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 <linux/slab.h>
 21#include <asm/dma.h>
 22
 23DEFINE_SPINLOCK(dma_spin_lock);
 24static LIST_HEAD(registered_dmac_list);
 25
 26struct dma_info *get_dma_info(unsigned int chan)
 27{
 28	struct dma_info *info;
 29
 30	/*
 31	 * Look for each DMAC's range to determine who the owner of
 32	 * the channel is.
 33	 */
 34	list_for_each_entry(info, &registered_dmac_list, list) {
 35		if ((chan <  info->first_vchannel_nr) ||
 36		    (chan >= info->first_vchannel_nr + info->nr_channels))
 37			continue;
 38
 39		return info;
 40	}
 41
 42	return NULL;
 43}
 44EXPORT_SYMBOL(get_dma_info);
 45
 46struct dma_info *get_dma_info_by_name(const char *dmac_name)
 47{
 48	struct dma_info *info;
 49
 50	list_for_each_entry(info, &registered_dmac_list, list) {
 51		if (dmac_name && (strcmp(dmac_name, info->name) != 0))
 52			continue;
 53		else
 54			return info;
 55	}
 56
 57	return NULL;
 58}
 59EXPORT_SYMBOL(get_dma_info_by_name);
 60
 61static unsigned int get_nr_channels(void)
 62{
 63	struct dma_info *info;
 64	unsigned int nr = 0;
 65
 66	if (unlikely(list_empty(&registered_dmac_list)))
 67		return nr;
 68
 69	list_for_each_entry(info, &registered_dmac_list, list)
 70		nr += info->nr_channels;
 71
 72	return nr;
 73}
 74
 75struct dma_channel *get_dma_channel(unsigned int chan)
 76{
 77	struct dma_info *info = get_dma_info(chan);
 78	struct dma_channel *channel;
 79	int i;
 80
 81	if (unlikely(!info))
 82		return ERR_PTR(-EINVAL);
 83
 84	for (i = 0; i < info->nr_channels; i++) {
 85		channel = &info->channels[i];
 86		if (channel->vchan == chan)
 87			return channel;
 88	}
 89
 90	return NULL;
 91}
 92EXPORT_SYMBOL(get_dma_channel);
 93
 94int get_dma_residue(unsigned int chan)
 95{
 96	struct dma_info *info = get_dma_info(chan);
 97	struct dma_channel *channel = get_dma_channel(chan);
 98
 99	if (info->ops->get_residue)
100		return info->ops->get_residue(channel);
101
102	return 0;
103}
104EXPORT_SYMBOL(get_dma_residue);
105
106static int search_cap(const char **haystack, const char *needle)
107{
108	const char **p;
109
110	for (p = haystack; *p; p++)
111		if (strcmp(*p, needle) == 0)
112			return 1;
113
114	return 0;
115}
116
117/**
118 * request_dma_bycap - Allocate a DMA channel based on its capabilities
119 * @dmac: List of DMA controllers to search
120 * @caps: List of capabilities
121 *
122 * Search all channels of all DMA controllers to find a channel which
123 * matches the requested capabilities. The result is the channel
124 * number if a match is found, or %-ENODEV if no match is found.
125 *
126 * Note that not all DMA controllers export capabilities, in which
127 * case they can never be allocated using this API, and so
128 * request_dma() must be used specifying the channel number.
129 */
130int request_dma_bycap(const char **dmac, const char **caps, const char *dev_id)
131{
132	unsigned int found = 0;
133	struct dma_info *info;
134	const char **p;
135	int i;
136
137	BUG_ON(!dmac || !caps);
138
139	list_for_each_entry(info, &registered_dmac_list, list)
140		if (strcmp(*dmac, info->name) == 0) {
141			found = 1;
142			break;
143		}
144
145	if (!found)
146		return -ENODEV;
147
148	for (i = 0; i < info->nr_channels; i++) {
149		struct dma_channel *channel = &info->channels[i];
150
151		if (unlikely(!channel->caps))
152			continue;
153
154		for (p = caps; *p; p++) {
155			if (!search_cap(channel->caps, *p))
156				break;
157			if (request_dma(channel->chan, dev_id) == 0)
158				return channel->chan;
159		}
160	}
161
162	return -EINVAL;
163}
164EXPORT_SYMBOL(request_dma_bycap);
165
166int dmac_search_free_channel(const char *dev_id)
167{
168	struct dma_channel *channel = { 0 };
169	struct dma_info *info = get_dma_info(0);
170	int i;
171
172	for (i = 0; i < info->nr_channels; i++) {
173		channel = &info->channels[i];
174		if (unlikely(!channel))
175			return -ENODEV;
176
177		if (atomic_read(&channel->busy) == 0)
178			break;
179	}
180
181	if (info->ops->request) {
182		int result = info->ops->request(channel);
183		if (result)
184			return result;
185
186		atomic_set(&channel->busy, 1);
187		return channel->chan;
188	}
189
190	return -ENOSYS;
191}
192
193int request_dma(unsigned int chan, const char *dev_id)
194{
195	struct dma_channel *channel = { 0 };
196	struct dma_info *info = get_dma_info(chan);
197	int result;
198
199	channel = get_dma_channel(chan);
200	if (atomic_xchg(&channel->busy, 1))
201		return -EBUSY;
202
203	strlcpy(channel->dev_id, dev_id, sizeof(channel->dev_id));
204
205	if (info->ops->request) {
206		result = info->ops->request(channel);
207		if (result)
208			atomic_set(&channel->busy, 0);
209
210		return result;
211	}
212
213	return 0;
214}
215EXPORT_SYMBOL(request_dma);
216
217void free_dma(unsigned int chan)
218{
219	struct dma_info *info = get_dma_info(chan);
220	struct dma_channel *channel = get_dma_channel(chan);
221
222	if (info->ops->free)
223		info->ops->free(channel);
224
225	atomic_set(&channel->busy, 0);
226}
227EXPORT_SYMBOL(free_dma);
228
229void dma_wait_for_completion(unsigned int chan)
230{
231	struct dma_info *info = get_dma_info(chan);
232	struct dma_channel *channel = get_dma_channel(chan);
233
234	if (channel->flags & DMA_TEI_CAPABLE) {
235		wait_event(channel->wait_queue,
236			   (info->ops->get_residue(channel) == 0));
237		return;
238	}
239
240	while (info->ops->get_residue(channel))
241		cpu_relax();
242}
243EXPORT_SYMBOL(dma_wait_for_completion);
244
245int register_chan_caps(const char *dmac, struct dma_chan_caps *caps)
246{
247	struct dma_info *info;
248	unsigned int found = 0;
249	int i;
250
251	list_for_each_entry(info, &registered_dmac_list, list)
252		if (strcmp(dmac, info->name) == 0) {
253			found = 1;
254			break;
255		}
256
257	if (unlikely(!found))
258		return -ENODEV;
259
260	for (i = 0; i < info->nr_channels; i++, caps++) {
261		struct dma_channel *channel;
262
263		if ((info->first_channel_nr + i) != caps->ch_num)
264			return -EINVAL;
265
266		channel = &info->channels[i];
267		channel->caps = caps->caplist;
268	}
269
270	return 0;
271}
272EXPORT_SYMBOL(register_chan_caps);
273
274void dma_configure_channel(unsigned int chan, unsigned long flags)
275{
276	struct dma_info *info = get_dma_info(chan);
277	struct dma_channel *channel = get_dma_channel(chan);
278
279	if (info->ops->configure)
280		info->ops->configure(channel, flags);
281}
282EXPORT_SYMBOL(dma_configure_channel);
283
284int dma_xfer(unsigned int chan, unsigned long from,
285	     unsigned long to, size_t size, unsigned int mode)
286{
287	struct dma_info *info = get_dma_info(chan);
288	struct dma_channel *channel = get_dma_channel(chan);
289
290	channel->sar	= from;
291	channel->dar	= to;
292	channel->count	= size;
293	channel->mode	= mode;
294
295	return info->ops->xfer(channel);
296}
297EXPORT_SYMBOL(dma_xfer);
298
299int dma_extend(unsigned int chan, unsigned long op, void *param)
300{
301	struct dma_info *info = get_dma_info(chan);
302	struct dma_channel *channel = get_dma_channel(chan);
303
304	if (info->ops->extend)
305		return info->ops->extend(channel, op, param);
306
307	return -ENOSYS;
308}
309EXPORT_SYMBOL(dma_extend);
310
311static int dma_read_proc(char *buf, char **start, off_t off,
312			 int len, int *eof, void *data)
313{
314	struct dma_info *info;
315	char *p = buf;
316
317	if (list_empty(&registered_dmac_list))
318		return 0;
319
320	/*
321	 * Iterate over each registered DMAC
322	 */
323	list_for_each_entry(info, &registered_dmac_list, list) {
324		int i;
325
326		/*
327		 * Iterate over each channel
328		 */
329		for (i = 0; i < info->nr_channels; i++) {
330			struct dma_channel *channel = info->channels + i;
331
332			if (!(channel->flags & DMA_CONFIGURED))
333				continue;
334
335			p += sprintf(p, "%2d: %14s    %s\n", i,
336				     info->name, channel->dev_id);
337		}
338	}
339
340	return p - buf;
341}
342
343int register_dmac(struct dma_info *info)
344{
345	unsigned int total_channels, i;
346
347	INIT_LIST_HEAD(&info->list);
348
349	printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n",
350	       info->name, info->nr_channels, info->nr_channels > 1 ? "s" : "");
351
352	BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels);
353
354	info->pdev = platform_device_register_simple(info->name, -1,
355						     NULL, 0);
356	if (IS_ERR(info->pdev))
357		return PTR_ERR(info->pdev);
358
359	/*
360	 * Don't touch pre-configured channels
361	 */
362	if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) {
363		unsigned int size;
364
365		size = sizeof(struct dma_channel) * info->nr_channels;
366
367		info->channels = kzalloc(size, GFP_KERNEL);
368		if (!info->channels)
369			return -ENOMEM;
370	}
371
372	total_channels = get_nr_channels();
373	info->first_vchannel_nr = total_channels;
374	for (i = 0; i < info->nr_channels; i++) {
375		struct dma_channel *chan = &info->channels[i];
376
377		atomic_set(&chan->busy, 0);
378
379		chan->chan  = info->first_channel_nr + i;
380		chan->vchan = info->first_channel_nr + i + total_channels;
381
382		memcpy(chan->dev_id, "Unused", 7);
383
384		if (info->flags & DMAC_CHANNELS_TEI_CAPABLE)
385			chan->flags |= DMA_TEI_CAPABLE;
386
387		init_waitqueue_head(&chan->wait_queue);
388		dma_create_sysfs_files(chan, info);
389	}
390
391	list_add(&info->list, &registered_dmac_list);
392
393	return 0;
394}
395EXPORT_SYMBOL(register_dmac);
396
397void unregister_dmac(struct dma_info *info)
398{
399	unsigned int i;
400
401	for (i = 0; i < info->nr_channels; i++)
402		dma_remove_sysfs_files(info->channels + i, info);
403
404	if (!(info->flags & DMAC_CHANNELS_CONFIGURED))
405		kfree(info->channels);
406
407	list_del(&info->list);
408	platform_device_unregister(info->pdev);
409}
410EXPORT_SYMBOL(unregister_dmac);
411
412static int __init dma_api_init(void)
413{
414	printk(KERN_NOTICE "DMA: Registering DMA API.\n");
415	return create_proc_read_entry("dma", 0, 0, dma_read_proc, 0)
416		    ? 0 : -ENOMEM;
417}
418subsys_initcall(dma_api_init);
419
420MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
421MODULE_DESCRIPTION("DMA API for SuperH");
422MODULE_LICENSE("GPL");