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-contiguous.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
 24struct cma_heap {
 25	struct dma_heap *heap;
 26	struct cma *cma;
 27};
 28
 29static 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 */
 43static 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
127free_pages:
128	kfree(helper_buffer->pages);
129free_cma:
130	cma_release(cma_heap->cma, cma_pages, nr_pages);
131free_buf:
132	kfree(helper_buffer);
133	return ret;
134}
135
136static const struct dma_heap_ops cma_heap_ops = {
137	.allocate = cma_heap_allocate,
138};
139
140static 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
165static 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}
175module_init(add_default_cma_heap);
176MODULE_DESCRIPTION("DMA-BUF CMA Heap");
177MODULE_LICENSE("GPL v2");