1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * arch/sh/drivers/dma/dma-api.c
4 *
5 * SuperH-specific DMA management API
6 *
7 * Copyright (C) 2003, 2004, 2005 Paul Mundt
8 */
9 #include <linux/init.h>
10 #include <linux/module.h>
11 #include <linux/spinlock.h>
12 #include <linux/proc_fs.h>
13 #include <linux/seq_file.h>
14 #include <linux/list.h>
15 #include <linux/platform_device.h>
16 #include <linux/mm.h>
17 #include <linux/sched.h>
18 #include <linux/slab.h>
19 #include <asm/dma.h>
20
21 DEFINE_SPINLOCK(dma_spin_lock);
22 static LIST_HEAD(registered_dmac_list);
23
get_dma_info(unsigned int chan)24 struct dma_info *get_dma_info(unsigned int chan)
25 {
26 struct dma_info *info;
27
28 /*
29 * Look for each DMAC's range to determine who the owner of
30 * the channel is.
31 */
32 list_for_each_entry(info, ®istered_dmac_list, list) {
33 if ((chan < info->first_vchannel_nr) ||
34 (chan >= info->first_vchannel_nr + info->nr_channels))
35 continue;
36
37 return info;
38 }
39
40 return NULL;
41 }
42 EXPORT_SYMBOL(get_dma_info);
43
get_dma_info_by_name(const char * dmac_name)44 struct dma_info *get_dma_info_by_name(const char *dmac_name)
45 {
46 struct dma_info *info;
47
48 list_for_each_entry(info, ®istered_dmac_list, list) {
49 if (dmac_name && (strcmp(dmac_name, info->name) != 0))
50 continue;
51 else
52 return info;
53 }
54
55 return NULL;
56 }
57 EXPORT_SYMBOL(get_dma_info_by_name);
58
get_nr_channels(void)59 static unsigned int get_nr_channels(void)
60 {
61 struct dma_info *info;
62 unsigned int nr = 0;
63
64 if (unlikely(list_empty(®istered_dmac_list)))
65 return nr;
66
67 list_for_each_entry(info, ®istered_dmac_list, list)
68 nr += info->nr_channels;
69
70 return nr;
71 }
72
get_dma_channel(unsigned int chan)73 struct dma_channel *get_dma_channel(unsigned int chan)
74 {
75 struct dma_info *info = get_dma_info(chan);
76 struct dma_channel *channel;
77 int i;
78
79 if (unlikely(!info))
80 return ERR_PTR(-EINVAL);
81
82 for (i = 0; i < info->nr_channels; i++) {
83 channel = &info->channels[i];
84 if (channel->vchan == chan)
85 return channel;
86 }
87
88 return NULL;
89 }
90 EXPORT_SYMBOL(get_dma_channel);
91
get_dma_residue(unsigned int chan)92 int get_dma_residue(unsigned int chan)
93 {
94 struct dma_info *info = get_dma_info(chan);
95 struct dma_channel *channel = get_dma_channel(chan);
96
97 if (info->ops->get_residue)
98 return info->ops->get_residue(channel);
99
100 return 0;
101 }
102 EXPORT_SYMBOL(get_dma_residue);
103
search_cap(const char ** haystack,const char * needle)104 static int search_cap(const char **haystack, const char *needle)
105 {
106 const char **p;
107
108 for (p = haystack; *p; p++)
109 if (strcmp(*p, needle) == 0)
110 return 1;
111
112 return 0;
113 }
114
115 /**
116 * request_dma_bycap - Allocate a DMA channel based on its capabilities
117 * @dmac: List of DMA controllers to search
118 * @caps: List of capabilities
119 *
120 * Search all channels of all DMA controllers to find a channel which
121 * matches the requested capabilities. The result is the channel
122 * number if a match is found, or %-ENODEV if no match is found.
123 *
124 * Note that not all DMA controllers export capabilities, in which
125 * case they can never be allocated using this API, and so
126 * request_dma() must be used specifying the channel number.
127 */
request_dma_bycap(const char ** dmac,const char ** caps,const char * dev_id)128 int request_dma_bycap(const char **dmac, const char **caps, const char *dev_id)
129 {
130 unsigned int found = 0;
131 struct dma_info *info;
132 const char **p;
133 int i;
134
135 BUG_ON(!dmac || !caps);
136
137 list_for_each_entry(info, ®istered_dmac_list, list)
138 if (strcmp(*dmac, info->name) == 0) {
139 found = 1;
140 break;
141 }
142
143 if (!found)
144 return -ENODEV;
145
146 for (i = 0; i < info->nr_channels; i++) {
147 struct dma_channel *channel = &info->channels[i];
148
149 if (unlikely(!channel->caps))
150 continue;
151
152 for (p = caps; *p; p++) {
153 if (!search_cap(channel->caps, *p))
154 break;
155 if (request_dma(channel->chan, dev_id) == 0)
156 return channel->chan;
157 }
158 }
159
160 return -EINVAL;
161 }
162 EXPORT_SYMBOL(request_dma_bycap);
163
dmac_search_free_channel(const char * dev_id)164 int dmac_search_free_channel(const char *dev_id)
165 {
166 struct dma_channel *channel = { 0 };
167 struct dma_info *info = get_dma_info(0);
168 int i;
169
170 for (i = 0; i < info->nr_channels; i++) {
171 channel = &info->channels[i];
172 if (unlikely(!channel))
173 return -ENODEV;
174
175 if (atomic_read(&channel->busy) == 0)
176 break;
177 }
178
179 if (info->ops->request) {
180 int result = info->ops->request(channel);
181 if (result)
182 return result;
183
184 atomic_set(&channel->busy, 1);
185 return channel->chan;
186 }
187
188 return -ENOSYS;
189 }
190
request_dma(unsigned int chan,const char * dev_id)191 int request_dma(unsigned int chan, const char *dev_id)
192 {
193 struct dma_channel *channel = { 0 };
194 struct dma_info *info = get_dma_info(chan);
195 int result;
196
197 channel = get_dma_channel(chan);
198 if (atomic_xchg(&channel->busy, 1))
199 return -EBUSY;
200
201 strscpy(channel->dev_id, dev_id, sizeof(channel->dev_id));
202
203 if (info->ops->request) {
204 result = info->ops->request(channel);
205 if (result)
206 atomic_set(&channel->busy, 0);
207
208 return result;
209 }
210
211 return 0;
212 }
213 EXPORT_SYMBOL(request_dma);
214
free_dma(unsigned int chan)215 void free_dma(unsigned int chan)
216 {
217 struct dma_info *info = get_dma_info(chan);
218 struct dma_channel *channel = get_dma_channel(chan);
219
220 if (info->ops->free)
221 info->ops->free(channel);
222
223 atomic_set(&channel->busy, 0);
224 }
225 EXPORT_SYMBOL(free_dma);
226
dma_wait_for_completion(unsigned int chan)227 void dma_wait_for_completion(unsigned int chan)
228 {
229 struct dma_info *info = get_dma_info(chan);
230 struct dma_channel *channel = get_dma_channel(chan);
231
232 if (channel->flags & DMA_TEI_CAPABLE) {
233 wait_event(channel->wait_queue,
234 (info->ops->get_residue(channel) == 0));
235 return;
236 }
237
238 while (info->ops->get_residue(channel))
239 cpu_relax();
240 }
241 EXPORT_SYMBOL(dma_wait_for_completion);
242
register_chan_caps(const char * dmac,struct dma_chan_caps * caps)243 int register_chan_caps(const char *dmac, struct dma_chan_caps *caps)
244 {
245 struct dma_info *info;
246 unsigned int found = 0;
247 int i;
248
249 list_for_each_entry(info, ®istered_dmac_list, list)
250 if (strcmp(dmac, info->name) == 0) {
251 found = 1;
252 break;
253 }
254
255 if (unlikely(!found))
256 return -ENODEV;
257
258 for (i = 0; i < info->nr_channels; i++, caps++) {
259 struct dma_channel *channel;
260
261 if ((info->first_channel_nr + i) != caps->ch_num)
262 return -EINVAL;
263
264 channel = &info->channels[i];
265 channel->caps = caps->caplist;
266 }
267
268 return 0;
269 }
270 EXPORT_SYMBOL(register_chan_caps);
271
dma_configure_channel(unsigned int chan,unsigned long flags)272 void dma_configure_channel(unsigned int chan, unsigned long flags)
273 {
274 struct dma_info *info = get_dma_info(chan);
275 struct dma_channel *channel = get_dma_channel(chan);
276
277 if (info->ops->configure)
278 info->ops->configure(channel, flags);
279 }
280 EXPORT_SYMBOL(dma_configure_channel);
281
dma_xfer(unsigned int chan,unsigned long from,unsigned long to,size_t size,unsigned int mode)282 int dma_xfer(unsigned int chan, unsigned long from,
283 unsigned long to, size_t size, unsigned int mode)
284 {
285 struct dma_info *info = get_dma_info(chan);
286 struct dma_channel *channel = get_dma_channel(chan);
287
288 channel->sar = from;
289 channel->dar = to;
290 channel->count = size;
291 channel->mode = mode;
292
293 return info->ops->xfer(channel);
294 }
295 EXPORT_SYMBOL(dma_xfer);
296
dma_extend(unsigned int chan,unsigned long op,void * param)297 int dma_extend(unsigned int chan, unsigned long op, void *param)
298 {
299 struct dma_info *info = get_dma_info(chan);
300 struct dma_channel *channel = get_dma_channel(chan);
301
302 if (info->ops->extend)
303 return info->ops->extend(channel, op, param);
304
305 return -ENOSYS;
306 }
307 EXPORT_SYMBOL(dma_extend);
308
dma_proc_show(struct seq_file * m,void * v)309 static int dma_proc_show(struct seq_file *m, void *v)
310 {
311 struct dma_info *info = v;
312
313 if (list_empty(®istered_dmac_list))
314 return 0;
315
316 /*
317 * Iterate over each registered DMAC
318 */
319 list_for_each_entry(info, ®istered_dmac_list, list) {
320 int i;
321
322 /*
323 * Iterate over each channel
324 */
325 for (i = 0; i < info->nr_channels; i++) {
326 struct dma_channel *channel = info->channels + i;
327
328 if (!(channel->flags & DMA_CONFIGURED))
329 continue;
330
331 seq_printf(m, "%2d: %14s %s\n", i,
332 info->name, channel->dev_id);
333 }
334 }
335
336 return 0;
337 }
338
register_dmac(struct dma_info * info)339 int register_dmac(struct dma_info *info)
340 {
341 unsigned int total_channels, i;
342
343 INIT_LIST_HEAD(&info->list);
344
345 printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n",
346 info->name, info->nr_channels, info->nr_channels > 1 ? "s" : "");
347
348 BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels);
349
350 info->pdev = platform_device_register_simple(info->name, -1,
351 NULL, 0);
352 if (IS_ERR(info->pdev))
353 return PTR_ERR(info->pdev);
354
355 /*
356 * Don't touch pre-configured channels
357 */
358 if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) {
359 unsigned int size;
360
361 size = sizeof(struct dma_channel) * info->nr_channels;
362
363 info->channels = kzalloc(size, GFP_KERNEL);
364 if (!info->channels)
365 return -ENOMEM;
366 }
367
368 total_channels = get_nr_channels();
369 info->first_vchannel_nr = total_channels;
370 for (i = 0; i < info->nr_channels; i++) {
371 struct dma_channel *chan = &info->channels[i];
372
373 atomic_set(&chan->busy, 0);
374
375 chan->chan = info->first_channel_nr + i;
376 chan->vchan = info->first_channel_nr + i + total_channels;
377
378 memcpy(chan->dev_id, "Unused", 7);
379
380 if (info->flags & DMAC_CHANNELS_TEI_CAPABLE)
381 chan->flags |= DMA_TEI_CAPABLE;
382
383 init_waitqueue_head(&chan->wait_queue);
384 dma_create_sysfs_files(chan, info);
385 }
386
387 list_add(&info->list, ®istered_dmac_list);
388
389 return 0;
390 }
391 EXPORT_SYMBOL(register_dmac);
392
unregister_dmac(struct dma_info * info)393 void unregister_dmac(struct dma_info *info)
394 {
395 unsigned int i;
396
397 for (i = 0; i < info->nr_channels; i++)
398 dma_remove_sysfs_files(info->channels + i, info);
399
400 if (!(info->flags & DMAC_CHANNELS_CONFIGURED))
401 kfree(info->channels);
402
403 list_del(&info->list);
404 platform_device_unregister(info->pdev);
405 }
406 EXPORT_SYMBOL(unregister_dmac);
407
dma_api_init(void)408 static int __init dma_api_init(void)
409 {
410 printk(KERN_NOTICE "DMA: Registering DMA API.\n");
411 return proc_create_single("dma", 0, NULL, dma_proc_show) ? 0 : -ENOMEM;
412 }
413 subsys_initcall(dma_api_init);
414
415 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
416 MODULE_DESCRIPTION("DMA API for SuperH");
417 MODULE_LICENSE("GPL v2");
418