// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Digital Audio (PCM) abstract layer
* Copyright (c) by Jaroslav Kysela <[email protected]>
*/
#include <linux/io.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/moduleparam.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 void __update_allocated_size(struct snd_card *card, ssize_t bytes)
{
card->total_pcm_alloc_bytes += bytes;
}
static void update_allocated_size(struct snd_card *card, ssize_t bytes)
{
guard(mutex)(&card->memory_mutex);
__update_allocated_size(card, bytes);
}
static void decrease_allocated_size(struct snd_card *card, size_t bytes)
{
guard(mutex)(&card->memory_mutex);
WARN_ON(card->total_pcm_alloc_bytes < bytes);
__update_allocated_size(card, -(ssize_t)bytes);
}
static int do_alloc_pages(struct snd_card *card, int type, struct device *dev,
int str, size_t size, struct snd_dma_buffer *dmab)
{
enum dma_data_direction dir;
int err;
/* check and reserve the requested size */
scoped_guard(mutex, &card->memory_mutex) {
if (max_alloc_per_card &&
card->total_pcm_alloc_bytes + size > max_alloc_per_card)
return -ENOMEM;
__update_allocated_size(card, size);
}
if (str == SNDRV_PCM_STREAM_PLAYBACK)
dir = DMA_TO_DEVICE;
else
dir = DMA_FROM_DEVICE;
err = snd_dma_alloc_dir_pages(type, dev, dir, size, dmab);
if (!err) {
/* the actual allocation size might be bigger than requested,
* and we need to correct the account
*/
if (dmab->bytes != size)
update_allocated_size(card, dmab->bytes - size);
} else {
/* take back on allocation failure */
decrease_allocated_size(card, size);
}
return err;
}
static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab)
{
if (!dmab->area)
return;
decrease_allocated_size(card, dmab->bytes);
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, bool no_fallback)
{
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,
substream->stream, size, dmab);
if (err != -ENOMEM)
return err;
if (no_fallback)
break;
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 -ENOMEM;
}
/**
* 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)
{
do_free_pages(substream->pcm->card, &substream->dma_buffer);
}
/**
* 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_each_pcm_substream(pcm, stream, substream)
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];
unsigned long size;
struct snd_dma_buffer new_dmab;
guard(mutex)(&substream->pcm->open_mutex);
if (substream->runtime) {
buffer->error = -EBUSY;
return;
}
if (!snd_info_get_line(buffer, line, sizeof(line))) {
snd_info_get_str(str, line, sizeof(str));
buffer->error = kstrtoul(str, 10, &size);
if (buffer->error != 0)
return;
size *= 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,
substream->stream,
size, &new_dmab) < 0) {
buffer->error = -ENOMEM;
pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %lu\n",
substream->pcm->card->number, substream->pcm->device,
substream->stream ? 'c' : 'p', substream->number,
substream->pcm->name, size);
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 */
static inline void preallocate_info_init(struct snd_pcm_substream *substream)
{
}
#endif /* CONFIG_SND_VERBOSE_PROCFS */
/*
* pre-allocate the buffer and create a proc file for the substream
*/
static int preallocate_pages(struct snd_pcm_substream *substream,
int type, struct device *data,
size_t size, size_t max, bool managed)
{
int err;
if (snd_BUG_ON(substream->dma_buffer.dev.type))
return -EINVAL;
substream->dma_buffer.dev.type = type;
substream->dma_buffer.dev.dev = data;
if (size > 0) {
if (!max) {
/* no fallback, only also inform -ENOMEM */
err = preallocate_pcm_pages(substream, size, true);
if (err < 0)
return err;
} else if (preallocate_dma &&
substream->number < maximum_substreams) {
err = preallocate_pcm_pages(substream, size, false);
if (err < 0 && err != -ENOMEM)
return err;
}
}
if (substream->dma_buffer.bytes > 0)
substream->buffer_bytes_max = substream->dma_buffer.bytes;
substream->dma_max = max;
if (max > 0)
preallocate_info_init(substream);
if (managed)
substream->managed_buffer_alloc = 1;
return 0;
}
static int preallocate_pages_for_all(struct snd_pcm *pcm, int type,
void *data, size_t size, size_t max,
bool managed)
{
struct snd_pcm_substream *substream;
int stream, err;
for_each_pcm_substream(pcm, stream, substream) {
err = preallocate_pages(substream, type, data, size, max, managed);
if (err < 0)
return err;
}
return 0;
}
/**
* snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
* @substream: the pcm substream instance
* @type: DMA type (SNDRV_DMA_TYPE_*)
* @data: DMA type dependent data
* @size: the requested pre-allocation size in bytes
* @max: the max. allowed pre-allocation size
*
* Do pre-allocation for the given DMA buffer type.
*/
void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
int type, struct device *data,
size_t size, size_t max)
{
preallocate_pages(substream, type, data, size, max, false);
}
EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
/**
* snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
* @pcm: the pcm instance
* @type: DMA type (SNDRV_DMA_TYPE_*)
* @data: DMA type dependent data
* @size: the requested pre-allocation size in bytes
* @max: the max. allowed pre-allocation size
*
* Do pre-allocation to all substreams of the given pcm for the
* specified DMA type.
*/
void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
int type, void *data,
size_t size, size_t max)
{
preallocate_pages_for_all(pcm, type, data, size, max, false);
}
EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
/**
* snd_pcm_set_managed_buffer - set up buffer management for a substream
* @substream: the pcm substream instance
* @type: DMA type (SNDRV_DMA_TYPE_*)
* @data: DMA type dependent data
* @size: the requested pre-allocation size in bytes
* @max: the max. allowed pre-allocation size
*
* Do pre-allocation for the given DMA buffer type, and set the managed
* buffer allocation mode to the given substream.
* In this mode, PCM core will allocate a buffer automatically before PCM
* hw_params ops call, and release the buffer after PCM hw_free ops call
* as well, so that the driver doesn't need to invoke the allocation and
* the release explicitly in its callback.
* When a buffer is actually allocated before the PCM hw_params call, it
* turns on the runtime buffer_changed flag for drivers changing their h/w
* parameters accordingly.
*
* When @size is non-zero and @max is zero, this tries to allocate for only
* the exact buffer size without fallback, and may return -ENOMEM.
* Otherwise, the function tries to allocate smaller chunks if the allocation
* fails. This is the behavior of snd_pcm_set_fixed_buffer().
*
* When both @size and @max are zero, the function only sets up the buffer
* for later dynamic allocations. It's used typically for buffers with
* SNDRV_DMA_TYPE_VMALLOC type.
*
* Upon successful buffer allocation and setup, the function returns 0.
*
* Return: zero if successful, or a negative error code
*/
int snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type,
struct device *data, size_t size, size_t max)
{
return preallocate_pages(substream, type, data, size, max, true);
}
EXPORT_SYMBOL(snd_pcm_set_managed_buffer);
/**
* snd_pcm_set_managed_buffer_all - set up buffer management for all substreams
* for all substreams
* @pcm: the pcm instance
* @type: DMA type (SNDRV_DMA_TYPE_*)
* @data: DMA type dependent data
* @size: the requested pre-allocation size in bytes
* @max: the max. allowed pre-allocation size
*
* Do pre-allocation to all substreams of the given pcm for the specified DMA
* type and size, and set the managed_buffer_alloc flag to each substream.
*
* Return: zero if successful, or a negative error code
*/
int snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
struct device *data,
size_t size, size_t max)
{
return preallocate_pages_for_all(pcm, type, data, size, max, true);
}
EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
/**
* snd_pcm_lib_malloc_pages - allocate the DMA buffer
* @substream: the substream to allocate the DMA buffer to
* @size: the requested buffer size in bytes
*
* Allocates the DMA buffer on the BUS type given earlier to
* snd_pcm_lib_preallocate_xxx_pages().
*
* Return: 1 if the buffer is changed, 0 if not changed, or a negative
* code on failure.
*/
int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
{
struct snd_card *card;
struct snd_pcm_runtime *runtime;
struct snd_dma_buffer *dmab = NULL;
if (PCM_RUNTIME_CHECK(substream))
return -EINVAL;
if (snd_BUG_ON(substream->dma_buffer.dev.type ==
SNDRV_DMA_TYPE_UNKNOWN))
return -EINVAL;
runtime = substream->runtime;
card = substream->pcm->card;
if (runtime->dma_buffer_p) {
/* perphaps, we might free the large DMA memory region
to save some space here, but the actual solution
costs us less time */
if (runtime->dma_buffer_p->bytes >= size) {
runtime->dma_bytes = size;
return 0; /* ok, do not change */
}
snd_pcm_lib_free_pages(substream);
}
if (substream->dma_buffer.area != NULL &&
substream->dma_buffer.bytes >= size) {
dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
} else {
/* dma_max=0 means the fixed size preallocation */
if (substream->dma_buffer.area && !substream->dma_max)
return -ENOMEM;
dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
if (! dmab)
return -ENOMEM;
dmab->dev = substream->dma_buffer.dev;
if (do_alloc_pages(card,
substream->dma_buffer.dev.type,
substream->dma_buffer.dev.dev,
substream->stream,
size, dmab) < 0) {
kfree(dmab);
pr_debug("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, size);
return -ENOMEM;
}
}
snd_pcm_set_runtime_buffer(substream, dmab);
runtime->dma_bytes = size;
return 1; /* area was changed */
}
EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
/**
* snd_pcm_lib_free_pages - release the allocated DMA buffer.
* @substream: the substream to release the DMA buffer
*
* Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
*
* Return: Zero if successful, or a negative error code on failure.
*/
int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime;
if (PCM_RUNTIME_CHECK(substream))
return -EINVAL;
runtime = substream->runtime;
if (runtime->dma_area == NULL)
return 0;
if (runtime->dma_buffer_p != &substream->dma_buffer) {
struct snd_card *card = substream->pcm->card;
/* it's a newly allocated buffer. release it now. */
do_free_pages(card, runtime->dma_buffer_p);
kfree(runtime->dma_buffer_p);
}
snd_pcm_set_runtime_buffer(substream, NULL);
return 0;
}
EXPORT_SYMBOL(snd_pcm_lib_free_pages);
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