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ARM: dma-mapping: functions to allocate/free a coherent buffer 

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Greg Ungerer <gerg@uclinux.org>
This commit is contained in:
Russell King 2009-11-19 15:31:07 +00:00
parent 13ccf3ad99
commit 7a9a32a953
1 changed files with 66 additions and 44 deletions
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110
arch/arm/mm/dma-mapping.c
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@ -63,6 +63,68 @@ static u64 get_coherent_dma_mask(struct device *dev)
return mask;
}
/*
* Allocate a DMA buffer for 'dev' of size 'size' using the
* specified gfp mask. Note that 'size' must be page aligned.
*/
static struct page *__dma_alloc_buffer(struct device *dev, size_t size, gfp_t gfp)
{
unsigned long order = get_order(size);
struct page *page, *p, *e;
void *ptr;
u64 mask = get_coherent_dma_mask(dev);
#ifdef CONFIG_DMA_API_DEBUG
u64 limit = (mask + 1) & ~mask;
if (limit && size >= limit) {
dev_warn(dev, "coherent allocation too big (requested %#x mask %#llx)\n",
size, mask);
return NULL;
}
#endif
if (!mask)
return NULL;
if (mask < 0xffffffffULL)
gfp |= GFP_DMA;
page = alloc_pages(gfp, order);
if (!page)
return NULL;
/*
* Now split the huge page and free the excess pages
*/
split_page(page, order);
for (p = page + (size >> PAGE_SHIFT), e = page + (1 << order); p < e; p++)
__free_page(p);
/*
* Ensure that the allocated pages are zeroed, and that any data
* lurking in the kernel direct-mapped region is invalidated.
*/
ptr = page_address(page);
memset(ptr, 0, size);
dmac_flush_range(ptr, ptr + size);
outer_flush_range(__pa(ptr), __pa(ptr) + size);
return page;
}
/*
* Free a DMA buffer. 'size' must be page aligned.
*/
static void __dma_free_buffer(struct page *page, size_t size)
{
struct page *e = page + (size >> PAGE_SHIFT);
while (page < e) {
__free_page(page);
page++;
}
}
#ifdef CONFIG_MMU
/*
* These are the page tables (2MB each) covering uncached, DMA consistent allocations
@ -88,9 +150,6 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
{
struct page *page;
struct arm_vmregion *c;
unsigned long order;
u64 mask = get_coherent_dma_mask(dev);
u64 limit;
if (!consistent_pte[0]) {
printk(KERN_ERR "%s: not initialised\n", __func__);
@ -98,37 +157,12 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
return NULL;
}
if (!mask)
goto no_page;
size = PAGE_ALIGN(size);
limit = (mask + 1) & ~mask;
if (limit && size >= limit) {
printk(KERN_WARNING "coherent allocation too big "
"(requested %#x mask %#llx)\n", size, mask);
goto no_page;
}
order = get_order(size);
if (mask < 0xffffffffULL)
gfp |= GFP_DMA;
page = alloc_pages(gfp, order);
page = __dma_alloc_buffer(dev, size, gfp);
if (!page)
goto no_page;
/*
* Invalidate any data that might be lurking in the
* kernel direct-mapped region for device DMA.
*/
{
void *ptr = page_address(page);
memset(ptr, 0, size);
dmac_flush_range(ptr, ptr + size);
outer_flush_range(__pa(ptr), __pa(ptr) + size);
}
/*
* Allocate a virtual address in the consistent mapping region.
*/
@ -136,15 +170,12 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
if (c) {
pte_t *pte;
struct page *end = page + (1 << order);
int idx = CONSISTENT_PTE_INDEX(c->vm_start);
u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
pte = consistent_pte[idx] + off;
c->vm_pages = page;
split_page(page, order);
/*
* Set the "dma handle"
*/
@ -167,19 +198,11 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
}
} while (size -= PAGE_SIZE);
/*
* Free the otherwise unused pages.
*/
while (page < end) {
__free_page(page);
page++;
}
return (void *)c->vm_start;
}
if (page)
__free_pages(page, order);
__dma_free_buffer(page, size);
no_page:
*handle = ~0;
return NULL;
@ -357,12 +380,9 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr
* x86 does not mark the pages reserved...
*/
ClearPageReserved(page);
__free_page(page);
continue;
}
}
printk(KERN_CRIT "%s: bad page in kernel page table\n",
__func__);
} while (size -= PAGE_SIZE);
@ -370,6 +390,8 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr
flush_tlb_kernel_range(c->vm_start, c->vm_end);
arm_vmregion_free(&consistent_head, c);
__dma_free_buffer(dma_to_page(dev, handle), size);
return;
no_area: