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
24DEFINE_SPINLOCK(dma_spin_lock);
25static LIST_HEAD(registered_dmac_list);
26
27struct 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}
45EXPORT_SYMBOL(get_dma_info);
46
47struct 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}
60EXPORT_SYMBOL(get_dma_info_by_name);
61
62static 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
76struct 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}
93EXPORT_SYMBOL(get_dma_channel);
94
95int 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}
105EXPORT_SYMBOL(get_dma_residue);
106
107static 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 */
131int 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}
165EXPORT_SYMBOL(request_dma_bycap);
166
167int 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
194int 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}
216EXPORT_SYMBOL(request_dma);
217
218void 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}
228EXPORT_SYMBOL(free_dma);
229
230void 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}
244EXPORT_SYMBOL(dma_wait_for_completion);
245
246int 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}
273EXPORT_SYMBOL(register_chan_caps);
274
275void 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}
283EXPORT_SYMBOL(dma_configure_channel);
284
285int 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}
298EXPORT_SYMBOL(dma_xfer);
299
300int 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}
310EXPORT_SYMBOL(dma_extend);
311
312static 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
342static int dma_proc_open(struct inode *inode, struct file *file)
343{
344	return single_open(file, dma_proc_show, NULL);
345}
346
347static 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
354int 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}
406EXPORT_SYMBOL(register_dmac);
407
408void 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}
421EXPORT_SYMBOL(unregister_dmac);
422
423static 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}
428subsys_initcall(dma_api_init);
429
430MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
431MODULE_DESCRIPTION("DMA API for SuperH");
432MODULE_LICENSE("GPL");
433