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