1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * DMABUF CMA heap exporter
4 *
5 * Copyright (C) 2012, 2019 Linaro Ltd.
6 * Author: <benjamin.gaignard@linaro.org> for ST-Ericsson.
7 */
8
9 #include <linux/cma.h>
10 #include <linux/device.h>
11 #include <linux/dma-buf.h>
12 #include <linux/dma-heap.h>
13 #include <linux/dma-map-ops.h>
14 #include <linux/err.h>
15 #include <linux/errno.h>
16 #include <linux/highmem.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/scatterlist.h>
20 #include <linux/sched/signal.h>
21
22 #include "heap-helpers.h"
23
24 struct cma_heap {
25 struct dma_heap *heap;
26 struct cma *cma;
27 };
28
cma_heap_free(struct heap_helper_buffer * buffer)29 static void cma_heap_free(struct heap_helper_buffer *buffer)
30 {
31 struct cma_heap *cma_heap = dma_heap_get_drvdata(buffer->heap);
32 unsigned long nr_pages = buffer->pagecount;
33 struct page *cma_pages = buffer->priv_virt;
34
35 /* free page list */
36 kfree(buffer->pages);
37 /* release memory */
38 cma_release(cma_heap->cma, cma_pages, nr_pages);
39 kfree(buffer);
40 }
41
42 /* dmabuf heap CMA operations functions */
cma_heap_allocate(struct dma_heap * heap,unsigned long len,unsigned long fd_flags,unsigned long heap_flags)43 static int cma_heap_allocate(struct dma_heap *heap,
44 unsigned long len,
45 unsigned long fd_flags,
46 unsigned long heap_flags)
47 {
48 struct cma_heap *cma_heap = dma_heap_get_drvdata(heap);
49 struct heap_helper_buffer *helper_buffer;
50 struct page *cma_pages;
51 size_t size = PAGE_ALIGN(len);
52 unsigned long nr_pages = size >> PAGE_SHIFT;
53 unsigned long align = get_order(size);
54 struct dma_buf *dmabuf;
55 int ret = -ENOMEM;
56 pgoff_t pg;
57
58 if (align > CONFIG_CMA_ALIGNMENT)
59 align = CONFIG_CMA_ALIGNMENT;
60
61 helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL);
62 if (!helper_buffer)
63 return -ENOMEM;
64
65 init_heap_helper_buffer(helper_buffer, cma_heap_free);
66 helper_buffer->heap = heap;
67 helper_buffer->size = len;
68
69 cma_pages = cma_alloc(cma_heap->cma, nr_pages, align, false);
70 if (!cma_pages)
71 goto free_buf;
72
73 if (PageHighMem(cma_pages)) {
74 unsigned long nr_clear_pages = nr_pages;
75 struct page *page = cma_pages;
76
77 while (nr_clear_pages > 0) {
78 void *vaddr = kmap_atomic(page);
79
80 memset(vaddr, 0, PAGE_SIZE);
81 kunmap_atomic(vaddr);
82 /*
83 * Avoid wasting time zeroing memory if the process
84 * has been killed by by SIGKILL
85 */
86 if (fatal_signal_pending(current))
87 goto free_cma;
88
89 page++;
90 nr_clear_pages--;
91 }
92 } else {
93 memset(page_address(cma_pages), 0, size);
94 }
95
96 helper_buffer->pagecount = nr_pages;
97 helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
98 sizeof(*helper_buffer->pages),
99 GFP_KERNEL);
100 if (!helper_buffer->pages) {
101 ret = -ENOMEM;
102 goto free_cma;
103 }
104
105 for (pg = 0; pg < helper_buffer->pagecount; pg++)
106 helper_buffer->pages[pg] = &cma_pages[pg];
107
108 /* create the dmabuf */
109 dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
110 if (IS_ERR(dmabuf)) {
111 ret = PTR_ERR(dmabuf);
112 goto free_pages;
113 }
114
115 helper_buffer->dmabuf = dmabuf;
116 helper_buffer->priv_virt = cma_pages;
117
118 ret = dma_buf_fd(dmabuf, fd_flags);
119 if (ret < 0) {
120 dma_buf_put(dmabuf);
121 /* just return, as put will call release and that will free */
122 return ret;
123 }
124
125 return ret;
126
127 free_pages:
128 kfree(helper_buffer->pages);
129 free_cma:
130 cma_release(cma_heap->cma, cma_pages, nr_pages);
131 free_buf:
132 kfree(helper_buffer);
133 return ret;
134 }
135
136 static const struct dma_heap_ops cma_heap_ops = {
137 .allocate = cma_heap_allocate,
138 };
139
__add_cma_heap(struct cma * cma,void * data)140 static int __add_cma_heap(struct cma *cma, void *data)
141 {
142 struct cma_heap *cma_heap;
143 struct dma_heap_export_info exp_info;
144
145 cma_heap = kzalloc(sizeof(*cma_heap), GFP_KERNEL);
146 if (!cma_heap)
147 return -ENOMEM;
148 cma_heap->cma = cma;
149
150 exp_info.name = cma_get_name(cma);
151 exp_info.ops = &cma_heap_ops;
152 exp_info.priv = cma_heap;
153
154 cma_heap->heap = dma_heap_add(&exp_info);
155 if (IS_ERR(cma_heap->heap)) {
156 int ret = PTR_ERR(cma_heap->heap);
157
158 kfree(cma_heap);
159 return ret;
160 }
161
162 return 0;
163 }
164
add_default_cma_heap(void)165 static int add_default_cma_heap(void)
166 {
167 struct cma *default_cma = dev_get_cma_area(NULL);
168 int ret = 0;
169
170 if (default_cma)
171 ret = __add_cma_heap(default_cma, NULL);
172
173 return ret;
174 }
175 module_init(add_default_cma_heap);
176 MODULE_DESCRIPTION("DMA-BUF CMA Heap");
177 MODULE_LICENSE("GPL v2");
178
