release/src-rt-6.x.4708/linux/linux-2.6.36/arch/avr32/mm/dma-coherent.c

   1 /*
   2  *  Copyright (C) 2004-2006 Atmel Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/dma-mapping.h>
  10 #include <linux/gfp.h>
  11
  12 #include <asm/addrspace.h>
  13 #include <asm/cacheflush.h>
  14
  15 void dma_cache_sync(struct device *dev, void *vaddr, size_t size, int direction)
  16 {
  17         /*
  18          * No need to sync an uncached area
  19          */
  20         if (PXSEG(vaddr) == P2SEG)
  21                 return;
  22
  23         switch (direction) {
  24         case DMA_FROM_DEVICE:           /* invalidate only */
  25                 invalidate_dcache_region(vaddr, size);
  26                 break;
  27         case DMA_TO_DEVICE:             /* writeback only */
  28                 clean_dcache_region(vaddr, size);
  29                 break;
  30         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
  31                 flush_dcache_region(vaddr, size);
  32                 break;
  33         default:
  34                 BUG();
  35         }
  36 }
  37 EXPORT_SYMBOL(dma_cache_sync);
  38
  39 static struct page *__dma_alloc(struct device *dev, size_t size,
  40                                 dma_addr_t *handle, gfp_t gfp)
  41 {
  42         struct page *page, *free, *end;
  43         int order;
  44
  45         gfp &= ~(__GFP_COMP);
  46
  47         size = PAGE_ALIGN(size);
  48         order = get_order(size);
  49
  50         page = alloc_pages(gfp, order);
  51         if (!page)
  52                 return NULL;
  53         split_page(page, order);
  54
  55         /*
  56          * When accessing physical memory with valid cache data, we
  57          * get a cache hit even if the virtual memory region is marked
  58          * as uncached.
  59          *
  60          * Since the memory is newly allocated, there is no point in
  61          * doing a writeback. If the previous owner cares, he should
  62          * have flushed the cache before releasing the memory.
  63          */
  64         invalidate_dcache_region(phys_to_virt(page_to_phys(page)), size);
  65
  66         *handle = page_to_bus(page);
  67         free = page + (size >> PAGE_SHIFT);
  68         end = page + (1 << order);
  69
  70         /*
  71          * Free any unused pages
  72          */
  73         while (free < end) {
  74                 __free_page(free);
  75                 free++;
  76         }
  77
  78         return page;
  79 }
  80
  81 static void __dma_free(struct device *dev, size_t size,
  82                        struct page *page, dma_addr_t handle)
  83 {
  84         struct page *end = page + (PAGE_ALIGN(size) >> PAGE_SHIFT);
  85
  86         while (page < end)
  87                 __free_page(page++);
  88 }
  89
  90 void *dma_alloc_coherent(struct device *dev, size_t size,
  91                          dma_addr_t *handle, gfp_t gfp)
  92 {
  93         struct page *page;
  94         void *ret = NULL;
  95
  96         page = __dma_alloc(dev, size, handle, gfp);
  97         if (page)
  98                 ret = phys_to_uncached(page_to_phys(page));
  99
 100         return ret;
 101 }
 102 EXPORT_SYMBOL(dma_alloc_coherent);
 103
 104 void dma_free_coherent(struct device *dev, size_t size,
 105                        void *cpu_addr, dma_addr_t handle)
 106 {
 107         void *addr = phys_to_cached(uncached_to_phys(cpu_addr));
 108         struct page *page;
 109
 110         pr_debug("dma_free_coherent addr %p (phys %08lx) size %u\n",
 111                  cpu_addr, (unsigned long)handle, (unsigned)size);
 112         BUG_ON(!virt_addr_valid(addr));
 113         page = virt_to_page(addr);
 114         __dma_free(dev, size, page, handle);
 115 }
 116 EXPORT_SYMBOL(dma_free_coherent);
 117
 118 void *dma_alloc_writecombine(struct device *dev, size_t size,
 119                              dma_addr_t *handle, gfp_t gfp)
 120 {
 121         struct page *page;
 122         dma_addr_t phys;
 123
 124         page = __dma_alloc(dev, size, handle, gfp);
 125         if (!page)
 126                 return NULL;
 127
 128         phys = page_to_phys(page);
 129         *handle = phys;
 130
 131         /* Now, map the page into P3 with write-combining turned on */
 132         return __ioremap(phys, size, _PAGE_BUFFER);
 133 }
 134 EXPORT_SYMBOL(dma_alloc_writecombine);
 135
 136 void dma_free_writecombine(struct device *dev, size_t size,
 137                            void *cpu_addr, dma_addr_t handle)
 138 {
 139         struct page *page;
 140
 141         iounmap(cpu_addr);
 142
 143         page = phys_to_page(handle);
 144         __dma_free(dev, size, page, handle);
 145 }
 146 EXPORT_SYMBOL(dma_free_writecombine);