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(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(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] = nth_page(page, i);
53	vaddr = vmap(pages, count, VM_DMA_COHERENT, prot);
54	kvfree(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(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(cpu_addr);
72}