6a5c7be5e4
The hook dma_get_required_mask is supposed to return the mask required by the platform to operate efficently. The generic version of dma_get_required_mask in driver/base/platform.c returns a mask based only on max_pfn. However, this is likely too big for iommu systems and could be too small for platforms that require a dma offset or have a secondary window at a high offset. Override the default, provide a hook in ppc_md used by pseries lpar and cell, and provide the default answer based on memblock_end_of_DRAM(), with hooks for get_dma_offset, and provide an implementation for iommu that looks at the defined table size. Coverting from the end address to the required bit mask is based on the generic implementation. The need for this was discovered when the qla2xxx driver switched to 64 bit dma then reverted to 32 bit when dma_get_required_mask said 32 bits was sufficient. Signed-off-by: Milton Miller <miltonm@bga.com> Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-kernel@vger.kernel.org Cc: benh@kernel.crashing.org Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
116 lines
3.4 KiB
C
116 lines
3.4 KiB
C
/*
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* Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
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*
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* Provide default implementations of the DMA mapping callbacks for
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* busses using the iommu infrastructure
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*/
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#include <asm/iommu.h>
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/*
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* Generic iommu implementation
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*/
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/* Allocates a contiguous real buffer and creates mappings over it.
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* Returns the virtual address of the buffer and sets dma_handle
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* to the dma address (mapping) of the first page.
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*/
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static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
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dma_addr_t *dma_handle, gfp_t flag)
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{
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return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
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dma_handle, dev->coherent_dma_mask, flag,
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dev_to_node(dev));
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}
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static void dma_iommu_free_coherent(struct device *dev, size_t size,
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void *vaddr, dma_addr_t dma_handle)
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{
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iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
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}
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/* Creates TCEs for a user provided buffer. The user buffer must be
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* contiguous real kernel storage (not vmalloc). The address passed here
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* comprises a page address and offset into that page. The dma_addr_t
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* returned will point to the same byte within the page as was passed in.
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*/
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static dma_addr_t dma_iommu_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 direction,
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struct dma_attrs *attrs)
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{
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return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
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size, device_to_mask(dev), direction, attrs);
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}
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static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
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size_t size, enum dma_data_direction direction,
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struct dma_attrs *attrs)
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{
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iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
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attrs);
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}
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static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
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int nelems, enum dma_data_direction direction,
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struct dma_attrs *attrs)
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{
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return iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
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device_to_mask(dev), direction, attrs);
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}
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static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
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int nelems, enum dma_data_direction direction,
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struct dma_attrs *attrs)
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{
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iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems, direction,
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attrs);
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}
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/* We support DMA to/from any memory page via the iommu */
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static int dma_iommu_dma_supported(struct device *dev, u64 mask)
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{
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struct iommu_table *tbl = get_iommu_table_base(dev);
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if (!tbl) {
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dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx"
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", table unavailable\n", mask);
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return 0;
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}
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if ((tbl->it_offset + tbl->it_size) > (mask >> IOMMU_PAGE_SHIFT)) {
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dev_info(dev, "Warning: IOMMU window too big for device mask\n");
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dev_info(dev, "mask: 0x%08llx, table end: 0x%08lx\n",
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mask, (tbl->it_offset + tbl->it_size) <<
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IOMMU_PAGE_SHIFT);
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return 0;
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} else
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return 1;
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}
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u64 dma_iommu_get_required_mask(struct device *dev)
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{
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struct iommu_table *tbl = get_iommu_table_base(dev);
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u64 mask;
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if (!tbl)
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return 0;
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mask = 1ULL < (fls_long(tbl->it_offset + tbl->it_size) - 1);
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mask += mask - 1;
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return mask;
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}
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struct dma_map_ops dma_iommu_ops = {
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.alloc_coherent = dma_iommu_alloc_coherent,
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.free_coherent = dma_iommu_free_coherent,
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.map_sg = dma_iommu_map_sg,
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.unmap_sg = dma_iommu_unmap_sg,
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.dma_supported = dma_iommu_dma_supported,
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.map_page = dma_iommu_map_page,
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.unmap_page = dma_iommu_unmap_page,
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};
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EXPORT_SYMBOL(dma_iommu_ops);
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