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// 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-map-ops.h>
#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 */
}
struct page *dma_common_alloc_pages(struct device *dev, size_t size,
dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
struct page *page;
page = dma_alloc_contiguous(dev, size, gfp);
if (!page)
page = alloc_pages_node(dev_to_node(dev), gfp, get_order(size));
if (!page)
return NULL;
*dma_handle = ops->map_page(dev, page, 0, size, dir,
DMA_ATTR_SKIP_CPU_SYNC);
if (*dma_handle == DMA_MAPPING_ERROR) {
dma_free_contiguous(dev, page, size);
return NULL;
}
memset(page_address(page), 0, size);
return page;
}
void dma_common_free_pages(struct device *dev, size_t size, struct page *page,
dma_addr_t dma_handle, enum dma_data_direction dir)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
if (ops->unmap_page)
ops->unmap_page(dev, dma_handle, size, dir,
DMA_ATTR_SKIP_CPU_SYNC);
dma_free_contiguous(dev, page, size);
}
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