2 * ACPI helpers for DMA request / controller
6 * Copyright (C) 2013, Intel Corporation
7 * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
8 * Mika Westerberg <mika.westerberg@linux.intel.com>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
15 #include <linux/device.h>
16 #include <linux/err.h>
17 #include <linux/module.h>
18 #include <linux/kernel.h>
19 #include <linux/list.h>
20 #include <linux/mutex.h>
21 #include <linux/slab.h>
22 #include <linux/ioport.h>
23 #include <linux/acpi.h>
24 #include <linux/acpi_dma.h>
25 #include <linux/property.h>
27 static LIST_HEAD(acpi_dma_list);
28 static DEFINE_MUTEX(acpi_dma_lock);
31 * acpi_dma_parse_resource_group - match device and parse resource group
32 * @grp: CSRT resource group
33 * @adev: ACPI device to match with
34 * @adma: struct acpi_dma of the given DMA controller
36 * In order to match a device from DSDT table to the corresponding CSRT device
37 * we use MMIO address and IRQ.
40 * 1 on success, 0 when no information is available, or appropriate errno value
43 static int acpi_dma_parse_resource_group(const struct acpi_csrt_group *grp,
44 struct acpi_device *adev, struct acpi_dma *adma)
46 const struct acpi_csrt_shared_info *si;
47 struct list_head resource_list;
48 struct resource_entry *rentry;
49 resource_size_t mem = 0, irq = 0;
52 if (grp->shared_info_length != sizeof(struct acpi_csrt_shared_info))
55 INIT_LIST_HEAD(&resource_list);
56 ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
60 list_for_each_entry(rentry, &resource_list, node) {
61 if (resource_type(rentry->res) == IORESOURCE_MEM)
62 mem = rentry->res->start;
63 else if (resource_type(rentry->res) == IORESOURCE_IRQ)
64 irq = rentry->res->start;
67 acpi_dev_free_resource_list(&resource_list);
69 /* Consider initial zero values as resource not found */
70 if (mem == 0 && irq == 0)
73 si = (const struct acpi_csrt_shared_info *)&grp[1];
75 /* Match device by MMIO and IRQ */
76 if (si->mmio_base_low != lower_32_bits(mem) ||
77 si->mmio_base_high != upper_32_bits(mem) ||
78 si->gsi_interrupt != irq)
81 dev_dbg(&adev->dev, "matches with %.4s%04X (rev %u)\n",
82 (char *)&grp->vendor_id, grp->device_id, grp->revision);
84 /* Check if the request line range is available */
85 if (si->base_request_line == 0 && si->num_handshake_signals == 0)
88 adma->base_request_line = si->base_request_line;
89 adma->end_request_line = si->base_request_line +
90 si->num_handshake_signals - 1;
92 dev_dbg(&adev->dev, "request line base: 0x%04x end: 0x%04x\n",
93 adma->base_request_line, adma->end_request_line);
99 * acpi_dma_parse_csrt - parse CSRT to exctract additional DMA resources
100 * @adev: ACPI device to match with
101 * @adma: struct acpi_dma of the given DMA controller
103 * CSRT or Core System Resources Table is a proprietary ACPI table
104 * introduced by Microsoft. This table can contain devices that are not in
105 * the system DSDT table. In particular DMA controllers might be described
108 * We are using this table to get the request line range of the specific DMA
109 * controller to be used later.
111 static void acpi_dma_parse_csrt(struct acpi_device *adev, struct acpi_dma *adma)
113 struct acpi_csrt_group *grp, *end;
114 struct acpi_table_csrt *csrt;
118 status = acpi_get_table(ACPI_SIG_CSRT, 0,
119 (struct acpi_table_header **)&csrt);
120 if (ACPI_FAILURE(status)) {
121 if (status != AE_NOT_FOUND)
122 dev_warn(&adev->dev, "failed to get the CSRT table\n");
126 grp = (struct acpi_csrt_group *)(csrt + 1);
127 end = (struct acpi_csrt_group *)((void *)csrt + csrt->header.length);
130 ret = acpi_dma_parse_resource_group(grp, adev, adma);
133 "error in parsing resource group\n");
137 grp = (struct acpi_csrt_group *)((void *)grp + grp->length);
140 acpi_put_table((struct acpi_table_header *)csrt);
144 * acpi_dma_controller_register - Register a DMA controller to ACPI DMA helpers
145 * @dev: struct device of DMA controller
146 * @acpi_dma_xlate: translation function which converts a dma specifier
147 * into a dma_chan structure
148 * @data pointer to controller specific data to be used by
149 * translation function
151 * Allocated memory should be freed with appropriate acpi_dma_controller_free()
155 * 0 on success or appropriate errno value on error.
157 int acpi_dma_controller_register(struct device *dev,
158 struct dma_chan *(*acpi_dma_xlate)
159 (struct acpi_dma_spec *, struct acpi_dma *),
162 struct acpi_device *adev;
163 struct acpi_dma *adma;
165 if (!dev || !acpi_dma_xlate)
168 /* Check if the device was enumerated by ACPI */
169 adev = ACPI_COMPANION(dev);
173 adma = kzalloc(sizeof(*adma), GFP_KERNEL);
178 adma->acpi_dma_xlate = acpi_dma_xlate;
181 acpi_dma_parse_csrt(adev, adma);
183 /* Now queue acpi_dma controller structure in list */
184 mutex_lock(&acpi_dma_lock);
185 list_add_tail(&adma->dma_controllers, &acpi_dma_list);
186 mutex_unlock(&acpi_dma_lock);
190 EXPORT_SYMBOL_GPL(acpi_dma_controller_register);
193 * acpi_dma_controller_free - Remove a DMA controller from ACPI DMA helpers list
194 * @dev: struct device of DMA controller
196 * Memory allocated by acpi_dma_controller_register() is freed here.
199 * 0 on success or appropriate errno value on error.
201 int acpi_dma_controller_free(struct device *dev)
203 struct acpi_dma *adma;
208 mutex_lock(&acpi_dma_lock);
210 list_for_each_entry(adma, &acpi_dma_list, dma_controllers)
211 if (adma->dev == dev) {
212 list_del(&adma->dma_controllers);
213 mutex_unlock(&acpi_dma_lock);
218 mutex_unlock(&acpi_dma_lock);
221 EXPORT_SYMBOL_GPL(acpi_dma_controller_free);
223 static void devm_acpi_dma_release(struct device *dev, void *res)
225 acpi_dma_controller_free(dev);
229 * devm_acpi_dma_controller_register - resource managed acpi_dma_controller_register()
230 * @dev: device that is registering this DMA controller
231 * @acpi_dma_xlate: translation function
232 * @data pointer to controller specific data
234 * Managed acpi_dma_controller_register(). DMA controller registered by this
235 * function are automatically freed on driver detach. See
236 * acpi_dma_controller_register() for more information.
239 * 0 on success or appropriate errno value on error.
241 int devm_acpi_dma_controller_register(struct device *dev,
242 struct dma_chan *(*acpi_dma_xlate)
243 (struct acpi_dma_spec *, struct acpi_dma *),
249 res = devres_alloc(devm_acpi_dma_release, 0, GFP_KERNEL);
253 ret = acpi_dma_controller_register(dev, acpi_dma_xlate, data);
258 devres_add(dev, res);
261 EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_register);
264 * devm_acpi_dma_controller_free - resource managed acpi_dma_controller_free()
266 * Unregister a DMA controller registered with
267 * devm_acpi_dma_controller_register(). Normally this function will not need to
268 * be called and the resource management code will ensure that the resource is
271 void devm_acpi_dma_controller_free(struct device *dev)
273 WARN_ON(devres_release(dev, devm_acpi_dma_release, NULL, NULL));
275 EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free);
278 * acpi_dma_update_dma_spec - prepare dma specifier to pass to translation function
279 * @adma: struct acpi_dma of DMA controller
280 * @dma_spec: dma specifier to update
282 * Accordingly to ACPI 5.0 Specification Table 6-170 "Fixed DMA Resource
284 * DMA Request Line bits is a platform-relative number uniquely
285 * identifying the request line assigned. Request line-to-Controller
286 * mapping is done in a controller-specific OS driver.
287 * That's why we can safely adjust slave_id when the appropriate controller is
291 * 0, if no information is avaiable, -1 on mismatch, and 1 otherwise.
293 static int acpi_dma_update_dma_spec(struct acpi_dma *adma,
294 struct acpi_dma_spec *dma_spec)
296 /* Set link to the DMA controller device */
297 dma_spec->dev = adma->dev;
299 /* Check if the request line range is available */
300 if (adma->base_request_line == 0 && adma->end_request_line == 0)
303 /* Check if slave_id falls to the range */
304 if (dma_spec->slave_id < adma->base_request_line ||
305 dma_spec->slave_id > adma->end_request_line)
309 * Here we adjust slave_id. It should be a relative number to the base
312 dma_spec->slave_id -= adma->base_request_line;
317 struct acpi_dma_parser_data {
318 struct acpi_dma_spec dma_spec;
324 * acpi_dma_parse_fixed_dma - Parse FixedDMA ACPI resources to a DMA specifier
325 * @res: struct acpi_resource to get FixedDMA resources from
326 * @data: pointer to a helper struct acpi_dma_parser_data
328 static int acpi_dma_parse_fixed_dma(struct acpi_resource *res, void *data)
330 struct acpi_dma_parser_data *pdata = data;
332 if (res->type == ACPI_RESOURCE_TYPE_FIXED_DMA) {
333 struct acpi_resource_fixed_dma *dma = &res->data.fixed_dma;
335 if (pdata->n++ == pdata->index) {
336 pdata->dma_spec.chan_id = dma->channels;
337 pdata->dma_spec.slave_id = dma->request_lines;
341 /* Tell the ACPI core to skip this resource */
346 * acpi_dma_request_slave_chan_by_index - Get the DMA slave channel
347 * @dev: struct device to get DMA request from
348 * @index: index of FixedDMA descriptor for @dev
351 * Pointer to appropriate dma channel on success or an error pointer.
353 struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
356 struct acpi_dma_parser_data pdata;
357 struct acpi_dma_spec *dma_spec = &pdata.dma_spec;
358 struct list_head resource_list;
359 struct acpi_device *adev;
360 struct acpi_dma *adma;
361 struct dma_chan *chan = NULL;
364 /* Check if the device was enumerated by ACPI */
366 return ERR_PTR(-ENODEV);
368 adev = ACPI_COMPANION(dev);
370 return ERR_PTR(-ENODEV);
372 memset(&pdata, 0, sizeof(pdata));
375 /* Initial values for the request line and channel */
376 dma_spec->chan_id = -1;
377 dma_spec->slave_id = -1;
379 INIT_LIST_HEAD(&resource_list);
380 acpi_dev_get_resources(adev, &resource_list,
381 acpi_dma_parse_fixed_dma, &pdata);
382 acpi_dev_free_resource_list(&resource_list);
384 if (dma_spec->slave_id < 0 || dma_spec->chan_id < 0)
385 return ERR_PTR(-ENODEV);
387 mutex_lock(&acpi_dma_lock);
389 list_for_each_entry(adma, &acpi_dma_list, dma_controllers) {
391 * We are not going to call translation function if slave_id
392 * doesn't fall to the request range.
394 found = acpi_dma_update_dma_spec(adma, dma_spec);
397 chan = adma->acpi_dma_xlate(dma_spec, adma);
399 * Try to get a channel only from the DMA controller that
400 * matches the slave_id. See acpi_dma_update_dma_spec()
401 * description for the details.
403 if (found > 0 || chan)
407 mutex_unlock(&acpi_dma_lock);
408 return chan ? chan : ERR_PTR(-EPROBE_DEFER);
410 EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index);
413 * acpi_dma_request_slave_chan_by_name - Get the DMA slave channel
414 * @dev: struct device to get DMA request from
415 * @name: represents corresponding FixedDMA descriptor for @dev
417 * In order to support both Device Tree and ACPI in a single driver we
418 * translate the names "tx" and "rx" here based on the most common case where
419 * the first FixedDMA descriptor is TX and second is RX.
421 * If the device has "dma-names" property the FixedDMA descriptor indices
422 * are retrieved based on those. Otherwise the function falls back using
426 * Pointer to appropriate dma channel on success or an error pointer.
428 struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev,
433 index = device_property_match_string(dev, "dma-names", name);
435 if (!strcmp(name, "tx"))
437 else if (!strcmp(name, "rx"))
440 return ERR_PTR(-ENODEV);
443 dev_dbg(dev, "Looking for DMA channel \"%s\" at index %d...\n", name, index);
444 return acpi_dma_request_slave_chan_by_index(dev, index);
446 EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_name);
449 * acpi_dma_simple_xlate - Simple ACPI DMA engine translation helper
450 * @dma_spec: pointer to ACPI DMA specifier
451 * @adma: pointer to ACPI DMA controller data
453 * A simple translation function for ACPI based devices. Passes &struct
454 * dma_spec to the DMA controller driver provided filter function.
457 * Pointer to the channel if found or %NULL otherwise.
459 struct dma_chan *acpi_dma_simple_xlate(struct acpi_dma_spec *dma_spec,
460 struct acpi_dma *adma)
462 struct acpi_dma_filter_info *info = adma->data;
464 if (!info || !info->filter_fn)
467 return dma_request_channel(info->dma_cap, info->filter_fn, dma_spec);
469 EXPORT_SYMBOL_GPL(acpi_dma_simple_xlate);