Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
[pandora-kernel.git] / arch / sh / drivers / dma / dma-api.c
1 /*
2  * arch/sh/drivers/dma/dma-api.c
3  *
4  * SuperH-specific DMA management API
5  *
6  * Copyright (C) 2003, 2004, 2005  Paul Mundt
7  *
8  * This file is subject to the terms and conditions of the GNU General Public
9  * License.  See the file "COPYING" in the main directory of this archive
10  * for more details.
11  */
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/spinlock.h>
15 #include <linux/proc_fs.h>
16 #include <linux/list.h>
17 #include <linux/platform_device.h>
18 #include <linux/mm.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <asm/dma.h>
22
23 DEFINE_SPINLOCK(dma_spin_lock);
24 static LIST_HEAD(registered_dmac_list);
25
26 struct dma_info *get_dma_info(unsigned int chan)
27 {
28         struct dma_info *info;
29
30         /*
31          * Look for each DMAC's range to determine who the owner of
32          * the channel is.
33          */
34         list_for_each_entry(info, &registered_dmac_list, list) {
35                 if ((chan <  info->first_vchannel_nr) ||
36                     (chan >= info->first_vchannel_nr + info->nr_channels))
37                         continue;
38
39                 return info;
40         }
41
42         return NULL;
43 }
44 EXPORT_SYMBOL(get_dma_info);
45
46 struct dma_info *get_dma_info_by_name(const char *dmac_name)
47 {
48         struct dma_info *info;
49
50         list_for_each_entry(info, &registered_dmac_list, list) {
51                 if (dmac_name && (strcmp(dmac_name, info->name) != 0))
52                         continue;
53                 else
54                         return info;
55         }
56
57         return NULL;
58 }
59 EXPORT_SYMBOL(get_dma_info_by_name);
60
61 static unsigned int get_nr_channels(void)
62 {
63         struct dma_info *info;
64         unsigned int nr = 0;
65
66         if (unlikely(list_empty(&registered_dmac_list)))
67                 return nr;
68
69         list_for_each_entry(info, &registered_dmac_list, list)
70                 nr += info->nr_channels;
71
72         return nr;
73 }
74
75 struct dma_channel *get_dma_channel(unsigned int chan)
76 {
77         struct dma_info *info = get_dma_info(chan);
78         struct dma_channel *channel;
79         int i;
80
81         if (unlikely(!info))
82                 return ERR_PTR(-EINVAL);
83
84         for (i = 0; i < info->nr_channels; i++) {
85                 channel = &info->channels[i];
86                 if (channel->vchan == chan)
87                         return channel;
88         }
89
90         return NULL;
91 }
92 EXPORT_SYMBOL(get_dma_channel);
93
94 int get_dma_residue(unsigned int chan)
95 {
96         struct dma_info *info = get_dma_info(chan);
97         struct dma_channel *channel = get_dma_channel(chan);
98
99         if (info->ops->get_residue)
100                 return info->ops->get_residue(channel);
101
102         return 0;
103 }
104 EXPORT_SYMBOL(get_dma_residue);
105
106 static int search_cap(const char **haystack, const char *needle)
107 {
108         const char **p;
109
110         for (p = haystack; *p; p++)
111                 if (strcmp(*p, needle) == 0)
112                         return 1;
113
114         return 0;
115 }
116
117 /**
118  * request_dma_bycap - Allocate a DMA channel based on its capabilities
119  * @dmac: List of DMA controllers to search
120  * @caps: List of capabilities
121  *
122  * Search all channels of all DMA controllers to find a channel which
123  * matches the requested capabilities. The result is the channel
124  * number if a match is found, or %-ENODEV if no match is found.
125  *
126  * Note that not all DMA controllers export capabilities, in which
127  * case they can never be allocated using this API, and so
128  * request_dma() must be used specifying the channel number.
129  */
130 int request_dma_bycap(const char **dmac, const char **caps, const char *dev_id)
131 {
132         unsigned int found = 0;
133         struct dma_info *info;
134         const char **p;
135         int i;
136
137         BUG_ON(!dmac || !caps);
138
139         list_for_each_entry(info, &registered_dmac_list, list)
140                 if (strcmp(*dmac, info->name) == 0) {
141                         found = 1;
142                         break;
143                 }
144
145         if (!found)
146                 return -ENODEV;
147
148         for (i = 0; i < info->nr_channels; i++) {
149                 struct dma_channel *channel = &info->channels[i];
150
151                 if (unlikely(!channel->caps))
152                         continue;
153
154                 for (p = caps; *p; p++) {
155                         if (!search_cap(channel->caps, *p))
156                                 break;
157                         if (request_dma(channel->chan, dev_id) == 0)
158                                 return channel->chan;
159                 }
160         }
161
162         return -EINVAL;
163 }
164 EXPORT_SYMBOL(request_dma_bycap);
165
166 int dmac_search_free_channel(const char *dev_id)
167 {
168         struct dma_channel *channel = { 0 };
169         struct dma_info *info = get_dma_info(0);
170         int i;
171
172         for (i = 0; i < info->nr_channels; i++) {
173                 channel = &info->channels[i];
174                 if (unlikely(!channel))
175                         return -ENODEV;
176
177                 if (atomic_read(&channel->busy) == 0)
178                         break;
179         }
180
181         if (info->ops->request) {
182                 int result = info->ops->request(channel);
183                 if (result)
184                         return result;
185
186                 atomic_set(&channel->busy, 1);
187                 return channel->chan;
188         }
189
190         return -ENOSYS;
191 }
192
193 int request_dma(unsigned int chan, const char *dev_id)
194 {
195         struct dma_channel *channel = { 0 };
196         struct dma_info *info = get_dma_info(chan);
197         int result;
198
199         channel = get_dma_channel(chan);
200         if (atomic_xchg(&channel->busy, 1))
201                 return -EBUSY;
202
203         strlcpy(channel->dev_id, dev_id, sizeof(channel->dev_id));
204
205         if (info->ops->request) {
206                 result = info->ops->request(channel);
207                 if (result)
208                         atomic_set(&channel->busy, 0);
209
210                 return result;
211         }
212
213         return 0;
214 }
215 EXPORT_SYMBOL(request_dma);
216
217 void free_dma(unsigned int chan)
218 {
219         struct dma_info *info = get_dma_info(chan);
220         struct dma_channel *channel = get_dma_channel(chan);
221
222         if (info->ops->free)
223                 info->ops->free(channel);
224
225         atomic_set(&channel->busy, 0);
226 }
227 EXPORT_SYMBOL(free_dma);
228
229 void dma_wait_for_completion(unsigned int chan)
230 {
231         struct dma_info *info = get_dma_info(chan);
232         struct dma_channel *channel = get_dma_channel(chan);
233
234         if (channel->flags & DMA_TEI_CAPABLE) {
235                 wait_event(channel->wait_queue,
236                            (info->ops->get_residue(channel) == 0));
237                 return;
238         }
239
240         while (info->ops->get_residue(channel))
241                 cpu_relax();
242 }
243 EXPORT_SYMBOL(dma_wait_for_completion);
244
245 int register_chan_caps(const char *dmac, struct dma_chan_caps *caps)
246 {
247         struct dma_info *info;
248         unsigned int found = 0;
249         int i;
250
251         list_for_each_entry(info, &registered_dmac_list, list)
252                 if (strcmp(dmac, info->name) == 0) {
253                         found = 1;
254                         break;
255                 }
256
257         if (unlikely(!found))
258                 return -ENODEV;
259
260         for (i = 0; i < info->nr_channels; i++, caps++) {
261                 struct dma_channel *channel;
262
263                 if ((info->first_channel_nr + i) != caps->ch_num)
264                         return -EINVAL;
265
266                 channel = &info->channels[i];
267                 channel->caps = caps->caplist;
268         }
269
270         return 0;
271 }
272 EXPORT_SYMBOL(register_chan_caps);
273
274 void dma_configure_channel(unsigned int chan, unsigned long flags)
275 {
276         struct dma_info *info = get_dma_info(chan);
277         struct dma_channel *channel = get_dma_channel(chan);
278
279         if (info->ops->configure)
280                 info->ops->configure(channel, flags);
281 }
282 EXPORT_SYMBOL(dma_configure_channel);
283
284 int dma_xfer(unsigned int chan, unsigned long from,
285              unsigned long to, size_t size, unsigned int mode)
286 {
287         struct dma_info *info = get_dma_info(chan);
288         struct dma_channel *channel = get_dma_channel(chan);
289
290         channel->sar    = from;
291         channel->dar    = to;
292         channel->count  = size;
293         channel->mode   = mode;
294
295         return info->ops->xfer(channel);
296 }
297 EXPORT_SYMBOL(dma_xfer);
298
299 int dma_extend(unsigned int chan, unsigned long op, void *param)
300 {
301         struct dma_info *info = get_dma_info(chan);
302         struct dma_channel *channel = get_dma_channel(chan);
303
304         if (info->ops->extend)
305                 return info->ops->extend(channel, op, param);
306
307         return -ENOSYS;
308 }
309 EXPORT_SYMBOL(dma_extend);
310
311 static int dma_read_proc(char *buf, char **start, off_t off,
312                          int len, int *eof, void *data)
313 {
314         struct dma_info *info;
315         char *p = buf;
316
317         if (list_empty(&registered_dmac_list))
318                 return 0;
319
320         /*
321          * Iterate over each registered DMAC
322          */
323         list_for_each_entry(info, &registered_dmac_list, list) {
324                 int i;
325
326                 /*
327                  * Iterate over each channel
328                  */
329                 for (i = 0; i < info->nr_channels; i++) {
330                         struct dma_channel *channel = info->channels + i;
331
332                         if (!(channel->flags & DMA_CONFIGURED))
333                                 continue;
334
335                         p += sprintf(p, "%2d: %14s    %s\n", i,
336                                      info->name, channel->dev_id);
337                 }
338         }
339
340         return p - buf;
341 }
342
343 int register_dmac(struct dma_info *info)
344 {
345         unsigned int total_channels, i;
346
347         INIT_LIST_HEAD(&info->list);
348
349         printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n",
350                info->name, info->nr_channels, info->nr_channels > 1 ? "s" : "");
351
352         BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels);
353
354         info->pdev = platform_device_register_simple(info->name, -1,
355                                                      NULL, 0);
356         if (IS_ERR(info->pdev))
357                 return PTR_ERR(info->pdev);
358
359         /*
360          * Don't touch pre-configured channels
361          */
362         if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) {
363                 unsigned int size;
364
365                 size = sizeof(struct dma_channel) * info->nr_channels;
366
367                 info->channels = kzalloc(size, GFP_KERNEL);
368                 if (!info->channels)
369                         return -ENOMEM;
370         }
371
372         total_channels = get_nr_channels();
373         info->first_vchannel_nr = total_channels;
374         for (i = 0; i < info->nr_channels; i++) {
375                 struct dma_channel *chan = &info->channels[i];
376
377                 atomic_set(&chan->busy, 0);
378
379                 chan->chan  = info->first_channel_nr + i;
380                 chan->vchan = info->first_channel_nr + i + total_channels;
381
382                 memcpy(chan->dev_id, "Unused", 7);
383
384                 if (info->flags & DMAC_CHANNELS_TEI_CAPABLE)
385                         chan->flags |= DMA_TEI_CAPABLE;
386
387                 init_waitqueue_head(&chan->wait_queue);
388                 dma_create_sysfs_files(chan, info);
389         }
390
391         list_add(&info->list, &registered_dmac_list);
392
393         return 0;
394 }
395 EXPORT_SYMBOL(register_dmac);
396
397 void unregister_dmac(struct dma_info *info)
398 {
399         unsigned int i;
400
401         for (i = 0; i < info->nr_channels; i++)
402                 dma_remove_sysfs_files(info->channels + i, info);
403
404         if (!(info->flags & DMAC_CHANNELS_CONFIGURED))
405                 kfree(info->channels);
406
407         list_del(&info->list);
408         platform_device_unregister(info->pdev);
409 }
410 EXPORT_SYMBOL(unregister_dmac);
411
412 static int __init dma_api_init(void)
413 {
414         printk(KERN_NOTICE "DMA: Registering DMA API.\n");
415         create_proc_read_entry("dma", 0, 0, dma_read_proc, 0);
416         return 0;
417 }
418 subsys_initcall(dma_api_init);
419
420 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
421 MODULE_DESCRIPTION("DMA API for SuperH");
422 MODULE_LICENSE("GPL");