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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
aa3da644 JH |
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/ | |
aa3da644 JH |
8 | */ |
9 | ||
10 | #include <linux/device.h> | |
11 | #include <linux/err.h> | |
12 | #include <linux/module.h> | |
de61608a | 13 | #include <linux/mutex.h> |
aa3da644 JH |
14 | #include <linux/slab.h> |
15 | #include <linux/of.h> | |
16 | #include <linux/of_dma.h> | |
17 | ||
c3c431de GU |
18 | #include "dmaengine.h" |
19 | ||
aa3da644 | 20 | static LIST_HEAD(of_dma_list); |
de61608a | 21 | static DEFINE_MUTEX(of_dma_lock); |
aa3da644 JH |
22 | |
23 | /** | |
de61608a | 24 | * of_dma_find_controller - Get a DMA controller in DT DMA helpers list |
9743a3b6 JH |
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 | |
de61608a LPC |
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. | |
aa3da644 | 31 | */ |
de61608a | 32 | static struct of_dma *of_dma_find_controller(struct of_phandle_args *dma_spec) |
aa3da644 JH |
33 | { |
34 | struct of_dma *ofdma; | |
35 | ||
9743a3b6 | 36 | list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers) |
8552bb4f | 37 | if (ofdma->of_node == dma_spec->np) |
aa3da644 | 38 | return ofdma; |
9743a3b6 | 39 | |
c6c93048 RH |
40 | pr_debug("%s: can't find DMA controller %pOF\n", __func__, |
41 | dma_spec->np); | |
aa3da644 JH |
42 | |
43 | return NULL; | |
44 | } | |
45 | ||
56f13c0d PU |
46 | /** |
47 | * of_dma_router_xlate - translation function for router devices | |
48 | * @dma_spec: pointer to DMA specifier as found in the device tree | |
7d8c9148 | 49 | * @ofdma: pointer to DMA controller data (router information) |
56f13c0d PU |
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 | */ | |
55 | static 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 | return NULL; | |
72 | ||
73 | chan = ofdma_target->of_dma_xlate(&dma_spec_target, ofdma_target); | |
5b2aa9f9 | 74 | if (IS_ERR_OR_NULL(chan)) { |
56f13c0d PU |
75 | ofdma->dma_router->route_free(ofdma->dma_router->dev, |
76 | route_data); | |
5b2aa9f9 | 77 | } else { |
4f910c03 PU |
78 | int ret = 0; |
79 | ||
5b2aa9f9 PU |
80 | chan->router = ofdma->dma_router; |
81 | chan->route_data = route_data; | |
4f910c03 PU |
82 | |
83 | if (chan->device->device_router_config) | |
84 | ret = chan->device->device_router_config(chan); | |
85 | ||
86 | if (ret) { | |
87 | dma_release_channel(chan); | |
88 | chan = ERR_PTR(ret); | |
89 | } | |
56f13c0d PU |
90 | } |
91 | ||
92 | /* | |
93 | * Need to put the node back since the ofdma->of_dma_route_allocate | |
94 | * has taken it for generating the new, translated dma_spec | |
95 | */ | |
96 | of_node_put(dma_spec_target.np); | |
97 | return chan; | |
98 | } | |
99 | ||
aa3da644 JH |
100 | /** |
101 | * of_dma_controller_register - Register a DMA controller to DT DMA helpers | |
102 | * @np: device node of DMA controller | |
103 | * @of_dma_xlate: translation function which converts a phandle | |
104 | * arguments list into a dma_chan structure | |
7d8c9148 | 105 | * @data: pointer to controller specific data to be used by |
aa3da644 JH |
106 | * translation function |
107 | * | |
108 | * Returns 0 on success or appropriate errno value on error. | |
109 | * | |
110 | * Allocated memory should be freed with appropriate of_dma_controller_free() | |
111 | * call. | |
112 | */ | |
113 | int of_dma_controller_register(struct device_node *np, | |
114 | struct dma_chan *(*of_dma_xlate) | |
115 | (struct of_phandle_args *, struct of_dma *), | |
116 | void *data) | |
117 | { | |
118 | struct of_dma *ofdma; | |
aa3da644 JH |
119 | |
120 | if (!np || !of_dma_xlate) { | |
121 | pr_err("%s: not enough information provided\n", __func__); | |
122 | return -EINVAL; | |
123 | } | |
124 | ||
125 | ofdma = kzalloc(sizeof(*ofdma), GFP_KERNEL); | |
126 | if (!ofdma) | |
127 | return -ENOMEM; | |
128 | ||
aa3da644 | 129 | ofdma->of_node = np; |
aa3da644 JH |
130 | ofdma->of_dma_xlate = of_dma_xlate; |
131 | ofdma->of_dma_data = data; | |
132 | ||
133 | /* Now queue of_dma controller structure in list */ | |
de61608a | 134 | mutex_lock(&of_dma_lock); |
9743a3b6 | 135 | list_add_tail(&ofdma->of_dma_controllers, &of_dma_list); |
de61608a | 136 | mutex_unlock(&of_dma_lock); |
aa3da644 JH |
137 | |
138 | return 0; | |
139 | } | |
140 | EXPORT_SYMBOL_GPL(of_dma_controller_register); | |
141 | ||
142 | /** | |
143 | * of_dma_controller_free - Remove a DMA controller from DT DMA helpers list | |
144 | * @np: device node of DMA controller | |
145 | * | |
146 | * Memory allocated by of_dma_controller_register() is freed here. | |
147 | */ | |
de61608a | 148 | void of_dma_controller_free(struct device_node *np) |
aa3da644 JH |
149 | { |
150 | struct of_dma *ofdma; | |
151 | ||
de61608a | 152 | mutex_lock(&of_dma_lock); |
9743a3b6 JH |
153 | |
154 | list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers) | |
155 | if (ofdma->of_node == np) { | |
9743a3b6 | 156 | list_del(&ofdma->of_dma_controllers); |
9743a3b6 | 157 | kfree(ofdma); |
de61608a | 158 | break; |
9743a3b6 JH |
159 | } |
160 | ||
de61608a | 161 | mutex_unlock(&of_dma_lock); |
aa3da644 JH |
162 | } |
163 | EXPORT_SYMBOL_GPL(of_dma_controller_free); | |
164 | ||
56f13c0d PU |
165 | /** |
166 | * of_dma_router_register - Register a DMA router to DT DMA helpers as a | |
167 | * controller | |
168 | * @np: device node of DMA router | |
169 | * @of_dma_route_allocate: setup function for the router which need to | |
170 | * modify the dma_spec for the DMA controller to | |
171 | * use and to set up the requested route. | |
172 | * @dma_router: pointer to dma_router structure to be used when | |
173 | * the route need to be free up. | |
174 | * | |
175 | * Returns 0 on success or appropriate errno value on error. | |
176 | * | |
177 | * Allocated memory should be freed with appropriate of_dma_controller_free() | |
178 | * call. | |
179 | */ | |
180 | int of_dma_router_register(struct device_node *np, | |
181 | void *(*of_dma_route_allocate) | |
182 | (struct of_phandle_args *, struct of_dma *), | |
183 | struct dma_router *dma_router) | |
184 | { | |
185 | struct of_dma *ofdma; | |
186 | ||
187 | if (!np || !of_dma_route_allocate || !dma_router) { | |
188 | pr_err("%s: not enough information provided\n", __func__); | |
189 | return -EINVAL; | |
190 | } | |
191 | ||
192 | ofdma = kzalloc(sizeof(*ofdma), GFP_KERNEL); | |
193 | if (!ofdma) | |
194 | return -ENOMEM; | |
195 | ||
196 | ofdma->of_node = np; | |
197 | ofdma->of_dma_xlate = of_dma_router_xlate; | |
198 | ofdma->of_dma_route_allocate = of_dma_route_allocate; | |
199 | ofdma->dma_router = dma_router; | |
200 | ||
201 | /* Now queue of_dma controller structure in list */ | |
202 | mutex_lock(&of_dma_lock); | |
203 | list_add_tail(&ofdma->of_dma_controllers, &of_dma_list); | |
204 | mutex_unlock(&of_dma_lock); | |
205 | ||
206 | return 0; | |
207 | } | |
208 | EXPORT_SYMBOL_GPL(of_dma_router_register); | |
209 | ||
aa3da644 | 210 | /** |
5ca7c109 | 211 | * of_dma_match_channel - Check if a DMA specifier matches name |
aa3da644 | 212 | * @np: device node to look for DMA channels |
5ca7c109 JH |
213 | * @name: channel name to be matched |
214 | * @index: index of DMA specifier in list of DMA specifiers | |
aa3da644 JH |
215 | * @dma_spec: pointer to DMA specifier as found in the device tree |
216 | * | |
5ca7c109 JH |
217 | * Check if the DMA specifier pointed to by the index in a list of DMA |
218 | * specifiers, matches the name provided. Returns 0 if the name matches and | |
219 | * a valid pointer to the DMA specifier is found. Otherwise returns -ENODEV. | |
aa3da644 | 220 | */ |
bef29ec5 MP |
221 | static int of_dma_match_channel(struct device_node *np, const char *name, |
222 | int index, struct of_phandle_args *dma_spec) | |
aa3da644 | 223 | { |
aa3da644 JH |
224 | const char *s; |
225 | ||
5ca7c109 JH |
226 | if (of_property_read_string_index(np, "dma-names", index, &s)) |
227 | return -ENODEV; | |
aa3da644 | 228 | |
5ca7c109 JH |
229 | if (strcmp(name, s)) |
230 | return -ENODEV; | |
aa3da644 | 231 | |
5ca7c109 JH |
232 | if (of_parse_phandle_with_args(np, "dmas", "#dma-cells", index, |
233 | dma_spec)) | |
234 | return -ENODEV; | |
aa3da644 | 235 | |
5ca7c109 | 236 | return 0; |
aa3da644 JH |
237 | } |
238 | ||
239 | /** | |
240 | * of_dma_request_slave_channel - Get the DMA slave channel | |
241 | * @np: device node to get DMA request from | |
242 | * @name: name of desired channel | |
243 | * | |
0ad7c000 | 244 | * Returns pointer to appropriate DMA channel on success or an error pointer. |
aa3da644 JH |
245 | */ |
246 | struct dma_chan *of_dma_request_slave_channel(struct device_node *np, | |
bef29ec5 | 247 | const char *name) |
aa3da644 JH |
248 | { |
249 | struct of_phandle_args dma_spec; | |
250 | struct of_dma *ofdma; | |
251 | struct dma_chan *chan; | |
20ea6be6 | 252 | int count, i, start; |
0ad7c000 | 253 | int ret_no_channel = -ENODEV; |
20ea6be6 | 254 | static atomic_t last_index; |
aa3da644 JH |
255 | |
256 | if (!np || !name) { | |
257 | pr_err("%s: not enough information provided\n", __func__); | |
0ad7c000 | 258 | return ERR_PTR(-ENODEV); |
aa3da644 JH |
259 | } |
260 | ||
c914570f WS |
261 | /* Silently fail if there is not even the "dmas" property */ |
262 | if (!of_find_property(np, "dmas", NULL)) | |
263 | return ERR_PTR(-ENODEV); | |
264 | ||
5ca7c109 JH |
265 | count = of_property_count_strings(np, "dma-names"); |
266 | if (count < 0) { | |
c6c93048 RH |
267 | pr_err("%s: dma-names property of node '%pOF' missing or empty\n", |
268 | __func__, np); | |
0ad7c000 | 269 | return ERR_PTR(-ENODEV); |
5ca7c109 JH |
270 | } |
271 | ||
20ea6be6 NS |
272 | /* |
273 | * approximate an average distribution across multiple | |
274 | * entries with the same name | |
275 | */ | |
276 | start = atomic_inc_return(&last_index); | |
5ca7c109 | 277 | for (i = 0; i < count; i++) { |
20ea6be6 NS |
278 | if (of_dma_match_channel(np, name, |
279 | (i + start) % count, | |
280 | &dma_spec)) | |
5ca7c109 | 281 | continue; |
aa3da644 | 282 | |
de61608a LPC |
283 | mutex_lock(&of_dma_lock); |
284 | ofdma = of_dma_find_controller(&dma_spec); | |
aa3da644 | 285 | |
0ad7c000 | 286 | if (ofdma) { |
f22eb140 | 287 | chan = ofdma->of_dma_xlate(&dma_spec, ofdma); |
0ad7c000 SW |
288 | } else { |
289 | ret_no_channel = -EPROBE_DEFER; | |
f22eb140 | 290 | chan = NULL; |
0ad7c000 | 291 | } |
de61608a LPC |
292 | |
293 | mutex_unlock(&of_dma_lock); | |
9743a3b6 | 294 | |
aa3da644 JH |
295 | of_node_put(dma_spec.np); |
296 | ||
5ca7c109 JH |
297 | if (chan) |
298 | return chan; | |
299 | } | |
aa3da644 | 300 | |
0ad7c000 | 301 | return ERR_PTR(ret_no_channel); |
aa3da644 | 302 | } |
0aed1124 | 303 | EXPORT_SYMBOL_GPL(of_dma_request_slave_channel); |
aa3da644 JH |
304 | |
305 | /** | |
306 | * of_dma_simple_xlate - Simple DMA engine translation function | |
307 | * @dma_spec: pointer to DMA specifier as found in the device tree | |
7d8c9148 | 308 | * @ofdma: pointer to DMA controller data |
aa3da644 JH |
309 | * |
310 | * A simple translation function for devices that use a 32-bit value for the | |
311 | * filter_param when calling the DMA engine dma_request_channel() function. | |
312 | * Note that this translation function requires that #dma-cells is equal to 1 | |
313 | * and the argument of the dma specifier is the 32-bit filter_param. Returns | |
314 | * pointer to appropriate dma channel on success or NULL on error. | |
315 | */ | |
316 | struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec, | |
317 | struct of_dma *ofdma) | |
318 | { | |
319 | int count = dma_spec->args_count; | |
320 | struct of_dma_filter_info *info = ofdma->of_dma_data; | |
321 | ||
322 | if (!info || !info->filter_fn) | |
323 | return NULL; | |
324 | ||
325 | if (count != 1) | |
326 | return NULL; | |
327 | ||
f5151311 BW |
328 | return __dma_request_channel(&info->dma_cap, info->filter_fn, |
329 | &dma_spec->args[0], dma_spec->np); | |
aa3da644 JH |
330 | } |
331 | EXPORT_SYMBOL_GPL(of_dma_simple_xlate); | |
16369efb AP |
332 | |
333 | /** | |
334 | * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id | |
335 | * @dma_spec: pointer to DMA specifier as found in the device tree | |
7d8c9148 | 336 | * @ofdma: pointer to DMA controller data |
16369efb AP |
337 | * |
338 | * This function can be used as the of xlate callback for DMA driver which wants | |
339 | * to match the channel based on the channel id. When using this xlate function | |
340 | * the #dma-cells propety of the DMA controller dt node needs to be set to 1. | |
341 | * The data parameter of of_dma_controller_register must be a pointer to the | |
342 | * dma_device struct the function should match upon. | |
343 | * | |
344 | * Returns pointer to appropriate dma channel on success or NULL on error. | |
345 | */ | |
346 | struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec, | |
347 | struct of_dma *ofdma) | |
348 | { | |
349 | struct dma_device *dev = ofdma->of_dma_data; | |
350 | struct dma_chan *chan, *candidate = NULL; | |
351 | ||
352 | if (!dev || dma_spec->args_count != 1) | |
353 | return NULL; | |
354 | ||
355 | list_for_each_entry(chan, &dev->channels, device_node) | |
356 | if (chan->chan_id == dma_spec->args[0]) { | |
357 | candidate = chan; | |
358 | break; | |
359 | } | |
360 | ||
361 | if (!candidate) | |
362 | return NULL; | |
363 | ||
364 | return dma_get_slave_channel(candidate); | |
365 | } | |
366 | EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id); |