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