/* * linux/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. * * DMA uncached mapping support. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "mm.h" /* * The DMA API is built upon the notion of "buffer ownership". A buffer * is either exclusively owned by the CPU (and therefore may be accessed * by it) or exclusively owned by the DMA device. These helper functions * represent the transitions between these two ownership states. * * Note, however, that on later ARMs, this notion does not work due to * speculative prefetches. We model our approach on the assumption that * the CPU does do speculative prefetches, which means we clean caches * before transfers and delay cache invalidation until transfer completion. * */ static void __dma_page_cpu_to_dev(struct page *, unsigned long, size_t, enum dma_data_direction); static void __dma_page_dev_to_cpu(struct page *, unsigned long, size_t, enum dma_data_direction); /** * arm_dma_map_page - map a portion of a page for streaming DMA * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @page: page that buffer resides in * @offset: offset into page for start of buffer * @size: size of buffer to map * @dir: DMA transfer direction * * Ensure that any data held in the cache is appropriately discarded * or written back. * * The device owns this memory once this call has completed. The CPU * can regain ownership by calling dma_unmap_page(). */ static dma_addr_t arm_dma_map_page(struct device *dev, struct page *page, unsigned long offset, size_t size, enum dma_data_direction dir, struct dma_attrs *attrs) { if (!arch_is_coherent()) __dma_page_cpu_to_dev(page, offset, size, dir); return pfn_to_dma(dev, page_to_pfn(page)) + offset; } /** * arm_dma_unmap_page - unmap a buffer previously mapped through dma_map_page() * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @handle: DMA address of buffer * @size: size of buffer (same as passed to dma_map_page) * @dir: DMA transfer direction (same as passed to dma_map_page) * * Unmap a page streaming mode DMA translation. The handle and size * must match what was provided in the previous dma_map_page() call. * All other usages are undefined. * * After this call, reads by the CPU to the buffer are guaranteed to see * whatever the device wrote there. */ static void arm_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir, struct dma_attrs *attrs) { if (!arch_is_coherent()) __dma_page_dev_to_cpu(pfn_to_page(dma_to_pfn(dev, handle)), handle & ~PAGE_MASK, size, dir); } static void arm_dma_sync_single_for_cpu(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { unsigned int offset = handle & (PAGE_SIZE - 1); struct page *page = pfn_to_page(dma_to_pfn(dev, handle-offset)); if (!arch_is_coherent()) __dma_page_dev_to_cpu(page, offset, size, dir); } static void arm_dma_sync_single_for_device(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { unsigned int offset = handle & (PAGE_SIZE - 1); struct page *page = pfn_to_page(dma_to_pfn(dev, handle-offset)); if (!arch_is_coherent()) __dma_page_cpu_to_dev(page, offset, size, dir); } static int arm_dma_set_mask(struct device *dev, u64 dma_mask); struct dma_map_ops arm_dma_ops = { .alloc = arm_dma_alloc, .free = arm_dma_free, .mmap = arm_dma_mmap, .map_page = arm_dma_map_page, .unmap_page = arm_dma_unmap_page, .map_sg = arm_dma_map_sg, .unmap_sg = arm_dma_unmap_sg, .sync_single_for_cpu = arm_dma_sync_single_for_cpu, .sync_single_for_device = arm_dma_sync_single_for_device, .sync_sg_for_cpu = arm_dma_sync_sg_for_cpu, .sync_sg_for_device = arm_dma_sync_sg_for_device, .set_dma_mask = arm_dma_set_mask, }; EXPORT_SYMBOL(arm_dma_ops); static u64 get_coherent_dma_mask(struct device *dev) { u64 mask = (u64)arm_dma_limit; if (dev) { mask = dev->coherent_dma_mask; /* * Sanity check the DMA mask - it must be non-zero, and * must be able to be satisfied by a DMA allocation. */ if (mask == 0) { dev_warn(dev, "coherent DMA mask is unset\n"); return 0; } if ((~mask) & (u64)arm_dma_limit) { dev_warn(dev, "coherent DMA mask %#llx is smaller " "than system GFP_DMA mask %#llx\n", mask, (u64)arm_dma_limit); return 0; } } return mask; } static void __dma_clear_buffer(struct page *page, size_t size) { void *ptr; /* * Ensure that the allocated pages are zeroed, and that any data * lurking in the kernel direct-mapped region is invalidated. */ ptr = page_address(page); if (ptr) { memset(ptr, 0, size); dmac_flush_range(ptr, ptr + size); outer_flush_range(__pa(ptr), __pa(ptr) + size); } } /* * Allocate a DMA buffer for 'dev' of size 'size' using the * specified gfp mask. Note that 'size' must be page aligned. */ static struct page *__dma_alloc_buffer(struct device *dev, size_t size, gfp_t gfp) { unsigned long order = get_order(size); struct page *page, *p, *e; page = alloc_pages(gfp, order); if (!page) return NULL; /* * Now split the huge page and free the excess pages */ split_page(page, order); for (p = page + (size >> PAGE_SHIFT), e = page + (1 << order); p < e; p++) __free_page(p); __dma_clear_buffer(page, size); return page; } /* * Free a DMA buffer. 'size' must be page aligned. */ static void __dma_free_buffer(struct page *page, size_t size) { struct page *e = page + (size >> PAGE_SHIFT); while (page < e) { __free_page(page); page++; } } #ifdef CONFIG_MMU #ifdef CONFIG_HUGETLB_PAGE #error ARM Coherent DMA allocator does not (yet) support huge TLB #endif static void *__alloc_from_contiguous(struct device *dev, size_t size, pgprot_t prot, struct page **ret_page); static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp, pgprot_t prot, struct page **ret_page, const void *caller); static void * __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot, const void *caller) { struct vm_struct *area; unsigned long addr; /* * DMA allocation can be mapped to user space, so lets * set VM_USERMAP flags too. */ area = get_vm_area_caller(size, VM_ARM_DMA_CONSISTENT | VM_USERMAP, caller); if (!area) return NULL; addr = (unsigned long)area->addr; area->phys_addr = __pfn_to_phys(page_to_pfn(page)); if (ioremap_page_range(addr, addr + size, area->phys_addr, prot)) { vunmap((void *)addr); return NULL; } return (void *)addr; } static void __dma_free_remap(void *cpu_addr, size_t size) { unsigned int flags = VM_ARM_DMA_CONSISTENT | VM_USERMAP; struct vm_struct *area = find_vm_area(cpu_addr); if (!area || (area->flags & flags) != flags) { WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr); return; } unmap_kernel_range((unsigned long)cpu_addr, size); vunmap(cpu_addr); } struct dma_pool { size_t size; spinlock_t lock; unsigned long *bitmap; unsigned long nr_pages; void *vaddr; struct page *page; }; static struct dma_pool atomic_pool = { .size = SZ_256K, }; static int __init early_coherent_pool(char *p) { atomic_pool.size = memparse(p, &p); return 0; } early_param("coherent_pool", early_coherent_pool); /* * Initialise the coherent pool for atomic allocations. */ static int __init atomic_pool_init(void) { struct dma_pool *pool = &atomic_pool; pgprot_t prot = pgprot_dmacoherent(pgprot_kernel); unsigned long nr_pages = pool->size >> PAGE_SHIFT; unsigned long *bitmap; struct page *page; void *ptr; int bitmap_size = BITS_TO_LONGS(nr_pages) * sizeof(long); bitmap = kzalloc(bitmap_size, GFP_KERNEL); if (!bitmap) goto no_bitmap; if (IS_ENABLED(CONFIG_CMA)) ptr = __alloc_from_contiguous(NULL, pool->size, prot, &page); else ptr = __alloc_remap_buffer(NULL, pool->size, GFP_KERNEL, prot, &page, NULL); if (ptr) { spin_lock_init(&pool->lock); pool->vaddr = ptr; pool->page = page; pool->bitmap = bitmap; pool->nr_pages = nr_pages; pr_info("DMA: preallocated %u KiB pool for atomic coherent allocations\n", (unsigned)pool->size / 1024); return 0; } kfree(bitmap); no_bitmap: pr_err("DMA: failed to allocate %u KiB pool for atomic coherent allocation\n", (unsigned)pool->size / 1024); return -ENOMEM; } /* * CMA is activated by core_initcall, so we must be called after it. */ postcore_initcall(atomic_pool_init); struct dma_contig_early_reserve { phys_addr_t base; unsigned long size; }; static struct dma_contig_early_reserve dma_mmu_remap[MAX_CMA_AREAS] __initdata; static int dma_mmu_remap_num __initdata; void __init dma_contiguous_early_fixup(phys_addr_t base, unsigned long size) { dma_mmu_remap[dma_mmu_remap_num].base = base; dma_mmu_remap[dma_mmu_remap_num].size = size; dma_mmu_remap_num++; } void __init dma_contiguous_remap(void) { int i; for (i = 0; i < dma_mmu_remap_num; i++) { phys_addr_t start = dma_mmu_remap[i].base; phys_addr_t end = start + dma_mmu_remap[i].size; struct map_desc map; unsigned long addr; if (end > arm_lowmem_limit) end = arm_lowmem_limit; if (start >= end) return; map.pfn = __phys_to_pfn(start); map.virtual = __phys_to_virt(start); map.length = end - start; map.type = MT_MEMORY_DMA_READY; /* * Clear previous low-memory mapping */ for (addr = __phys_to_virt(start); addr < __phys_to_virt(end); addr += PMD_SIZE) pmd_clear(pmd_off_k(addr)); iotable_init(&map, 1); } } static int __dma_update_pte(pte_t *pte, pgtable_t token, unsigned long addr, void *data) { struct page *page = virt_to_page(addr); pgprot_t prot = *(pgprot_t *)data; set_pte_ext(pte, mk_pte(page, prot), 0); return 0; } static void __dma_remap(struct page *page, size_t size, pgprot_t prot) { unsigned long start = (unsigned long) page_address(page); unsigned end = start + size; apply_to_page_range(&init_mm, start, size, __dma_update_pte, &prot); dsb(); flush_tlb_kernel_range(start, end); } static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp, pgprot_t prot, struct page **ret_page, const void *caller) { struct page *page; void *ptr; page = __dma_alloc_buffer(dev, size, gfp); if (!page) return NULL; ptr = __dma_alloc_remap(page, size, gfp, prot, caller); if (!ptr) { __dma_free_buffer(page, size); return NULL; } *ret_page = page; return ptr; } static void *__alloc_from_pool(size_t size, struct page **ret_page) { struct dma_pool *pool = &atomic_pool; unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; unsigned int pageno; unsigned long flags; void *ptr = NULL; size_t align; if (!pool->vaddr) { WARN(1, "coherent pool not initialised!\n"); return NULL; } /* * Align the region allocation - allocations from pool are rather * small, so align them to their order in pages, minimum is a page * size. This helps reduce fragmentation of the DMA space. */ align = PAGE_SIZE << get_order(size); spin_lock_irqsave(&pool->lock, flags); pageno = bitmap_find_next_zero_area(pool->bitmap, pool->nr_pages, 0, count, (1 << align) - 1); if (pageno < pool->nr_pages) { bitmap_set(pool->bitmap, pageno, count); ptr = pool->vaddr + PAGE_SIZE * pageno; *ret_page = pool->page + pageno; } spin_unlock_irqrestore(&pool->lock, flags); return ptr; } static int __free_from_pool(void *start, size_t size) { struct dma_pool *pool = &atomic_pool; unsigned long pageno, count; unsigned long flags; if (start < pool->vaddr || start > pool->vaddr + pool->size) return 0; if (start + size > pool->vaddr + pool->size) { WARN(1, "freeing wrong coherent size from pool\n"); return 0; } pageno = (start - pool->vaddr) >> PAGE_SHIFT; count = size >> PAGE_SHIFT; spin_lock_irqsave(&pool->lock, flags); bitmap_clear(pool->bitmap, pageno, count); spin_unlock_irqrestore(&pool->lock, flags); return 1; } static void *__alloc_from_contiguous(struct device *dev, size_t size, pgprot_t prot, struct page **ret_page) { unsigned long order = get_order(size); size_t count = size >> PAGE_SHIFT; struct page *page; page = dma_alloc_from_contiguous(dev, count, order); if (!page) return NULL; __dma_clear_buffer(page, size); __dma_remap(page, size, prot); *ret_page = page; return page_address(page); } static void __free_from_contiguous(struct device *dev, struct page *page, size_t size) { __dma_remap(page, size, pgprot_kernel); dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT); } static inline pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot) { prot = dma_get_attr(DMA_ATTR_WRITE_COMBINE, attrs) ? pgprot_writecombine(prot) : pgprot_dmacoherent(prot); return prot; } #define nommu() 0 #else /* !CONFIG_MMU */ #define nommu() 1 #define __get_dma_pgprot(attrs, prot) __pgprot(0) #define __alloc_remap_buffer(dev, size, gfp, prot, ret, c) NULL #define __alloc_from_pool(size, ret_page) NULL #define __alloc_from_contiguous(dev, size, prot, ret) NULL #define __free_from_pool(cpu_addr, size) 0 #define __free_from_contiguous(dev, page, size) do { } while (0) #define __dma_free_remap(cpu_addr, size) do { } while (0) #endif /* CONFIG_MMU */ static void *__alloc_simple_buffer(struct device *dev, size_t size, gfp_t gfp, struct page **ret_page) { struct page *page; page = __dma_alloc_buffer(dev, size, gfp); if (!page) return NULL; *ret_page = page; return page_address(page); } static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, pgprot_t prot, const void *caller) { u64 mask = get_coherent_dma_mask(dev); struct page *page; void *addr; #ifdef CONFIG_DMA_API_DEBUG u64 limit = (mask + 1) & ~mask; if (limit && size >= limit) { dev_warn(dev, "coherent allocation too big (requested %#x mask %#llx)\n", size, mask); return NULL; } #endif if (!mask) return NULL; if (mask < 0xffffffffULL) gfp |= GFP_DMA; /* * Following is a work-around (a.k.a. hack) to prevent pages * with __GFP_COMP being passed to split_page() which cannot * handle them. The real problem is that this flag probably * should be 0 on ARM as it is not supported on this * platform; see CONFIG_HUGETLBFS. */ gfp &= ~(__GFP_COMP); *handle = DMA_ERROR_CODE; size = PAGE_ALIGN(size); if (arch_is_coherent() || nommu()) addr = __alloc_simple_buffer(dev, size, gfp, &page); else if (gfp & GFP_ATOMIC) addr = __alloc_from_pool(size, &page); else if (!IS_ENABLED(CONFIG_CMA)) addr = __alloc_remap_buffer(dev, size, gfp, prot, &page, caller); else addr = __alloc_from_contiguous(dev, size, prot, &page); if (addr) *handle = pfn_to_dma(dev, page_to_pfn(page)); return addr; } /* * Allocate DMA-coherent memory space and return both the kernel remapped * virtual and bus address for that space. */ void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs) { pgprot_t prot = __get_dma_pgprot(attrs, pgprot_kernel); void *memory; if (dma_alloc_from_coherent(dev, size, handle, &memory)) return memory; return __dma_alloc(dev, size, handle, gfp, prot, __builtin_return_address(0)); } /* * Create userspace mapping for the DMA-coherent memory. */ int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t dma_addr, size_t size, struct dma_attrs *attrs) { int ret = -ENXIO; #ifdef CONFIG_MMU unsigned long nr_vma_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; unsigned long pfn = dma_to_pfn(dev, dma_addr); unsigned long off = vma->vm_pgoff; vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot); if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret)) return ret; if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) { ret = remap_pfn_range(vma, vma->vm_start, pfn + off, vma->vm_end - vma->vm_start, vma->vm_page_prot); } #endif /* CONFIG_MMU */ return ret; } /* * Free a buffer as defined by the above mapping. */ void arm_dma_free(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle, struct dma_attrs *attrs) { struct page *page = pfn_to_page(dma_to_pfn(dev, handle)); if (dma_release_from_coherent(dev, get_order(size), cpu_addr)) return; size = PAGE_ALIGN(size); if (arch_is_coherent() || nommu()) { __dma_free_buffer(page, size); } else if (!IS_ENABLED(CONFIG_CMA)) { __dma_free_remap(cpu_addr, size); __dma_free_buffer(page, size); } else { if (__free_from_pool(cpu_addr, size)) return; /* * Non-atomic allocations cannot be freed with IRQs disabled */ WARN_ON(irqs_disabled()); __free_from_contiguous(dev, page, size); } } static void dma_cache_maint_page(struct page *page, unsigned long offset, size_t size, enum dma_data_direction dir, void (*op)(const void *, size_t, int)) { /* * A single sg entry may refer to multiple physically contiguous * pages. But we still need to process highmem pages individually. * If highmem is not configured then the bulk of this loop gets * optimized out. */ size_t left = size; do { size_t len = left; void *vaddr; if (PageHighMem(page)) { if (len + offset > PAGE_SIZE) { if (offset >= PAGE_SIZE) { page += offset / PAGE_SIZE; offset %= PAGE_SIZE; } len = PAGE_SIZE - offset; } vaddr = kmap_high_get(page); if (vaddr) { vaddr += offset; op(vaddr, len, dir); kunmap_high(page); } else if (cache_is_vipt()) { /* unmapped pages might still be cached */ vaddr = kmap_atomic(page); op(vaddr + offset, len, dir); kunmap_atomic(vaddr); } } else { vaddr = page_address(page) + offset; op(vaddr, len, dir); } offset = 0; page++; left -= len; } while (left); } /* * Make an area consistent for devices. * Note: Drivers should NOT use this function directly, as it will break * platforms with CONFIG_DMABOUNCE. * Use the driver DMA support - see dma-mapping.h (dma_sync_*) */ static void __dma_page_cpu_to_dev(struct page *page, unsigned long off, size_t size, enum dma_data_direction dir) { unsigned long paddr; dma_cache_maint_page(page, off, size, dir, dmac_map_area); paddr = page_to_phys(page) + off; if (dir == DMA_FROM_DEVICE) { outer_inv_range(paddr, paddr + size); } else { outer_clean_range(paddr, paddr + size); } /* FIXME: non-speculating: flush on bidirectional mappings? */ } static void __dma_page_dev_to_cpu(struct page *page, unsigned long off, size_t size, enum dma_data_direction dir) { unsigned long paddr = page_to_phys(page) + off; /* FIXME: non-speculating: not required */ /* don't bother invalidating if DMA to device */ if (dir != DMA_TO_DEVICE) outer_inv_range(paddr, paddr + size); dma_cache_maint_page(page, off, size, dir, dmac_unmap_area); /* * Mark the D-cache clean for this page to avoid extra flushing. */ if (dir != DMA_TO_DEVICE && off == 0 && size >= PAGE_SIZE) set_bit(PG_dcache_clean, &page->flags); } /** * arm_dma_map_sg - map a set of SG buffers for streaming mode DMA * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @sg: list of buffers * @nents: number of buffers to map * @dir: DMA transfer direction * * Map a set of buffers described by scatterlist in streaming mode for DMA. * This is the scatter-gather version of the dma_map_single interface. * Here the scatter gather list elements are each tagged with the * appropriate dma address and length. They are obtained via * sg_dma_{address,length}. * * Device ownership issues as mentioned for dma_map_single are the same * here. */ int arm_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, struct dma_attrs *attrs) { struct dma_map_ops *ops = get_dma_ops(dev); struct scatterlist *s; int i, j; for_each_sg(sg, s, nents, i) { #ifdef CONFIG_NEED_SG_DMA_LENGTH s->dma_length = s->length; #endif s->dma_address = ops->map_page(dev, sg_page(s), s->offset, s->length, dir, attrs); if (dma_mapping_error(dev, s->dma_address)) goto bad_mapping; } return nents; bad_mapping: for_each_sg(sg, s, i, j) ops->unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir, attrs); return 0; } /** * arm_dma_unmap_sg - unmap a set of SG buffers mapped by dma_map_sg * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @sg: list of buffers * @nents: number of buffers to unmap (same as was passed to dma_map_sg) * @dir: DMA transfer direction (same as was passed to dma_map_sg) * * Unmap a set of streaming mode DMA translations. Again, CPU access * rules concerning calls here are the same as for dma_unmap_single(). */ void arm_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, struct dma_attrs *attrs) { struct dma_map_ops *ops = get_dma_ops(dev); struct scatterlist *s; int i; for_each_sg(sg, s, nents, i) ops->unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir, attrs); } /** * arm_dma_sync_sg_for_cpu * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @sg: list of buffers * @nents: number of buffers to map (returned from dma_map_sg) * @dir: DMA transfer direction (same as was passed to dma_map_sg) */ void arm_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir) { struct dma_map_ops *ops = get_dma_ops(dev); struct scatterlist *s; int i; for_each_sg(sg, s, nents, i) ops->sync_single_for_cpu(dev, sg_dma_address(s), s->length, dir); } /** * arm_dma_sync_sg_for_device * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @sg: list of buffers * @nents: number of buffers to map (returned from dma_map_sg) * @dir: DMA transfer direction (same as was passed to dma_map_sg) */ void arm_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir) { struct dma_map_ops *ops = get_dma_ops(dev); struct scatterlist *s; int i; for_each_sg(sg, s, nents, i) ops->sync_single_for_device(dev, sg_dma_address(s), s->length, dir); } /* * Return whether the given device DMA address mask can be supported * properly. For example, if your device can only drive the low 24-bits * during bus mastering, then you would pass 0x00ffffff as the mask * to this function. */ int dma_supported(struct device *dev, u64 mask) { if (mask < (u64)arm_dma_limit) return 0; return 1; } EXPORT_SYMBOL(dma_supported); static int arm_dma_set_mask(struct device *dev, u64 dma_mask) { if (!dev->dma_mask || !dma_supported(dev, dma_mask)) return -EIO; *dev->dma_mask = dma_mask; return 0; } #define PREALLOC_DMA_DEBUG_ENTRIES 4096 static int __init dma_debug_do_init(void) { dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); return 0; } fs_initcall(dma_debug_do_init); #ifdef CONFIG_ARM_DMA_USE_IOMMU /* IOMMU */ static inline dma_addr_t __alloc_iova(struct dma_iommu_mapping *mapping, size_t size) { unsigned int order = get_order(size); unsigned int align = 0; unsigned int count, start; unsigned long flags; count = ((PAGE_ALIGN(size) >> PAGE_SHIFT) + (1 << mapping->order) - 1) >> mapping->order; if (order > mapping->order) align = (1 << (order - mapping->order)) - 1; spin_lock_irqsave(&mapping->lock, flags); start = bitmap_find_next_zero_area(mapping->bitmap, mapping->bits, 0, count, align); if (start > mapping->bits) { spin_unlock_irqrestore(&mapping->lock, flags); return DMA_ERROR_CODE; } bitmap_set(mapping->bitmap, start, count); spin_unlock_irqrestore(&mapping->lock, flags); return mapping->base + (start << (mapping->order + PAGE_SHIFT)); } static inline void __free_iova(struct dma_iommu_mapping *mapping, dma_addr_t addr, size_t size) { unsigned int start = (addr - mapping->base) >> (mapping->order + PAGE_SHIFT); unsigned int count = ((size >> PAGE_SHIFT) + (1 << mapping->order) - 1) >> mapping->order; unsigned long flags; spin_lock_irqsave(&mapping->lock, flags); bitmap_clear(mapping->bitmap, start, count); spin_unlock_irqrestore(&mapping->lock, flags); } static struct page **__iommu_alloc_buffer(struct device *dev, size_t size, gfp_t gfp) { struct page **pages; int count = size >> PAGE_SHIFT; int array_size = count * sizeof(struct page *); int i = 0; if (array_size <= PAGE_SIZE) pages = kzalloc(array_size, gfp); else pages = vzalloc(array_size); if (!pages) return NULL; while (count) { int j, order = __fls(count); pages[i] = alloc_pages(gfp | __GFP_NOWARN, order); while (!pages[i] && order) pages[i] = alloc_pages(gfp | __GFP_NOWARN, --order); if (!pages[i]) goto error; if (order) split_page(pages[i], order); j = 1 << order; while (--j) pages[i + j] = pages[i] + j; __dma_clear_buffer(pages[i], PAGE_SIZE << order); i += 1 << order; count -= 1 << order; } return pages; error: while (i--) if (pages[i]) __free_pages(pages[i], 0); if (array_size <= PAGE_SIZE) kfree(pages); else vfree(pages); return NULL; } static int __iommu_free_buffer(struct device *dev, struct page **pages, size_t size) { int count = size >> PAGE_SHIFT; int array_size = count * sizeof(struct page *); int i; for (i = 0; i < count; i++) if (pages[i]) __free_pages(pages[i], 0); if (array_size <= PAGE_SIZE) kfree(pages); else vfree(pages); return 0; } /* * Create a CPU mapping for a specified pages */ static void * __iommu_alloc_remap(struct page **pages, size_t size, gfp_t gfp, pgprot_t prot, const void *caller) { unsigned int i, nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; struct vm_struct *area; unsigned long p; area = get_vm_area_caller(size, VM_ARM_DMA_CONSISTENT | VM_USERMAP, caller); if (!area) return NULL; area->pages = pages; area->nr_pages = nr_pages; p = (unsigned long)area->addr; for (i = 0; i < nr_pages; i++) { phys_addr_t phys = __pfn_to_phys(page_to_pfn(pages[i])); if (ioremap_page_range(p, p + PAGE_SIZE, phys, prot)) goto err; p += PAGE_SIZE; } return area->addr; err: unmap_kernel_range((unsigned long)area->addr, size); vunmap(area->addr); return NULL; } /* * Create a mapping in device IO address space for specified pages */ static dma_addr_t __iommu_create_mapping(struct device *dev, struct page **pages, size_t size) { struct dma_iommu_mapping *mapping = dev->archdata.mapping; unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; dma_addr_t dma_addr, iova; int i, ret = DMA_ERROR_CODE; dma_addr = __alloc_iova(mapping, size); if (dma_addr == DMA_ERROR_CODE) return dma_addr; iova = dma_addr; for (i = 0; i < count; ) { unsigned int next_pfn = page_to_pfn(pages[i]) + 1; phys_addr_t phys = page_to_phys(pages[i]); unsigned int len, j; for (j = i + 1; j < count; j++, next_pfn++) if (page_to_pfn(pages[j]) != next_pfn) break; len = (j - i) << PAGE_SHIFT; ret = iommu_map(mapping->domain, iova, phys, len, 0); if (ret < 0) goto fail; iova += len; i = j; } return dma_addr; fail: iommu_unmap(mapping->domain, dma_addr, iova-dma_addr); __free_iova(mapping, dma_addr, size); return DMA_ERROR_CODE; } static int __iommu_remove_mapping(struct device *dev, dma_addr_t iova, size_t size) { struct dma_iommu_mapping *mapping = dev->archdata.mapping; /* * add optional in-page offset from iova to size and align * result to page size */ size = PAGE_ALIGN((iova & ~PAGE_MASK) + size); iova &= PAGE_MASK; iommu_unmap(mapping->domain, iova, size); __free_iova(mapping, iova, size); return 0; } static struct page **__iommu_get_pages(void *cpu_addr, struct dma_attrs *attrs) { struct vm_struct *area; if (dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs)) return cpu_addr; area = find_vm_area(cpu_addr); if (area && (area->flags & VM_ARM_DMA_CONSISTENT)) return area->pages; return NULL; } static void *arm_iommu_alloc_attrs(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs) { pgprot_t prot = __get_dma_pgprot(attrs, pgprot_kernel); struct page **pages; void *addr = NULL; *handle = DMA_ERROR_CODE; size = PAGE_ALIGN(size); pages = __iommu_alloc_buffer(dev, size, gfp); if (!pages) return NULL; *handle = __iommu_create_mapping(dev, pages, size); if (*handle == DMA_ERROR_CODE) goto err_buffer; if (dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs)) return pages; addr = __iommu_alloc_remap(pages, size, gfp, prot, __builtin_return_address(0)); if (!addr) goto err_mapping; return addr; err_mapping: __iommu_remove_mapping(dev, *handle, size); err_buffer: __iommu_free_buffer(dev, pages, size); return NULL; } static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t dma_addr, size_t size, struct dma_attrs *attrs) { unsigned long uaddr = vma->vm_start; unsigned long usize = vma->vm_end - vma->vm_start; struct page **pages = __iommu_get_pages(cpu_addr, attrs); vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot); if (!pages) return -ENXIO; do { int ret = vm_insert_page(vma, uaddr, *pages++); if (ret) { pr_err("Remapping memory failed: %d\n", ret); return ret; } uaddr += PAGE_SIZE; usize -= PAGE_SIZE; } while (usize > 0); return 0; } /* * free a page as defined by the above mapping. * Must not be called with IRQs disabled. */ void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle, struct dma_attrs *attrs) { struct page **pages = __iommu_get_pages(cpu_addr, attrs); size = PAGE_ALIGN(size); if (!pages) { WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr); return; } if (!dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs)) { unmap_kernel_range((unsigned long)cpu_addr, size); vunmap(cpu_addr); } __iommu_remove_mapping(dev, handle, size); __iommu_free_buffer(dev, pages, size); } /* * Map a part of the scatter-gather list into contiguous io address space */ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg, size_t size, dma_addr_t *handle, enum dma_data_direction dir) { struct dma_iommu_mapping *mapping = dev->archdata.mapping; dma_addr_t iova, iova_base; int ret = 0; unsigned int count; struct scatterlist *s; size = PAGE_ALIGN(size); *handle = DMA_ERROR_CODE; iova_base = iova = __alloc_iova(mapping, size); if (iova == DMA_ERROR_CODE) return -ENOMEM; for (count = 0, s = sg; count < (size >> PAGE_SHIFT); s = sg_next(s)) { phys_addr_t phys = page_to_phys(sg_page(s)); unsigned int len = PAGE_ALIGN(s->offset + s->length); if (!arch_is_coherent()) __dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir); ret = iommu_map(mapping->domain, iova, phys, len, 0); if (ret < 0) goto fail; count += len >> PAGE_SHIFT; iova += len; } *handle = iova_base; return 0; fail: iommu_unmap(mapping->domain, iova_base, count * PAGE_SIZE); __free_iova(mapping, iova_base, size); return ret; } /** * arm_iommu_map_sg - map a set of SG buffers for streaming mode DMA * @dev: valid struct device pointer * @sg: list of buffers * @nents: number of buffers to map * @dir: DMA transfer direction * * Map a set of buffers described by scatterlist in streaming mode for DMA. * The scatter gather list elements are merged together (if possible) and * tagged with the appropriate dma address and length. They are obtained via * sg_dma_{address,length}. */ int arm_iommu_map_sg(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, struct dma_attrs *attrs) { struct scatterlist *s = sg, *dma = sg, *start = sg; int i, count = 0; unsigned int offset = s->offset; unsigned int size = s->offset + s->length; unsigned int max = dma_get_max_seg_size(dev); for (i = 1; i < nents; i++) { s = sg_next(s); s->dma_address = DMA_ERROR_CODE; s->dma_length = 0; if (s->offset || (size & ~PAGE_MASK) || size + s->length > max) { if (__map_sg_chunk(dev, start, size, &dma->dma_address, dir) < 0) goto bad_mapping; dma->dma_address += offset; dma->dma_length = size - offset; size = offset = s->offset; start = s; dma = sg_next(dma); count += 1; } size += s->length; } if (__map_sg_chunk(dev, start, size, &dma->dma_address, dir) < 0) goto bad_mapping; dma->dma_address += offset; dma->dma_length = size - offset; return count+1; bad_mapping: for_each_sg(sg, s, count, i) __iommu_remove_mapping(dev, sg_dma_address(s), sg_dma_len(s)); return 0; } /** * arm_iommu_unmap_sg - unmap a set of SG buffers mapped by dma_map_sg * @dev: valid struct device pointer * @sg: list of buffers * @nents: number of buffers to unmap (same as was passed to dma_map_sg) * @dir: DMA transfer direction (same as was passed to dma_map_sg) * * Unmap a set of streaming mode DMA translations. Again, CPU access * rules concerning calls here are the same as for dma_unmap_single(). */ void arm_iommu_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, struct dma_attrs *attrs) { struct scatterlist *s; int i; for_each_sg(sg, s, nents, i) { if (sg_dma_len(s)) __iommu_remove_mapping(dev, sg_dma_address(s), sg_dma_len(s)); if (!arch_is_coherent()) __dma_page_dev_to_cpu(sg_page(s), s->offset, s->length, dir); } } /** * arm_iommu_sync_sg_for_cpu * @dev: valid struct device pointer * @sg: list of buffers * @nents: number of buffers to map (returned from dma_map_sg) * @dir: DMA transfer direction (same as was passed to dma_map_sg) */ void arm_iommu_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir) { struct scatterlist *s; int i; for_each_sg(sg, s, nents, i) if (!arch_is_coherent()) __dma_page_dev_to_cpu(sg_page(s), s->offset, s->length, dir); } /** * arm_iommu_sync_sg_for_device * @dev: valid struct device pointer * @sg: list of buffers * @nents: number of buffers to map (returned from dma_map_sg) * @dir: DMA transfer direction (same as was passed to dma_map_sg) */ void arm_iommu_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir) { struct scatterlist *s; int i; for_each_sg(sg, s, nents, i) if (!arch_is_coherent()) __dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir); } /** * arm_iommu_map_page * @dev: valid struct device pointer * @page: page that buffer resides in * @offset: offset into page for start of buffer * @size: size of buffer to map * @dir: DMA transfer direction * * IOMMU aware version of arm_dma_map_page() */ static dma_addr_t arm_iommu_map_page(struct device *dev, struct page *page, unsigned long offset, size_t size, enum dma_data_direction dir, struct dma_attrs *attrs) { struct dma_iommu_mapping *mapping = dev->archdata.mapping; dma_addr_t dma_addr; int ret, len = PAGE_ALIGN(size + offset); if (!arch_is_coherent()) __dma_page_cpu_to_dev(page, offset, size, dir); dma_addr = __alloc_iova(mapping, len); if (dma_addr == DMA_ERROR_CODE) return dma_addr; ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, 0); if (ret < 0) goto fail; return dma_addr + offset; fail: __free_iova(mapping, dma_addr, len); return DMA_ERROR_CODE; } /** * arm_iommu_unmap_page * @dev: valid struct device pointer * @handle: DMA address of buffer * @size: size of buffer (same as passed to dma_map_page) * @dir: DMA transfer direction (same as passed to dma_map_page) * * IOMMU aware version of arm_dma_unmap_page() */ static void arm_iommu_unmap_page(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir, struct dma_attrs *attrs) { struct dma_iommu_mapping *mapping = dev->archdata.mapping; dma_addr_t iova = handle & PAGE_MASK; struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova)); int offset = handle & ~PAGE_MASK; int len = PAGE_ALIGN(size + offset); if (!iova) return; if (!arch_is_coherent()) __dma_page_dev_to_cpu(page, offset, size, dir); iommu_unmap(mapping->domain, iova, len); __free_iova(mapping, iova, len); } static void arm_iommu_sync_single_for_cpu(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { struct dma_iommu_mapping *mapping = dev->archdata.mapping; dma_addr_t iova = handle & PAGE_MASK; struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova)); unsigned int offset = handle & ~PAGE_MASK; if (!iova) return; if (!arch_is_coherent()) __dma_page_dev_to_cpu(page, offset, size, dir); } static void arm_iommu_sync_single_for_device(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { struct dma_iommu_mapping *mapping = dev->archdata.mapping; dma_addr_t iova = handle & PAGE_MASK; struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova)); unsigned int offset = handle & ~PAGE_MASK; if (!iova) return; __dma_page_cpu_to_dev(page, offset, size, dir); } struct dma_map_ops iommu_ops = { .alloc = arm_iommu_alloc_attrs, .free = arm_iommu_free_attrs, .mmap = arm_iommu_mmap_attrs, .map_page = arm_iommu_map_page, .unmap_page = arm_iommu_unmap_page, .sync_single_for_cpu = arm_iommu_sync_single_for_cpu, .sync_single_for_device = arm_iommu_sync_single_for_device, .map_sg = arm_iommu_map_sg, .unmap_sg = arm_iommu_unmap_sg, .sync_sg_for_cpu = arm_iommu_sync_sg_for_cpu, .sync_sg_for_device = arm_iommu_sync_sg_for_device, }; /** * arm_iommu_create_mapping * @bus: pointer to the bus holding the client device (for IOMMU calls) * @base: start address of the valid IO address space * @size: size of the valid IO address space * @order: accuracy of the IO addresses allocations * * Creates a mapping structure which holds information about used/unused * IO address ranges, which is required to perform memory allocation and * mapping with IOMMU aware functions. * * The client device need to be attached to the mapping with * arm_iommu_attach_device function. */ struct dma_iommu_mapping * arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size, int order) { unsigned int count = size >> (PAGE_SHIFT + order); unsigned int bitmap_size = BITS_TO_LONGS(count) * sizeof(long); struct dma_iommu_mapping *mapping; int err = -ENOMEM; if (!count) return ERR_PTR(-EINVAL); mapping = kzalloc(sizeof(struct dma_iommu_mapping), GFP_KERNEL); if (!mapping) goto err; mapping->bitmap = kzalloc(bitmap_size, GFP_KERNEL); if (!mapping->bitmap) goto err2; mapping->base = base; mapping->bits = BITS_PER_BYTE * bitmap_size; mapping->order = order; spin_lock_init(&mapping->lock); mapping->domain = iommu_domain_alloc(bus); if (!mapping->domain) goto err3; kref_init(&mapping->kref); return mapping; err3: kfree(mapping->bitmap); err2: kfree(mapping); err: return ERR_PTR(err); } static void release_iommu_mapping(struct kref *kref) { struct dma_iommu_mapping *mapping = container_of(kref, struct dma_iommu_mapping, kref); iommu_domain_free(mapping->domain); kfree(mapping->bitmap); kfree(mapping); } void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping) { if (mapping) kref_put(&mapping->kref, release_iommu_mapping); } /** * arm_iommu_attach_device * @dev: valid struct device pointer * @mapping: io address space mapping structure (returned from * arm_iommu_create_mapping) * * Attaches specified io address space mapping to the provided device, * this replaces the dma operations (dma_map_ops pointer) with the * IOMMU aware version. More than one client might be attached to * the same io address space mapping. */ int arm_iommu_attach_device(struct device *dev, struct dma_iommu_mapping *mapping) { int err; err = iommu_attach_device(mapping->domain, dev); if (err) return err; kref_get(&mapping->kref); dev->archdata.mapping = mapping; set_dma_ops(dev, &iommu_ops); pr_info("Attached IOMMU controller to %s device.\n", dev_name(dev)); return 0; } #endif