arch/cris/arch-v32/drivers/pci/dma.c

   1 /*
   2  * Dynamic DMA mapping support.
   3  *
   4  * On cris there is no hardware dynamic DMA address translation,
   5  * so consistent alloc/free are merely page allocation/freeing.
   6  * The rest of the dynamic DMA mapping interface is implemented
   7  * in asm/pci.h.
   8  *
   9  * Borrowed from i386.
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/mm.h>
  14 #include <linux/string.h>
  15 #include <linux/pci.h>
  16 #include <asm/io.h>
  17
  18 struct dma_coherent_mem {
  19         void            *virt_base;
  20         u32             device_base;
  21         int             size;
  22         int             flags;
  23         unsigned long   *bitmap;
  24 };
  25
  26 void *dma_alloc_coherent(struct device *dev, size_t size,
  27                            dma_addr_t *dma_handle, gfp_t gfp)
  28 {
  29         void *ret;
  30         struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
  31         int order = get_order(size);
  32         /* ignore region specifiers */
  33         gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  34
  35         if (mem) {
  36                 int page = bitmap_find_free_region(mem->bitmap, mem->size,
  37                                                      order);
  38                 if (page >= 0) {
  39                         *dma_handle = mem->device_base + (page << PAGE_SHIFT);
  40                         ret = mem->virt_base + (page << PAGE_SHIFT);
  41                         memset(ret, 0, size);
  42                         return ret;
  43                 }
  44                 if (mem->flags & DMA_MEMORY_EXCLUSIVE)
  45                         return NULL;
  46         }
  47
  48         if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
  49                 gfp |= GFP_DMA;
  50
  51         ret = (void *)__get_free_pages(gfp, order);
  52
  53         if (ret != NULL) {
  54                 memset(ret, 0, size);
  55                 *dma_handle = virt_to_phys(ret);
  56         }
  57         return ret;
  58 }
  59
  60 void dma_free_coherent(struct device *dev, size_t size,
  61                          void *vaddr, dma_addr_t dma_handle)
  62 {
  63         struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
  64         int order = get_order(size);
  65
  66         if (mem && vaddr >= mem->virt_base && vaddr < (mem->virt_base + (mem->size << PAGE_SHIFT))) {
  67                 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
  68
  69                 bitmap_release_region(mem->bitmap, page, order);
  70         } else
  71                 free_pages((unsigned long)vaddr, order);
  72 }
  73
  74 int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
  75                                 dma_addr_t device_addr, size_t size, int flags)
  76 {
  77         void __iomem *mem_base;
  78         int pages = size >> PAGE_SHIFT;
  79         int bitmap_size = (pages + 31)/32;
  80
  81         if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
  82                 goto out;
  83         if (!size)
  84                 goto out;
  85         if (dev->dma_mem)
  86                 goto out;
  87
  88         /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
  89
  90         mem_base = ioremap(bus_addr, size);
  91         if (!mem_base)
  92                 goto out;
  93
  94         dev->dma_mem = kmalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
  95         if (!dev->dma_mem)
  96                 goto out;
  97         memset(dev->dma_mem, 0, sizeof(struct dma_coherent_mem));
  98         dev->dma_mem->bitmap = kmalloc(bitmap_size, GFP_KERNEL);
  99         if (!dev->dma_mem->bitmap)
 100                 goto free1_out;
 101         memset(dev->dma_mem->bitmap, 0, bitmap_size);
 102
 103         dev->dma_mem->virt_base = mem_base;
 104         dev->dma_mem->device_base = device_addr;
 105         dev->dma_mem->size = pages;
 106         dev->dma_mem->flags = flags;
 107
 108         if (flags & DMA_MEMORY_MAP)
 109                 return DMA_MEMORY_MAP;
 110
 111         return DMA_MEMORY_IO;
 112
 113  free1_out:
 114         kfree(dev->dma_mem->bitmap);
 115  out:
 116         return 0;
 117 }
 118 EXPORT_SYMBOL(dma_declare_coherent_memory);
 119
 120 void dma_release_declared_memory(struct device *dev)
 121 {
 122         struct dma_coherent_mem *mem = dev->dma_mem;
 123
 124         if(!mem)
 125                 return;
 126         dev->dma_mem = NULL;
 127         iounmap(mem->virt_base);
 128         kfree(mem->bitmap);
 129         kfree(mem);
 130 }
 131 EXPORT_SYMBOL(dma_release_declared_memory);
 132
 133 void *dma_mark_declared_memory_occupied(struct device *dev,
 134                                         dma_addr_t device_addr, size_t size)
 135 {
 136         struct dma_coherent_mem *mem = dev->dma_mem;
 137         int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT;
 138         int pos, err;
 139
 140         if (!mem)
 141                 return ERR_PTR(-EINVAL);
 142
 143         pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
 144         err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));
 145         if (err != 0)
 146                 return ERR_PTR(err);
 147         return mem->virt_base + (pos << PAGE_SHIFT);
 148 }
 149 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);