[mirror_ubuntu-bionic-kernel.git] / drivers / base / dma-coherent.c

/*
 * Coherent per-device memory handling.
 * Borrowed from i386
 */
#include <linux/io.h>
#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;
	unsigned long	pfn_base;
	int		size;
	int		flags;
	unsigned long	*bitmap;
	spinlock_t	spinlock;
	bool		use_dev_dma_pfn_offset;
};

static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;

static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev)
{
	if (dev && dev->dma_mem)
		return dev->dma_mem;
	return dma_coherent_default_memory;
}

static inline dma_addr_t dma_get_device_base(struct device *dev,
					     struct dma_coherent_mem * mem)
{
	if (mem->use_dev_dma_pfn_offset)
		return (mem->pfn_base - dev->dma_pfn_offset) << PAGE_SHIFT;
	else
		return mem->device_base;
}

static bool dma_init_coherent_memory(
	phys_addr_t phys_addr, dma_addr_t device_addr, size_t size, int flags,
	struct dma_coherent_mem **mem)
{
	struct dma_coherent_mem *dma_mem = NULL;
	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 (flags & DMA_MEMORY_MAP)
		mem_base = memremap(phys_addr, size, MEMREMAP_WC);
	else
		mem_base = ioremap(phys_addr, size);
	if (!mem_base)
		goto out;

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

	dma_mem->virt_base = mem_base;
	dma_mem->device_base = device_addr;
	dma_mem->pfn_base = PFN_DOWN(phys_addr);
	dma_mem->size = pages;
	dma_mem->flags = flags;
	spin_lock_init(&dma_mem->spinlock);

	*mem = dma_mem;
	return true;

out:
	kfree(dma_mem);
	if (mem_base) {
		if (flags & DMA_MEMORY_MAP)
			memunmap(mem_base);
		else
			iounmap(mem_base);
	}
	return false;
}

static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
{
	if (!mem)
		return;

	if (mem->flags & DMA_MEMORY_MAP)
		memunmap(mem->virt_base);
	else
		iounmap(mem->virt_base);
	kfree(mem->bitmap);
	kfree(mem);
}

static int dma_assign_coherent_memory(struct device *dev,
				      struct dma_coherent_mem *mem)
{
	if (!dev)
		return -ENODEV;

	if (dev->dma_mem)
		return -EBUSY;

	dev->dma_mem = mem;
	/* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */

	return 0;
}

int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
				dma_addr_t device_addr, size_t size, int flags)
{
	struct dma_coherent_mem *mem;

	if (!dma_init_coherent_memory(phys_addr, device_addr, size, flags,
				      &mem))
		return 0;

	if (dma_assign_coherent_memory(dev, mem) == 0)
		return flags & DMA_MEMORY_MAP ? DMA_MEMORY_MAP : DMA_MEMORY_IO;

	dma_release_coherent_memory(mem);
	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;
	dma_release_coherent_memory(mem);
	dev->dma_mem = NULL;
}
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;
	unsigned long flags;
	int pos, err;

	size += device_addr & ~PAGE_MASK;

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

	spin_lock_irqsave(&mem->spinlock, flags);
	pos = PFN_DOWN(device_addr - dma_get_device_base(dev, mem));
	err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
	spin_unlock_irqrestore(&mem->spinlock, flags);

	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 = dev_get_coherent_memory(dev);
	int order = get_order(size);
	unsigned long flags;
	int pageno;
	int dma_memory_map;

	if (!mem)
		return 0;

	*ret = NULL;
	spin_lock_irqsave(&mem->spinlock, flags);

	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 = dma_get_device_base(dev, mem) + (pageno << PAGE_SHIFT);
	*ret = mem->virt_base + (pageno << PAGE_SHIFT);
	dma_memory_map = (mem->flags & DMA_MEMORY_MAP);
	spin_unlock_irqrestore(&mem->spinlock, flags);
	if (dma_memory_map)
		memset(*ret, 0, size);
	else
		memset_io(*ret, 0, size);

	return 1;

err:
	spin_unlock_irqrestore(&mem->spinlock, flags);
	/*
	 * 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_get_coherent_memory(dev);

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

		spin_lock_irqsave(&mem->spinlock, flags);
		bitmap_release_region(mem->bitmap, page, order);
		spin_unlock_irqrestore(&mem->spinlock, flags);
		return 1;
	}
	return 0;
}
EXPORT_SYMBOL(dma_release_from_coherent);

/**
 * dma_mmap_from_coherent() - try to mmap the memory allocated from
 * per-device coherent memory pool to userspace
 * @dev:	device from which the memory was allocated
 * @vma:	vm_area for the userspace memory
 * @vaddr:	cpu address returned by dma_alloc_from_coherent
 * @size:	size of the memory buffer allocated by dma_alloc_from_coherent
 * @ret:	result from remap_pfn_range()
 *
 * This checks whether the memory was allocated from the per-device
 * coherent memory pool and if so, maps that memory to the provided vma.
 *
 * Returns 1 if we correctly mapped the memory, or 0 if the caller should
 * proceed with mapping memory from generic pools.
 */
int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma,
			   void *vaddr, size_t size, int *ret)
{
	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);

	if (mem && vaddr >= mem->virt_base && vaddr + size <=
		   (mem->virt_base + (mem->size << PAGE_SHIFT))) {
		unsigned long off = vma->vm_pgoff;
		int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
		int user_count = vma_pages(vma);
		int count = PAGE_ALIGN(size) >> PAGE_SHIFT;

		*ret = -ENXIO;
		if (off < count && user_count <= count - off) {
			unsigned long pfn = mem->pfn_base + start + off;
			*ret = remap_pfn_range(vma, vma->vm_start, pfn,
					       user_count << PAGE_SHIFT,
					       vma->vm_page_prot);
		}
		return 1;
	}
	return 0;
}
EXPORT_SYMBOL(dma_mmap_from_coherent);

/*
 * Support for reserved memory regions defined in device tree
 */
#ifdef CONFIG_OF_RESERVED_MEM
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/of_reserved_mem.h>

static struct reserved_mem *dma_reserved_default_memory __initdata;

static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
{
	struct dma_coherent_mem *mem = rmem->priv;

	if (!mem &&
	    !dma_init_coherent_memory(rmem->base, rmem->base, rmem->size,
				      DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE,
				      &mem)) {
		pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
			&rmem->base, (unsigned long)rmem->size / SZ_1M);
		return -ENODEV;
	}
	mem->use_dev_dma_pfn_offset = true;
	rmem->priv = mem;
	dma_assign_coherent_memory(dev, mem);
	return 0;
}

static void rmem_dma_device_release(struct reserved_mem *rmem,
				    struct device *dev)
{
	if (dev)
		dev->dma_mem = NULL;
}

static const struct reserved_mem_ops rmem_dma_ops = {
	.device_init	= rmem_dma_device_init,
	.device_release	= rmem_dma_device_release,
};

static int __init rmem_dma_setup(struct reserved_mem *rmem)
{
	unsigned long node = rmem->fdt_node;

	if (of_get_flat_dt_prop(node, "reusable", NULL))
		return -EINVAL;

#ifdef CONFIG_ARM
	if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
		pr_err("Reserved memory: regions without no-map are not yet supported\n");
		return -EINVAL;
	}

	if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) {
		WARN(dma_reserved_default_memory,
		     "Reserved memory: region for default DMA coherent area is redefined\n");
		dma_reserved_default_memory = rmem;
	}
#endif

	rmem->ops = &rmem_dma_ops;
	pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
		&rmem->base, (unsigned long)rmem->size / SZ_1M);
	return 0;
}

static int __init dma_init_reserved_memory(void)
{
	const struct reserved_mem_ops *ops;
	int ret;

	if (!dma_reserved_default_memory)
		return -ENOMEM;

	ops = dma_reserved_default_memory->ops;

	/*
	 * We rely on rmem_dma_device_init() does not propagate error of
	 * dma_assign_coherent_memory() for "NULL" device.
	 */
	ret = ops->device_init(dma_reserved_default_memory, NULL);

	if (!ret) {
		dma_coherent_default_memory = dma_reserved_default_memory->priv;
		pr_info("DMA: default coherent area is set\n");
	}

	return ret;
}

core_initcall(dma_init_reserved_memory);

RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
#endif
Commit	Line	Data
ee7e5516 DES	1	/*
	2	* Coherent per-device memory handling.
	3	* Borrowed from i386
	4	*/
6b03ae0d	5	#include <linux/io.h>
5a0e3ad6	6	#include <linux/slab.h>
ee7e5516	7	#include <linux/kernel.h>
08a999ce	8	#include <linux/module.h>
ee7e5516 DES	9	#include <linux/dma-mapping.h>
	10
	11	struct dma_coherent_mem {
	12	void *virt_base;
ed1d218c	13	dma_addr_t device_base;
88a984ba	14	unsigned long pfn_base;
ee7e5516 DES	15	int size;
	16	int flags;
	17	unsigned long *bitmap;
7bfa5ab6	18	spinlock_t spinlock;
c41f9ea9	19	bool use_dev_dma_pfn_offset;
ee7e5516 DES	20	};
ee7e5516 DES	21
93228b44 VM	22	static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
	23
	24	static inline struct dma_coherent_mem dev_get_coherent_memory(struct device dev)
	25	{
	26	if (dev && dev->dma_mem)
	27	return dev->dma_mem;
	28	return dma_coherent_default_memory;
	29	}
	30
c41f9ea9 VM	31	static inline dma_addr_t dma_get_device_base(struct device *dev,
	32	struct dma_coherent_mem * mem)
	33	{
	34	if (mem->use_dev_dma_pfn_offset)
	35	return (mem->pfn_base - dev->dma_pfn_offset) << PAGE_SHIFT;
	36	else
	37	return mem->device_base;
	38	}
	39
9e5b3d6f MN	40	static bool dma_init_coherent_memory(
	41	phys_addr_t phys_addr, dma_addr_t device_addr, size_t size, int flags,
	42	struct dma_coherent_mem **mem)
ee7e5516	43	{
7bfa5ab6	44	struct dma_coherent_mem *dma_mem = NULL;
ee7e5516 DES	45	void __iomem *mem_base = NULL;
	46	int pages = size >> PAGE_SHIFT;
	47	int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
	48
	49	if ((flags & (DMA_MEMORY_MAP \| DMA_MEMORY_IO)) == 0)
	50	goto out;
	51	if (!size)
	52	goto out;
ee7e5516	53
6b03ae0d BS	54	if (flags & DMA_MEMORY_MAP)
	55	mem_base = memremap(phys_addr, size, MEMREMAP_WC);
	56	else
	57	mem_base = ioremap(phys_addr, size);
ee7e5516 DES	58	if (!mem_base)
	59	goto out;
	60
7bfa5ab6 MS	61	dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
7bfa5ab6 MS	62	if (!dma_mem)
ee7e5516	63	goto out;
7bfa5ab6 MS	64	dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
	65	if (!dma_mem->bitmap)
	66	goto out;
	67
	68	dma_mem->virt_base = mem_base;
	69	dma_mem->device_base = device_addr;
	70	dma_mem->pfn_base = PFN_DOWN(phys_addr);
	71	dma_mem->size = pages;
	72	dma_mem->flags = flags;
	73	spin_lock_init(&dma_mem->spinlock);
ee7e5516	74
7bfa5ab6	75	*mem = dma_mem;
9e5b3d6f	76	return true;
ee7e5516	77
7bfa5ab6 MS	78	out:
7bfa5ab6 MS	79	kfree(dma_mem);
6b03ae0d BS	80	if (mem_base) {
	81	if (flags & DMA_MEMORY_MAP)
	82	memunmap(mem_base);
	83	else
	84	iounmap(mem_base);
	85	}
9e5b3d6f	86	return false;
ee7e5516	87	}
7bfa5ab6 MS	88
	89	static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
	90	{
	91	if (!mem)
	92	return;
6b03ae0d BS	93
	94	if (mem->flags & DMA_MEMORY_MAP)
	95	memunmap(mem->virt_base);
	96	else
	97	iounmap(mem->virt_base);
7bfa5ab6 MS	98	kfree(mem->bitmap);
	99	kfree(mem);
	100	}
	101
	102	static int dma_assign_coherent_memory(struct device *dev,
	103	struct dma_coherent_mem *mem)
	104	{
93228b44 VM	105	if (!dev)
	106	return -ENODEV;
	107
7bfa5ab6 MS	108	if (dev->dma_mem)
	109	return -EBUSY;
	110
	111	dev->dma_mem = mem;
	112	/* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
	113
	114	return 0;
	115	}
	116
	117	int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
	118	dma_addr_t device_addr, size_t size, int flags)
	119	{
	120	struct dma_coherent_mem *mem;
7bfa5ab6	121
9e5b3d6f MN	122	if (!dma_init_coherent_memory(phys_addr, device_addr, size, flags,
9e5b3d6f MN	123	&mem))
7bfa5ab6 MS	124	return 0;
	125
	126	if (dma_assign_coherent_memory(dev, mem) == 0)
9e5b3d6f	127	return flags & DMA_MEMORY_MAP ? DMA_MEMORY_MAP : DMA_MEMORY_IO;
7bfa5ab6 MS	128
	129	dma_release_coherent_memory(mem);
	130	return 0;
	131	}
ee7e5516 DES	132	EXPORT_SYMBOL(dma_declare_coherent_memory);
	133
	134	void dma_release_declared_memory(struct device *dev)
	135	{
	136	struct dma_coherent_mem *mem = dev->dma_mem;
	137
	138	if (!mem)
	139	return;
7bfa5ab6	140	dma_release_coherent_memory(mem);
ee7e5516	141	dev->dma_mem = NULL;
ee7e5516 DES	142	}
	143	EXPORT_SYMBOL(dma_release_declared_memory);
	144
	145	void dma_mark_declared_memory_occupied(struct device dev,
	146	dma_addr_t device_addr, size_t size)
	147	{
	148	struct dma_coherent_mem *mem = dev->dma_mem;
7bfa5ab6	149	unsigned long flags;
ee7e5516	150	int pos, err;
ee7e5516	151
d2dc1f4a	152	size += device_addr & ~PAGE_MASK;
ee7e5516 DES	153
	154	if (!mem)
	155	return ERR_PTR(-EINVAL);
	156
7bfa5ab6	157	spin_lock_irqsave(&mem->spinlock, flags);
c41f9ea9	158	pos = PFN_DOWN(device_addr - dma_get_device_base(dev, mem));
d2dc1f4a	159	err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
7bfa5ab6 MS	160	spin_unlock_irqrestore(&mem->spinlock, flags);
7bfa5ab6 MS	161
ee7e5516 DES	162	if (err != 0)
	163	return ERR_PTR(err);
	164	return mem->virt_base + (pos << PAGE_SHIFT);
	165	}
	166	EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
	167
b6d4f7e3	168	/**
cb3952bf	169	* dma_alloc_from_coherent() - try to allocate memory from the per-device coherent area
b6d4f7e3 DES	170	*
	171	* @dev: device from which we allocate memory
	172	* @size: size of requested memory area
	173	* @dma_handle: This will be filled with the correct dma handle
	174	* @ret: This pointer will be filled with the virtual address
0609697e	175	* to allocated area.
b6d4f7e3	176	*
cb3952bf	177	* This function should be only called from per-arch dma_alloc_coherent()
b6d4f7e3 DES	178	* to support allocation from per-device coherent memory pools.
	179	*
	180	* Returns 0 if dma_alloc_coherent should continue with allocating from
cb3952bf	181	* generic memory areas, or !0 if dma_alloc_coherent should return @ret.
b6d4f7e3	182	*/
ee7e5516 DES	183	int dma_alloc_from_coherent(struct device *dev, ssize_t size,
	184	dma_addr_t dma_handle, void *ret)
	185	{
93228b44	186	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
ee7e5516	187	int order = get_order(size);
7bfa5ab6	188	unsigned long flags;
eccd83e1	189	int pageno;
dd01c75f	190	int dma_memory_map;
ee7e5516	191
eccd83e1 AM	192	if (!mem)
eccd83e1 AM	193	return 0;
0609697e PM	194
0609697e PM	195	*ret = NULL;
7bfa5ab6	196	spin_lock_irqsave(&mem->spinlock, flags);
0609697e	197
cdf57cab	198	if (unlikely(size > (mem->size << PAGE_SHIFT)))
0609697e	199	goto err;
eccd83e1 AM	200
eccd83e1 AM	201	pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
0609697e PM	202	if (unlikely(pageno < 0))
	203	goto err;
	204
	205	/*
	206	* Memory was found in the per-device area.
	207	*/
c41f9ea9	208	*dma_handle = dma_get_device_base(dev, mem) + (pageno << PAGE_SHIFT);
0609697e	209	*ret = mem->virt_base + (pageno << PAGE_SHIFT);
dd01c75f BH	210	dma_memory_map = (mem->flags & DMA_MEMORY_MAP);
	211	spin_unlock_irqrestore(&mem->spinlock, flags);
	212	if (dma_memory_map)
20d7a35b BS	213	memset(*ret, 0, size);
	214	else
	215	memset_io(*ret, 0, size);
0609697e	216
eccd83e1	217	return 1;
0609697e PM	218
0609697e PM	219	err:
7bfa5ab6	220	spin_unlock_irqrestore(&mem->spinlock, flags);
0609697e PM	221	/*
	222	* In the case where the allocation can not be satisfied from the
	223	* per-device area, try to fall back to generic memory if the
	224	* constraints allow it.
	225	*/
	226	return mem->flags & DMA_MEMORY_EXCLUSIVE;
ee7e5516	227	}
a38409fb	228	EXPORT_SYMBOL(dma_alloc_from_coherent);
ee7e5516	229
b6d4f7e3	230	/**
cb3952bf	231	* dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool
b6d4f7e3 DES	232	* @dev: device from which the memory was allocated
	233	* @order: the order of pages allocated
	234	* @vaddr: virtual address of allocated pages
	235	*
	236	* This checks whether the memory was allocated from the per-device
	237	* coherent memory pool and if so, releases that memory.
	238	*
	239	* Returns 1 if we correctly released the memory, or 0 if
cb3952bf	240	* dma_release_coherent() should proceed with releasing memory from
b6d4f7e3 DES	241	* generic pools.
b6d4f7e3 DES	242	*/
ee7e5516 DES	243	int dma_release_from_coherent(struct device dev, int order, void vaddr)
ee7e5516 DES	244	{
93228b44	245	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
ee7e5516 DES	246
	247	if (mem && vaddr >= mem->virt_base && vaddr <
	248	(mem->virt_base + (mem->size << PAGE_SHIFT))) {
	249	int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
7bfa5ab6	250	unsigned long flags;
ee7e5516	251
7bfa5ab6	252	spin_lock_irqsave(&mem->spinlock, flags);
ee7e5516	253	bitmap_release_region(mem->bitmap, page, order);
7bfa5ab6	254	spin_unlock_irqrestore(&mem->spinlock, flags);
ee7e5516 DES	255	return 1;
	256	}
	257	return 0;
	258	}
a38409fb	259	EXPORT_SYMBOL(dma_release_from_coherent);
bca0fa5f MS	260
	261	/**
	262	* dma_mmap_from_coherent() - try to mmap the memory allocated from
	263	* per-device coherent memory pool to userspace
	264	* @dev: device from which the memory was allocated
	265	* @vma: vm_area for the userspace memory
	266	* @vaddr: cpu address returned by dma_alloc_from_coherent
	267	* @size: size of the memory buffer allocated by dma_alloc_from_coherent
6e7b4a59	268	* @ret: result from remap_pfn_range()
bca0fa5f MS	269	*
	270	* This checks whether the memory was allocated from the per-device
	271	* coherent memory pool and if so, maps that memory to the provided vma.
	272	*
ba4d93bc LP	273	* Returns 1 if we correctly mapped the memory, or 0 if the caller should
ba4d93bc LP	274	* proceed with mapping memory from generic pools.
bca0fa5f MS	275	*/
	276	int dma_mmap_from_coherent(struct device dev, struct vm_area_struct vma,
	277	void vaddr, size_t size, int ret)
	278	{
93228b44	279	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
bca0fa5f MS	280
	281	if (mem && vaddr >= mem->virt_base && vaddr + size <=
	282	(mem->virt_base + (mem->size << PAGE_SHIFT))) {
	283	unsigned long off = vma->vm_pgoff;
	284	int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
e688f144	285	int user_count = vma_pages(vma);
9ca5d4fd	286	int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
bca0fa5f MS	287
	288	*ret = -ENXIO;
	289	if (off < count && user_count <= count - off) {
88a984ba	290	unsigned long pfn = mem->pfn_base + start + off;
bca0fa5f MS	291	*ret = remap_pfn_range(vma, vma->vm_start, pfn,
	292	user_count << PAGE_SHIFT,
	293	vma->vm_page_prot);
	294	}
	295	return 1;
	296	}
	297	return 0;
	298	}
	299	EXPORT_SYMBOL(dma_mmap_from_coherent);
7bfa5ab6 MS	300
	301	/*
	302	* Support for reserved memory regions defined in device tree
	303	*/
	304	#ifdef CONFIG_OF_RESERVED_MEM
	305	#include <linux/of.h>
	306	#include <linux/of_fdt.h>
	307	#include <linux/of_reserved_mem.h>
	308
93228b44 VM	309	static struct reserved_mem *dma_reserved_default_memory __initdata;
93228b44 VM	310
7bfa5ab6 MS	311	static int rmem_dma_device_init(struct reserved_mem rmem, struct device dev)
	312	{
	313	struct dma_coherent_mem *mem = rmem->priv;
	314
	315	if (!mem &&
9e5b3d6f MN	316	!dma_init_coherent_memory(rmem->base, rmem->base, rmem->size,
	317	DMA_MEMORY_MAP \| DMA_MEMORY_EXCLUSIVE,
	318	&mem)) {
7bfa5ab6 MS	319	pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
	320	&rmem->base, (unsigned long)rmem->size / SZ_1M);
	321	return -ENODEV;
	322	}
c41f9ea9	323	mem->use_dev_dma_pfn_offset = true;
7bfa5ab6 MS	324	rmem->priv = mem;
	325	dma_assign_coherent_memory(dev, mem);
	326	return 0;
	327	}
	328
	329	static void rmem_dma_device_release(struct reserved_mem *rmem,
	330	struct device *dev)
	331	{
93228b44 VM	332	if (dev)
93228b44 VM	333	dev->dma_mem = NULL;
7bfa5ab6 MS	334	}
	335
	336	static const struct reserved_mem_ops rmem_dma_ops = {
	337	.device_init = rmem_dma_device_init,
	338	.device_release = rmem_dma_device_release,
	339	};
	340
	341	static int __init rmem_dma_setup(struct reserved_mem *rmem)
	342	{
	343	unsigned long node = rmem->fdt_node;
	344
	345	if (of_get_flat_dt_prop(node, "reusable", NULL))
	346	return -EINVAL;
	347
	348	#ifdef CONFIG_ARM
	349	if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
	350	pr_err("Reserved memory: regions without no-map are not yet supported\n");
	351	return -EINVAL;
	352	}
93228b44 VM	353
	354	if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) {
	355	WARN(dma_reserved_default_memory,
	356	"Reserved memory: region for default DMA coherent area is redefined\n");
	357	dma_reserved_default_memory = rmem;
	358	}
7bfa5ab6 MS	359	#endif
	360
	361	rmem->ops = &rmem_dma_ops;
	362	pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
	363	&rmem->base, (unsigned long)rmem->size / SZ_1M);
	364	return 0;
	365	}
93228b44 VM	366
	367	static int __init dma_init_reserved_memory(void)
	368	{
	369	const struct reserved_mem_ops *ops;
	370	int ret;
	371
	372	if (!dma_reserved_default_memory)
	373	return -ENOMEM;
	374
	375	ops = dma_reserved_default_memory->ops;
	376
	377	/*
	378	* We rely on rmem_dma_device_init() does not propagate error of
	379	* dma_assign_coherent_memory() for "NULL" device.
	380	*/
	381	ret = ops->device_init(dma_reserved_default_memory, NULL);
	382
	383	if (!ret) {
	384	dma_coherent_default_memory = dma_reserved_default_memory->priv;
	385	pr_info("DMA: default coherent area is set\n");
	386	}
	387
	388	return ret;
	389	}
	390
	391	core_initcall(dma_init_reserved_memory);
	392
7bfa5ab6 MS	393	RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
7bfa5ab6 MS	394	#endif