// SPDX-License-Identifier: GPL-2.0 /* * Coherent per-device memory handling. * Borrowed from i386 */ #include <linux/io.h> #include <linux/slab.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/dma-direct.h> #include <linux/dma-map-ops.h> struct dma_coherent_mem { … }; static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev) { … } static inline dma_addr_t dma_get_device_base(struct device *dev, struct dma_coherent_mem * mem) { … } static struct dma_coherent_mem *dma_init_coherent_memory(phys_addr_t phys_addr, dma_addr_t device_addr, size_t size, bool use_dma_pfn_offset) { … } static void _dma_release_coherent_memory(struct dma_coherent_mem *mem) { … } static int dma_assign_coherent_memory(struct device *dev, struct dma_coherent_mem *mem) { … } /* * Declare a region of memory to be handed out by dma_alloc_coherent() when it * is asked for coherent memory for this device. This shall only be used * from platform code, usually based on the device tree description. * * phys_addr is the CPU physical address to which the memory is currently * assigned (this will be ioremapped so the CPU can access the region). * * device_addr is the DMA address the device needs to be programmed with to * actually address this memory (this will be handed out as the dma_addr_t in * dma_alloc_coherent()). * * size is the size of the area (must be a multiple of PAGE_SIZE). * * As a simplification for the platforms, only *one* such region of memory may * be declared per device. */ int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr, dma_addr_t device_addr, size_t size) { … } void dma_release_coherent_memory(struct device *dev) { … } static void *__dma_alloc_from_coherent(struct device *dev, struct dma_coherent_mem *mem, ssize_t size, dma_addr_t *dma_handle) { … } /** * dma_alloc_from_dev_coherent() - allocate memory from device coherent pool * @dev: device from which we allocate memory * @size: size of requested memory area * @dma_handle: This will be filled with the correct dma handle * @ret: This pointer will be filled with the virtual address * to allocated area. * * This function should be only called from per-arch dma_alloc_coherent() * to support allocation from per-device coherent memory pools. * * Returns 0 if dma_alloc_coherent should continue with allocating from * generic memory areas, or !0 if dma_alloc_coherent should return @ret. */ int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size, dma_addr_t *dma_handle, void **ret) { … } static int __dma_release_from_coherent(struct dma_coherent_mem *mem, int order, void *vaddr) { … } /** * dma_release_from_dev_coherent() - free memory to device coherent memory pool * @dev: device from which the memory was allocated * @order: the order of pages allocated * @vaddr: virtual address of allocated pages * * This checks whether the memory was allocated from the per-device * coherent memory pool and if so, releases that memory. * * Returns 1 if we correctly released the memory, or 0 if the caller should * proceed with releasing memory from generic pools. */ int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr) { … } static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem, struct vm_area_struct *vma, void *vaddr, size_t size, int *ret) { … } /** * dma_mmap_from_dev_coherent() - mmap memory from the device coherent pool * @dev: device from which the memory was allocated * @vma: vm_area for the userspace memory * @vaddr: cpu address returned by dma_alloc_from_dev_coherent * @size: size of the memory buffer allocated * @ret: result from remap_pfn_range() * * This checks whether the memory was allocated from the per-device * coherent memory pool and if so, maps that memory to the provided vma. * * Returns 1 if @vaddr belongs to the device coherent pool and the caller * should return @ret, or 0 if they should proceed with mapping memory from * generic areas. */ int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma, void *vaddr, size_t size, int *ret) { … } #ifdef CONFIG_DMA_GLOBAL_POOL static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init; void *dma_alloc_from_global_coherent(struct device *dev, ssize_t size, dma_addr_t *dma_handle) { if (!dma_coherent_default_memory) return NULL; return __dma_alloc_from_coherent(dev, dma_coherent_default_memory, size, dma_handle); } int dma_release_from_global_coherent(int order, void *vaddr) { if (!dma_coherent_default_memory) return 0; return __dma_release_from_coherent(dma_coherent_default_memory, order, vaddr); } int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr, size_t size, int *ret) { if (!dma_coherent_default_memory) return 0; return __dma_mmap_from_coherent(dma_coherent_default_memory, vma, vaddr, size, ret); } int dma_init_global_coherent(phys_addr_t phys_addr, size_t size) { struct dma_coherent_mem *mem; mem = dma_init_coherent_memory(phys_addr, phys_addr, size, true); if (IS_ERR(mem)) return PTR_ERR(mem); dma_coherent_default_memory = mem; pr_info("DMA: default coherent area is set\n"); return 0; } #endif /* CONFIG_DMA_GLOBAL_POOL */ /* * Support for reserved memory regions defined in device tree */ #ifdef CONFIG_OF_RESERVED_MEM #include <linux/of.h> #include <linux/of_fdt.h> #include <linux/of_reserved_mem.h> #ifdef CONFIG_DMA_GLOBAL_POOL static struct reserved_mem *dma_reserved_default_memory __initdata; #endif static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev) { … } static void rmem_dma_device_release(struct reserved_mem *rmem, struct device *dev) { … } static const struct reserved_mem_ops rmem_dma_ops = …; static int __init rmem_dma_setup(struct reserved_mem *rmem) { … } #ifdef CONFIG_DMA_GLOBAL_POOL static int __init dma_init_reserved_memory(void) { if (!dma_reserved_default_memory) return -ENOMEM; return dma_init_global_coherent(dma_reserved_default_memory->base, dma_reserved_default_memory->size); } core_initcall(dma_init_reserved_memory); #endif /* CONFIG_DMA_GLOBAL_POOL */ RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup); #endif
Codebase Browser
linux