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
9struct page **dma_common_find_pages(void *cpu_addr)
10{
11 struct vm_struct *area = find_vm_area(addr: cpu_addr);
12
13 if (!area || !(area->flags & VM_DMA_COHERENT))
14 return NULL;
15 WARN(area->flags != VM_DMA_COHERENT,
16 "unexpected flags in area: %p\n", cpu_addr);
17 return area->pages;
18}
19
20/*
21 * Remaps an array of PAGE_SIZE pages into another vm_area.
22 * Cannot be used in non-sleeping contexts
23 */
24void *dma_common_pages_remap(struct page **pages, size_t size,
25 pgprot_t prot, const void *caller)
26{
27 void *vaddr;
28
29 vaddr = vmap(pages, PAGE_ALIGN(size) >> PAGE_SHIFT,
30 VM_DMA_COHERENT, prot);
31 if (vaddr)
32 find_vm_area(addr: vaddr)->pages = pages;
33 return vaddr;
34}
35
36/*
37 * Remaps an allocated contiguous region into another vm_area.
38 * Cannot be used in non-sleeping contexts
39 */
40void *dma_common_contiguous_remap(struct page *page, size_t size,
41 pgprot_t prot, const void *caller)
42{
43 int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
44 struct page **pages;
45 void *vaddr;
46 int i;
47
48 pages = kvmalloc_array(count, sizeof(struct page *), GFP_KERNEL);
49 if (!pages)
50 return NULL;
51 for (i = 0; i < count; i++)
52 pages[i] = page++;
53 vaddr = vmap(pages, count, VM_DMA_COHERENT, prot);
54 kvfree(addr: pages);
55
56 return vaddr;
57}
58
59/*
60 * Unmaps a range previously mapped by dma_common_*_remap
61 */
62void dma_common_free_remap(void *cpu_addr, size_t size)
63{
64 struct vm_struct *area = find_vm_area(addr: cpu_addr);
65
66 if (!area || !(area->flags & VM_DMA_COHERENT)) {
67 WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
68 return;
69 }
70
71 vunmap(addr: cpu_addr);
72}
73