| 1 | |
| 2 | |
| 3 | * Copyright (c) 2014 The Linux Foundation
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| 4 |
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| 5 | #include <linux/dma-map-ops.h>
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| 6 | #include <linux/slab.h>
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| 7 | #include <linux/vmalloc.h>
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| 8 |
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| 9 | struct page **dma_common_find_pages(void *cpu_addr)
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| 10 | {
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| 11 | struct vm_struct *area = find_vm_area(cpu_addr);
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| 12 |
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| 13 | if (!area || !(area->flags & VM_DMA_COHERENT))
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| 14 | return NULL;
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| 15 | WARN(area->flags != VM_DMA_COHERENT,
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| 16 | "unexpected flags in area: %p\n", cpu_addr);
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| 17 | return area->pages;
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| 18 | }
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| 19 |
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| 20 | |
| 21 | * Remaps an array of PAGE_SIZE pages into another vm_area.
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| 22 | * Cannot be used in non-sleeping contexts
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| 23 |
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| 24 | void *dma_common_pages_remap(struct page **pages, size_t size,
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| 25 | pgprot_t prot, const void *caller)
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| 26 | {
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| 27 | void *vaddr;
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| 28 |
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| 29 | vaddr = vmap(pages, PAGE_ALIGN(size) >> PAGE_SHIFT,
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| 30 | VM_DMA_COHERENT, prot);
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| 31 | if (vaddr)
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| 32 | find_vm_area(vaddr)->pages = pages;
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| 33 | return vaddr;
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| 34 | }
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| 35 |
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| 36 | |
| 37 | * Remaps an allocated contiguous region into another vm_area.
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| 38 | * Cannot be used in non-sleeping contexts
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| 39 |
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| 40 | void *dma_common_contiguous_remap(struct page *page, size_t size,
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| 41 | pgprot_t prot, const void *caller)
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| 42 | {
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| 43 | int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
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| 44 | struct page **pages;
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| 45 | void *vaddr;
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| 46 | int i;
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| 47 |
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| 48 | pages = kvmalloc_objs(struct page *, count);
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| 49 | if (!pages)
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| 50 | return NULL;
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| 51 | for (i = 0; i < count; i++)
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| 52 | pages[i] = page++;
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| 53 | vaddr = vmap(pages, count, VM_DMA_COHERENT, prot);
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| 54 | kvfree(pages);
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| 55 |
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| 56 | return vaddr;
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| 57 | }
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| 58 |
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| 59 | |
| 60 | * Unmaps a range previously mapped by dma_common_*_remap
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| 61 |
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| 62 | void dma_common_free_remap(void *cpu_addr, size_t size)
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| 63 | {
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| 64 | struct vm_struct *area = find_vm_area(cpu_addr);
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| 65 |
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| 66 | if (!area || !(area->flags & VM_DMA_COHERENT)) {
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| 67 | WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
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| 68 | return;
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| 69 | }
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| 70 |
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| 71 | vunmap(cpu_addr);
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| 72 | }
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