amd_wbrf_supported_system())
>> + 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;
>> +
>> + if (!acpi_amd_wbrf_supported_system())
>> + 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..15b54734a080
>> --- /dev/null
>> +++ b/include/linux/acpi_amd_wbrf.h
>> @@ -0,0 +1,94 @@
>> +/* 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_remove_exclusion(struct device *dev, struct wbrf_ranges_in_out *in)
>> +{
>> + return -ENODEV;
>> +}
>> +static inline
>> +int acpi_amd_wbrf_add_exclusion(struct device *dev, 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 */
>
