arch/sh/mm/consistent.c

   1 /*
   2  * arch/sh/mm/consistent.c
   3  *
   4  * Copyright (C) 2004 - 2007  Paul Mundt
   5  *
   6  * Declared coherent memory functions based on arch/x86/kernel/pci-dma_32.c
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  */
  12 #include <linux/mm.h>
  13 #include <linux/dma-mapping.h>
  14 #include <asm/cacheflush.h>
  15 #include <asm/addrspace.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
  33         if (mem) {
  34                 int page = bitmap_find_free_region(mem->bitmap, mem->size,
  35                                                      order);
  36                 if (page >= 0) {
  37                         *dma_handle = mem->device_base + (page << PAGE_SHIFT);
  38                         ret = mem->virt_base + (page << PAGE_SHIFT);
  39                         memset(ret, 0, size);
  40                         return ret;
  41                 }
  42                 if (mem->flags & DMA_MEMORY_EXCLUSIVE)
  43                         return NULL;
  44         }
  45
  46         ret = (void *)__get_free_pages(gfp, order);
  47
  48         if (ret != NULL) {
  49                 memset(ret, 0, size);
  50                 /*
  51                  * Pages from the page allocator may have data present in
  52                  * cache. So flush the cache before using uncached memory.
  53                  */
  54                 dma_cache_sync(NULL, ret, size, DMA_BIDIRECTIONAL);
  55                 *dma_handle = virt_to_phys(ret);
  56         }
  57         return ret;
  58 }
  59 EXPORT_SYMBOL(dma_alloc_coherent);
  60
  61 void dma_free_coherent(struct device *dev, size_t size,
  62                          void *vaddr, dma_addr_t dma_handle)
  63 {
  64         struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
  65         int order = get_order(size);
  66
  67         if (mem && vaddr >= mem->virt_base && vaddr < (mem->virt_base + (mem->size << PAGE_SHIFT))) {
  68                 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
  69
  70                 bitmap_release_region(mem->bitmap, page, order);
  71         } else {
  72                 WARN_ON(irqs_disabled());       /* for portability */
  73                 BUG_ON(mem && mem->flags & DMA_MEMORY_EXCLUSIVE);
  74                 free_pages((unsigned long)vaddr, order);
  75         }
  76 }
  77 EXPORT_SYMBOL(dma_free_coherent);
  78
  79 int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
  80                                 dma_addr_t device_addr, size_t size, int flags)
  81 {
  82         void __iomem *mem_base = NULL;
  83         int pages = size >> PAGE_SHIFT;
  84         int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
  85
  86         if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
  87                 goto out;
  88         if (!size)
  89                 goto out;
  90         if (dev->dma_mem)
  91                 goto out;
  92
  93         /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
  94
  95         mem_base = ioremap_nocache(bus_addr, size);
  96         if (!mem_base)
  97                 goto out;
  98
  99         dev->dma_mem = kmalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
 100         if (!dev->dma_mem)
 101                 goto out;
 102         dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
 103         if (!dev->dma_mem->bitmap)
 104                 goto free1_out;
 105
 106         dev->dma_mem->virt_base = mem_base;
 107         dev->dma_mem->device_base = device_addr;
 108         dev->dma_mem->size = pages;
 109         dev->dma_mem->flags = flags;
 110
 111         if (flags & DMA_MEMORY_MAP)
 112                 return DMA_MEMORY_MAP;
 113
 114         return DMA_MEMORY_IO;
 115
 116  free1_out:
 117         kfree(dev->dma_mem);
 118  out:
 119         if (mem_base)
 120                 iounmap(mem_base);
 121         return 0;
 122 }
 123 EXPORT_SYMBOL(dma_declare_coherent_memory);
 124
 125 void dma_release_declared_memory(struct device *dev)
 126 {
 127         struct dma_coherent_mem *mem = dev->dma_mem;
 128
 129         if (!mem)
 130                 return;
 131         dev->dma_mem = NULL;
 132         iounmap(mem->virt_base);
 133         kfree(mem->bitmap);
 134         kfree(mem);
 135 }
 136 EXPORT_SYMBOL(dma_release_declared_memory);
 137
 138 void *dma_mark_declared_memory_occupied(struct device *dev,
 139                                         dma_addr_t device_addr, size_t size)
 140 {
 141         struct dma_coherent_mem *mem = dev->dma_mem;
 142         int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT;
 143         int pos, err;
 144
 145         if (!mem)
 146                 return ERR_PTR(-EINVAL);
 147
 148         pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
 149         err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));
 150         if (err != 0)
 151                 return ERR_PTR(err);
 152         return mem->virt_base + (pos << PAGE_SHIFT);
 153 }
 154 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
 155
 156 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 157                     enum dma_data_direction direction)
 158 {
 159 #ifdef CONFIG_CPU_SH5
 160         void *p1addr = vaddr;
 161 #else
 162         void *p1addr = (void*) P1SEGADDR((unsigned long)vaddr);
 163 #endif
 164
 165         switch (direction) {
 166         case DMA_FROM_DEVICE:           /* invalidate only */
 167                 __flush_invalidate_region(p1addr, size);
 168                 break;
 169         case DMA_TO_DEVICE:             /* writeback only */
 170                 __flush_wback_region(p1addr, size);
 171                 break;
 172         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
 173                 __flush_purge_region(p1addr, size);
 174                 break;
 175         default:
 176                 BUG();
 177         }
 178 }
 179 EXPORT_SYMBOL(dma_cache_sync);