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(gfp_t 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         split_page(page, order);
  27
  28         ret = page_address(page);
  29         *handle = virt_to_phys(ret);
  30
  31         /*
  32          * We must flush the cache before we pass it on to the device
  33          */
  34         dma_cache_wback_inv(ret, size);
  35
  36         page = virt_to_page(ret);
  37         free = page + (size >> PAGE_SHIFT);
  38         end  = page + (1 << order);
  39
  40         while (++page < end) {
  41                 /* Free any unused pages */
  42                 if (page >= free) {
  43                         __free_page(page);
  44                 }
  45         }
  46
  47         return P2SEGADDR(ret);
  48 }
  49
  50 void consistent_free(void *vaddr, size_t size)
  51 {
  52         unsigned long addr = P1SEGADDR((unsigned long)vaddr);
  53         struct page *page=virt_to_page(addr);
  54         int num_pages=(size+PAGE_SIZE-1) >> PAGE_SHIFT;
  55         int i;
  56
  57         for(i=0;i<num_pages;i++) {
  58                 __free_page((page+i));
  59         }
  60 }
  61
  62 void consistent_sync(void *vaddr, size_t size, int direction)
  63 {
  64         void * p1addr = (void*) P1SEGADDR((unsigned long)vaddr);
  65
  66         switch (direction) {
  67         case DMA_FROM_DEVICE:           /* invalidate only */
  68                 dma_cache_inv(p1addr, size);
  69                 break;
  70         case DMA_TO_DEVICE:             /* writeback only */
  71                 dma_cache_wback(p1addr, size);
  72                 break;
  73         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
  74                 dma_cache_wback_inv(p1addr, size);
  75                 break;
  76         default:
  77                 BUG();
  78         }
  79 }
  80
  81 EXPORT_SYMBOL(consistent_alloc);
  82 EXPORT_SYMBOL(consistent_free);
  83 EXPORT_SYMBOL(consistent_sync);
  84