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x86: isolate coherent mapping functions
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i386 implements the declare coherent memory API, and x86_64 does not
it is reflected in pieces of dma_alloc_coherent and dma_free_coherent.
Those pieces are isolated in separate functions, that are declared
as empty macros in x86_64. This way we can make the code the same.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Glauber Costa authored and Ingo Molnar committed Apr 19, 2008
1 parent 8e8edc6 commit d09d815
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Showing 2 changed files with 45 additions and 17 deletions.
51 changes: 35 additions & 16 deletions arch/x86/kernel/pci-dma_32.c
Original file line number Diff line number Diff line change
Expand Up @@ -18,27 +18,50 @@
dma_addr_t bad_dma_address __read_mostly = 0x0;
EXPORT_SYMBOL(bad_dma_address);

void *dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp)
static int dma_alloc_from_coherent_mem(struct device *dev, ssize_t size,
dma_addr_t *dma_handle, void **ret)
{
void *ret;
struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
int order = get_order(size);
/* ignore region specifiers */
gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);

if (mem) {
int page = bitmap_find_free_region(mem->bitmap, mem->size,
order);
if (page >= 0) {
*dma_handle = mem->device_base + (page << PAGE_SHIFT);
ret = mem->virt_base + (page << PAGE_SHIFT);
memset(ret, 0, size);
return ret;
*ret = mem->virt_base + (page << PAGE_SHIFT);
memset(*ret, 0, size);
}
if (mem->flags & DMA_MEMORY_EXCLUSIVE)
return NULL;
*ret = NULL;
}
return (mem != NULL);
}

static int dma_release_coherent(struct device *dev, int order, void *vaddr)
{
struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;

if (mem && vaddr >= mem->virt_base && vaddr <
(mem->virt_base + (mem->size << PAGE_SHIFT))) {
int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;

bitmap_release_region(mem->bitmap, page, order);
return 1;
}
return 0;
}

void *dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp)
{
void *ret = NULL;
int order = get_order(size);
/* ignore region specifiers */
gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);

if (dma_alloc_from_coherent_mem(dev, size, dma_handle, &ret))
return ret;

if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
gfp |= GFP_DMA;
Expand All @@ -56,15 +79,11 @@ EXPORT_SYMBOL(dma_alloc_coherent);
void dma_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle)
{
struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
int order = get_order(size);

WARN_ON(irqs_disabled()); /* for portability */
if (mem && vaddr >= mem->virt_base && vaddr < (mem->virt_base + (mem->size << PAGE_SHIFT))) {
int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;

bitmap_release_region(mem->bitmap, page, order);
} else
free_pages((unsigned long)vaddr, order);
if (dma_release_coherent(dev, order, vaddr))
return;
free_pages((unsigned long)vaddr, order);
}
EXPORT_SYMBOL(dma_free_coherent);
11 changes: 10 additions & 1 deletion arch/x86/kernel/pci-dma_64.c
Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,8 @@ dma_alloc_pages(struct device *dev, gfp_t gfp, unsigned order)
return page ? page_address(page) : NULL;
}

#define dma_alloc_from_coherent_mem(dev, size, handle, ret) (0)
#define dma_release_coherent(dev, order, vaddr) (0)
/*
* Allocate memory for a coherent mapping.
*/
Expand All @@ -50,6 +52,10 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
unsigned long dma_mask = 0;
u64 bus;


if (dma_alloc_from_coherent_mem(dev, size, dma_handle, &memory))
return memory;

if (!dev)
dev = &fallback_dev;
dma_mask = dev->coherent_dma_mask;
Expand Down Expand Up @@ -141,9 +147,12 @@ EXPORT_SYMBOL(dma_alloc_coherent);
void dma_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t bus)
{
int order = get_order(size);
WARN_ON(irqs_disabled()); /* for portability */
if (dma_release_coherent(dev, order, vaddr))
return;
if (dma_ops->unmap_single)
dma_ops->unmap_single(dev, bus, size, 0);
free_pages((unsigned long)vaddr, get_order(size));
free_pages((unsigned long)vaddr, order);
}
EXPORT_SYMBOL(dma_free_coherent);

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