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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Digital Audio (PCM) abstract layer
* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
*/
#include <linux/io.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/moduleparam.h>
#include <linux/vmalloc.h>
#include <linux/export.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/info.h>
#include <sound/initval.h>
#include "pcm_local.h"
static int preallocate_dma = 1;
module_param(preallocate_dma, int, 0444);
MODULE_PARM_DESC(preallocate_dma, "Preallocate DMA memory when the PCM devices are initialized.");
static int maximum_substreams = 4;
module_param(maximum_substreams, int, 0444);
MODULE_PARM_DESC(maximum_substreams, "Maximum substreams with preallocated DMA memory.");
static const size_t snd_minimum_buffer = 16384;
static unsigned long max_alloc_per_card = 32UL * 1024UL * 1024UL;
module_param(max_alloc_per_card, ulong, 0644);
MODULE_PARM_DESC(max_alloc_per_card, "Max total allocation bytes per card.");
static int do_alloc_pages(struct snd_card *card, int type, struct device *dev,
size_t size, struct snd_dma_buffer *dmab)
{
int err;
if (max_alloc_per_card &&
card->total_pcm_alloc_bytes + size > max_alloc_per_card)
return -ENOMEM;
err = snd_dma_alloc_pages(type, dev, size, dmab);
if (!err) {
mutex_lock(&card->memory_mutex);
card->total_pcm_alloc_bytes += dmab->bytes;
mutex_unlock(&card->memory_mutex);
}
return err;
}
static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab)
{
if (!dmab->area)
return;
mutex_lock(&card->memory_mutex);
WARN_ON(card->total_pcm_alloc_bytes < dmab->bytes);
card->total_pcm_alloc_bytes -= dmab->bytes;
mutex_unlock(&card->memory_mutex);
snd_dma_free_pages(dmab);
dmab->area = NULL;
}
/*
* try to allocate as the large pages as possible.
* stores the resultant memory size in *res_size.
*
* the minimum size is snd_minimum_buffer. it should be power of 2.
*/
static int preallocate_pcm_pages(struct snd_pcm_substream *substream, size_t size)
{
struct snd_dma_buffer *dmab = &substream->dma_buffer;
struct snd_card *card = substream->pcm->card;
size_t orig_size = size;
int err;
do {
err = do_alloc_pages(card, dmab->dev.type, dmab->dev.dev,
size, dmab);
if (err != -ENOMEM)
return err;
size >>= 1;
} while (size >= snd_minimum_buffer);
dmab->bytes = 0; /* tell error */
pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
substream->pcm->card->number, substream->pcm->device,
substream->stream ? 'c' : 'p', substream->number,
substream->pcm->name, orig_size);
return 0;
}
/*
* release the preallocated buffer if not yet done.
*/
static void snd_pcm_lib_preallocate_dma_free(struct snd_pcm_substream *substream)
{
do_free_pages(substream->pcm->card, &substream->dma_buffer);
}
/**
* snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
* @substream: the pcm substream instance
*
* Releases the pre-allocated buffer of the given substream.
*/
void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
{
snd_pcm_lib_preallocate_dma_free(substream);
}
/**
* snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
* @pcm: the pcm instance
*
* Releases all the pre-allocated buffers on the given pcm.
*/
void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
{
struct snd_pcm_substream *substream;
int stream;
for (stream = 0; stream < 2; stream++)
for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
snd_pcm_lib_preallocate_free(substream);
}
EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
#ifdef CONFIG_SND_VERBOSE_PROCFS
/*
* read callback for prealloc proc file
*
* prints the current allocated size in kB.
*/
static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
struct snd_pcm_substream *substream = entry->private_data;
snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
}
/*
* read callback for prealloc_max proc file
*
* prints the maximum allowed size in kB.
*/
static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
struct snd_pcm_substream *substream = entry->private_data;
snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
}
/*
* write callback for prealloc proc file
*
* accepts the preallocation size in kB.
*/
static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
struct snd_pcm_substream *substream = entry->private_data;
struct snd_card *card = substream->pcm->card;
char line[64], str[64];
size_t size;
struct snd_dma_buffer new_dmab;
if (substream->runtime) {
buffer->error = -EBUSY;
return;
}
if (!snd_info_get_line(buffer, line, sizeof(line))) {
snd_info_get_str(str, line, sizeof(str));
size = simple_strtoul(str, NULL, 10) * 1024;
if ((size != 0 && size < 8192) || size > substream->dma_max) {
buffer->error = -EINVAL;
return;
}
if (substream->dma_buffer.bytes == size)
return;
memset(&new_dmab, 0, sizeof(new_dmab));
new_dmab.dev = substream->dma_buffer.dev;
if (size > 0) {
if (do_alloc_pages(card,
substream->dma_buffer.dev.type,
substream->dma_buffer.dev.dev,
size, &new_dmab) < 0) {
buffer->error = -ENOMEM;
return;
}
substream->buffer_bytes_max = size;
} else {
substream->buffer_bytes_max = UINT_MAX;
}
if (substream->dma_buffer.area)
do_free_pages(card, &substream->dma_buffer);
substream->dma_buffer = new_dmab;
} else {
buffer->error = -EINVAL;
}
}
static inline void preallocate_info_init(struct snd_pcm_substream *substream)
{
struct snd_info_entry *entry;
entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
substream->proc_root);
if (entry) {
snd_info_set_text_ops(entry, substream,
snd_pcm_lib_preallocate_proc_read);
entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
entry->mode |= 0200;
}
entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
substream->proc_root);
if (entry)
snd_info_set_text_ops(entry, substream,
snd_pcm_lib_preallocate_max_proc_read);
}
#else /* !CONFIG_SND_VERBOSE_PROCFS */
#define preallocate_info_init(s)
#endif /* CONFIG_SND_VERBOSE_PROCFS */
/*
* pre-allocate the buffer and create a proc file for the substream
*/
static void preallocate_pages(struct snd_pcm_substream *substream,
int type,
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