// SPDX-License-Identifier: GPL-2.0 /* * arch-independent dma-mapping routines * * Copyright (c) 2006 SUSE Linux Products GmbH * Copyright (c) 2006 Tejun Heo */ #include /* for max_pfn */ #include #include #include #include #include #include #include #include /* * Managed DMA API */ struct dma_devres { size_t size; void *vaddr; dma_addr_t dma_handle; unsigned long attrs; }; static void dmam_release(struct device *dev, void *res) { struct dma_devres *this = res; dma_free_attrs(dev, this->size, this->vaddr, this->dma_handle, this->attrs); } static int dmam_match(struct device *dev, void *res, void *match_data) { struct dma_devres *this = res, *match = match_data; if (this->vaddr == match->vaddr) { WARN_ON(this->size != match->size || this->dma_handle != match->dma_handle); return 1; } return 0; } /** * dmam_free_coherent - Managed dma_free_coherent() * @dev: Device to free coherent memory for * @size: Size of allocation * @vaddr: Virtual address of the memory to free * @dma_handle: DMA handle of the memory to free * * Managed dma_free_coherent(). */ void dmam_free_coherent(struct device *dev, size_t size, void *vaddr, dma_addr_t dma_handle) { struct dma_devres match_data = { size, vaddr, dma_handle }; dma_free_coherent(dev, size, vaddr, dma_handle); WARN_ON(devres_destroy(dev, dmam_release, dmam_match, &match_data)); } EXPORT_SYMBOL(dmam_free_coherent); /** * dmam_alloc_attrs - Managed dma_alloc_attrs() * @dev: Device to allocate non_coherent memory for * @size: Size of allocation * @dma_handle: Out argument for allocated DMA handle * @gfp: Allocation flags * @attrs: Flags in the DMA_ATTR_* namespace. * * Managed dma_alloc_attrs(). Memory allocated using this function will be * automatically released on driver detach. * * RETURNS: * Pointer to allocated memory on success, NULL on failure. */ void *dmam_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) { struct dma_devres *dr; void *vaddr; dr = devres_alloc(dmam_release, sizeof(*dr), gfp); if (!dr) return NULL; vaddr = dma_alloc_attrs(dev, size, dma_handle, gfp, attrs); if (!vaddr) { devres_free(dr); return NULL; } dr->vaddr = vaddr; dr->dma_handle = *dma_handle; dr->size = size; dr->attrs = attrs; devres_add(dev, dr); return vaddr; } EXPORT_SYMBOL(dmam_alloc_attrs); /* * Create scatter-list for the already allocated DMA buffer. */ int dma_common_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 = virt_to_page(cpu_addr); int ret; ret = sg_alloc_table(sgt, 1, GFP_KERNEL); if (!ret) sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0); return ret; } /* * The whole dma_get_sgtable() idea is fundamentally unsafe - it seems * that the intention is to allow exporting memory allocated via the * coherent DMA APIs through the dma_buf API, which only accepts a * scattertable. This presents a couple of problems: * 1. Not all memory allocated via the coherent DMA APIs is backed by * a struct page * 2. Passing coherent DMA memory into the streaming APIs is not allowed * as we will try to flush the memory through a different alias to that * actually being used (and the flushes are redundant.) */ int dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr, dma_addr_t dma_addr, size_t size, unsigned long attrs) { const struct dma_map_ops *ops = get_dma_ops(dev); if (dma_is_direct(ops)) return dma_direct_get_sgtable(dev, sgt, cpu_addr, dma_addr, size, attrs); if (!ops->get_sgtable) return -ENXIO; return ops->get_sgtable(dev, sgt, cpu_addr, dma_addr, size, attrs); } EXPORT_SYMBOL(dma_get_sgtable_attrs); #ifdef CONFIG_MMU /* * Return the page attributes used for mapping dma_alloc_* memory, either in * kernel space if remapping is needed, or to userspace through dma_mmap_*. */ pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs) { if (dev_is_dma_coherent(dev) || (IS_ENABLED(CONFIG_DMA_NONCOHERENT_CACHE_SYNC) && (attrs & DMA_ATTR_NON_CONSISTENT))) return prot; #ifdef CONFIG_ARCH_HAS_DMA_WRITE_COMBINE if (attrs & DMA_ATTR_WRITE_COMBINE) return pgprot_writecombine(prot); #endif return pgprot_dmacoherent(prot); } #endif /* CONFIG_MMU */ /* * Create userspace mapping for the DMA-coherent memory. */ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t dma_addr, size_t size, unsigned long attrs) { #ifdef CONFIG_MMU unsigned long user_count = vma_pages(vma); unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT; unsigned long off = vma->vm_pgoff; int ret = -ENXIO; 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 >= count || user_count > count - off) return -ENXIO; return remap_pfn_range(vma, vma->vm_start, page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff, user_count << PAGE_SHIFT, vma->vm_page_prot); #else return -ENXIO; #endif /* CONFIG_MMU */ } /** * dma_can_mmap - check if a given device supports dma_mmap_* * @dev: device to check * * Returns %true if @dev supports dma_mmap_coherent() and dma_mmap_attrs() to * map DMA allocations to userspace. */ bool dma_can_mmap(struct device *dev) { const struct dma_map_ops *ops = get_dma_ops(dev); if (dma_is_direct(ops)) return dma_direct_can_mmap(dev); return ops->mmap != NULL; } EXPORT_SYMBOL_GPL(dma_can_mmap); /** * dma_mmap_attrs - map a coherent DMA allocation into user space * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @vma: vm_area_struct describing requested user mapping * @cpu_addr: kernel CPU-view address returned from dma_alloc_attrs * @dma_addr: device-view address returned from dma_alloc_attrs * @size: size of memory originally requested in dma_alloc_attrs * @attrs: attributes of mapping properties requested in dma_alloc_attrs * * Map a coherent DMA buffer previously allocated by dma_alloc_attrs into user * space. The coherent DMA buffer must not be freed by the driver until the * user space mapping has been released. */ int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t dma_addr, size_t size, unsigned long attrs) { const struct dma_map_ops *ops = get_dma_ops(dev); if (dma_is_direct(ops)) return dma_direct_mmap(dev, vma, cpu_addr, dma_addr, size, attrs); if (!ops->mmap) return -ENXIO; return ops->mmap(dev, vma, cpu_addr, dma_addr, size, attrs); } EXPORT_SYMBOL(dma_mmap_attrs); u64 dma_get_required_mask(struct device *dev) { const struct dma_map_ops *ops = get_dma_ops(dev); if (dma_is_direct(ops)) return dma_direct_get_required_mask(dev); if (ops->get_required_mask) return ops->get_required_mask(dev); /* * We require every DMA ops implementation to at least support a 32-bit * DMA mask (and use bounce buffering if that isn't supported in * hardware). As the direct mapping code has its own routine to * actually report an optimal mask we default to 32-bit here as that * is the right thing for most IOMMUs, and at least not actively * harmful in general. */ return DMA_BIT_MASK(32); } EXPORT_SYMBOL_GPL(dma_get_required_mask); void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t flag, unsigned long attrs) { const struct dma_map_ops *ops = get_dma_ops(dev); void *cpu_addr; WARN_ON_ONCE(!dev->coherent_dma_mask); if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr)) return cpu_addr; /* let the implementation decide on the zone to allocate from: */ flag &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM); if (dma_is_direct(ops)) cpu_addr = dma_direct_alloc(dev, size, dma_handle, flag, attrs); else if (ops->alloc) cpu_addr = ops->alloc(dev, size, dma_handle, flag, attrs); else return NULL; debug_dma_alloc_coherent(dev, size, *dma_handle, cpu_addr); return cpu_addr; } EXPORT_SYMBOL(dma_alloc_attrs); void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_handle, unsigned long attrs) { const struct dma_map_ops *ops = get_dma_ops(dev); if (dma_release_from_dev_coherent(dev, get_order(size), cpu_addr)) return; /* * On non-coherent platforms which implement DMA-coherent buffers via * non-cacheable remaps, ops->free() may call vunmap(). Thus getting * this far in IRQ context is a) at risk of a BUG_ON() or trying to * sleep on some machines, and b) an indication that the driver is * probably misusing the coherent API anyway. */ WARN_ON(irqs_disabled()); if (!cpu_addr) return; debug_dma_free_coherent(dev, size, cpu_addr, dma_handle); if (dma_is_direct(ops)) dma_direct_free(dev, size, cpu_addr, dma_handle, attrs); else if (ops->free) ops->free(dev, size, cpu_addr, dma_handle, attrs); } EXPORT_SYMBOL(dma_free_attrs); int dma_supported(struct device *dev, u64 mask) { const struct dma_map_ops *ops = get_dma_ops(dev); if (dma_is_direct(ops)) return dma_direct_supported(dev, mask); if (!ops->dma_supported) return 1; return ops->dma_supported(dev, mask); } EXPORT_SYMBOL(dma_supported); #ifdef CONFIG_ARCH_HAS_DMA_SET_MASK void arch_dma_set_mask(struct device *dev, u64 mask); #else #define arch_dma_set_mask(dev, mask) do { } while (0) #endif int dma_set_mask(struct device *dev, u64 mask) { /* * Truncate the mask to the actually supported dma_addr_t width to * avoid generating unsupportable addresses. */ mask = (dma_addr_t)mask; if (!dev->dma_mask || !dma_supported(dev, mask)) return -EIO; arch_dma_set_mask(dev, mask); *dev->dma_mask = mask; return 0; } EXPORT_SYMBOL(dma_set_mask); #ifndef CONFIG_ARCH_HAS_DMA_SET_COHERENT_MASK int dma_set_coherent_mask(struct device *dev, u64 mask) { /* * Truncate the mask to the actually supported dma_addr_t width to * avoid generating unsupportable addresses. */ mask = (dma_addr_t)mask; if (!dma_supported(dev, mask)) return -EIO; dev->coherent_dma_mask = mask; return 0; } EXPORT_SYMBOL(dma_set_coherent_mask); #endif void dma_cache_sync(struct device *dev, void *vaddr, size_t size, enum dma_data_direction dir) { const struct dma_map_ops *ops = get_dma_ops(dev); BUG_ON(!valid_dma_direction(dir)); if (dma_is_direct(ops)) arch_dma_cache_sync(dev, vaddr, size, dir); else if (ops->cache_sync) ops->cache_sync(dev, vaddr, size, dir); } EXPORT_SYMBOL(dma_cache_sync); size_t dma_max_mapping_size(struct device *dev) { const struct dma_map_ops *ops = get_dma_ops(dev); size_t size = SIZE_MAX; if (dma_is_direct(ops)) size = dma_direct_max_mapping_size(dev); else if (ops && ops->max_mapping_size) size = ops->max_mapping_size(dev); return size; } EXPORT_SYMBOL_GPL(dma_max_mapping_size); unsigned long dma_get_merge_boundary(struct device *dev) { const struct dma_map_ops *ops = get_dma_ops(dev); if (!ops || !ops->get_merge_boundary) return 0; /* can't merge */ return ops->get_merge_boundary(dev); } EXPORT_SYMBOL_GPL(dma_get_merge_boundary);