1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * ACPI helpers for DMA request / controller 4 * 5 * Based on of-dma.c 6 * 7 * Copyright (C) 2013, Intel Corporation 8 * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com> 9 * Mika Westerberg <mika.westerberg@linux.intel.com> 10 */ 11 12#include <linux/device.h> 13#include <linux/dma-mapping.h> 14#include <linux/err.h> 15#include <linux/module.h> 16#include <linux/kernel.h> 17#include <linux/list.h> 18#include <linux/mutex.h> 19#include <linux/slab.h> 20#include <linux/ioport.h> 21#include <linux/acpi.h> 22#include <linux/acpi_dma.h> 23#include <linux/property.h> 24 25static LIST_HEAD(acpi_dma_list); 26static DEFINE_MUTEX(acpi_dma_lock); 27 28/** 29 * acpi_dma_parse_resource_group - match device and parse resource group 30 * @grp: CSRT resource group 31 * @adev: ACPI device to match with 32 * @adma: struct acpi_dma of the given DMA controller 33 * 34 * In order to match a device from DSDT table to the corresponding CSRT device 35 * we use MMIO address and IRQ. 36 * 37 * Return: 38 * 1 on success, 0 when no information is available, or appropriate errno value 39 * on error. 40 */ 41static int acpi_dma_parse_resource_group(const struct acpi_csrt_group *grp, 42 struct acpi_device *adev, struct acpi_dma *adma) 43{ 44 const struct acpi_csrt_shared_info *si; 45 struct list_head resource_list; 46 struct resource_entry *rentry; 47 resource_size_t mem = 0, irq = 0; 48 int ret; 49 50 if (grp->shared_info_length != sizeof(struct acpi_csrt_shared_info)) 51 return -ENODEV; 52 53 INIT_LIST_HEAD(&resource_list); 54 ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL); 55 if (ret <= 0) 56 return 0; 57 58 list_for_each_entry(rentry, &resource_list, node) { 59 if (resource_type(rentry->res) == IORESOURCE_MEM) 60 mem = rentry->res->start; 61 else if (resource_type(rentry->res) == IORESOURCE_IRQ) 62 irq = rentry->res->start; 63 } 64 65 acpi_dev_free_resource_list(&resource_list); 66 67 /* Consider initial zero values as resource not found */ 68 if (mem == 0 && irq == 0) 69 return 0; 70 71 si = (const struct acpi_csrt_shared_info *)&grp[1]; 72 73 /* Match device by MMIO */ 74 if (si->mmio_base_low != lower_32_bits(mem) || 75 si->mmio_base_high != upper_32_bits(mem)) 76 return 0; 77 78 /* 79 * acpi_gsi_to_irq() can't be used because some platforms do not save 80 * registered IRQs in the MP table. Instead we just try to register 81 * the GSI, which is the core part of the above mentioned function. 82 */ 83 ret = acpi_register_gsi(NULL, si->gsi_interrupt, si->interrupt_mode, si->interrupt_polarity); 84 if (ret < 0) 85 return 0; 86 87 /* Match device by Linux vIRQ */ 88 if (ret != irq) 89 return 0; 90 91 dev_dbg(&adev->dev, "matches with %.4s%04X (rev %u)\n", 92 (char *)&grp->vendor_id, grp->device_id, grp->revision); 93 94 /* Check if the request line range is available */ 95 if (si->base_request_line == 0 && si->num_handshake_signals == 0) 96 return 0; 97 98 /* Set up DMA mask based on value from CSRT */ 99 ret = dma_coerce_mask_and_coherent(&adev->dev, 100 DMA_BIT_MASK(si->dma_address_width)); 101 if (ret) 102 return 0; 103 104 adma->base_request_line = si->base_request_line; 105 adma->end_request_line = si->base_request_line + 106 si->num_handshake_signals - 1; 107 108 dev_dbg(&adev->dev, "request line base: 0x%04x end: 0x%04x\n", 109 adma->base_request_line, adma->end_request_line); 110 111 return 1; 112} 113 114/** 115 * acpi_dma_parse_csrt - parse CSRT to exctract additional DMA resources 116 * @adev: ACPI device to match with 117 * @adma: struct acpi_dma of the given DMA controller 118 * 119 * CSRT or Core System Resources Table is a proprietary ACPI table 120 * introduced by Microsoft. This table can contain devices that are not in 121 * the system DSDT table. In particular DMA controllers might be described 122 * here. 123 * 124 * We are using this table to get the request line range of the specific DMA 125 * controller to be used later. 126 */ 127static void acpi_dma_parse_csrt(struct acpi_device *adev, struct acpi_dma *adma) 128{ 129 struct acpi_csrt_group *grp, *end; 130 struct acpi_table_csrt *csrt; 131 acpi_status status; 132 int ret; 133 134 status = acpi_get_table(ACPI_SIG_CSRT, 0, 135 (struct acpi_table_header **)&csrt); 136 if (ACPI_FAILURE(status)) { 137 if (status != AE_NOT_FOUND) 138 dev_warn(&adev->dev, "failed to get the CSRT table\n"); 139 return; 140 } 141 142 grp = (struct acpi_csrt_group *)(csrt + 1); 143 end = (struct acpi_csrt_group *)((void *)csrt + csrt->header.length); 144 145 while (grp < end) { 146 ret = acpi_dma_parse_resource_group(grp, adev, adma); 147 if (ret < 0) { 148 dev_warn(&adev->dev, 149 "error in parsing resource group\n"); 150 break; 151 } 152 153 grp = (struct acpi_csrt_group *)((void *)grp + grp->length); 154 } 155 156 acpi_put_table((struct acpi_table_header *)csrt); 157} 158 159/** 160 * acpi_dma_controller_register - Register a DMA controller to ACPI DMA helpers 161 * @dev: struct device of DMA controller 162 * @acpi_dma_xlate: translation function which converts a dma specifier 163 * into a dma_chan structure 164 * @data: pointer to controller specific data to be used by 165 * translation function 166 * 167 * Allocated memory should be freed with appropriate acpi_dma_controller_free() 168 * call. 169 * 170 * Return: 171 * 0 on success or appropriate errno value on error. 172 */ 173int acpi_dma_controller_register(struct device *dev, 174 struct dma_chan *(*acpi_dma_xlate) 175 (struct acpi_dma_spec *, struct acpi_dma *), 176 void *data) 177{ 178 struct acpi_device *adev; 179 struct acpi_dma *adma; 180 181 if (!dev || !acpi_dma_xlate) 182 return -EINVAL; 183 184 /* Check if the device was enumerated by ACPI */ 185 adev = ACPI_COMPANION(dev); 186 if (!adev) 187 return -EINVAL; 188 189 adma = kzalloc(sizeof(*adma), GFP_KERNEL); 190 if (!adma) 191 return -ENOMEM; 192 193 adma->dev = dev; 194 adma->acpi_dma_xlate = acpi_dma_xlate; 195 adma->data = data; 196 197 acpi_dma_parse_csrt(adev, adma); 198 199 /* Now queue acpi_dma controller structure in list */ 200 mutex_lock(&acpi_dma_lock); 201 list_add_tail(&adma->dma_controllers, &acpi_dma_list); 202 mutex_unlock(&acpi_dma_lock); 203 204 return 0; 205} 206EXPORT_SYMBOL_GPL(acpi_dma_controller_register); 207 208/** 209 * acpi_dma_controller_free - Remove a DMA controller from ACPI DMA helpers list 210 * @dev: struct device of DMA controller 211 * 212 * Memory allocated by acpi_dma_controller_register() is freed here. 213 * 214 * Return: 215 * 0 on success or appropriate errno value on error. 216 */ 217int acpi_dma_controller_free(struct device *dev) 218{ 219 struct acpi_dma *adma; 220 221 if (!dev) 222 return -EINVAL; 223 224 mutex_lock(&acpi_dma_lock); 225 226 list_for_each_entry(adma, &acpi_dma_list, dma_controllers) 227 if (adma->dev == dev) { 228 list_del(&adma->dma_controllers); 229 mutex_unlock(&acpi_dma_lock); 230 kfree(adma); 231 return 0; 232 } 233 234 mutex_unlock(&acpi_dma_lock); 235 return -ENODEV; 236} 237EXPORT_SYMBOL_GPL(acpi_dma_controller_free); 238 239static void devm_acpi_dma_release(struct device *dev, void *res) 240{ 241 acpi_dma_controller_free(dev); 242} 243 244/** 245 * devm_acpi_dma_controller_register - resource managed acpi_dma_controller_register() 246 * @dev: device that is registering this DMA controller 247 * @acpi_dma_xlate: translation function 248 * @data: pointer to controller specific data 249 * 250 * Managed acpi_dma_controller_register(). DMA controller registered by this 251 * function are automatically freed on driver detach. See 252 * acpi_dma_controller_register() for more information. 253 * 254 * Return: 255 * 0 on success or appropriate errno value on error. 256 */ 257int devm_acpi_dma_controller_register(struct device *dev, 258 struct dma_chan *(*acpi_dma_xlate) 259 (struct acpi_dma_spec *, struct acpi_dma *), 260 void *data) 261{ 262 void *res; 263 int ret; 264 265 res = devres_alloc(devm_acpi_dma_release, 0, GFP_KERNEL); 266 if (!res) 267 return -ENOMEM; 268 269 ret = acpi_dma_controller_register(dev, acpi_dma_xlate, data); 270 if (ret) { 271 devres_free(res); 272 return ret; 273 } 274 devres_add(dev, res); 275 return 0; 276} 277EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_register); 278 279/** 280 * devm_acpi_dma_controller_free - resource managed acpi_dma_controller_free() 281 * @dev: device that is unregistering as DMA controller 282 * 283 * Unregister a DMA controller registered with 284 * devm_acpi_dma_controller_register(). Normally this function will not need to 285 * be called and the resource management code will ensure that the resource is 286 * freed. 287 */ 288void devm_acpi_dma_controller_free(struct device *dev) 289{ 290 WARN_ON(devres_release(dev, devm_acpi_dma_release, NULL, NULL)); 291} 292EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free); 293 294/** 295 * acpi_dma_update_dma_spec - prepare dma specifier to pass to translation function 296 * @adma: struct acpi_dma of DMA controller 297 * @dma_spec: dma specifier to update 298 * 299 * Accordingly to ACPI 5.0 Specification Table 6-170 "Fixed DMA Resource 300 * Descriptor": 301 * DMA Request Line bits is a platform-relative number uniquely 302 * identifying the request line assigned. Request line-to-Controller 303 * mapping is done in a controller-specific OS driver. 304 * That's why we can safely adjust slave_id when the appropriate controller is 305 * found. 306 * 307 * Return: 308 * 0, if no information is avaiable, -1 on mismatch, and 1 otherwise. 309 */ 310static int acpi_dma_update_dma_spec(struct acpi_dma *adma, 311 struct acpi_dma_spec *dma_spec) 312{ 313 /* Set link to the DMA controller device */ 314 dma_spec->dev = adma->dev; 315 316 /* Check if the request line range is available */ 317 if (adma->base_request_line == 0 && adma->end_request_line == 0) 318 return 0; 319 320 /* Check if slave_id falls to the range */ 321 if (dma_spec->slave_id < adma->base_request_line || 322 dma_spec->slave_id > adma->end_request_line) 323 return -1; 324 325 /* 326 * Here we adjust slave_id. It should be a relative number to the base 327 * request line. 328 */ 329 dma_spec->slave_id -= adma->base_request_line; 330 331 return 1; 332} 333 334struct acpi_dma_parser_data { 335 struct acpi_dma_spec dma_spec; 336 size_t index; 337 size_t n; 338}; 339 340/** 341 * acpi_dma_parse_fixed_dma - Parse FixedDMA ACPI resources to a DMA specifier 342 * @res: struct acpi_resource to get FixedDMA resources from 343 * @data: pointer to a helper struct acpi_dma_parser_data 344 */ 345static int acpi_dma_parse_fixed_dma(struct acpi_resource *res, void *data) 346{ 347 struct acpi_dma_parser_data *pdata = data; 348 349 if (res->type == ACPI_RESOURCE_TYPE_FIXED_DMA) { 350 struct acpi_resource_fixed_dma *dma = &res->data.fixed_dma; 351 352 if (pdata->n++ == pdata->index) { 353 pdata->dma_spec.chan_id = dma->channels; 354 pdata->dma_spec.slave_id = dma->request_lines; 355 } 356 } 357 358 /* Tell the ACPI core to skip this resource */ 359 return 1; 360} 361 362/** 363 * acpi_dma_request_slave_chan_by_index - Get the DMA slave channel 364 * @dev: struct device to get DMA request from 365 * @index: index of FixedDMA descriptor for @dev 366 * 367 * Return: 368 * Pointer to appropriate dma channel on success or an error pointer. 369 */ 370struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev, 371 size_t index) 372{ 373 struct acpi_dma_parser_data pdata; 374 struct acpi_dma_spec *dma_spec = &pdata.dma_spec; 375 struct acpi_device *adev = ACPI_COMPANION(dev); 376 struct list_head resource_list; 377 struct acpi_dma *adma; 378 struct dma_chan *chan = NULL; 379 int found; 380 int ret; 381 382 memset(&pdata, 0, sizeof(pdata)); 383 pdata.index = index; 384 385 /* Initial values for the request line and channel */ 386 dma_spec->chan_id = -1; 387 dma_spec->slave_id = -1; 388 389 INIT_LIST_HEAD(&resource_list); 390 ret = acpi_dev_get_resources(adev, &resource_list, 391 acpi_dma_parse_fixed_dma, &pdata); 392 acpi_dev_free_resource_list(&resource_list); 393 if (ret < 0) 394 return ERR_PTR(ret); 395 396 if (dma_spec->slave_id < 0 || dma_spec->chan_id < 0) 397 return ERR_PTR(-ENODEV); 398 399 mutex_lock(&acpi_dma_lock); 400 401 list_for_each_entry(adma, &acpi_dma_list, dma_controllers) { 402 /* 403 * We are not going to call translation function if slave_id 404 * doesn't fall to the request range. 405 */ 406 found = acpi_dma_update_dma_spec(adma, dma_spec); 407 if (found < 0) 408 continue; 409 chan = adma->acpi_dma_xlate(dma_spec, adma); 410 /* 411 * Try to get a channel only from the DMA controller that 412 * matches the slave_id. See acpi_dma_update_dma_spec() 413 * description for the details. 414 */ 415 if (found > 0 || chan) 416 break; 417 } 418 419 mutex_unlock(&acpi_dma_lock); 420 return chan ? chan : ERR_PTR(-EPROBE_DEFER); 421} 422EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index); 423 424/** 425 * acpi_dma_request_slave_chan_by_name - Get the DMA slave channel 426 * @dev: struct device to get DMA request from 427 * @name: represents corresponding FixedDMA descriptor for @dev 428 * 429 * In order to support both Device Tree and ACPI in a single driver we 430 * translate the names "tx" and "rx" here based on the most common case where 431 * the first FixedDMA descriptor is TX and second is RX. 432 * 433 * If the device has "dma-names" property the FixedDMA descriptor indices 434 * are retrieved based on those. Otherwise the function falls back using 435 * hardcoded indices. 436 * 437 * Return: 438 * Pointer to appropriate dma channel on success or an error pointer. 439 */ 440struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev, 441 const char *name) 442{ 443 int index; 444 445 index = device_property_match_string(dev, "dma-names", name); 446 if (index < 0) { 447 if (!strcmp(name, "tx")) 448 index = 0; 449 else if (!strcmp(name, "rx")) 450 index = 1; 451 else 452 return ERR_PTR(-ENODEV); 453 } 454 455 dev_dbg(dev, "Looking for DMA channel \"%s\" at index %d...\n", name, index); 456 return acpi_dma_request_slave_chan_by_index(dev, index); 457} 458EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_name); 459 460/** 461 * acpi_dma_simple_xlate - Simple ACPI DMA engine translation helper 462 * @dma_spec: pointer to ACPI DMA specifier 463 * @adma: pointer to ACPI DMA controller data 464 * 465 * A simple translation function for ACPI based devices. Passes &struct 466 * dma_spec to the DMA controller driver provided filter function. 467 * 468 * Return: 469 * Pointer to the channel if found or %NULL otherwise. 470 */ 471struct dma_chan *acpi_dma_simple_xlate(struct acpi_dma_spec *dma_spec, 472 struct acpi_dma *adma) 473{ 474 struct acpi_dma_filter_info *info = adma->data; 475 476 if (!info || !info->filter_fn) 477 return NULL; 478 479 return dma_request_channel(info->dma_cap, info->filter_fn, dma_spec); 480} 481EXPORT_SYMBOL_GPL(acpi_dma_simple_xlate); 482