// 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; 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; union acpi_object *tmp __free(kfree) = kzalloc_objs(*tmp, num_of_elements); 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; } union acpi_object *obj __free(kfree) = acpi_evaluate_dsm(adev->handle, &wifi_acpi_dsm_guid, WBRF_REVISION, WBRF_RECORD, &argv4); if (!obj) return -EINVAL; if (obj->type != ACPI_TYPE_INTEGER) return -EINVAL; ret = obj->integer.value; if (ret) return -EINVAL; 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);
