acpi-dma.c 13 KB

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