[net-next-2.6.git] / arch / arm / mm / consistent.c

/*
 *  linux/arch/arm/mm/consistent.c
 *
 *  Copyright (C) 2000-2004 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  DMA uncached mapping support.
 */
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>

#include <asm/memory.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/sizes.h>

/* Sanity check size */
#if (CONSISTENT_DMA_SIZE % SZ_2M)
#error "CONSISTENT_DMA_SIZE must be multiple of 2MiB"
#endif

#define CONSISTENT_END	(0xffe00000)
#define CONSISTENT_BASE	(CONSISTENT_END - CONSISTENT_DMA_SIZE)

#define CONSISTENT_OFFSET(x)	(((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)
#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PGDIR_SHIFT)
#define NUM_CONSISTENT_PTES (CONSISTENT_DMA_SIZE >> PGDIR_SHIFT)


/*
 * These are the page tables (2MB each) covering uncached, DMA consistent allocations
 */
static pte_t *consistent_pte[NUM_CONSISTENT_PTES];
static DEFINE_SPINLOCK(consistent_lock);

/*
 * VM region handling support.
 *
 * This should become something generic, handling VM region allocations for
 * vmalloc and similar (ioremap, module space, etc).
 *
 * I envisage vmalloc()'s supporting vm_struct becoming:
 *
 *  struct vm_struct {
 *    struct vm_region	region;
 *    unsigned long	flags;
 *    struct page	**pages;
 *    unsigned int	nr_pages;
 *    unsigned long	phys_addr;
 *  };
 *
 * get_vm_area() would then call vm_region_alloc with an appropriate
 * struct vm_region head (eg):
 *
 *  struct vm_region vmalloc_head = {
 *	.vm_list	= LIST_HEAD_INIT(vmalloc_head.vm_list),
 *	.vm_start	= VMALLOC_START,
 *	.vm_end		= VMALLOC_END,
 *  };
 *
 * However, vmalloc_head.vm_start is variable (typically, it is dependent on
 * the amount of RAM found at boot time.)  I would imagine that get_vm_area()
 * would have to initialise this each time prior to calling vm_region_alloc().
 */
struct vm_region {
	struct list_head	vm_list;
	unsigned long		vm_start;
	unsigned long		vm_end;
	struct page		*vm_pages;
	int			vm_active;
};

static struct vm_region consistent_head = {
	.vm_list	= LIST_HEAD_INIT(consistent_head.vm_list),
	.vm_start	= CONSISTENT_BASE,
	.vm_end		= CONSISTENT_END,
};

static struct vm_region *
vm_region_alloc(struct vm_region *head, size_t size, gfp_t gfp)
{
	unsigned long addr = head->vm_start, end = head->vm_end - size;
	unsigned long flags;
	struct vm_region *c, *new;

	new = kmalloc(sizeof(struct vm_region), gfp);
	if (!new)
		goto out;

	spin_lock_irqsave(&consistent_lock, flags);

	list_for_each_entry(c, &head->vm_list, vm_list) {
		if ((addr + size) < addr)
			goto nospc;
		if ((addr + size) <= c->vm_start)
			goto found;
		addr = c->vm_end;
		if (addr > end)
			goto nospc;
	}

 found:
	/*
	 * Insert this entry _before_ the one we found.
	 */
	list_add_tail(&new->vm_list, &c->vm_list);
	new->vm_start = addr;
	new->vm_end = addr + size;
	new->vm_active = 1;

	spin_unlock_irqrestore(&consistent_lock, flags);
	return new;

 nospc:
	spin_unlock_irqrestore(&consistent_lock, flags);
	kfree(new);
 out:
	return NULL;
}

static struct vm_region *vm_region_find(struct vm_region *head, unsigned long addr)
{
	struct vm_region *c;
	
	list_for_each_entry(c, &head->vm_list, vm_list) {
		if (c->vm_active && c->vm_start == addr)
			goto out;
	}
	c = NULL;
 out:
	return c;
}

#ifdef CONFIG_HUGETLB_PAGE
#error ARM Coherent DMA allocator does not (yet) support huge TLB
#endif

static void *
__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
	    pgprot_t prot)
{
	struct page *page;
	struct vm_region *c;
	unsigned long order;
	u64 mask = ISA_DMA_THRESHOLD, limit;

	if (!consistent_pte[0]) {
		printk(KERN_ERR "%s: not initialised\n", __func__);
		dump_stack();
		return NULL;
	}

	if (dev) {
		mask = dev->coherent_dma_mask;

		/*
		 * Sanity check the DMA mask - it must be non-zero, and
		 * must be able to be satisfied by a DMA allocation.
		 */
		if (mask == 0) {
			dev_warn(dev, "coherent DMA mask is unset\n");
			goto no_page;
		}

		if ((~mask) & ISA_DMA_THRESHOLD) {
			dev_warn(dev, "coherent DMA mask %#llx is smaller "
				 "than system GFP_DMA mask %#llx\n",
				 mask, (unsigned long long)ISA_DMA_THRESHOLD);
			goto no_page;
		}
	}

	/*
	 * Sanity check the allocation size.
	 */
	size = PAGE_ALIGN(size);
	limit = (mask + 1) & ~mask;
	if ((limit && size >= limit) ||
	    size >= (CONSISTENT_END - CONSISTENT_BASE)) {
		printk(KERN_WARNING "coherent allocation too big "
		       "(requested %#x mask %#llx)\n", size, mask);
		goto no_page;
	}

	order = get_order(size);

	if (mask != 0xffffffff)
		gfp |= GFP_DMA;

	page = alloc_pages(gfp, order);
	if (!page)
		goto no_page;

	/*
	 * Invalidate any data that might be lurking in the
	 * kernel direct-mapped region for device DMA.
	 */
	{
		void *ptr = page_address(page);
		memset(ptr, 0, size);
		dmac_flush_range(ptr, ptr + size);
		outer_flush_range(__pa(ptr), __pa(ptr) + size);
	}

	/*
	 * Allocate a virtual address in the consistent mapping region.
	 */
	c = vm_region_alloc(&consistent_head, size,
			    gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
	if (c) {
		pte_t *pte;
		struct page *end = page + (1 << order);
		int idx = CONSISTENT_PTE_INDEX(c->vm_start);
		u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);

		pte = consistent_pte[idx] + off;
		c->vm_pages = page;

		split_page(page, order);

		/*
		 * Set the "dma handle"
		 */
		*handle = page_to_dma(dev, page);

		do {
			BUG_ON(!pte_none(*pte));

			/*
			 * x86 does not mark the pages reserved...
			 */
			SetPageReserved(page);
			set_pte_ext(pte, mk_pte(page, prot), 0);
			page++;
			pte++;
			off++;
			if (off >= PTRS_PER_PTE) {
				off = 0;
				pte = consistent_pte[++idx];
			}
		} while (size -= PAGE_SIZE);

		/*
		 * Free the otherwise unused pages.
		 */
		while (page < end) {
			__free_page(page);
			page++;
		}

		return (void *)c->vm_start;
	}

	if (page)
		__free_pages(page, order);
 no_page:
	*handle = ~0;
	return NULL;
}

/*
 * Allocate DMA-coherent memory space and return both the kernel remapped
 * virtual and bus address for that space.
 */
void *
dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
{
	void *memory;

	if (dma_alloc_from_coherent(dev, size, handle, &memory))
		return memory;

	if (arch_is_coherent()) {
		void *virt;

		virt = kmalloc(size, gfp);
		if (!virt)
			return NULL;
		*handle =  virt_to_dma(dev, virt);

		return virt;
	}

	return __dma_alloc(dev, size, handle, gfp,
			   pgprot_noncached(pgprot_kernel));
}
EXPORT_SYMBOL(dma_alloc_coherent);

/*
 * Allocate a writecombining region, in much the same way as
 * dma_alloc_coherent above.
 */
void *
dma_alloc_writecombine(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
{
	return __dma_alloc(dev, size, handle, gfp,
			   pgprot_writecombine(pgprot_kernel));
}
EXPORT_SYMBOL(dma_alloc_writecombine);

static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
		    void *cpu_addr, dma_addr_t dma_addr, size_t size)
{
	unsigned long flags, user_size, kern_size;
	struct vm_region *c;
	int ret = -ENXIO;

	user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;

	spin_lock_irqsave(&consistent_lock, flags);
	c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
	spin_unlock_irqrestore(&consistent_lock, flags);

	if (c) {
		unsigned long off = vma->vm_pgoff;

		kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;

		if (off < kern_size &&
		    user_size <= (kern_size - off)) {
			ret = remap_pfn_range(vma, vma->vm_start,
					      page_to_pfn(c->vm_pages) + off,
					      user_size << PAGE_SHIFT,
					      vma->vm_page_prot);
		}
	}

	return ret;
}

int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
		      void *cpu_addr, dma_addr_t dma_addr, size_t size)
{
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
	return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
}
EXPORT_SYMBOL(dma_mmap_coherent);

int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
			  void *cpu_addr, dma_addr_t dma_addr, size_t size)
{
	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
	return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
}
EXPORT_SYMBOL(dma_mmap_writecombine);

/*
 * free a page as defined by the above mapping.
 * Must not be called with IRQs disabled.
 */
void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
{
	struct vm_region *c;
	unsigned long flags, addr;
	pte_t *ptep;
	int idx;
	u32 off;

	WARN_ON(irqs_disabled());

	if (dma_release_from_coherent(dev, get_order(size), cpu_addr))
		return;

	if (arch_is_coherent()) {
		kfree(cpu_addr);
		return;
	}

	size = PAGE_ALIGN(size);

	spin_lock_irqsave(&consistent_lock, flags);
	c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
	if (!c)
		goto no_area;

	c->vm_active = 0;
	spin_unlock_irqrestore(&consistent_lock, flags);

	if ((c->vm_end - c->vm_start) != size) {
		printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
		       __func__, c->vm_end - c->vm_start, size);
		dump_stack();
		size = c->vm_end - c->vm_start;
	}

	idx = CONSISTENT_PTE_INDEX(c->vm_start);
	off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
	ptep = consistent_pte[idx] + off;
	addr = c->vm_start;
	do {
		pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
		unsigned long pfn;

		ptep++;
		addr += PAGE_SIZE;
		off++;
		if (off >= PTRS_PER_PTE) {
			off = 0;
			ptep = consistent_pte[++idx];
		}

		if (!pte_none(pte) && pte_present(pte)) {
			pfn = pte_pfn(pte);

			if (pfn_valid(pfn)) {
				struct page *page = pfn_to_page(pfn);

				/*
				 * x86 does not mark the pages reserved...
				 */
				ClearPageReserved(page);

				__free_page(page);
				continue;
			}
		}

		printk(KERN_CRIT "%s: bad page in kernel page table\n",
		       __func__);
	} while (size -= PAGE_SIZE);

	flush_tlb_kernel_range(c->vm_start, c->vm_end);

	spin_lock_irqsave(&consistent_lock, flags);
	list_del(&c->vm_list);
	spin_unlock_irqrestore(&consistent_lock, flags);

	kfree(c);
	return;

 no_area:
	spin_unlock_irqrestore(&consistent_lock, flags);
	printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
	       __func__, cpu_addr);
	dump_stack();
}
EXPORT_SYMBOL(dma_free_coherent);

/*
 * Initialise the consistent memory allocation.
 */
static int __init consistent_init(void)
{
	pgd_t *pgd;
	pmd_t *pmd;
	pte_t *pte;
	int ret = 0, i = 0;
	u32 base = CONSISTENT_BASE;

	do {
		pgd = pgd_offset(&init_mm, base);
		pmd = pmd_alloc(&init_mm, pgd, base);
		if (!pmd) {
			printk(KERN_ERR "%s: no pmd tables\n", __func__);
			ret = -ENOMEM;
			break;
		}
		WARN_ON(!pmd_none(*pmd));

		pte = pte_alloc_kernel(pmd, base);
		if (!pte) {
			printk(KERN_ERR "%s: no pte tables\n", __func__);
			ret = -ENOMEM;
			break;
		}

		consistent_pte[i++] = pte;
		base += (1 << PGDIR_SHIFT);
	} while (base < CONSISTENT_END);

	return ret;
}

core_initcall(consistent_init);

/*
 * Make an area consistent for devices.
 * Note: Drivers should NOT use this function directly, as it will break
 * platforms with CONFIG_DMABOUNCE.
 * Use the driver DMA support - see dma-mapping.h (dma_sync_*)
 */
void dma_cache_maint(const void *start, size_t size, int direction)
{
	const void *end = start + size;

	BUG_ON(!virt_addr_valid(start) || !virt_addr_valid(end - 1));

	switch (direction) {
	case DMA_FROM_DEVICE:		/* invalidate only */
		dmac_inv_range(start, end);
		outer_inv_range(__pa(start), __pa(end));
		break;
	case DMA_TO_DEVICE:		/* writeback only */
		dmac_clean_range(start, end);
		outer_clean_range(__pa(start), __pa(end));
		break;
	case DMA_BIDIRECTIONAL:		/* writeback and invalidate */
		dmac_flush_range(start, end);
		outer_flush_range(__pa(start), __pa(end));
		break;
	default:
		BUG();
	}
}
EXPORT_SYMBOL(dma_cache_maint);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/arm/mm/consistent.c
	3	*
	4	* Copyright (C) 2000-2004 Russell King
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* DMA uncached mapping support.
	11	*/
	12	#include <linux/module.h>
	13	#include <linux/mm.h>
	14	#include <linux/slab.h>
	15	#include <linux/errno.h>
	16	#include <linux/list.h>
	17	#include <linux/init.h>
	18	#include <linux/device.h>
	19	#include <linux/dma-mapping.h>
	20
23759dc6	21	#include <asm/memory.h>
1da177e4	22	#include <asm/cacheflush.h>
1da177e4	23	#include <asm/tlbflush.h>
37134cd5 KH	24	#include <asm/sizes.h>
	25
	26	/* Sanity check size */
	27	#if (CONSISTENT_DMA_SIZE % SZ_2M)
	28	#error "CONSISTENT_DMA_SIZE must be multiple of 2MiB"
	29	#endif
1da177e4	30
1da177e4	31	#define CONSISTENT_END (0xffe00000)
37134cd5 KH	32	#define CONSISTENT_BASE (CONSISTENT_END - CONSISTENT_DMA_SIZE)
37134cd5 KH	33
1da177e4	34	#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)
37134cd5 KH	35	#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PGDIR_SHIFT)
	36	#define NUM_CONSISTENT_PTES (CONSISTENT_DMA_SIZE >> PGDIR_SHIFT)
	37
1da177e4 LT	38
1da177e4 LT	39	/*
37134cd5	40	* These are the page tables (2MB each) covering uncached, DMA consistent allocations
1da177e4	41	*/
37134cd5	42	static pte_t *consistent_pte[NUM_CONSISTENT_PTES];
1da177e4 LT	43	static DEFINE_SPINLOCK(consistent_lock);
	44
	45	/*
	46	* VM region handling support.
	47	*
	48	* This should become something generic, handling VM region allocations for
	49	* vmalloc and similar (ioremap, module space, etc).
	50	*
	51	* I envisage vmalloc()'s supporting vm_struct becoming:
	52	*
	53	* struct vm_struct {
	54	* struct vm_region region;
	55	* unsigned long flags;
	56	* struct page **pages;
	57	* unsigned int nr_pages;
	58	* unsigned long phys_addr;
	59	* };
	60	*
	61	* get_vm_area() would then call vm_region_alloc with an appropriate
	62	* struct vm_region head (eg):
	63	*
	64	* struct vm_region vmalloc_head = {
	65	* .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list),
	66	* .vm_start = VMALLOC_START,
	67	* .vm_end = VMALLOC_END,
	68	* };
	69	*
	70	* However, vmalloc_head.vm_start is variable (typically, it is dependent on
	71	* the amount of RAM found at boot time.) I would imagine that get_vm_area()
	72	* would have to initialise this each time prior to calling vm_region_alloc().
	73	*/
	74	struct vm_region {
	75	struct list_head vm_list;
	76	unsigned long vm_start;
	77	unsigned long vm_end;
	78	struct page *vm_pages;
5edf71ae	79	int vm_active;
1da177e4 LT	80	};
	81
	82	static struct vm_region consistent_head = {
	83	.vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
	84	.vm_start = CONSISTENT_BASE,
	85	.vm_end = CONSISTENT_END,
	86	};
	87
	88	static struct vm_region *
f9e3214a	89	vm_region_alloc(struct vm_region *head, size_t size, gfp_t gfp)
1da177e4 LT	90	{
	91	unsigned long addr = head->vm_start, end = head->vm_end - size;
	92	unsigned long flags;
	93	struct vm_region c, new;
	94
	95	new = kmalloc(sizeof(struct vm_region), gfp);
	96	if (!new)
	97	goto out;
	98
	99	spin_lock_irqsave(&consistent_lock, flags);
	100
	101	list_for_each_entry(c, &head->vm_list, vm_list) {
	102	if ((addr + size) < addr)
	103	goto nospc;
	104	if ((addr + size) <= c->vm_start)
	105	goto found;
	106	addr = c->vm_end;
	107	if (addr > end)
	108	goto nospc;
	109	}
	110
	111	found:
	112	/*
	113	* Insert this entry _before_ the one we found.
	114	*/
	115	list_add_tail(&new->vm_list, &c->vm_list);
	116	new->vm_start = addr;
	117	new->vm_end = addr + size;
5edf71ae	118	new->vm_active = 1;
1da177e4 LT	119
	120	spin_unlock_irqrestore(&consistent_lock, flags);
	121	return new;
	122
	123	nospc:
	124	spin_unlock_irqrestore(&consistent_lock, flags);
	125	kfree(new);
	126	out:
	127	return NULL;
	128	}
	129
	130	static struct vm_region vm_region_find(struct vm_region head, unsigned long addr)
	131	{
	132	struct vm_region *c;
	133
	134	list_for_each_entry(c, &head->vm_list, vm_list) {
5edf71ae	135	if (c->vm_active && c->vm_start == addr)
1da177e4 LT	136	goto out;
	137	}
	138	c = NULL;
	139	out:
	140	return c;
	141	}
	142
	143	#ifdef CONFIG_HUGETLB_PAGE
	144	#error ARM Coherent DMA allocator does not (yet) support huge TLB
	145	#endif
	146
	147	static void *
f9e3214a	148	__dma_alloc(struct device dev, size_t size, dma_addr_t handle, gfp_t gfp,
1da177e4 LT	149	pgprot_t prot)
	150	{
	151	struct page *page;
	152	struct vm_region *c;
	153	unsigned long order;
	154	u64 mask = ISA_DMA_THRESHOLD, limit;
	155
37134cd5	156	if (!consistent_pte[0]) {
1da177e4 LT	157	printk(KERN_ERR "%s: not initialised\n", __func__);
	158	dump_stack();
	159	return NULL;
	160	}
	161
	162	if (dev) {
	163	mask = dev->coherent_dma_mask;
	164
	165	/*
	166	* Sanity check the DMA mask - it must be non-zero, and
	167	* must be able to be satisfied by a DMA allocation.
	168	*/
	169	if (mask == 0) {
	170	dev_warn(dev, "coherent DMA mask is unset\n");
	171	goto no_page;
	172	}
	173
	174	if ((~mask) & ISA_DMA_THRESHOLD) {
	175	dev_warn(dev, "coherent DMA mask %#llx is smaller "
	176	"than system GFP_DMA mask %#llx\n",
	177	mask, (unsigned long long)ISA_DMA_THRESHOLD);
	178	goto no_page;
	179	}
	180	}
	181
	182	/*
	183	* Sanity check the allocation size.
	184	*/
	185	size = PAGE_ALIGN(size);
	186	limit = (mask + 1) & ~mask;
	187	if ((limit && size >= limit) \|\|
	188	size >= (CONSISTENT_END - CONSISTENT_BASE)) {
	189	printk(KERN_WARNING "coherent allocation too big "
	190	"(requested %#x mask %#llx)\n", size, mask);
	191	goto no_page;
	192	}
	193
	194	order = get_order(size);
	195
	196	if (mask != 0xffffffff)
	197	gfp \|= GFP_DMA;
	198
	199	page = alloc_pages(gfp, order);
	200	if (!page)
	201	goto no_page;
	202
	203	/*
	204	* Invalidate any data that might be lurking in the
	205	* kernel direct-mapped region for device DMA.
	206	*/
	207	{
7ae5a761 RK	208	void *ptr = page_address(page);
	209	memset(ptr, 0, size);
	210	dmac_flush_range(ptr, ptr + size);
	211	outer_flush_range(__pa(ptr), __pa(ptr) + size);
1da177e4 LT	212	}
	213
	214	/*
	215	* Allocate a virtual address in the consistent mapping region.
	216	*/
	217	c = vm_region_alloc(&consistent_head, size,
	218	gfp & ~(__GFP_DMA \| __GFP_HIGHMEM));
	219	if (c) {
37134cd5	220	pte_t *pte;
1da177e4	221	struct page *end = page + (1 << order);
37134cd5 KH	222	int idx = CONSISTENT_PTE_INDEX(c->vm_start);
37134cd5 KH	223	u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
1da177e4	224
37134cd5	225	pte = consistent_pte[idx] + off;
1da177e4 LT	226	c->vm_pages = page;
1da177e4 LT	227
8dfcc9ba NP	228	split_page(page, order);
8dfcc9ba NP	229
1da177e4 LT	230	/*
	231	* Set the "dma handle"
	232	*/
	233	*handle = page_to_dma(dev, page);
	234
	235	do {
	236	BUG_ON(!pte_none(*pte));
	237
1da177e4 LT	238	/*
	239	* x86 does not mark the pages reserved...
	240	*/
	241	SetPageReserved(page);
ad1ae2fe	242	set_pte_ext(pte, mk_pte(page, prot), 0);
1da177e4 LT	243	page++;
1da177e4 LT	244	pte++;
37134cd5 KH	245	off++;
	246	if (off >= PTRS_PER_PTE) {
	247	off = 0;
	248	pte = consistent_pte[++idx];
	249	}
1da177e4 LT	250	} while (size -= PAGE_SIZE);
	251
	252	/*
	253	* Free the otherwise unused pages.
	254	*/
	255	while (page < end) {
1da177e4 LT	256	__free_page(page);
	257	page++;
	258	}
	259
	260	return (void *)c->vm_start;
	261	}
	262
	263	if (page)
	264	__free_pages(page, order);
	265	no_page:
	266	*handle = ~0;
	267	return NULL;
	268	}
	269
	270	/*
	271	* Allocate DMA-coherent memory space and return both the kernel remapped
	272	* virtual and bus address for that space.
	273	*/
	274	void *
f9e3214a	275	dma_alloc_coherent(struct device dev, size_t size, dma_addr_t handle, gfp_t gfp)
1da177e4	276	{
1fe53268 DES	277	void *memory;
	278
	279	if (dma_alloc_from_coherent(dev, size, handle, &memory))
	280	return memory;
	281
23759dc6 LB	282	if (arch_is_coherent()) {
	283	void *virt;
	284
	285	virt = kmalloc(size, gfp);
	286	if (!virt)
	287	return NULL;
	288	*handle = virt_to_dma(dev, virt);
	289
	290	return virt;
	291	}
	292
1da177e4 LT	293	return __dma_alloc(dev, size, handle, gfp,
	294	pgprot_noncached(pgprot_kernel));
	295	}
	296	EXPORT_SYMBOL(dma_alloc_coherent);
	297
	298	/*
	299	* Allocate a writecombining region, in much the same way as
	300	* dma_alloc_coherent above.
	301	*/
	302	void *
f9e3214a	303	dma_alloc_writecombine(struct device dev, size_t size, dma_addr_t handle, gfp_t gfp)
1da177e4 LT	304	{
	305	return __dma_alloc(dev, size, handle, gfp,
	306	pgprot_writecombine(pgprot_kernel));
	307	}
	308	EXPORT_SYMBOL(dma_alloc_writecombine);
	309
	310	static int dma_mmap(struct device dev, struct vm_area_struct vma,
	311	void *cpu_addr, dma_addr_t dma_addr, size_t size)
	312	{
	313	unsigned long flags, user_size, kern_size;
	314	struct vm_region *c;
	315	int ret = -ENXIO;
	316
	317	user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
	318
	319	spin_lock_irqsave(&consistent_lock, flags);
	320	c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
	321	spin_unlock_irqrestore(&consistent_lock, flags);
	322
	323	if (c) {
	324	unsigned long off = vma->vm_pgoff;
	325
	326	kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;
	327
	328	if (off < kern_size &&
	329	user_size <= (kern_size - off)) {
1da177e4 LT	330	ret = remap_pfn_range(vma, vma->vm_start,
	331	page_to_pfn(c->vm_pages) + off,
	332	user_size << PAGE_SHIFT,
	333	vma->vm_page_prot);
	334	}
	335	}
	336
	337	return ret;
	338	}
	339
	340	int dma_mmap_coherent(struct device dev, struct vm_area_struct vma,
	341	void *cpu_addr, dma_addr_t dma_addr, size_t size)
	342	{
	343	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
	344	return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
	345	}
	346	EXPORT_SYMBOL(dma_mmap_coherent);
	347
	348	int dma_mmap_writecombine(struct device dev, struct vm_area_struct vma,
	349	void *cpu_addr, dma_addr_t dma_addr, size_t size)
	350	{
	351	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
	352	return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
	353	}
	354	EXPORT_SYMBOL(dma_mmap_writecombine);
	355
	356	/*
	357	* free a page as defined by the above mapping.
5edf71ae	358	* Must not be called with IRQs disabled.
1da177e4 LT	359	*/
	360	void dma_free_coherent(struct device dev, size_t size, void cpu_addr, dma_addr_t handle)
	361	{
	362	struct vm_region *c;
	363	unsigned long flags, addr;
	364	pte_t *ptep;
37134cd5 KH	365	int idx;
37134cd5 KH	366	u32 off;
1da177e4	367
5edf71ae RK	368	WARN_ON(irqs_disabled());
5edf71ae RK	369
1fe53268 DES	370	if (dma_release_from_coherent(dev, get_order(size), cpu_addr))
	371	return;
	372
23759dc6 LB	373	if (arch_is_coherent()) {
	374	kfree(cpu_addr);
	375	return;
	376	}
	377
1da177e4 LT	378	size = PAGE_ALIGN(size);
	379
	380	spin_lock_irqsave(&consistent_lock, flags);
1da177e4 LT	381	c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
	382	if (!c)
	383	goto no_area;
	384
5edf71ae RK	385	c->vm_active = 0;
	386	spin_unlock_irqrestore(&consistent_lock, flags);
	387
1da177e4 LT	388	if ((c->vm_end - c->vm_start) != size) {
	389	printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
	390	__func__, c->vm_end - c->vm_start, size);
	391	dump_stack();
	392	size = c->vm_end - c->vm_start;
	393	}
	394
37134cd5 KH	395	idx = CONSISTENT_PTE_INDEX(c->vm_start);
	396	off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
	397	ptep = consistent_pte[idx] + off;
1da177e4 LT	398	addr = c->vm_start;
	399	do {
	400	pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
	401	unsigned long pfn;
	402
	403	ptep++;
	404	addr += PAGE_SIZE;
37134cd5 KH	405	off++;
	406	if (off >= PTRS_PER_PTE) {
	407	off = 0;
	408	ptep = consistent_pte[++idx];
	409	}
1da177e4 LT	410
	411	if (!pte_none(pte) && pte_present(pte)) {
	412	pfn = pte_pfn(pte);
	413
	414	if (pfn_valid(pfn)) {
	415	struct page *page = pfn_to_page(pfn);
	416
	417	/*
	418	* x86 does not mark the pages reserved...
	419	*/
	420	ClearPageReserved(page);
	421
	422	__free_page(page);
	423	continue;
	424	}
	425	}
	426
	427	printk(KERN_CRIT "%s: bad page in kernel page table\n",
	428	__func__);
	429	} while (size -= PAGE_SIZE);
	430
	431	flush_tlb_kernel_range(c->vm_start, c->vm_end);
	432
5edf71ae	433	spin_lock_irqsave(&consistent_lock, flags);
1da177e4	434	list_del(&c->vm_list);
1da177e4 LT	435	spin_unlock_irqrestore(&consistent_lock, flags);
	436
	437	kfree(c);
	438	return;
	439
	440	no_area:
	441	spin_unlock_irqrestore(&consistent_lock, flags);
	442	printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
	443	__func__, cpu_addr);
	444	dump_stack();
	445	}
	446	EXPORT_SYMBOL(dma_free_coherent);
	447
	448	/*
	449	* Initialise the consistent memory allocation.
	450	*/
	451	static int __init consistent_init(void)
	452	{
	453	pgd_t *pgd;
	454	pmd_t *pmd;
	455	pte_t *pte;
37134cd5 KH	456	int ret = 0, i = 0;
37134cd5 KH	457	u32 base = CONSISTENT_BASE;
1da177e4	458
1da177e4	459	do {
37134cd5 KH	460	pgd = pgd_offset(&init_mm, base);
37134cd5 KH	461	pmd = pmd_alloc(&init_mm, pgd, base);
1da177e4 LT	462	if (!pmd) {
	463	printk(KERN_ERR "%s: no pmd tables\n", __func__);
	464	ret = -ENOMEM;
	465	break;
	466	}
	467	WARN_ON(!pmd_none(*pmd));
	468
37134cd5	469	pte = pte_alloc_kernel(pmd, base);
1da177e4 LT	470	if (!pte) {
	471	printk(KERN_ERR "%s: no pte tables\n", __func__);
	472	ret = -ENOMEM;
	473	break;
	474	}
	475
37134cd5 KH	476	consistent_pte[i++] = pte;
	477	base += (1 << PGDIR_SHIFT);
	478	} while (base < CONSISTENT_END);
1da177e4	479
1da177e4 LT	480	return ret;
	481	}
	482
	483	core_initcall(consistent_init);
	484
	485	/*
	486	* Make an area consistent for devices.
105ef9a0 DW	487	* Note: Drivers should NOT use this function directly, as it will break
	488	* platforms with CONFIG_DMABOUNCE.
	489	* Use the driver DMA support - see dma-mapping.h (dma_sync_*)
1da177e4	490	*/
84aa462e	491	void dma_cache_maint(const void *start, size_t size, int direction)
1da177e4	492	{
7ae5a761	493	const void *end = start + size;
1da177e4	494
3e1a80f1	495	BUG_ON(!virt_addr_valid(start) \|\| !virt_addr_valid(end - 1));
953233dc	496
1da177e4 LT	497	switch (direction) {
	498	case DMA_FROM_DEVICE: /* invalidate only */
	499	dmac_inv_range(start, end);
953233dc	500	outer_inv_range(__pa(start), __pa(end));
1da177e4 LT	501	break;
	502	case DMA_TO_DEVICE: /* writeback only */
	503	dmac_clean_range(start, end);
953233dc	504	outer_clean_range(__pa(start), __pa(end));
1da177e4 LT	505	break;
	506	case DMA_BIDIRECTIONAL: /* writeback and invalidate */
	507	dmac_flush_range(start, end);
953233dc	508	outer_flush_range(__pa(start), __pa(end));
1da177e4 LT	509	break;
	510	default:
	511	BUG();
	512	}
	513	}
84aa462e	514	EXPORT_SYMBOL(dma_cache_maint);