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

// SPDX-License-Identifier: GPL-2.0
/*
 * 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-direct.h>
#include <linux/dma-map-ops.h>

struct dma_coherent_mem {
	void		*virt_base;
	dma_addr_t	device_base;
	unsigned long	pfn_base;
	int		size;
	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 NULL;
}

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 phys_to_dma(dev, PFN_PHYS(mem->pfn_base));
	return mem->device_base;
}

static int dma_init_coherent_memory(phys_addr_t phys_addr,
		dma_addr_t device_addr, size_t size,
		struct dma_coherent_mem **mem)
{
	struct dma_coherent_mem *dma_mem = NULL;
	void *mem_base = NULL;
	int pages = size >> PAGE_SHIFT;
	int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
	int ret;

	if (!size) {
		ret = -EINVAL;
		goto out;
	}

	mem_base = memremap(phys_addr, size, MEMREMAP_WC);
	if (!mem_base) {
		ret = -EINVAL;
		goto out;
	}
	dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
	if (!dma_mem) {
		ret = -ENOMEM;
		goto out;
	}
	dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
	if (!dma_mem->bitmap) {
		ret = -ENOMEM;
		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;
	spin_lock_init(&dma_mem->spinlock);

	*mem = dma_mem;
	return 0;

out:
	kfree(dma_mem);
	if (mem_base)
		memunmap(mem_base);
	return ret;
}

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

	memunmap(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;
	return 0;
}

/*
 * Declare a region of memory to be handed out by dma_alloc_coherent() when it
 * is asked for coherent memory for this device.  This shall only be used
 * from platform code, usually based on the device tree description.
 * 
 * phys_addr is the CPU physical address to which the memory is currently
 * assigned (this will be ioremapped so the CPU can access the region).
 *
 * device_addr is the DMA address the device needs to be programmed with to
 * actually address this memory (this will be handed out as the dma_addr_t in
 * dma_alloc_coherent()).
 *
 * size is the size of the area (must be a multiple of PAGE_SIZE).
 *
 * As a simplification for the platforms, only *one* such region of memory may
 * be declared per device.
 */
int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
				dma_addr_t device_addr, size_t size)
{
	struct dma_coherent_mem *mem;
	int ret;

	ret = dma_init_coherent_memory(phys_addr, device_addr, size, &mem);
	if (ret)
		return ret;

	ret = dma_assign_coherent_memory(dev, mem);
	if (ret)
		dma_release_coherent_memory(mem);
	return ret;
}

static void *__dma_alloc_from_coherent(struct device *dev,
				       struct dma_coherent_mem *mem,
				       ssize_t size, dma_addr_t *dma_handle)
{
	int order = get_order(size);
	unsigned long flags;
	int pageno;
	void *ret;

	spin_lock_irqsave(&mem->spinlock, flags);

	if (unlikely(size > ((dma_addr_t)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 coherent area.
	 */
	*dma_handle = dma_get_device_base(dev, mem) +
			((dma_addr_t)pageno << PAGE_SHIFT);
	ret = mem->virt_base + ((dma_addr_t)pageno << PAGE_SHIFT);
	spin_unlock_irqrestore(&mem->spinlock, flags);
	memset(ret, 0, size);
	return ret;
err:
	spin_unlock_irqrestore(&mem->spinlock, flags);
	return NULL;
}

/**
 * dma_alloc_from_dev_coherent() - allocate memory from device coherent pool
 * @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_dev_coherent(struct device *dev, ssize_t size,
		dma_addr_t *dma_handle, void **ret)
{
	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);

	if (!mem)
		return 0;

	*ret = __dma_alloc_from_coherent(dev, mem, size, dma_handle);
	return 1;
}

void *dma_alloc_from_global_coherent(struct device *dev, ssize_t size,
				     dma_addr_t *dma_handle)
{
	if (!dma_coherent_default_memory)
		return NULL;

	return __dma_alloc_from_coherent(dev, dma_coherent_default_memory, size,
					 dma_handle);
}

static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
				       int order, void *vaddr)
{
	if (mem && vaddr >= mem->virt_base && vaddr <
		   (mem->virt_base + ((dma_addr_t)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;
}

/**
 * dma_release_from_dev_coherent() - free memory to 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 the caller should
 * proceed with releasing memory from generic pools.
 */
int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr)
{
	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);

	return __dma_release_from_coherent(mem, order, vaddr);
}

int dma_release_from_global_coherent(int order, void *vaddr)
{
	if (!dma_coherent_default_memory)
		return 0;

	return __dma_release_from_coherent(dma_coherent_default_memory, order,
			vaddr);
}

static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
		struct vm_area_struct *vma, void *vaddr, size_t size, int *ret)
{
	if (mem && vaddr >= mem->virt_base && vaddr + size <=
		   (mem->virt_base + ((dma_addr_t)mem->size << PAGE_SHIFT))) {
		unsigned long off = vma->vm_pgoff;
		int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
		unsigned long 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;
}

/**
 * dma_mmap_from_dev_coherent() - mmap memory from the device coherent pool
 * @dev:	device from which the memory was allocated
 * @vma:	vm_area for the userspace memory
 * @vaddr:	cpu address returned by dma_alloc_from_dev_coherent
 * @size:	size of the memory buffer allocated
 * @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 @vaddr belongs to the device coherent pool and the caller
 * should return @ret, or 0 if they should proceed with mapping memory from
 * generic areas.
 */
int dma_mmap_from_dev_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);

	return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
}

int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr,
				   size_t size, int *ret)
{
	if (!dma_coherent_default_memory)
		return 0;

	return __dma_mmap_from_coherent(dma_coherent_default_memory, vma,
					vaddr, size, ret);
}

/*
 * 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;
	int ret;

	if (!mem) {
		ret = dma_init_coherent_memory(rmem->base, rmem->base,
					       rmem->size, &mem);
		if (ret) {
			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 ret;
		}
	}
	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
b2441318	1	// SPDX-License-Identifier: GPL-2.0
ee7e5516 DB	2	/*
	3	* Coherent per-device memory handling.
	4	* Borrowed from i386
	5	*/
6b03ae0d	6	#include <linux/io.h>
5a0e3ad6	7	#include <linux/slab.h>
ee7e5516	8	#include <linux/kernel.h>
08a999ce	9	#include <linux/module.h>
e0d07278	10	#include <linux/dma-direct.h>
0a0f0d8b	11	#include <linux/dma-map-ops.h>
ee7e5516 DB	12
	13	struct dma_coherent_mem {
	14	void *virt_base;
ed1d218c	15	dma_addr_t device_base;
88a984ba	16	unsigned long pfn_base;
ee7e5516	17	int size;
ee7e5516	18	unsigned long *bitmap;
7bfa5ab6	19	spinlock_t spinlock;
c41f9ea9	20	bool use_dev_dma_pfn_offset;
ee7e5516 DB	21	};
ee7e5516 DB	22
93228b44 VM	23	static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
	24
	25	static inline struct dma_coherent_mem dev_get_coherent_memory(struct device dev)
	26	{
	27	if (dev && dev->dma_mem)
	28	return dev->dma_mem;
43fc509c	29	return NULL;
93228b44 VM	30	}
93228b44 VM	31
c41f9ea9 VM	32	static inline dma_addr_t dma_get_device_base(struct device *dev,
	33	struct dma_coherent_mem * mem)
	34	{
	35	if (mem->use_dev_dma_pfn_offset)
e0d07278 JQ	36	return phys_to_dma(dev, PFN_PHYS(mem->pfn_base));
e0d07278 JQ	37	return mem->device_base;
c41f9ea9 VM	38	}
c41f9ea9 VM	39
82c5de0a CH	40	static int dma_init_coherent_memory(phys_addr_t phys_addr,
	41	dma_addr_t device_addr, size_t size,
	42	struct dma_coherent_mem **mem)
ee7e5516	43	{
7bfa5ab6	44	struct dma_coherent_mem *dma_mem = NULL;
be4311a2	45	void *mem_base = NULL;
ee7e5516 DB	46	int pages = size >> PAGE_SHIFT;
ee7e5516 DB	47	int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
d35b0996	48	int ret;
ee7e5516	49
d35b0996 AB	50	if (!size) {
d35b0996 AB	51	ret = -EINVAL;
ee7e5516	52	goto out;
d35b0996	53	}
ee7e5516	54
2436bdcd	55	mem_base = memremap(phys_addr, size, MEMREMAP_WC);
d35b0996 AB	56	if (!mem_base) {
d35b0996 AB	57	ret = -EINVAL;
ee7e5516	58	goto out;
d35b0996	59	}
7bfa5ab6	60	dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
d35b0996 AB	61	if (!dma_mem) {
d35b0996 AB	62	ret = -ENOMEM;
ee7e5516	63	goto out;
d35b0996	64	}
7bfa5ab6	65	dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
d35b0996 AB	66	if (!dma_mem->bitmap) {
d35b0996 AB	67	ret = -ENOMEM;
7bfa5ab6	68	goto out;
d35b0996	69	}
7bfa5ab6 MS	70
	71	dma_mem->virt_base = mem_base;
	72	dma_mem->device_base = device_addr;
	73	dma_mem->pfn_base = PFN_DOWN(phys_addr);
	74	dma_mem->size = pages;
7bfa5ab6	75	spin_lock_init(&dma_mem->spinlock);
ee7e5516	76
7bfa5ab6	77	*mem = dma_mem;
d35b0996	78	return 0;
ee7e5516	79
7bfa5ab6 MS	80	out:
7bfa5ab6 MS	81	kfree(dma_mem);
2436bdcd CH	82	if (mem_base)
2436bdcd CH	83	memunmap(mem_base);
d35b0996	84	return ret;
ee7e5516	85	}
7bfa5ab6 MS	86
	87	static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
	88	{
	89	if (!mem)
	90	return;
6b03ae0d	91
2436bdcd	92	memunmap(mem->virt_base);
7bfa5ab6 MS	93	kfree(mem->bitmap);
	94	kfree(mem);
	95	}
	96
	97	static int dma_assign_coherent_memory(struct device *dev,
	98	struct dma_coherent_mem *mem)
	99	{
93228b44 VM	100	if (!dev)
	101	return -ENODEV;
	102
7bfa5ab6 MS	103	if (dev->dma_mem)
	104	return -EBUSY;
	105
	106	dev->dma_mem = mem;
7bfa5ab6 MS	107	return 0;
	108	}
	109
a92df4f6 CH	110	/*
	111	* Declare a region of memory to be handed out by dma_alloc_coherent() when it
	112	* is asked for coherent memory for this device. This shall only be used
	113	* from platform code, usually based on the device tree description.
	114	*
	115	* phys_addr is the CPU physical address to which the memory is currently
	116	* assigned (this will be ioremapped so the CPU can access the region).
	117	*
	118	* device_addr is the DMA address the device needs to be programmed with to
	119	* actually address this memory (this will be handed out as the dma_addr_t in
	120	* dma_alloc_coherent()).
	121	*
	122	* size is the size of the area (must be a multiple of PAGE_SIZE).
	123	*
	124	* As a simplification for the platforms, only one such region of memory may
	125	* be declared per device.
	126	*/
7bfa5ab6	127	int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
82c5de0a	128	dma_addr_t device_addr, size_t size)
7bfa5ab6 MS	129	{
7bfa5ab6 MS	130	struct dma_coherent_mem *mem;
2436bdcd	131	int ret;
7bfa5ab6	132
82c5de0a	133	ret = dma_init_coherent_memory(phys_addr, device_addr, size, &mem);
2436bdcd CH	134	if (ret)
2436bdcd CH	135	return ret;
7bfa5ab6	136
2436bdcd CH	137	ret = dma_assign_coherent_memory(dev, mem);
	138	if (ret)
	139	dma_release_coherent_memory(mem);
	140	return ret;
7bfa5ab6	141	}
ee7e5516	142
a445e940 VM	143	static void __dma_alloc_from_coherent(struct device dev,
	144	struct dma_coherent_mem *mem,
	145	ssize_t size, dma_addr_t *dma_handle)
ee7e5516	146	{
ee7e5516	147	int order = get_order(size);
7bfa5ab6	148	unsigned long flags;
eccd83e1	149	int pageno;
43fc509c	150	void *ret;
ee7e5516	151
7bfa5ab6	152	spin_lock_irqsave(&mem->spinlock, flags);
0609697e	153
286c21de	154	if (unlikely(size > ((dma_addr_t)mem->size << PAGE_SHIFT)))
0609697e	155	goto err;
eccd83e1 AM	156
eccd83e1 AM	157	pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
0609697e PM	158	if (unlikely(pageno < 0))
	159	goto err;
	160
	161	/*
43fc509c	162	* Memory was found in the coherent area.
0609697e	163	*/
286c21de KG	164	*dma_handle = dma_get_device_base(dev, mem) +
	165	((dma_addr_t)pageno << PAGE_SHIFT);
	166	ret = mem->virt_base + ((dma_addr_t)pageno << PAGE_SHIFT);
dd01c75f	167	spin_unlock_irqrestore(&mem->spinlock, flags);
2436bdcd	168	memset(ret, 0, size);
43fc509c	169	return ret;
0609697e	170	err:
7bfa5ab6	171	spin_unlock_irqrestore(&mem->spinlock, flags);
43fc509c VM	172	return NULL;
	173	}
	174
	175	/**
	176	* dma_alloc_from_dev_coherent() - allocate memory from device coherent pool
	177	* @dev: device from which we allocate memory
	178	* @size: size of requested memory area
	179	* @dma_handle: This will be filled with the correct dma handle
	180	* @ret: This pointer will be filled with the virtual address
	181	* to allocated area.
	182	*
	183	* This function should be only called from per-arch dma_alloc_coherent()
	184	* to support allocation from per-device coherent memory pools.
	185	*
	186	* Returns 0 if dma_alloc_coherent should continue with allocating from
	187	* generic memory areas, or !0 if dma_alloc_coherent should return @ret.
	188	*/
	189	int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
	190	dma_addr_t dma_handle, void *ret)
	191	{
	192	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
	193
	194	if (!mem)
	195	return 0;
	196
a445e940	197	*ret = __dma_alloc_from_coherent(dev, mem, size, dma_handle);
82c5de0a	198	return 1;
ee7e5516 DB	199	}
ee7e5516 DB	200
a445e940 VM	201	void dma_alloc_from_global_coherent(struct device dev, ssize_t size,
a445e940 VM	202	dma_addr_t *dma_handle)
ee7e5516	203	{
43fc509c VM	204	if (!dma_coherent_default_memory)
	205	return NULL;
	206
a445e940 VM	207	return __dma_alloc_from_coherent(dev, dma_coherent_default_memory, size,
a445e940 VM	208	dma_handle);
43fc509c	209	}
ee7e5516	210
43fc509c VM	211	static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
	212	int order, void *vaddr)
	213	{
ee7e5516	214	if (mem && vaddr >= mem->virt_base && vaddr <
286c21de	215	(mem->virt_base + ((dma_addr_t)mem->size << PAGE_SHIFT))) {
ee7e5516	216	int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
7bfa5ab6	217	unsigned long flags;
ee7e5516	218
7bfa5ab6	219	spin_lock_irqsave(&mem->spinlock, flags);
ee7e5516	220	bitmap_release_region(mem->bitmap, page, order);
7bfa5ab6	221	spin_unlock_irqrestore(&mem->spinlock, flags);
ee7e5516 DB	222	return 1;
	223	}
	224	return 0;
	225	}
bca0fa5f MS	226
bca0fa5f MS	227	/**
43fc509c	228	* dma_release_from_dev_coherent() - free memory to device coherent memory pool
bca0fa5f	229	* @dev: device from which the memory was allocated
43fc509c VM	230	* @order: the order of pages allocated
43fc509c VM	231	* @vaddr: virtual address of allocated pages
bca0fa5f MS	232	*
bca0fa5f MS	233	* This checks whether the memory was allocated from the per-device
43fc509c	234	* coherent memory pool and if so, releases that memory.
bca0fa5f	235	*
43fc509c VM	236	* Returns 1 if we correctly released the memory, or 0 if the caller should
43fc509c VM	237	* proceed with releasing memory from generic pools.
bca0fa5f	238	*/
43fc509c	239	int dma_release_from_dev_coherent(struct device dev, int order, void vaddr)
bca0fa5f	240	{
93228b44	241	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
bca0fa5f	242
43fc509c VM	243	return __dma_release_from_coherent(mem, order, vaddr);
43fc509c VM	244	}
43fc509c VM	245
	246	int dma_release_from_global_coherent(int order, void *vaddr)
	247	{
	248	if (!dma_coherent_default_memory)
	249	return 0;
	250
	251	return __dma_release_from_coherent(dma_coherent_default_memory, order,
	252	vaddr);
	253	}
	254
	255	static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
	256	struct vm_area_struct vma, void vaddr, size_t size, int *ret)
	257	{
bca0fa5f	258	if (mem && vaddr >= mem->virt_base && vaddr + size <=
286c21de	259	(mem->virt_base + ((dma_addr_t)mem->size << PAGE_SHIFT))) {
bca0fa5f MS	260	unsigned long off = vma->vm_pgoff;
bca0fa5f MS	261	int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
286c21de	262	unsigned long user_count = vma_pages(vma);
9ca5d4fd	263	int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
bca0fa5f MS	264
	265	*ret = -ENXIO;
	266	if (off < count && user_count <= count - off) {
88a984ba	267	unsigned long pfn = mem->pfn_base + start + off;
bca0fa5f MS	268	*ret = remap_pfn_range(vma, vma->vm_start, pfn,
	269	user_count << PAGE_SHIFT,
	270	vma->vm_page_prot);
	271	}
	272	return 1;
	273	}
	274	return 0;
	275	}
43fc509c VM	276
	277	/**
	278	* dma_mmap_from_dev_coherent() - mmap memory from the device coherent pool
	279	* @dev: device from which the memory was allocated
	280	* @vma: vm_area for the userspace memory
	281	* @vaddr: cpu address returned by dma_alloc_from_dev_coherent
	282	* @size: size of the memory buffer allocated
	283	* @ret: result from remap_pfn_range()
	284	*
	285	* This checks whether the memory was allocated from the per-device
	286	* coherent memory pool and if so, maps that memory to the provided vma.
	287	*
41d0bbc7 RM	288	* Returns 1 if @vaddr belongs to the device coherent pool and the caller
	289	* should return @ret, or 0 if they should proceed with mapping memory from
	290	* generic areas.
43fc509c VM	291	*/
	292	int dma_mmap_from_dev_coherent(struct device dev, struct vm_area_struct vma,
	293	void vaddr, size_t size, int ret)
	294	{
	295	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
	296
	297	return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
	298	}
43fc509c VM	299
	300	int dma_mmap_from_global_coherent(struct vm_area_struct vma, void vaddr,
	301	size_t size, int *ret)
	302	{
	303	if (!dma_coherent_default_memory)
	304	return 0;
	305
	306	return __dma_mmap_from_coherent(dma_coherent_default_memory, vma,
	307	vaddr, size, ret);
	308	}
7bfa5ab6 MS	309
	310	/*
	311	* Support for reserved memory regions defined in device tree
	312	*/
	313	#ifdef CONFIG_OF_RESERVED_MEM
	314	#include <linux/of.h>
	315	#include <linux/of_fdt.h>
	316	#include <linux/of_reserved_mem.h>
	317
93228b44 VM	318	static struct reserved_mem *dma_reserved_default_memory __initdata;
93228b44 VM	319
7bfa5ab6 MS	320	static int rmem_dma_device_init(struct reserved_mem rmem, struct device dev)
	321	{
	322	struct dma_coherent_mem *mem = rmem->priv;
d35b0996 AB	323	int ret;
d35b0996 AB	324
6d573398 AB	325	if (!mem) {
6d573398 AB	326	ret = dma_init_coherent_memory(rmem->base, rmem->base,
82c5de0a	327	rmem->size, &mem);
6d573398 AB	328	if (ret) {
	329	pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
	330	&rmem->base, (unsigned long)rmem->size / SZ_1M);
	331	return ret;
	332	}
7bfa5ab6	333	}
c41f9ea9	334	mem->use_dev_dma_pfn_offset = true;
7bfa5ab6 MS	335	rmem->priv = mem;
	336	dma_assign_coherent_memory(dev, mem);
	337	return 0;
	338	}
	339
	340	static void rmem_dma_device_release(struct reserved_mem *rmem,
	341	struct device *dev)
	342	{
93228b44 VM	343	if (dev)
93228b44 VM	344	dev->dma_mem = NULL;
7bfa5ab6 MS	345	}
	346
	347	static const struct reserved_mem_ops rmem_dma_ops = {
	348	.device_init = rmem_dma_device_init,
	349	.device_release = rmem_dma_device_release,
	350	};
	351
	352	static int __init rmem_dma_setup(struct reserved_mem *rmem)
	353	{
	354	unsigned long node = rmem->fdt_node;
	355
	356	if (of_get_flat_dt_prop(node, "reusable", NULL))
	357	return -EINVAL;
	358
	359	#ifdef CONFIG_ARM
	360	if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
	361	pr_err("Reserved memory: regions without no-map are not yet supported\n");
	362	return -EINVAL;
	363	}
93228b44 VM	364
	365	if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) {
	366	WARN(dma_reserved_default_memory,
	367	"Reserved memory: region for default DMA coherent area is redefined\n");
	368	dma_reserved_default_memory = rmem;
	369	}
7bfa5ab6 MS	370	#endif
	371
	372	rmem->ops = &rmem_dma_ops;
	373	pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
	374	&rmem->base, (unsigned long)rmem->size / SZ_1M);
	375	return 0;
	376	}
93228b44 VM	377
	378	static int __init dma_init_reserved_memory(void)
	379	{
	380	const struct reserved_mem_ops *ops;
	381	int ret;
	382
	383	if (!dma_reserved_default_memory)
	384	return -ENOMEM;
	385
	386	ops = dma_reserved_default_memory->ops;
	387
	388	/*
	389	* We rely on rmem_dma_device_init() does not propagate error of
	390	* dma_assign_coherent_memory() for "NULL" device.
	391	*/
	392	ret = ops->device_init(dma_reserved_default_memory, NULL);
	393
	394	if (!ret) {
	395	dma_coherent_default_memory = dma_reserved_default_memory->priv;
	396	pr_info("DMA: default coherent area is set\n");
	397	}
	398
	399	return ret;
	400	}
	401
	402	core_initcall(dma_init_reserved_memory);
	403
7bfa5ab6 MS	404	RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
7bfa5ab6 MS	405	#endif