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
22DEFINE_SPINLOCK(dma_spin_lock);
23static LIST_HEAD(registered_dmac_list);
24
25struct 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_channel_nr) ||
35		    (chan >= info->first_channel_nr + info->nr_channels))
36			continue;
37
38		return info;
39	}
40
41	return NULL;
42}
43EXPORT_SYMBOL(get_dma_info);
44
45struct 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}
58EXPORT_SYMBOL(get_dma_info_by_name);
59
60static 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
74struct 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->chan == chan)
86			return channel;
87	}
88
89	return NULL;
90}
91EXPORT_SYMBOL(get_dma_channel);
92
93int 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}
103EXPORT_SYMBOL(get_dma_residue);
104
105static 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 */
129int 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}
163EXPORT_SYMBOL(request_dma_bycap);
164
165int 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
192int 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}
214EXPORT_SYMBOL(request_dma);
215
216void 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}
226EXPORT_SYMBOL(free_dma);
227
228void 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}
242EXPORT_SYMBOL(dma_wait_for_completion);
243
244int 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}
271EXPORT_SYMBOL(register_chan_caps);
272
273void 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}
281EXPORT_SYMBOL(dma_configure_channel);
282
283int 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}
296EXPORT_SYMBOL(dma_xfer);
297
298int 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}
308EXPORT_SYMBOL(dma_extend);
309
310static 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
342int 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	for (i = 0; i < info->nr_channels; i++) {
373		struct dma_channel *chan = &info->channels[i];
374
375		atomic_set(&chan->busy, 0);
376
377		chan->chan  = info->first_channel_nr + i;
378		chan->vchan = info->first_channel_nr + i + total_channels;
379
380		memcpy(chan->dev_id, "Unused", 7);
381
382		if (info->flags & DMAC_CHANNELS_TEI_CAPABLE)
383			chan->flags |= DMA_TEI_CAPABLE;
384
385		init_waitqueue_head(&chan->wait_queue);
386		dma_create_sysfs_files(chan, info);
387	}
388
389	list_add(&info->list, &registered_dmac_list);
390
391	return 0;
392}
393EXPORT_SYMBOL(register_dmac);
394
395void unregister_dmac(struct dma_info *info)
396{
397	unsigned int i;
398
399	for (i = 0; i < info->nr_channels; i++)
400		dma_remove_sysfs_files(info->channels + i, info);
401
402	if (!(info->flags & DMAC_CHANNELS_CONFIGURED))
403		kfree(info->channels);
404
405	list_del(&info->list);
406	platform_device_unregister(info->pdev);
407}
408EXPORT_SYMBOL(unregister_dmac);
409
410static int __init dma_api_init(void)
411{
412	printk(KERN_NOTICE "DMA: Registering DMA API.\n");
413	create_proc_read_entry("dma", 0, 0, dma_read_proc, 0);
414	return 0;
415}
416subsys_initcall(dma_api_init);
417
418MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
419MODULE_DESCRIPTION("DMA API for SuperH");
420MODULE_LICENSE("GPL");
421