Commit 4ad4c1f3 authored by Robin Murphy's avatar Robin Murphy Committed by Christoph Hellwig
Browse files

dma-mapping: don't store redundant offsets 



A bus_dma_region necessarily stores both CPU and DMA base addresses for
a range, so there's no need to also store the difference between them.

Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Acked-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 3f716859

drivers/acpi/scan.c

+0 −1
Original line number Diff line number Diff line
@@ -1532,7 +1532,6 @@ int acpi_dma_get_range(struct device *dev, const struct bus_dma_region **map) 
			r->cpu_start = rentry->res->start;

			r->dma_start = rentry->res->start - rentry->offset;

			r->size = resource_size(rentry->res);

			r->offset = rentry->offset;

			r++;

		}

	}

drivers/of/address.c

+0 −1
Original line number Diff line number Diff line
@@ -955,7 +955,6 @@ int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map) 
		r->cpu_start = range.cpu_addr;

		r->dma_start = range.bus_addr;

		r->size = range.size;

		r->offset = range.cpu_addr - range.bus_addr;

		r++;

	}

out:

include/linux/dma-direct.h

+12 −7
Original line number Diff line number Diff line
@@ -21,7 +21,6 @@ struct bus_dma_region { 
	phys_addr_t	cpu_start;

	dma_addr_t	dma_start;

	u64		size;

	u64		offset;

};



static inline dma_addr_t translate_phys_to_dma(struct device *dev,
@@ -29,9 +28,12 @@ static inline dma_addr_t translate_phys_to_dma(struct device *dev, 
{

	const struct bus_dma_region *m;



	for (m = dev->dma_range_map; m->size; m++)

		if (paddr >= m->cpu_start && paddr - m->cpu_start < m->size)

			return (dma_addr_t)paddr - m->offset;

	for (m = dev->dma_range_map; m->size; m++) {

		u64 offset = paddr - m->cpu_start;



		if (paddr >= m->cpu_start && offset < m->size)

			return m->dma_start + offset;

	}



	/* make sure dma_capable fails when no translation is available */

	return DMA_MAPPING_ERROR;
@@ -42,9 +44,12 @@ static inline phys_addr_t translate_dma_to_phys(struct device *dev, 
{

	const struct bus_dma_region *m;



	for (m = dev->dma_range_map; m->size; m++)

		if (dma_addr >= m->dma_start && dma_addr - m->dma_start < m->size)

			return (phys_addr_t)dma_addr + m->offset;

	for (m = dev->dma_range_map; m->size; m++) {

		u64 offset = dma_addr - m->dma_start;



		if (dma_addr >= m->dma_start && offset < m->size)

			return m->cpu_start + offset;

	}



	return (phys_addr_t)-1;

}

kernel/dma/direct.c

+0 −1
Original line number Diff line number Diff line
@@ -677,7 +677,6 @@ int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start, 
		return -ENOMEM;

	map[0].cpu_start = cpu_start;

	map[0].dma_start = dma_start;

	map[0].offset = offset;

	map[0].size = size;

	dev->dma_range_map = map;

	return 0;