[linux-2.6-block.git] / drivers / base / dma-contiguous.c

/*
 * Contiguous Memory Allocator for DMA mapping framework
 * Copyright (c) 2010-2011 by Samsung Electronics.
 * Written by:
 *	Marek Szyprowski <m.szyprowski@samsung.com>
 *	Michal Nazarewicz <mina86@mina86.com>
 *
 * 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 optional) any later version of the license.
 */

#define pr_fmt(fmt) "cma: " fmt

#ifdef CONFIG_CMA_DEBUG
#ifndef DEBUG
#  define DEBUG
#endif
#endif

#include <asm/page.h>
#include <asm/dma-contiguous.h>

#include <linux/memblock.h>
#include <linux/err.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/page-isolation.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/mm_types.h>
#include <linux/dma-contiguous.h>

struct cma {
	unsigned long	base_pfn;
	unsigned long	count;
	unsigned long	*bitmap;
};

struct cma *dma_contiguous_default_area;

#ifdef CONFIG_CMA_SIZE_MBYTES
#define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
#else
#define CMA_SIZE_MBYTES 0
#endif

/*
 * Default global CMA area size can be defined in kernel's .config.
 * This is useful mainly for distro maintainers to create a kernel
 * that works correctly for most supported systems.
 * The size can be set in bytes or as a percentage of the total memory
 * in the system.
 *
 * Users, who want to set the size of global CMA area for their system
 * should use cma= kernel parameter.
 */
static const phys_addr_t size_bytes = CMA_SIZE_MBYTES * SZ_1M;
static phys_addr_t size_cmdline = -1;

static int __init early_cma(char *p)
{
	pr_debug("%s(%s)\n", __func__, p);
	size_cmdline = memparse(p, &p);
	return 0;
}
early_param("cma", early_cma);

#ifdef CONFIG_CMA_SIZE_PERCENTAGE

static phys_addr_t __init __maybe_unused cma_early_percent_memory(void)
{
	struct memblock_region *reg;
	unsigned long total_pages = 0;

	/*
	 * We cannot use memblock_phys_mem_size() here, because
	 * memblock_analyze() has not been called yet.
	 */
	for_each_memblock(memory, reg)
		total_pages += memblock_region_memory_end_pfn(reg) -
			       memblock_region_memory_base_pfn(reg);

	return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
}

#else

static inline __maybe_unused phys_addr_t cma_early_percent_memory(void)
{
	return 0;
}

#endif

/**
 * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling
 * @limit: End address of the reserved memory (optional, 0 for any).
 *
 * This function reserves memory from early allocator. It should be
 * called by arch specific code once the early allocator (memblock or bootmem)
 * has been activated and all other subsystems have already allocated/reserved
 * memory.
 */
void __init dma_contiguous_reserve(phys_addr_t limit)
{
	phys_addr_t selected_size = 0;

	pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);

	if (size_cmdline != -1) {
		selected_size = size_cmdline;
	} else {
#ifdef CONFIG_CMA_SIZE_SEL_MBYTES
		selected_size = size_bytes;
#elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
		selected_size = cma_early_percent_memory();
#elif defined(CONFIG_CMA_SIZE_SEL_MIN)
		selected_size = min(size_bytes, cma_early_percent_memory());
#elif defined(CONFIG_CMA_SIZE_SEL_MAX)
		selected_size = max(size_bytes, cma_early_percent_memory());
#endif
	}

	if (selected_size && !dma_contiguous_default_area) {
		pr_debug("%s: reserving %ld MiB for global area\n", __func__,
			 (unsigned long)selected_size / SZ_1M);

		dma_contiguous_reserve_area(selected_size, 0, limit,
					    &dma_contiguous_default_area);
	}
};

static DEFINE_MUTEX(cma_mutex);

static int __init cma_activate_area(struct cma *cma)
{
	int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
	unsigned i = cma->count >> pageblock_order;
	struct zone *zone;

	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);

	if (!cma->bitmap)
		return -ENOMEM;

	WARN_ON_ONCE(!pfn_valid(pfn));
	zone = page_zone(pfn_to_page(pfn));

	do {
		unsigned j;
		base_pfn = pfn;
		for (j = pageblock_nr_pages; j; --j, pfn++) {
			WARN_ON_ONCE(!pfn_valid(pfn));
			if (page_zone(pfn_to_page(pfn)) != zone)
				return -EINVAL;
		}
		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
	} while (--i);

	return 0;
}

static struct cma cma_areas[MAX_CMA_AREAS];
static unsigned cma_area_count;

static int __init cma_init_reserved_areas(void)
{
	int i;

	for (i = 0; i < cma_area_count; i++) {
		int ret = cma_activate_area(&cma_areas[i]);
		if (ret)
			return ret;
	}

	return 0;
}
core_initcall(cma_init_reserved_areas);

/**
 * dma_contiguous_reserve_area() - reserve custom contiguous area
 * @size: Size of the reserved area (in bytes),
 * @base: Base address of the reserved area optional, use 0 for any
 * @limit: End address of the reserved memory (optional, 0 for any).
 * @res_cma: Pointer to store the created cma region.
 *
 * This function reserves memory from early allocator. It should be
 * called by arch specific code once the early allocator (memblock or bootmem)
 * has been activated and all other subsystems have already allocated/reserved
 * memory. This function allows to create custom reserved areas for specific
 * devices.
 */
int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
				       phys_addr_t limit, struct cma **res_cma)
{
	struct cma *cma = &cma_areas[cma_area_count];
	phys_addr_t alignment;
	int ret = 0;

	pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
		 (unsigned long)size, (unsigned long)base,
		 (unsigned long)limit);

	/* Sanity checks */
	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
		pr_err("Not enough slots for CMA reserved regions!\n");
		return -ENOSPC;
	}

	if (!size)
		return -EINVAL;

	/* Sanitise input arguments */
	alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
	base = ALIGN(base, alignment);
	size = ALIGN(size, alignment);
	limit &= ~(alignment - 1);

	/* Reserve memory */
	if (base) {
		if (memblock_is_region_reserved(base, size) ||
		    memblock_reserve(base, size) < 0) {
			ret = -EBUSY;
			goto err;
		}
	} else {
		/*
		 * Use __memblock_alloc_base() since
		 * memblock_alloc_base() panic()s.
		 */
		phys_addr_t addr = __memblock_alloc_base(size, alignment, limit);
		if (!addr) {
			ret = -ENOMEM;
			goto err;
		} else {
			base = addr;
		}
	}

	/*
	 * Each reserved area must be initialised later, when more kernel
	 * subsystems (like slab allocator) are available.
	 */
	cma->base_pfn = PFN_DOWN(base);
	cma->count = size >> PAGE_SHIFT;
	*res_cma = cma;
	cma_area_count++;

	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
		(unsigned long)base);

	/* Architecture specific contiguous memory fixup. */
	dma_contiguous_early_fixup(base, size);
	return 0;
err:
	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
	return ret;
}

/**
 * dma_alloc_from_contiguous() - allocate pages from contiguous area
 * @dev:   Pointer to device for which the allocation is performed.
 * @count: Requested number of pages.
 * @align: Requested alignment of pages (in PAGE_SIZE order).
 *
 * This function allocates memory buffer for specified device. It uses
 * device specific contiguous memory area if available or the default
 * global one. Requires architecture specific get_dev_cma_area() helper
 * function.
 */
struct page *dma_alloc_from_contiguous(struct device *dev, int count,
				       unsigned int align)
{
	unsigned long mask, pfn, pageno, start = 0;
	struct cma *cma = dev_get_cma_area(dev);
	struct page *page = NULL;
	int ret;

	if (!cma || !cma->count)
		return NULL;

	if (align > CONFIG_CMA_ALIGNMENT)
		align = CONFIG_CMA_ALIGNMENT;

	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
		 count, align);

	if (!count)
		return NULL;

	mask = (1 << align) - 1;

	mutex_lock(&cma_mutex);

	for (;;) {
		pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
						    start, count, mask);
		if (pageno >= cma->count)
			break;

		pfn = cma->base_pfn + pageno;
		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
		if (ret == 0) {
			bitmap_set(cma->bitmap, pageno, count);
			page = pfn_to_page(pfn);
			break;
		} else if (ret != -EBUSY) {
			break;
		}
		pr_debug("%s(): memory range at %p is busy, retrying\n",
			 __func__, pfn_to_page(pfn));
		/* try again with a bit different memory target */
		start = pageno + mask + 1;
	}

	mutex_unlock(&cma_mutex);
	pr_debug("%s(): returned %p\n", __func__, page);
	return page;
}

/**
 * dma_release_from_contiguous() - release allocated pages
 * @dev:   Pointer to device for which the pages were allocated.
 * @pages: Allocated pages.
 * @count: Number of allocated pages.
 *
 * This function releases memory allocated by dma_alloc_from_contiguous().
 * It returns false when provided pages do not belong to contiguous area and
 * true otherwise.
 */
bool dma_release_from_contiguous(struct device *dev, struct page *pages,
				 int count)
{
	struct cma *cma = dev_get_cma_area(dev);
	unsigned long pfn;

	if (!cma || !pages)
		return false;

	pr_debug("%s(page %p)\n", __func__, (void *)pages);

	pfn = page_to_pfn(pages);

	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
		return false;

	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);

	mutex_lock(&cma_mutex);
	bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
	free_contig_range(pfn, count);
	mutex_unlock(&cma_mutex);

	return true;
}
Commit	Line	Data
c64be2bb MS	1	/*
	2	* Contiguous Memory Allocator for DMA mapping framework
	3	* Copyright (c) 2010-2011 by Samsung Electronics.
	4	* Written by:
	5	* Marek Szyprowski <m.szyprowski@samsung.com>
	6	* Michal Nazarewicz <mina86@mina86.com>
	7	*
	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License as
	10	* published by the Free Software Foundation; either version 2 of the
	11	* License or (at your optional) any later version of the license.
	12	*/
	13
	14	#define pr_fmt(fmt) "cma: " fmt
	15
	16	#ifdef CONFIG_CMA_DEBUG
	17	#ifndef DEBUG
	18	# define DEBUG
	19	#endif
	20	#endif
	21
	22	#include <asm/page.h>
	23	#include <asm/dma-contiguous.h>
	24
	25	#include <linux/memblock.h>
	26	#include <linux/err.h>
	27	#include <linux/mm.h>
	28	#include <linux/mutex.h>
	29	#include <linux/page-isolation.h>
446c82fc	30	#include <linux/sizes.h>
c64be2bb MS	31	#include <linux/slab.h>
	32	#include <linux/swap.h>
	33	#include <linux/mm_types.h>
	34	#include <linux/dma-contiguous.h>
	35
c64be2bb MS	36	struct cma {
	37	unsigned long base_pfn;
	38	unsigned long count;
	39	unsigned long *bitmap;
	40	};
	41
	42	struct cma *dma_contiguous_default_area;
	43
	44	#ifdef CONFIG_CMA_SIZE_MBYTES
	45	#define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
	46	#else
	47	#define CMA_SIZE_MBYTES 0
	48	#endif
	49
	50	/*
	51	* Default global CMA area size can be defined in kernel's .config.
73678804	52	* This is useful mainly for distro maintainers to create a kernel
c64be2bb MS	53	* that works correctly for most supported systems.
	54	* The size can be set in bytes or as a percentage of the total memory
	55	* in the system.
	56	*
	57	* Users, who want to set the size of global CMA area for their system
	58	* should use cma= kernel parameter.
	59	*/
4009793e VA	60	static const phys_addr_t size_bytes = CMA_SIZE_MBYTES * SZ_1M;
4009793e VA	61	static phys_addr_t size_cmdline = -1;
c64be2bb MS	62
	63	static int __init early_cma(char *p)
	64	{
	65	pr_debug("%s(%s)\n", __func__, p);
	66	size_cmdline = memparse(p, &p);
	67	return 0;
	68	}
	69	early_param("cma", early_cma);
	70
	71	#ifdef CONFIG_CMA_SIZE_PERCENTAGE
	72
4009793e	73	static phys_addr_t __init __maybe_unused cma_early_percent_memory(void)
c64be2bb MS	74	{
	75	struct memblock_region *reg;
	76	unsigned long total_pages = 0;
	77
	78	/*
	79	* We cannot use memblock_phys_mem_size() here, because
	80	* memblock_analyze() has not been called yet.
	81	*/
	82	for_each_memblock(memory, reg)
	83	total_pages += memblock_region_memory_end_pfn(reg) -
	84	memblock_region_memory_base_pfn(reg);
	85
	86	return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
	87	}
	88
	89	#else
	90
4009793e	91	static inline __maybe_unused phys_addr_t cma_early_percent_memory(void)
c64be2bb MS	92	{
	93	return 0;
	94	}
	95
	96	#endif
	97
	98	/**
a2547380	99	* dma_contiguous_reserve() - reserve area(s) for contiguous memory handling
c64be2bb MS	100	* @limit: End address of the reserved memory (optional, 0 for any).
	101	*
	102	* This function reserves memory from early allocator. It should be
	103	* called by arch specific code once the early allocator (memblock or bootmem)
	104	* has been activated and all other subsystems have already allocated/reserved
	105	* memory.
	106	*/
	107	void __init dma_contiguous_reserve(phys_addr_t limit)
	108	{
4009793e	109	phys_addr_t selected_size = 0;
c64be2bb MS	110
	111	pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
	112
	113	if (size_cmdline != -1) {
	114	selected_size = size_cmdline;
	115	} else {
	116	#ifdef CONFIG_CMA_SIZE_SEL_MBYTES
	117	selected_size = size_bytes;
	118	#elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
	119	selected_size = cma_early_percent_memory();
	120	#elif defined(CONFIG_CMA_SIZE_SEL_MIN)
	121	selected_size = min(size_bytes, cma_early_percent_memory());
	122	#elif defined(CONFIG_CMA_SIZE_SEL_MAX)
	123	selected_size = max(size_bytes, cma_early_percent_memory());
	124	#endif
	125	}
	126
a2547380	127	if (selected_size && !dma_contiguous_default_area) {
c64be2bb	128	pr_debug("%s: reserving %ld MiB for global area\n", __func__,
4009793e	129	(unsigned long)selected_size / SZ_1M);
c64be2bb	130
a2547380 MS	131	dma_contiguous_reserve_area(selected_size, 0, limit,
a2547380 MS	132	&dma_contiguous_default_area);
c64be2bb MS	133	}
	134	};
	135
	136	static DEFINE_MUTEX(cma_mutex);
	137
a2547380	138	static int __init cma_activate_area(struct cma *cma)
c64be2bb	139	{
a2547380 MS	140	int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
	141	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
	142	unsigned i = cma->count >> pageblock_order;
c64be2bb MS	143	struct zone *zone;
c64be2bb MS	144
a2547380 MS	145	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
	146
	147	if (!cma->bitmap)
	148	return -ENOMEM;
	149
c64be2bb MS	150	WARN_ON_ONCE(!pfn_valid(pfn));
	151	zone = page_zone(pfn_to_page(pfn));
	152
	153	do {
	154	unsigned j;
	155	base_pfn = pfn;
	156	for (j = pageblock_nr_pages; j; --j, pfn++) {
	157	WARN_ON_ONCE(!pfn_valid(pfn));
	158	if (page_zone(pfn_to_page(pfn)) != zone)
	159	return -EINVAL;
	160	}
	161	init_cma_reserved_pageblock(pfn_to_page(base_pfn));
	162	} while (--i);
c64be2bb	163
a2547380	164	return 0;
c64be2bb MS	165	}
c64be2bb MS	166
a2547380 MS	167	static struct cma cma_areas[MAX_CMA_AREAS];
a2547380 MS	168	static unsigned cma_area_count;
c64be2bb MS	169
	170	static int __init cma_init_reserved_areas(void)
	171	{
a2547380	172	int i;
c64be2bb	173
a2547380 MS	174	for (i = 0; i < cma_area_count; i++) {
	175	int ret = cma_activate_area(&cma_areas[i]);
	176	if (ret)
	177	return ret;
c64be2bb	178	}
a2547380	179
c64be2bb MS	180	return 0;
	181	}
	182	core_initcall(cma_init_reserved_areas);
	183
	184	/**
a2547380 MS	185	* dma_contiguous_reserve_area() - reserve custom contiguous area
	186	* @size: Size of the reserved area (in bytes),
	187	* @base: Base address of the reserved area optional, use 0 for any
c64be2bb	188	* @limit: End address of the reserved memory (optional, 0 for any).
a2547380	189	* @res_cma: Pointer to store the created cma region.
c64be2bb	190	*
a2547380 MS	191	* This function reserves memory from early allocator. It should be
	192	* called by arch specific code once the early allocator (memblock or bootmem)
	193	* has been activated and all other subsystems have already allocated/reserved
	194	* memory. This function allows to create custom reserved areas for specific
	195	* devices.
c64be2bb	196	*/
a2547380 MS	197	int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
a2547380 MS	198	phys_addr_t limit, struct cma **res_cma)
c64be2bb	199	{
a2547380	200	struct cma *cma = &cma_areas[cma_area_count];
4009793e	201	phys_addr_t alignment;
a2547380	202	int ret = 0;
c64be2bb MS	203
	204	pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
	205	(unsigned long)size, (unsigned long)base,
	206	(unsigned long)limit);
	207
	208	/* Sanity checks */
a2547380	209	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
c64be2bb MS	210	pr_err("Not enough slots for CMA reserved regions!\n");
	211	return -ENOSPC;
	212	}
	213
	214	if (!size)
	215	return -EINVAL;
	216
	217	/* Sanitise input arguments */
7ce9bf1f	218	alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
c64be2bb MS	219	base = ALIGN(base, alignment);
	220	size = ALIGN(size, alignment);
	221	limit &= ~(alignment - 1);
	222
	223	/* Reserve memory */
	224	if (base) {
	225	if (memblock_is_region_reserved(base, size) \|\|
	226	memblock_reserve(base, size) < 0) {
a2547380	227	ret = -EBUSY;
c64be2bb MS	228	goto err;
	229	}
	230	} else {
	231	/*
	232	* Use __memblock_alloc_base() since
	233	* memblock_alloc_base() panic()s.
	234	*/
	235	phys_addr_t addr = __memblock_alloc_base(size, alignment, limit);
	236	if (!addr) {
a2547380	237	ret = -ENOMEM;
c64be2bb	238	goto err;
c64be2bb MS	239	} else {
	240	base = addr;
	241	}
	242	}
	243
	244	/*
	245	* Each reserved area must be initialised later, when more kernel
	246	* subsystems (like slab allocator) are available.
	247	*/
a2547380 MS	248	cma->base_pfn = PFN_DOWN(base);
	249	cma->count = size >> PAGE_SHIFT;
	250	*res_cma = cma;
	251	cma_area_count++;
	252
4009793e	253	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
c64be2bb MS	254	(unsigned long)base);
	255
	256	/* Architecture specific contiguous memory fixup. */
	257	dma_contiguous_early_fixup(base, size);
	258	return 0;
	259	err:
4009793e	260	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
a2547380	261	return ret;
c64be2bb MS	262	}
	263
	264	/**
	265	* dma_alloc_from_contiguous() - allocate pages from contiguous area
	266	* @dev: Pointer to device for which the allocation is performed.
	267	* @count: Requested number of pages.
	268	* @align: Requested alignment of pages (in PAGE_SIZE order).
	269	*
	270	* This function allocates memory buffer for specified device. It uses
	271	* device specific contiguous memory area if available or the default
	272	* global one. Requires architecture specific get_dev_cma_area() helper
	273	* function.
	274	*/
	275	struct page dma_alloc_from_contiguous(struct device dev, int count,
	276	unsigned int align)
	277	{
	278	unsigned long mask, pfn, pageno, start = 0;
	279	struct cma *cma = dev_get_cma_area(dev);
bdd43cb3	280	struct page *page = NULL;
c64be2bb MS	281	int ret;
	282
	283	if (!cma \|\| !cma->count)
	284	return NULL;
	285
	286	if (align > CONFIG_CMA_ALIGNMENT)
	287	align = CONFIG_CMA_ALIGNMENT;
	288
	289	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
	290	count, align);
	291
	292	if (!count)
	293	return NULL;
	294
	295	mask = (1 << align) - 1;
	296
	297	mutex_lock(&cma_mutex);
	298
	299	for (;;) {
	300	pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
	301	start, count, mask);
bdd43cb3 MN	302	if (pageno >= cma->count)
bdd43cb3 MN	303	break;
c64be2bb MS	304
	305	pfn = cma->base_pfn + pageno;
	306	ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
	307	if (ret == 0) {
	308	bitmap_set(cma->bitmap, pageno, count);
bdd43cb3	309	page = pfn_to_page(pfn);
c64be2bb MS	310	break;
c64be2bb MS	311	} else if (ret != -EBUSY) {
bdd43cb3	312	break;
c64be2bb MS	313	}
	314	pr_debug("%s(): memory range at %p is busy, retrying\n",
	315	__func__, pfn_to_page(pfn));
	316	/* try again with a bit different memory target */
	317	start = pageno + mask + 1;
	318	}
	319
	320	mutex_unlock(&cma_mutex);
bdd43cb3 MN	321	pr_debug("%s(): returned %p\n", __func__, page);
bdd43cb3 MN	322	return page;
c64be2bb MS	323	}
	324
	325	/**
	326	* dma_release_from_contiguous() - release allocated pages
	327	* @dev: Pointer to device for which the pages were allocated.
	328	* @pages: Allocated pages.
	329	* @count: Number of allocated pages.
	330	*
	331	* This function releases memory allocated by dma_alloc_from_contiguous().
	332	* It returns false when provided pages do not belong to contiguous area and
	333	* true otherwise.
	334	*/
	335	bool dma_release_from_contiguous(struct device dev, struct page pages,
	336	int count)
	337	{
	338	struct cma *cma = dev_get_cma_area(dev);
	339	unsigned long pfn;
	340
	341	if (!cma \|\| !pages)
	342	return false;
	343
	344	pr_debug("%s(page %p)\n", __func__, (void *)pages);
	345
	346	pfn = page_to_pfn(pages);
	347
	348	if (pfn < cma->base_pfn \|\| pfn >= cma->base_pfn + cma->count)
	349	return false;
	350
	351	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
	352
	353	mutex_lock(&cma_mutex);
	354	bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
	355	free_contig_range(pfn, count);
	356	mutex_unlock(&cma_mutex);
	357
	358	return true;
	359	}