1// SPDX-License-Identifier: GPL-2.0
2/*
3 * arch/sh/drivers/dma/dma-api.c
4 *
5 * SuperH-specific DMA management API
6 *
7 * Copyright (C) 2003, 2004, 2005  Paul Mundt
8 */
9#include <linux/init.h>
10#include <linux/module.h>
11#include <linux/spinlock.h>
12#include <linux/proc_fs.h>
13#include <linux/seq_file.h>
14#include <linux/list.h>
15#include <linux/platform_device.h>
16#include <linux/mm.h>
17#include <linux/sched.h>
18#include <linux/slab.h>
19#include <asm/dma.h>
20
21DEFINE_SPINLOCK(dma_spin_lock);
22static LIST_HEAD(registered_dmac_list);
23
24struct dma_info *get_dma_info(unsigned int chan)
25{
26	struct dma_info *info;
27
28	/*
29	 * Look for each DMAC's range to determine who the owner of
30	 * the channel is.
31	 */
32	list_for_each_entry(info, &registered_dmac_list, list) {
33		if ((chan <  info->first_vchannel_nr) ||
34		    (chan >= info->first_vchannel_nr + info->nr_channels))
35			continue;
36
37		return info;
38	}
39
40	return NULL;
41}
42EXPORT_SYMBOL(get_dma_info);
43
44struct dma_info *get_dma_info_by_name(const char *dmac_name)
45{
46	struct dma_info *info;
47
48	list_for_each_entry(info, &registered_dmac_list, list) {
49		if (dmac_name && (strcmp(dmac_name, info->name) != 0))
50			continue;
51		else
52			return info;
53	}
54
55	return NULL;
56}
57EXPORT_SYMBOL(get_dma_info_by_name);
58
59static unsigned int get_nr_channels(void)
60{
61	struct dma_info *info;
62	unsigned int nr = 0;
63
64	if (unlikely(list_empty(&registered_dmac_list)))
65		return nr;
66
67	list_for_each_entry(info, &registered_dmac_list, list)
68		nr += info->nr_channels;
69
70	return nr;
71}
72
73struct dma_channel *get_dma_channel(unsigned int chan)
74{
75	struct dma_info *info = get_dma_info(chan);
76	struct dma_channel *channel;
77	int i;
78
79	if (unlikely(!info))
80		return ERR_PTR(-EINVAL);
81
82	for (i = 0; i < info->nr_channels; i++) {
83		channel = &info->channels[i];
84		if (channel->vchan == chan)
85			return channel;
86	}
87
88	return NULL;
89}
90EXPORT_SYMBOL(get_dma_channel);
91
92int get_dma_residue(unsigned int chan)
93{
94	struct dma_info *info = get_dma_info(chan);
95	struct dma_channel *channel = get_dma_channel(chan);
96
97	if (info->ops->get_residue)
98		return info->ops->get_residue(channel);
99
100	return 0;
101}
102EXPORT_SYMBOL(get_dma_residue);
103
104static int search_cap(const char **haystack, const char *needle)
105{
106	const char **p;
107
108	for (p = haystack; *p; p++)
109		if (strcmp(*p, needle) == 0)
110			return 1;
111
112	return 0;
113}
114
115/**
116 * request_dma_bycap - Allocate a DMA channel based on its capabilities
117 * @dmac: List of DMA controllers to search
118 * @caps: List of capabilities
119 *
120 * Search all channels of all DMA controllers to find a channel which
121 * matches the requested capabilities. The result is the channel
122 * number if a match is found, or %-ENODEV if no match is found.
123 *
124 * Note that not all DMA controllers export capabilities, in which
125 * case they can never be allocated using this API, and so
126 * request_dma() must be used specifying the channel number.
127 */
128int request_dma_bycap(const char **dmac, const char **caps, const char *dev_id)
129{
130	unsigned int found = 0;
131	struct dma_info *info;
132	const char **p;
133	int i;
134
135	BUG_ON(!dmac || !caps);
136
137	list_for_each_entry(info, &registered_dmac_list, list)
138		if (strcmp(*dmac, info->name) == 0) {
139			found = 1;
140			break;
141		}
142
143	if (!found)
144		return -ENODEV;
145
146	for (i = 0; i < info->nr_channels; i++) {
147		struct dma_channel *channel = &info->channels[i];
148
149		if (unlikely(!channel->caps))
150			continue;
151
152		for (p = caps; *p; p++) {
153			if (!search_cap(channel->caps, *p))
154				break;
155			if (request_dma(channel->chan, dev_id) == 0)
156				return channel->chan;
157		}
158	}
159
160	return -EINVAL;
161}
162EXPORT_SYMBOL(request_dma_bycap);
163
164int dmac_search_free_channel(const char *dev_id)
165{
166	struct dma_channel *channel = { 0 };
167	struct dma_info *info = get_dma_info(0);
168	int i;
169
170	for (i = 0; i < info->nr_channels; i++) {
171		channel = &info->channels[i];
172		if (unlikely(!channel))
173			return -ENODEV;
174
175		if (atomic_read(&channel->busy) == 0)
176			break;
177	}
178
179	if (info->ops->request) {
180		int result = info->ops->request(channel);
181		if (result)
182			return result;
183
184		atomic_set(&channel->busy, 1);
185		return channel->chan;
186	}
187
188	return -ENOSYS;
189}
190
191int request_dma(unsigned int chan, const char *dev_id)
192{
193	struct dma_channel *channel = { 0 };
194	struct dma_info *info = get_dma_info(chan);
195	int result;
196
197	channel = get_dma_channel(chan);
198	if (atomic_xchg(&channel->busy, 1))
199		return -EBUSY;
200
201	strscpy(channel->dev_id, dev_id, sizeof(channel->dev_id));
202
203	if (info->ops->request) {
204		result = info->ops->request(channel);
205		if (result)
206			atomic_set(&channel->busy, 0);
207
208		return result;
209	}
210
211	return 0;
212}
213EXPORT_SYMBOL(request_dma);
214
215void free_dma(unsigned int chan)
216{
217	struct dma_info *info = get_dma_info(chan);
218	struct dma_channel *channel = get_dma_channel(chan);
219
220	if (info->ops->free)
221		info->ops->free(channel);
222
223	atomic_set(&channel->busy, 0);
224}
225EXPORT_SYMBOL(free_dma);
226
227void dma_wait_for_completion(unsigned int chan)
228{
229	struct dma_info *info = get_dma_info(chan);
230	struct dma_channel *channel = get_dma_channel(chan);
231
232	if (channel->flags & DMA_TEI_CAPABLE) {
233		wait_event(channel->wait_queue,
234			   (info->ops->get_residue(channel) == 0));
235		return;
236	}
237
238	while (info->ops->get_residue(channel))
239		cpu_relax();
240}
241EXPORT_SYMBOL(dma_wait_for_completion);
242
243int register_chan_caps(const char *dmac, struct dma_chan_caps *caps)
244{
245	struct dma_info *info;
246	unsigned int found = 0;
247	int i;
248
249	list_for_each_entry(info, &registered_dmac_list, list)
250		if (strcmp(dmac, info->name) == 0) {
251			found = 1;
252			break;
253		}
254
255	if (unlikely(!found))
256		return -ENODEV;
257
258	for (i = 0; i < info->nr_channels; i++, caps++) {
259		struct dma_channel *channel;
260
261		if ((info->first_channel_nr + i) != caps->ch_num)
262			return -EINVAL;
263
264		channel = &info->channels[i];
265		channel->caps = caps->caplist;
266	}
267
268	return 0;
269}
270EXPORT_SYMBOL(register_chan_caps);
271
272void dma_configure_channel(unsigned int chan, unsigned long flags)
273{
274	struct dma_info *info = get_dma_info(chan);
275	struct dma_channel *channel = get_dma_channel(chan);
276
277	if (info->ops->configure)
278		info->ops->configure(channel, flags);
279}
280EXPORT_SYMBOL(dma_configure_channel);
281
282int dma_xfer(unsigned int chan, unsigned long from,
283	     unsigned long to, size_t size, unsigned int mode)
284{
285	struct dma_info *info = get_dma_info(chan);
286	struct dma_channel *channel = get_dma_channel(chan);
287
288	channel->sar	= from;
289	channel->dar	= to;
290	channel->count	= size;
291	channel->mode	= mode;
292
293	return info->ops->xfer(channel);
294}
295EXPORT_SYMBOL(dma_xfer);
296
297int dma_extend(unsigned int chan, unsigned long op, void *param)
298{
299	struct dma_info *info = get_dma_info(chan);
300	struct dma_channel *channel = get_dma_channel(chan);
301
302	if (info->ops->extend)
303		return info->ops->extend(channel, op, param);
304
305	return -ENOSYS;
306}
307EXPORT_SYMBOL(dma_extend);
308
309static int dma_proc_show(struct seq_file *m, void *v)
310{
311	struct dma_info *info = v;
312
313	if (list_empty(&registered_dmac_list))
314		return 0;
315
316	/*
317	 * Iterate over each registered DMAC
318	 */
319	list_for_each_entry(info, &registered_dmac_list, list) {
320		int i;
321
322		/*
323		 * Iterate over each channel
324		 */
325		for (i = 0; i < info->nr_channels; i++) {
326			struct dma_channel *channel = info->channels + i;
327
328			if (!(channel->flags & DMA_CONFIGURED))
329				continue;
330
331			seq_printf(m, "%2d: %14s    %s\n", i,
332				   info->name, channel->dev_id);
333		}
334	}
335
336	return 0;
337}
338
339int register_dmac(struct dma_info *info)
340{
341	unsigned int total_channels, i;
342
343	INIT_LIST_HEAD(&info->list);
344
345	printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n",
346	       info->name, info->nr_channels, info->nr_channels > 1 ? "s" : "");
347
348	BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels);
349
350	info->pdev = platform_device_register_simple(info->name, -1,
351						     NULL, 0);
352	if (IS_ERR(info->pdev))
353		return PTR_ERR(info->pdev);
354
355	/*
356	 * Don't touch pre-configured channels
357	 */
358	if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) {
359		unsigned int size;
360
361		size = sizeof(struct dma_channel) * info->nr_channels;
362
363		info->channels = kzalloc(size, GFP_KERNEL);
364		if (!info->channels)
365			return -ENOMEM;
366	}
367
368	total_channels = get_nr_channels();
369	info->first_vchannel_nr = total_channels;
370	for (i = 0; i < info->nr_channels; i++) {
371		struct dma_channel *chan = &info->channels[i];
372
373		atomic_set(&chan->busy, 0);
374
375		chan->chan  = info->first_channel_nr + i;
376		chan->vchan = info->first_channel_nr + i + total_channels;
377
378		memcpy(chan->dev_id, "Unused", 7);
379
380		if (info->flags & DMAC_CHANNELS_TEI_CAPABLE)
381			chan->flags |= DMA_TEI_CAPABLE;
382
383		init_waitqueue_head(&chan->wait_queue);
384		dma_create_sysfs_files(chan, info);
385	}
386
387	list_add(&info->list, &registered_dmac_list);
388
389	return 0;
390}
391EXPORT_SYMBOL(register_dmac);
392
393void unregister_dmac(struct dma_info *info)
394{
395	unsigned int i;
396
397	for (i = 0; i < info->nr_channels; i++)
398		dma_remove_sysfs_files(info->channels + i, info);
399
400	if (!(info->flags & DMAC_CHANNELS_CONFIGURED))
401		kfree(info->channels);
402
403	list_del(&info->list);
404	platform_device_unregister(info->pdev);
405}
406EXPORT_SYMBOL(unregister_dmac);
407
408static int __init dma_api_init(void)
409{
410	printk(KERN_NOTICE "DMA: Registering DMA API.\n");
411	return proc_create_single("dma", 0, NULL, dma_proc_show) ? 0 : -ENOMEM;
412}
413subsys_initcall(dma_api_init);
414
415MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
416MODULE_DESCRIPTION("DMA API for SuperH");
417MODULE_LICENSE("GPL v2");
418