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Diffstat (limited to 'drivers/iommu/dma-iommu.c')
| -rw-r--r-- | drivers/iommu/dma-iommu.c | 1288 |
1 files changed, 1288 insertions, 0 deletions
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c new file mode 100644 index 000000000..d1539b739 --- /dev/null +++ b/drivers/iommu/dma-iommu.c @@ -0,0 +1,1288 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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 + */ + +#include <linux/acpi_iort.h> +#include <linux/device.h> +#include <linux/dma-map-ops.h> +#include <linux/dma-iommu.h> +#include <linux/gfp.h> +#include <linux/huge_mm.h> +#include <linux/iommu.h> +#include <linux/iova.h> +#include <linux/irq.h> +#include <linux/mm.h> +#include <linux/mutex.h> +#include <linux/pci.h> +#include <linux/scatterlist.h> +#include <linux/vmalloc.h> +#include <linux/crash_dump.h> + +struct iommu_dma_msi_page { + struct list_head list; + dma_addr_t iova; + phys_addr_t phys; +}; + +enum iommu_dma_cookie_type { + IOMMU_DMA_IOVA_COOKIE, + IOMMU_DMA_MSI_COOKIE, +}; + +struct iommu_dma_cookie { + enum iommu_dma_cookie_type type; + union { + /* Full allocator for IOMMU_DMA_IOVA_COOKIE */ + struct iova_domain iovad; + /* Trivial linear page allocator for IOMMU_DMA_MSI_COOKIE */ + dma_addr_t msi_iova; + }; + struct list_head msi_page_list; + + /* Domain for flush queue callback; NULL if flush queue not in use */ + struct iommu_domain *fq_domain; +}; + +static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie) +{ + if (cookie->type == IOMMU_DMA_IOVA_COOKIE) + return cookie->iovad.granule; + return PAGE_SIZE; +} + +static struct iommu_dma_cookie *cookie_alloc(enum iommu_dma_cookie_type type) +{ + struct iommu_dma_cookie *cookie; + + cookie = kzalloc(sizeof(*cookie), GFP_KERNEL); + if (cookie) { + INIT_LIST_HEAD(&cookie->msi_page_list); + cookie->type = type; + } + return cookie; +} + +/** + * 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) +{ + if (domain->iova_cookie) + return -EEXIST; + + domain->iova_cookie = cookie_alloc(IOMMU_DMA_IOVA_COOKIE); + if (!domain->iova_cookie) + return -ENOMEM; + + return 0; +} +EXPORT_SYMBOL(iommu_get_dma_cookie); + +/** + * iommu_get_msi_cookie - Acquire just MSI remapping resources + * @domain: IOMMU domain to prepare + * @base: Start address of IOVA region for MSI mappings + * + * Users who manage their own IOVA allocation and do not want DMA API support, + * but would still like to take advantage of automatic MSI remapping, can use + * this to initialise their own domain appropriately. Users should reserve a + * contiguous IOVA region, starting at @base, large enough to accommodate the + * number of PAGE_SIZE mappings necessary to cover every MSI doorbell address + * used by the devices attached to @domain. + */ +int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base) +{ + struct iommu_dma_cookie *cookie; + + if (domain->type != IOMMU_DOMAIN_UNMANAGED) + return -EINVAL; + + if (domain->iova_cookie) + return -EEXIST; + + cookie = cookie_alloc(IOMMU_DMA_MSI_COOKIE); + if (!cookie) + return -ENOMEM; + + cookie->msi_iova = base; + domain->iova_cookie = cookie; + return 0; +} +EXPORT_SYMBOL(iommu_get_msi_cookie); + +/** + * iommu_put_dma_cookie - Release a domain's DMA mapping resources + * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie() or + * iommu_get_msi_cookie() + * + * IOMMU drivers should normally call this from their domain_free callback. + */ +void iommu_put_dma_cookie(struct iommu_domain *domain) +{ + struct iommu_dma_cookie *cookie = domain->iova_cookie; + struct iommu_dma_msi_page *msi, *tmp; + + if (!cookie) + return; + + if (cookie->type == IOMMU_DMA_IOVA_COOKIE && cookie->iovad.granule) + put_iova_domain(&cookie->iovad); + + list_for_each_entry_safe(msi, tmp, &cookie->msi_page_list, list) { + list_del(&msi->list); + kfree(msi); + } + kfree(cookie); + domain->iova_cookie = NULL; +} +EXPORT_SYMBOL(iommu_put_dma_cookie); + +/** + * iommu_dma_get_resv_regions - Reserved region driver helper + * @dev: Device from iommu_get_resv_regions() + * @list: Reserved region list from iommu_get_resv_regions() + * + * IOMMU drivers can use this to implement their .get_resv_regions callback + * for general non-IOMMU-specific reservations. Currently, this covers GICv3 + * ITS region reservation on ACPI based ARM platforms that may require HW MSI + * reservation. + */ +void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list) +{ + + if (!is_of_node(dev_iommu_fwspec_get(dev)->iommu_fwnode)) + iort_iommu_msi_get_resv_regions(dev, list); + +} +EXPORT_SYMBOL(iommu_dma_get_resv_regions); + +static int cookie_init_hw_msi_region(struct iommu_dma_cookie *cookie, + phys_addr_t start, phys_addr_t end) +{ + struct iova_domain *iovad = &cookie->iovad; + struct iommu_dma_msi_page *msi_page; + int i, num_pages; + + start -= iova_offset(iovad, start); + num_pages = iova_align(iovad, end - start) >> iova_shift(iovad); + + for (i = 0; i < num_pages; i++) { + msi_page = kmalloc(sizeof(*msi_page), GFP_KERNEL); + if (!msi_page) + return -ENOMEM; + + msi_page->phys = start; + msi_page->iova = start; + INIT_LIST_HEAD(&msi_page->list); + list_add(&msi_page->list, &cookie->msi_page_list); + start += iovad->granule; + } + + return 0; +} + +static int iova_reserve_pci_windows(struct pci_dev *dev, + struct iova_domain *iovad) +{ + struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus); + struct resource_entry *window; + unsigned long lo, hi; + phys_addr_t start = 0, end; + + resource_list_for_each_entry(window, &bridge->windows) { + if (resource_type(window->res) != IORESOURCE_MEM) + continue; + + lo = iova_pfn(iovad, window->res->start - window->offset); + hi = iova_pfn(iovad, window->res->end - window->offset); + reserve_iova(iovad, lo, hi); + } + + /* Get reserved DMA windows from host bridge */ + resource_list_for_each_entry(window, &bridge->dma_ranges) { + end = window->res->start - window->offset; +resv_iova: + if (end > start) { + lo = iova_pfn(iovad, start); + hi = iova_pfn(iovad, end); + reserve_iova(iovad, lo, hi); + } else if (end < start) { + /* dma_ranges list should be sorted */ + dev_err(&dev->dev, + "Failed to reserve IOVA [%pa-%pa]\n", + &start, &end); + return -EINVAL; + } + + start = window->res->end - window->offset + 1; + /* If window is last entry */ + if (window->node.next == &bridge->dma_ranges && + end != ~(phys_addr_t)0) { + end = ~(phys_addr_t)0; + goto resv_iova; + } + } + + return 0; +} + +static int iova_reserve_iommu_regions(struct device *dev, + struct iommu_domain *domain) +{ + struct iommu_dma_cookie *cookie = domain->iova_cookie; + struct iova_domain *iovad = &cookie->iovad; + struct iommu_resv_region *region; + LIST_HEAD(resv_regions); + int ret = 0; + + if (dev_is_pci(dev)) { + ret = iova_reserve_pci_windows(to_pci_dev(dev), iovad); + if (ret) + return ret; + } + + iommu_get_resv_regions(dev, &resv_regions); + list_for_each_entry(region, &resv_regions, list) { + unsigned long lo, hi; + + /* We ARE the software that manages these! */ + if (region->type == IOMMU_RESV_SW_MSI) + continue; + + lo = iova_pfn(iovad, region->start); + hi = iova_pfn(iovad, region->start + region->length - 1); + reserve_iova(iovad, lo, hi); + + if (region->type == IOMMU_RESV_MSI) + ret = cookie_init_hw_msi_region(cookie, region->start, + region->start + region->length); + if (ret) + break; + } + iommu_put_resv_regions(dev, &resv_regions); + + return ret; +} + +static void iommu_dma_flush_iotlb_all(struct iova_domain *iovad) +{ + struct iommu_dma_cookie *cookie; + struct iommu_domain *domain; + + cookie = container_of(iovad, struct iommu_dma_cookie, iovad); + domain = cookie->fq_domain; + /* + * The IOMMU driver supporting DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE + * implies that ops->flush_iotlb_all must be non-NULL. + */ + domain->ops->flush_iotlb_all(domain); +} + +/** + * 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 + * @dev: Device the domain is being initialised for + * + * @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. + */ +static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, + u64 size, struct device *dev) +{ + struct iommu_dma_cookie *cookie = domain->iova_cookie; + unsigned long order, base_pfn; + struct iova_domain *iovad; + int attr; + + if (!cookie || cookie->type != IOMMU_DMA_IOVA_COOKIE) + return -EINVAL; + + iovad = &cookie->iovad; + + /* Use the smallest supported page size for IOVA granularity */ + order = __ffs(domain->pgsize_bitmap); + base_pfn = max_t(unsigned long, 1, base >> 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); + } + + /* start_pfn is always nonzero for an already-initialised domain */ + if (iovad->start_pfn) { + if (1UL << order != iovad->granule || + base_pfn != iovad->start_pfn) { + pr_warn("Incompatible range for DMA domain\n"); + return -EFAULT; + } + + return 0; + } + + init_iova_domain(iovad, 1UL << order, base_pfn); + + if (!cookie->fq_domain && !iommu_domain_get_attr(domain, + DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, &attr) && attr) { + if (init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all, + NULL)) + pr_warn("iova flush queue initialization failed\n"); + else + cookie->fq_domain = domain; + } + + if (!dev) + return 0; + + return iova_reserve_iommu_regions(dev, domain); +} + +static int iommu_dma_deferred_attach(struct device *dev, + struct iommu_domain *domain) +{ + const struct iommu_ops *ops = domain->ops; + + if (!is_kdump_kernel()) + return 0; + + if (unlikely(ops->is_attach_deferred && + ops->is_attach_deferred(domain, dev))) + return iommu_attach_device(domain, dev); + + return 0; +} + +/** + * dma_info_to_prot - Translate DMA API directions and attributes to IOMMU API + * page flags. + * @dir: Direction of DMA transfer + * @coherent: Is the DMA master cache-coherent? + * @attrs: DMA attributes for the mapping + * + * Return: corresponding IOMMU API page protection flags + */ +static int dma_info_to_prot(enum dma_data_direction dir, bool coherent, + unsigned long attrs) +{ + int prot = coherent ? IOMMU_CACHE : 0; + + if (attrs & DMA_ATTR_PRIVILEGED) + prot |= IOMMU_PRIV; + + 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 dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain, + size_t size, u64 dma_limit, struct device *dev) +{ + struct iommu_dma_cookie *cookie = domain->iova_cookie; + struct iova_domain *iovad = &cookie->iovad; + unsigned long shift, iova_len, iova = 0; + + if (cookie->type == IOMMU_DMA_MSI_COOKIE) { + cookie->msi_iova += size; + return cookie->msi_iova - size; + } + + shift = iova_shift(iovad); + iova_len = size >> shift; + /* + * Freeing non-power-of-two-sized allocations back into the IOVA caches + * will come back to bite us badly, so we have to waste a bit of space + * rounding up anything cacheable to make sure that can't happen. The + * order of the unadjusted size will still match upon freeing. + */ + if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1))) + iova_len = roundup_pow_of_two(iova_len); + + dma_limit = min_not_zero(dma_limit, dev->bus_dma_limit); + + if (domain->geometry.force_aperture) + dma_limit = min(dma_limit, (u64)domain->geometry.aperture_end); + + /* Try to get PCI devices a SAC address */ + if (dma_limit > DMA_BIT_MASK(32) && dev_is_pci(dev)) + iova = alloc_iova_fast(iovad, iova_len, + DMA_BIT_MASK(32) >> shift, false); + + if (!iova) + iova = alloc_iova_fast(iovad, iova_len, dma_limit >> shift, + true); + + return (dma_addr_t)iova << shift; +} + +static void iommu_dma_free_iova(struct iommu_dma_cookie *cookie, + dma_addr_t iova, size_t size) +{ + struct iova_domain *iovad = &cookie->iovad; + + /* The MSI case is only ever cleaning up its most recent allocation */ + if (cookie->type == IOMMU_DMA_MSI_COOKIE) + cookie->msi_iova -= size; + else if (cookie->fq_domain) /* non-strict mode */ + queue_iova(iovad, iova_pfn(iovad, iova), + size >> iova_shift(iovad), 0); + else + free_iova_fast(iovad, iova_pfn(iovad, iova), + size >> iova_shift(iovad)); +} + +static void __iommu_dma_unmap(struct device *dev, dma_addr_t dma_addr, + size_t size) +{ + struct iommu_domain *domain = iommu_get_dma_domain(dev); + struct iommu_dma_cookie *cookie = domain->iova_cookie; + struct iova_domain *iovad = &cookie->iovad; + size_t iova_off = iova_offset(iovad, dma_addr); + struct iommu_iotlb_gather iotlb_gather; + size_t unmapped; + + dma_addr -= iova_off; + size = iova_align(iovad, size + iova_off); + iommu_iotlb_gather_init(&iotlb_gather); + + unmapped = iommu_unmap_fast(domain, dma_addr, size, &iotlb_gather); + WARN_ON(unmapped != size); + + if (!cookie->fq_domain) + iommu_iotlb_sync(domain, &iotlb_gather); + iommu_dma_free_iova(cookie, dma_addr, size); +} + +static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys, + size_t size, int prot, u64 dma_mask) +{ + struct iommu_domain *domain = iommu_get_dma_domain(dev); + struct iommu_dma_cookie *cookie = domain->iova_cookie; + struct iova_domain *iovad = &cookie->iovad; + size_t iova_off = iova_offset(iovad, phys); + dma_addr_t iova; + + if (unlikely(iommu_dma_deferred_attach(dev, domain))) + return DMA_MAPPING_ERROR; + + size = iova_align(iovad, size + iova_off); + + iova = iommu_dma_alloc_iova(domain, size, dma_mask, dev); + if (!iova) + return DMA_MAPPING_ERROR; + + if (iommu_map_atomic(domain, iova, phys - iova_off, size, prot)) { + iommu_dma_free_iova(cookie, iova, size); + return DMA_MAPPING_ERROR; + } + return iova + iova_off; +} + +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(struct device *dev, + unsigned int count, unsigned long order_mask, gfp_t gfp) +{ + struct page **pages; + unsigned int i = 0, nid = dev_to_node(dev); + + order_mask &= (2U << MAX_ORDER) - 1; + if (!order_mask) + return NULL; + + pages = kvzalloc(count * sizeof(*pages), GFP_KERNEL); + if (!pages) + return NULL; + + /* IOMMU can map any pages, so himem can also be used here */ + gfp |= __GFP_NOWARN | __GFP_HIGHMEM; + + /* It makes no sense to muck about with huge pages */ + gfp &= ~__GFP_COMP; + + while (count) { + struct page *page = NULL; + unsigned int order_size; + + /* + * Higher-order allocations are a convenience rather + * than a necessity, hence using __GFP_NORETRY until + * falling back to minimum-order allocations. + */ + for (order_mask &= (2U << __fls(count)) - 1; + order_mask; order_mask &= ~order_size) { + unsigned int order = __fls(order_mask); + gfp_t alloc_flags = gfp; + + order_size = 1U << order; + if (order_mask > order_size) + alloc_flags |= __GFP_NORETRY; + page = alloc_pages_node(nid, alloc_flags, order); + if (!page) + continue; + if (order) + split_page(page, order); + break; + } + if (!page) { + __iommu_dma_free_pages(pages, i); + return NULL; + } + count -= order_size; + while (order_size--) + pages[i++] = page++; + } + return pages; +} + +/** + * iommu_dma_alloc_remap - 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 + * @dma_handle: Out argument for allocated DMA handle + * @gfp: Allocation flags + * @prot: pgprot_t to use for the remapped mapping + * @attrs: DMA attributes for this allocation + * + * 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: Mapped virtual address, or NULL on failure. + */ +static void *iommu_dma_alloc_remap(struct device *dev, size_t size, + dma_addr_t *dma_handle, gfp_t gfp, pgprot_t prot, + unsigned long attrs) +{ + struct iommu_domain *domain = iommu_get_dma_domain(dev); + struct iommu_dma_cookie *cookie = domain->iova_cookie; + struct iova_domain *iovad = &cookie->iovad; + bool coherent = dev_is_dma_coherent(dev); + int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs); + unsigned int count, min_size, alloc_sizes = domain->pgsize_bitmap; + struct page **pages; + struct sg_table sgt; + dma_addr_t iova; + void *vaddr; + + *dma_handle = DMA_MAPPING_ERROR; + + if (unlikely(iommu_dma_deferred_attach(dev, domain))) + return NULL; + + min_size = alloc_sizes & -alloc_sizes; + if (min_size < PAGE_SIZE) { + min_size = PAGE_SIZE; + alloc_sizes |= PAGE_SIZE; + } else { + size = ALIGN(size, min_size); + } + if (attrs & DMA_ATTR_ALLOC_SINGLE_PAGES) + alloc_sizes = min_size; + + count = PAGE_ALIGN(size) >> PAGE_SHIFT; + pages = __iommu_dma_alloc_pages(dev, count, alloc_sizes >> PAGE_SHIFT, + gfp); + if (!pages) + return NULL; + + size = iova_align(iovad, size); + iova = iommu_dma_alloc_iova(domain, size, dev->coherent_dma_mask, dev); + if (!iova) + goto out_free_pages; + + if (sg_alloc_table_from_pages(&sgt, pages, count, 0, size, GFP_KERNEL)) + goto out_free_iova; + + if (!(ioprot & IOMMU_CACHE)) { + struct scatterlist *sg; + int i; + + for_each_sg(sgt.sgl, sg, sgt.orig_nents, i) + arch_dma_prep_coherent(sg_page(sg), sg->length); + } + + if (iommu_map_sg_atomic(domain, iova, sgt.sgl, sgt.orig_nents, ioprot) + < size) + goto out_free_sg; + + vaddr = dma_common_pages_remap(pages, size, prot, + __builtin_return_address(0)); + if (!vaddr) + goto out_unmap; + + *dma_handle = iova; + sg_free_table(&sgt); + return vaddr; + +out_unmap: + __iommu_dma_unmap(dev, iova, size); +out_free_sg: + sg_free_table(&sgt); +out_free_iova: + iommu_dma_free_iova(cookie, iova, size); +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. + */ +static int __iommu_dma_mmap(struct page **pages, size_t size, + struct vm_area_struct *vma) +{ + return vm_map_pages(vma, pages, PAGE_ALIGN(size) >> PAGE_SHIFT); +} + +static void iommu_dma_sync_single_for_cpu(struct device *dev, + dma_addr_t dma_handle, size_t size, enum dma_data_direction dir) +{ + phys_addr_t phys; + + if (dev_is_dma_coherent(dev)) + return; + + phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle); + arch_sync_dma_for_cpu(phys, size, dir); +} + +static void iommu_dma_sync_single_for_device(struct device *dev, + dma_addr_t dma_handle, size_t size, enum dma_data_direction dir) +{ + phys_addr_t phys; + + if (dev_is_dma_coherent(dev)) + return; + + phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle); + arch_sync_dma_for_device(phys, size, dir); +} + +static void iommu_dma_sync_sg_for_cpu(struct device *dev, + struct scatterlist *sgl, int nelems, + enum dma_data_direction dir) +{ + struct scatterlist *sg; + int i; + + if (dev_is_dma_coherent(dev)) + return; + + for_each_sg(sgl, sg, nelems, i) + arch_sync_dma_for_cpu(sg_phys(sg), sg->length, dir); +} + +static void iommu_dma_sync_sg_for_device(struct device *dev, + struct scatterlist *sgl, int nelems, + enum dma_data_direction dir) +{ + struct scatterlist *sg; + int i; + + if (dev_is_dma_coherent(dev)) + return; + + for_each_sg(sgl, sg, nelems, i) + arch_sync_dma_for_device(sg_phys(sg), sg->length, dir); +} + +static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page, + unsigned long offset, size_t size, enum dma_data_direction dir, + unsigned long attrs) +{ + phys_addr_t phys = page_to_phys(page) + offset; + bool coherent = dev_is_dma_coherent(dev); + int prot = dma_info_to_prot(dir, coherent, attrs); + dma_addr_t dma_handle; + + dma_handle = __iommu_dma_map(dev, phys, size, prot, dma_get_mask(dev)); + if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC) && + dma_handle != DMA_MAPPING_ERROR) + arch_sync_dma_for_device(phys, size, dir); + return dma_handle; +} + +static void iommu_dma_unmap_page(struct device *dev, dma_addr_t dma_handle, + size_t size, enum dma_data_direction dir, unsigned long attrs) +{ + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + iommu_dma_sync_single_for_cpu(dev, dma_handle, size, dir); + __iommu_dma_unmap(dev, dma_handle, size); +} + +/* + * Prepare a successfully-mapped scatterlist to give back to the caller. + * + * At this point the segments are already laid out by iommu_dma_map_sg() to + * avoid individually crossing any boundaries, so we merely need to check a + * segment's start address to avoid concatenating across one. + */ +static int __finalise_sg(struct device *dev, struct scatterlist *sg, int nents, + dma_addr_t dma_addr) +{ + struct scatterlist *s, *cur = sg; + unsigned long seg_mask = dma_get_seg_boundary(dev); + unsigned int cur_len = 0, max_len = dma_get_max_seg_size(dev); + int i, count = 0; + + for_each_sg(sg, s, nents, i) { + /* Restore this segment's original unaligned fields first */ + unsigned int s_iova_off = sg_dma_address(s); + unsigned int s_length = sg_dma_len(s); + unsigned int s_iova_len = s->length; + + s->offset += s_iova_off; + s->length = s_length; + sg_dma_address(s) = DMA_MAPPING_ERROR; + sg_dma_len(s) = 0; + + /* + * Now fill in the real DMA data. If... + * - there is a valid output segment to append to + * - and this segment starts on an IOVA page boundary + * - but doesn't fall at a segment boundary + * - and wouldn't make the resulting output segment too long + */ + if (cur_len && !s_iova_off && (dma_addr & seg_mask) && + (max_len - cur_len >= s_length)) { + /* ...then concatenate it with the previous one */ + cur_len += s_length; + } else { + /* Otherwise start the next output segment */ + if (i > 0) + cur = sg_next(cur); + cur_len = s_length; + count++; + + sg_dma_address(cur) = dma_addr + s_iova_off; + } + + sg_dma_len(cur) = cur_len; + dma_addr += s_iova_len; + + if (s_length + s_iova_off < s_iova_len) + cur_len = 0; + } + return count; +} + +/* + * 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_MAPPING_ERROR) + s->offset += sg_dma_address(s); + if (sg_dma_len(s)) + s->length = sg_dma_len(s); + sg_dma_address(s) = DMA_MAPPING_ERROR; + 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. + */ +static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, + int nents, enum dma_data_direction dir, unsigned long attrs) +{ + struct iommu_domain *domain = iommu_get_dma_domain(dev); + struct iommu_dma_cookie *cookie = domain->iova_cookie; + struct iova_domain *iovad = &cookie->iovad; + struct scatterlist *s, *prev = NULL; + int prot = dma_info_to_prot(dir, dev_is_dma_coherent(dev), attrs); + dma_addr_t iova; + size_t iova_len = 0; + unsigned long mask = dma_get_seg_boundary(dev); + int i; + + if (unlikely(iommu_dma_deferred_attach(dev, domain))) + return 0; + + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + iommu_dma_sync_sg_for_device(dev, sg, nents, dir); + + /* + * 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 + * stashing the unaligned parts in the as-yet-unused DMA fields. + */ + for_each_sg(sg, s, nents, i) { + size_t s_iova_off = iova_offset(iovad, s->offset); + size_t s_length = s->length; + size_t pad_len = (mask - iova_len + 1) & mask; + + sg_dma_address(s) = s_iova_off; + sg_dma_len(s) = s_length; + s->offset -= s_iova_off; + s_length = iova_align(iovad, s_length + s_iova_off); + s->length = s_length; + + /* + * Due to the alignment of our single IOVA allocation, we can + * depend on these assumptions about the segment boundary mask: + * - If mask size >= IOVA size, then the IOVA range cannot + * possibly fall across a boundary, so we don't care. + * - If mask size < IOVA size, then the IOVA range must start + * exactly on a boundary, therefore we can lay things out + * based purely on segment lengths without needing to know + * the actual addresses beforehand. + * - The mask must be a power of 2, so pad_len == 0 if + * iova_len == 0, thus we cannot dereference prev the first + * time through here (i.e. before it has a meaningful value). + */ + if (pad_len && pad_len < s_length - 1) { + prev->length += pad_len; + iova_len += pad_len; + } + + iova_len += s_length; + prev = s; + } + + iova = iommu_dma_alloc_iova(domain, iova_len, dma_get_mask(dev), 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. + */ + if (iommu_map_sg_atomic(domain, iova, sg, nents, prot) < iova_len) + goto out_free_iova; + + return __finalise_sg(dev, sg, nents, iova); + +out_free_iova: + iommu_dma_free_iova(cookie, iova, iova_len); +out_restore_sg: + __invalidate_sg(sg, nents); + return 0; +} + +static void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, + int nents, enum dma_data_direction dir, unsigned long attrs) +{ + dma_addr_t start, end; + struct scatterlist *tmp; + int i; + + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + iommu_dma_sync_sg_for_cpu(dev, sg, nents, dir); + + /* + * The scatterlist segments are mapped into a single + * contiguous IOVA allocation, so this is incredibly easy. + */ + start = sg_dma_address(sg); + for_each_sg(sg_next(sg), tmp, nents - 1, i) { + if (sg_dma_len(tmp) == 0) + break; + sg = tmp; + } + end = sg_dma_address(sg) + sg_dma_len(sg); + __iommu_dma_unmap(dev, start, end - start); +} + +static dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys, + size_t size, enum dma_data_direction dir, unsigned long attrs) +{ + return __iommu_dma_map(dev, phys, size, + dma_info_to_prot(dir, false, attrs) | IOMMU_MMIO, + dma_get_mask(dev)); +} + +static void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle, + size_t size, enum dma_data_direction dir, unsigned long attrs) +{ + __iommu_dma_unmap(dev, handle, size); +} + +static void __iommu_dma_free(struct device *dev, size_t size, void *cpu_addr) +{ + size_t alloc_size = PAGE_ALIGN(size); + int count = alloc_size >> PAGE_SHIFT; + struct page *page = NULL, **pages = NULL; + + /* Non-coherent atomic allocation? Easy */ + if (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && + dma_free_from_pool(dev, cpu_addr, alloc_size)) + return; + + if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) { + /* + * If it the address is remapped, then it's either non-coherent + * or highmem CMA, or an iommu_dma_alloc_remap() construction. + */ + pages = dma_common_find_pages(cpu_addr); + if (!pages) + page = vmalloc_to_page(cpu_addr); + dma_common_free_remap(cpu_addr, alloc_size); + } else { + /* Lowmem means a coherent atomic or CMA allocation */ + page = virt_to_page(cpu_addr); + } + + if (pages) + __iommu_dma_free_pages(pages, count); + if (page) + dma_free_contiguous(dev, page, alloc_size); +} + +static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr, + dma_addr_t handle, unsigned long attrs) +{ + __iommu_dma_unmap(dev, handle, size); + __iommu_dma_free(dev, size, cpu_addr); +} + +static void *iommu_dma_alloc_pages(struct device *dev, size_t size, + struct page **pagep, gfp_t gfp, unsigned long attrs) +{ + bool coherent = dev_is_dma_coherent(dev); + size_t alloc_size = PAGE_ALIGN(size); + int node = dev_to_node(dev); + struct page *page = NULL; + void *cpu_addr; + + page = dma_alloc_contiguous(dev, alloc_size, gfp); + if (!page) + page = alloc_pages_node(node, gfp, get_order(alloc_size)); + if (!page) + return NULL; + + if (IS_ENABLED(CONFIG_DMA_REMAP) && (!coherent || PageHighMem(page))) { + pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs); + + cpu_addr = dma_common_contiguous_remap(page, alloc_size, + prot, __builtin_return_address(0)); + if (!cpu_addr) + goto out_free_pages; + + if (!coherent) + arch_dma_prep_coherent(page, size); + } else { + cpu_addr = page_address(page); + } + + *pagep = page; + memset(cpu_addr, 0, alloc_size); + return cpu_addr; +out_free_pages: + dma_free_contiguous(dev, page, alloc_size); + return NULL; +} + +static void *iommu_dma_alloc(struct device *dev, size_t size, + dma_addr_t *handle, gfp_t gfp, unsigned long attrs) +{ + bool coherent = dev_is_dma_coherent(dev); + int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs); + struct page *page = NULL; + void *cpu_addr; + + gfp |= __GFP_ZERO; + + if (IS_ENABLED(CONFIG_DMA_REMAP) && gfpflags_allow_blocking(gfp) && + !(attrs & DMA_ATTR_FORCE_CONTIGUOUS)) { + return iommu_dma_alloc_remap(dev, size, handle, gfp, + dma_pgprot(dev, PAGE_KERNEL, attrs), attrs); + } + + if (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && + !gfpflags_allow_blocking(gfp) && !coherent) + page = dma_alloc_from_pool(dev, PAGE_ALIGN(size), &cpu_addr, + gfp, NULL); + else + cpu_addr = iommu_dma_alloc_pages(dev, size, &page, gfp, attrs); + if (!cpu_addr) + return NULL; + + *handle = __iommu_dma_map(dev, page_to_phys(page), size, ioprot, + dev->coherent_dma_mask); + if (*handle == DMA_MAPPING_ERROR) { + __iommu_dma_free(dev, size, cpu_addr); + return NULL; + } + + return cpu_addr; +} + +#ifdef CONFIG_DMA_REMAP +static void *iommu_dma_alloc_noncoherent(struct device *dev, size_t size, + dma_addr_t *handle, enum dma_data_direction dir, gfp_t gfp) +{ + if (!gfpflags_allow_blocking(gfp)) { + struct page *page; + + page = dma_common_alloc_pages(dev, size, handle, dir, gfp); + if (!page) + return NULL; + return page_address(page); + } + + return iommu_dma_alloc_remap(dev, size, handle, gfp | __GFP_ZERO, + PAGE_KERNEL, 0); +} + +static void iommu_dma_free_noncoherent(struct device *dev, size_t size, + void *cpu_addr, dma_addr_t handle, enum dma_data_direction dir) +{ + __iommu_dma_unmap(dev, handle, size); + __iommu_dma_free(dev, size, cpu_addr); +} +#else +#define iommu_dma_alloc_noncoherent NULL +#define iommu_dma_free_noncoherent NULL +#endif /* CONFIG_DMA_REMAP */ + +static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma, + void *cpu_addr, dma_addr_t dma_addr, size_t size, + unsigned long attrs) +{ + unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; + unsigned long pfn, off = vma->vm_pgoff; + int ret; + + vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs); + + if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret)) + return ret; + + if (off >= nr_pages || vma_pages(vma) > nr_pages - off) + return -ENXIO; + + if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) { + struct page **pages = dma_common_find_pages(cpu_addr); + + if (pages) + return __iommu_dma_mmap(pages, size, vma); + pfn = vmalloc_to_pfn(cpu_addr); + } else { + pfn = page_to_pfn(virt_to_page(cpu_addr)); + } + + return remap_pfn_range(vma, vma->vm_start, pfn + off, + vma->vm_end - vma->vm_start, + vma->vm_page_prot); +} + +static int iommu_dma_get_sgtable(struct device *dev, struct sg_table *sgt, + void *cpu_addr, dma_addr_t dma_addr, size_t size, + unsigned long attrs) +{ + struct page *page; + int ret; + + if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) { + struct page **pages = dma_common_find_pages(cpu_addr); + + if (pages) { + return sg_alloc_table_from_pages(sgt, pages, + PAGE_ALIGN(size) >> PAGE_SHIFT, + 0, size, GFP_KERNEL); + } + + page = vmalloc_to_page(cpu_addr); + } else { + page = virt_to_page(cpu_addr); + } + + ret = sg_alloc_table(sgt, 1, GFP_KERNEL); + if (!ret) + sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0); + return ret; +} + +static unsigned long iommu_dma_get_merge_boundary(struct device *dev) +{ + struct iommu_domain *domain = iommu_get_dma_domain(dev); + + return (1UL << __ffs(domain->pgsize_bitmap)) - 1; +} + +static const struct dma_map_ops iommu_dma_ops = { + .alloc = iommu_dma_alloc, + .free = iommu_dma_free, + .alloc_pages = dma_common_alloc_pages, + .free_pages = dma_common_free_pages, + .alloc_noncoherent = iommu_dma_alloc_noncoherent, + .free_noncoherent = iommu_dma_free_noncoherent, + .mmap = iommu_dma_mmap, + .get_sgtable = iommu_dma_get_sgtable, + .map_page = iommu_dma_map_page, + .unmap_page = iommu_dma_unmap_page, + .map_sg = iommu_dma_map_sg, + .unmap_sg = iommu_dma_unmap_sg, + .sync_single_for_cpu = iommu_dma_sync_single_for_cpu, + .sync_single_for_device = iommu_dma_sync_single_for_device, + .sync_sg_for_cpu = iommu_dma_sync_sg_for_cpu, + .sync_sg_for_device = iommu_dma_sync_sg_for_device, + .map_resource = iommu_dma_map_resource, + .unmap_resource = iommu_dma_unmap_resource, + .get_merge_boundary = iommu_dma_get_merge_boundary, +}; + +/* + * The IOMMU core code allocates the default DMA domain, which the underlying + * IOMMU driver needs to support via the dma-iommu layer. + */ +void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size) +{ + struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + + if (!domain) + goto out_err; + + /* + * The IOMMU core code allocates the default DMA domain, which the + * underlying IOMMU driver needs to support via the dma-iommu layer. + */ + if (domain->type == IOMMU_DOMAIN_DMA) { + if (iommu_dma_init_domain(domain, dma_base, size, dev)) + goto out_err; + dev->dma_ops = &iommu_dma_ops; + } + + return; +out_err: + pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n", + dev_name(dev)); +} + +static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev, + phys_addr_t msi_addr, struct iommu_domain *domain) +{ + struct iommu_dma_cookie *cookie = domain->iova_cookie; + struct iommu_dma_msi_page *msi_page; + dma_addr_t iova; + int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO; + size_t size = cookie_msi_granule(cookie); + + msi_addr &= ~(phys_addr_t)(size - 1); + list_for_each_entry(msi_page, &cookie->msi_page_list, list) + if (msi_page->phys == msi_addr) + return msi_page; + + msi_page = kzalloc(sizeof(*msi_page), GFP_KERNEL); + if (!msi_page) + return NULL; + + iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev), dev); + if (!iova) + goto out_free_page; + + if (iommu_map(domain, iova, msi_addr, size, prot)) + goto out_free_iova; + + INIT_LIST_HEAD(&msi_page->list); + msi_page->phys = msi_addr; + msi_page->iova = iova; + list_add(&msi_page->list, &cookie->msi_page_list); + return msi_page; + +out_free_iova: + iommu_dma_free_iova(cookie, iova, size); +out_free_page: + kfree(msi_page); + return NULL; +} + +int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr) +{ + struct device *dev = msi_desc_to_dev(desc); + struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + struct iommu_dma_msi_page *msi_page; + static DEFINE_MUTEX(msi_prepare_lock); /* see below */ + + if (!domain || !domain->iova_cookie) { + desc->iommu_cookie = NULL; + return 0; + } + + /* + * In fact the whole prepare operation should already be serialised by + * irq_domain_mutex further up the callchain, but that's pretty subtle + * on its own, so consider this locking as failsafe documentation... + */ + mutex_lock(&msi_prepare_lock); + msi_page = iommu_dma_get_msi_page(dev, msi_addr, domain); + mutex_unlock(&msi_prepare_lock); + + msi_desc_set_iommu_cookie(desc, msi_page); + + if (!msi_page) + return -ENOMEM; + return 0; +} + +void iommu_dma_compose_msi_msg(struct msi_desc *desc, + struct msi_msg *msg) +{ + struct device *dev = msi_desc_to_dev(desc); + const struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + const struct iommu_dma_msi_page *msi_page; + + msi_page = msi_desc_get_iommu_cookie(desc); + + if (!domain || !domain->iova_cookie || WARN_ON(!msi_page)) + return; + + msg->address_hi = upper_32_bits(msi_page->iova); + msg->address_lo &= cookie_msi_granule(domain->iova_cookie) - 1; + msg->address_lo += lower_32_bits(msi_page->iova); +} + +static int iommu_dma_init(void) +{ + return iova_cache_get(); +} +arch_initcall(iommu_dma_init); |