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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 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 break;
139 }
140
141 grp = (struct acpi_csrt_group *)((void *)grp + grp->length);
142 }
143
144 acpi_put_table((struct acpi_table_header *)csrt);
145}
146
147/**
148 * acpi_dma_controller_register - Register a DMA controller to ACPI DMA helpers
149 * @dev: struct device of DMA controller
150 * @acpi_dma_xlate: translation function which converts a dma specifier
151 * into a dma_chan structure
152 * @data: pointer to controller specific data to be used by
153 * translation function
154 *
155 * Allocated memory should be freed with appropriate acpi_dma_controller_free()
156 * call.
157 *
158 * Return:
159 * 0 on success or appropriate errno value on error.
160 */
161int acpi_dma_controller_register(struct device *dev,
162 struct dma_chan *(*acpi_dma_xlate)
163 (struct acpi_dma_spec *, struct acpi_dma *),
164 void *data)
165{
166 struct acpi_device *adev;
167 struct acpi_dma *adma;
168
169 if (!dev || !acpi_dma_xlate)
170 return -EINVAL;
171
172 /* Check if the device was enumerated by ACPI */
173 adev = ACPI_COMPANION(dev);
174 if (!adev)
175 return -EINVAL;
176
177 adma = kzalloc(sizeof(*adma), GFP_KERNEL);
178 if (!adma)
179 return -ENOMEM;
180
181 adma->dev = dev;
182 adma->acpi_dma_xlate = acpi_dma_xlate;
183 adma->data = data;
184
185 acpi_dma_parse_csrt(adev, adma);
186
187 /* Now queue acpi_dma controller structure in list */
188 mutex_lock(&acpi_dma_lock);
189 list_add_tail(&adma->dma_controllers, &acpi_dma_list);
190 mutex_unlock(&acpi_dma_lock);
191
192 return 0;
193}
194EXPORT_SYMBOL_GPL(acpi_dma_controller_register);
195
196/**
197 * acpi_dma_controller_free - Remove a DMA controller from ACPI DMA helpers list
198 * @dev: struct device of DMA controller
199 *
200 * Memory allocated by acpi_dma_controller_register() is freed here.
201 *
202 * Return:
203 * 0 on success or appropriate errno value on error.
204 */
205int acpi_dma_controller_free(struct device *dev)
206{
207 struct acpi_dma *adma;
208
209 if (!dev)
210 return -EINVAL;
211
212 mutex_lock(&acpi_dma_lock);
213
214 list_for_each_entry(adma, &acpi_dma_list, dma_controllers)
215 if (adma->dev == dev) {
216 list_del(&adma->dma_controllers);
217 mutex_unlock(&acpi_dma_lock);
218 kfree(adma);
219 return 0;
220 }
221
222 mutex_unlock(&acpi_dma_lock);
223 return -ENODEV;
224}
225EXPORT_SYMBOL_GPL(acpi_dma_controller_free);
226
227static void devm_acpi_dma_release(struct device *dev, void *res)
228{
229 acpi_dma_controller_free(dev);
230}
231
232/**
233 * devm_acpi_dma_controller_register - resource managed acpi_dma_controller_register()
234 * @dev: device that is registering this DMA controller
235 * @acpi_dma_xlate: translation function
236 * @data: pointer to controller specific data
237 *
238 * Managed acpi_dma_controller_register(). DMA controller registered by this
239 * function are automatically freed on driver detach. See
240 * acpi_dma_controller_register() for more information.
241 *
242 * Return:
243 * 0 on success or appropriate errno value on error.
244 */
245int devm_acpi_dma_controller_register(struct device *dev,
246 struct dma_chan *(*acpi_dma_xlate)
247 (struct acpi_dma_spec *, struct acpi_dma *),
248 void *data)
249{
250 void *res;
251 int ret;
252
253 res = devres_alloc(devm_acpi_dma_release, 0, GFP_KERNEL);
254 if (!res)
255 return -ENOMEM;
256
257 ret = acpi_dma_controller_register(dev, acpi_dma_xlate, data);
258 if (ret) {
259 devres_free(res);
260 return ret;
261 }
262 devres_add(dev, res);
263 return 0;
264}
265EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_register);
266
267/**
268 * devm_acpi_dma_controller_free - resource managed acpi_dma_controller_free()
269 * @dev: device that is unregistering as DMA controller
270 *
271 * Unregister a DMA controller registered with
272 * devm_acpi_dma_controller_register(). Normally this function will not need to
273 * be called and the resource management code will ensure that the resource is
274 * freed.
275 */
276void devm_acpi_dma_controller_free(struct device *dev)
277{
278 WARN_ON(devres_release(dev, devm_acpi_dma_release, NULL, NULL));
279}
280EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free);
281
282/**
283 * acpi_dma_update_dma_spec - prepare dma specifier to pass to translation function
284 * @adma: struct acpi_dma of DMA controller
285 * @dma_spec: dma specifier to update
286 *
287 * Accordingly to ACPI 5.0 Specification Table 6-170 "Fixed DMA Resource
288 * Descriptor":
289 * DMA Request Line bits is a platform-relative number uniquely
290 * identifying the request line assigned. Request line-to-Controller
291 * mapping is done in a controller-specific OS driver.
292 * That's why we can safely adjust slave_id when the appropriate controller is
293 * found.
294 *
295 * Return:
296 * 0, if no information is avaiable, -1 on mismatch, and 1 otherwise.
297 */
298static int acpi_dma_update_dma_spec(struct acpi_dma *adma,
299 struct acpi_dma_spec *dma_spec)
300{
301 /* Set link to the DMA controller device */
302 dma_spec->dev = adma->dev;
303
304 /* Check if the request line range is available */
305 if (adma->base_request_line == 0 && adma->end_request_line == 0)
306 return 0;
307
308 /* Check if slave_id falls to the range */
309 if (dma_spec->slave_id < adma->base_request_line ||
310 dma_spec->slave_id > adma->end_request_line)
311 return -1;
312
313 /*
314 * Here we adjust slave_id. It should be a relative number to the base
315 * request line.
316 */
317 dma_spec->slave_id -= adma->base_request_line;
318
319 return 1;
320}
321
322struct acpi_dma_parser_data {
323 struct acpi_dma_spec dma_spec;
324 size_t index;
325 size_t n;
326};
327
328/**
329 * acpi_dma_parse_fixed_dma - Parse FixedDMA ACPI resources to a DMA specifier
330 * @res: struct acpi_resource to get FixedDMA resources from
331 * @data: pointer to a helper struct acpi_dma_parser_data
332 */
333static int acpi_dma_parse_fixed_dma(struct acpi_resource *res, void *data)
334{
335 struct acpi_dma_parser_data *pdata = data;
336
337 if (res->type == ACPI_RESOURCE_TYPE_FIXED_DMA) {
338 struct acpi_resource_fixed_dma *dma = &res->data.fixed_dma;
339
340 if (pdata->n++ == pdata->index) {
341 pdata->dma_spec.chan_id = dma->channels;
342 pdata->dma_spec.slave_id = dma->request_lines;
343 }
344 }
345
346 /* Tell the ACPI core to skip this resource */
347 return 1;
348}
349
350/**
351 * acpi_dma_request_slave_chan_by_index - Get the DMA slave channel
352 * @dev: struct device to get DMA request from
353 * @index: index of FixedDMA descriptor for @dev
354 *
355 * Return:
356 * Pointer to appropriate dma channel on success or an error pointer.
357 */
358struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
359 size_t index)
360{
361 struct acpi_dma_parser_data pdata;
362 struct acpi_dma_spec *dma_spec = &pdata.dma_spec;
363 struct acpi_device *adev = ACPI_COMPANION(dev);
364 struct list_head resource_list;
365 struct acpi_dma *adma;
366 struct dma_chan *chan = NULL;
367 int found;
368 int ret;
369
370 memset(&pdata, 0, sizeof(pdata));
371 pdata.index = index;
372
373 /* Initial values for the request line and channel */
374 dma_spec->chan_id = -1;
375 dma_spec->slave_id = -1;
376
377 INIT_LIST_HEAD(&resource_list);
378 ret = acpi_dev_get_resources(adev, &resource_list,
379 acpi_dma_parse_fixed_dma, &pdata);
380 acpi_dev_free_resource_list(&resource_list);
381 if (ret < 0)
382 return ERR_PTR(ret);
383
384 if (dma_spec->slave_id < 0 || dma_spec->chan_id < 0)
385 return ERR_PTR(-ENODEV);
386
387 mutex_lock(&acpi_dma_lock);
388
389 list_for_each_entry(adma, &acpi_dma_list, dma_controllers) {
390 /*
391 * We are not going to call translation function if slave_id
392 * doesn't fall to the request range.
393 */
394 found = acpi_dma_update_dma_spec(adma, dma_spec);
395 if (found < 0)
396 continue;
397 chan = adma->acpi_dma_xlate(dma_spec, adma);
398 /*
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.
402 */
403 if (found > 0 || chan)
404 break;
405 }
406
407 mutex_unlock(&acpi_dma_lock);
408 return chan ? chan : ERR_PTR(-EPROBE_DEFER);
409}
410EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index);
411
412/**
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
416 *
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.
420 *
421 * If the device has "dma-names" property the FixedDMA descriptor indices
422 * are retrieved based on those. Otherwise the function falls back using
423 * hardcoded indices.
424 *
425 * Return:
426 * Pointer to appropriate dma channel on success or an error pointer.
427 */
428struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev,
429 const char *name)
430{
431 int index;
432
433 index = device_property_match_string(dev, "dma-names", name);
434 if (index < 0) {
435 if (!strcmp(name, "tx"))
436 index = 0;
437 else if (!strcmp(name, "rx"))
438 index = 1;
439 else
440 return ERR_PTR(-ENODEV);
441 }
442
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);
445}
446EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_name);
447
448/**
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
452 *
453 * A simple translation function for ACPI based devices. Passes &struct
454 * dma_spec to the DMA controller driver provided filter function.
455 *
456 * Return:
457 * Pointer to the channel if found or %NULL otherwise.
458 */
459struct dma_chan *acpi_dma_simple_xlate(struct acpi_dma_spec *dma_spec,
460 struct acpi_dma *adma)
461{
462 struct acpi_dma_filter_info *info = adma->data;
463
464 if (!info || !info->filter_fn)
465 return NULL;
466
467 return dma_request_channel(info->dma_cap, info->filter_fn, dma_spec);
468}
469EXPORT_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);