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Linux/arch/sh/drivers/dma/dma-api.c

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  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/seq_file.h>
 17 #include <linux/list.h>
 18 #include <linux/platform_device.h>
 19 #include <linux/mm.h>
 20 #include <linux/sched.h>
 21 #include <linux/slab.h>
 22 #include <asm/dma.h>
 23 
 24 DEFINE_SPINLOCK(dma_spin_lock);
 25 static LIST_HEAD(registered_dmac_list);
 26 
 27 struct dma_info *get_dma_info(unsigned int chan)
 28 {
 29         struct dma_info *info;
 30 
 31         /*
 32          * Look for each DMAC's range to determine who the owner of
 33          * the channel is.
 34          */
 35         list_for_each_entry(info, &registered_dmac_list, list) {
 36                 if ((chan <  info->first_vchannel_nr) ||
 37                     (chan >= info->first_vchannel_nr + info->nr_channels))
 38                         continue;
 39 
 40                 return info;
 41         }
 42 
 43         return NULL;
 44 }
 45 EXPORT_SYMBOL(get_dma_info);
 46 
 47 struct dma_info *get_dma_info_by_name(const char *dmac_name)
 48 {
 49         struct dma_info *info;
 50 
 51         list_for_each_entry(info, &registered_dmac_list, list) {
 52                 if (dmac_name && (strcmp(dmac_name, info->name) != 0))
 53                         continue;
 54                 else
 55                         return info;
 56         }
 57 
 58         return NULL;
 59 }
 60 EXPORT_SYMBOL(get_dma_info_by_name);
 61 
 62 static unsigned int get_nr_channels(void)
 63 {
 64         struct dma_info *info;
 65         unsigned int nr = 0;
 66 
 67         if (unlikely(list_empty(&registered_dmac_list)))
 68                 return nr;
 69 
 70         list_for_each_entry(info, &registered_dmac_list, list)
 71                 nr += info->nr_channels;
 72 
 73         return nr;
 74 }
 75 
 76 struct dma_channel *get_dma_channel(unsigned int chan)
 77 {
 78         struct dma_info *info = get_dma_info(chan);
 79         struct dma_channel *channel;
 80         int i;
 81 
 82         if (unlikely(!info))
 83                 return ERR_PTR(-EINVAL);
 84 
 85         for (i = 0; i < info->nr_channels; i++) {
 86                 channel = &info->channels[i];
 87                 if (channel->vchan == chan)
 88                         return channel;
 89         }
 90 
 91         return NULL;
 92 }
 93 EXPORT_SYMBOL(get_dma_channel);
 94 
 95 int get_dma_residue(unsigned int chan)
 96 {
 97         struct dma_info *info = get_dma_info(chan);
 98         struct dma_channel *channel = get_dma_channel(chan);
 99 
100         if (info->ops->get_residue)
101                 return info->ops->get_residue(channel);
102 
103         return 0;
104 }
105 EXPORT_SYMBOL(get_dma_residue);
106 
107 static int search_cap(const char **haystack, const char *needle)
108 {
109         const char **p;
110 
111         for (p = haystack; *p; p++)
112                 if (strcmp(*p, needle) == 0)
113                         return 1;
114 
115         return 0;
116 }
117 
118 /**
119  * request_dma_bycap - Allocate a DMA channel based on its capabilities
120  * @dmac: List of DMA controllers to search
121  * @caps: List of capabilities
122  *
123  * Search all channels of all DMA controllers to find a channel which
124  * matches the requested capabilities. The result is the channel
125  * number if a match is found, or %-ENODEV if no match is found.
126  *
127  * Note that not all DMA controllers export capabilities, in which
128  * case they can never be allocated using this API, and so
129  * request_dma() must be used specifying the channel number.
130  */
131 int request_dma_bycap(const char **dmac, const char **caps, const char *dev_id)
132 {
133         unsigned int found = 0;
134         struct dma_info *info;
135         const char **p;
136         int i;
137 
138         BUG_ON(!dmac || !caps);
139 
140         list_for_each_entry(info, &registered_dmac_list, list)
141                 if (strcmp(*dmac, info->name) == 0) {
142                         found = 1;
143                         break;
144                 }
145 
146         if (!found)
147                 return -ENODEV;
148 
149         for (i = 0; i < info->nr_channels; i++) {
150                 struct dma_channel *channel = &info->channels[i];
151 
152                 if (unlikely(!channel->caps))
153                         continue;
154 
155                 for (p = caps; *p; p++) {
156                         if (!search_cap(channel->caps, *p))
157                                 break;
158                         if (request_dma(channel->chan, dev_id) == 0)
159                                 return channel->chan;
160                 }
161         }
162 
163         return -EINVAL;
164 }
165 EXPORT_SYMBOL(request_dma_bycap);
166 
167 int dmac_search_free_channel(const char *dev_id)
168 {
169         struct dma_channel *channel = { 0 };
170         struct dma_info *info = get_dma_info(0);
171         int i;
172 
173         for (i = 0; i < info->nr_channels; i++) {
174                 channel = &info->channels[i];
175                 if (unlikely(!channel))
176                         return -ENODEV;
177 
178                 if (atomic_read(&channel->busy) == 0)
179                         break;
180         }
181 
182         if (info->ops->request) {
183                 int result = info->ops->request(channel);
184                 if (result)
185                         return result;
186 
187                 atomic_set(&channel->busy, 1);
188                 return channel->chan;
189         }
190 
191         return -ENOSYS;
192 }
193 
194 int request_dma(unsigned int chan, const char *dev_id)
195 {
196         struct dma_channel *channel = { 0 };
197         struct dma_info *info = get_dma_info(chan);
198         int result;
199 
200         channel = get_dma_channel(chan);
201         if (atomic_xchg(&channel->busy, 1))
202                 return -EBUSY;
203 
204         strlcpy(channel->dev_id, dev_id, sizeof(channel->dev_id));
205 
206         if (info->ops->request) {
207                 result = info->ops->request(channel);
208                 if (result)
209                         atomic_set(&channel->busy, 0);
210 
211                 return result;
212         }
213 
214         return 0;
215 }
216 EXPORT_SYMBOL(request_dma);
217 
218 void free_dma(unsigned int chan)
219 {
220         struct dma_info *info = get_dma_info(chan);
221         struct dma_channel *channel = get_dma_channel(chan);
222 
223         if (info->ops->free)
224                 info->ops->free(channel);
225 
226         atomic_set(&channel->busy, 0);
227 }
228 EXPORT_SYMBOL(free_dma);
229 
230 void dma_wait_for_completion(unsigned int chan)
231 {
232         struct dma_info *info = get_dma_info(chan);
233         struct dma_channel *channel = get_dma_channel(chan);
234 
235         if (channel->flags & DMA_TEI_CAPABLE) {
236                 wait_event(channel->wait_queue,
237                            (info->ops->get_residue(channel) == 0));
238                 return;
239         }
240 
241         while (info->ops->get_residue(channel))
242                 cpu_relax();
243 }
244 EXPORT_SYMBOL(dma_wait_for_completion);
245 
246 int register_chan_caps(const char *dmac, struct dma_chan_caps *caps)
247 {
248         struct dma_info *info;
249         unsigned int found = 0;
250         int i;
251 
252         list_for_each_entry(info, &registered_dmac_list, list)
253                 if (strcmp(dmac, info->name) == 0) {
254                         found = 1;
255                         break;
256                 }
257 
258         if (unlikely(!found))
259                 return -ENODEV;
260 
261         for (i = 0; i < info->nr_channels; i++, caps++) {
262                 struct dma_channel *channel;
263 
264                 if ((info->first_channel_nr + i) != caps->ch_num)
265                         return -EINVAL;
266 
267                 channel = &info->channels[i];
268                 channel->caps = caps->caplist;
269         }
270 
271         return 0;
272 }
273 EXPORT_SYMBOL(register_chan_caps);
274 
275 void dma_configure_channel(unsigned int chan, unsigned long flags)
276 {
277         struct dma_info *info = get_dma_info(chan);
278         struct dma_channel *channel = get_dma_channel(chan);
279 
280         if (info->ops->configure)
281                 info->ops->configure(channel, flags);
282 }
283 EXPORT_SYMBOL(dma_configure_channel);
284 
285 int dma_xfer(unsigned int chan, unsigned long from,
286              unsigned long to, size_t size, unsigned int mode)
287 {
288         struct dma_info *info = get_dma_info(chan);
289         struct dma_channel *channel = get_dma_channel(chan);
290 
291         channel->sar    = from;
292         channel->dar    = to;
293         channel->count  = size;
294         channel->mode   = mode;
295 
296         return info->ops->xfer(channel);
297 }
298 EXPORT_SYMBOL(dma_xfer);
299 
300 int dma_extend(unsigned int chan, unsigned long op, void *param)
301 {
302         struct dma_info *info = get_dma_info(chan);
303         struct dma_channel *channel = get_dma_channel(chan);
304 
305         if (info->ops->extend)
306                 return info->ops->extend(channel, op, param);
307 
308         return -ENOSYS;
309 }
310 EXPORT_SYMBOL(dma_extend);
311 
312 static int dma_proc_show(struct seq_file *m, void *v)
313 {
314         struct dma_info *info = v;
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                         seq_printf(m, "%2d: %14s    %s\n", i,
335                                    info->name, channel->dev_id);
336                 }
337         }
338 
339         return 0;
340 }
341 
342 static int dma_proc_open(struct inode *inode, struct file *file)
343 {
344         return single_open(file, dma_proc_show, NULL);
345 }
346 
347 static const struct file_operations dma_proc_fops = {
348         .open           = dma_proc_open,
349         .read           = seq_read,
350         .llseek         = seq_lseek,
351         .release        = single_release,
352 };
353 
354 int register_dmac(struct dma_info *info)
355 {
356         unsigned int total_channels, i;
357 
358         INIT_LIST_HEAD(&info->list);
359 
360         printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n",
361                info->name, info->nr_channels, info->nr_channels > 1 ? "s" : "");
362 
363         BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels);
364 
365         info->pdev = platform_device_register_simple(info->name, -1,
366                                                      NULL, 0);
367         if (IS_ERR(info->pdev))
368                 return PTR_ERR(info->pdev);
369 
370         /*
371          * Don't touch pre-configured channels
372          */
373         if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) {
374                 unsigned int size;
375 
376                 size = sizeof(struct dma_channel) * info->nr_channels;
377 
378                 info->channels = kzalloc(size, GFP_KERNEL);
379                 if (!info->channels)
380                         return -ENOMEM;
381         }
382 
383         total_channels = get_nr_channels();
384         info->first_vchannel_nr = total_channels;
385         for (i = 0; i < info->nr_channels; i++) {
386                 struct dma_channel *chan = &info->channels[i];
387 
388                 atomic_set(&chan->busy, 0);
389 
390                 chan->chan  = info->first_channel_nr + i;
391                 chan->vchan = info->first_channel_nr + i + total_channels;
392 
393                 memcpy(chan->dev_id, "Unused", 7);
394 
395                 if (info->flags & DMAC_CHANNELS_TEI_CAPABLE)
396                         chan->flags |= DMA_TEI_CAPABLE;
397 
398                 init_waitqueue_head(&chan->wait_queue);
399                 dma_create_sysfs_files(chan, info);
400         }
401 
402         list_add(&info->list, &registered_dmac_list);
403 
404         return 0;
405 }
406 EXPORT_SYMBOL(register_dmac);
407 
408 void unregister_dmac(struct dma_info *info)
409 {
410         unsigned int i;
411 
412         for (i = 0; i < info->nr_channels; i++)
413                 dma_remove_sysfs_files(info->channels + i, info);
414 
415         if (!(info->flags & DMAC_CHANNELS_CONFIGURED))
416                 kfree(info->channels);
417 
418         list_del(&info->list);
419         platform_device_unregister(info->pdev);
420 }
421 EXPORT_SYMBOL(unregister_dmac);
422 
423 static int __init dma_api_init(void)
424 {
425         printk(KERN_NOTICE "DMA: Registering DMA API.\n");
426         return proc_create("dma", 0, NULL, &dma_proc_fops) ? 0 : -ENOMEM;
427 }
428 subsys_initcall(dma_api_init);
429 
430 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
431 MODULE_DESCRIPTION("DMA API for SuperH");
432 MODULE_LICENSE("GPL");
433 

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