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1/*
2 * Device tree helpers for DMA request / controller
3 *
4 * Based on of_gpio.c
5 *
6 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/device.h>
14#include <linux/err.h>
15#include <linux/module.h>
16#include <linux/mutex.h>
17#include <linux/slab.h>
18#include <linux/of.h>
19#include <linux/of_dma.h>
20
21static LIST_HEAD(of_dma_list);
22static DEFINE_MUTEX(of_dma_lock);
23
24/**
25 * of_dma_find_controller - Get a DMA controller in DT DMA helpers list
26 * @dma_spec: pointer to DMA specifier as found in the device tree
27 *
28 * Finds a DMA controller with matching device node and number for dma cells
29 * in a list of registered DMA controllers. If a match is found a valid pointer
30 * to the DMA data stored is retuned. A NULL pointer is returned if no match is
31 * found.
32 */
33static struct of_dma *of_dma_find_controller(struct of_phandle_args *dma_spec)
34{
35 struct of_dma *ofdma;
36
37 list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers)
38 if (ofdma->of_node == dma_spec->np)
39 return ofdma;
40
41 pr_debug("%s: can't find DMA controller %s\n", __func__,
42 dma_spec->np->full_name);
43
44 return NULL;
45}
46
47/**
48 * of_dma_router_xlate - translation function for router devices
49 * @dma_spec: pointer to DMA specifier as found in the device tree
50 * @of_dma: pointer to DMA controller data (router information)
51 *
52 * The function creates new dma_spec to be passed to the router driver's
53 * of_dma_route_allocate() function to prepare a dma_spec which will be used
54 * to request channel from the real DMA controller.
55 */
56static struct dma_chan *of_dma_router_xlate(struct of_phandle_args *dma_spec,
57 struct of_dma *ofdma)
58{
59 struct dma_chan *chan;
60 struct of_dma *ofdma_target;
61 struct of_phandle_args dma_spec_target;
62 void *route_data;
63
64 /* translate the request for the real DMA controller */
65 memcpy(&dma_spec_target, dma_spec, sizeof(dma_spec_target));
66 route_data = ofdma->of_dma_route_allocate(&dma_spec_target, ofdma);
67 if (IS_ERR(route_data))
68 return NULL;
69
70 ofdma_target = of_dma_find_controller(&dma_spec_target);
71 if (!ofdma_target)
72 return NULL;
73
74 chan = ofdma_target->of_dma_xlate(&dma_spec_target, ofdma_target);
75 if (chan) {
76 chan->router = ofdma->dma_router;
77 chan->route_data = route_data;
78 } else {
79 ofdma->dma_router->route_free(ofdma->dma_router->dev,
80 route_data);
81 }
82
83 /*
84 * Need to put the node back since the ofdma->of_dma_route_allocate
85 * has taken it for generating the new, translated dma_spec
86 */
87 of_node_put(dma_spec_target.np);
88 return chan;
89}
90
91/**
92 * of_dma_controller_register - Register a DMA controller to DT DMA helpers
93 * @np: device node of DMA controller
94 * @of_dma_xlate: translation function which converts a phandle
95 * arguments list into a dma_chan structure
96 * @data pointer to controller specific data to be used by
97 * translation function
98 *
99 * Returns 0 on success or appropriate errno value on error.
100 *
101 * Allocated memory should be freed with appropriate of_dma_controller_free()
102 * call.
103 */
104int of_dma_controller_register(struct device_node *np,
105 struct dma_chan *(*of_dma_xlate)
106 (struct of_phandle_args *, struct of_dma *),
107 void *data)
108{
109 struct of_dma *ofdma;
110
111 if (!np || !of_dma_xlate) {
112 pr_err("%s: not enough information provided\n", __func__);
113 return -EINVAL;
114 }
115
116 ofdma = kzalloc(sizeof(*ofdma), GFP_KERNEL);
117 if (!ofdma)
118 return -ENOMEM;
119
120 ofdma->of_node = np;
121 ofdma->of_dma_xlate = of_dma_xlate;
122 ofdma->of_dma_data = data;
123
124 /* Now queue of_dma controller structure in list */
125 mutex_lock(&of_dma_lock);
126 list_add_tail(&ofdma->of_dma_controllers, &of_dma_list);
127 mutex_unlock(&of_dma_lock);
128
129 return 0;
130}
131EXPORT_SYMBOL_GPL(of_dma_controller_register);
132
133/**
134 * of_dma_controller_free - Remove a DMA controller from DT DMA helpers list
135 * @np: device node of DMA controller
136 *
137 * Memory allocated by of_dma_controller_register() is freed here.
138 */
139void of_dma_controller_free(struct device_node *np)
140{
141 struct of_dma *ofdma;
142
143 mutex_lock(&of_dma_lock);
144
145 list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers)
146 if (ofdma->of_node == np) {
147 list_del(&ofdma->of_dma_controllers);
148 kfree(ofdma);
149 break;
150 }
151
152 mutex_unlock(&of_dma_lock);
153}
154EXPORT_SYMBOL_GPL(of_dma_controller_free);
155
156/**
157 * of_dma_router_register - Register a DMA router to DT DMA helpers as a
158 * controller
159 * @np: device node of DMA router
160 * @of_dma_route_allocate: setup function for the router which need to
161 * modify the dma_spec for the DMA controller to
162 * use and to set up the requested route.
163 * @dma_router: pointer to dma_router structure to be used when
164 * the route need to be free up.
165 *
166 * Returns 0 on success or appropriate errno value on error.
167 *
168 * Allocated memory should be freed with appropriate of_dma_controller_free()
169 * call.
170 */
171int of_dma_router_register(struct device_node *np,
172 void *(*of_dma_route_allocate)
173 (struct of_phandle_args *, struct of_dma *),
174 struct dma_router *dma_router)
175{
176 struct of_dma *ofdma;
177
178 if (!np || !of_dma_route_allocate || !dma_router) {
179 pr_err("%s: not enough information provided\n", __func__);
180 return -EINVAL;
181 }
182
183 ofdma = kzalloc(sizeof(*ofdma), GFP_KERNEL);
184 if (!ofdma)
185 return -ENOMEM;
186
187 ofdma->of_node = np;
188 ofdma->of_dma_xlate = of_dma_router_xlate;
189 ofdma->of_dma_route_allocate = of_dma_route_allocate;
190 ofdma->dma_router = dma_router;
191
192 /* Now queue of_dma controller structure in list */
193 mutex_lock(&of_dma_lock);
194 list_add_tail(&ofdma->of_dma_controllers, &of_dma_list);
195 mutex_unlock(&of_dma_lock);
196
197 return 0;
198}
199EXPORT_SYMBOL_GPL(of_dma_router_register);
200
201/**
202 * of_dma_match_channel - Check if a DMA specifier matches name
203 * @np: device node to look for DMA channels
204 * @name: channel name to be matched
205 * @index: index of DMA specifier in list of DMA specifiers
206 * @dma_spec: pointer to DMA specifier as found in the device tree
207 *
208 * Check if the DMA specifier pointed to by the index in a list of DMA
209 * specifiers, matches the name provided. Returns 0 if the name matches and
210 * a valid pointer to the DMA specifier is found. Otherwise returns -ENODEV.
211 */
212static int of_dma_match_channel(struct device_node *np, const char *name,
213 int index, struct of_phandle_args *dma_spec)
214{
215 const char *s;
216
217 if (of_property_read_string_index(np, "dma-names", index, &s))
218 return -ENODEV;
219
220 if (strcmp(name, s))
221 return -ENODEV;
222
223 if (of_parse_phandle_with_args(np, "dmas", "#dma-cells", index,
224 dma_spec))
225 return -ENODEV;
226
227 return 0;
228}
229
230/**
231 * of_dma_request_slave_channel - Get the DMA slave channel
232 * @np: device node to get DMA request from
233 * @name: name of desired channel
234 *
235 * Returns pointer to appropriate DMA channel on success or an error pointer.
236 */
237struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
238 const char *name)
239{
240 struct of_phandle_args dma_spec;
241 struct of_dma *ofdma;
242 struct dma_chan *chan;
243 int count, i;
244 int ret_no_channel = -ENODEV;
245
246 if (!np || !name) {
247 pr_err("%s: not enough information provided\n", __func__);
248 return ERR_PTR(-ENODEV);
249 }
250
251 /* Silently fail if there is not even the "dmas" property */
252 if (!of_find_property(np, "dmas", NULL))
253 return ERR_PTR(-ENODEV);
254
255 count = of_property_count_strings(np, "dma-names");
256 if (count < 0) {
257 pr_err("%s: dma-names property of node '%s' missing or empty\n",
258 __func__, np->full_name);
259 return ERR_PTR(-ENODEV);
260 }
261
262 for (i = 0; i < count; i++) {
263 if (of_dma_match_channel(np, name, i, &dma_spec))
264 continue;
265
266 mutex_lock(&of_dma_lock);
267 ofdma = of_dma_find_controller(&dma_spec);
268
269 if (ofdma) {
270 chan = ofdma->of_dma_xlate(&dma_spec, ofdma);
271 } else {
272 ret_no_channel = -EPROBE_DEFER;
273 chan = NULL;
274 }
275
276 mutex_unlock(&of_dma_lock);
277
278 of_node_put(dma_spec.np);
279
280 if (chan)
281 return chan;
282 }
283
284 return ERR_PTR(ret_no_channel);
285}
286EXPORT_SYMBOL_GPL(of_dma_request_slave_channel);
287
288/**
289 * of_dma_simple_xlate - Simple DMA engine translation function
290 * @dma_spec: pointer to DMA specifier as found in the device tree
291 * @of_dma: pointer to DMA controller data
292 *
293 * A simple translation function for devices that use a 32-bit value for the
294 * filter_param when calling the DMA engine dma_request_channel() function.
295 * Note that this translation function requires that #dma-cells is equal to 1
296 * and the argument of the dma specifier is the 32-bit filter_param. Returns
297 * pointer to appropriate dma channel on success or NULL on error.
298 */
299struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
300 struct of_dma *ofdma)
301{
302 int count = dma_spec->args_count;
303 struct of_dma_filter_info *info = ofdma->of_dma_data;
304
305 if (!info || !info->filter_fn)
306 return NULL;
307
308 if (count != 1)
309 return NULL;
310
311 return dma_request_channel(info->dma_cap, info->filter_fn,
312 &dma_spec->args[0]);
313}
314EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
315
316/**
317 * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
318 * @dma_spec: pointer to DMA specifier as found in the device tree
319 * @of_dma: pointer to DMA controller data
320 *
321 * This function can be used as the of xlate callback for DMA driver which wants
322 * to match the channel based on the channel id. When using this xlate function
323 * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
324 * The data parameter of of_dma_controller_register must be a pointer to the
325 * dma_device struct the function should match upon.
326 *
327 * Returns pointer to appropriate dma channel on success or NULL on error.
328 */
329struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
330 struct of_dma *ofdma)
331{
332 struct dma_device *dev = ofdma->of_dma_data;
333 struct dma_chan *chan, *candidate = NULL;
334
335 if (!dev || dma_spec->args_count != 1)
336 return NULL;
337
338 list_for_each_entry(chan, &dev->channels, device_node)
339 if (chan->chan_id == dma_spec->args[0]) {
340 candidate = chan;
341 break;
342 }
343
344 if (!candidate)
345 return NULL;
346
347 return dma_get_slave_channel(candidate);
348}
349EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Device tree helpers for DMA request / controller
4 *
5 * Based on of_gpio.c
6 *
7 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
8 */
9
10#include <linux/device.h>
11#include <linux/err.h>
12#include <linux/module.h>
13#include <linux/mutex.h>
14#include <linux/slab.h>
15#include <linux/of.h>
16#include <linux/of_dma.h>
17
18#include "dmaengine.h"
19
20static LIST_HEAD(of_dma_list);
21static DEFINE_MUTEX(of_dma_lock);
22
23/**
24 * of_dma_find_controller - Get a DMA controller in DT DMA helpers list
25 * @dma_spec: pointer to DMA specifier as found in the device tree
26 *
27 * Finds a DMA controller with matching device node and number for dma cells
28 * in a list of registered DMA controllers. If a match is found a valid pointer
29 * to the DMA data stored is retuned. A NULL pointer is returned if no match is
30 * found.
31 */
32static struct of_dma *of_dma_find_controller(struct of_phandle_args *dma_spec)
33{
34 struct of_dma *ofdma;
35
36 list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers)
37 if (ofdma->of_node == dma_spec->np)
38 return ofdma;
39
40 pr_debug("%s: can't find DMA controller %pOF\n", __func__,
41 dma_spec->np);
42
43 return NULL;
44}
45
46/**
47 * of_dma_router_xlate - translation function for router devices
48 * @dma_spec: pointer to DMA specifier as found in the device tree
49 * @ofdma: pointer to DMA controller data (router information)
50 *
51 * The function creates new dma_spec to be passed to the router driver's
52 * of_dma_route_allocate() function to prepare a dma_spec which will be used
53 * to request channel from the real DMA controller.
54 */
55static struct dma_chan *of_dma_router_xlate(struct of_phandle_args *dma_spec,
56 struct of_dma *ofdma)
57{
58 struct dma_chan *chan;
59 struct of_dma *ofdma_target;
60 struct of_phandle_args dma_spec_target;
61 void *route_data;
62
63 /* translate the request for the real DMA controller */
64 memcpy(&dma_spec_target, dma_spec, sizeof(dma_spec_target));
65 route_data = ofdma->of_dma_route_allocate(&dma_spec_target, ofdma);
66 if (IS_ERR(route_data))
67 return NULL;
68
69 ofdma_target = of_dma_find_controller(&dma_spec_target);
70 if (!ofdma_target) {
71 ofdma->dma_router->route_free(ofdma->dma_router->dev,
72 route_data);
73 chan = ERR_PTR(-EPROBE_DEFER);
74 goto err;
75 }
76
77 chan = ofdma_target->of_dma_xlate(&dma_spec_target, ofdma_target);
78 if (IS_ERR_OR_NULL(chan)) {
79 ofdma->dma_router->route_free(ofdma->dma_router->dev,
80 route_data);
81 } else {
82 int ret = 0;
83
84 chan->router = ofdma->dma_router;
85 chan->route_data = route_data;
86
87 if (chan->device->device_router_config)
88 ret = chan->device->device_router_config(chan);
89
90 if (ret) {
91 dma_release_channel(chan);
92 chan = ERR_PTR(ret);
93 }
94 }
95
96err:
97 /*
98 * Need to put the node back since the ofdma->of_dma_route_allocate
99 * has taken it for generating the new, translated dma_spec
100 */
101 of_node_put(dma_spec_target.np);
102 return chan;
103}
104
105/**
106 * of_dma_controller_register - Register a DMA controller to DT DMA helpers
107 * @np: device node of DMA controller
108 * @of_dma_xlate: translation function which converts a phandle
109 * arguments list into a dma_chan structure
110 * @data: pointer to controller specific data to be used by
111 * translation function
112 *
113 * Returns 0 on success or appropriate errno value on error.
114 *
115 * Allocated memory should be freed with appropriate of_dma_controller_free()
116 * call.
117 */
118int of_dma_controller_register(struct device_node *np,
119 struct dma_chan *(*of_dma_xlate)
120 (struct of_phandle_args *, struct of_dma *),
121 void *data)
122{
123 struct of_dma *ofdma;
124
125 if (!np || !of_dma_xlate) {
126 pr_err("%s: not enough information provided\n", __func__);
127 return -EINVAL;
128 }
129
130 ofdma = kzalloc(sizeof(*ofdma), GFP_KERNEL);
131 if (!ofdma)
132 return -ENOMEM;
133
134 ofdma->of_node = np;
135 ofdma->of_dma_xlate = of_dma_xlate;
136 ofdma->of_dma_data = data;
137
138 /* Now queue of_dma controller structure in list */
139 mutex_lock(&of_dma_lock);
140 list_add_tail(&ofdma->of_dma_controllers, &of_dma_list);
141 mutex_unlock(&of_dma_lock);
142
143 return 0;
144}
145EXPORT_SYMBOL_GPL(of_dma_controller_register);
146
147/**
148 * of_dma_controller_free - Remove a DMA controller from DT DMA helpers list
149 * @np: device node of DMA controller
150 *
151 * Memory allocated by of_dma_controller_register() is freed here.
152 */
153void of_dma_controller_free(struct device_node *np)
154{
155 struct of_dma *ofdma;
156
157 mutex_lock(&of_dma_lock);
158
159 list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers)
160 if (ofdma->of_node == np) {
161 list_del(&ofdma->of_dma_controllers);
162 kfree(ofdma);
163 break;
164 }
165
166 mutex_unlock(&of_dma_lock);
167}
168EXPORT_SYMBOL_GPL(of_dma_controller_free);
169
170/**
171 * of_dma_router_register - Register a DMA router to DT DMA helpers as a
172 * controller
173 * @np: device node of DMA router
174 * @of_dma_route_allocate: setup function for the router which need to
175 * modify the dma_spec for the DMA controller to
176 * use and to set up the requested route.
177 * @dma_router: pointer to dma_router structure to be used when
178 * the route need to be free up.
179 *
180 * Returns 0 on success or appropriate errno value on error.
181 *
182 * Allocated memory should be freed with appropriate of_dma_controller_free()
183 * call.
184 */
185int of_dma_router_register(struct device_node *np,
186 void *(*of_dma_route_allocate)
187 (struct of_phandle_args *, struct of_dma *),
188 struct dma_router *dma_router)
189{
190 struct of_dma *ofdma;
191
192 if (!np || !of_dma_route_allocate || !dma_router) {
193 pr_err("%s: not enough information provided\n", __func__);
194 return -EINVAL;
195 }
196
197 ofdma = kzalloc(sizeof(*ofdma), GFP_KERNEL);
198 if (!ofdma)
199 return -ENOMEM;
200
201 ofdma->of_node = np;
202 ofdma->of_dma_xlate = of_dma_router_xlate;
203 ofdma->of_dma_route_allocate = of_dma_route_allocate;
204 ofdma->dma_router = dma_router;
205
206 /* Now queue of_dma controller structure in list */
207 mutex_lock(&of_dma_lock);
208 list_add_tail(&ofdma->of_dma_controllers, &of_dma_list);
209 mutex_unlock(&of_dma_lock);
210
211 return 0;
212}
213EXPORT_SYMBOL_GPL(of_dma_router_register);
214
215/**
216 * of_dma_match_channel - Check if a DMA specifier matches name
217 * @np: device node to look for DMA channels
218 * @name: channel name to be matched
219 * @index: index of DMA specifier in list of DMA specifiers
220 * @dma_spec: pointer to DMA specifier as found in the device tree
221 *
222 * Check if the DMA specifier pointed to by the index in a list of DMA
223 * specifiers, matches the name provided. Returns 0 if the name matches and
224 * a valid pointer to the DMA specifier is found. Otherwise returns -ENODEV.
225 */
226static int of_dma_match_channel(struct device_node *np, const char *name,
227 int index, struct of_phandle_args *dma_spec)
228{
229 const char *s;
230
231 if (of_property_read_string_index(np, "dma-names", index, &s))
232 return -ENODEV;
233
234 if (strcmp(name, s))
235 return -ENODEV;
236
237 if (of_parse_phandle_with_args(np, "dmas", "#dma-cells", index,
238 dma_spec))
239 return -ENODEV;
240
241 return 0;
242}
243
244/**
245 * of_dma_request_slave_channel - Get the DMA slave channel
246 * @np: device node to get DMA request from
247 * @name: name of desired channel
248 *
249 * Returns pointer to appropriate DMA channel on success or an error pointer.
250 */
251struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
252 const char *name)
253{
254 struct of_phandle_args dma_spec;
255 struct of_dma *ofdma;
256 struct dma_chan *chan;
257 int count, i, start;
258 int ret_no_channel = -ENODEV;
259 static atomic_t last_index;
260
261 if (!np || !name) {
262 pr_err("%s: not enough information provided\n", __func__);
263 return ERR_PTR(-ENODEV);
264 }
265
266 /* Silently fail if there is not even the "dmas" property */
267 if (!of_find_property(np, "dmas", NULL))
268 return ERR_PTR(-ENODEV);
269
270 count = of_property_count_strings(np, "dma-names");
271 if (count < 0) {
272 pr_err("%s: dma-names property of node '%pOF' missing or empty\n",
273 __func__, np);
274 return ERR_PTR(-ENODEV);
275 }
276
277 /*
278 * approximate an average distribution across multiple
279 * entries with the same name
280 */
281 start = atomic_inc_return(&last_index);
282 for (i = 0; i < count; i++) {
283 if (of_dma_match_channel(np, name,
284 (i + start) % count,
285 &dma_spec))
286 continue;
287
288 mutex_lock(&of_dma_lock);
289 ofdma = of_dma_find_controller(&dma_spec);
290
291 if (ofdma) {
292 chan = ofdma->of_dma_xlate(&dma_spec, ofdma);
293 } else {
294 ret_no_channel = -EPROBE_DEFER;
295 chan = NULL;
296 }
297
298 mutex_unlock(&of_dma_lock);
299
300 of_node_put(dma_spec.np);
301
302 if (chan)
303 return chan;
304 }
305
306 return ERR_PTR(ret_no_channel);
307}
308EXPORT_SYMBOL_GPL(of_dma_request_slave_channel);
309
310/**
311 * of_dma_simple_xlate - Simple DMA engine translation function
312 * @dma_spec: pointer to DMA specifier as found in the device tree
313 * @ofdma: pointer to DMA controller data
314 *
315 * A simple translation function for devices that use a 32-bit value for the
316 * filter_param when calling the DMA engine dma_request_channel() function.
317 * Note that this translation function requires that #dma-cells is equal to 1
318 * and the argument of the dma specifier is the 32-bit filter_param. Returns
319 * pointer to appropriate dma channel on success or NULL on error.
320 */
321struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
322 struct of_dma *ofdma)
323{
324 int count = dma_spec->args_count;
325 struct of_dma_filter_info *info = ofdma->of_dma_data;
326
327 if (!info || !info->filter_fn)
328 return NULL;
329
330 if (count != 1)
331 return NULL;
332
333 return __dma_request_channel(&info->dma_cap, info->filter_fn,
334 &dma_spec->args[0], dma_spec->np);
335}
336EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
337
338/**
339 * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
340 * @dma_spec: pointer to DMA specifier as found in the device tree
341 * @ofdma: pointer to DMA controller data
342 *
343 * This function can be used as the of xlate callback for DMA driver which wants
344 * to match the channel based on the channel id. When using this xlate function
345 * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
346 * The data parameter of of_dma_controller_register must be a pointer to the
347 * dma_device struct the function should match upon.
348 *
349 * Returns pointer to appropriate dma channel on success or NULL on error.
350 */
351struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
352 struct of_dma *ofdma)
353{
354 struct dma_device *dev = ofdma->of_dma_data;
355 struct dma_chan *chan, *candidate = NULL;
356
357 if (!dev || dma_spec->args_count != 1)
358 return NULL;
359
360 list_for_each_entry(chan, &dev->channels, device_node)
361 if (chan->chan_id == dma_spec->args[0]) {
362 candidate = chan;
363 break;
364 }
365
366 if (!candidate)
367 return NULL;
368
369 return dma_get_slave_channel(candidate);
370}
371EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);