1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2014 The Linux Foundation
4 */
5 #include <linux/dma-map-ops.h>
6 #include <linux/slab.h>
7 #include <linux/vmalloc.h>
8
dma_common_find_pages(void * cpu_addr)9 struct page **dma_common_find_pages(void *cpu_addr)
10 {
11 struct vm_struct *area = find_vm_area(cpu_addr);
12
13 if (!area || area->flags != VM_DMA_COHERENT)
14 return NULL;
15 return area->pages;
16 }
17
18 /*
19 * Remaps an array of PAGE_SIZE pages into another vm_area.
20 * Cannot be used in non-sleeping contexts
21 */
dma_common_pages_remap(struct page ** pages,size_t size,pgprot_t prot,const void * caller)22 void *dma_common_pages_remap(struct page **pages, size_t size,
23 pgprot_t prot, const void *caller)
24 {
25 void *vaddr;
26
27 vaddr = vmap(pages, PAGE_ALIGN(size) >> PAGE_SHIFT,
28 VM_DMA_COHERENT, prot);
29 if (vaddr)
30 find_vm_area(vaddr)->pages = pages;
31 return vaddr;
32 }
33
34 /*
35 * Remaps an allocated contiguous region into another vm_area.
36 * Cannot be used in non-sleeping contexts
37 */
dma_common_contiguous_remap(struct page * page,size_t size,pgprot_t prot,const void * caller)38 void *dma_common_contiguous_remap(struct page *page, size_t size,
39 pgprot_t prot, const void *caller)
40 {
41 int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
42 struct page **pages;
43 void *vaddr;
44 int i;
45
46 pages = kmalloc_array(count, sizeof(struct page *), GFP_KERNEL);
47 if (!pages)
48 return NULL;
49 for (i = 0; i < count; i++)
50 pages[i] = nth_page(page, i);
51 vaddr = vmap(pages, count, VM_DMA_COHERENT, prot);
52 kfree(pages);
53
54 return vaddr;
55 }
56
57 /*
58 * Unmaps a range previously mapped by dma_common_*_remap
59 */
dma_common_free_remap(void * cpu_addr,size_t size)60 void dma_common_free_remap(void *cpu_addr, size_t size)
61 {
62 struct vm_struct *area = find_vm_area(cpu_addr);
63
64 if (!area || area->flags != VM_DMA_COHERENT) {
65 WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
66 return;
67 }
68
69 vunmap(cpu_addr);
70 }
71