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consistent.c

/*
 * arch/sh/mm/consistent.c
 *
 * Copyright (C) 2004  Paul Mundt
 *
 * 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.
 */
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <asm/cacheflush.h>
#include <asm/addrspace.h>
#include <asm/io.h>

void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *handle)
{
      struct page *page, *end, *free;
      void *ret;
      int order;

      size = PAGE_ALIGN(size);
      order = get_order(size);

      page = alloc_pages(gfp, order);
      if (!page)
            return NULL;
      split_page(page, order);

      ret = page_address(page);
      memset(ret, 0, size);
      *handle = virt_to_phys(ret);

      /*
       * We must flush the cache before we pass it on to the device
       */
      __flush_purge_region(ret, size);

      page = virt_to_page(ret);
      free = page + (size >> PAGE_SHIFT);
      end  = page + (1 << order);

      while (++page < end) {
            /* Free any unused pages */
            if (page >= free) {
                  __free_page(page);
            }
      }

      return P2SEGADDR(ret);
}

void consistent_free(void *vaddr, size_t size)
{
      unsigned long addr = P1SEGADDR((unsigned long)vaddr);
      struct page *page=virt_to_page(addr);
      int num_pages=(size+PAGE_SIZE-1) >> PAGE_SHIFT;
      int i;

      for(i=0;i<num_pages;i++) {
            __free_page((page+i));
      }
}

void consistent_sync(void *vaddr, size_t size, int direction)
{
      void * p1addr = (void*) P1SEGADDR((unsigned long)vaddr);

      switch (direction) {
      case DMA_FROM_DEVICE:         /* invalidate only */
            __flush_invalidate_region(p1addr, size);
            break;
      case DMA_TO_DEVICE:           /* writeback only */
            __flush_wback_region(p1addr, size);
            break;
      case DMA_BIDIRECTIONAL:       /* writeback and invalidate */
            __flush_purge_region(p1addr, size);
            break;
      default:
            BUG();
      }
}

EXPORT_SYMBOL(consistent_alloc);
EXPORT_SYMBOL(consistent_free);
EXPORT_SYMBOL(consistent_sync);


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