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- /*
- * DMA mapping support for platforms lacking IOMMUs.
- *
- * Copyright (C) 2009 Paul Mundt
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- */
- #include <linux/dma-mapping.h>
- #include <linux/io.h>
- static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
- unsigned long offset, size_t size,
- enum dma_data_direction dir,
- unsigned long attrs)
- {
- dma_addr_t addr = page_to_phys(page) + offset;
- WARN_ON(size == 0);
- dma_cache_sync(dev, page_address(page) + offset, size, dir);
- return addr;
- }
- static int nommu_map_sg(struct device *dev, struct scatterlist *sg,
- int nents, enum dma_data_direction dir,
- unsigned long attrs)
- {
- struct scatterlist *s;
- int i;
- WARN_ON(nents == 0 || sg[0].length == 0);
- for_each_sg(sg, s, nents, i) {
- BUG_ON(!sg_page(s));
- dma_cache_sync(dev, sg_virt(s), s->length, dir);
- s->dma_address = sg_phys(s);
- s->dma_length = s->length;
- }
- return nents;
- }
- #ifdef CONFIG_DMA_NONCOHERENT
- static void nommu_sync_single(struct device *dev, dma_addr_t addr,
- size_t size, enum dma_data_direction dir)
- {
- dma_cache_sync(dev, phys_to_virt(addr), size, dir);
- }
- static void nommu_sync_sg(struct device *dev, struct scatterlist *sg,
- int nelems, enum dma_data_direction dir)
- {
- struct scatterlist *s;
- int i;
- for_each_sg(sg, s, nelems, i)
- dma_cache_sync(dev, sg_virt(s), s->length, dir);
- }
- #endif
- struct dma_map_ops nommu_dma_ops = {
- .alloc = dma_generic_alloc_coherent,
- .free = dma_generic_free_coherent,
- .map_page = nommu_map_page,
- .map_sg = nommu_map_sg,
- #ifdef CONFIG_DMA_NONCOHERENT
- .sync_single_for_device = nommu_sync_single,
- .sync_sg_for_device = nommu_sync_sg,
- #endif
- .is_phys = 1,
- };
- void __init no_iommu_init(void)
- {
- if (dma_ops)
- return;
- dma_ops = &nommu_dma_ops;
- }
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