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1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Digital Audio (PCM) abstract layer
4  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5  */
6 
7 #include <linux/io.h>
8 #include <linux/time.h>
9 #include <linux/init.h>
10 #include <linux/slab.h>
11 #include <linux/moduleparam.h>
12 #include <linux/vmalloc.h>
13 #include <linux/export.h>
14 #include <sound/core.h>
15 #include <sound/pcm.h>
16 #include <sound/info.h>
17 #include <sound/initval.h>
18 #include "pcm_local.h"
19 
20 static int preallocate_dma = 1;
21 module_param(preallocate_dma, int, 0444);
22 MODULE_PARM_DESC(preallocate_dma, "Preallocate DMA memory when the PCM devices are initialized.");
23 
24 static int maximum_substreams = 4;
25 module_param(maximum_substreams, int, 0444);
26 MODULE_PARM_DESC(maximum_substreams, "Maximum substreams with preallocated DMA memory.");
27 
28 static const size_t snd_minimum_buffer = 16384;
29 
30 static unsigned long max_alloc_per_card = 32UL * 1024UL * 1024UL;
31 module_param(max_alloc_per_card, ulong, 0644);
32 MODULE_PARM_DESC(max_alloc_per_card, "Max total allocation bytes per card.");
33 
do_alloc_pages(struct snd_card * card,int type,struct device * dev,size_t size,struct snd_dma_buffer * dmab)34 static int do_alloc_pages(struct snd_card *card, int type, struct device *dev,
35 			  size_t size, struct snd_dma_buffer *dmab)
36 {
37 	int err;
38 
39 	if (max_alloc_per_card &&
40 	    card->total_pcm_alloc_bytes + size > max_alloc_per_card)
41 		return -ENOMEM;
42 
43 	err = snd_dma_alloc_pages(type, dev, size, dmab);
44 	if (!err) {
45 		mutex_lock(&card->memory_mutex);
46 		card->total_pcm_alloc_bytes += dmab->bytes;
47 		mutex_unlock(&card->memory_mutex);
48 	}
49 	return err;
50 }
51 
do_free_pages(struct snd_card * card,struct snd_dma_buffer * dmab)52 static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab)
53 {
54 	if (!dmab->area)
55 		return;
56 	mutex_lock(&card->memory_mutex);
57 	WARN_ON(card->total_pcm_alloc_bytes < dmab->bytes);
58 	card->total_pcm_alloc_bytes -= dmab->bytes;
59 	mutex_unlock(&card->memory_mutex);
60 	snd_dma_free_pages(dmab);
61 	dmab->area = NULL;
62 }
63 
64 /*
65  * try to allocate as the large pages as possible.
66  * stores the resultant memory size in *res_size.
67  *
68  * the minimum size is snd_minimum_buffer.  it should be power of 2.
69  */
preallocate_pcm_pages(struct snd_pcm_substream * substream,size_t size)70 static int preallocate_pcm_pages(struct snd_pcm_substream *substream, size_t size)
71 {
72 	struct snd_dma_buffer *dmab = &substream->dma_buffer;
73 	struct snd_card *card = substream->pcm->card;
74 	size_t orig_size = size;
75 	int err;
76 
77 	do {
78 		err = do_alloc_pages(card, dmab->dev.type, dmab->dev.dev,
79 				     size, dmab);
80 		if (err != -ENOMEM)
81 			return err;
82 		size >>= 1;
83 	} while (size >= snd_minimum_buffer);
84 	dmab->bytes = 0; /* tell error */
85 	pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
86 		substream->pcm->card->number, substream->pcm->device,
87 		substream->stream ? 'c' : 'p', substream->number,
88 		substream->pcm->name, orig_size);
89 	return 0;
90 }
91 
92 /*
93  * release the preallocated buffer if not yet done.
94  */
snd_pcm_lib_preallocate_dma_free(struct snd_pcm_substream * substream)95 static void snd_pcm_lib_preallocate_dma_free(struct snd_pcm_substream *substream)
96 {
97 	do_free_pages(substream->pcm->card, &substream->dma_buffer);
98 }
99 
100 /**
101  * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
102  * @substream: the pcm substream instance
103  *
104  * Releases the pre-allocated buffer of the given substream.
105  */
snd_pcm_lib_preallocate_free(struct snd_pcm_substream * substream)106 void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
107 {
108 	snd_pcm_lib_preallocate_dma_free(substream);
109 }
110 
111 /**
112  * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
113  * @pcm: the pcm instance
114  *
115  * Releases all the pre-allocated buffers on the given pcm.
116  */
snd_pcm_lib_preallocate_free_for_all(struct snd_pcm * pcm)117 void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
118 {
119 	struct snd_pcm_substream *substream;
120 	int stream;
121 
122 	for (stream = 0; stream < 2; stream++)
123 		for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
124 			snd_pcm_lib_preallocate_free(substream);
125 }
126 EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
127 
128 #ifdef CONFIG_SND_VERBOSE_PROCFS
129 /*
130  * read callback for prealloc proc file
131  *
132  * prints the current allocated size in kB.
133  */
snd_pcm_lib_preallocate_proc_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)134 static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
135 					      struct snd_info_buffer *buffer)
136 {
137 	struct snd_pcm_substream *substream = entry->private_data;
138 	snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
139 }
140 
141 /*
142  * read callback for prealloc_max proc file
143  *
144  * prints the maximum allowed size in kB.
145  */
snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)146 static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
147 						  struct snd_info_buffer *buffer)
148 {
149 	struct snd_pcm_substream *substream = entry->private_data;
150 	snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
151 }
152 
153 /*
154  * write callback for prealloc proc file
155  *
156  * accepts the preallocation size in kB.
157  */
snd_pcm_lib_preallocate_proc_write(struct snd_info_entry * entry,struct snd_info_buffer * buffer)158 static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
159 					       struct snd_info_buffer *buffer)
160 {
161 	struct snd_pcm_substream *substream = entry->private_data;
162 	struct snd_card *card = substream->pcm->card;
163 	char line[64], str[64];
164 	size_t size;
165 	struct snd_dma_buffer new_dmab;
166 
167 	mutex_lock(&substream->pcm->open_mutex);
168 	if (substream->runtime) {
169 		buffer->error = -EBUSY;
170 		goto unlock;
171 	}
172 	if (!snd_info_get_line(buffer, line, sizeof(line))) {
173 		snd_info_get_str(str, line, sizeof(str));
174 		size = simple_strtoul(str, NULL, 10) * 1024;
175 		if ((size != 0 && size < 8192) || size > substream->dma_max) {
176 			buffer->error = -EINVAL;
177 			goto unlock;
178 		}
179 		if (substream->dma_buffer.bytes == size)
180 			goto unlock;
181 		memset(&new_dmab, 0, sizeof(new_dmab));
182 		new_dmab.dev = substream->dma_buffer.dev;
183 		if (size > 0) {
184 			if (do_alloc_pages(card,
185 					   substream->dma_buffer.dev.type,
186 					   substream->dma_buffer.dev.dev,
187 					   size, &new_dmab) < 0) {
188 				buffer->error = -ENOMEM;
189 				goto unlock;
190 			}
191 			substream->buffer_bytes_max = size;
192 		} else {
193 			substream->buffer_bytes_max = UINT_MAX;
194 		}
195 		if (substream->dma_buffer.area)
196 			do_free_pages(card, &substream->dma_buffer);
197 		substream->dma_buffer = new_dmab;
198 	} else {
199 		buffer->error = -EINVAL;
200 	}
201  unlock:
202 	mutex_unlock(&substream->pcm->open_mutex);
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 	entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
210 					   substream->proc_root);
211 	if (entry) {
212 		snd_info_set_text_ops(entry, substream,
213 				      snd_pcm_lib_preallocate_proc_read);
214 		entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
215 		entry->mode |= 0200;
216 	}
217 	entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
218 					   substream->proc_root);
219 	if (entry)
220 		snd_info_set_text_ops(entry, substream,
221 				      snd_pcm_lib_preallocate_max_proc_read);
222 }
223 
224 #else /* !CONFIG_SND_VERBOSE_PROCFS */
225 #define preallocate_info_init(s)
226 #endif /* CONFIG_SND_VERBOSE_PROCFS */
227 
228 /*
229  * pre-allocate the buffer and create a proc file for the substream
230  */
preallocate_pages(struct snd_pcm_substream * substream,int type,struct device * data,size_t size,size_t max,bool managed)231 static void preallocate_pages(struct snd_pcm_substream *substream,
232 			      int type, struct device *data,
233 			      size_t size, size_t max, bool managed)
234 {
235 	if (snd_BUG_ON(substream->dma_buffer.dev.type))
236 		return;
237 
238 	substream->dma_buffer.dev.type = type;
239 	substream->dma_buffer.dev.dev = data;
240 
241 	if (size > 0 && preallocate_dma && substream->number < maximum_substreams)
242 		preallocate_pcm_pages(substream, size);
243 
244 	if (substream->dma_buffer.bytes > 0)
245 		substream->buffer_bytes_max = substream->dma_buffer.bytes;
246 	substream->dma_max = max;
247 	if (max > 0)
248 		preallocate_info_init(substream);
249 	if (managed)
250 		substream->managed_buffer_alloc = 1;
251 }
252 
preallocate_pages_for_all(struct snd_pcm * pcm,int type,void * data,size_t size,size_t max,bool managed)253 static void preallocate_pages_for_all(struct snd_pcm *pcm, int type,
254 				      void *data, size_t size, size_t max,
255 				      bool managed)
256 {
257 	struct snd_pcm_substream *substream;
258 	int stream;
259 
260 	for (stream = 0; stream < 2; stream++)
261 		for (substream = pcm->streams[stream].substream; substream;
262 		     substream = substream->next)
263 			preallocate_pages(substream, type, data, size, max,
264 					  managed);
265 }
266 
267 /**
268  * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
269  * @substream: the pcm substream instance
270  * @type: DMA type (SNDRV_DMA_TYPE_*)
271  * @data: DMA type dependent data
272  * @size: the requested pre-allocation size in bytes
273  * @max: the max. allowed pre-allocation size
274  *
275  * Do pre-allocation for the given DMA buffer type.
276  */
snd_pcm_lib_preallocate_pages(struct snd_pcm_substream * substream,int type,struct device * data,size_t size,size_t max)277 void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
278 				  int type, struct device *data,
279 				  size_t size, size_t max)
280 {
281 	preallocate_pages(substream, type, data, size, max, false);
282 }
283 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
284 
285 /**
286  * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
287  * @pcm: the pcm instance
288  * @type: DMA type (SNDRV_DMA_TYPE_*)
289  * @data: DMA type dependent data
290  * @size: the requested pre-allocation size in bytes
291  * @max: the max. allowed pre-allocation size
292  *
293  * Do pre-allocation to all substreams of the given pcm for the
294  * specified DMA type.
295  */
snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm * pcm,int type,void * data,size_t size,size_t max)296 void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
297 					  int type, void *data,
298 					  size_t size, size_t max)
299 {
300 	preallocate_pages_for_all(pcm, type, data, size, max, false);
301 }
302 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
303 
304 /**
305  * snd_pcm_set_managed_buffer - set up buffer management for a substream
306  * @substream: the pcm substream instance
307  * @type: DMA type (SNDRV_DMA_TYPE_*)
308  * @data: DMA type dependent data
309  * @size: the requested pre-allocation size in bytes
310  * @max: the max. allowed pre-allocation size
311  *
312  * Do pre-allocation for the given DMA buffer type, and set the managed
313  * buffer allocation mode to the given substream.
314  * In this mode, PCM core will allocate a buffer automatically before PCM
315  * hw_params ops call, and release the buffer after PCM hw_free ops call
316  * as well, so that the driver doesn't need to invoke the allocation and
317  * the release explicitly in its callback.
318  * When a buffer is actually allocated before the PCM hw_params call, it
319  * turns on the runtime buffer_changed flag for drivers changing their h/w
320  * parameters accordingly.
321  */
snd_pcm_set_managed_buffer(struct snd_pcm_substream * substream,int type,struct device * data,size_t size,size_t max)322 void snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type,
323 				struct device *data, size_t size, size_t max)
324 {
325 	preallocate_pages(substream, type, data, size, max, true);
326 }
327 EXPORT_SYMBOL(snd_pcm_set_managed_buffer);
328 
329 /**
330  * snd_pcm_set_managed_buffer_all - set up buffer management for all substreams
331  *	for all substreams
332  * @pcm: the pcm instance
333  * @type: DMA type (SNDRV_DMA_TYPE_*)
334  * @data: DMA type dependent data
335  * @size: the requested pre-allocation size in bytes
336  * @max: the max. allowed pre-allocation size
337  *
338  * Do pre-allocation to all substreams of the given pcm for the specified DMA
339  * type and size, and set the managed_buffer_alloc flag to each substream.
340  */
snd_pcm_set_managed_buffer_all(struct snd_pcm * pcm,int type,struct device * data,size_t size,size_t max)341 void snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
342 				    struct device *data,
343 				    size_t size, size_t max)
344 {
345 	preallocate_pages_for_all(pcm, type, data, size, max, true);
346 }
347 EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
348 
349 #ifdef CONFIG_SND_DMA_SGBUF
350 /*
351  * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
352  * @substream: the pcm substream instance
353  * @offset: the buffer offset
354  *
355  * Used as the page callback of PCM ops.
356  *
357  * Return: The page struct at the given buffer offset. %NULL on failure.
358  */
snd_pcm_sgbuf_ops_page(struct snd_pcm_substream * substream,unsigned long offset)359 struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
360 {
361 	struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
362 
363 	unsigned int idx = offset >> PAGE_SHIFT;
364 	if (idx >= (unsigned int)sgbuf->pages)
365 		return NULL;
366 	return sgbuf->page_table[idx];
367 }
368 #endif /* CONFIG_SND_DMA_SGBUF */
369 
370 /**
371  * snd_pcm_lib_malloc_pages - allocate the DMA buffer
372  * @substream: the substream to allocate the DMA buffer to
373  * @size: the requested buffer size in bytes
374  *
375  * Allocates the DMA buffer on the BUS type given earlier to
376  * snd_pcm_lib_preallocate_xxx_pages().
377  *
378  * Return: 1 if the buffer is changed, 0 if not changed, or a negative
379  * code on failure.
380  */
snd_pcm_lib_malloc_pages(struct snd_pcm_substream * substream,size_t size)381 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
382 {
383 	struct snd_card *card;
384 	struct snd_pcm_runtime *runtime;
385 	struct snd_dma_buffer *dmab = NULL;
386 
387 	if (PCM_RUNTIME_CHECK(substream))
388 		return -EINVAL;
389 	if (snd_BUG_ON(substream->dma_buffer.dev.type ==
390 		       SNDRV_DMA_TYPE_UNKNOWN))
391 		return -EINVAL;
392 	runtime = substream->runtime;
393 	card = substream->pcm->card;
394 
395 	if (runtime->dma_buffer_p) {
396 		/* perphaps, we might free the large DMA memory region
397 		   to save some space here, but the actual solution
398 		   costs us less time */
399 		if (runtime->dma_buffer_p->bytes >= size) {
400 			runtime->dma_bytes = size;
401 			return 0;	/* ok, do not change */
402 		}
403 		snd_pcm_lib_free_pages(substream);
404 	}
405 	if (substream->dma_buffer.area != NULL &&
406 	    substream->dma_buffer.bytes >= size) {
407 		dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
408 	} else {
409 		dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
410 		if (! dmab)
411 			return -ENOMEM;
412 		dmab->dev = substream->dma_buffer.dev;
413 		if (do_alloc_pages(card,
414 				   substream->dma_buffer.dev.type,
415 				   substream->dma_buffer.dev.dev,
416 				   size, dmab) < 0) {
417 			kfree(dmab);
418 			return -ENOMEM;
419 		}
420 	}
421 	snd_pcm_set_runtime_buffer(substream, dmab);
422 	runtime->dma_bytes = size;
423 	return 1;			/* area was changed */
424 }
425 EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
426 
427 /**
428  * snd_pcm_lib_free_pages - release the allocated DMA buffer.
429  * @substream: the substream to release the DMA buffer
430  *
431  * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
432  *
433  * Return: Zero if successful, or a negative error code on failure.
434  */
snd_pcm_lib_free_pages(struct snd_pcm_substream * substream)435 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
436 {
437 	struct snd_card *card = substream->pcm->card;
438 	struct snd_pcm_runtime *runtime;
439 
440 	if (PCM_RUNTIME_CHECK(substream))
441 		return -EINVAL;
442 	runtime = substream->runtime;
443 	if (runtime->dma_area == NULL)
444 		return 0;
445 	if (runtime->dma_buffer_p != &substream->dma_buffer) {
446 		/* it's a newly allocated buffer.  release it now. */
447 		do_free_pages(card, runtime->dma_buffer_p);
448 		kfree(runtime->dma_buffer_p);
449 	}
450 	snd_pcm_set_runtime_buffer(substream, NULL);
451 	return 0;
452 }
453 EXPORT_SYMBOL(snd_pcm_lib_free_pages);
454 
_snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream * substream,size_t size,gfp_t gfp_flags)455 int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
456 				      size_t size, gfp_t gfp_flags)
457 {
458 	struct snd_pcm_runtime *runtime;
459 
460 	if (PCM_RUNTIME_CHECK(substream))
461 		return -EINVAL;
462 	runtime = substream->runtime;
463 	if (runtime->dma_area) {
464 		if (runtime->dma_bytes >= size)
465 			return 0; /* already large enough */
466 		vfree(runtime->dma_area);
467 	}
468 	runtime->dma_area = __vmalloc(size, gfp_flags);
469 	if (!runtime->dma_area)
470 		return -ENOMEM;
471 	runtime->dma_bytes = size;
472 	return 1;
473 }
474 EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
475 
476 /**
477  * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
478  * @substream: the substream with a buffer allocated by
479  *	snd_pcm_lib_alloc_vmalloc_buffer()
480  *
481  * Return: Zero if successful, or a negative error code on failure.
482  */
snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream * substream)483 int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
484 {
485 	struct snd_pcm_runtime *runtime;
486 
487 	if (PCM_RUNTIME_CHECK(substream))
488 		return -EINVAL;
489 	runtime = substream->runtime;
490 	vfree(runtime->dma_area);
491 	runtime->dma_area = NULL;
492 	return 0;
493 }
494 EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
495 
496 /**
497  * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
498  * @substream: the substream with a buffer allocated by
499  *	snd_pcm_lib_alloc_vmalloc_buffer()
500  * @offset: offset in the buffer
501  *
502  * This function is to be used as the page callback in the PCM ops.
503  *
504  * Return: The page struct, or %NULL on failure.
505  */
snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream * substream,unsigned long offset)506 struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
507 					  unsigned long offset)
508 {
509 	return vmalloc_to_page(substream->runtime->dma_area + offset);
510 }
511 EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);
512