1 // SPDX-License-Identifier: GPL-2.0
3 * DMABUF CMA heap exporter
5 * Copyright (C) 2012, 2019 Linaro Ltd.
6 * Author: <benjamin.gaignard@linaro.org> for ST-Ericsson.
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>
22 #include "heap-helpers.h"
25 struct dma_heap *heap;
29 static void cma_heap_free(struct heap_helper_buffer *buffer)
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;
38 cma_release(cma_heap->cma, cma_pages, nr_pages);
42 /* dmabuf heap CMA operations functions */
43 static int cma_heap_allocate(struct dma_heap *heap,
45 unsigned long fd_flags,
46 unsigned long heap_flags)
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;
58 if (align > CONFIG_CMA_ALIGNMENT)
59 align = CONFIG_CMA_ALIGNMENT;
61 helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL);
65 init_heap_helper_buffer(helper_buffer, cma_heap_free);
66 helper_buffer->heap = heap;
67 helper_buffer->size = len;
69 cma_pages = cma_alloc(cma_heap->cma, nr_pages, align, false);
73 if (PageHighMem(cma_pages)) {
74 unsigned long nr_clear_pages = nr_pages;
75 struct page *page = cma_pages;
77 while (nr_clear_pages > 0) {
78 void *vaddr = kmap_atomic(page);
80 memset(vaddr, 0, PAGE_SIZE);
83 * Avoid wasting time zeroing memory if the process
84 * has been killed by by SIGKILL
86 if (fatal_signal_pending(current))
93 memset(page_address(cma_pages), 0, size);
96 helper_buffer->pagecount = nr_pages;
97 helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
98 sizeof(*helper_buffer->pages),
100 if (!helper_buffer->pages) {
105 for (pg = 0; pg < helper_buffer->pagecount; pg++)
106 helper_buffer->pages[pg] = &cma_pages[pg];
108 /* create the dmabuf */
109 dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
110 if (IS_ERR(dmabuf)) {
111 ret = PTR_ERR(dmabuf);
115 helper_buffer->dmabuf = dmabuf;
116 helper_buffer->priv_virt = cma_pages;
118 ret = dma_buf_fd(dmabuf, fd_flags);
121 /* just return, as put will call release and that will free */
128 kfree(helper_buffer->pages);
130 cma_release(cma_heap->cma, cma_pages, nr_pages);
132 kfree(helper_buffer);
136 static const struct dma_heap_ops cma_heap_ops = {
137 .allocate = cma_heap_allocate,
140 static int __add_cma_heap(struct cma *cma, void *data)
142 struct cma_heap *cma_heap;
143 struct dma_heap_export_info exp_info;
145 cma_heap = kzalloc(sizeof(*cma_heap), GFP_KERNEL);
150 exp_info.name = cma_get_name(cma);
151 exp_info.ops = &cma_heap_ops;
152 exp_info.priv = cma_heap;
154 cma_heap->heap = dma_heap_add(&exp_info);
155 if (IS_ERR(cma_heap->heap)) {
156 int ret = PTR_ERR(cma_heap->heap);
165 static int add_default_cma_heap(void)
167 struct cma *default_cma = dev_get_cma_area(NULL);
171 ret = __add_cma_heap(default_cma, NULL);
175 module_init(add_default_cma_heap);
176 MODULE_DESCRIPTION("DMA-BUF CMA Heap");
177 MODULE_LICENSE("GPL v2");