diff options
Diffstat (limited to 'drivers/iommu')
| -rw-r--r-- | drivers/iommu/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/iommu/Makefile | 1 | ||||
| -rw-r--r-- | drivers/iommu/dma-iommu.c | 524 |
3 files changed, 532 insertions, 0 deletions
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index d9da766719c8..7414f33acfba 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -49,6 +49,13 @@ config OF_IOMMU def_bool y depends on OF && IOMMU_API +# IOMMU-agnostic DMA-mapping layer +config IOMMU_DMA + bool + depends on NEED_SG_DMA_LENGTH + select IOMMU_API + select IOMMU_IOVA + config FSL_PAMU bool "Freescale IOMMU support" depends on PPC32 diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile index c6dcc513d711..f465cfbdb183 100644 --- a/drivers/iommu/Makefile +++ b/drivers/iommu/Makefile @@ -1,6 +1,7 @@ obj-$(CONFIG_IOMMU_API) += iommu.o obj-$(CONFIG_IOMMU_API) += iommu-traces.o obj-$(CONFIG_IOMMU_API) += iommu-sysfs.o +obj-$(CONFIG_IOMMU_DMA) += dma-iommu.o obj-$(CONFIG_IOMMU_IO_PGTABLE) += io-pgtable.o obj-$(CONFIG_IOMMU_IO_PGTABLE_LPAE) += io-pgtable-arm.o obj-$(CONFIG_IOMMU_IOVA) += iova.o diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c new file mode 100644 index 000000000000..3a20db4f8604 --- /dev/null +++ b/drivers/iommu/dma-iommu.c @@ -0,0 +1,524 @@ +/* + * A fairly generic DMA-API to IOMMU-API glue layer. + * + * Copyright (C) 2014-2015 ARM Ltd. + * + * based in part on arch/arm/mm/dma-mapping.c: + * Copyright (C) 2000-2004 Russell King + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/device.h> +#include <linux/dma-iommu.h> +#include <linux/huge_mm.h> +#include <linux/iommu.h> +#include <linux/iova.h> +#include <linux/mm.h> + +int iommu_dma_init(void) +{ + return iova_cache_get(); +} + +/** + * iommu_get_dma_cookie - Acquire DMA-API resources for a domain + * @domain: IOMMU domain to prepare for DMA-API usage + * + * IOMMU drivers should normally call this from their domain_alloc + * callback when domain->type == IOMMU_DOMAIN_DMA. + */ +int iommu_get_dma_cookie(struct iommu_domain *domain) +{ + struct iova_domain *iovad; + + if (domain->iova_cookie) + return -EEXIST; + + iovad = kzalloc(sizeof(*iovad), GFP_KERNEL); + domain->iova_cookie = iovad; + + return iovad ? 0 : -ENOMEM; +} +EXPORT_SYMBOL(iommu_get_dma_cookie); + +/** + * iommu_put_dma_cookie - Release a domain's DMA mapping resources + * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie() + * + * IOMMU drivers should normally call this from their domain_free callback. + */ +void iommu_put_dma_cookie(struct iommu_domain *domain) +{ + struct iova_domain *iovad = domain->iova_cookie; + + if (!iovad) + return; + + put_iova_domain(iovad); + kfree(iovad); + domain->iova_cookie = NULL; +} +EXPORT_SYMBOL(iommu_put_dma_cookie); + +/** + * iommu_dma_init_domain - Initialise a DMA mapping domain + * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie() + * @base: IOVA at which the mappable address space starts + * @size: Size of IOVA space + * + * @base and @size should be exact multiples of IOMMU page granularity to + * avoid rounding surprises. If necessary, we reserve the page at address 0 + * to ensure it is an invalid IOVA. It is safe to reinitialise a domain, but + * any change which could make prior IOVAs invalid will fail. + */ +int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size) +{ + struct iova_domain *iovad = domain->iova_cookie; + unsigned long order, base_pfn, end_pfn; + + if (!iovad) + return -ENODEV; + + /* Use the smallest supported page size for IOVA granularity */ + order = __ffs(domain->ops->pgsize_bitmap); + base_pfn = max_t(unsigned long, 1, base >> order); + end_pfn = (base + size - 1) >> order; + + /* Check the domain allows at least some access to the device... */ + if (domain->geometry.force_aperture) { + if (base > domain->geometry.aperture_end || + base + size <= domain->geometry.aperture_start) { + pr_warn("specified DMA range outside IOMMU capability\n"); + return -EFAULT; + } + /* ...then finally give it a kicking to make sure it fits */ + base_pfn = max_t(unsigned long, base_pfn, + domain->geometry.aperture_start >> order); + end_pfn = min_t(unsigned long, end_pfn, + domain->geometry.aperture_end >> order); + } + + /* All we can safely do with an existing domain is enlarge it */ + if (iovad->start_pfn) { + if (1UL << order != iovad->granule || + base_pfn != iovad->start_pfn || + end_pfn < iovad->dma_32bit_pfn) { + pr_warn("Incompatible range for DMA domain\n"); + return -EFAULT; + } + iovad->dma_32bit_pfn = end_pfn; + } else { + init_iova_domain(iovad, 1UL << order, base_pfn, end_pfn); + } + return 0; +} +EXPORT_SYMBOL(iommu_dma_init_domain); + +/** + * dma_direction_to_prot - Translate DMA API directions to IOMMU API page flags + * @dir: Direction of DMA transfer + * @coherent: Is the DMA master cache-coherent? + * + * Return: corresponding IOMMU API page protection flags + */ +int dma_direction_to_prot(enum dma_data_direction dir, bool coherent) +{ + int prot = coherent ? IOMMU_CACHE : 0; + + switch (dir) { + case DMA_BIDIRECTIONAL: + return prot | IOMMU_READ | IOMMU_WRITE; + case DMA_TO_DEVICE: + return prot | IOMMU_READ; + case DMA_FROM_DEVICE: + return prot | IOMMU_WRITE; + default: + return 0; + } +} + +static struct iova *__alloc_iova(struct iova_domain *iovad, size_t size, + dma_addr_t dma_limit) +{ + unsigned long shift = iova_shift(iovad); + unsigned long length = iova_align(iovad, size) >> shift; + + /* + * Enforce size-alignment to be safe - there could perhaps be an + * attribute to control this per-device, or at least per-domain... + */ + return alloc_iova(iovad, length, dma_limit >> shift, true); +} + +/* The IOVA allocator knows what we mapped, so just unmap whatever that was */ +static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t dma_addr) +{ + struct iova_domain *iovad = domain->iova_cookie; + unsigned long shift = iova_shift(iovad); + unsigned long pfn = dma_addr >> shift; + struct iova *iova = find_iova(iovad, pfn); + size_t size; + + if (WARN_ON(!iova)) + return; + + size = iova_size(iova) << shift; + size -= iommu_unmap(domain, pfn << shift, size); + /* ...and if we can't, then something is horribly, horribly wrong */ + WARN_ON(size > 0); + __free_iova(iovad, iova); +} + +static void __iommu_dma_free_pages(struct page **pages, int count) +{ + while (count--) + __free_page(pages[count]); + kvfree(pages); +} + +static struct page **__iommu_dma_alloc_pages(unsigned int count, gfp_t gfp) +{ + struct page **pages; + unsigned int i = 0, array_size = count * sizeof(*pages); + + if (array_size <= PAGE_SIZE) + pages = kzalloc(array_size, GFP_KERNEL); + else + pages = vzalloc(array_size); + if (!pages) + return NULL; + + /* IOMMU can map any pages, so himem can also be used here */ + gfp |= __GFP_NOWARN | __GFP_HIGHMEM; + + while (count) { + struct page *page = NULL; + int j, order = __fls(count); + + /* + * Higher-order allocations are a convenience rather + * than a necessity, hence using __GFP_NORETRY until + * falling back to single-page allocations. + */ + for (order = min(order, MAX_ORDER); order > 0; order--) { + page = alloc_pages(gfp | __GFP_NORETRY, order); + if (!page) + continue; + if (PageCompound(page)) { + if (!split_huge_page(page)) + break; + __free_pages(page, order); + } else { + split_page(page, order); + break; + } + } + if (!page) + page = alloc_page(gfp); + if (!page) { + __iommu_dma_free_pages(pages, i); + return NULL; + } + j = 1 << order; + count -= j; + while (j--) + pages[i++] = page++; + } + return pages; +} + +/** + * iommu_dma_free - Free a buffer allocated by iommu_dma_alloc() + * @dev: Device which owns this buffer + * @pages: Array of buffer pages as returned by iommu_dma_alloc() + * @size: Size of buffer in bytes + * @handle: DMA address of buffer + * + * Frees both the pages associated with the buffer, and the array + * describing them + */ +void iommu_dma_free(struct device *dev, struct page **pages, size_t size, + dma_addr_t *handle) +{ + __iommu_dma_unmap(iommu_get_domain_for_dev(dev), *handle); + __iommu_dma_free_pages(pages, PAGE_ALIGN(size) >> PAGE_SHIFT); + *handle = DMA_ERROR_CODE; +} + +/** + * iommu_dma_alloc - Allocate and map a buffer contiguous in IOVA space + * @dev: Device to allocate memory for. Must be a real device + * attached to an iommu_dma_domain + * @size: Size of buffer in bytes + * @gfp: Allocation flags + * @prot: IOMMU mapping flags + * @handle: Out argument for allocated DMA handle + * @flush_page: Arch callback which must ensure PAGE_SIZE bytes from the + * given VA/PA are visible to the given non-coherent device. + * + * If @size is less than PAGE_SIZE, then a full CPU page will be allocated, + * but an IOMMU which supports smaller pages might not map the whole thing. + * + * Return: Array of struct page pointers describing the buffer, + * or NULL on failure. + */ +struct page **iommu_dma_alloc(struct device *dev, size_t size, + gfp_t gfp, int prot, dma_addr_t *handle, + void (*flush_page)(struct device *, const void *, phys_addr_t)) +{ + struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + struct iova_domain *iovad = domain->iova_cookie; + struct iova *iova; + struct page **pages; + struct sg_table sgt; + dma_addr_t dma_addr; + unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; + + *handle = DMA_ERROR_CODE; + + pages = __iommu_dma_alloc_pages(count, gfp); + if (!pages) + return NULL; + + iova = __alloc_iova(iovad, size, dev->coherent_dma_mask); + if (!iova) + goto out_free_pages; + + size = iova_align(iovad, size); + if (sg_alloc_table_from_pages(&sgt, pages, count, 0, size, GFP_KERNEL)) + goto out_free_iova; + + if (!(prot & IOMMU_CACHE)) { + struct sg_mapping_iter miter; + /* + * The CPU-centric flushing implied by SG_MITER_TO_SG isn't + * sufficient here, so skip it by using the "wrong" direction. + */ + sg_miter_start(&miter, sgt.sgl, sgt.orig_nents, SG_MITER_FROM_SG); + while (sg_miter_next(&miter)) + flush_page(dev, miter.addr, page_to_phys(miter.page)); + sg_miter_stop(&miter); + } + + dma_addr = iova_dma_addr(iovad, iova); + if (iommu_map_sg(domain, dma_addr, sgt.sgl, sgt.orig_nents, prot) + < size) + goto out_free_sg; + + *handle = dma_addr; + sg_free_table(&sgt); + return pages; + +out_free_sg: + sg_free_table(&sgt); +out_free_iova: + __free_iova(iovad, iova); +out_free_pages: + __iommu_dma_free_pages(pages, count); + return NULL; +} + +/** + * iommu_dma_mmap - Map a buffer into provided user VMA + * @pages: Array representing buffer from iommu_dma_alloc() + * @size: Size of buffer in bytes + * @vma: VMA describing requested userspace mapping + * + * Maps the pages of the buffer in @pages into @vma. The caller is responsible + * for verifying the correct size and protection of @vma beforehand. + */ + +int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma) +{ + unsigned long uaddr = vma->vm_start; + unsigned int i, count = PAGE_ALIGN(size) >> PAGE_SHIFT; + int ret = -ENXIO; + + for (i = vma->vm_pgoff; i < count && uaddr < vma->vm_end; i++) { + ret = vm_insert_page(vma, uaddr, pages[i]); + if (ret) + break; + uaddr += PAGE_SIZE; + } + return ret; +} + +dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page, + unsigned long offset, size_t size, int prot) +{ + dma_addr_t dma_addr; + struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + struct iova_domain *iovad = domain->iova_cookie; + phys_addr_t phys = page_to_phys(page) + offset; + size_t iova_off = iova_offset(iovad, phys); + size_t len = iova_align(iovad, size + iova_off); + struct iova *iova = __alloc_iova(iovad, len, dma_get_mask(dev)); + + if (!iova) + return DMA_ERROR_CODE; + + dma_addr = iova_dma_addr(iovad, iova); + if (iommu_map(domain, dma_addr, phys - iova_off, len, prot)) { + __free_iova(iovad, iova); + return DMA_ERROR_CODE; + } + return dma_addr + iova_off; +} + +void iommu_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size, + enum dma_data_direction dir, struct dma_attrs *attrs) +{ + __iommu_dma_unmap(iommu_get_domain_for_dev(dev), handle); +} + +/* + * Prepare a successfully-mapped scatterlist to give back to the caller. + * Handling IOVA concatenation can come later, if needed + */ +static int __finalise_sg(struct device *dev, struct scatterlist *sg, int nents, + dma_addr_t dma_addr) +{ + struct scatterlist *s; + int i; + + for_each_sg(sg, s, nents, i) { + /* Un-swizzling the fields here, hence the naming mismatch */ + unsigned int s_offset = sg_dma_address(s); + unsigned int s_length = sg_dma_len(s); + unsigned int s_dma_len = s->length; + + s->offset = s_offset; + s->length = s_length; + sg_dma_address(s) = dma_addr + s_offset; + dma_addr += s_dma_len; + } + return i; +} + +/* + * If mapping failed, then just restore the original list, + * but making sure the DMA fields are invalidated. + */ +static void __invalidate_sg(struct scatterlist *sg, int nents) +{ + struct scatterlist *s; + int i; + + for_each_sg(sg, s, nents, i) { + if (sg_dma_address(s) != DMA_ERROR_CODE) + s->offset = sg_dma_address(s); + if (sg_dma_len(s)) + s->length = sg_dma_len(s); + sg_dma_address(s) = DMA_ERROR_CODE; + sg_dma_len(s) = 0; + } +} + +/* + * The DMA API client is passing in a scatterlist which could describe + * any old buffer layout, but the IOMMU API requires everything to be + * aligned to IOMMU pages. Hence the need for this complicated bit of + * impedance-matching, to be able to hand off a suitably-aligned list, + * but still preserve the original offsets and sizes for the caller. + */ +int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, + int nents, int prot) +{ + struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + struct iova_domain *iovad = domain->iova_cookie; + struct iova *iova; + struct scatterlist *s, *prev = NULL; + dma_addr_t dma_addr; + size_t iova_len = 0; + int i; + + /* + * Work out how much IOVA space we need, and align the segments to + * IOVA granules for the IOMMU driver to handle. With some clever + * trickery we can modify the list in-place, but reversibly, by + * hiding the original data in the as-yet-unused DMA fields. + */ + for_each_sg(sg, s, nents, i) { + size_t s_offset = iova_offset(iovad, s->offset); + size_t s_length = s->length; + + sg_dma_address(s) = s->offset; + sg_dma_len(s) = s_length; + s->offset -= s_offset; + s_length = iova_align(iovad, s_length + s_offset); + s->length = s_length; + + /* + * The simple way to avoid the rare case of a segment + * crossing the boundary mask is to pad the previous one + * to end at a naturally-aligned IOVA for this one's size, + * at the cost of potentially over-allocating a little. + */ + if (prev) { + size_t pad_len = roundup_pow_of_two(s_length); + + pad_len = (pad_len - iova_len) & (pad_len - 1); + prev->length += pad_len; + iova_len += pad_len; + } + + iova_len += s_length; + prev = s; + } + + iova = __alloc_iova(iovad, iova_len, dma_get_mask(dev)); + if (!iova) + goto out_restore_sg; + + /* + * We'll leave any physical concatenation to the IOMMU driver's + * implementation - it knows better than we do. + */ + dma_addr = iova_dma_addr(iovad, iova); + if (iommu_map_sg(domain, dma_addr, sg, nents, prot) < iova_len) + goto out_free_iova; + + return __finalise_sg(dev, sg, nents, dma_addr); + +out_free_iova: + __free_iova(iovad, iova); +out_restore_sg: + __invalidate_sg(sg, nents); + return 0; +} + +void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, + enum dma_data_direction dir, struct dma_attrs *attrs) +{ + /* + * The scatterlist segments are mapped into a single + * contiguous IOVA allocation, so this is incredibly easy. + */ + __iommu_dma_unmap(iommu_get_domain_for_dev(dev), sg_dma_address(sg)); +} + +int iommu_dma_supported(struct device *dev, u64 mask) +{ + /* + * 'Special' IOMMUs which don't have the same addressing capability + * as the CPU will have to wait until we have some way to query that + * before they'll be able to use this framework. + */ + return 1; +} + +int iommu_dma_mapping_error(struct device *dev, dma_addr_t dma_addr) +{ + return dma_addr == DMA_ERROR_CODE; +} |