forked from luck/tmp_suning_uos_patched
325ef1857f
This was used by the ide, scsi and networking code in the past to determine if they should bounce payloads. Now that the dma mapping always have to support dma to all physical memory (thanks to swiotlb for non-iommu systems) there is no need to this crude hack any more. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Palmer Dabbelt <palmer@sifive.com> (for riscv) Reviewed-by: Jens Axboe <axboe@kernel.dk>
89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
/*
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* DMA mapping support for platforms lacking IOMMUs.
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*
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* Copyright (C) 2009 Paul Mundt
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/dma-mapping.h>
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#include <linux/io.h>
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#include <asm/cacheflush.h>
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static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
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unsigned long offset, size_t size,
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enum dma_data_direction dir,
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unsigned long attrs)
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{
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dma_addr_t addr = page_to_phys(page) + offset
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- PFN_PHYS(dev->dma_pfn_offset);
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WARN_ON(size == 0);
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if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
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sh_sync_dma_for_device(page_address(page) + offset, size, dir);
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return addr;
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}
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static int nommu_map_sg(struct device *dev, struct scatterlist *sg,
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int nents, enum dma_data_direction dir,
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unsigned long attrs)
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{
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struct scatterlist *s;
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int i;
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WARN_ON(nents == 0 || sg[0].length == 0);
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for_each_sg(sg, s, nents, i) {
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dma_addr_t offset = PFN_PHYS(dev->dma_pfn_offset);
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BUG_ON(!sg_page(s));
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if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
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sh_sync_dma_for_device(sg_virt(s), s->length, dir);
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s->dma_address = sg_phys(s) - offset;
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s->dma_length = s->length;
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}
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return nents;
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}
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#ifdef CONFIG_DMA_NONCOHERENT
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static void nommu_sync_single_for_device(struct device *dev, dma_addr_t addr,
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size_t size, enum dma_data_direction dir)
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{
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sh_sync_dma_for_device(phys_to_virt(addr), size, dir);
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}
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static void nommu_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
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int nelems, enum dma_data_direction dir)
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{
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struct scatterlist *s;
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int i;
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for_each_sg(sg, s, nelems, i)
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sh_sync_dma_for_device(sg_virt(s), s->length, dir);
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}
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#endif
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const struct dma_map_ops nommu_dma_ops = {
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.alloc = dma_generic_alloc_coherent,
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.free = dma_generic_free_coherent,
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.map_page = nommu_map_page,
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.map_sg = nommu_map_sg,
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#ifdef CONFIG_DMA_NONCOHERENT
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.sync_single_for_device = nommu_sync_single_for_device,
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.sync_sg_for_device = nommu_sync_sg_for_device,
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#endif
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};
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void __init no_iommu_init(void)
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{
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if (dma_ops)
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return;
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dma_ops = &nommu_dma_ops;
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}
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