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, *ret_nocache;
  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         if (!ret)
  48                 return NULL;
  49
  50         memset(ret, 0, size);
  51         /*
  52          * Pages from the page allocator may have data present in
  53          * cache. So flush the cache before using uncached memory.
  54          */
  55         dma_cache_sync(dev, ret, size, DMA_BIDIRECTIONAL);
  56
  57         ret_nocache = ioremap_nocache(virt_to_phys(ret), size);
  58         if (!ret_nocache) {
  59                 free_pages((unsigned long)ret, order);
  60                 return NULL;
  61         }
  62
  63         *dma_handle = virt_to_phys(ret);
  64         return ret_nocache;
  65 }
  66 EXPORT_SYMBOL(dma_alloc_coherent);
  67
  68 void dma_free_coherent(struct device *dev, size_t size,
  69                          void *vaddr, dma_addr_t dma_handle)
  70 {
  71         struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
  72         int order = get_order(size);
  73
  74         if (mem && vaddr >= mem->virt_base && vaddr < (mem->virt_base + (mem->size << PAGE_SHIFT))) {
  75                 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
  76
  77                 bitmap_release_region(mem->bitmap, page, order);
  78         } else {
  79                 WARN_ON(irqs_disabled());       /* for portability */
  80                 BUG_ON(mem && mem->flags & DMA_MEMORY_EXCLUSIVE);
  81                 free_pages((unsigned long)phys_to_virt(dma_handle), order);
  82                 iounmap(vaddr);
  83         }
  84 }
  85 EXPORT_SYMBOL(dma_free_coherent);
  86
  87 int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
  88                                 dma_addr_t device_addr, size_t size, int flags)
  89 {
  90         void __iomem *mem_base = NULL;
  91         int pages = size >> PAGE_SHIFT;
  92         int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
  93
  94         if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
  95                 goto out;
  96         if (!size)
  97                 goto out;
  98         if (dev->dma_mem)
  99                 goto out;
 100
 101         /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
 102
 103         mem_base = ioremap_nocache(bus_addr, size);
 104         if (!mem_base)
 105                 goto out;
 106
 107         dev->dma_mem = kmalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
 108         if (!dev->dma_mem)
 109                 goto out;
 110         dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
 111         if (!dev->dma_mem->bitmap)
 112                 goto free1_out;
 113
 114         dev->dma_mem->virt_base = mem_base;
 115         dev->dma_mem->device_base = device_addr;
 116         dev->dma_mem->size = pages;
 117         dev->dma_mem->flags = flags;
 118
 119         if (flags & DMA_MEMORY_MAP)
 120                 return DMA_MEMORY_MAP;
 121
 122         return DMA_MEMORY_IO;
 123
 124  free1_out:
 125         kfree(dev->dma_mem);
 126  out:
 127         if (mem_base)
 128                 iounmap(mem_base);
 129         return 0;
 130 }
 131 EXPORT_SYMBOL(dma_declare_coherent_memory);
 132
 133 void dma_release_declared_memory(struct device *dev)
 134 {
 135         struct dma_coherent_mem *mem = dev->dma_mem;
 136
 137         if (!mem)
 138                 return;
 139         dev->dma_mem = NULL;
 140         iounmap(mem->virt_base);
 141         kfree(mem->bitmap);
 142         kfree(mem);
 143 }
 144 EXPORT_SYMBOL(dma_release_declared_memory);
 145
 146 void *dma_mark_declared_memory_occupied(struct device *dev,
 147                                         dma_addr_t device_addr, size_t size)
 148 {
 149         struct dma_coherent_mem *mem = dev->dma_mem;
 150         int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT;
 151         int pos, err;
 152
 153         if (!mem)
 154                 return ERR_PTR(-EINVAL);
 155
 156         pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
 157         err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));
 158         if (err != 0)
 159                 return ERR_PTR(err);
 160         return mem->virt_base + (pos << PAGE_SHIFT);
 161 }
 162 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
 163
 164 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 165                     enum dma_data_direction direction)
 166 {
 167 #ifdef CONFIG_CPU_SH5
 168         void *p1addr = vaddr;
 169 #else
 170         void *p1addr = (void*) P1SEGADDR((unsigned long)vaddr);
 171 #endif
 172
 173         switch (direction) {
 174         case DMA_FROM_DEVICE:           /* invalidate only */
 175                 __flush_invalidate_region(p1addr, size);
 176                 break;
 177         case DMA_TO_DEVICE:             /* writeback only */
 178                 __flush_wback_region(p1addr, size);
 179                 break;
 180         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
 181                 __flush_purge_region(p1addr, size);
 182                 break;
 183         default:
 184                 BUG();
 185         }
 186 }
 187 EXPORT_SYMBOL(dma_cache_sync);