1 // SPDX-License-Identifier: GPL-2.0-only
3 * ACPI helpers for DMA request / controller
7 * Copyright (C) 2013, Intel Corporation
8 * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
9 * Mika Westerberg <mika.westerberg@linux.intel.com>
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>
25 static LIST_HEAD(acpi_dma_list);
26 static DEFINE_MUTEX(acpi_dma_lock);
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
34 * In order to match a device from DSDT table to the corresponding CSRT device
35 * we use MMIO address and IRQ.
38 * 1 on success, 0 when no information is available, or appropriate errno value
41 static int acpi_dma_parse_resource_group(const struct acpi_csrt_group *grp,
42 struct acpi_device *adev, struct acpi_dma *adma)
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;
50 if (grp->shared_info_length != sizeof(struct acpi_csrt_shared_info))
53 INIT_LIST_HEAD(&resource_list);
54 ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
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;
65 acpi_dev_free_resource_list(&resource_list);
67 /* Consider initial zero values as resource not found */
68 if (mem == 0 && irq == 0)
71 si = (const struct acpi_csrt_shared_info *)&grp[1];
73 /* Match device by MMIO */
74 if (si->mmio_base_low != lower_32_bits(mem) ||
75 si->mmio_base_high != upper_32_bits(mem))
78 /* Match device by Linux vIRQ */
79 ret = acpi_register_gsi(NULL, si->gsi_interrupt, si->interrupt_mode, si->interrupt_polarity);
83 dev_dbg(&adev->dev, "matches with %.4s%04X (rev %u)\n",
84 (char *)&grp->vendor_id, grp->device_id, grp->revision);
86 /* Check if the request line range is available */
87 if (si->base_request_line == 0 && si->num_handshake_signals == 0)
90 /* Set up DMA mask based on value from CSRT */
91 ret = dma_coerce_mask_and_coherent(&adev->dev,
92 DMA_BIT_MASK(si->dma_address_width));
96 adma->base_request_line = si->base_request_line;
97 adma->end_request_line = si->base_request_line +
98 si->num_handshake_signals - 1;
100 dev_dbg(&adev->dev, "request line base: 0x%04x end: 0x%04x\n",
101 adma->base_request_line, adma->end_request_line);
107 * acpi_dma_parse_csrt - parse CSRT to exctract additional DMA resources
108 * @adev: ACPI device to match with
109 * @adma: struct acpi_dma of the given DMA controller
111 * CSRT or Core System Resources Table is a proprietary ACPI table
112 * introduced by Microsoft. This table can contain devices that are not in
113 * the system DSDT table. In particular DMA controllers might be described
116 * We are using this table to get the request line range of the specific DMA
117 * controller to be used later.
119 static void acpi_dma_parse_csrt(struct acpi_device *adev, struct acpi_dma *adma)
121 struct acpi_csrt_group *grp, *end;
122 struct acpi_table_csrt *csrt;
126 status = acpi_get_table(ACPI_SIG_CSRT, 0,
127 (struct acpi_table_header **)&csrt);
128 if (ACPI_FAILURE(status)) {
129 if (status != AE_NOT_FOUND)
130 dev_warn(&adev->dev, "failed to get the CSRT table\n");
134 grp = (struct acpi_csrt_group *)(csrt + 1);
135 end = (struct acpi_csrt_group *)((void *)csrt + csrt->header.length);
138 ret = acpi_dma_parse_resource_group(grp, adev, adma);
141 "error in parsing resource group\n");
145 grp = (struct acpi_csrt_group *)((void *)grp + grp->length);
148 acpi_put_table((struct acpi_table_header *)csrt);
152 * acpi_dma_controller_register - Register a DMA controller to ACPI DMA helpers
153 * @dev: struct device of DMA controller
154 * @acpi_dma_xlate: translation function which converts a dma specifier
155 * into a dma_chan structure
156 * @data: pointer to controller specific data to be used by
157 * translation function
159 * Allocated memory should be freed with appropriate acpi_dma_controller_free()
163 * 0 on success or appropriate errno value on error.
165 int acpi_dma_controller_register(struct device *dev,
166 struct dma_chan *(*acpi_dma_xlate)
167 (struct acpi_dma_spec *, struct acpi_dma *),
170 struct acpi_device *adev;
171 struct acpi_dma *adma;
173 if (!dev || !acpi_dma_xlate)
176 /* Check if the device was enumerated by ACPI */
177 adev = ACPI_COMPANION(dev);
181 adma = kzalloc(sizeof(*adma), GFP_KERNEL);
186 adma->acpi_dma_xlate = acpi_dma_xlate;
189 acpi_dma_parse_csrt(adev, adma);
191 /* Now queue acpi_dma controller structure in list */
192 mutex_lock(&acpi_dma_lock);
193 list_add_tail(&adma->dma_controllers, &acpi_dma_list);
194 mutex_unlock(&acpi_dma_lock);
198 EXPORT_SYMBOL_GPL(acpi_dma_controller_register);
201 * acpi_dma_controller_free - Remove a DMA controller from ACPI DMA helpers list
202 * @dev: struct device of DMA controller
204 * Memory allocated by acpi_dma_controller_register() is freed here.
207 * 0 on success or appropriate errno value on error.
209 int acpi_dma_controller_free(struct device *dev)
211 struct acpi_dma *adma;
216 mutex_lock(&acpi_dma_lock);
218 list_for_each_entry(adma, &acpi_dma_list, dma_controllers)
219 if (adma->dev == dev) {
220 list_del(&adma->dma_controllers);
221 mutex_unlock(&acpi_dma_lock);
226 mutex_unlock(&acpi_dma_lock);
229 EXPORT_SYMBOL_GPL(acpi_dma_controller_free);
231 static void devm_acpi_dma_release(struct device *dev, void *res)
233 acpi_dma_controller_free(dev);
237 * devm_acpi_dma_controller_register - resource managed acpi_dma_controller_register()
238 * @dev: device that is registering this DMA controller
239 * @acpi_dma_xlate: translation function
240 * @data: pointer to controller specific data
242 * Managed acpi_dma_controller_register(). DMA controller registered by this
243 * function are automatically freed on driver detach. See
244 * acpi_dma_controller_register() for more information.
247 * 0 on success or appropriate errno value on error.
249 int devm_acpi_dma_controller_register(struct device *dev,
250 struct dma_chan *(*acpi_dma_xlate)
251 (struct acpi_dma_spec *, struct acpi_dma *),
257 res = devres_alloc(devm_acpi_dma_release, 0, GFP_KERNEL);
261 ret = acpi_dma_controller_register(dev, acpi_dma_xlate, data);
266 devres_add(dev, res);
269 EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_register);
272 * devm_acpi_dma_controller_free - resource managed acpi_dma_controller_free()
273 * @dev: device that is unregistering as DMA controller
275 * Unregister a DMA controller registered with
276 * devm_acpi_dma_controller_register(). Normally this function will not need to
277 * be called and the resource management code will ensure that the resource is
280 void devm_acpi_dma_controller_free(struct device *dev)
282 WARN_ON(devres_release(dev, devm_acpi_dma_release, NULL, NULL));
284 EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free);
287 * acpi_dma_update_dma_spec - prepare dma specifier to pass to translation function
288 * @adma: struct acpi_dma of DMA controller
289 * @dma_spec: dma specifier to update
291 * Accordingly to ACPI 5.0 Specification Table 6-170 "Fixed DMA Resource
293 * DMA Request Line bits is a platform-relative number uniquely
294 * identifying the request line assigned. Request line-to-Controller
295 * mapping is done in a controller-specific OS driver.
296 * That's why we can safely adjust slave_id when the appropriate controller is
300 * 0, if no information is avaiable, -1 on mismatch, and 1 otherwise.
302 static int acpi_dma_update_dma_spec(struct acpi_dma *adma,
303 struct acpi_dma_spec *dma_spec)
305 /* Set link to the DMA controller device */
306 dma_spec->dev = adma->dev;
308 /* Check if the request line range is available */
309 if (adma->base_request_line == 0 && adma->end_request_line == 0)
312 /* Check if slave_id falls to the range */
313 if (dma_spec->slave_id < adma->base_request_line ||
314 dma_spec->slave_id > adma->end_request_line)
318 * Here we adjust slave_id. It should be a relative number to the base
321 dma_spec->slave_id -= adma->base_request_line;
326 struct acpi_dma_parser_data {
327 struct acpi_dma_spec dma_spec;
333 * acpi_dma_parse_fixed_dma - Parse FixedDMA ACPI resources to a DMA specifier
334 * @res: struct acpi_resource to get FixedDMA resources from
335 * @data: pointer to a helper struct acpi_dma_parser_data
337 static int acpi_dma_parse_fixed_dma(struct acpi_resource *res, void *data)
339 struct acpi_dma_parser_data *pdata = data;
341 if (res->type == ACPI_RESOURCE_TYPE_FIXED_DMA) {
342 struct acpi_resource_fixed_dma *dma = &res->data.fixed_dma;
344 if (pdata->n++ == pdata->index) {
345 pdata->dma_spec.chan_id = dma->channels;
346 pdata->dma_spec.slave_id = dma->request_lines;
350 /* Tell the ACPI core to skip this resource */
355 * acpi_dma_request_slave_chan_by_index - Get the DMA slave channel
356 * @dev: struct device to get DMA request from
357 * @index: index of FixedDMA descriptor for @dev
360 * Pointer to appropriate dma channel on success or an error pointer.
362 struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
365 struct acpi_dma_parser_data pdata;
366 struct acpi_dma_spec *dma_spec = &pdata.dma_spec;
367 struct acpi_device *adev = ACPI_COMPANION(dev);
368 struct list_head resource_list;
369 struct acpi_dma *adma;
370 struct dma_chan *chan = NULL;
374 memset(&pdata, 0, sizeof(pdata));
377 /* Initial values for the request line and channel */
378 dma_spec->chan_id = -1;
379 dma_spec->slave_id = -1;
381 INIT_LIST_HEAD(&resource_list);
382 ret = acpi_dev_get_resources(adev, &resource_list,
383 acpi_dma_parse_fixed_dma, &pdata);
384 acpi_dev_free_resource_list(&resource_list);
388 if (dma_spec->slave_id < 0 || dma_spec->chan_id < 0)
389 return ERR_PTR(-ENODEV);
391 mutex_lock(&acpi_dma_lock);
393 list_for_each_entry(adma, &acpi_dma_list, dma_controllers) {
395 * We are not going to call translation function if slave_id
396 * doesn't fall to the request range.
398 found = acpi_dma_update_dma_spec(adma, dma_spec);
401 chan = adma->acpi_dma_xlate(dma_spec, adma);
403 * Try to get a channel only from the DMA controller that
404 * matches the slave_id. See acpi_dma_update_dma_spec()
405 * description for the details.
407 if (found > 0 || chan)
411 mutex_unlock(&acpi_dma_lock);
412 return chan ? chan : ERR_PTR(-EPROBE_DEFER);
414 EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index);
417 * acpi_dma_request_slave_chan_by_name - Get the DMA slave channel
418 * @dev: struct device to get DMA request from
419 * @name: represents corresponding FixedDMA descriptor for @dev
421 * In order to support both Device Tree and ACPI in a single driver we
422 * translate the names "tx" and "rx" here based on the most common case where
423 * the first FixedDMA descriptor is TX and second is RX.
425 * If the device has "dma-names" property the FixedDMA descriptor indices
426 * are retrieved based on those. Otherwise the function falls back using
430 * Pointer to appropriate dma channel on success or an error pointer.
432 struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev,
437 index = device_property_match_string(dev, "dma-names", name);
439 if (!strcmp(name, "tx"))
441 else if (!strcmp(name, "rx"))
444 return ERR_PTR(-ENODEV);
447 dev_dbg(dev, "Looking for DMA channel \"%s\" at index %d...\n", name, index);
448 return acpi_dma_request_slave_chan_by_index(dev, index);
450 EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_name);
453 * acpi_dma_simple_xlate - Simple ACPI DMA engine translation helper
454 * @dma_spec: pointer to ACPI DMA specifier
455 * @adma: pointer to ACPI DMA controller data
457 * A simple translation function for ACPI based devices. Passes &struct
458 * dma_spec to the DMA controller driver provided filter function.
461 * Pointer to the channel if found or %NULL otherwise.
463 struct dma_chan *acpi_dma_simple_xlate(struct acpi_dma_spec *dma_spec,
464 struct acpi_dma *adma)
466 struct acpi_dma_filter_info *info = adma->data;
468 if (!info || !info->filter_fn)
471 return dma_request_channel(info->dma_cap, info->filter_fn, dma_spec);
473 EXPORT_SYMBOL_GPL(acpi_dma_simple_xlate);