[deliverable/linux.git] / drivers / base / dma-coherent.c

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

struct dma_coherent_mem {
	void		*virt_base;
	dma_addr_t	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	*/
5a0e3ad6	5	#include <linux/slab.h>
ee7e5516	6	#include <linux/kernel.h>
08a999ce	7	#include <linux/module.h>
ee7e5516 DB	8	#include <linux/dma-mapping.h>
	9
	10	struct dma_coherent_mem {
	11	void *virt_base;
ed1d218c	12	dma_addr_t device_base;
ee7e5516 DB	13	int size;
	14	int flags;
	15	unsigned long *bitmap;
	16	};
	17
	18	int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
	19	dma_addr_t device_addr, size_t size, int flags)
	20	{
	21	void __iomem *mem_base = NULL;
	22	int pages = size >> PAGE_SHIFT;
	23	int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
	24
	25	if ((flags & (DMA_MEMORY_MAP \| DMA_MEMORY_IO)) == 0)
	26	goto out;
	27	if (!size)
	28	goto out;
	29	if (dev->dma_mem)
	30	goto out;
	31
	32	/* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
	33
	34	mem_base = ioremap(bus_addr, size);
	35	if (!mem_base)
	36	goto out;
	37
	38	dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
	39	if (!dev->dma_mem)
	40	goto out;
	41	dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
	42	if (!dev->dma_mem->bitmap)
	43	goto free1_out;
	44
	45	dev->dma_mem->virt_base = mem_base;
	46	dev->dma_mem->device_base = device_addr;
	47	dev->dma_mem->size = pages;
	48	dev->dma_mem->flags = flags;
	49
	50	if (flags & DMA_MEMORY_MAP)
	51	return DMA_MEMORY_MAP;
	52
	53	return DMA_MEMORY_IO;
	54
	55	free1_out:
	56	kfree(dev->dma_mem);
	57	out:
	58	if (mem_base)
	59	iounmap(mem_base);
	60	return 0;
	61	}
	62	EXPORT_SYMBOL(dma_declare_coherent_memory);
	63
	64	void dma_release_declared_memory(struct device *dev)
	65	{
	66	struct dma_coherent_mem *mem = dev->dma_mem;
	67
	68	if (!mem)
	69	return;
	70	dev->dma_mem = NULL;
	71	iounmap(mem->virt_base);
	72	kfree(mem->bitmap);
	73	kfree(mem);
	74	}
	75	EXPORT_SYMBOL(dma_release_declared_memory);
	76
77	void dma_mark_declared_memory_occupied(struct device dev,
78	dma_addr_t device_addr, size_t size)
79	{
80	struct dma_coherent_mem *mem = dev->dma_mem;
81	int pos, err;
ee7e5516	82
d2dc1f4a	83	size += device_addr & ~PAGE_MASK;
ee7e5516 DB	84
	85	if (!mem)
	86	return ERR_PTR(-EINVAL);
	87
	88	pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
d2dc1f4a	89	err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
ee7e5516 DB	90	if (err != 0)
	91	return ERR_PTR(err);
	92	return mem->virt_base + (pos << PAGE_SHIFT);
	93	}
	94	EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
	95
b6d4f7e3	96	/**
cb3952bf	97	* dma_alloc_from_coherent() - try to allocate memory from the per-device coherent area
b6d4f7e3 DB	98	*
	99	* @dev: device from which we allocate memory
	100	* @size: size of requested memory area
	101	* @dma_handle: This will be filled with the correct dma handle
	102	* @ret: This pointer will be filled with the virtual address
0609697e	103	* to allocated area.
b6d4f7e3	104	*
cb3952bf	105	* This function should be only called from per-arch dma_alloc_coherent()
b6d4f7e3 DB	106	* to support allocation from per-device coherent memory pools.
	107	*
	108	* Returns 0 if dma_alloc_coherent should continue with allocating from
cb3952bf	109	* generic memory areas, or !0 if dma_alloc_coherent should return @ret.
b6d4f7e3	110	*/
ee7e5516 DB	111	int dma_alloc_from_coherent(struct device *dev, ssize_t size,
	112	dma_addr_t dma_handle, void *ret)
	113	{
eccd83e1	114	struct dma_coherent_mem *mem;
ee7e5516	115	int order = get_order(size);
eccd83e1	116	int pageno;
ee7e5516	117
eccd83e1 AM	118	if (!dev)
	119	return 0;
	120	mem = dev->dma_mem;
	121	if (!mem)
	122	return 0;
0609697e PM	123
	124	*ret = NULL;
	125
cdf57cab	126	if (unlikely(size > (mem->size << PAGE_SHIFT)))
0609697e	127	goto err;
eccd83e1 AM	128
eccd83e1 AM	129	pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
0609697e PM	130	if (unlikely(pageno < 0))
	131	goto err;
	132
	133	/*
	134	* Memory was found in the per-device area.
	135	*/
	136	*dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
	137	*ret = mem->virt_base + (pageno << PAGE_SHIFT);
	138	memset(*ret, 0, size);
	139
eccd83e1	140	return 1;
0609697e PM	141
	142	err:
	143	/*
	144	* In the case where the allocation can not be satisfied from the
	145	* per-device area, try to fall back to generic memory if the
	146	* constraints allow it.
	147	*/
	148	return mem->flags & DMA_MEMORY_EXCLUSIVE;
ee7e5516	149	}
a38409fb	150	EXPORT_SYMBOL(dma_alloc_from_coherent);
ee7e5516	151
b6d4f7e3	152	/**
cb3952bf	153	* dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool
b6d4f7e3 DB	154	* @dev: device from which the memory was allocated
	155	* @order: the order of pages allocated
	156	* @vaddr: virtual address of allocated pages
	157	*
	158	* This checks whether the memory was allocated from the per-device
	159	* coherent memory pool and if so, releases that memory.
	160	*
	161	* Returns 1 if we correctly released the memory, or 0 if
cb3952bf	162	* dma_release_coherent() should proceed with releasing memory from
b6d4f7e3 DB	163	* generic pools.
b6d4f7e3 DB	164	*/
ee7e5516 DB	165	int dma_release_from_coherent(struct device dev, int order, void vaddr)
	166	{
	167	struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
	168
	169	if (mem && vaddr >= mem->virt_base && vaddr <
	170	(mem->virt_base + (mem->size << PAGE_SHIFT))) {
	171	int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
	172
	173	bitmap_release_region(mem->bitmap, page, order);
	174	return 1;
	175	}
	176	return 0;
	177	}
a38409fb	178	EXPORT_SYMBOL(dma_release_from_coherent);