linux/kernel/dma/ops_helpers.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-map-ops.h>

static struct page *dma_common_vaddr_to_page(void *cpu_addr)
{ … }

/*
 * 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)
{ … }

/*
 * 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)
{ … }

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)
{ … }

void dma_common_free_pages(struct device *dev, size_t size, struct page *page,
		dma_addr_t dma_handle, enum dma_data_direction dir)
{ … }