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dma-mapping.h

#ifndef __ASM_AVR32_DMA_MAPPING_H
#define __ASM_AVR32_DMA_MAPPING_H

#include <linux/mm.h>
#include <linux/device.h>
#include <linux/scatterlist.h>
#include <asm/processor.h>
#include <asm/cacheflush.h>
#include <asm/io.h>

extern void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
      int direction);

/*
 * Return whether the given device DMA address mask can be supported
 * properly.  For example, if your device can only drive the low 24-bits
 * during bus mastering, then you would pass 0x00ffffff as the mask
 * to this function.
 */
static inline int dma_supported(struct device *dev, u64 mask)
{
      /* Fix when needed. I really don't know of any limitations */
      return 1;
}

static inline int dma_set_mask(struct device *dev, u64 dma_mask)
{
      if (!dev->dma_mask || !dma_supported(dev, dma_mask))
            return -EIO;

      *dev->dma_mask = dma_mask;
      return 0;
}

/*
 * dma_map_single can't fail as it is implemented now.
 */
static inline int dma_mapping_error(struct device *dev, dma_addr_t addr)
{
      return 0;
}

/**
 * dma_alloc_coherent - allocate consistent memory for DMA
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @size: required memory size
 * @handle: bus-specific DMA address
 *
 * Allocate some uncached, unbuffered memory for a device for
 * performing DMA.  This function allocates pages, and will
 * return the CPU-viewed address, and sets @handle to be the
 * device-viewed address.
 */
extern void *dma_alloc_coherent(struct device *dev, size_t size,
                        dma_addr_t *handle, gfp_t gfp);

/**
 * dma_free_coherent - free memory allocated by dma_alloc_coherent
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @size: size of memory originally requested in dma_alloc_coherent
 * @cpu_addr: CPU-view address returned from dma_alloc_coherent
 * @handle: device-view address returned from dma_alloc_coherent
 *
 * Free (and unmap) a DMA buffer previously allocated by
 * dma_alloc_coherent().
 *
 * References to memory and mappings associated with cpu_addr/handle
 * during and after this call executing are illegal.
 */
extern void dma_free_coherent(struct device *dev, size_t size,
                        void *cpu_addr, dma_addr_t handle);

/**
 * dma_alloc_writecombine - allocate write-combining memory for DMA
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @size: required memory size
 * @handle: bus-specific DMA address
 *
 * Allocate some uncached, buffered memory for a device for
 * performing DMA.  This function allocates pages, and will
 * return the CPU-viewed address, and sets @handle to be the
 * device-viewed address.
 */
extern void *dma_alloc_writecombine(struct device *dev, size_t size,
                            dma_addr_t *handle, gfp_t gfp);

/**
 * dma_free_coherent - free memory allocated by dma_alloc_writecombine
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @size: size of memory originally requested in dma_alloc_writecombine
 * @cpu_addr: CPU-view address returned from dma_alloc_writecombine
 * @handle: device-view address returned from dma_alloc_writecombine
 *
 * Free (and unmap) a DMA buffer previously allocated by
 * dma_alloc_writecombine().
 *
 * References to memory and mappings associated with cpu_addr/handle
 * during and after this call executing are illegal.
 */
extern void dma_free_writecombine(struct device *dev, size_t size,
                          void *cpu_addr, dma_addr_t handle);

/**
 * dma_map_single - map a single buffer for streaming DMA
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @cpu_addr: CPU direct mapped address of buffer
 * @size: size of buffer to map
 * @dir: DMA transfer direction
 *
 * Ensure that any data held in the cache is appropriately discarded
 * or written back.
 *
 * The device owns this memory once this call has completed.  The CPU
 * can regain ownership by calling dma_unmap_single() or dma_sync_single().
 */
static inline dma_addr_t
dma_map_single(struct device *dev, void *cpu_addr, size_t size,
             enum dma_data_direction direction)
{
      dma_cache_sync(dev, cpu_addr, size, direction);
      return virt_to_bus(cpu_addr);
}

/**
 * dma_unmap_single - unmap a single buffer previously mapped
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @handle: DMA address of buffer
 * @size: size of buffer to map
 * @dir: DMA transfer direction
 *
 * Unmap a single streaming mode DMA translation.  The handle and size
 * must match what was provided in the previous dma_map_single() call.
 * All other usages are undefined.
 *
 * After this call, reads by the CPU to the buffer are guaranteed to see
 * whatever the device wrote there.
 */
static inline void
dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
             enum dma_data_direction direction)
{

}

/**
 * dma_map_page - map a portion of a page for streaming DMA
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @page: page that buffer resides in
 * @offset: offset into page for start of buffer
 * @size: size of buffer to map
 * @dir: DMA transfer direction
 *
 * Ensure that any data held in the cache is appropriately discarded
 * or written back.
 *
 * The device owns this memory once this call has completed.  The CPU
 * can regain ownership by calling dma_unmap_page() or dma_sync_single().
 */
static inline dma_addr_t
dma_map_page(struct device *dev, struct page *page,
           unsigned long offset, size_t size,
           enum dma_data_direction direction)
{
      return dma_map_single(dev, page_address(page) + offset,
                        size, direction);
}

/**
 * dma_unmap_page - unmap a buffer previously mapped through dma_map_page()
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @handle: DMA address of buffer
 * @size: size of buffer to map
 * @dir: DMA transfer direction
 *
 * Unmap a single streaming mode DMA translation.  The handle and size
 * must match what was provided in the previous dma_map_single() call.
 * All other usages are undefined.
 *
 * After this call, reads by the CPU to the buffer are guaranteed to see
 * whatever the device wrote there.
 */
static inline void
dma_unmap_page(struct device *dev, dma_addr_t dma_address, size_t size,
             enum dma_data_direction direction)
{
      dma_unmap_single(dev, dma_address, size, direction);
}

/**
 * dma_map_sg - map a set of SG buffers for streaming mode DMA
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @sg: list of buffers
 * @nents: number of buffers to map
 * @dir: DMA transfer direction
 *
 * Map a set of buffers described by scatterlist in streaming
 * mode for DMA.  This is the scatter-gather version of the
 * above pci_map_single interface.  Here the scatter gather list
 * elements are each tagged with the appropriate dma address
 * and length.  They are obtained via sg_dma_{address,length}(SG).
 *
 * NOTE: An implementation may be able to use a smaller number of
 *       DMA address/length pairs than there are SG table elements.
 *       (for example via virtual mapping capabilities)
 *       The routine returns the number of addr/length pairs actually
 *       used, at most nents.
 *
 * Device ownership issues as mentioned above for pci_map_single are
 * the same here.
 */
static inline int
dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
         enum dma_data_direction direction)
{
      int i;

      for (i = 0; i < nents; i++) {
            char *virt;

            sg[i].dma_address = page_to_bus(sg_page(&sg[i])) + sg[i].offset;
            virt = sg_virt(&sg[i]);
            dma_cache_sync(dev, virt, sg[i].length, direction);
      }

      return nents;
}

/**
 * dma_unmap_sg - unmap a set of SG buffers mapped by dma_map_sg
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @sg: list of buffers
 * @nents: number of buffers to map
 * @dir: DMA transfer direction
 *
 * Unmap a set of streaming mode DMA translations.
 * Again, CPU read rules concerning calls here are the same as for
 * pci_unmap_single() above.
 */
static inline void
dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nhwentries,
           enum dma_data_direction direction)
{

}

/**
 * dma_sync_single_for_cpu
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @handle: DMA address of buffer
 * @size: size of buffer to map
 * @dir: DMA transfer direction
 *
 * Make physical memory consistent for a single streaming mode DMA
 * translation after a transfer.
 *
 * If you perform a dma_map_single() but wish to interrogate the
 * buffer using the cpu, yet do not wish to teardown the DMA mapping,
 * you must call this function before doing so.  At the next point you
 * give the DMA address back to the card, you must first perform a
 * dma_sync_single_for_device, and then the device again owns the
 * buffer.
 */
static inline void
dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
                  size_t size, enum dma_data_direction direction)
{
      /*
       * No need to do anything since the CPU isn't supposed to
       * touch this memory after we flushed it at mapping- or
       * sync-for-device time.
       */
}

static inline void
dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle,
                     size_t size, enum dma_data_direction direction)
{
      dma_cache_sync(dev, bus_to_virt(dma_handle), size, direction);
}

static inline void
dma_sync_single_range_for_cpu(struct device *dev, dma_addr_t dma_handle,
                        unsigned long offset, size_t size,
                        enum dma_data_direction direction)
{
      /* just sync everything, that's all the pci API can do */
      dma_sync_single_for_cpu(dev, dma_handle, offset+size, direction);
}

static inline void
dma_sync_single_range_for_device(struct device *dev, dma_addr_t dma_handle,
                         unsigned long offset, size_t size,
                         enum dma_data_direction direction)
{
      /* just sync everything, that's all the pci API can do */
      dma_sync_single_for_device(dev, dma_handle, offset+size, direction);
}

/**
 * dma_sync_sg_for_cpu
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @sg: list of buffers
 * @nents: number of buffers to map
 * @dir: DMA transfer direction
 *
 * Make physical memory consistent for a set of streaming
 * mode DMA translations after a transfer.
 *
 * The same as dma_sync_single_for_* but for a scatter-gather list,
 * same rules and usage.
 */
static inline void
dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
                int nents, enum dma_data_direction direction)
{
      /*
       * No need to do anything since the CPU isn't supposed to
       * touch this memory after we flushed it at mapping- or
       * sync-for-device time.
       */
}

static inline void
dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
                   int nents, enum dma_data_direction direction)
{
      int i;

      for (i = 0; i < nents; i++) {
            dma_cache_sync(dev, sg_virt(&sg[i]), sg[i].length, direction);
      }
}

/* Now for the API extensions over the pci_ one */

#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)

#endif /* __ASM_AVR32_DMA_MAPPING_H */

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