Logo Search packages:      
Sourcecode: linux version File versions  Download package

pci-dma.c

/*
 * arch/xtensa/kernel/pci-dma.c
 *
 * DMA coherent memory allocation.
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 *
 * Copyright (C) 2002 - 2005 Tensilica Inc.
 *
 * Based on version for i386.
 *
 * Chris Zankel <chris@zankel.net>
 * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
 */

#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <asm/io.h>
#include <asm/cacheflush.h>

/*
 * Note: We assume that the full memory space is always mapped to 'kseg'
 *     Otherwise we have to use page attributes (not implemented).
 */

void *
dma_alloc_coherent(struct device *dev,size_t size,dma_addr_t *handle,gfp_t flag)
{
      unsigned long ret;
      unsigned long uncached = 0;

      /* ignore region speicifiers */

      flag &= ~(__GFP_DMA | __GFP_HIGHMEM);

      if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
            flag |= GFP_DMA;
      ret = (unsigned long)__get_free_pages(flag, get_order(size));

      if (ret == 0)
            return NULL;

      /* We currently don't support coherent memory outside KSEG */

      if (ret < XCHAL_KSEG_CACHED_VADDR
          || ret >= XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE)
            BUG();


      if (ret != 0) {
            memset((void*) ret, 0, size);
            uncached = ret+XCHAL_KSEG_BYPASS_VADDR-XCHAL_KSEG_CACHED_VADDR;
            *handle = virt_to_bus((void*)ret);
            __flush_invalidate_dcache_range(ret, size);
      }

      return (void*)uncached;
}

void dma_free_coherent(struct device *hwdev, size_t size,
                   void *vaddr, dma_addr_t dma_handle)
{
      long addr=(long)vaddr+XCHAL_KSEG_CACHED_VADDR-XCHAL_KSEG_BYPASS_VADDR;

      if (addr < 0 || addr >= XCHAL_KSEG_SIZE)
            BUG();

      free_pages(addr, get_order(size));
}


void consistent_sync(void *vaddr, size_t size, int direction)
{
      switch (direction) {
      case PCI_DMA_NONE:
            BUG();
      case PCI_DMA_FROMDEVICE:        /* invalidate only */
            __invalidate_dcache_range((unsigned long)vaddr,
                                  (unsigned long)size);
            break;

      case PCI_DMA_TODEVICE:          /* writeback only */
      case PCI_DMA_BIDIRECTIONAL:     /* writeback and invalidate */
            __flush_invalidate_dcache_range((unsigned long)vaddr,
                                    (unsigned long)size);
            break;
      }
}

Generated by  Doxygen 1.6.0   Back to index