pcm_memory.c

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/*
 *  Digital Audio (PCM) abstract layer
 *  Copyright (c) by Jaroslav Kysela <[email protected]>
 *
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <asm/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>

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;


/*
 * 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;
    int err;

    /* already reserved? */
    if (snd_dma_get_reserved_buf(dmab, substream->dma_buf_id) > 0) {
        if (dmab->bytes >= size)
            return 0; /* yes */
        /* no, free the reserved block */
        snd_dma_free_pages(dmab);
        dmab->bytes = 0;
    }

    do {
        if ((err = snd_dma_alloc_pages(dmab->dev.type, dmab->dev.dev,
                           size, dmab)) < 0) {
            if (err != -ENOMEM)
                return err; /* fatal error */
        } else
            return 0;
        size >>= 1;
    } while (size >= snd_minimum_buffer);
    dmab->bytes = 0; /* tell error */
    return 0;
}

/*
 * release the preallocated buffer if not yet done.
 */
static void snd_pcm_lib_preallocate_dma_free(struct snd_pcm_substream *substream)
{
    if (substream->dma_buffer.area == NULL)
        return;
    if (substream->dma_buf_id)
        snd_dma_reserve_buf(&substream->dma_buffer, substream->dma_buf_id);
    else
        snd_dma_free_pages(&substream->dma_buffer);
    substream->dma_buffer.area = NULL;
}

int snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
{
    snd_pcm_lib_preallocate_dma_free(substream);
#ifdef CONFIG_SND_VERBOSE_PROCFS
    snd_info_free_entry(substream->proc_prealloc_max_entry);
    substream->proc_prealloc_max_entry = NULL;
    snd_info_free_entry(substream->proc_prealloc_entry);
    substream->proc_prealloc_entry = NULL;
#endif
    return 0;
}

int 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);
    return 0;
}

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;
    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 (snd_dma_alloc_pages(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)
            snd_dma_free_pages(&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;

    if ((entry = snd_info_create_card_entry(substream->pcm->card, "prealloc", substream->proc_root)) != NULL) {
        entry->c.text.read = snd_pcm_lib_preallocate_proc_read;
        entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
        entry->mode |= S_IWUSR;
        entry->private_data = substream;
        if (snd_info_register(entry) < 0) {
            snd_info_free_entry(entry);
            entry = NULL;
        }
    }
    substream->proc_prealloc_entry = entry;
    if ((entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max", substream->proc_root)) != NULL) {
        entry->c.text.read = snd_pcm_lib_preallocate_max_proc_read;
        entry->private_data = substream;
        if (snd_info_register(entry) < 0) {
            snd_info_free_entry(entry);
            entry = NULL;
        }
    }
    substream->proc_prealloc_max_entry = entry;
}

#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 int snd_pcm_lib_preallocate_pages1(struct snd_pcm_substream *substream,
                      size_t size, size_t max)
{

    if (size > 0 && preallocate_dma && substream->number < maximum_substreams)
        preallocate_pcm_pages(substream, size);

    if (substream->dma_buffer.bytes > 0)
        substream->buffer_bytes_max = substream->dma_buffer.bytes;
    substream->dma_max = max;
    preallocate_info_init(substream);
    return 0;
}


int snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
                  int type, struct device *data,
                  size_t size, size_t max)
{
    substream->dma_buffer.dev.type = type;
    substream->dma_buffer.dev.dev = data;
    return snd_pcm_lib_preallocate_pages1(substream, size, max);
}

EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);

int snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
                      int type, void *data,
                      size_t size, size_t max)
{
    struct snd_pcm_substream *substream;
    int stream, err;

    for (stream = 0; stream < 2; stream++)
        for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
            if ((err = snd_pcm_lib_preallocate_pages(substream, type, data, size, max)) < 0)
                return err;
    return 0;
}

EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);

#ifdef CONFIG_SND_DMA_SGBUF

struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
{
    struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);

    unsigned int idx = offset >> PAGE_SHIFT;
    if (idx >= (unsigned int)sgbuf->pages)
        return NULL;
    return sgbuf->page_table[idx];
}

EXPORT_SYMBOL(snd_pcm_sgbuf_ops_page);
#endif /* CONFIG_SND_DMA_SGBUF */

int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
{
    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;

    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 {
        dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
        if (! dmab)
            return -ENOMEM;
        dmab->dev = substream->dma_buffer.dev;
        if (snd_dma_alloc_pages(substream->dma_buffer.dev.type,
                    substream->dma_buffer.dev.dev,
                    size, dmab) < 0) {
            kfree(dmab);
            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);

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) {
        /* it's a newly allocated buffer.  release it now. */
        snd_dma_free_pages(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);

int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
                      size_t size, gfp_t gfp_flags)
{
    struct snd_pcm_runtime *runtime;

    if (PCM_RUNTIME_CHECK(substream))
        return -EINVAL;
    runtime = substream->runtime;
    if (runtime->dma_area) {
        if (runtime->dma_bytes >= size)
            return 0; /* already large enough */
        vfree(runtime->dma_area);
    }
    runtime->dma_area = __vmalloc(size, gfp_flags, PAGE_KERNEL);
    if (!runtime->dma_area)
        return -ENOMEM;
    runtime->dma_bytes = size;
    return 1;
}
EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);

int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime;

    if (PCM_RUNTIME_CHECK(substream))
        return -EINVAL;
    runtime = substream->runtime;
    vfree(runtime->dma_area);
    runtime->dma_area = NULL;
    return 0;
}
EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);

struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
                      unsigned long offset)
{
    return vmalloc_to_page(substream->runtime->dma_area + offset);
}
EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);