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 union acpi_object *tmp; 46 union acpi_object *obj; 47 u32 num_of_ranges = 0; 48 u32 num_of_elements; 49 u32 arg_idx = 0; 50 int ret; 51 u32 i; 52 53 if (!in) 54 return -EINVAL; 55 56 for (i = 0; i < ARRAY_SIZE(in->band_list); i++) { 57 if (in->band_list[i].start && in->band_list[i].end) 58 num_of_ranges++; 59 } 60 61 /* 62 * The num_of_ranges value in the "in" object supplied by 63 * the caller is required to be equal to the number of 64 * entries in the band_list array in there. 65 */ 66 if (num_of_ranges != in->num_of_ranges) 67 return -EINVAL; 68 69 /* 70 * Every input frequency band comes with two end points(start/end) 71 * and each is accounted as an element. Meanwhile the range count 72 * and action type are accounted as an element each. 73 * So, the total element count = 2 * num_of_ranges + 1 + 1. 74 */ 75 num_of_elements = 2 * num_of_ranges + 2; 76 77 tmp = kcalloc(num_of_elements, sizeof(*tmp), GFP_KERNEL); 78 if (!tmp) 79 return -ENOMEM; 80 81 argv4.package.type = ACPI_TYPE_PACKAGE; 82 argv4.package.count = num_of_elements; 83 argv4.package.elements = tmp; 84 85 /* save the number of ranges*/ 86 tmp[0].integer.type = ACPI_TYPE_INTEGER; 87 tmp[0].integer.value = num_of_ranges; 88 89 /* save the action(WBRF_RECORD_ADD/REMOVE/RETRIEVE) */ 90 tmp[1].integer.type = ACPI_TYPE_INTEGER; 91 tmp[1].integer.value = action; 92 93 arg_idx = 2; 94 for (i = 0; i < ARRAY_SIZE(in->band_list); i++) { 95 if (!in->band_list[i].start || !in->band_list[i].end) 96 continue; 97 98 tmp[arg_idx].integer.type = ACPI_TYPE_INTEGER; 99 tmp[arg_idx++].integer.value = in->band_list[i].start; 100 tmp[arg_idx].integer.type = ACPI_TYPE_INTEGER; 101 tmp[arg_idx++].integer.value = in->band_list[i].end; 102 } 103 104 obj = 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 ret = -EINVAL; 112 goto out; 113 } 114 115 ret = obj->integer.value; 116 if (ret) 117 ret = -EINVAL; 118 119 out: 120 ACPI_FREE(obj); 121 kfree(tmp); 122 123 return ret; 124 } 125 126 /** 127 * acpi_amd_wbrf_add_remove - add or remove the frequency band the device is using 128 * 129 * @dev: device pointer 130 * @action: remove or add the frequency band into bios 131 * @in: input structure containing the frequency band the device is using 132 * 133 * Broadcast to other consumers the frequency band the device starts 134 * to use. Underneath the surface the information is cached into an 135 * internal buffer first. Then a notification is sent to all those 136 * registered consumers. So then they can retrieve that buffer to 137 * know the latest active frequency bands. Consumers that haven't 138 * yet been registered can retrieve the information from the cache 139 * when they register. 140 * 141 * Return: 142 * 0 for success add/remove wifi frequency band. 143 * Returns a negative error code for failure. 144 */ 145 int acpi_amd_wbrf_add_remove(struct device *dev, uint8_t action, struct wbrf_ranges_in_out *in) 146 { 147 struct acpi_device *adev; 148 int ret; 149 150 adev = ACPI_COMPANION(dev); 151 if (!adev) 152 return -ENODEV; 153 154 ret = wbrf_record(adev, action, in); 155 if (ret) 156 return ret; 157 158 blocking_notifier_call_chain(&wbrf_chain_head, WBRF_CHANGED, NULL); 159 160 return 0; 161 } 162 EXPORT_SYMBOL_GPL(acpi_amd_wbrf_add_remove); 163 164 /** 165 * acpi_amd_wbrf_supported_producer - determine if the WBRF can be enabled 166 * for the device as a producer 167 * 168 * @dev: device pointer 169 * 170 * Check if the platform equipped with necessary implementations to 171 * support WBRF for the device as a producer. 172 * 173 * Return: 174 * true if WBRF is supported, otherwise returns false 175 */ 176 bool acpi_amd_wbrf_supported_producer(struct device *dev) 177 { 178 struct acpi_device *adev; 179 180 adev = ACPI_COMPANION(dev); 181 if (!adev) 182 return false; 183 184 return acpi_check_dsm(adev->handle, &wifi_acpi_dsm_guid, 185 WBRF_REVISION, BIT(WBRF_RECORD)); 186 } 187 EXPORT_SYMBOL_GPL(acpi_amd_wbrf_supported_producer); 188 189 /** 190 * acpi_amd_wbrf_supported_consumer - determine if the WBRF can be enabled 191 * for the device as a consumer 192 * 193 * @dev: device pointer 194 * 195 * Determine if the platform equipped with necessary implementations to 196 * support WBRF for the device as a consumer. 197 * 198 * Return: 199 * true if WBRF is supported, otherwise returns false. 200 */ 201 bool acpi_amd_wbrf_supported_consumer(struct device *dev) 202 { 203 struct acpi_device *adev; 204 205 adev = ACPI_COMPANION(dev); 206 if (!adev) 207 return false; 208 209 return acpi_check_dsm(adev->handle, &wifi_acpi_dsm_guid, 210 WBRF_REVISION, BIT(WBRF_RETRIEVE)); 211 } 212 EXPORT_SYMBOL_GPL(acpi_amd_wbrf_supported_consumer); 213 214 /** 215 * amd_wbrf_retrieve_freq_band - retrieve current active frequency bands 216 * 217 * @dev: device pointer 218 * @out: output structure containing all the active frequency bands 219 * 220 * Retrieve the current active frequency bands which were broadcasted 221 * by other producers. The consumer who calls this API should take 222 * proper actions if any of the frequency band may cause RFI with its 223 * own frequency band used. 224 * 225 * Return: 226 * 0 for getting wifi freq band successfully. 227 * Returns a negative error code for failure. 228 */ 229 int amd_wbrf_retrieve_freq_band(struct device *dev, struct wbrf_ranges_in_out *out) 230 { 231 struct amd_wbrf_ranges_out acpi_out = {0}; 232 struct acpi_device *adev; 233 union acpi_object *obj; 234 union acpi_object param; 235 int ret = 0; 236 237 adev = ACPI_COMPANION(dev); 238 if (!adev) 239 return -ENODEV; 240 241 param.type = ACPI_TYPE_STRING; 242 param.string.length = 0; 243 param.string.pointer = NULL; 244 245 obj = acpi_evaluate_dsm(adev->handle, &wifi_acpi_dsm_guid, 246 WBRF_REVISION, WBRF_RETRIEVE, ¶m); 247 if (!obj) 248 return -EINVAL; 249 250 /* 251 * The return buffer is with variable length and the format below: 252 * number_of_entries(1 DWORD): Number of entries 253 * start_freq of 1st entry(1 QWORD): Start frequency of the 1st entry 254 * end_freq of 1st entry(1 QWORD): End frequency of the 1st entry 255 * ... 256 * ... 257 * start_freq of the last entry(1 QWORD) 258 * end_freq of the last entry(1 QWORD) 259 * 260 * Thus the buffer length is determined by the number of entries. 261 * - For zero entry scenario, the buffer length will be 4 bytes. 262 * - For one entry scenario, the buffer length will be 20 bytes. 263 */ 264 if (obj->buffer.length > sizeof(acpi_out) || obj->buffer.length < 4) { 265 dev_err(dev, "Wrong sized WBRT information"); 266 ret = -EINVAL; 267 goto out; 268 } 269 memcpy(&acpi_out, obj->buffer.pointer, obj->buffer.length); 270 271 out->num_of_ranges = acpi_out.num_of_ranges; 272 memcpy(out->band_list, acpi_out.band_list, sizeof(acpi_out.band_list)); 273 274 out: 275 ACPI_FREE(obj); 276 return ret; 277 } 278 EXPORT_SYMBOL_GPL(amd_wbrf_retrieve_freq_band); 279 280 /** 281 * amd_wbrf_register_notifier - register for notifications of frequency 282 * band update 283 * 284 * @nb: driver notifier block 285 * 286 * The consumer should register itself via this API so that it can get 287 * notified on the frequency band updates from other producers. 288 * 289 * Return: 290 * 0 for registering a consumer driver successfully. 291 * Returns a negative error code for failure. 292 */ 293 int amd_wbrf_register_notifier(struct notifier_block *nb) 294 { 295 return blocking_notifier_chain_register(&wbrf_chain_head, nb); 296 } 297 EXPORT_SYMBOL_GPL(amd_wbrf_register_notifier); 298 299 /** 300 * amd_wbrf_unregister_notifier - unregister for notifications of 301 * frequency band update 302 * 303 * @nb: driver notifier block 304 * 305 * The consumer should call this API when it is longer interested with 306 * the frequency band updates from other producers. Usually, this should 307 * be performed during driver cleanup. 308 * 309 * Return: 310 * 0 for unregistering a consumer driver. 311 * Returns a negative error code for failure. 312 */ 313 int amd_wbrf_unregister_notifier(struct notifier_block *nb) 314 { 315 return blocking_notifier_chain_unregister(&wbrf_chain_head, nb); 316 } 317 EXPORT_SYMBOL_GPL(amd_wbrf_unregister_notifier); 318