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Diffstat (limited to '')
| -rw-r--r-- | arch/powerpc/kernel/dma-iommu.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/dma-iommu.c b/arch/powerpc/kernel/dma-iommu.c new file mode 100644 index 000000000..9ac065179 --- /dev/null +++ b/arch/powerpc/kernel/dma-iommu.c @@ -0,0 +1,152 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation + * + * Provide default implementations of the DMA mapping callbacks for + * busses using the iommu infrastructure + */ + +#include <linux/dma-direct.h> +#include <linux/pci.h> +#include <asm/iommu.h> + +/* + * Generic iommu implementation + */ + +/* 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, + unsigned long attrs) +{ + return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size, + dma_handle, dev->coherent_dma_mask, flag, + dev_to_node(dev)); +} + +static void dma_iommu_free_coherent(struct device *dev, size_t size, + void *vaddr, dma_addr_t dma_handle, + unsigned long attrs) +{ + iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle); +} + +/* Creates TCEs for a user provided buffer. The user buffer must be + * contiguous real kernel storage (not vmalloc). The address passed here + * comprises a page address and offset into that page. The dma_addr_t + * returned will point to the same byte within the page as was passed in. + */ +static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page, + unsigned long offset, size_t size, + enum dma_data_direction direction, + unsigned long attrs) +{ + return iommu_map_page(dev, get_iommu_table_base(dev), page, offset, + size, dma_get_mask(dev), direction, attrs); +} + + +static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle, + size_t size, enum dma_data_direction direction, + unsigned long attrs) +{ + iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction, + attrs); +} + + +static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist, + int nelems, enum dma_data_direction direction, + unsigned long attrs) +{ + return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems, + dma_get_mask(dev), direction, attrs); +} + +static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist, + int nelems, enum dma_data_direction direction, + unsigned long attrs) +{ + ppc_iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems, + direction, attrs); +} + +static bool dma_iommu_bypass_supported(struct device *dev, u64 mask) +{ + struct pci_dev *pdev = to_pci_dev(dev); + struct pci_controller *phb = pci_bus_to_host(pdev->bus); + + if (iommu_fixed_is_weak || !phb->controller_ops.iommu_bypass_supported) + return false; + return phb->controller_ops.iommu_bypass_supported(pdev, mask); +} + +/* We support DMA to/from any memory page via the iommu */ +int dma_iommu_dma_supported(struct device *dev, u64 mask) +{ + struct iommu_table *tbl = get_iommu_table_base(dev); + + if (dev_is_pci(dev) && dma_iommu_bypass_supported(dev, mask)) { + dev->dma_ops_bypass = true; + dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n"); + return 1; + } + + if (!tbl) { + dev_err(dev, "Warning: IOMMU dma not supported: mask 0x%08llx, table unavailable\n", mask); + return 0; + } + + if (tbl->it_offset > (mask >> tbl->it_page_shift)) { + dev_info(dev, "Warning: IOMMU offset too big for device mask\n"); + dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n", + mask, tbl->it_offset << tbl->it_page_shift); + return 0; + } + + dev_dbg(dev, "iommu: not 64-bit, using default ops\n"); + dev->dma_ops_bypass = false; + return 1; +} + +u64 dma_iommu_get_required_mask(struct device *dev) +{ + struct iommu_table *tbl = get_iommu_table_base(dev); + u64 mask; + + if (dev_is_pci(dev)) { + u64 bypass_mask = dma_direct_get_required_mask(dev); + + if (dma_iommu_dma_supported(dev, bypass_mask)) { + dev_info(dev, "%s: returning bypass mask 0x%llx\n", __func__, bypass_mask); + return bypass_mask; + } + } + + if (!tbl) + return 0; + + mask = 1ULL << (fls_long(tbl->it_offset + tbl->it_size) + + tbl->it_page_shift - 1); + mask += mask - 1; + + return mask; +} + +const struct dma_map_ops dma_iommu_ops = { + .alloc = dma_iommu_alloc_coherent, + .free = dma_iommu_free_coherent, + .map_sg = dma_iommu_map_sg, + .unmap_sg = dma_iommu_unmap_sg, + .dma_supported = dma_iommu_dma_supported, + .map_page = dma_iommu_map_page, + .unmap_page = dma_iommu_unmap_page, + .get_required_mask = dma_iommu_get_required_mask, + .mmap = dma_common_mmap, + .get_sgtable = dma_common_get_sgtable, + .alloc_pages = dma_common_alloc_pages, + .free_pages = dma_common_free_pages, +}; |