arch/sh/mm/consistent.c

   1 /*
   2  * arch/sh/mm/consistent.c
   3  *
   4  * Copyright (C) 2004  Paul Mundt
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License.  See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  */
  10 #include <linux/mm.h>
  11 #include <linux/dma-mapping.h>
  12 #include <asm/io.h>
  13
  14 void *consistent_alloc(int gfp, size_t size, dma_addr_t *handle)
  15 {
  16         struct page *page, *end, *free;
  17         void *ret;
  18         int order;
  19
  20         size = PAGE_ALIGN(size);
  21         order = get_order(size);
  22
  23         page = alloc_pages(gfp, order);
  24         if (!page)
  25                 return NULL;
  26
  27         ret = page_address(page);
  28         *handle = virt_to_phys(ret);
  29
  30         /*
  31          * We must flush the cache before we pass it on to the device
  32          */
  33         dma_cache_wback_inv(ret, size);
  34
  35         page = virt_to_page(ret);
  36         free = page + (size >> PAGE_SHIFT);
  37         end  = page + (1 << order);
  38
  39         while (++page < end) {
  40                 set_page_count(page, 1);
  41
  42                 /* Free any unused pages */
  43                 if (page >= free) {
  44                         __free_page(page);
  45                 }
  46         }
  47
  48         return P2SEGADDR(ret);
  49 }
  50
  51 void consistent_free(void *vaddr, size_t size)
  52 {
  53         unsigned long addr = P1SEGADDR((unsigned long)vaddr);
  54         struct page *page=virt_to_page(addr);
  55         int num_pages=(size+PAGE_SIZE-1) >> PAGE_SHIFT;
  56         int i;
  57
  58         for(i=0;i<num_pages;i++) {
  59                 __free_page((page+i));
  60         }
  61 }
  62
  63 void consistent_sync(void *vaddr, size_t size, int direction)
  64 {
  65         void * p1addr = (void*) P1SEGADDR((unsigned long)vaddr);
  66
  67         switch (direction) {
  68         case DMA_FROM_DEVICE:           /* invalidate only */
  69                 dma_cache_inv(p1addr, size);
  70                 break;
  71         case DMA_TO_DEVICE:             /* writeback only */
  72                 dma_cache_wback(p1addr, size);
  73                 break;
  74         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
  75                 dma_cache_wback_inv(p1addr, size);
  76                 break;
  77         default:
  78                 BUG();
  79         }
  80 }
  81
  82 EXPORT_SYMBOL(consistent_alloc);
  83 EXPORT_SYMBOL(consistent_free);
  84 EXPORT_SYMBOL(consistent_sync);
  85