arch/mips/mm/dma-default.c - kernel/common - Git at Google

 /*
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
  * Copyright (C) 2000  Ani Joshi <[email protected]>
  * Copyright (C) 2000, 2001, 06	 Ralf Baechle <[email protected]>
  * swiped from i386, and cloned for MIPS by Geert, polished by Ralf.
  */

 #include <linux/types.h>
 #include <linux/dma-mapping.h>
 #include <linux/mm.h>
 #include <linux/export.h>
 #include <linux/scatterlist.h>
 #include <linux/string.h>
 #include <linux/gfp.h>
 #include <linux/highmem.h>
 #include <linux/dma-contiguous.h>

 #include <asm/cache.h>
 #include <asm/cpu-type.h>
 #include <asm/io.h>

 #include <dma-coherence.h>

 #if defined(CONFIG_DMA_MAYBE_COHERENT) && !defined(CONFIG_DMA_PERDEV_COHERENT)
 /* User defined DMA coherency from command line. */
 enum coherent_io_user_state coherentio = IO_COHERENCE_DEFAULT;
 EXPORT_SYMBOL_GPL(coherentio);
 int hw_coherentio = 0;	/* Actual hardware supported DMA coherency setting. */

 static int __init setcoherentio(char *str)
 {
 	coherentio = IO_COHERENCE_ENABLED;
 	pr_info("Hardware DMA cache coherency (command line)\n");
 	return 0;
 }
 early_param("coherentio", setcoherentio);

 static int __init setnocoherentio(char *str)
 {
 	coherentio = IO_COHERENCE_DISABLED;
 	pr_info("Software DMA cache coherency (command line)\n");
 	return 0;
 }
 early_param("nocoherentio", setnocoherentio);
 #endif

 static inline struct page *dma_addr_to_page(struct device *dev,
 	dma_addr_t dma_addr)
 {
 	return pfn_to_page(
 		plat_dma_addr_to_phys(dev, dma_addr) >> PAGE_SHIFT);
 }

 /*
  * The affected CPUs below in 'cpu_needs_post_dma_flush()' can
  * speculatively fill random cachelines with stale data at any time,
  * requiring an extra flush post-DMA.
  *
  * Warning on the terminology - Linux calls an uncached area coherent;
  * MIPS terminology calls memory areas with hardware maintained coherency
  * coherent.
  *
  * Note that the R14000 and R16000 should also be checked for in this
  * condition.  However this function is only called on non-I/O-coherent
  * systems and only the R10000 and R12000 are used in such systems, the
  * SGI IP28 Indigo² rsp. SGI IP32 aka O2.
  */
 static inline bool cpu_needs_post_dma_flush(struct device *dev)
 {
 	if (plat_device_is_coherent(dev))
 		return false;

 	switch (boot_cpu_type()) {
 	case CPU_R10000:
 	case CPU_R12000:
 	case CPU_BMIPS5000:
 		return true;

 	default:
 		/*
 		 * Presence of MAARs suggests that the CPU supports
 		 * speculatively prefetching data, and therefore requires
 		 * the post-DMA flush/invalidate.
 		 */
 		return cpu_has_maar;
 	}
 }

 static gfp_t massage_gfp_flags(const struct device *dev, gfp_t gfp)
 {
 	gfp_t dma_flag;

 	/* ignore region specifiers */
 	gfp &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM);

 #ifdef CONFIG_ISA
 	if (dev == NULL)
 		dma_flag = __GFP_DMA;
 	else
 #endif
 #if defined(CONFIG_ZONE_DMA32) && defined(CONFIG_ZONE_DMA)
 	     if (dev == NULL || dev->coherent_dma_mask < DMA_BIT_MASK(32))
 			dma_flag = __GFP_DMA;
 	else if (dev->coherent_dma_mask < DMA_BIT_MASK(64))
 			dma_flag = __GFP_DMA32;
 	else
 #endif
 #if defined(CONFIG_ZONE_DMA32) && !defined(CONFIG_ZONE_DMA)
 	     if (dev == NULL || dev->coherent_dma_mask < DMA_BIT_MASK(64))
 		dma_flag = __GFP_DMA32;
 	else
 #endif
 #if defined(CONFIG_ZONE_DMA) && !defined(CONFIG_ZONE_DMA32)
 	     if (dev == NULL ||
 		 dev->coherent_dma_mask < DMA_BIT_MASK(sizeof(phys_addr_t) * 8))
 		dma_flag = __GFP_DMA;
 	else
 #endif
 		dma_flag = 0;

 	/* Don't invoke OOM killer */
 	gfp |= __GFP_NORETRY;

 	return gfp | dma_flag;
 }

 static void *mips_dma_alloc_noncoherent(struct device *dev, size_t size,
 	dma_addr_t * dma_handle, gfp_t gfp)
 {
 	void *ret;

 	gfp = massage_gfp_flags(dev, gfp);

 	ret = (void *) __get_free_pages(gfp, get_order(size));

 	if (ret != NULL) {
 		memset(ret, 0, size);
 		*dma_handle = plat_map_dma_mem(dev, ret, size);
 	}

 	return ret;
 }

 static void *mips_dma_alloc_coherent(struct device *dev, size_t size,
 	dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
 {
 	void *ret;
 	struct page *page = NULL;
 	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;

 	/*
 	 * XXX: seems like the coherent and non-coherent implementations could
 	 * be consolidated.
 	 */
 	if (attrs & DMA_ATTR_NON_CONSISTENT)
 		return mips_dma_alloc_noncoherent(dev, size, dma_handle, gfp);

 	gfp = massage_gfp_flags(dev, gfp);

 	if (IS_ENABLED(CONFIG_DMA_CMA) && gfpflags_allow_blocking(gfp))
 		page = dma_alloc_from_contiguous(dev, count, get_order(size),
 						 gfp);
 	if (!page)
 		page = alloc_pages(gfp, get_order(size));

 	if (!page)
 		return NULL;

 	ret = page_address(page);
 	memset(ret, 0, size);
 	*dma_handle = plat_map_dma_mem(dev, ret, size);
 	if (!plat_device_is_coherent(dev)) {
 		dma_cache_wback_inv((unsigned long) ret, size);
 		ret = UNCAC_ADDR(ret);
 	}

 	return ret;
 }


 static void mips_dma_free_noncoherent(struct device *dev, size_t size,
 		void *vaddr, dma_addr_t dma_handle)
 {
 	plat_unmap_dma_mem(dev, dma_handle, size, DMA_BIDIRECTIONAL);
 	free_pages((unsigned long) vaddr, get_order(size));
 }

 static void mips_dma_free_coherent(struct device *dev, size_t size, void *vaddr,
 	dma_addr_t dma_handle, unsigned long attrs)
 {
 	unsigned long addr = (unsigned long) vaddr;
 	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	struct page *page = NULL;

 	if (attrs & DMA_ATTR_NON_CONSISTENT) {
 		mips_dma_free_noncoherent(dev, size, vaddr, dma_handle);
 		return;
 	}

 	plat_unmap_dma_mem(dev, dma_handle, size, DMA_BIDIRECTIONAL);

 	if (!plat_device_is_coherent(dev))
 		addr = CAC_ADDR(addr);

 	page = virt_to_page((void *) addr);

 	if (!dma_release_from_contiguous(dev, page, count))
 		__free_pages(page, get_order(size));
 }

 static int mips_dma_mmap(struct device *dev, struct vm_area_struct *vma,
 	void *cpu_addr, dma_addr_t dma_addr, size_t size,
 	unsigned long attrs)
 {
 	unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	unsigned long addr = (unsigned long)cpu_addr;
 	unsigned long off = vma->vm_pgoff;
 	unsigned long pfn;
 	int ret = -ENXIO;

 	if (!plat_device_is_coherent(dev))
 		addr = CAC_ADDR(addr);

 	pfn = page_to_pfn(virt_to_page((void *)addr));

 	if (attrs & DMA_ATTR_WRITE_COMBINE)
 		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
 	else
 		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

 	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
 		return ret;

 	if (off < count && user_count <= (count - off)) {
 		ret = remap_pfn_range(vma, vma->vm_start,
 				      pfn + off,
 				      user_count << PAGE_SHIFT,
 				      vma->vm_page_prot);
 	}

 	return ret;
 }

 static inline void __dma_sync_virtual(void *addr, size_t size,
 	enum dma_data_direction direction)
 {
 	switch (direction) {
 	case DMA_TO_DEVICE:
 		dma_cache_wback((unsigned long)addr, size);
 		break;

 	case DMA_FROM_DEVICE:
 		dma_cache_inv((unsigned long)addr, size);
 		break;

 	case DMA_BIDIRECTIONAL:
 		dma_cache_wback_inv((unsigned long)addr, size);
 		break;

 	default:
 		BUG();
 	}
 }

 /*
  * A single sg entry may refer to multiple physically contiguous
  * pages. But we still need to process highmem pages individually.
  * If highmem is not configured then the bulk of this loop gets
  * optimized out.
  */
 static inline void __dma_sync(struct page *page,
 	unsigned long offset, size_t size, enum dma_data_direction direction)
 {
 	size_t left = size;

 	do {
 		size_t len = left;

 		if (PageHighMem(page)) {
 			void *addr;

 			if (offset + len > PAGE_SIZE) {
 				if (offset >= PAGE_SIZE) {
 					page += offset >> PAGE_SHIFT;
 					offset &= ~PAGE_MASK;
 				}
 				len = PAGE_SIZE - offset;
 			}

 			addr = kmap_atomic(page);
 			__dma_sync_virtual(addr + offset, len, direction);
 			kunmap_atomic(addr);
 		} else
 			__dma_sync_virtual(page_address(page) + offset,
 					   size, direction);
 		offset = 0;
 		page++;
 		left -= len;
 	} while (left);
 }

 static void mips_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
 	size_t size, enum dma_data_direction direction, unsigned long attrs)
 {
 	if (cpu_needs_post_dma_flush(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 		__dma_sync(dma_addr_to_page(dev, dma_addr),
 			   dma_addr & ~PAGE_MASK, size, direction);
 	plat_post_dma_flush(dev);
 	plat_unmap_dma_mem(dev, dma_addr, size, direction);
 }

 static int mips_dma_map_sg(struct device *dev, struct scatterlist *sglist,
 	int nents, enum dma_data_direction direction, unsigned long attrs)
 {
 	int i;
 	struct scatterlist *sg;

 	for_each_sg(sglist, sg, nents, i) {
 		if (!plat_device_is_coherent(dev) &&
 		    !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 			__dma_sync(sg_page(sg), sg->offset, sg->length,
 				   direction);
 #ifdef CONFIG_NEED_SG_DMA_LENGTH
 		sg->dma_length = sg->length;
 #endif
 		sg->dma_address = plat_map_dma_mem_page(dev, sg_page(sg)) +
 				  sg->offset;
 	}

 	return nents;
 }

 static dma_addr_t mips_dma_map_page(struct device *dev, struct page *page,
 	unsigned long offset, size_t size, enum dma_data_direction direction,
 	unsigned long attrs)
 {
 	if (!plat_device_is_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 		__dma_sync(page, offset, size, direction);

 	return plat_map_dma_mem_page(dev, page) + offset;
 }

 static void mips_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
 	int nhwentries, enum dma_data_direction direction,
 	unsigned long attrs)
 {
 	int i;
 	struct scatterlist *sg;

 	for_each_sg(sglist, sg, nhwentries, i) {
 		if (!plat_device_is_coherent(dev) &&
 		    !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
 		    direction != DMA_TO_DEVICE)
 			__dma_sync(sg_page(sg), sg->offset, sg->length,
 				   direction);
 		plat_unmap_dma_mem(dev, sg->dma_address, sg->length, direction);
 	}
 }

 static void mips_dma_sync_single_for_cpu(struct device *dev,
 	dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
 {
 	if (cpu_needs_post_dma_flush(dev))
 		__dma_sync(dma_addr_to_page(dev, dma_handle),
 			   dma_handle & ~PAGE_MASK, size, direction);
 	plat_post_dma_flush(dev);
 }

 static void mips_dma_sync_single_for_device(struct device *dev,
 	dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
 {
 	if (!plat_device_is_coherent(dev))
 		__dma_sync(dma_addr_to_page(dev, dma_handle),
 			   dma_handle & ~PAGE_MASK, size, direction);
 }

 static void mips_dma_sync_sg_for_cpu(struct device *dev,
 	struct scatterlist *sglist, int nelems,
 	enum dma_data_direction direction)
 {
 	int i;
 	struct scatterlist *sg;

 	if (cpu_needs_post_dma_flush(dev)) {
 		for_each_sg(sglist, sg, nelems, i) {
 			__dma_sync(sg_page(sg), sg->offset, sg->length,
 				   direction);
 		}
 	}
 	plat_post_dma_flush(dev);
 }

 static void mips_dma_sync_sg_for_device(struct device *dev,
 	struct scatterlist *sglist, int nelems,
 	enum dma_data_direction direction)
 {
 	int i;
 	struct scatterlist *sg;

 	if (!plat_device_is_coherent(dev)) {
 		for_each_sg(sglist, sg, nelems, i) {
 			__dma_sync(sg_page(sg), sg->offset, sg->length,
 				   direction);
 		}
 	}
 }

 int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 {
 	return 0;
 }

 int mips_dma_supported(struct device *dev, u64 mask)
 {
 	return plat_dma_supported(dev, mask);
 }

 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 			 enum dma_data_direction direction)
 {
 	BUG_ON(direction == DMA_NONE);

 	if (!plat_device_is_coherent(dev))
 		__dma_sync_virtual(vaddr, size, direction);
 }

 EXPORT_SYMBOL(dma_cache_sync);

 static const struct dma_map_ops mips_default_dma_map_ops = {
 	.alloc = mips_dma_alloc_coherent,
 	.free = mips_dma_free_coherent,
 	.mmap = mips_dma_mmap,
 	.map_page = mips_dma_map_page,
 	.unmap_page = mips_dma_unmap_page,
 	.map_sg = mips_dma_map_sg,
 	.unmap_sg = mips_dma_unmap_sg,
 	.sync_single_for_cpu = mips_dma_sync_single_for_cpu,
 	.sync_single_for_device = mips_dma_sync_single_for_device,
 	.sync_sg_for_cpu = mips_dma_sync_sg_for_cpu,
 	.sync_sg_for_device = mips_dma_sync_sg_for_device,
 	.mapping_error = mips_dma_mapping_error,
 	.dma_supported = mips_dma_supported
 };

 const struct dma_map_ops *mips_dma_map_ops = &mips_default_dma_map_ops;
 EXPORT_SYMBOL(mips_dma_map_ops);

 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)

 static int __init mips_dma_init(void)
 {
 	dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);

 	return 0;
 }
 fs_initcall(mips_dma_init);
	/*
	* This file is subject to the terms and conditions of the GNU General Public
	* License. See the file "COPYING" in the main directory of this archive
	* for more details.
	*
	* Copyright (C) 2000 Ani Joshi <[email protected]>
	* Copyright (C) 2000, 2001, 06 Ralf Baechle <[email protected]>
	* swiped from i386, and cloned for MIPS by Geert, polished by Ralf.
	*/

	#include <linux/types.h>
	#include <linux/dma-mapping.h>
	#include <linux/mm.h>
	#include <linux/export.h>
	#include <linux/scatterlist.h>
	#include <linux/string.h>
	#include <linux/gfp.h>
	#include <linux/highmem.h>
	#include <linux/dma-contiguous.h>

	#include <asm/cache.h>
	#include <asm/cpu-type.h>
	#include <asm/io.h>

	#include <dma-coherence.h>

	#if defined(CONFIG_DMA_MAYBE_COHERENT) && !defined(CONFIG_DMA_PERDEV_COHERENT)
	/* User defined DMA coherency from command line. */
	enum coherent_io_user_state coherentio = IO_COHERENCE_DEFAULT;
	EXPORT_SYMBOL_GPL(coherentio);
	int hw_coherentio = 0; /* Actual hardware supported DMA coherency setting. */

	static int __init setcoherentio(char *str)
	{
	coherentio = IO_COHERENCE_ENABLED;
	pr_info("Hardware DMA cache coherency (command line)\n");
	return 0;
	}
	early_param("coherentio", setcoherentio);

	static int __init setnocoherentio(char *str)
	{
	coherentio = IO_COHERENCE_DISABLED;
	pr_info("Software DMA cache coherency (command line)\n");
	return 0;
	}
	early_param("nocoherentio", setnocoherentio);
	#endif

	static inline struct page dma_addr_to_page(struct device dev,
	dma_addr_t dma_addr)
	{
	return pfn_to_page(
	plat_dma_addr_to_phys(dev, dma_addr) >> PAGE_SHIFT);
	}

	/*
	* The affected CPUs below in 'cpu_needs_post_dma_flush()' can
	* speculatively fill random cachelines with stale data at any time,
	* requiring an extra flush post-DMA.
	*
	* Warning on the terminology - Linux calls an uncached area coherent;
	* MIPS terminology calls memory areas with hardware maintained coherency
	* coherent.
	*
	* Note that the R14000 and R16000 should also be checked for in this
	* condition. However this function is only called on non-I/O-coherent
	* systems and only the R10000 and R12000 are used in such systems, the
	* SGI IP28 Indigo² rsp. SGI IP32 aka O2.
	*/
	static inline bool cpu_needs_post_dma_flush(struct device *dev)
	{
	if (plat_device_is_coherent(dev))
	return false;

	switch (boot_cpu_type()) {
	case CPU_R10000:
	case CPU_R12000:
	case CPU_BMIPS5000:
	return true;

	default:
	/*
	* Presence of MAARs suggests that the CPU supports
	* speculatively prefetching data, and therefore requires
	* the post-DMA flush/invalidate.
	*/
	return cpu_has_maar;
	}
	}

	static gfp_t massage_gfp_flags(const struct device *dev, gfp_t gfp)
	{
	gfp_t dma_flag;

	/* ignore region specifiers */
	gfp &= ~(__GFP_DMA \| __GFP_DMA32 \| __GFP_HIGHMEM);

	#ifdef CONFIG_ISA
	if (dev == NULL)
	dma_flag = __GFP_DMA;
	else
	#endif
	#if defined(CONFIG_ZONE_DMA32) && defined(CONFIG_ZONE_DMA)
	if (dev == NULL \|\| dev->coherent_dma_mask < DMA_BIT_MASK(32))
	dma_flag = __GFP_DMA;
	else if (dev->coherent_dma_mask < DMA_BIT_MASK(64))
	dma_flag = __GFP_DMA32;
	else
	#endif
	#if defined(CONFIG_ZONE_DMA32) && !defined(CONFIG_ZONE_DMA)
	if (dev == NULL \|\| dev->coherent_dma_mask < DMA_BIT_MASK(64))
	dma_flag = __GFP_DMA32;
	else
	#endif
	#if defined(CONFIG_ZONE_DMA) && !defined(CONFIG_ZONE_DMA32)
	if (dev == NULL \|\|
	dev->coherent_dma_mask < DMA_BIT_MASK(sizeof(phys_addr_t) * 8))
	dma_flag = __GFP_DMA;
	else
	#endif
	dma_flag = 0;

	/* Don't invoke OOM killer */
	gfp \|= __GFP_NORETRY;

	return gfp \| dma_flag;
	}

	static void mips_dma_alloc_noncoherent(struct device dev, size_t size,
	dma_addr_t * dma_handle, gfp_t gfp)
	{
	void *ret;

	gfp = massage_gfp_flags(dev, gfp);

	ret = (void *) __get_free_pages(gfp, get_order(size));

	if (ret != NULL) {
	memset(ret, 0, size);
	*dma_handle = plat_map_dma_mem(dev, ret, size);
	}

	return ret;
	}

	static void mips_dma_alloc_coherent(struct device dev, size_t size,
	dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
	{
	void *ret;
	struct page *page = NULL;
	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;

	/*
	* XXX: seems like the coherent and non-coherent implementations could
	* be consolidated.
	*/
	if (attrs & DMA_ATTR_NON_CONSISTENT)
	return mips_dma_alloc_noncoherent(dev, size, dma_handle, gfp);

	gfp = massage_gfp_flags(dev, gfp);

	if (IS_ENABLED(CONFIG_DMA_CMA) && gfpflags_allow_blocking(gfp))
	page = dma_alloc_from_contiguous(dev, count, get_order(size),
	gfp);
	if (!page)
	page = alloc_pages(gfp, get_order(size));

	if (!page)
	return NULL;

	ret = page_address(page);
	memset(ret, 0, size);
	*dma_handle = plat_map_dma_mem(dev, ret, size);
	if (!plat_device_is_coherent(dev)) {
	dma_cache_wback_inv((unsigned long) ret, size);
	ret = UNCAC_ADDR(ret);
	}

	return ret;
	}


	static void mips_dma_free_noncoherent(struct device *dev, size_t size,
	void *vaddr, dma_addr_t dma_handle)
	{
	plat_unmap_dma_mem(dev, dma_handle, size, DMA_BIDIRECTIONAL);
	free_pages((unsigned long) vaddr, get_order(size));
	}

	static void mips_dma_free_coherent(struct device dev, size_t size, void vaddr,
	dma_addr_t dma_handle, unsigned long attrs)
	{
	unsigned long addr = (unsigned long) vaddr;
	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
	struct page *page = NULL;

	if (attrs & DMA_ATTR_NON_CONSISTENT) {
	mips_dma_free_noncoherent(dev, size, vaddr, dma_handle);
	return;
	}

	plat_unmap_dma_mem(dev, dma_handle, size, DMA_BIDIRECTIONAL);

	if (!plat_device_is_coherent(dev))
	addr = CAC_ADDR(addr);

	page = virt_to_page((void *) addr);

	if (!dma_release_from_contiguous(dev, page, count))
	__free_pages(page, get_order(size));
	}

	static int mips_dma_mmap(struct device dev, struct vm_area_struct vma,
	void *cpu_addr, dma_addr_t dma_addr, size_t size,
	unsigned long attrs)
	{
	unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
	unsigned long addr = (unsigned long)cpu_addr;
	unsigned long off = vma->vm_pgoff;
	unsigned long pfn;
	int ret = -ENXIO;

	if (!plat_device_is_coherent(dev))
	addr = CAC_ADDR(addr);

	pfn = page_to_pfn(virt_to_page((void *)addr));

	if (attrs & DMA_ATTR_WRITE_COMBINE)
	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
	else
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
	return ret;

	if (off < count && user_count <= (count - off)) {
	ret = remap_pfn_range(vma, vma->vm_start,
	pfn + off,
	user_count << PAGE_SHIFT,
	vma->vm_page_prot);
	}

	return ret;
	}

	static inline void __dma_sync_virtual(void *addr, size_t size,
	enum dma_data_direction direction)
	{
	switch (direction) {
	case DMA_TO_DEVICE:
	dma_cache_wback((unsigned long)addr, size);
	break;

	case DMA_FROM_DEVICE:
	dma_cache_inv((unsigned long)addr, size);
	break;

	case DMA_BIDIRECTIONAL:
	dma_cache_wback_inv((unsigned long)addr, size);
	break;

	default:
	BUG();
	}
	}

	/*
	* A single sg entry may refer to multiple physically contiguous
	* pages. But we still need to process highmem pages individually.
	* If highmem is not configured then the bulk of this loop gets
	* optimized out.
	*/
	static inline void __dma_sync(struct page *page,
	unsigned long offset, size_t size, enum dma_data_direction direction)
	{
	size_t left = size;

	do {
	size_t len = left;

	if (PageHighMem(page)) {
	void *addr;

	if (offset + len > PAGE_SIZE) {
	if (offset >= PAGE_SIZE) {
	page += offset >> PAGE_SHIFT;
	offset &= ~PAGE_MASK;
	}
	len = PAGE_SIZE - offset;
	}

	addr = kmap_atomic(page);
	__dma_sync_virtual(addr + offset, len, direction);
	kunmap_atomic(addr);
	} else
	__dma_sync_virtual(page_address(page) + offset,
	size, direction);
	offset = 0;
	page++;
	left -= len;
	} while (left);
	}

	static void mips_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
	size_t size, enum dma_data_direction direction, unsigned long attrs)
	{
	if (cpu_needs_post_dma_flush(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
	__dma_sync(dma_addr_to_page(dev, dma_addr),
	dma_addr & ~PAGE_MASK, size, direction);
	plat_post_dma_flush(dev);
	plat_unmap_dma_mem(dev, dma_addr, size, direction);
	}

	static int mips_dma_map_sg(struct device dev, struct scatterlist sglist,
	int nents, enum dma_data_direction direction, unsigned long attrs)
	{
	int i;
	struct scatterlist *sg;

	for_each_sg(sglist, sg, nents, i) {
	if (!plat_device_is_coherent(dev) &&
	!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
	__dma_sync(sg_page(sg), sg->offset, sg->length,
	direction);
	#ifdef CONFIG_NEED_SG_DMA_LENGTH
	sg->dma_length = sg->length;
	#endif
	sg->dma_address = plat_map_dma_mem_page(dev, sg_page(sg)) +
	sg->offset;
	}

	return nents;
	}

	static dma_addr_t mips_dma_map_page(struct device dev, struct page page,
	unsigned long offset, size_t size, enum dma_data_direction direction,
	unsigned long attrs)
	{
	if (!plat_device_is_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
	__dma_sync(page, offset, size, direction);

	return plat_map_dma_mem_page(dev, page) + offset;
	}

	static void mips_dma_unmap_sg(struct device dev, struct scatterlist sglist,
	int nhwentries, enum dma_data_direction direction,
	unsigned long attrs)
	{
	int i;
	struct scatterlist *sg;

	for_each_sg(sglist, sg, nhwentries, i) {
	if (!plat_device_is_coherent(dev) &&
	!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
	direction != DMA_TO_DEVICE)
	__dma_sync(sg_page(sg), sg->offset, sg->length,
	direction);
	plat_unmap_dma_mem(dev, sg->dma_address, sg->length, direction);
	}
	}

	static void mips_dma_sync_single_for_cpu(struct device *dev,
	dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
	{
	if (cpu_needs_post_dma_flush(dev))
	__dma_sync(dma_addr_to_page(dev, dma_handle),
	dma_handle & ~PAGE_MASK, size, direction);
	plat_post_dma_flush(dev);
	}

	static void mips_dma_sync_single_for_device(struct device *dev,
	dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
	{
	if (!plat_device_is_coherent(dev))
	__dma_sync(dma_addr_to_page(dev, dma_handle),
	dma_handle & ~PAGE_MASK, size, direction);
	}

	static void mips_dma_sync_sg_for_cpu(struct device *dev,
	struct scatterlist *sglist, int nelems,
	enum dma_data_direction direction)
	{
	int i;
	struct scatterlist *sg;

	if (cpu_needs_post_dma_flush(dev)) {
	for_each_sg(sglist, sg, nelems, i) {
	__dma_sync(sg_page(sg), sg->offset, sg->length,
	direction);
	}
	}
	plat_post_dma_flush(dev);
	}

	static void mips_dma_sync_sg_for_device(struct device *dev,
	struct scatterlist *sglist, int nelems,
	enum dma_data_direction direction)
	{
	int i;
	struct scatterlist *sg;

	if (!plat_device_is_coherent(dev)) {
	for_each_sg(sglist, sg, nelems, i) {
	__dma_sync(sg_page(sg), sg->offset, sg->length,
	direction);
	}
	}
	}

	int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
	{
	return 0;
	}

	int mips_dma_supported(struct device *dev, u64 mask)
	{
	return plat_dma_supported(dev, mask);
	}

	void dma_cache_sync(struct device dev, void vaddr, size_t size,
	enum dma_data_direction direction)
	{
	BUG_ON(direction == DMA_NONE);

	if (!plat_device_is_coherent(dev))
	__dma_sync_virtual(vaddr, size, direction);
	}

	EXPORT_SYMBOL(dma_cache_sync);

	static const struct dma_map_ops mips_default_dma_map_ops = {
	.alloc = mips_dma_alloc_coherent,
	.free = mips_dma_free_coherent,
	.mmap = mips_dma_mmap,
	.map_page = mips_dma_map_page,
	.unmap_page = mips_dma_unmap_page,
	.map_sg = mips_dma_map_sg,
	.unmap_sg = mips_dma_unmap_sg,
	.sync_single_for_cpu = mips_dma_sync_single_for_cpu,
	.sync_single_for_device = mips_dma_sync_single_for_device,
	.sync_sg_for_cpu = mips_dma_sync_sg_for_cpu,
	.sync_sg_for_device = mips_dma_sync_sg_for_device,
	.mapping_error = mips_dma_mapping_error,
	.dma_supported = mips_dma_supported
	};

	const struct dma_map_ops *mips_dma_map_ops = &mips_default_dma_map_ops;
	EXPORT_SYMBOL(mips_dma_map_ops);

	#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)

	static int __init mips_dma_init(void)
	{
	dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);

	return 0;
	}
	fs_initcall(mips_dma_init);