1 /*
2  *  Digital Audio (PCM) abstract layer
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4  *
5  *
6  *   This program is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU General Public License as published by
8  *   the Free Software Foundation; either version 2 of the License, or
9  *   (at your option) any later version.
10  *
11  *   This program is distributed in the hope that it will be useful,
12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *   GNU General Public License for more details.
15  *
16  *   You should have received a copy of the GNU General Public License
17  *   along with this program; if not, write to the Free Software
18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19  *
20  */
21 
22 #include <asm/io.h>
23 #include <linux/time.h>
24 #include <linux/init.h>
25 #include <linux/slab.h>
26 #include <linux/moduleparam.h>
27 #include <linux/vmalloc.h>
28 #include <linux/export.h>
29 #include <sound/core.h>
30 #include <sound/pcm.h>
31 #include <sound/info.h>
32 #include <sound/initval.h>
33 
34 static int preallocate_dma = 1;
35 module_param(preallocate_dma, int, 0444);
36 MODULE_PARM_DESC(preallocate_dma, "Preallocate DMA memory when the PCM devices are initialized.");
37 
38 static int maximum_substreams = 4;
39 module_param(maximum_substreams, int, 0444);
40 MODULE_PARM_DESC(maximum_substreams, "Maximum substreams with preallocated DMA memory.");
41 
42 static const size_t snd_minimum_buffer = 16384;
43 
44 
45 /*
46  * try to allocate as the large pages as possible.
47  * stores the resultant memory size in *res_size.
48  *
49  * the minimum size is snd_minimum_buffer.  it should be power of 2.
50  */
preallocate_pcm_pages(struct snd_pcm_substream * substream,size_t size)51 static int preallocate_pcm_pages(struct snd_pcm_substream *substream, size_t size)
52 {
53 	struct snd_dma_buffer *dmab = &substream->dma_buffer;
54 	int err;
55 
56 	/* already reserved? */
57 	if (snd_dma_get_reserved_buf(dmab, substream->dma_buf_id) > 0) {
58 		if (dmab->bytes >= size)
59 			return 0; /* yes */
60 		/* no, free the reserved block */
61 		snd_dma_free_pages(dmab);
62 		dmab->bytes = 0;
63 	}
64 
65 	do {
66 		if ((err = snd_dma_alloc_pages(dmab->dev.type, dmab->dev.dev,
67 					       size, dmab)) < 0) {
68 			if (err != -ENOMEM)
69 				return err; /* fatal error */
70 		} else
71 			return 0;
72 		size >>= 1;
73 	} while (size >= snd_minimum_buffer);
74 	dmab->bytes = 0; /* tell error */
75 	return 0;
76 }
77 
78 /*
79  * release the preallocated buffer if not yet done.
80  */
snd_pcm_lib_preallocate_dma_free(struct snd_pcm_substream * substream)81 static void snd_pcm_lib_preallocate_dma_free(struct snd_pcm_substream *substream)
82 {
83 	if (substream->dma_buffer.area == NULL)
84 		return;
85 	if (substream->dma_buf_id)
86 		snd_dma_reserve_buf(&substream->dma_buffer, substream->dma_buf_id);
87 	else
88 		snd_dma_free_pages(&substream->dma_buffer);
89 	substream->dma_buffer.area = NULL;
90 }
91 
92 /**
93  * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
94  * @substream: the pcm substream instance
95  *
96  * Releases the pre-allocated buffer of the given substream.
97  *
98  * Returns zero if successful, or a negative error code on failure.
99  */
snd_pcm_lib_preallocate_free(struct snd_pcm_substream * substream)100 int snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
101 {
102 	snd_pcm_lib_preallocate_dma_free(substream);
103 #ifdef CONFIG_SND_VERBOSE_PROCFS
104 	snd_info_free_entry(substream->proc_prealloc_max_entry);
105 	substream->proc_prealloc_max_entry = NULL;
106 	snd_info_free_entry(substream->proc_prealloc_entry);
107 	substream->proc_prealloc_entry = NULL;
108 #endif
109 	return 0;
110 }
111 
112 /**
113  * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
114  * @pcm: the pcm instance
115  *
116  * Releases all the pre-allocated buffers on the given pcm.
117  *
118  * Returns zero if successful, or a negative error code on failure.
119  */
snd_pcm_lib_preallocate_free_for_all(struct snd_pcm * pcm)120 int snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
121 {
122 	struct snd_pcm_substream *substream;
123 	int stream;
124 
125 	for (stream = 0; stream < 2; stream++)
126 		for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
127 			snd_pcm_lib_preallocate_free(substream);
128 	return 0;
129 }
130 
131 EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
132 
133 #ifdef CONFIG_SND_VERBOSE_PROCFS
134 /*
135  * read callback for prealloc proc file
136  *
137  * prints the current allocated size in kB.
138  */
snd_pcm_lib_preallocate_proc_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)139 static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
140 					      struct snd_info_buffer *buffer)
141 {
142 	struct snd_pcm_substream *substream = entry->private_data;
143 	snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
144 }
145 
146 /*
147  * read callback for prealloc_max proc file
148  *
149  * prints the maximum allowed size in kB.
150  */
snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)151 static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
152 						  struct snd_info_buffer *buffer)
153 {
154 	struct snd_pcm_substream *substream = entry->private_data;
155 	snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
156 }
157 
158 /*
159  * write callback for prealloc proc file
160  *
161  * accepts the preallocation size in kB.
162  */
snd_pcm_lib_preallocate_proc_write(struct snd_info_entry * entry,struct snd_info_buffer * buffer)163 static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
164 					       struct snd_info_buffer *buffer)
165 {
166 	struct snd_pcm_substream *substream = entry->private_data;
167 	char line[64], str[64];
168 	size_t size;
169 	struct snd_dma_buffer new_dmab;
170 
171 	if (substream->runtime) {
172 		buffer->error = -EBUSY;
173 		return;
174 	}
175 	if (!snd_info_get_line(buffer, line, sizeof(line))) {
176 		snd_info_get_str(str, line, sizeof(str));
177 		size = simple_strtoul(str, NULL, 10) * 1024;
178 		if ((size != 0 && size < 8192) || size > substream->dma_max) {
179 			buffer->error = -EINVAL;
180 			return;
181 		}
182 		if (substream->dma_buffer.bytes == size)
183 			return;
184 		memset(&new_dmab, 0, sizeof(new_dmab));
185 		new_dmab.dev = substream->dma_buffer.dev;
186 		if (size > 0) {
187 			if (snd_dma_alloc_pages(substream->dma_buffer.dev.type,
188 						substream->dma_buffer.dev.dev,
189 						size, &new_dmab) < 0) {
190 				buffer->error = -ENOMEM;
191 				return;
192 			}
193 			substream->buffer_bytes_max = size;
194 		} else {
195 			substream->buffer_bytes_max = UINT_MAX;
196 		}
197 		if (substream->dma_buffer.area)
198 			snd_dma_free_pages(&substream->dma_buffer);
199 		substream->dma_buffer = new_dmab;
200 	} else {
201 		buffer->error = -EINVAL;
202 	}
203 }
204 
preallocate_info_init(struct snd_pcm_substream * substream)205 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
206 {
207 	struct snd_info_entry *entry;
208 
209 	if ((entry = snd_info_create_card_entry(substream->pcm->card, "prealloc", substream->proc_root)) != NULL) {
210 		entry->c.text.read = snd_pcm_lib_preallocate_proc_read;
211 		entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
212 		entry->mode |= S_IWUSR;
213 		entry->private_data = substream;
214 		if (snd_info_register(entry) < 0) {
215 			snd_info_free_entry(entry);
216 			entry = NULL;
217 		}
218 	}
219 	substream->proc_prealloc_entry = entry;
220 	if ((entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max", substream->proc_root)) != NULL) {
221 		entry->c.text.read = snd_pcm_lib_preallocate_max_proc_read;
222 		entry->private_data = substream;
223 		if (snd_info_register(entry) < 0) {
224 			snd_info_free_entry(entry);
225 			entry = NULL;
226 		}
227 	}
228 	substream->proc_prealloc_max_entry = entry;
229 }
230 
231 #else /* !CONFIG_SND_VERBOSE_PROCFS */
232 #define preallocate_info_init(s)
233 #endif /* CONFIG_SND_VERBOSE_PROCFS */
234 
235 /*
236  * pre-allocate the buffer and create a proc file for the substream
237  */
snd_pcm_lib_preallocate_pages1(struct snd_pcm_substream * substream,size_t size,size_t max)238 static int snd_pcm_lib_preallocate_pages1(struct snd_pcm_substream *substream,
239 					  size_t size, size_t max)
240 {
241 
242 	if (size > 0 && preallocate_dma && substream->number < maximum_substreams)
243 		preallocate_pcm_pages(substream, size);
244 
245 	if (substream->dma_buffer.bytes > 0)
246 		substream->buffer_bytes_max = substream->dma_buffer.bytes;
247 	substream->dma_max = max;
248 	preallocate_info_init(substream);
249 	return 0;
250 }
251 
252 
253 /**
254  * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
255  * @substream: the pcm substream instance
256  * @type: DMA type (SNDRV_DMA_TYPE_*)
257  * @data: DMA type dependent data
258  * @size: the requested pre-allocation size in bytes
259  * @max: the max. allowed pre-allocation size
260  *
261  * Do pre-allocation for the given DMA buffer type.
262  *
263  * When substream->dma_buf_id is set, the function tries to look for
264  * the reserved buffer, and the buffer is not freed but reserved at
265  * destruction time.  The dma_buf_id must be unique for all systems
266  * (in the same DMA buffer type) e.g. using snd_dma_pci_buf_id().
267  *
268  * Returns zero if successful, or a negative error code on failure.
269  */
snd_pcm_lib_preallocate_pages(struct snd_pcm_substream * substream,int type,struct device * data,size_t size,size_t max)270 int snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
271 				  int type, struct device *data,
272 				  size_t size, size_t max)
273 {
274 	substream->dma_buffer.dev.type = type;
275 	substream->dma_buffer.dev.dev = data;
276 	return snd_pcm_lib_preallocate_pages1(substream, size, max);
277 }
278 
279 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
280 
281 /**
282  * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
283  * @pcm: the pcm instance
284  * @type: DMA type (SNDRV_DMA_TYPE_*)
285  * @data: DMA type dependent data
286  * @size: the requested pre-allocation size in bytes
287  * @max: the max. allowed pre-allocation size
288  *
289  * Do pre-allocation to all substreams of the given pcm for the
290  * specified DMA type.
291  *
292  * Returns zero if successful, or a negative error code on failure.
293  */
snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm * pcm,int type,void * data,size_t size,size_t max)294 int snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
295 					  int type, void *data,
296 					  size_t size, size_t max)
297 {
298 	struct snd_pcm_substream *substream;
299 	int stream, err;
300 
301 	for (stream = 0; stream < 2; stream++)
302 		for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
303 			if ((err = snd_pcm_lib_preallocate_pages(substream, type, data, size, max)) < 0)
304 				return err;
305 	return 0;
306 }
307 
308 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
309 
310 #ifdef CONFIG_SND_DMA_SGBUF
311 /**
312  * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
313  * @substream: the pcm substream instance
314  * @offset: the buffer offset
315  *
316  * Returns the page struct at the given buffer offset.
317  * Used as the page callback of PCM ops.
318  */
snd_pcm_sgbuf_ops_page(struct snd_pcm_substream * substream,unsigned long offset)319 struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
320 {
321 	struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
322 
323 	unsigned int idx = offset >> PAGE_SHIFT;
324 	if (idx >= (unsigned int)sgbuf->pages)
325 		return NULL;
326 	return sgbuf->page_table[idx];
327 }
328 
329 EXPORT_SYMBOL(snd_pcm_sgbuf_ops_page);
330 
331 /*
332  * compute the max chunk size with continuous pages on sg-buffer
333  */
snd_pcm_sgbuf_get_chunk_size(struct snd_pcm_substream * substream,unsigned int ofs,unsigned int size)334 unsigned int snd_pcm_sgbuf_get_chunk_size(struct snd_pcm_substream *substream,
335 					  unsigned int ofs, unsigned int size)
336 {
337 	struct snd_sg_buf *sg = snd_pcm_substream_sgbuf(substream);
338 	unsigned int start, end, pg;
339 
340 	start = ofs >> PAGE_SHIFT;
341 	end = (ofs + size - 1) >> PAGE_SHIFT;
342 	/* check page continuity */
343 	pg = sg->table[start].addr >> PAGE_SHIFT;
344 	for (;;) {
345 		start++;
346 		if (start > end)
347 			break;
348 		pg++;
349 		if ((sg->table[start].addr >> PAGE_SHIFT) != pg)
350 			return (start << PAGE_SHIFT) - ofs;
351 	}
352 	/* ok, all on continuous pages */
353 	return size;
354 }
355 EXPORT_SYMBOL(snd_pcm_sgbuf_get_chunk_size);
356 #endif /* CONFIG_SND_DMA_SGBUF */
357 
358 /**
359  * snd_pcm_lib_malloc_pages - allocate the DMA buffer
360  * @substream: the substream to allocate the DMA buffer to
361  * @size: the requested buffer size in bytes
362  *
363  * Allocates the DMA buffer on the BUS type given earlier to
364  * snd_pcm_lib_preallocate_xxx_pages().
365  *
366  * Returns 1 if the buffer is changed, 0 if not changed, or a negative
367  * code on failure.
368  */
snd_pcm_lib_malloc_pages(struct snd_pcm_substream * substream,size_t size)369 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
370 {
371 	struct snd_pcm_runtime *runtime;
372 	struct snd_dma_buffer *dmab = NULL;
373 
374 	if (PCM_RUNTIME_CHECK(substream))
375 		return -EINVAL;
376 	if (snd_BUG_ON(substream->dma_buffer.dev.type ==
377 		       SNDRV_DMA_TYPE_UNKNOWN))
378 		return -EINVAL;
379 	runtime = substream->runtime;
380 
381 	if (runtime->dma_buffer_p) {
382 		/* perphaps, we might free the large DMA memory region
383 		   to save some space here, but the actual solution
384 		   costs us less time */
385 		if (runtime->dma_buffer_p->bytes >= size) {
386 			runtime->dma_bytes = size;
387 			return 0;	/* ok, do not change */
388 		}
389 		snd_pcm_lib_free_pages(substream);
390 	}
391 	if (substream->dma_buffer.area != NULL &&
392 	    substream->dma_buffer.bytes >= size) {
393 		dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
394 	} else {
395 		dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
396 		if (! dmab)
397 			return -ENOMEM;
398 		dmab->dev = substream->dma_buffer.dev;
399 		if (snd_dma_alloc_pages(substream->dma_buffer.dev.type,
400 					substream->dma_buffer.dev.dev,
401 					size, dmab) < 0) {
402 			kfree(dmab);
403 			return -ENOMEM;
404 		}
405 	}
406 	snd_pcm_set_runtime_buffer(substream, dmab);
407 	runtime->dma_bytes = size;
408 	return 1;			/* area was changed */
409 }
410 
411 EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
412 
413 /**
414  * snd_pcm_lib_free_pages - release the allocated DMA buffer.
415  * @substream: the substream to release the DMA buffer
416  *
417  * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
418  *
419  * Returns zero if successful, or a negative error code on failure.
420  */
snd_pcm_lib_free_pages(struct snd_pcm_substream * substream)421 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
422 {
423 	struct snd_pcm_runtime *runtime;
424 
425 	if (PCM_RUNTIME_CHECK(substream))
426 		return -EINVAL;
427 	runtime = substream->runtime;
428 	if (runtime->dma_area == NULL)
429 		return 0;
430 	if (runtime->dma_buffer_p != &substream->dma_buffer) {
431 		/* it's a newly allocated buffer.  release it now. */
432 		snd_dma_free_pages(runtime->dma_buffer_p);
433 		kfree(runtime->dma_buffer_p);
434 	}
435 	snd_pcm_set_runtime_buffer(substream, NULL);
436 	return 0;
437 }
438 
439 EXPORT_SYMBOL(snd_pcm_lib_free_pages);
440 
_snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream * substream,size_t size,gfp_t gfp_flags)441 int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
442 				      size_t size, gfp_t gfp_flags)
443 {
444 	struct snd_pcm_runtime *runtime;
445 
446 	if (PCM_RUNTIME_CHECK(substream))
447 		return -EINVAL;
448 	runtime = substream->runtime;
449 	if (runtime->dma_area) {
450 		if (runtime->dma_bytes >= size)
451 			return 0; /* already large enough */
452 		vfree(runtime->dma_area);
453 	}
454 	runtime->dma_area = __vmalloc(size, gfp_flags, PAGE_KERNEL);
455 	if (!runtime->dma_area)
456 		return -ENOMEM;
457 	runtime->dma_bytes = size;
458 	return 1;
459 }
460 EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
461 
462 /**
463  * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
464  * @substream: the substream with a buffer allocated by
465  *	snd_pcm_lib_alloc_vmalloc_buffer()
466  */
snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream * substream)467 int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
468 {
469 	struct snd_pcm_runtime *runtime;
470 
471 	if (PCM_RUNTIME_CHECK(substream))
472 		return -EINVAL;
473 	runtime = substream->runtime;
474 	vfree(runtime->dma_area);
475 	runtime->dma_area = NULL;
476 	return 0;
477 }
478 EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
479 
480 /**
481  * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
482  * @substream: the substream with a buffer allocated by
483  *	snd_pcm_lib_alloc_vmalloc_buffer()
484  * @offset: offset in the buffer
485  *
486  * This function is to be used as the page callback in the PCM ops.
487  */
snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream * substream,unsigned long offset)488 struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
489 					  unsigned long offset)
490 {
491 	return vmalloc_to_page(substream->runtime->dma_area + offset);
492 }
493 EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);
494