1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Wifi Frequency Band Manage Interface 4 * Copyright (C) 2023 Advanced Micro Devices 5 */ 6 7 #include <linux/acpi.h> 8 #include <linux/acpi_amd_wbrf.h> 9 10 /* 11 * Functions bit vector for WBRF method 12 * 13 * Bit 0: WBRF supported. 14 * Bit 1: Function 1 (Add / Remove frequency) is supported. 15 * Bit 2: Function 2 (Get frequency list) is supported. 16 */ 17 #define WBRF_ENABLED 0x0 18 #define WBRF_RECORD 0x1 19 #define WBRF_RETRIEVE 0x2 20 21 #define WBRF_REVISION 0x1 22 23 /* 24 * The data structure used for WBRF_RETRIEVE is not naturally aligned. 25 * And unfortunately the design has been settled down. 26 */ 27 struct amd_wbrf_ranges_out { 28 u32 num_of_ranges; 29 struct freq_band_range band_list[MAX_NUM_OF_WBRF_RANGES]; 30 } __packed; 31 32 static const guid_t wifi_acpi_dsm_guid = 33 GUID_INIT(0x7b7656cf, 0xdc3d, 0x4c1c, 34 0x83, 0xe9, 0x66, 0xe7, 0x21, 0xde, 0x30, 0x70); 35 36 /* 37 * Used to notify consumer (amdgpu driver currently) about 38 * the wifi frequency is change. 39 */ 40 static BLOCKING_NOTIFIER_HEAD(wbrf_chain_head); 41 42 static int wbrf_record(struct acpi_device *adev, uint8_t action, struct wbrf_ranges_in_out *in) 43 { 44 union acpi_object argv4; 45 u32 num_of_ranges = 0; 46 u32 num_of_elements; 47 u32 arg_idx = 0; 48 int ret; 49 u32 i; 50 51 if (!in) 52 return -EINVAL; 53 54 for (i = 0; i < ARRAY_SIZE(in->band_list); i++) { 55 if (in->band_list[i].start && in->band_list[i].end) 56 num_of_ranges++; 57 } 58 59 /* 60 * The num_of_ranges value in the "in" object supplied by 61 * the caller is required to be equal to the number of 62 * entries in the band_list array in there. 63 */ 64 if (num_of_ranges != in->num_of_ranges) 65 return -EINVAL; 66 67 /* 68 * Every input frequency band comes with two end points(start/end) 69 * and each is accounted as an element. Meanwhile the range count 70 * and action type are accounted as an element each. 71 * So, the total element count = 2 * num_of_ranges + 1 + 1. 72 */ 73 num_of_elements = 2 * num_of_ranges + 2; 74 75 union acpi_object *tmp __free(kfree) = kzalloc_objs(*tmp, 76 num_of_elements); 77 if (!tmp) 78 return -ENOMEM; 79 80 argv4.package.type = ACPI_TYPE_PACKAGE; 81 argv4.package.count = num_of_elements; 82 argv4.package.elements = tmp; 83 84 /* save the number of ranges*/ 85 tmp[0].integer.type = ACPI_TYPE_INTEGER; 86 tmp[0].integer.value = num_of_ranges; 87 88 /* save the action(WBRF_RECORD_ADD/REMOVE/RETRIEVE) */ 89 tmp[1].integer.type = ACPI_TYPE_INTEGER; 90 tmp[1].integer.value = action; 91 92 arg_idx = 2; 93 for (i = 0; i < ARRAY_SIZE(in->band_list); i++) { 94 if (!in->band_list[i].start || !in->band_list[i].end) 95 continue; 96 97 tmp[arg_idx].integer.type = ACPI_TYPE_INTEGER; 98 tmp[arg_idx++].integer.value = in->band_list[i].start; 99 tmp[arg_idx].integer.type = ACPI_TYPE_INTEGER; 100 tmp[arg_idx++].integer.value = in->band_list[i].end; 101 } 102 103 union acpi_object *obj __free(kfree) = 104 acpi_evaluate_dsm(adev->handle, &wifi_acpi_dsm_guid, 105 WBRF_REVISION, WBRF_RECORD, &argv4); 106 107 if (!obj) 108 return -EINVAL; 109 110 if (obj->type != ACPI_TYPE_INTEGER) 111 return -EINVAL; 112 113 ret = obj->integer.value; 114 if (ret) 115 return -EINVAL; 116 117 return ret; 118 } 119 120 /** 121 * acpi_amd_wbrf_add_remove - add or remove the frequency band the device is using 122 * 123 * @dev: device pointer 124 * @action: remove or add the frequency band into bios 125 * @in: input structure containing the frequency band the device is using 126 * 127 * Broadcast to other consumers the frequency band the device starts 128 * to use. Underneath the surface the information is cached into an 129 * internal buffer first. Then a notification is sent to all those 130 * registered consumers. So then they can retrieve that buffer to 131 * know the latest active frequency bands. Consumers that haven't 132 * yet been registered can retrieve the information from the cache 133 * when they register. 134 * 135 * Return: 136 * 0 for success add/remove wifi frequency band. 137 * Returns a negative error code for failure. 138 */ 139 int acpi_amd_wbrf_add_remove(struct device *dev, uint8_t action, struct wbrf_ranges_in_out *in) 140 { 141 struct acpi_device *adev; 142 int ret; 143 144 adev = ACPI_COMPANION(dev); 145 if (!adev) 146 return -ENODEV; 147 148 ret = wbrf_record(adev, action, in); 149 if (ret) 150 return ret; 151 152 blocking_notifier_call_chain(&wbrf_chain_head, WBRF_CHANGED, NULL); 153 154 return 0; 155 } 156 EXPORT_SYMBOL_GPL(acpi_amd_wbrf_add_remove); 157 158 /** 159 * acpi_amd_wbrf_supported_producer - determine if the WBRF can be enabled 160 * for the device as a producer 161 * 162 * @dev: device pointer 163 * 164 * Check if the platform equipped with necessary implementations to 165 * support WBRF for the device as a producer. 166 * 167 * Return: 168 * true if WBRF is supported, otherwise returns false 169 */ 170 bool acpi_amd_wbrf_supported_producer(struct device *dev) 171 { 172 struct acpi_device *adev; 173 174 adev = ACPI_COMPANION(dev); 175 if (!adev) 176 return false; 177 178 return acpi_check_dsm(adev->handle, &wifi_acpi_dsm_guid, 179 WBRF_REVISION, BIT(WBRF_RECORD)); 180 } 181 EXPORT_SYMBOL_GPL(acpi_amd_wbrf_supported_producer); 182 183 /** 184 * acpi_amd_wbrf_supported_consumer - determine if the WBRF can be enabled 185 * for the device as a consumer 186 * 187 * @dev: device pointer 188 * 189 * Determine if the platform equipped with necessary implementations to 190 * support WBRF for the device as a consumer. 191 * 192 * Return: 193 * true if WBRF is supported, otherwise returns false. 194 */ 195 bool acpi_amd_wbrf_supported_consumer(struct device *dev) 196 { 197 struct acpi_device *adev; 198 199 adev = ACPI_COMPANION(dev); 200 if (!adev) 201 return false; 202 203 return acpi_check_dsm(adev->handle, &wifi_acpi_dsm_guid, 204 WBRF_REVISION, BIT(WBRF_RETRIEVE)); 205 } 206 EXPORT_SYMBOL_GPL(acpi_amd_wbrf_supported_consumer); 207 208 /** 209 * amd_wbrf_retrieve_freq_band - retrieve current active frequency bands 210 * 211 * @dev: device pointer 212 * @out: output structure containing all the active frequency bands 213 * 214 * Retrieve the current active frequency bands which were broadcasted 215 * by other producers. The consumer who calls this API should take 216 * proper actions if any of the frequency band may cause RFI with its 217 * own frequency band used. 218 * 219 * Return: 220 * 0 for getting wifi freq band successfully. 221 * Returns a negative error code for failure. 222 */ 223 int amd_wbrf_retrieve_freq_band(struct device *dev, struct wbrf_ranges_in_out *out) 224 { 225 struct amd_wbrf_ranges_out acpi_out = {0}; 226 struct acpi_device *adev; 227 union acpi_object *obj; 228 union acpi_object param; 229 int ret = 0; 230 231 adev = ACPI_COMPANION(dev); 232 if (!adev) 233 return -ENODEV; 234 235 param.type = ACPI_TYPE_STRING; 236 param.string.length = 0; 237 param.string.pointer = NULL; 238 239 obj = acpi_evaluate_dsm(adev->handle, &wifi_acpi_dsm_guid, 240 WBRF_REVISION, WBRF_RETRIEVE, ¶m); 241 if (!obj) 242 return -EINVAL; 243 244 /* 245 * The return buffer is with variable length and the format below: 246 * number_of_entries(1 DWORD): Number of entries 247 * start_freq of 1st entry(1 QWORD): Start frequency of the 1st entry 248 * end_freq of 1st entry(1 QWORD): End frequency of the 1st entry 249 * ... 250 * ... 251 * start_freq of the last entry(1 QWORD) 252 * end_freq of the last entry(1 QWORD) 253 * 254 * Thus the buffer length is determined by the number of entries. 255 * - For zero entry scenario, the buffer length will be 4 bytes. 256 * - For one entry scenario, the buffer length will be 20 bytes. 257 */ 258 if (obj->buffer.length > sizeof(acpi_out) || obj->buffer.length < 4) { 259 dev_err(dev, "Wrong sized WBRT information"); 260 ret = -EINVAL; 261 goto out; 262 } 263 memcpy(&acpi_out, obj->buffer.pointer, obj->buffer.length); 264 265 out->num_of_ranges = acpi_out.num_of_ranges; 266 memcpy(out->band_list, acpi_out.band_list, sizeof(acpi_out.band_list)); 267 268 out: 269 ACPI_FREE(obj); 270 return ret; 271 } 272 EXPORT_SYMBOL_GPL(amd_wbrf_retrieve_freq_band); 273 274 /** 275 * amd_wbrf_register_notifier - register for notifications of frequency 276 * band update 277 * 278 * @nb: driver notifier block 279 * 280 * The consumer should register itself via this API so that it can get 281 * notified on the frequency band updates from other producers. 282 * 283 * Return: 284 * 0 for registering a consumer driver successfully. 285 * Returns a negative error code for failure. 286 */ 287 int amd_wbrf_register_notifier(struct notifier_block *nb) 288 { 289 return blocking_notifier_chain_register(&wbrf_chain_head, nb); 290 } 291 EXPORT_SYMBOL_GPL(amd_wbrf_register_notifier); 292 293 /** 294 * amd_wbrf_unregister_notifier - unregister for notifications of 295 * frequency band update 296 * 297 * @nb: driver notifier block 298 * 299 * The consumer should call this API when it is longer interested with 300 * the frequency band updates from other producers. Usually, this should 301 * be performed during driver cleanup. 302 * 303 * Return: 304 * 0 for unregistering a consumer driver. 305 * Returns a negative error code for failure. 306 */ 307 int amd_wbrf_unregister_notifier(struct notifier_block *nb) 308 { 309 return blocking_notifier_chain_unregister(&wbrf_chain_head, nb); 310 } 311 EXPORT_SYMBOL_GPL(amd_wbrf_unregister_notifier); 312