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// SPDX-License-Identifier: GPL-2.0
/*
* DMABUF CMA heap exporter
*
* Copyright (C) 2012, 2019 Linaro Ltd.
* Author: <benjamin.gaignard@linaro.org> for ST-Ericsson.
*/
#include <linux/cma.h>
#include <linux/device.h>
#include <linux/dma-buf.h>
#include <linux/dma-heap.h>
#include <linux/dma-contiguous.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/scatterlist.h>
#include <linux/sched/signal.h>
#include "heap-helpers.h"
struct cma_heap {
struct dma_heap *heap;
struct cma *cma;
};
static void cma_heap_free(struct heap_helper_buffer *buffer)
{
struct cma_heap *cma_heap = dma_heap_get_drvdata(buffer->heap);
unsigned long nr_pages = buffer->pagecount;
struct page *cma_pages = buffer->priv_virt;
/* free page list */
kfree(buffer->pages);
/* release memory */
cma_release(cma_heap->cma, cma_pages, nr_pages);
kfree(buffer);
}
/* dmabuf heap CMA operations functions */
static int cma_heap_allocate(struct dma_heap *heap,
unsigned long len,
unsigned long fd_flags,
unsigned long heap_flags)
{
struct cma_heap *cma_heap = dma_heap_get_drvdata(heap);
struct heap_helper_buffer *helper_buffer;
struct page *cma_pages;
size_t size = PAGE_ALIGN(len);
unsigned long nr_pages = size >> PAGE_SHIFT;
unsigned long align = get_order(size);
struct dma_buf *dmabuf;
int ret = -ENOMEM;
pgoff_t pg;
if (align > CONFIG_CMA_ALIGNMENT)
align = CONFIG_CMA_ALIGNMENT;
helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL);
if (!helper_buffer)
return -ENOMEM;
init_heap_helper_buffer(helper_buffer, cma_heap_free);
helper_buffer->heap = heap;
helper_buffer->size = len;
cma_pages = cma_alloc(cma_heap->cma, nr_pages, align, false);
if (!cma_pages)
goto free_buf;
if (PageHighMem(cma_pages)) {
unsigned long nr_clear_pages = nr_pages;
struct page *page = cma_pages;
while (nr_clear_pages > 0) {
void *vaddr = kmap_atomic(page);
memset(vaddr, 0, PAGE_SIZE);
kunmap_atomic(vaddr);
/*
* Avoid wasting time zeroing memory if the process
* has been killed by by SIGKILL
*/
if (fatal_signal_pending(current))
goto free_cma;
page++;
nr_clear_pages--;
}
} else {
memset(page_address(cma_pages), 0, size);
}
helper_buffer->pagecount = nr_pages;
helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
sizeof(*helper_buffer->pages),
GFP_KERNEL);
if (!helper_buffer->pages) {
ret = -ENOMEM;
goto free_cma;
}
for (pg = 0; pg < helper_buffer->pagecount; pg++)
helper_buffer->pages[pg] = &cma_pages[pg];
/* create the dmabuf */
dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
if (IS_ERR(dmabuf)) {
ret = PTR_ERR(dmabuf);
goto free_pages;
}
helper_buffer->dmabuf = dmabuf;
helper_buffer->priv_virt = cma_pages;
ret = dma_buf_fd(dmabuf, fd_flags);
if (ret < 0) {
dma_buf_put(dmabuf);
/* just return, as put will call release and that will free */
return ret;
}
return ret;
free_pages:
kfree(helper_buffer->pages);
free_cma:
cma_release(cma_heap->cma, cma_pages, nr_pages);
free_buf:
kfree(helper_buffer);
return ret;
}
static const struct dma_heap_ops cma_heap_ops = {
.allocate = cma_heap_allocate,
};
static int __add_cma_heap(struct cma *cma, void *data)
{
struct cma_heap *cma_heap;
struct dma_heap_export_info exp_info;
cma_heap = kzalloc(sizeof(*cma_heap), GFP_KERNEL);
if (!cma_heap)
return -ENOMEM;
cma_heap->cma = cma;
exp_info.name = cma_get_name(cma);
exp_info.ops = &cma_heap_ops;
exp_info.priv = cma_heap;
cma_heap->heap = dma_heap_add(&exp_info);
if (IS_ERR(cma_heap->heap)) {
int ret = PTR_ERR(cma_heap->heap);
kfree(cma_heap);
return ret;
}
return 0;
}
static int add_default_cma_heap(void)
{
struct cma *default_cma = dev_get_cma_area(NULL);
int ret = 0;
if (default_cma)
ret = __add_cma_heap(default_cma, NULL);
return ret;
}
module_init(add_default_cma_heap);
MODULE_DESCRIPTION("DMA-BUF CMA Heap");
MODULE_LICENSE("GPL v2");
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