release/src-rt-6.x/linux/linux-2.6/arch/powerpc/kernel/dma_64.c

   1 /*
   2  * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
   3  *
   4  * Provide default implementations of the DMA mapping callbacks for
   5  * directly mapped busses and busses using the iommu infrastructure
   6  */
   7
   8 #include <linux/device.h>
   9 #include <linux/dma-mapping.h>
  10 #include <asm/bug.h>
  11 #include <asm/iommu.h>
  12 #include <asm/abs_addr.h>
  13
  14 /*
  15  * Generic iommu implementation
  16  */
  17
  18 static inline unsigned long device_to_mask(struct device *dev)
  19 {
  20         if (dev->dma_mask && *dev->dma_mask)
  21                 return *dev->dma_mask;
  22         /* Assume devices without mask can take 32 bit addresses */
  23         return 0xfffffffful;
  24 }
  25
  26
  27 /* Allocates a contiguous real buffer and creates mappings over it.
  28  * Returns the virtual address of the buffer and sets dma_handle
  29  * to the dma address (mapping) of the first page.
  30  */
  31 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
  32                                       dma_addr_t *dma_handle, gfp_t flag)
  33 {
  34         return iommu_alloc_coherent(dev->archdata.dma_data, size, dma_handle,
  35                                     device_to_mask(dev), flag,
  36                                     dev->archdata.numa_node);
  37 }
  38
  39 static void dma_iommu_free_coherent(struct device *dev, size_t size,
  40                                     void *vaddr, dma_addr_t dma_handle)
  41 {
  42         iommu_free_coherent(dev->archdata.dma_data, size, vaddr, dma_handle);
  43 }
  44
  45 /* Creates TCEs for a user provided buffer.  The user buffer must be
  46  * contiguous real kernel storage (not vmalloc).  The address of the buffer
  47  * passed here is the kernel (virtual) address of the buffer.  The buffer
  48  * need not be page aligned, the dma_addr_t returned will point to the same
  49  * byte within the page as vaddr.
  50  */
  51 static dma_addr_t dma_iommu_map_single(struct device *dev, void *vaddr,
  52                                        size_t size,
  53                                        enum dma_data_direction direction)
  54 {
  55         return iommu_map_single(dev->archdata.dma_data, vaddr, size,
  56                                 device_to_mask(dev), direction);
  57 }
  58
  59
  60 static void dma_iommu_unmap_single(struct device *dev, dma_addr_t dma_handle,
  61                                    size_t size,
  62                                    enum dma_data_direction direction)
  63 {
  64         iommu_unmap_single(dev->archdata.dma_data, dma_handle, size, direction);
  65 }
  66
  67
  68 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
  69                             int nelems, enum dma_data_direction direction)
  70 {
  71         return iommu_map_sg(dev->archdata.dma_data, sglist, nelems,
  72                             device_to_mask(dev), direction);
  73 }
  74
  75 static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
  76                 int nelems, enum dma_data_direction direction)
  77 {
  78         iommu_unmap_sg(dev->archdata.dma_data, sglist, nelems, direction);
  79 }
  80
  81 /* We support DMA to/from any memory page via the iommu */
  82 static int dma_iommu_dma_supported(struct device *dev, u64 mask)
  83 {
  84         struct iommu_table *tbl = dev->archdata.dma_data;
  85
  86         if (!tbl || tbl->it_offset > mask) {
  87                 printk(KERN_INFO
  88                        "Warning: IOMMU offset too big for device mask\n");
  89                 if (tbl)
  90                         printk(KERN_INFO
  91                                "mask: 0x%08lx, table offset: 0x%08lx\n",
  92                                 mask, tbl->it_offset);
  93                 else
  94                         printk(KERN_INFO "mask: 0x%08lx, table unavailable\n",
  95                                 mask);
  96                 return 0;
  97         } else
  98                 return 1;
  99 }
 100
 101 struct dma_mapping_ops dma_iommu_ops = {
 102         .alloc_coherent = dma_iommu_alloc_coherent,
 103         .free_coherent  = dma_iommu_free_coherent,
 104         .map_single     = dma_iommu_map_single,
 105         .unmap_single   = dma_iommu_unmap_single,
 106         .map_sg         = dma_iommu_map_sg,
 107         .unmap_sg       = dma_iommu_unmap_sg,
 108         .dma_supported  = dma_iommu_dma_supported,
 109 };
 110 EXPORT_SYMBOL(dma_iommu_ops);
 111
 112 /*
 113  * Generic direct DMA implementation
 114  *
 115  * This implementation supports a global offset that can be applied if
 116  * the address at which memory is visible to devices is not 0.
 117  */
 118 unsigned long dma_direct_offset;
 119
 120 static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
 121                                        dma_addr_t *dma_handle, gfp_t flag)
 122 {
 123         struct page *page;
 124         void *ret;
 125         int node = dev->archdata.numa_node;
 126
 127         /* TODO: Maybe use the numa node here too ? */
 128         page = alloc_pages_node(node, flag, get_order(size));
 129         if (page == NULL)
 130                 return NULL;
 131         ret = page_address(page);
 132         memset(ret, 0, size);
 133         *dma_handle = virt_to_abs(ret) | dma_direct_offset;
 134
 135         return ret;
 136 }
 137
 138 static void dma_direct_free_coherent(struct device *dev, size_t size,
 139                                      void *vaddr, dma_addr_t dma_handle)
 140 {
 141         free_pages((unsigned long)vaddr, get_order(size));
 142 }
 143
 144 static dma_addr_t dma_direct_map_single(struct device *dev, void *ptr,
 145                                         size_t size,
 146                                         enum dma_data_direction direction)
 147 {
 148         return virt_to_abs(ptr) | dma_direct_offset;
 149 }
 150
 151 static void dma_direct_unmap_single(struct device *dev, dma_addr_t dma_addr,
 152                                     size_t size,
 153                                     enum dma_data_direction direction)
 154 {
 155 }
 156
 157 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sg,
 158                              int nents, enum dma_data_direction direction)
 159 {
 160         int i;
 161
 162         for (i = 0; i < nents; i++, sg++) {
 163                 sg->dma_address = (page_to_phys(sg->page) + sg->offset) |
 164                         dma_direct_offset;
 165                 sg->dma_length = sg->length;
 166         }
 167
 168         return nents;
 169 }
 170
 171 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
 172                                 int nents, enum dma_data_direction direction)
 173 {
 174 }
 175
 176 static int dma_direct_dma_supported(struct device *dev, u64 mask)
 177 {
 178         /* Could be improved to check for memory though it better be
 179          * done via some global so platforms can set the limit in case
 180          * they have limited DMA windows
 181          */
 182         return mask >= DMA_32BIT_MASK;
 183 }
 184
 185 struct dma_mapping_ops dma_direct_ops = {
 186         .alloc_coherent = dma_direct_alloc_coherent,
 187         .free_coherent  = dma_direct_free_coherent,
 188         .map_single     = dma_direct_map_single,
 189         .unmap_single   = dma_direct_unmap_single,
 190         .map_sg         = dma_direct_map_sg,
 191         .unmap_sg       = dma_direct_unmap_sg,
 192         .dma_supported  = dma_direct_dma_supported,
 193 };
 194 EXPORT_SYMBOL(dma_direct_ops);