path: root/kernel/dma/mapping.c

// SPDX-License-Identifier: GPL-2.0
/*
 * arch-independent dma-mapping routines
 *
 * Copyright (c) 2006  SUSE Linux Products GmbH
 * Copyright (c) 2006  Tejun Heo <teheo@suse.de>
 */
#include <linux/memblock.h> /* for max_pfn */
#include <linux/acpi.h>
#include <linux/dma-map-ops.h>
#include <linux/export.h>
#include <linux/gfp.h>
#include <linux/of_device.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include "debug.h"
#include "direct.h"

/*
 * Managed DMA API
 */
struct dma_devres {
	size_t		size;
	void		*vaddr;
	dma_addr_t	dma_handle;
	unsigned long	attrs;
};

static void dmam_release(struct device *dev, void *res)
{
	struct dma_devres *this = res;

	dma_free_attrs(dev, this->size, this->vaddr, this->dma_handle,
			this->attrs);
}

static int dmam_match(struct device *dev, void *res, void *match_data)
{
	struct dma_devres *this = res, *match = match_data;

	if (this->vaddr == match->vaddr) {
		WARN_ON(this->size != match->size ||
			this->dma_handle != match->dma_handle);
		return 1;
	}
	return 0;
}

/**
 * dmam_free_coherent - Managed dma_free_coherent()
 * @dev: Device to free coherent memory for
 * @size: Size of allocation
 * @vaddr: Virtual address of the memory to free
 * @dma_handle: DMA handle of the memory to free
 *
 * Managed dma_free_coherent().
 */
void dmam_free_coherent(struct device *dev, size_t size, void *vaddr,
			dma_addr_t dma_handle)
{
	struct dma_devres match_data = { size, vaddr, dma_handle };

	dma_free_coherent(dev, size, vaddr, dma_handle);
	WARN_ON(devres_destroy(dev, dmam_release, dmam_match, &match_data));
}
EXPORT_SYMBOL(dmam_free_coherent);

/**
 * dmam_alloc_attrs - Managed dma_alloc_attrs()
 * @dev: Device to allocate non_coherent memory for
 * @size: Size of allocation
 * @dma_handle: Out argument for allocated DMA handle
 * @gfp: Allocation flags
 * @attrs: Flags in the DMA_ATTR_* namespace.
 *
 * Managed dma_alloc_attrs().  Memory allocated using this function will be
 * automatically released on driver detach.
 *
 * RETURNS:
 * Pointer to allocated memory on success, NULL on failure.
 */
void *dmam_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
		gfp_t gfp, unsigned long attrs)
{
	struct dma_devres *dr;
	void *vaddr;

	dr = devres_alloc(dmam_release, sizeof(*dr), gfp);
	if (!dr)
		return NULL;

	vaddr = dma_alloc_attrs(dev, size, dma_handle, gfp, attrs);
	if (!vaddr) {
		devres_free(dr);
		return NULL;
	}

	dr->vaddr = vaddr;
	dr->dma_handle = *dma_handle;
	dr->size = size;
	dr->attrs = attrs;

	devres_add(dev, dr);

	return vaddr;
}
EXPORT_SYMBOL(dmam_alloc_attrs);

static bool dma_go_direct(struct device *dev, dma_addr_t mask,
		const struct dma_map_ops *ops)
{
	if (likely(!ops))
		return true;
#ifdef CONFIG_DMA_OPS_BYPASS
	if (dev->dma_ops_bypass)
		return min_not_zero(mask, dev->bus_dma_limit) >=
			    dma_direct_get_required_mask(dev);
#endif
	return false;
}


/*
 * Check if the devices uses a direct mapping for streaming DMA operations.
 * This allows IOMMU drivers to set a bypass mode if the DMA mask is large
 * enough.
 */
static inline bool dma_alloc_direct(struct device *dev,
		const struct dma_map_ops *ops)
{
	return dma_go_direct(dev, dev->coherent_dma_mask, ops);
}

static inline bool dma_map_direct(struct device *dev,
		const struct dma_map_ops *ops)
{
	return dma_go_direct(dev, *dev->dma_mask, ops);
}

dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page,
		size_t offset, size_t size, enum dma_data_direction dir,
		unsigned long attrs)
{
	const struct dma_map_ops *ops = get_dma_ops(dev);
	dma_addr_t addr;

	BUG_ON(!valid_dma_direction(dir));

	if (WARN_ON_ONCE(!dev->dma_mask))
		return DMA_MAPPING_ERROR;

	if (dma_map_direct(dev, ops) ||
	    arch_dma_map_page_direct(dev, page_to_phys(page) + offset + size))
		addr = dma_direct_map_page(dev, page, offset, size, dir, attrs);
	else
		addr = ops->map_page(dev, page, offset, size, dir, attrs);
	debug_dma_map_page(dev, page, offset, size, dir, addr);

	return addr;
}
EXPORT_SYMBOL(dma_map_page_attrs);

void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr, size_t size,
		enum dma_data_direction dir, unsigned long attrs)
{
	const struct dma_map_ops *ops = get_dma_ops(dev);

	BUG_ON(!valid_dma_direction(dir));
	if (dma_map_direct(dev, ops) ||
	    arch_dma_unmap_page_direct(dev, addr + size))
		dma_direct_unmap_page(dev, addr, size, dir, attrs);
	else if (ops->unmap_page)
		ops->unmap_page(dev, addr, size, dir, attrs);
	debug_dma_unmap_page(dev, addr, size, dir);
}
EXPORT_SYMBOL(dma_unmap_page_attrs);

/*
 * dma_maps_sg_attrs returns 0 on error and > 0 on success.
 * It should never return a value < 0.
 */
int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents,
		enum dma_data_direction dir, unsigned long attrs)
{
	const struct dma_map_ops *ops = get_dma_ops(dev);
	int ents;

	BUG_ON(!valid_dma_direction(dir));

	if (WARN_ON_ONCE(!dev->dma_mask))
		return 0;

	if (dma_map_direct(dev, ops) ||
	    arch_dma_map_sg_direct(dev, sg, nents))
		ents = dma_direct_map_sg(dev, sg, nents, dir, attrs);
	else
		ents = ops->map_sg(dev, sg, nents, dir, attrs);
	BUG_ON(ents < 0);
	debug_dma_map_sg(dev, sg, nents, ents, dir);

	return ents;
}
EXPORT_SYMBOL(dma_map_sg_attrs);

void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
				      int nents, enum dma_data_direction dir,
				      unsigned long attrs)
{
	const struct dma_map_ops *ops