Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
/*
 * arch/sh/drivers/dma/dma-api.c
 *
 * SuperH-specific DMA management API
 *
 * Copyright (C) 2003, 2004, 2005  Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/proc_fs.h>
#include <linux/list.h>
#include <linux/platform_device.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <asm/dma.h>

DEFINE_SPINLOCK(dma_spin_lock);
static LIST_HEAD(registered_dmac_list);

struct dma_info *get_dma_info(unsigned int chan)
{
	struct dma_info *info;

	/*
	 * Look for each DMAC's range to determine who the owner of
	 * the channel is.
	 */
	list_for_each_entry(info, &registered_dmac_list, list) {
		if ((chan <  info->first_vchannel_nr) ||
		    (chan >= info->first_vchannel_nr + info->nr_channels))
			continue;

		return info;
	}

	return NULL;
}
EXPORT_SYMBOL(get_dma_info);

struct dma_info *get_dma_info_by_name(const char *dmac_name)
{
	struct dma_info *info;

	list_for_each_entry(info, &registered_dmac_list, list) {
		if (dmac_name && (strcmp(dmac_name, info->name) != 0))
			continue;
		else
			return info;
	}

	return NULL;
}
EXPORT_SYMBOL(get_dma_info_by_name);

static unsigned int get_nr_channels(void)
{
	struct dma_info *info;
	unsigned int nr = 0;

	if (unlikely(list_empty(&registered_dmac_list)))
		return nr;

	list_for_each_entry(info, &registered_dmac_list, list)
		nr += info->nr_channels;

	return nr;
}

struct dma_channel *get_dma_channel(unsigned int chan)
{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel;
	int i;

	if (unlikely(!info))
		return ERR_PTR(-EINVAL);

	for (i = 0; i < info->nr_channels; i++) {
		channel = &info->channels[i];
		if (channel->vchan == chan)
			return channel;
	}

	return NULL;
}
EXPORT_SYMBOL(get_dma_channel);

int get_dma_residue(unsigned int chan)
{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel = get_dma_channel(chan);

	if (info->ops->get_residue)
		return info->ops->get_residue(channel);

	return 0;
}
EXPORT_SYMBOL(get_dma_residue);

static int search_cap(const char **haystack, const char *needle)
{
	const char **p;

	for (p = haystack; *p; p++)
		if (strcmp(*p, needle) == 0)
			return 1;

	return 0;
}

/**
 * request_dma_bycap - Allocate a DMA channel based on its capabilities
 * @dmac: List of DMA controllers to search
 * @caps: List of capabilities
 *
 * Search all channels of all DMA controllers to find a channel which
 * matches the requested capabilities. The result is the channel
 * number if a match is found, or %-ENODEV if no match is found.
 *
 * Note that not all DMA controllers export capabilities, in which
 * case they can never be allocated using this API, and so
 * request_dma() must be used specifying the channel number.
 */
int request_dma_bycap(const char **dmac, const char **caps, const char *dev_id)
{
	unsigned int found = 0;
	struct dma_info *info;
	const char **p;
	int i;

	BUG_ON(!dmac || !caps);

	list_for_each_entry(info, &registered_dmac_list, list)
		if (strcmp(*dmac, info->name) == 0) {
			found = 1;
			break;
		}

	if (!found)
		return -ENODEV;

	for (i = 0; i < info->nr_channels; i++) {
		struct dma_channel *channel = &info->channels[i];

		if (unlikely(!channel->caps))
			continue;

		for (p = caps; *p; p++) {
			if (!search_cap(channel->caps, *p))
				break;
			if (request_dma(channel->chan, dev_id) == 0)
				return channel->chan;
		}
	}

	return -EINVAL;
}
EXPORT_SYMBOL(request_dma_bycap);

int dmac_search_free_channel(const char *dev_id)
{
	struct dma_channel *channel = { 0 };
	struct dma_info *info = get_dma_info(0);
	int i;

	for (i = 0; i < info->nr_channels; i++) {
		channel = &info->channels[i];
		if (unlikely(!channel))
			return -ENODEV;

		if (atomic_read(&channel->busy) == 0)
			break;
	}

	if (info->ops->request) {
		int result = info->ops->request(channel);
		if (result)
			return result;

		atomic_set(&channel->busy, 1);
		return channel->chan;
	}

	return -ENOSYS;
}

int request_dma(unsigned int chan, const char *dev_id)
{
	struct dma_channel *channel = { 0 };
	struct dma_info *info = get_dma_info(chan);
	int result;

	channel = get_dma_channel(chan);
	if (atomic_xchg(&channel->busy, 1))
		return -EBUSY;

	strlcpy(channel->dev_id, dev_id, sizeof(channel->dev_id));

	if (info->ops->request) {
		result = info->ops->request(channel);
		if (result)
			atomic_set(&channel->busy, 0);

		return result;
	}

	return 0;
}
EXPORT_SYMBOL(request_dma);

void free_dma(unsigned int chan)
{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel = get_dma_channel(chan);

	if (info->ops->free)
		info->ops->free(channel);

	atomic_set(&channel->busy, 0);
}
EXPORT_SYMBOL(free_dma);

void dma_wait_for_completion(unsigned int chan)
{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel = get_dma_channel(chan);

	if (channel->flags & DMA_TEI_CAPABLE) {
		wait_event(channel->wait_queue,
			   (info->ops->get_residue(channel) == 0));
		return;
	}

	while (info->ops->get_residue(channel))
		cpu_relax();
}
EXPORT_SYMBOL(dma_wait_for_completion);

int register_chan_caps(const char *dmac, struct dma_chan_caps *caps)
{
	struct dma_info *info;
	unsigned int found = 0;
	int i;

	list_for_each_entry(info, &registered_dmac_list, list)
		if (strcmp(dmac, info->name) == 0) {
			found = 1;
			break;
		}

	if (unlikely(!found))
		return -ENODEV;

	for (i = 0; i < info->nr_channels; i++, caps++) {
		struct dma_channel *channel;

		if ((info->first_channel_nr + i) != caps->ch_num)
			return -EINVAL;

		channel = &info->channels[i];
		channel->caps = caps->caplist;
	}

	return 0;
}
EXPORT_SYMBOL(register_chan_caps);

void dma_configure_channel(unsigned int chan, unsigned long flags)
{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel = get_dma_channel(chan);

	if (info->ops->configure)
		info->ops->configure(channel, flags);
}
EXPORT_SYMBOL(dma_configure_channel);

int dma_xfer(unsigned int chan, unsigned long from,
	     unsigned long to, size_t size, unsigned int mode)
{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel = get_dma_channel(chan);

	channel->sar	= from;
	channel->dar	= to;
	channel->count	= size;
	channel->mode	= mode;

	return info->ops->xfer(channel);
}
EXPORT_SYMBOL(dma_xfer);

int dma_extend(unsigned int chan, unsigned long op, void *param)
{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel = get_dma_channel(chan);

	if (info->ops->extend)
		return info->ops->extend(channel, op, param);

	return -ENOSYS;
}
EXPORT_SYMBOL(dma_extend);

static int dma_read_proc(char *buf, char **start, off_t off,
			 int len, int *eof, void *data)
{
	struct dma_info *info;
	char *p = buf;

	if (list_empty(&registered_dmac_list))
		return 0;

	/*
	 * Iterate over each registered DMAC
	 */
	list_for_each_entry(info, &registered_dmac_list, list) {
		int i;

		/*
		 * Iterate over each channel
		 */
		for (i = 0; i < info->nr_channels; i++) {
			struct dma_channel *channel = info->channels + i;

			if (!(channel->flags & DMA_CONFIGURED))
				continue;

			p += sprintf(p, "%2d: %14s    %s\n", i,
				     info->name, channel->dev_id);
		}
	}

	return p - buf;
}

int register_dmac(struct dma_info *info)
{
	unsigned int total_channels, i;

	INIT_LIST_HEAD(&info->list);

	printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n",
	       info->name, info->nr_channels, info->nr_channels > 1 ? "s" : "");

	BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels);

	info->pdev = platform_device_register_simple(info->name, -1,
						     NULL, 0);
	if (IS_ERR(info->pdev))
		return PTR_ERR(info->pdev);

	/*
	 * Don't touch pre-configured channels
	 */
	if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) {
		unsigned int size;

		size = sizeof(struct dma_channel) * info->nr_channels;

		info->channels = kzalloc(size, GFP_KERNEL);
		if (!info->channels)
			return -ENOMEM;
	}

	total_channels = get_nr_channels();
	info->first_vchannel_nr = total_channels;
	for (i = 0; i < info->nr_channels; i++) {
		struct dma_channel *chan = &info->channels[i];

		atomic_set(&chan->busy, 0);

		chan->chan  = info->first_channel_nr + i;
		chan->vchan = info->first_channel_nr + i + total_channels;

		memcpy(chan->dev_id, "Unused", 7);

		if (info->flags & DMAC_CHANNELS_TEI_CAPABLE)
			chan->flags |= DMA_TEI_CAPABLE;

		init_waitqueue_head(&chan->wait_queue);
		dma_create_sysfs_files(chan, info);
	}

	list_add(&info->list, &registered_dmac_list);

	return 0;
}
EXPORT_SYMBOL(register_dmac);

void unregister_dmac(struct dma_info *info)
{
	unsigned int i;

	for (i = 0; i < info->nr_channels; i++)
		dma_remove_sysfs_files(info->channels + i, info);

	if (!(info->flags & DMAC_CHANNELS_CONFIGURED))
		kfree(info->channels);

	list_del(&info->list);
	platform_device_unregister(info->pdev);
}
EXPORT_SYMBOL(unregister_dmac);

static int __init dma_api_init(void)
{
	printk(KERN_NOTICE "DMA: Registering DMA API.\n");
	return create_proc_read_entry("dma", 0, 0, dma_read_proc, 0)
		    ? 0 : -ENOMEM;
}
subsys_initcall(dma_api_init);

MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
MODULE_DESCRIPTION("DMA API for SuperH");
MODULE_LICENSE("GPL");