forked from Minki/linux
52 lines
1.4 KiB
C
52 lines
1.4 KiB
C
|
// SPDX-License-Identifier: GPL-2.0
|
||
|
/*
|
||
|
* Helpers for DMA ops implementations. These generally rely on the fact that
|
||
|
* the allocated memory contains normal pages in the direct kernel mapping.
|
||
|
*/
|
||
|
#include <linux/dma-noncoherent.h>
|
||
|
|
||
|
/*
|
||
|
* Create scatter-list for the already allocated DMA buffer.
|
||
|
*/
|
||
|
int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
|
||
|
void *cpu_addr, dma_addr_t dma_addr, size_t size,
|
||
|
unsigned long attrs)
|
||
|
{
|
||
|
struct page *page = virt_to_page(cpu_addr);
|
||
|
int ret;
|
||
|
|
||
|
ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
|
||
|
if (!ret)
|
||
|
sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Create userspace mapping for the DMA-coherent memory.
|
||
|
*/
|
||
|
int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
|
||
|
void *cpu_addr, dma_addr_t dma_addr, size_t size,
|
||
|
unsigned long attrs)
|
||
|
{
|
||
|
#ifdef CONFIG_MMU
|
||
|
unsigned long user_count = vma_pages(vma);
|
||
|
unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
|
||
|
unsigned long off = vma->vm_pgoff;
|
||
|
int ret = -ENXIO;
|
||
|
|
||
|
vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
|
||
|
|
||
|
if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
|
||
|
return ret;
|
||
|
|
||
|
if (off >= count || user_count > count - off)
|
||
|
return -ENXIO;
|
||
|
|
||
|
return remap_pfn_range(vma, vma->vm_start,
|
||
|
page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff,
|
||
|
user_count << PAGE_SHIFT, vma->vm_page_prot);
|
||
|
#else
|
||
|
return -ENXIO;
|
||
|
#endif /* CONFIG_MMU */
|
||
|
}
|