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/cacheflush.h>
  13 #include <asm/addrspace.h>
  14 #include <asm/io.h>
  15
  16 void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *handle)
  17 {
  18         struct page *page, *end, *free;
  19         void *ret;
  20         int order;
  21
  22         size = PAGE_ALIGN(size);
  23         order = get_order(size);
  24
  25         page = alloc_pages(gfp, order);
  26         if (!page)
  27                 return NULL;
  28         split_page(page, order);
  29
  30         ret = page_address(page);
  31         memset(ret, 0, size);
  32         *handle = virt_to_phys(ret);
  33
  34         /*
  35          * We must flush the cache before we pass it on to the device
  36          */
  37         dma_cache_wback_inv(ret, size);
  38
  39         page = virt_to_page(ret);
  40         free = page + (size >> PAGE_SHIFT);
  41         end  = page + (1 << order);
  42
  43         while (++page < end) {
  44                 /* Free any unused pages */
  45                 if (page >= free) {
  46                         __free_page(page);
  47                 }
  48         }
  49
  50         return P2SEGADDR(ret);
  51 }
  52
  53 void consistent_free(void *vaddr, size_t size)
  54 {
  55         unsigned long addr = P1SEGADDR((unsigned long)vaddr);
  56         struct page *page=virt_to_page(addr);
  57         int num_pages=(size+PAGE_SIZE-1) >> PAGE_SHIFT;
  58         int i;
  59
  60         for(i=0;i<num_pages;i++) {
  61                 __free_page((page+i));
  62         }
  63 }
  64
  65 void consistent_sync(void *vaddr, size_t size, int direction)
  66 {
  67         void * p1addr = (void*) P1SEGADDR((unsigned long)vaddr);
  68
  69         switch (direction) {
  70         case DMA_FROM_DEVICE:           /* invalidate only */
  71                 dma_cache_inv(p1addr, size);
  72                 break;
  73         case DMA_TO_DEVICE:             /* writeback only */
  74                 dma_cache_wback(p1addr, size);
  75                 break;
  76         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
  77                 dma_cache_wback_inv(p1addr, size);
  78                 break;
  79         default:
  80                 BUG();
  81         }
  82 }
  83
  84 EXPORT_SYMBOL(consistent_alloc);
  85 EXPORT_SYMBOL(consistent_free);
  86 EXPORT_SYMBOL(consistent_sync);
  87