1. 根目录:
2. arch
3. microblaze
4. include
5. asm
6. dma-mapping.h

/*
 * Implements the generic device dma API for microblaze and the pci
 *
 * Copyright (C) 2009-2010 Michal Simek <monstr@monstr.eu>
 * Copyright (C) 2009-2010 PetaLogix
 *
 * 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.
 *
 * This file is base on powerpc and x86 dma-mapping.h versions
 * Copyright (C) 2004 IBM
 */

#ifndef _ASM_MICROBLAZE_DMA_MAPPING_H
#define _ASM_MICROBLAZE_DMA_MAPPING_H

/*
 * See Documentation/DMA-API-HOWTO.txt and
 * Documentation/DMA-API.txt for documentation.
 */

#include <linux/types.h>
#include <linux/cache.h>
#include <linux/mm.h>
#include <linux/scatterlist.h>
#include <linux/dma-debug.h>
#include <linux/dma-attrs.h>
#include <asm/io.h>
#include <asm-generic/dma-coherent.h>
#include <asm/cacheflush.h>

#define DMA_ERROR_CODE		(~(dma_addr_t)0x0)

#define __dma_alloc_coherent(dev, gfp, size, handle)	NULL
#define __dma_free_coherent(size, addr)		((void)0)

static inline unsigned long device_to_mask(struct device *dev)
{
	if (dev->dma_mask && *dev->dma_mask)
		return *dev->dma_mask;
	/* Assume devices without mask can take 32 bit addresses */
	return 0xfffffffful;
}

extern struct dma_map_ops *dma_ops;

/*
 * Available generic sets of operations
 */
extern struct dma_map_ops dma_direct_ops;

static inline struct dma_map_ops *get_dma_ops(struct device *dev)
{
	/* We don't handle the NULL dev case for ISA for now. We could
	 * do it via an out of line call but it is not needed for now. The
	 * only ISA DMA device we support is the floppy and we have a hack
	 * in the floppy driver directly to get a device for us.
	 */
	if (unlikely(!dev) || !dev->archdata.dma_ops)
		return NULL;

	return dev->archdata.dma_ops;
}

static inline void set_dma_ops(struct device *dev, struct dma_map_ops *ops)
{
	dev->archdata.dma_ops = ops;
}

static inline int dma_supported(struct device *dev, u64 mask)
{
	struct dma_map_ops *ops = get_dma_ops(dev);

	if (unlikely(!ops))
		return 0;
	if (!ops->dma_supported)
		return 1;
	return ops->dma_supported(dev, mask);
}

static inline int dma_set_mask(struct device *dev, u64 dma_mask)
{
	struct dma_map_ops *ops = get_dma_ops(dev);

	if (unlikely(ops == NULL))
		return -EIO;
	if (ops->set_dma_mask)
		return ops->set_dma_mask(dev, dma_mask);
	if (!dev->dma_mask || !dma_supported(dev, dma_mask))
		return -EIO;
	*dev->dma_mask = dma_mask;
	return 0;
}

#include <asm-generic/dma-mapping-common.h>

static inline void __dma_sync(unsigned long paddr,
			      size_t size, enum dma_data_direction direction)
{
	switch (direction) {
	case DMA_TO_DEVICE:
	case DMA_BIDIRECTIONAL:
		flush_dcache_range(paddr, paddr + size);
		break;
	case DMA_FROM_DEVICE:
		invalidate_dcache_range(paddr, paddr + size);
		break;
	default:
		BUG();
	}
}

static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
	struct dma_map_ops *ops = get_dma_ops(dev);

	debug_dma_mapping_error(dev, dma_addr);
	if (ops->mapping_error)
		return ops->mapping_error(dev, dma_addr);

	return (dma_addr == DMA_ERROR_CODE);
}

#define dma_alloc_noncoherent(d, s, h, f) dma_alloc_coherent(d, s, h, f)
#define dma_free_noncoherent(d, s, v, h) dma_free_coherent(d, s, v, h)

#define dma_alloc_coherent(d, s, h, f) dma_alloc_attrs(d, s, h, f, NULL)

static inline void *dma_alloc_attrs(struct device *dev, size_t size,
				    dma_addr_t *dma_handle, gfp_t flag,
				    struct dma_attrs *attrs)
{
	struct dma_map_ops *ops = get_dma_ops(dev);
	void *memory;

	BUG_ON(!ops);

	memory = ops->alloc(dev, size, dma_handle, flag, attrs);

	debug_dma_alloc_coherent(dev, size, *dma_handle, memory);
	return memory;
}

#define dma_free_coherent(d,s,c,h) dma_free_attrs(d, s, c, h, NULL)

static inline void dma_free_attrs(struct device *dev, size_t size,
				  void *cpu_addr, dma_addr_t dma_handle,
				  struct dma_attrs *attrs)
{
	struct dma_map_ops *ops = get_dma_ops(dev);

	BUG_ON(!ops);
	debug_dma_free_coherent(dev, size, cpu_addr, dma_handle);
	ops->free(dev, size, cpu_addr, dma_handle, attrs);
}

static inline void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
		enum dma_data_direction direction)
{
	BUG_ON(direction == DMA_NONE);
	__dma_sync(virt_to_phys(vaddr), size, (int)direction);
}

#endif	/* _ASM_MICROBLAZE_DMA_MAPPING_H */