1. 根目录:
2. sound
3. core
4. memalloc.c

/*
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *                   Takashi Iwai <tiwai@suse.de>
 * 
 *  Generic memory allocators
 *
 *
 *   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 <linux/slab.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/genalloc.h>
#include <sound/memalloc.h>

/*
 *
 *  Generic memory allocators
 *
 */

/**
 * snd_malloc_pages - allocate pages with the given size
 * @size: the size to allocate in bytes
 * @gfp_flags: the allocation conditions, GFP_XXX
 *
 * Allocates the physically contiguous pages with the given size.
 *
 * Return: The pointer of the buffer, or %NULL if no enough memory.
 */
void *snd_malloc_pages(size_t size, gfp_t gfp_flags)
{
	int pg;

	if (WARN_ON(!size))
		return NULL;
	if (WARN_ON(!gfp_flags))
		return NULL;
	gfp_flags |= __GFP_COMP;	/* compound page lets parts be mapped */
	pg = get_order(size);
	return (void *) __get_free_pages(gfp_flags, pg);
}

/**
 * snd_free_pages - release the pages
 * @ptr: the buffer pointer to release
 * @size: the allocated buffer size
 *
 * Releases the buffer allocated via snd_malloc_pages().
 */
void snd_free_pages(void *ptr, size_t size)
{
	int pg;

	if (ptr == NULL)
		return;
	pg = get_order(size);
	free_pages((unsigned long) ptr, pg);
}

/*
 *
 *  Bus-specific memory allocators
 *
 */

#ifdef CONFIG_HAS_DMA
/* allocate the coherent DMA pages */
static void *snd_malloc_dev_pages(struct device *dev, size_t size, dma_addr_t *dma)
{
	int pg;
	gfp_t gfp_flags;

	if (WARN_ON(!dma))
		return NULL;
	pg = get_order(size);
	gfp_flags = GFP_KERNEL
		| __GFP_COMP	/* compound page lets parts be mapped */
		| __GFP_NORETRY /* don't trigger OOM-killer */
		| __GFP_NOWARN; /* no stack trace print - this call is non-critical */
	return dma_alloc_coherent(dev, PAGE_SIZE << pg, dma, gfp_flags);
}

/* free the coherent DMA pages */
static void snd_free_dev_pages(struct device *dev, size_t size, void *ptr,
			       dma_addr_t dma)
{
	int pg;

	if (ptr == NULL)
		return;
	pg = get_order(size);
	dma_free_coherent(dev, PAGE_SIZE << pg, ptr, dma);
}

#ifdef CONFIG_GENERIC_ALLOCATOR
/**
 * snd_malloc_dev_iram - allocate memory from on-chip internal ram
 * @dmab: buffer allocation record to store the allocated data
 * @size: number of bytes to allocate from the iram
 *
 * This function requires iram phandle provided via of_node
 */
static void snd_malloc_dev_iram(struct snd_dma_buffer *dmab, size_t size)
{
	struct device *dev = dmab->dev.dev;
	struct gen_pool *pool = NULL;

	dmab->area = NULL;
	dmab->addr = 0;

	if (dev->of_node)
		pool = of_get_named_gen_pool(dev->of_node, "iram", 0);

	if (!pool)
		return;

	/* Assign the pool into private_data field */
	dmab->private_data = pool;

	dmab->area = gen_pool_dma_alloc(pool, size, &dmab->addr);
}

/**
 * snd_free_dev_iram - free allocated specific memory from on-chip internal ram
 * @dmab: buffer allocation record to store the allocated data
 */
static void snd_free_dev_iram(struct snd_dma_buffer *dmab)
{
	struct gen_pool *pool = dmab->private_data;

	if (pool && dmab->area)
		gen_pool_free(pool, (unsigned long)dmab->area, dmab->bytes);
}
#endif /* CONFIG_GENERIC_ALLOCATOR */
#endif /* CONFIG_HAS_DMA */

/*
 *
 *  ALSA generic memory management
 *
 */


/**
 * snd_dma_alloc_pages - allocate the buffer area according to the given type
 * @type: the DMA buffer type
 * @device: the device pointer
 * @size: the buffer size to allocate
 * @dmab: buffer allocation record to store the allocated data
 *
 * Calls the memory-allocator function for the corresponding
 * buffer type.
 *
 * Return: Zero if the buffer with the given size is allocated successfully,
 * otherwise a negative value on error.
 */
int snd_dma_alloc_pages(int type, struct device *device, size_t size,
			struct snd_dma_buffer *dmab)
{
	if (WARN_ON(!size))
		return -ENXIO;
	if (WARN_ON(!dmab))
		return -ENXIO;

	dmab->dev.type = type;
	dmab->dev.dev = device;
	dmab->bytes = 0;
	switch (type) {
	case SNDRV_DMA_TYPE_CONTINUOUS:
		dmab->area = snd_malloc_pages(size,
					(__force gfp_t)(unsigned long)device);
		dmab->addr = 0;
		break;
#ifdef CONFIG_HAS_DMA
#ifdef CONFIG_GENERIC_ALLOCATOR
	case SNDRV_DMA_TYPE_DEV_IRAM:
		snd_malloc_dev_iram(dmab, size);
		if (dmab->area)
			break;
		/* Internal memory might have limited size and no enough space,
		 * so if we fail to malloc, try to fetch memory traditionally.
		 */
		dmab->dev.type = SNDRV_DMA_TYPE_DEV;
#endif /* CONFIG_GENERIC_ALLOCATOR */
	case SNDRV_DMA_TYPE_DEV:
		dmab->area = snd_malloc_dev_pages(device, size, &dmab->addr);
		break;
#endif
#ifdef CONFIG_SND_DMA_SGBUF
	case SNDRV_DMA_TYPE_DEV_SG:
		snd_malloc_sgbuf_pages(device, size, dmab, NULL);
		break;
#endif
	default:
		pr_err("snd-malloc: invalid device type %d\n", type);
		dmab->area = NULL;
		dmab->addr = 0;
		return -ENXIO;
	}
	if (! dmab->area)
		return -ENOMEM;
	dmab->bytes = size;
	return 0;
}

/**
 * snd_dma_alloc_pages_fallback - allocate the buffer area according to the given type with fallback
 * @type: the DMA buffer type
 * @device: the device pointer
 * @size: the buffer size to allocate
 * @dmab: buffer allocation record to store the allocated data
 *
 * Calls the memory-allocator function for the corresponding
 * buffer type.  When no space is left, this function reduces the size and
 * tries to allocate again.  The size actually allocated is stored in
 * res_size argument.
 *
 * Return: Zero if the buffer with the given size is allocated successfully,
 * otherwise a negative value on error.
 */
int snd_dma_alloc_pages_fallback(int type, struct device *device, size_t size,
				 struct snd_dma_buffer *dmab)
{
	int err;

	while ((err = snd_dma_alloc_pages(type, device, size, dmab)) < 0) {
		size_t aligned_size;
		if (err != -ENOMEM)
			return err;
		if (size <= PAGE_SIZE)
			return -ENOMEM;
		aligned_size = PAGE_SIZE << get_order(size);
		if (size != aligned_size)
			size = aligned_size;
		else
			size >>= 1;
	}
	if (! dmab->area)
		return -ENOMEM;
	return 0;
}


/**
 * snd_dma_free_pages - release the allocated buffer
 * @dmab: the buffer allocation record to release
 *
 * Releases the allocated buffer via snd_dma_alloc_pages().
 */
void snd_dma_free_pages(struct snd_dma_buffer *dmab)
{
	switch (dmab->dev.type) {
	case SNDRV_DMA_TYPE_CONTINUOUS:
		snd_free_pages(dmab->area, dmab->bytes);
		break;
#ifdef CONFIG_HAS_DMA
#ifdef CONFIG_GENERIC_ALLOCATOR
	case SNDRV_DMA_TYPE_DEV_IRAM:
		snd_free_dev_iram(dmab);
		break;
#endif /* CONFIG_GENERIC_ALLOCATOR */
	case SNDRV_DMA_TYPE_DEV:
		snd_free_dev_pages(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
		break;
#endif
#ifdef CONFIG_SND_DMA_SGBUF
	case SNDRV_DMA_TYPE_DEV_SG:
		snd_free_sgbuf_pages(dmab);
		break;
#endif
	default:
		pr_err("snd-malloc: invalid device type %d\n", dmab->dev.type);
	}
}

/*
 * exports
 */
EXPORT_SYMBOL(snd_dma_alloc_pages);
EXPORT_SYMBOL(snd_dma_alloc_pages_fallback);
EXPORT_SYMBOL(snd_dma_free_pages);

EXPORT_SYMBOL(snd_malloc_pages);
EXPORT_SYMBOL(snd_free_pages);