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 
21 DEFINE_SPINLOCK(dma_spin_lock);
22 static LIST_HEAD(registered_dmac_list);
23 
get_dma_info(unsigned int chan)24 struct 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 }
42 EXPORT_SYMBOL(get_dma_info);
43 
get_dma_info_by_name(const char * dmac_name)44 struct 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 }
57 EXPORT_SYMBOL(get_dma_info_by_name);
58 
get_nr_channels(void)59 static 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 
get_dma_channel(unsigned int chan)73 struct 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 }
90 EXPORT_SYMBOL(get_dma_channel);
91 
get_dma_residue(unsigned int chan)92 int 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 }
102 EXPORT_SYMBOL(get_dma_residue);
103 
search_cap(const char ** haystack,const char * needle)104 static 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  */
request_dma_bycap(const char ** dmac,const char ** caps,const char * dev_id)128 int 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 }
162 EXPORT_SYMBOL(request_dma_bycap);
163 
dmac_search_free_channel(const char * dev_id)164 int 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 
request_dma(unsigned int chan,const char * dev_id)191 int 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 	strlcpy(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 }
213 EXPORT_SYMBOL(request_dma);
214 
free_dma(unsigned int chan)215 void 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 }
225 EXPORT_SYMBOL(free_dma);
226 
dma_wait_for_completion(unsigned int chan)227 void 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 }
241 EXPORT_SYMBOL(dma_wait_for_completion);
242 
register_chan_caps(const char * dmac,struct dma_chan_caps * caps)243 int 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 }
270 EXPORT_SYMBOL(register_chan_caps);
271 
dma_configure_channel(unsigned int chan,unsigned long flags)272 void 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 }
280 EXPORT_SYMBOL(dma_configure_channel);
281 
dma_xfer(unsigned int chan,unsigned long from,unsigned long to,size_t size,unsigned int mode)282 int 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 }
295 EXPORT_SYMBOL(dma_xfer);
296 
dma_extend(unsigned int chan,unsigned long op,void * param)297 int 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 }
307 EXPORT_SYMBOL(dma_extend);
308 
dma_proc_show(struct seq_file * m,void * v)309 static 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 
register_dmac(struct dma_info * info)339 int 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 }
391 EXPORT_SYMBOL(register_dmac);
392 
unregister_dmac(struct dma_info * info)393 void 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 }
406 EXPORT_SYMBOL(unregister_dmac);
407 
dma_api_init(void)408 static 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 }
413 subsys_initcall(dma_api_init);
414 
415 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
416 MODULE_DESCRIPTION("DMA API for SuperH");
417 MODULE_LICENSE("GPL v2");
418