/* * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation * * Provide default implementations of the DMA mapping callbacks for * directly mapped busses and busses using the iommu infrastructure */ #include <linux/device.h> #include <linux/dma-mapping.h> #include <asm/bug.h> #include <asm/iommu.h> #include <asm/abs_addr.h> /* * Generic iommu implementation */ static inline unsigned long device_to_mask(struct device *dev) { if (dev->dma_mask && *dev->dma_mask) return *dev->dma_mask; /* Assume devices without mask can take 32 bit addresses */ return 0xfffffffful; } /* Allocates a contiguous real buffer and creates mappings over it. * Returns the virtual address of the buffer and sets dma_handle * to the dma address (mapping) of the first page. */ static void *dma_iommu_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t flag) { return iommu_alloc_coherent(dev->archdata.dma_data, size, dma_handle, device_to_mask(dev), flag, dev->archdata.numa_node); } static void dma_iommu_free_coherent(struct device *dev, size_t size, void *vaddr, dma_addr_t dma_handle) { iommu_free_coherent(dev->archdata.dma_data, size, vaddr, dma_handle); } /* Creates TCEs for a user provided buffer. The user buffer must be * contiguous real kernel storage (not vmalloc). The address of the buffer * passed here is the kernel (virtual) address of the buffer. The buffer * need not be page aligned, the dma_addr_t returned will point to the same * byte within the page as vaddr. */ static dma_addr_t dma_iommu_map_single(struct device *dev, void *vaddr, size_t size, enum dma_data_direction direction) { return iommu_map_single(dev->archdata.dma_data, vaddr, size, device_to_mask(dev), direction); } static void dma_iommu_unmap_single(struct device *dev, dma_addr_t dma_handle, size_t size, enum dma_data_direction direction) { iommu_unmap_single(dev->archdata.dma_data, dma_handle, size, direction); } static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist, int nelems, enum dma_data_direction direction) { return iommu_map_sg(dev->archdata.dma_data, sglist, nelems, device_to_mask(dev), direction); } static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist, int nelems, enum dma_data_direction direction) { iommu_unmap_sg(dev->archdata.dma_data, sglist, nelems, direction); } /* We support DMA to/from any memory page via the iommu */ static int dma_iommu_dma_supported(struct device *dev, u64 mask) { struct iommu_table *tbl = dev->archdata.dma_data; if (!tbl || tbl->it_offset > mask) { printk(KERN_INFO "Warning: IOMMU offset too big for device mask\n"); if (tbl) printk(KERN_INFO "mask: 0x%08lx, table offset: 0x%08lx\n", mask, tbl->it_offset); else printk(KERN_INFO "mask: 0x%08lx, table unavailable\n", mask); return 0; } else return 1; } struct dma_mapping_ops dma_iommu_ops = { .alloc_coherent = dma_iommu_alloc_coherent, .free_coherent = dma_iommu_free_coherent, .map_single = dma_iommu_map_single, .unmap_single = dma_iommu_unmap_single, .map_sg = dma_iommu_map_sg, .unmap_sg = dma_iommu_unmap_sg, .dma_supported = dma_iommu_dma_supported, }; EXPORT_SYMBOL(dma_iommu_ops); /* * Generic direct DMA implementation * * This implementation supports a global offset that can be applied if * the address at which memory is visible to devices is not 0. */ unsigned long dma_direct_offset; static void *dma_direct_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t flag) { struct page *page; void *ret; int node = dev->archdata.numa_node; /* TODO: Maybe use the numa node here too ? */ page = alloc_pages_node(node, flag, get_order(size)); if (page == NULL) return NULL; ret = page_address(page); memset(ret, 0, size); *dma_handle = virt_to_abs(ret) | dma_direct_offset; return ret; } static void dma_direct_free_coherent(struct device *dev, size_t size, void *vaddr, dma_addr_t dma_handle) { free_pages((unsigned long)vaddr, get_order(size)); } static dma_addr_t dma_direct_map_single(struct device *dev, void *ptr, size_t size, enum dma_data_direction direction) { return virt_to_abs(ptr) | dma_direct_offset; } static void dma_direct_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size, enum dma_data_direction direction) { } static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents, enum dma_data_direction direction) { struct scatterlist *sg; int i; for_each_sg(sgl, sg, nents, i) { sg->dma_address = sg_phys(sg) | dma_direct_offset; sg->dma_length = sg->length; } return nents; } static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction direction) { } static int dma_direct_dma_supported(struct device *dev, u64 mask) { /* Could be improved to check for memory though it better be * done via some global so platforms can set the limit in case * they have limited DMA windows */ return mask >= DMA_32BIT_MASK; } struct dma_mapping_ops dma_direct_ops = { .alloc_coherent = dma_direct_alloc_coherent, .free_coherent = dma_direct_free_coherent, .map_single = dma_direct_map_single, .unmap_single = dma_direct_unmap_single, .map_sg = dma_direct_map_sg, .unmap_sg = dma_direct_unmap_sg, .dma_supported = dma_direct_dma_supported, }; EXPORT_SYMBOL(dma_direct_ops);