memalloc.c

linux 内核源代码

/*
 *  Copyright (c) by Jaroslav Kysela <[e-mail]>
 *                   Takashi Iwai <[e-mail]>
 * 
 *  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/module.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>
#include <linux/dma-mapping.h>
#include <linux/moduleparam.h>
#include <linux/mutex.h>
#include <sound/memalloc.h>
#ifdef CONFIG_SBUS
#include <asm/sbus.h>
#endif


MODULE_AUTHOR("Takashi Iwai <[e-mail]>, Jaroslav Kysela <[e-mail]>");
MODULE_DESCRIPTION("Memory allocator for ALSA system.");
MODULE_LICENSE("GPL");


/*
 */

void *snd_malloc_sgbuf_pages(struct device *device,
                             size_t size, struct snd_dma_buffer *dmab,
			     size_t *res_size);
int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab);

/*
 */

static DEFINE_MUTEX(list_mutex);
static LIST_HEAD(mem_list_head);

/* buffer preservation list */
struct snd_mem_list {
	struct snd_dma_buffer buffer;
	unsigned int id;
	struct list_head list;
};

/* id for pre-allocated buffers */
#define SNDRV_DMA_DEVICE_UNUSED (unsigned int)-1

#ifdef CONFIG_SND_DEBUG
#define __ASTRING__(x) #x
#define snd_assert(expr, args...) do {\
	if (!(expr)) {\
		printk(KERN_ERR "snd-malloc: BUG? (%s) (called from %p)\n", __ASTRING__(expr), __builtin_return_address(0));\
		args;\
	}\
} while (0)
#else
#define snd_assert(expr, args...) /**/
#endif

/*
 *  Hacks
 */

#if defined(__i386__)
/*
 * A hack to allocate large buffers via dma_alloc_coherent()
 *
 * since dma_alloc_coherent always tries GFP_DMA when the requested
 * pci memory region is below 32bit, it happens quite often that even
 * 2 order of pages cannot be allocated.
 *
 * so in the following, we allocate at first without dma_mask, so that
 * allocation will be done without GFP_DMA.  if the area doesn't match
 * with the requested region, then realloate with the original dma_mask
 * again.
 *
 * Really, we want to move this type of thing into dma_alloc_coherent()
 * so dma_mask doesn't have to be messed with.
 */

static void *snd_dma_hack_alloc_coherent(struct device *dev, size_t size,
					 dma_addr_t *dma_handle,
					 gfp_t flags)
{
	void *ret;
	u64 dma_mask, coherent_dma_mask;

	if (dev == NULL || !dev->dma_mask)
		return dma_alloc_coherent(dev, size, dma_handle, flags);
	dma_mask = *dev->dma_mask;
	coherent_dma_mask = dev->coherent_dma_mask;
	*dev->dma_mask = 0xffffffff; 	/* do without masking */
	dev->coherent_dma_mask = 0xffffffff; 	/* do without masking */
	ret = dma_alloc_coherent(dev, size, dma_handle, flags);
	*dev->dma_mask = dma_mask;	/* restore */
	dev->coherent_dma_mask = coherent_dma_mask;	/* restore */
	if (ret) {
		/* obtained address is out of range? */
		if (((unsigned long)*dma_handle + size - 1) & ~dma_mask) {
			/* reallocate with the proper mask */
			dma_free_coherent(dev, size, ret, *dma_handle);
			ret = dma_alloc_coherent(dev, size, dma_handle, flags);
		}
	} else {
		/* wish to success now with the proper mask... */
		if (dma_mask != 0xffffffffUL) {
			/* allocation with GFP_ATOMIC to avoid the long stall */
			flags &= ~GFP_KERNEL;
			flags |= GFP_ATOMIC;
			ret = dma_alloc_coherent(dev, size, dma_handle, flags);
		}
	}
	return ret;
}

/* redefine dma_alloc_coherent for some architectures */
#undef dma_alloc_coherent
#define dma_alloc_coherent snd_dma_hack_alloc_coherent

#endif /* arch */

/*
 *
 *  Generic memory allocators
 *
 */

static long snd_allocated_pages; /* holding the number of allocated pages */

static inline void inc_snd_pages(int order)
{
	snd_allocated_pages += 1 << order;
}

static inline void dec_snd_pages(int order)
{
	snd_allocated_pages -= 1 << order;
}

/**
 * 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.
 *
 * Returns the pointer of the buffer, or NULL if no enoguh memory.
 */
void *snd_malloc_pages(size_t size, gfp_t gfp_flags)
{
	int pg;
	void *res;

	snd_assert(size > 0, return NULL);
	snd_assert(gfp_flags != 0, return NULL);
	gfp_flags |= __GFP_COMP;	/* compound page lets parts be mapped */
	pg = get_order(size);
	if ((res = (void *) __get_free_pages(gfp_flags, pg)) != NULL)
		inc_snd_pages(pg);
	return res;
}

/**
 * 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);
	dec_snd_pages(pg);
	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;
	void *res;
	gfp_t gfp_flags;

	snd_assert(size > 0, return NULL);
	snd_assert(dma != NULL, 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 */
	res = dma_alloc_coherent(dev, PAGE_SIZE << pg, dma, gfp_flags);
	if (res != NULL)
		inc_snd_pages(pg);

	return res;
}

/* 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);
	dec_snd_pages(pg);
	dma_free_coherent(dev, PAGE_SIZE << pg, ptr, dma);
}
#endif /* CONFIG_HAS_DMA */

#ifdef CONFIG_SBUS

static void *snd_malloc_sbus_pages(struct device *dev, size_t size,
				   dma_addr_t *dma_addr)
{
	struct sbus_dev *sdev = (struct sbus_dev *)dev;
	int pg;
	void *res;

	snd_assert(size > 0, return NULL);
	snd_assert(dma_addr != NULL, return NULL);
	pg = get_order(size);
	res = sbus_alloc_consistent(sdev, PAGE_SIZE * (1 << pg), dma_addr);
	if (res != NULL)
		inc_snd_pages(pg);
	return res;
}

static void snd_free_sbus_pages(struct device *dev, size_t size,
				void *ptr, dma_addr_t dma_addr)
{
	struct sbus_dev *sdev = (struct sbus_dev *)dev;
	int pg;

	if (ptr == NULL)
		return;
	pg = get_order(size);
	dec_snd_pages(pg);
	sbus_free_consistent(sdev, PAGE_SIZE * (1 << pg), ptr, dma_addr);
}

#endif /* CONFIG_SBUS */

/*
 *
 *  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.
 * 
 * Returns zero if the buffer with the given size is allocated successfuly,
 * other a negative value at error.
 */
int snd_dma_alloc_pages(int type, struct device *device, size_t size,
			struct snd_dma_buffer *dmab)
{
	snd_assert(size > 0, return -ENXIO);
	snd_assert(dmab != NULL, 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, (unsigned long)device);
		dmab->addr = 0;
		break;
#ifdef CONFIG_SBUS
	case SNDRV_DMA_TYPE_SBUS:
		dmab->area = snd_malloc_sbus_pages(device, size, &dmab->addr);
		break;
#endif
#ifdef CONFIG_HAS_DMA
	case SNDRV_DMA_TYPE_DEV:
		dmab->area = snd_malloc_dev_pages(device, size, &dmab->addr);
		break;
	case SNDRV_DMA_TYPE_DEV_SG:
		snd_malloc_sgbuf_pages(device, size, dmab, NULL);
		break;
#endif
	default:
		printk(KERN_ERR "snd-malloc: invalid device type %d\n", type);
		dmab->area = NULL;
		dmab->addr = 0;
		return -ENXIO;
	}
	if (! dmab->area)
		return -ENOMEM;