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 #include <linux/export.h>
  12 #include <linux/mm.h>
  13 #include <linux/device.h>
  14 #include <linux/scatterlist.h>
  15
  16 #include <asm/processor.h>
  17 #include <asm/cacheflush.h>
  18 #include <asm/io.h>
  19 #include <asm/addrspace.h>
  20
  21 void dma_cache_sync(struct device *dev, void *vaddr, size_t size, int direction)
  22 {
  23         /*
  24          * No need to sync an uncached area
  25          */
  26         if (PXSEG(vaddr) == P2SEG)
  27                 return;
  28
  29         switch (direction) {
  30         case DMA_FROM_DEVICE:           /* invalidate only */
  31                 invalidate_dcache_region(vaddr, size);
  32                 break;
  33         case DMA_TO_DEVICE:             /* writeback only */
  34                 clean_dcache_region(vaddr, size);
  35                 break;
  36         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
  37                 flush_dcache_region(vaddr, size);
  38                 break;
  39         default:
  40                 BUG();
  41         }
  42 }
  43 EXPORT_SYMBOL(dma_cache_sync);
  44
  45 static struct page *__dma_alloc(struct device *dev, size_t size,
  46                                 dma_addr_t *handle, gfp_t gfp)
  47 {
  48         struct page *page, *free, *end;
  49         int order;
  50
  51         /* Following is a work-around (a.k.a. hack) to prevent pages
  52          * with __GFP_COMP being passed to split_page() which cannot
  53          * handle them.  The real problem is that this flag probably
  54          * should be 0 on AVR32 as it is not supported on this
  55          * platform--see CONFIG_HUGETLB_PAGE. */
  56         gfp &= ~(__GFP_COMP);
  57
  58         size = PAGE_ALIGN(size);
  59         order = get_order(size);
  60
  61         page = alloc_pages(gfp, order);
  62         if (!page)
  63                 return NULL;
  64         split_page(page, order);
  65
  66         /*
  67          * When accessing physical memory with valid cache data, we
  68          * get a cache hit even if the virtual memory region is marked
  69          * as uncached.
  70          *
  71          * Since the memory is newly allocated, there is no point in
  72          * doing a writeback. If the previous owner cares, he should
  73          * have flushed the cache before releasing the memory.
  74          */
  75         invalidate_dcache_region(phys_to_virt(page_to_phys(page)), size);
  76
  77         *handle = page_to_bus(page);
  78         free = page + (size >> PAGE_SHIFT);
  79         end = page + (1 << order);
  80
  81         /*
  82          * Free any unused pages
  83          */
  84         while (free < end) {
  85                 __free_page(free);
  86                 free++;
  87         }
  88
  89         return page;
  90 }
  91
  92 static void __dma_free(struct device *dev, size_t size,
  93                        struct page *page, dma_addr_t handle)
  94 {
  95         struct page *end = page + (PAGE_ALIGN(size) >> PAGE_SHIFT);
  96
  97         while (page < end)
  98                 __free_page(page++);
  99 }
 100
 101 static void *avr32_dma_alloc(struct device *dev, size_t size,
 102                 dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
 103 {
 104         struct page *page;
 105         dma_addr_t phys;
 106
 107         page = __dma_alloc(dev, size, handle, gfp);
 108         if (!page)
 109                 return NULL;
 110         phys = page_to_phys(page);
 111
 112         if (attrs & DMA_ATTR_WRITE_COMBINE) {
 113                 /* Now, map the page into P3 with write-combining turned on */
 114                 *handle = phys;
 115                 return __ioremap(phys, size, _PAGE_BUFFER);
 116         } else {
 117                 return phys_to_uncached(phys);
 118         }
 119 }
 120
 121 static void avr32_dma_free(struct device *dev, size_t size,
 122                 void *cpu_addr, dma_addr_t handle, unsigned long attrs)
 123 {
 124         struct page *page;
 125
 126         if (attrs & DMA_ATTR_WRITE_COMBINE) {
 127                 iounmap(cpu_addr);
 128
 129                 page = phys_to_page(handle);
 130         } else {
 131                 void *addr = phys_to_cached(uncached_to_phys(cpu_addr));
 132
 133                 pr_debug("avr32_dma_free addr %p (phys %08lx) size %u\n",
 134                          cpu_addr, (unsigned long)handle, (unsigned)size);
 135
 136                 BUG_ON(!virt_addr_valid(addr));
 137                 page = virt_to_page(addr);
 138         }
 139
 140         __dma_free(dev, size, page, handle);
 141 }
 142
 143 static dma_addr_t avr32_dma_map_page(struct device *dev, struct page *page,
 144                 unsigned long offset, size_t size,
 145                 enum dma_data_direction direction, unsigned long attrs)
 146 {
 147         void *cpu_addr = page_address(page) + offset;
 148
 149         dma_cache_sync(dev, cpu_addr, size, direction);
 150         return virt_to_bus(cpu_addr);
 151 }
 152
 153 static int avr32_dma_map_sg(struct device *dev, struct scatterlist *sglist,
 154                 int nents, enum dma_data_direction direction,
 155                 unsigned long attrs)
 156 {
 157         int i;
 158         struct scatterlist *sg;
 159
 160         for_each_sg(sglist, sg, nents, i) {
 161                 char *virt;
 162
 163                 sg->dma_address = page_to_bus(sg_page(sg)) + sg->offset;
 164                 virt = sg_virt(sg);
 165                 dma_cache_sync(dev, virt, sg->length, direction);
 166         }
 167
 168         return nents;
 169 }
 170
 171 static void avr32_dma_sync_single_for_device(struct device *dev,
 172                 dma_addr_t dma_handle, size_t size,
 173                 enum dma_data_direction direction)
 174 {
 175         dma_cache_sync(dev, bus_to_virt(dma_handle), size, direction);
 176 }
 177
 178 static void avr32_dma_sync_sg_for_device(struct device *dev,
 179                 struct scatterlist *sglist, int nents,
 180                 enum dma_data_direction direction)
 181 {
 182         int i;
 183         struct scatterlist *sg;
 184
 185         for_each_sg(sglist, sg, nents, i)
 186                 dma_cache_sync(dev, sg_virt(sg), sg->length, direction);
 187 }
 188
 189 struct dma_map_ops avr32_dma_ops = {
 190         .alloc                  = avr32_dma_alloc,
 191         .free                   = avr32_dma_free,
 192         .map_page               = avr32_dma_map_page,
 193         .map_sg                 = avr32_dma_map_sg,
 194         .sync_single_for_device = avr32_dma_sync_single_for_device,
 195         .sync_sg_for_device     = avr32_dma_sync_sg_for_device,
 196 };
 197 EXPORT_SYMBOL(avr32_dma_ops);