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