2 * Dynamic DMA mapping support.
4 * On i386 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
10 #include <linux/types.h>
12 #include <linux/string.h>
13 #include <linux/pci.h>
14 #include <linux/module.h>
17 /* For i386, we make it point to the NULL address */
18 dma_addr_t bad_dma_address __read_mostly
= 0x0;
19 EXPORT_SYMBOL(bad_dma_address
);
21 void *dma_alloc_coherent(struct device
*dev
, size_t size
,
22 dma_addr_t
*dma_handle
, gfp_t gfp
)
25 struct dma_coherent_mem
*mem
= dev
? dev
->dma_mem
: NULL
;
26 int order
= get_order(size
);
27 /* ignore region specifiers */
28 gfp
&= ~(__GFP_DMA
| __GFP_HIGHMEM
);
31 int page
= bitmap_find_free_region(mem
->bitmap
, mem
->size
,
34 *dma_handle
= mem
->device_base
+ (page
<< PAGE_SHIFT
);
35 ret
= mem
->virt_base
+ (page
<< PAGE_SHIFT
);
39 if (mem
->flags
& DMA_MEMORY_EXCLUSIVE
)
43 if (dev
== NULL
|| (dev
->coherent_dma_mask
< 0xffffffff))
46 ret
= (void *)__get_free_pages(gfp
, order
);
50 *dma_handle
= virt_to_phys(ret
);
54 EXPORT_SYMBOL(dma_alloc_coherent
);
56 void dma_free_coherent(struct device
*dev
, size_t size
,
57 void *vaddr
, dma_addr_t dma_handle
)
59 struct dma_coherent_mem
*mem
= dev
? dev
->dma_mem
: NULL
;
60 int order
= get_order(size
);
62 WARN_ON(irqs_disabled()); /* for portability */
63 if (mem
&& vaddr
>= mem
->virt_base
&& vaddr
< (mem
->virt_base
+ (mem
->size
<< PAGE_SHIFT
))) {
64 int page
= (vaddr
- mem
->virt_base
) >> PAGE_SHIFT
;
66 bitmap_release_region(mem
->bitmap
, page
, order
);
68 free_pages((unsigned long)vaddr
, order
);
70 EXPORT_SYMBOL(dma_free_coherent
);