]>
Commit | Line | Data |
---|---|---|
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 | ||
18 | static LIST_HEAD(of_dma_list); | |
de61608a | 19 | static DEFINE_MUTEX(of_dma_lock); |
aa3da644 JH |
20 | |
21 | /** | |
de61608a | 22 | * of_dma_find_controller - Get a DMA controller in DT DMA helpers list |
9743a3b6 JH |
23 | * @dma_spec: pointer to DMA specifier as found in the device tree |
24 | * | |
25 | * Finds a DMA controller with matching device node and number for dma cells | |
de61608a LPC |
26 | * in a list of registered DMA controllers. If a match is found a valid pointer |
27 | * to the DMA data stored is retuned. A NULL pointer is returned if no match is | |
28 | * found. | |
aa3da644 | 29 | */ |
de61608a | 30 | static struct of_dma *of_dma_find_controller(struct of_phandle_args *dma_spec) |
aa3da644 JH |
31 | { |
32 | struct of_dma *ofdma; | |
33 | ||
9743a3b6 | 34 | list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers) |
8552bb4f | 35 | if (ofdma->of_node == dma_spec->np) |
aa3da644 | 36 | return ofdma; |
9743a3b6 | 37 | |
c6c93048 RH |
38 | pr_debug("%s: can't find DMA controller %pOF\n", __func__, |
39 | dma_spec->np); | |
aa3da644 JH |
40 | |
41 | return NULL; | |
42 | } | |
43 | ||
56f13c0d PU |
44 | /** |
45 | * of_dma_router_xlate - translation function for router devices | |
46 | * @dma_spec: pointer to DMA specifier as found in the device tree | |
47 | * @of_dma: pointer to DMA controller data (router information) | |
48 | * | |
49 | * The function creates new dma_spec to be passed to the router driver's | |
50 | * of_dma_route_allocate() function to prepare a dma_spec which will be used | |
51 | * to request channel from the real DMA controller. | |
52 | */ | |
53 | static struct dma_chan *of_dma_router_xlate(struct of_phandle_args *dma_spec, | |
54 | struct of_dma *ofdma) | |
55 | { | |
56 | struct dma_chan *chan; | |
57 | struct of_dma *ofdma_target; | |
58 | struct of_phandle_args dma_spec_target; | |
59 | void *route_data; | |
60 | ||
61 | /* translate the request for the real DMA controller */ | |
62 | memcpy(&dma_spec_target, dma_spec, sizeof(dma_spec_target)); | |
63 | route_data = ofdma->of_dma_route_allocate(&dma_spec_target, ofdma); | |
64 | if (IS_ERR(route_data)) | |
65 | return NULL; | |
66 | ||
67 | ofdma_target = of_dma_find_controller(&dma_spec_target); | |
68 | if (!ofdma_target) | |
69 | return NULL; | |
70 | ||
71 | chan = ofdma_target->of_dma_xlate(&dma_spec_target, ofdma_target); | |
72 | if (chan) { | |
73 | chan->router = ofdma->dma_router; | |
74 | chan->route_data = route_data; | |
75 | } else { | |
76 | ofdma->dma_router->route_free(ofdma->dma_router->dev, | |
77 | route_data); | |
78 | } | |
79 | ||
80 | /* | |
81 | * Need to put the node back since the ofdma->of_dma_route_allocate | |
82 | * has taken it for generating the new, translated dma_spec | |
83 | */ | |
84 | of_node_put(dma_spec_target.np); | |
85 | return chan; | |
86 | } | |
87 | ||
aa3da644 JH |
88 | /** |
89 | * of_dma_controller_register - Register a DMA controller to DT DMA helpers | |
90 | * @np: device node of DMA controller | |
91 | * @of_dma_xlate: translation function which converts a phandle | |
92 | * arguments list into a dma_chan structure | |
93 | * @data pointer to controller specific data to be used by | |
94 | * translation function | |
95 | * | |
96 | * Returns 0 on success or appropriate errno value on error. | |
97 | * | |
98 | * Allocated memory should be freed with appropriate of_dma_controller_free() | |
99 | * call. | |
100 | */ | |
101 | int of_dma_controller_register(struct device_node *np, | |
102 | struct dma_chan *(*of_dma_xlate) | |
103 | (struct of_phandle_args *, struct of_dma *), | |
104 | void *data) | |
105 | { | |
106 | struct of_dma *ofdma; | |
aa3da644 JH |
107 | |
108 | if (!np || !of_dma_xlate) { | |
109 | pr_err("%s: not enough information provided\n", __func__); | |
110 | return -EINVAL; | |
111 | } | |
112 | ||
113 | ofdma = kzalloc(sizeof(*ofdma), GFP_KERNEL); | |
114 | if (!ofdma) | |
115 | return -ENOMEM; | |
116 | ||
aa3da644 | 117 | ofdma->of_node = np; |
aa3da644 JH |
118 | ofdma->of_dma_xlate = of_dma_xlate; |
119 | ofdma->of_dma_data = data; | |
120 | ||
121 | /* Now queue of_dma controller structure in list */ | |
de61608a | 122 | mutex_lock(&of_dma_lock); |
9743a3b6 | 123 | list_add_tail(&ofdma->of_dma_controllers, &of_dma_list); |
de61608a | 124 | mutex_unlock(&of_dma_lock); |
aa3da644 JH |
125 | |
126 | return 0; | |
127 | } | |
128 | EXPORT_SYMBOL_GPL(of_dma_controller_register); | |
129 | ||
130 | /** | |
131 | * of_dma_controller_free - Remove a DMA controller from DT DMA helpers list | |
132 | * @np: device node of DMA controller | |
133 | * | |
134 | * Memory allocated by of_dma_controller_register() is freed here. | |
135 | */ | |
de61608a | 136 | void of_dma_controller_free(struct device_node *np) |
aa3da644 JH |
137 | { |
138 | struct of_dma *ofdma; | |
139 | ||
de61608a | 140 | mutex_lock(&of_dma_lock); |
9743a3b6 JH |
141 | |
142 | list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers) | |
143 | if (ofdma->of_node == np) { | |
9743a3b6 | 144 | list_del(&ofdma->of_dma_controllers); |
9743a3b6 | 145 | kfree(ofdma); |
de61608a | 146 | break; |
9743a3b6 JH |
147 | } |
148 | ||
de61608a | 149 | mutex_unlock(&of_dma_lock); |
aa3da644 JH |
150 | } |
151 | EXPORT_SYMBOL_GPL(of_dma_controller_free); | |
152 | ||
56f13c0d PU |
153 | /** |
154 | * of_dma_router_register - Register a DMA router to DT DMA helpers as a | |
155 | * controller | |
156 | * @np: device node of DMA router | |
157 | * @of_dma_route_allocate: setup function for the router which need to | |
158 | * modify the dma_spec for the DMA controller to | |
159 | * use and to set up the requested route. | |
160 | * @dma_router: pointer to dma_router structure to be used when | |
161 | * the route need to be free up. | |
162 | * | |
163 | * Returns 0 on success or appropriate errno value on error. | |
164 | * | |
165 | * Allocated memory should be freed with appropriate of_dma_controller_free() | |
166 | * call. | |
167 | */ | |
168 | int of_dma_router_register(struct device_node *np, | |
169 | void *(*of_dma_route_allocate) | |
170 | (struct of_phandle_args *, struct of_dma *), | |
171 | struct dma_router *dma_router) | |
172 | { | |
173 | struct of_dma *ofdma; | |
174 | ||
175 | if (!np || !of_dma_route_allocate || !dma_router) { | |
176 | pr_err("%s: not enough information provided\n", __func__); | |
177 | return -EINVAL; | |
178 | } | |
179 | ||
180 | ofdma = kzalloc(sizeof(*ofdma), GFP_KERNEL); | |
181 | if (!ofdma) | |
182 | return -ENOMEM; | |
183 | ||
184 | ofdma->of_node = np; | |
185 | ofdma->of_dma_xlate = of_dma_router_xlate; | |
186 | ofdma->of_dma_route_allocate = of_dma_route_allocate; | |
187 | ofdma->dma_router = dma_router; | |
188 | ||
189 | /* Now queue of_dma controller structure in list */ | |
190 | mutex_lock(&of_dma_lock); | |
191 | list_add_tail(&ofdma->of_dma_controllers, &of_dma_list); | |
192 | mutex_unlock(&of_dma_lock); | |
193 | ||
194 | return 0; | |
195 | } | |
196 | EXPORT_SYMBOL_GPL(of_dma_router_register); | |
197 | ||
aa3da644 | 198 | /** |
5ca7c109 | 199 | * of_dma_match_channel - Check if a DMA specifier matches name |
aa3da644 | 200 | * @np: device node to look for DMA channels |
5ca7c109 JH |
201 | * @name: channel name to be matched |
202 | * @index: index of DMA specifier in list of DMA specifiers | |
aa3da644 JH |
203 | * @dma_spec: pointer to DMA specifier as found in the device tree |
204 | * | |
5ca7c109 JH |
205 | * Check if the DMA specifier pointed to by the index in a list of DMA |
206 | * specifiers, matches the name provided. Returns 0 if the name matches and | |
207 | * a valid pointer to the DMA specifier is found. Otherwise returns -ENODEV. | |
aa3da644 | 208 | */ |
bef29ec5 MP |
209 | static int of_dma_match_channel(struct device_node *np, const char *name, |
210 | int index, struct of_phandle_args *dma_spec) | |
aa3da644 | 211 | { |
aa3da644 JH |
212 | const char *s; |
213 | ||
5ca7c109 JH |
214 | if (of_property_read_string_index(np, "dma-names", index, &s)) |
215 | return -ENODEV; | |
aa3da644 | 216 | |
5ca7c109 JH |
217 | if (strcmp(name, s)) |
218 | return -ENODEV; | |
aa3da644 | 219 | |
5ca7c109 JH |
220 | if (of_parse_phandle_with_args(np, "dmas", "#dma-cells", index, |
221 | dma_spec)) | |
222 | return -ENODEV; | |
aa3da644 | 223 | |
5ca7c109 | 224 | return 0; |
aa3da644 JH |
225 | } |
226 | ||
227 | /** | |
228 | * of_dma_request_slave_channel - Get the DMA slave channel | |
229 | * @np: device node to get DMA request from | |
230 | * @name: name of desired channel | |
231 | * | |
0ad7c000 | 232 | * Returns pointer to appropriate DMA channel on success or an error pointer. |
aa3da644 JH |
233 | */ |
234 | struct dma_chan *of_dma_request_slave_channel(struct device_node *np, | |
bef29ec5 | 235 | const char *name) |
aa3da644 JH |
236 | { |
237 | struct of_phandle_args dma_spec; | |
238 | struct of_dma *ofdma; | |
239 | struct dma_chan *chan; | |
20ea6be6 | 240 | int count, i, start; |
0ad7c000 | 241 | int ret_no_channel = -ENODEV; |
20ea6be6 | 242 | static atomic_t last_index; |
aa3da644 JH |
243 | |
244 | if (!np || !name) { | |
245 | pr_err("%s: not enough information provided\n", __func__); | |
0ad7c000 | 246 | return ERR_PTR(-ENODEV); |
aa3da644 JH |
247 | } |
248 | ||
c914570f WS |
249 | /* Silently fail if there is not even the "dmas" property */ |
250 | if (!of_find_property(np, "dmas", NULL)) | |
251 | return ERR_PTR(-ENODEV); | |
252 | ||
5ca7c109 JH |
253 | count = of_property_count_strings(np, "dma-names"); |
254 | if (count < 0) { | |
c6c93048 RH |
255 | pr_err("%s: dma-names property of node '%pOF' missing or empty\n", |
256 | __func__, np); | |
0ad7c000 | 257 | return ERR_PTR(-ENODEV); |
5ca7c109 JH |
258 | } |
259 | ||
20ea6be6 NS |
260 | /* |
261 | * approximate an average distribution across multiple | |
262 | * entries with the same name | |
263 | */ | |
264 | start = atomic_inc_return(&last_index); | |
5ca7c109 | 265 | for (i = 0; i < count; i++) { |
20ea6be6 NS |
266 | if (of_dma_match_channel(np, name, |
267 | (i + start) % count, | |
268 | &dma_spec)) | |
5ca7c109 | 269 | continue; |
aa3da644 | 270 | |
de61608a LPC |
271 | mutex_lock(&of_dma_lock); |
272 | ofdma = of_dma_find_controller(&dma_spec); | |
aa3da644 | 273 | |
0ad7c000 | 274 | if (ofdma) { |
f22eb140 | 275 | chan = ofdma->of_dma_xlate(&dma_spec, ofdma); |
0ad7c000 SW |
276 | } else { |
277 | ret_no_channel = -EPROBE_DEFER; | |
f22eb140 | 278 | chan = NULL; |
0ad7c000 | 279 | } |
de61608a LPC |
280 | |
281 | mutex_unlock(&of_dma_lock); | |
9743a3b6 | 282 | |
aa3da644 JH |
283 | of_node_put(dma_spec.np); |
284 | ||
5ca7c109 JH |
285 | if (chan) |
286 | return chan; | |
287 | } | |
aa3da644 | 288 | |
0ad7c000 | 289 | return ERR_PTR(ret_no_channel); |
aa3da644 | 290 | } |
0aed1124 | 291 | EXPORT_SYMBOL_GPL(of_dma_request_slave_channel); |
aa3da644 JH |
292 | |
293 | /** | |
294 | * of_dma_simple_xlate - Simple DMA engine translation function | |
295 | * @dma_spec: pointer to DMA specifier as found in the device tree | |
296 | * @of_dma: pointer to DMA controller data | |
297 | * | |
298 | * A simple translation function for devices that use a 32-bit value for the | |
299 | * filter_param when calling the DMA engine dma_request_channel() function. | |
300 | * Note that this translation function requires that #dma-cells is equal to 1 | |
301 | * and the argument of the dma specifier is the 32-bit filter_param. Returns | |
302 | * pointer to appropriate dma channel on success or NULL on error. | |
303 | */ | |
304 | struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec, | |
305 | struct of_dma *ofdma) | |
306 | { | |
307 | int count = dma_spec->args_count; | |
308 | struct of_dma_filter_info *info = ofdma->of_dma_data; | |
309 | ||
310 | if (!info || !info->filter_fn) | |
311 | return NULL; | |
312 | ||
313 | if (count != 1) | |
314 | return NULL; | |
315 | ||
316 | return dma_request_channel(info->dma_cap, info->filter_fn, | |
317 | &dma_spec->args[0]); | |
318 | } | |
319 | EXPORT_SYMBOL_GPL(of_dma_simple_xlate); | |
16369efb AP |
320 | |
321 | /** | |
322 | * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id | |
323 | * @dma_spec: pointer to DMA specifier as found in the device tree | |
324 | * @of_dma: pointer to DMA controller data | |
325 | * | |
326 | * This function can be used as the of xlate callback for DMA driver which wants | |
327 | * to match the channel based on the channel id. When using this xlate function | |
328 | * the #dma-cells propety of the DMA controller dt node needs to be set to 1. | |
329 | * The data parameter of of_dma_controller_register must be a pointer to the | |
330 | * dma_device struct the function should match upon. | |
331 | * | |
332 | * Returns pointer to appropriate dma channel on success or NULL on error. | |
333 | */ | |
334 | struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec, | |
335 | struct of_dma *ofdma) | |
336 | { | |
337 | struct dma_device *dev = ofdma->of_dma_data; | |
338 | struct dma_chan *chan, *candidate = NULL; | |
339 | ||
340 | if (!dev || dma_spec->args_count != 1) | |
341 | return NULL; | |
342 | ||
343 | list_for_each_entry(chan, &dev->channels, device_node) | |
344 | if (chan->chan_id == dma_spec->args[0]) { | |
345 | candidate = chan; | |
346 | break; | |
347 | } | |
348 | ||
349 | if (!candidate) | |
350 | return NULL; | |
351 | ||
352 | return dma_get_slave_channel(candidate); | |
353 | } | |
354 | EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id); |