[linux-2.6-block.git] / kernel / dma-coherent.c

/*
 * Coherent per-device memory handling.
 * Borrowed from i386
 */
#include <linux/kernel.h>
#include <linux/dma-mapping.h>

struct dma_coherent_mem {
	void		*virt_base;
	u32		device_base;
	int		size;
	int		flags;
	unsigned long	*bitmap;
};

int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
				dma_addr_t device_addr, size_t size, int flags)
{
	void __iomem *mem_base = NULL;
	int pages = size >> PAGE_SHIFT;
	int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);

	if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
		goto out;
	if (!size)
		goto out;
	if (dev->dma_mem)
		goto out;

	/* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */

	mem_base = ioremap(bus_addr, size);
	if (!mem_base)
		goto out;

	dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
	if (!dev->dma_mem)
		goto out;
	dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
	if (!dev->dma_mem->bitmap)
		goto free1_out;

	dev->dma_mem->virt_base = mem_base;
	dev->dma_mem->device_base = device_addr;
	dev->dma_mem->size = pages;
	dev->dma_mem->flags = flags;

	if (flags & DMA_MEMORY_MAP)
		return DMA_MEMORY_MAP;

	return DMA_MEMORY_IO;

 free1_out:
	kfree(dev->dma_mem);
 out:
	if (mem_base)
		iounmap(mem_base);
	return 0;
}
EXPORT_SYMBOL(dma_declare_coherent_memory);

void dma_release_declared_memory(struct device *dev)
{
	struct dma_coherent_mem *mem = dev->dma_mem;

	if (!mem)
		return;
	dev->dma_mem = NULL;
	iounmap(mem->virt_base);
	kfree(mem->bitmap);
	kfree(mem);
}
EXPORT_SYMBOL(dma_release_declared_memory);

void *dma_mark_declared_memory_occupied(struct device *dev,
					dma_addr_t device_addr, size_t size)
{
	struct dma_coherent_mem *mem = dev->dma_mem;
	int pos, err;

	size += device_addr & ~PAGE_MASK;

	if (!mem)
		return ERR_PTR(-EINVAL);

	pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
	err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
	if (err != 0)
		return ERR_PTR(err);
	return mem->virt_base + (pos << PAGE_SHIFT);
}
EXPORT_SYMBOL(dma_mark_declared_memory_occupied);

/**
 * dma_alloc_from_coherent() - try to allocate memory from the per-device coherent area
 *
 * @dev:	device from which we allocate memory
 * @size:	size of requested memory area
 * @dma_handle:	This will be filled with the correct dma handle
 * @ret:	This pointer will be filled with the virtual address
 *		to allocated area.
 *
 * This function should be only called from per-arch dma_alloc_coherent()
 * to support allocation from per-device coherent memory pools.
 *
 * Returns 0 if dma_alloc_coherent should continue with allocating from
 * generic memory areas, or !0 if dma_alloc_coherent should return @ret.
 */
int dma_alloc_from_coherent(struct device *dev, ssize_t size,
				       dma_addr_t *dma_handle, void **ret)
{
	struct dma_coherent_mem *mem;
	int order = get_order(size);
	int pageno;

	if (!dev)
		return 0;
	mem = dev->dma_mem;
	if (!mem)
		return 0;

	*ret = NULL;

	if (unlikely(size > (mem->size << PAGE_SHIFT)))
		goto err;

	pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
	if (unlikely(pageno < 0))
		goto err;

	/*
	 * Memory was found in the per-device area.
	 */
	*dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
	*ret = mem->virt_base + (pageno << PAGE_SHIFT);
	memset(*ret, 0, size);

	return 1;

err:
	/*
	 * In the case where the allocation can not be satisfied from the
	 * per-device area, try to fall back to generic memory if the
	 * constraints allow it.
	 */
	return mem->flags & DMA_MEMORY_EXCLUSIVE;
}
EXPORT_SYMBOL(dma_alloc_from_coherent);

/**
 * dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool
 * @dev:	device from which the memory was allocated
 * @order:	the order of pages allocated
 * @vaddr:	virtual address of allocated pages
 *
 * This checks whether the memory was allocated from the per-device
 * coherent memory pool and if so, releases that memory.
 *
 * Returns 1 if we correctly released the memory, or 0 if
 * dma_release_coherent() should proceed with releasing memory from
 * generic pools.
 */
int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
{
	struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;

	if (mem && vaddr >= mem->virt_base && vaddr <
		   (mem->virt_base + (mem->size << PAGE_SHIFT))) {
		int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;

		bitmap_release_region(mem->bitmap, page, order);
		return 1;
	}
	return 0;
}
EXPORT_SYMBOL(dma_release_from_coherent);
Commit	Line	Data
ee7e5516 DB	1	/*
	2	* Coherent per-device memory handling.
	3	* Borrowed from i386
	4	*/
	5	#include <linux/kernel.h>
	6	#include <linux/dma-mapping.h>
	7
	8	struct dma_coherent_mem {
	9	void *virt_base;
	10	u32 device_base;
	11	int size;
	12	int flags;
	13	unsigned long *bitmap;
	14	};
	15
	16	int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
	17	dma_addr_t device_addr, size_t size, int flags)
	18	{
	19	void __iomem *mem_base = NULL;
	20	int pages = size >> PAGE_SHIFT;
	21	int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
	22
	23	if ((flags & (DMA_MEMORY_MAP \| DMA_MEMORY_IO)) == 0)
	24	goto out;
	25	if (!size)
	26	goto out;
	27	if (dev->dma_mem)
	28	goto out;
	29
	30	/* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
	31
	32	mem_base = ioremap(bus_addr, size);
	33	if (!mem_base)
	34	goto out;
	35
	36	dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
	37	if (!dev->dma_mem)
	38	goto out;
	39	dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
	40	if (!dev->dma_mem->bitmap)
	41	goto free1_out;
	42
	43	dev->dma_mem->virt_base = mem_base;
	44	dev->dma_mem->device_base = device_addr;
	45	dev->dma_mem->size = pages;
	46	dev->dma_mem->flags = flags;
	47
	48	if (flags & DMA_MEMORY_MAP)
	49	return DMA_MEMORY_MAP;
	50
	51	return DMA_MEMORY_IO;
	52
	53	free1_out:
	54	kfree(dev->dma_mem);
	55	out:
	56	if (mem_base)
	57	iounmap(mem_base);
	58	return 0;
	59	}
	60	EXPORT_SYMBOL(dma_declare_coherent_memory);
	61
	62	void dma_release_declared_memory(struct device *dev)
	63	{
	64	struct dma_coherent_mem *mem = dev->dma_mem;
65
66	if (!mem)
67	return;
68	dev->dma_mem = NULL;
69	iounmap(mem->virt_base);
70	kfree(mem->bitmap);
71	kfree(mem);
72	}
73	EXPORT_SYMBOL(dma_release_declared_memory);
74
75	void dma_mark_declared_memory_occupied(struct device dev,
76	dma_addr_t device_addr, size_t size)
77	{
78	struct dma_coherent_mem *mem = dev->dma_mem;
79	int pos, err;
ee7e5516	80
d2dc1f4a	81	size += device_addr & ~PAGE_MASK;
ee7e5516 DB	82
	83	if (!mem)
	84	return ERR_PTR(-EINVAL);
	85
	86	pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
d2dc1f4a	87	err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
ee7e5516 DB	88	if (err != 0)
	89	return ERR_PTR(err);
	90	return mem->virt_base + (pos << PAGE_SHIFT);
	91	}
	92	EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
	93
b6d4f7e3	94	/**
cb3952bf	95	* dma_alloc_from_coherent() - try to allocate memory from the per-device coherent area
b6d4f7e3 DB	96	*
	97	* @dev: device from which we allocate memory
	98	* @size: size of requested memory area
	99	* @dma_handle: This will be filled with the correct dma handle
	100	* @ret: This pointer will be filled with the virtual address
0609697e	101	* to allocated area.
b6d4f7e3	102	*
cb3952bf	103	* This function should be only called from per-arch dma_alloc_coherent()
b6d4f7e3 DB	104	* to support allocation from per-device coherent memory pools.
	105	*
	106	* Returns 0 if dma_alloc_coherent should continue with allocating from
cb3952bf	107	* generic memory areas, or !0 if dma_alloc_coherent should return @ret.
b6d4f7e3	108	*/
ee7e5516 DB	109	int dma_alloc_from_coherent(struct device *dev, ssize_t size,
	110	dma_addr_t dma_handle, void *ret)
	111	{
eccd83e1	112	struct dma_coherent_mem *mem;
ee7e5516	113	int order = get_order(size);
eccd83e1	114	int pageno;
ee7e5516	115
eccd83e1 AM	116	if (!dev)
	117	return 0;
	118	mem = dev->dma_mem;
	119	if (!mem)
	120	return 0;
0609697e PM	121
	122	*ret = NULL;
	123
cdf57cab	124	if (unlikely(size > (mem->size << PAGE_SHIFT)))
0609697e	125	goto err;
eccd83e1 AM	126
eccd83e1 AM	127	pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
0609697e PM	128	if (unlikely(pageno < 0))
	129	goto err;
	130
	131	/*
	132	* Memory was found in the per-device area.
	133	*/
	134	*dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
	135	*ret = mem->virt_base + (pageno << PAGE_SHIFT);
	136	memset(*ret, 0, size);
	137
eccd83e1	138	return 1;
0609697e PM	139
	140	err:
	141	/*
	142	* In the case where the allocation can not be satisfied from the
	143	* per-device area, try to fall back to generic memory if the
	144	* constraints allow it.
	145	*/
	146	return mem->flags & DMA_MEMORY_EXCLUSIVE;
ee7e5516	147	}
a38409fb	148	EXPORT_SYMBOL(dma_alloc_from_coherent);
ee7e5516	149
b6d4f7e3	150	/**
cb3952bf	151	* dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool
b6d4f7e3 DB	152	* @dev: device from which the memory was allocated
	153	* @order: the order of pages allocated
	154	* @vaddr: virtual address of allocated pages
	155	*
	156	* This checks whether the memory was allocated from the per-device
	157	* coherent memory pool and if so, releases that memory.
	158	*
	159	* Returns 1 if we correctly released the memory, or 0 if
cb3952bf	160	* dma_release_coherent() should proceed with releasing memory from
b6d4f7e3 DB	161	* generic pools.
b6d4f7e3 DB	162	*/
ee7e5516 DB	163	int dma_release_from_coherent(struct device dev, int order, void vaddr)
	164	{
	165	struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
	166
	167	if (mem && vaddr >= mem->virt_base && vaddr <
	168	(mem->virt_base + (mem->size << PAGE_SHIFT))) {
	169	int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
	170
	171	bitmap_release_region(mem->bitmap, page, order);
	172	return 1;
	173	}
	174	return 0;
	175	}
a38409fb	176	EXPORT_SYMBOL(dma_release_from_coherent);