linux/kernel/dma/direct.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2018 Christoph Hellwig.
 *
 * DMA operations that map physical memory directly without using an IOMMU.
 */
#ifndef _KERNEL_DMA_DIRECT_H
#define _KERNEL_DMA_DIRECT_H

#include <linux/dma-direct.h>
#include <linux/memremap.h>

int dma_direct_get_sgtable(struct device *dev, struct sg_table *sgt,
		void *cpu_addr, dma_addr_t dma_addr, size_t size,
		unsigned long attrs);
bool dma_direct_can_mmap(struct device *dev);
int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma,
		void *cpu_addr, dma_addr_t dma_addr, size_t size,
		unsigned long attrs);
bool dma_direct_need_sync(struct device *dev, dma_addr_t dma_addr);
int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
		enum dma_data_direction dir, unsigned long attrs);
bool dma_direct_all_ram_mapped(struct device *dev);
size_t dma_direct_max_mapping_size(struct device *dev);

#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
    defined(CONFIG_SWIOTLB)
void dma_direct_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
		int nents, enum dma_data_direction dir);
#else
static inline void dma_direct_sync_sg_for_device(struct device *dev,
		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
{
}
#endif

#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
    defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) || \
    defined(CONFIG_SWIOTLB)
void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
		int nents, enum dma_data_direction dir, unsigned long attrs);
void dma_direct_sync_sg_for_cpu(struct device *dev,
		struct scatterlist *sgl, int nents, enum dma_data_direction dir);
#else
static inline void dma_direct_unmap_sg(struct device *dev,
		struct scatterlist *sgl, int nents, enum dma_data_direction dir,
		unsigned long attrs)
{
}
static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
{
}
#endif

static inline void dma_direct_sync_single_for_device(struct device *dev,
		dma_addr_t addr, size_t size, enum dma_data_direction dir)
{
	phys_addr_t paddr = dma_to_phys(dev, addr);

	swiotlb_sync_single_for_device(dev, paddr, size, dir);

	if (!dev_is_dma_coherent(dev)) {
		arch_sync_dma_for_device(paddr, size, dir);
		arch_sync_dma_flush();
	}
}

static inline void dma_direct_sync_single_for_cpu(struct device *dev,
		dma_addr_t addr, size_t size, enum dma_data_direction dir)
{
	phys_addr_t paddr = dma_to_phys(dev, addr);

	if (!dev_is_dma_coherent(dev)) {
		arch_sync_dma_for_cpu(paddr, size, dir);
		arch_sync_dma_flush();
		arch_sync_dma_for_cpu_all();
	}

	swiotlb_sync_single_for_cpu(dev, paddr, size, dir);
}

static inline dma_addr_t dma_direct_map_phys(struct device *dev,
		phys_addr_t phys, size_t size, enum dma_data_direction dir,
		unsigned long attrs)
{
	dma_addr_t dma_addr;

	if (is_swiotlb_force_bounce(dev)) {
		if (attrs & DMA_ATTR_MMIO)
			goto err_overflow;

		return swiotlb_map(dev, phys, size, dir, attrs);
	}

	if (attrs & DMA_ATTR_MMIO) {
		dma_addr = phys;
		if (unlikely(!dma_capable(dev, dma_addr, size, false)))
			goto err_overflow;
	} else {
		dma_addr = phys_to_dma(dev, phys);
		if (unlikely(!dma_capable(dev, dma_addr, size, true)) ||
		    dma_kmalloc_needs_bounce(dev, size, dir)) {
			if (is_swiotlb_active(dev))
				return swiotlb_map(dev, phys, size, dir, attrs);

			goto err_overflow;
		}
	}

	if (!dev_is_dma_coherent(dev) &&
	    !(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO))) {
		arch_sync_dma_for_device(phys, size, dir);
		arch_sync_dma_flush();
	}
	return dma_addr;

err_overflow:
	dev_WARN_ONCE(
		dev, 1,
		"DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n",
		&dma_addr, size, *dev->dma_mask, dev->bus_dma_limit);
	return DMA_MAPPING_ERROR;
}

static inline void dma_direct_unmap_phys(struct device *dev, dma_addr_t addr,
		size_t size, enum dma_data_direction dir, unsigned long attrs)
{
	phys_addr_t phys;

	if (attrs & DMA_ATTR_MMIO)
		/* nothing to do: uncached and no swiotlb */
		return;

	phys = dma_to_phys(dev, addr);
	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
		dma_direct_sync_single_for_cpu(dev, addr, size, dir);

	swiotlb_tbl_unmap_single(dev, phys, size, dir,
					 attrs | DMA_ATTR_SKIP_CPU_SYNC);
}
#endif /* _KERNEL_DMA_DIRECT_H */