[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / powerpc / mm / dma-noncoherent.c

/*
 *  PowerPC version derived from arch/arm/mm/consistent.c
 *    Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
 *
 *  Copyright (C) 2000 Russell King
 *
 * Consistent memory allocators.  Used for DMA devices that want to
 * share uncached memory with the processor core.  The function return
 * is the virtual address and 'dma_handle' is the physical address.
 * Mostly stolen from the ARM port, with some changes for PowerPC.
 *						-- Dan
 *
 * Reorganized to get rid of the arch-specific consistent_* functions
 * and provide non-coherent implementations for the DMA API. -Matt
 *
 * Added in_interrupt() safe dma_alloc_coherent()/dma_free_coherent()
 * implementation. This is pulled straight from ARM and barely
 * modified. -Matt
 *
 * 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.
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/highmem.h>
#include <linux/dma-mapping.h>
#include <linux/export.h>

#include <asm/tlbflush.h>

#include "mmu_decl.h"

/*
 * This address range defaults to a value that is safe for all
 * platforms which currently set CONFIG_NOT_COHERENT_CACHE. It
 * can be further configured for specific applications under
 * the "Advanced Setup" menu. -Matt
 */
#define CONSISTENT_BASE		(IOREMAP_TOP)
#define CONSISTENT_END 		(CONSISTENT_BASE + CONFIG_CONSISTENT_SIZE)
#define CONSISTENT_OFFSET(x)	(((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)

/*
 * This is the page table (2MB) covering uncached, DMA consistent allocations
 */
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 ppc_vm_region {
	struct list_head	vm_list;
	unsigned long		vm_start;
	unsigned long		vm_end;
};

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

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

	new = kmalloc(sizeof(struct ppc_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;

	spin_unlock_irqrestore(&consistent_lock, flags);
	return new;

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

static struct ppc_vm_region *ppc_vm_region_find(struct ppc_vm_region *head, unsigned long addr)
{
	struct ppc_vm_region *c;

	list_for_each_entry(c, &head->vm_list, vm_list) {
		if (c->vm_start == addr)
			goto out;
	}
	c = NULL;
 out:
	return c;
}

/*
 * 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)
{
	struct page *page;
	struct ppc_vm_region *c;
	unsigned long order;
	u64 mask = ISA_DMA_THRESHOLD, limit;

	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;
		}
	}


	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 %#Lx)\n",
		       size, mask);
		return NULL;
	}

	order = get_order(size);

	/* Might be useful if we ever have a real legacy DMA zone... */
	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.
	 */
	{
		unsigned long kaddr = (unsigned long)page_address(page);
		memset(page_address(page), 0, size);
		flush_dcache_range(kaddr, kaddr + size);
	}

	/*
	 * Allocate a virtual address in the consistent mapping region.
	 */
	c = ppc_vm_region_alloc(&consistent_head, size,
			    gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
	if (c) {
		unsigned long vaddr = c->vm_start;
		struct page *end = page + (1 << order);

		split_page(page, order);

		/*
		 * Set the "dma handle"
		 */
		*handle = page_to_phys(page);

		do {
			SetPageReserved(page);
			map_page(vaddr, page_to_phys(page),
				 pgprot_noncached(PAGE_KERNEL));
			page++;
			vaddr += PAGE_SIZE;
		} 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:
	return NULL;
}
EXPORT_SYMBOL(__dma_alloc_coherent);

/*
 * free a page as defined by the above mapping.
 */
void __dma_free_coherent(size_t size, void *vaddr)
{
	struct ppc_vm_region *c;
	unsigned long flags, addr;
	
	size = PAGE_ALIGN(size);

	spin_lock_irqsave(&consistent_lock, flags);

	c = ppc_vm_region_find(&consistent_head, (unsigned long)vaddr);
	if (!c)
		goto no_area;

	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;
	}

	addr = c->vm_start;
	do {
		pte_t *ptep;
		unsigned long pfn;

		ptep = pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(addr),
							       addr),
						    addr),
					 addr);
		if (!pte_none(*ptep) && pte_present(*ptep)) {
			pfn = pte_pfn(*ptep);
			pte_clear(&init_mm, addr, ptep);
			if (pfn_valid(pfn)) {
				struct page *page = pfn_to_page(pfn);

				ClearPageReserved(page);
				__free_page(page);
			}
		}
		addr += PAGE_SIZE;
	} while (size -= PAGE_SIZE);

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

	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__, vaddr);
	dump_stack();
}
EXPORT_SYMBOL(__dma_free_coherent);

/*
 * make an area consistent.
 */
void __dma_sync(void *vaddr, size_t size, int direction)
{
	unsigned long start = (unsigned long)vaddr;
	unsigned long end   = start + size;

	switch (direction) {
	case DMA_NONE:
		BUG();
	case DMA_FROM_DEVICE:
		/*
		 * invalidate only when cache-line aligned otherwise there is
		 * the potential for discarding uncommitted data from the cache
		 */
		if ((start & (L1_CACHE_BYTES - 1)) || (size & (L1_CACHE_BYTES - 1)))
			flush_dcache_range(start, end);
		else
			invalidate_dcache_range(start, end);
		break;
	case DMA_TO_DEVICE:		/* writeback only */
		clean_dcache_range(start, end);
		break;
	case DMA_BIDIRECTIONAL:	/* writeback and invalidate */
		flush_dcache_range(start, end);
		break;
	}
}
EXPORT_SYMBOL(__dma_sync);

#ifdef CONFIG_HIGHMEM
/*
 * __dma_sync_page() implementation for systems using highmem.
 * In this case, each page of a buffer must be kmapped/kunmapped
 * in order to have a virtual address for __dma_sync(). This must
 * not sleep so kmap_atomic()/kunmap_atomic() are used.
 *
 * Note: yes, it is possible and correct to have a buffer extend
 * beyond the first page.
 */
static inline void __dma_sync_page_highmem(struct page *page,
		unsigned long offset, size_t size, int direction)
{
	size_t seg_size = min((size_t)(PAGE_SIZE - offset), size);
	size_t cur_size = seg_size;
	unsigned long flags, start, seg_offset = offset;
	int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE;
	int seg_nr = 0;

	local_irq_save(flags);

	do {
		start = (unsigned long)kmap_atomic(page + seg_nr) + seg_offset;

		/* Sync this buffer segment */
		__dma_sync((void *)start, seg_size, direction);
		kunmap_atomic((void *)start);
		seg_nr++;

		/* Calculate next buffer segment size */
		seg_size = min((size_t)PAGE_SIZE, size - cur_size);

		/* Add the segment size to our running total */
		cur_size += seg_size;
		seg_offset = 0;
	} while (seg_nr < nr_segs);

	local_irq_restore(flags);
}
#endif /* CONFIG_HIGHMEM */

/*
 * __dma_sync_page makes memory consistent. identical to __dma_sync, but
 * takes a struct page instead of a virtual address
 */
void __dma_sync_page(struct page *page, unsigned long offset,
	size_t size, int direction)
{
#ifdef CONFIG_HIGHMEM
	__dma_sync_page_highmem(page, offset, size, direction);
#else
	unsigned long start = (unsigned long)page_address(page) + offset;
	__dma_sync((void *)start, size, direction);
#endif
}
EXPORT_SYMBOL(__dma_sync_page);

/*
 * Return the PFN for a given cpu virtual address returned by
 * __dma_alloc_coherent. This is used by dma_mmap_coherent()
 */
unsigned long __dma_get_coherent_pfn(unsigned long cpu_addr)
{
	/* This should always be populated, so we don't test every
	 * level. If that fails, we'll have a nice crash which
	 * will be as good as a BUG_ON()
	 */
	pgd_t *pgd = pgd_offset_k(cpu_addr);
	pud_t *pud = pud_offset(pgd, cpu_addr);
	pmd_t *pmd = pmd_offset(pud, cpu_addr);
	pte_t *ptep = pte_offset_kernel(pmd, cpu_addr);

	if (pte_none(*ptep) || !pte_present(*ptep))
		return 0;
	return pte_pfn(*ptep);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* PowerPC version derived from arch/arm/mm/consistent.c
	3	* Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
	4	*
	5	* Copyright (C) 2000 Russell King
	6	*
	7	* Consistent memory allocators. Used for DMA devices that want to
	8	* share uncached memory with the processor core. The function return
	9	* is the virtual address and 'dma_handle' is the physical address.
	10	* Mostly stolen from the ARM port, with some changes for PowerPC.
	11	* -- Dan
	12	*
	13	* Reorganized to get rid of the arch-specific consistent_* functions
	14	* and provide non-coherent implementations for the DMA API. -Matt
	15	*
	16	* Added in_interrupt() safe dma_alloc_coherent()/dma_free_coherent()
	17	* implementation. This is pulled straight from ARM and barely
	18	* modified. -Matt
	19	*
	20	* This program is free software; you can redistribute it and/or modify
	21	* it under the terms of the GNU General Public License version 2 as
	22	* published by the Free Software Foundation.
	23	*/
	24
1da177e4	25	#include <linux/sched.h>
5a0e3ad6	26	#include <linux/slab.h>
1da177e4 LT	27	#include <linux/kernel.h>
	28	#include <linux/errno.h>
	29	#include <linux/string.h>
	30	#include <linux/types.h>
1da177e4 LT	31	#include <linux/highmem.h>
1da177e4 LT	32	#include <linux/dma-mapping.h>
93087948	33	#include <linux/export.h>
1da177e4 LT	34
	35	#include <asm/tlbflush.h>
	36
8b31e49d BH	37	#include "mmu_decl.h"
8b31e49d BH	38
84532a0f BH	39	/*
	40	* This address range defaults to a value that is safe for all
	41	* platforms which currently set CONFIG_NOT_COHERENT_CACHE. It
	42	* can be further configured for specific applications under
	43	* the "Advanced Setup" menu. -Matt
	44	*/
8b31e49d BH	45	#define CONSISTENT_BASE (IOREMAP_TOP)
8b31e49d BH	46	#define CONSISTENT_END (CONSISTENT_BASE + CONFIG_CONSISTENT_SIZE)
84532a0f BH	47	#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)
	48
	49	/*
	50	* This is the page table (2MB) covering uncached, DMA consistent allocations
	51	*/
84532a0f BH	52	static DEFINE_SPINLOCK(consistent_lock);
	53
	54	/*
	55	* VM region handling support.
	56	*
	57	* This should become something generic, handling VM region allocations for
	58	* vmalloc and similar (ioremap, module space, etc).
	59	*
	60	* I envisage vmalloc()'s supporting vm_struct becoming:
	61	*
	62	* struct vm_struct {
	63	* struct vm_region region;
	64	* unsigned long flags;
	65	* struct page **pages;
	66	* unsigned int nr_pages;
	67	* unsigned long phys_addr;
	68	* };
	69	*
	70	* get_vm_area() would then call vm_region_alloc with an appropriate
	71	* struct vm_region head (eg):
	72	*
	73	* struct vm_region vmalloc_head = {
	74	* .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list),
	75	* .vm_start = VMALLOC_START,
	76	* .vm_end = VMALLOC_END,
	77	* };
	78	*
	79	* However, vmalloc_head.vm_start is variable (typically, it is dependent on
	80	* the amount of RAM found at boot time.) I would imagine that get_vm_area()
	81	* would have to initialise this each time prior to calling vm_region_alloc().
	82	*/
	83	struct ppc_vm_region {
	84	struct list_head vm_list;
	85	unsigned long vm_start;
	86	unsigned long vm_end;
	87	};
	88
	89	static struct ppc_vm_region consistent_head = {
	90	.vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
	91	.vm_start = CONSISTENT_BASE,
	92	.vm_end = CONSISTENT_END,
	93	};
	94
	95	static struct ppc_vm_region *
	96	ppc_vm_region_alloc(struct ppc_vm_region *head, size_t size, gfp_t gfp)
	97	{
	98	unsigned long addr = head->vm_start, end = head->vm_end - size;
	99	unsigned long flags;
	100	struct ppc_vm_region c, new;
	101
	102	new = kmalloc(sizeof(struct ppc_vm_region), gfp);
	103	if (!new)
	104	goto out;
	105
	106	spin_lock_irqsave(&consistent_lock, flags);
	107
	108	list_for_each_entry(c, &head->vm_list, vm_list) {
	109	if ((addr + size) < addr)
	110	goto nospc;
	111	if ((addr + size) <= c->vm_start)
	112	goto found;
	113	addr = c->vm_end;
	114	if (addr > end)
	115	goto nospc;
116	}
117
118	found:
119	/*
120	* Insert this entry _before_ the one we found.
121	*/
122	list_add_tail(&new->vm_list, &c->vm_list);
123	new->vm_start = addr;
124	new->vm_end = addr + size;
125
126	spin_unlock_irqrestore(&consistent_lock, flags);
127	return new;
128
129	nospc:
130	spin_unlock_irqrestore(&consistent_lock, flags);
131	kfree(new);
132	out:
133	return NULL;
134	}
135
136	static struct ppc_vm_region ppc_vm_region_find(struct ppc_vm_region head, unsigned long addr)
137	{
138	struct ppc_vm_region *c;
139
140	list_for_each_entry(c, &head->vm_list, vm_list) {
141	if (c->vm_start == addr)
142	goto out;
143	}
144	c = NULL;
145	out:
146	return c;
147	}
148
1da177e4 LT	149	/*
	150	* Allocate DMA-coherent memory space and return both the kernel remapped
	151	* virtual and bus address for that space.
	152	*/
	153	void *
8b31e49d	154	__dma_alloc_coherent(struct device dev, size_t size, dma_addr_t handle, gfp_t gfp)
1da177e4 LT	155	{
1da177e4 LT	156	struct page *page;
84532a0f	157	struct ppc_vm_region *c;
1da177e4	158	unsigned long order;
8b31e49d	159	u64 mask = ISA_DMA_THRESHOLD, limit;
1da177e4	160
8b31e49d BH	161	if (dev) {
	162	mask = dev->coherent_dma_mask;
	163
	164	/*
	165	* Sanity check the DMA mask - it must be non-zero, and
	166	* must be able to be satisfied by a DMA allocation.
	167	*/
	168	if (mask == 0) {
	169	dev_warn(dev, "coherent DMA mask is unset\n");
	170	goto no_page;
	171	}
	172
	173	if ((~mask) & ISA_DMA_THRESHOLD) {
	174	dev_warn(dev, "coherent DMA mask %#llx is smaller "
	175	"than system GFP_DMA mask %#llx\n",
	176	mask, (unsigned long long)ISA_DMA_THRESHOLD);
	177	goto no_page;
	178	}
84532a0f BH	179	}
84532a0f BH	180
8b31e49d	181
1da177e4 LT	182	size = PAGE_ALIGN(size);
1da177e4 LT	183	limit = (mask + 1) & ~mask;
8b31e49d BH	184	if ((limit && size >= limit) \|\|
8b31e49d BH	185	size >= (CONSISTENT_END - CONSISTENT_BASE)) {
84532a0f BH	186	printk(KERN_WARNING "coherent allocation too big (requested %#x mask %#Lx)\n",
84532a0f BH	187	size, mask);
1da177e4 LT	188	return NULL;
	189	}
	190
	191	order = get_order(size);
	192
8b31e49d	193	/* Might be useful if we ever have a real legacy DMA zone... */
1da177e4 LT	194	if (mask != 0xffffffff)
	195	gfp \|= GFP_DMA;
	196
	197	page = alloc_pages(gfp, order);
	198	if (!page)
	199	goto no_page;
	200
	201	/*
	202	* Invalidate any data that might be lurking in the
	203	* kernel direct-mapped region for device DMA.
	204	*/
	205	{
	206	unsigned long kaddr = (unsigned long)page_address(page);
	207	memset(page_address(page), 0, size);
	208	flush_dcache_range(kaddr, kaddr + size);
	209	}
	210
	211	/*
84532a0f	212	* Allocate a virtual address in the consistent mapping region.
1da177e4	213	*/
84532a0f BH	214	c = ppc_vm_region_alloc(&consistent_head, size,
	215	gfp & ~(__GFP_DMA \| __GFP_HIGHMEM));
	216	if (c) {
	217	unsigned long vaddr = c->vm_start;
84532a0f	218	struct page *end = page + (1 << order);
1da177e4	219
84532a0f BH	220	split_page(page, order);
	221
	222	/*
	223	* Set the "dma handle"
	224	*/
	225	*handle = page_to_phys(page);
1da177e4	226
84532a0f	227	do {
84532a0f	228	SetPageReserved(page);
8b31e49d BH	229	map_page(vaddr, page_to_phys(page),
8b31e49d BH	230	pgprot_noncached(PAGE_KERNEL));
84532a0f	231	page++;
84532a0f BH	232	vaddr += PAGE_SIZE;
84532a0f BH	233	} while (size -= PAGE_SIZE);
1da177e4	234
84532a0f BH	235	/*
	236	* Free the otherwise unused pages.
	237	*/
	238	while (page < end) {
	239	__free_page(page);
	240	page++;
	241	}
	242
	243	return (void *)c->vm_start;
1da177e4 LT	244	}
	245
	246	if (page)
	247	__free_pages(page, order);
84532a0f	248	no_page:
1da177e4 LT	249	return NULL;
	250	}
	251	EXPORT_SYMBOL(__dma_alloc_coherent);
	252
	253	/*
	254	* free a page as defined by the above mapping.
	255	*/
	256	void __dma_free_coherent(size_t size, void *vaddr)
	257	{
84532a0f BH	258	struct ppc_vm_region *c;
84532a0f BH	259	unsigned long flags, addr;
8b31e49d	260
84532a0f BH	261	size = PAGE_ALIGN(size);
	262
	263	spin_lock_irqsave(&consistent_lock, flags);
	264
	265	c = ppc_vm_region_find(&consistent_head, (unsigned long)vaddr);
	266	if (!c)
	267	goto no_area;
	268
	269	if ((c->vm_end - c->vm_start) != size) {
	270	printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
	271	__func__, c->vm_end - c->vm_start, size);
	272	dump_stack();
	273	size = c->vm_end - c->vm_start;
	274	}
	275
84532a0f BH	276	addr = c->vm_start;
84532a0f BH	277	do {
8b31e49d	278	pte_t *ptep;
84532a0f BH	279	unsigned long pfn;
84532a0f BH	280
8b31e49d BH	281	ptep = pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(addr),
	282	addr),
	283	addr),
	284	addr);
	285	if (!pte_none(ptep) && pte_present(ptep)) {
	286	pfn = pte_pfn(*ptep);
	287	pte_clear(&init_mm, addr, ptep);
84532a0f BH	288	if (pfn_valid(pfn)) {
84532a0f BH	289	struct page *page = pfn_to_page(pfn);
84532a0f	290
8b31e49d	291	ClearPageReserved(page);
84532a0f	292	__free_page(page);
84532a0f BH	293	}
84532a0f BH	294	}
8b31e49d	295	addr += PAGE_SIZE;
84532a0f BH	296	} while (size -= PAGE_SIZE);
	297
	298	flush_tlb_kernel_range(c->vm_start, c->vm_end);
	299
	300	list_del(&c->vm_list);
	301
	302	spin_unlock_irqrestore(&consistent_lock, flags);
	303
	304	kfree(c);
	305	return;
	306
	307	no_area:
	308	spin_unlock_irqrestore(&consistent_lock, flags);
	309	printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
	310	__func__, vaddr);
	311	dump_stack();
1da177e4 LT	312	}
	313	EXPORT_SYMBOL(__dma_free_coherent);
	314
1da177e4 LT	315	/*
	316	* make an area consistent.
	317	*/
	318	void __dma_sync(void *vaddr, size_t size, int direction)
	319	{
	320	unsigned long start = (unsigned long)vaddr;
	321	unsigned long end = start + size;
	322
	323	switch (direction) {
	324	case DMA_NONE:
	325	BUG();
03d70617 AL	326	case DMA_FROM_DEVICE:
	327	/*
	328	* invalidate only when cache-line aligned otherwise there is
	329	* the potential for discarding uncommitted data from the cache
	330	*/
	331	if ((start & (L1_CACHE_BYTES - 1)) \|\| (size & (L1_CACHE_BYTES - 1)))
	332	flush_dcache_range(start, end);
	333	else
	334	invalidate_dcache_range(start, end);
1da177e4 LT	335	break;
	336	case DMA_TO_DEVICE: /* writeback only */
	337	clean_dcache_range(start, end);
	338	break;
	339	case DMA_BIDIRECTIONAL: /* writeback and invalidate */
	340	flush_dcache_range(start, end);
	341	break;
	342	}
	343	}
	344	EXPORT_SYMBOL(__dma_sync);
	345
	346	#ifdef CONFIG_HIGHMEM
	347	/*
	348	* __dma_sync_page() implementation for systems using highmem.
	349	* In this case, each page of a buffer must be kmapped/kunmapped
	350	* in order to have a virtual address for __dma_sync(). This must
338cec32	351	* not sleep so kmap_atomic()/kunmap_atomic() are used.
1da177e4 LT	352	*
	353	* Note: yes, it is possible and correct to have a buffer extend
	354	* beyond the first page.
	355	*/
	356	static inline void __dma_sync_page_highmem(struct page *page,
	357	unsigned long offset, size_t size, int direction)
	358	{
a0c111c6	359	size_t seg_size = min((size_t)(PAGE_SIZE - offset), size);
1da177e4 LT	360	size_t cur_size = seg_size;
1da177e4 LT	361	unsigned long flags, start, seg_offset = offset;
a0c111c6	362	int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE;
1da177e4 LT	363	int seg_nr = 0;
	364
	365	local_irq_save(flags);
	366
	367	do {
2480b208	368	start = (unsigned long)kmap_atomic(page + seg_nr) + seg_offset;
1da177e4 LT	369
	370	/* Sync this buffer segment */
	371	__dma_sync((void *)start, seg_size, direction);
2480b208	372	kunmap_atomic((void *)start);
1da177e4 LT	373	seg_nr++;
	374
	375	/* Calculate next buffer segment size */
	376	seg_size = min((size_t)PAGE_SIZE, size - cur_size);
	377
	378	/* Add the segment size to our running total */
	379	cur_size += seg_size;
	380	seg_offset = 0;
	381	} while (seg_nr < nr_segs);
	382
	383	local_irq_restore(flags);
	384	}
	385	#endif /* CONFIG_HIGHMEM */
	386
	387	/*
	388	* __dma_sync_page makes memory consistent. identical to __dma_sync, but
	389	* takes a struct page instead of a virtual address
	390	*/
	391	void __dma_sync_page(struct page *page, unsigned long offset,
	392	size_t size, int direction)
	393	{
	394	#ifdef CONFIG_HIGHMEM
	395	__dma_sync_page_highmem(page, offset, size, direction);
	396	#else
	397	unsigned long start = (unsigned long)page_address(page) + offset;
	398	__dma_sync((void *)start, size, direction);
	399	#endif
	400	}
	401	EXPORT_SYMBOL(__dma_sync_page);
6090912c BH	402
	403	/*
	404	* Return the PFN for a given cpu virtual address returned by
	405	* __dma_alloc_coherent. This is used by dma_mmap_coherent()
	406	*/
	407	unsigned long __dma_get_coherent_pfn(unsigned long cpu_addr)
	408	{
	409	/* This should always be populated, so we don't test every
	410	* level. If that fails, we'll have a nice crash which
	411	* will be as good as a BUG_ON()
	412	*/
	413	pgd_t *pgd = pgd_offset_k(cpu_addr);
	414	pud_t *pud = pud_offset(pgd, cpu_addr);
	415	pmd_t *pmd = pmd_offset(pud, cpu_addr);
	416	pte_t *ptep = pte_offset_kernel(pmd, cpu_addr);
	417
	418	if (pte_none(ptep) \|\| !pte_present(ptep))
	419	return 0;
	420	return pte_pfn(*ptep);
	421	}