2e33e36118
We call unmap_single, if available. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
87 lines
2.2 KiB
C
87 lines
2.2 KiB
C
/*
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* Dynamic DMA mapping support.
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*
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* On i386 there is no hardware dynamic DMA address translation,
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* so consistent alloc/free are merely page allocation/freeing.
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* The rest of the dynamic DMA mapping interface is implemented
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* in asm/pci.h.
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*/
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/pci.h>
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#include <linux/module.h>
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#include <asm/io.h>
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static int dma_alloc_from_coherent_mem(struct device *dev, ssize_t size,
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dma_addr_t *dma_handle, void **ret)
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{
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struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
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int order = get_order(size);
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if (mem) {
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int page = bitmap_find_free_region(mem->bitmap, mem->size,
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order);
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if (page >= 0) {
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*dma_handle = mem->device_base + (page << PAGE_SHIFT);
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*ret = mem->virt_base + (page << PAGE_SHIFT);
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memset(*ret, 0, size);
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}
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if (mem->flags & DMA_MEMORY_EXCLUSIVE)
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*ret = NULL;
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}
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return (mem != NULL);
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}
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static int dma_release_coherent(struct device *dev, int order, void *vaddr)
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{
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struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
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if (mem && vaddr >= mem->virt_base && vaddr <
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(mem->virt_base + (mem->size << PAGE_SHIFT))) {
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int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
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bitmap_release_region(mem->bitmap, page, order);
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return 1;
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}
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return 0;
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}
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void *dma_alloc_coherent(struct device *dev, size_t size,
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dma_addr_t *dma_handle, gfp_t gfp)
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{
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void *ret = NULL;
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int order = get_order(size);
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/* ignore region specifiers */
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gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
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if (dma_alloc_from_coherent_mem(dev, size, dma_handle, &ret))
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return ret;
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if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
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gfp |= GFP_DMA;
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ret = (void *)__get_free_pages(gfp, order);
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if (ret != NULL) {
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memset(ret, 0, size);
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*dma_handle = virt_to_phys(ret);
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}
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return ret;
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}
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EXPORT_SYMBOL(dma_alloc_coherent);
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void dma_free_coherent(struct device *dev, size_t size,
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void *vaddr, dma_addr_t dma_handle)
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{
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int order = get_order(size);
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WARN_ON(irqs_disabled()); /* for portability */
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if (dma_release_coherent(dev, order, vaddr))
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return;
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if (dma_ops->unmap_single)
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dma_ops->unmap_single(dev, dma_handle, size, 0);
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free_pages((unsigned long)vaddr, order);
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}
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EXPORT_SYMBOL(dma_free_coherent);
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