| // 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-mapping.h> |
| |
| struct dma_coherent_mem { |
| void *virt_base; |
| dma_addr_t device_base; |
| unsigned long pfn_base; |
| int size; |
| int flags; |
| unsigned long *bitmap; |
| spinlock_t spinlock; |
| bool use_dev_dma_pfn_offset; |
| }; |
| |
| static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init; |
| |
| static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev) |
| { |
| if (dev && dev->dma_mem) |
| return dev->dma_mem; |
| return NULL; |
| } |
| |
| dma_addr_t dma_get_device_base(struct device *dev, |
| struct dma_coherent_mem *mem) |
| { |
| if (mem->use_dev_dma_pfn_offset) |
| return (mem->pfn_base - dev->dma_pfn_offset) << PAGE_SHIFT; |
| else |
| return mem->device_base; |
| } |
| EXPORT_SYMBOL_GPL(dma_get_device_base); |
| |
| unsigned long dma_get_size(struct dma_coherent_mem *mem) |
| { |
| return mem->size << PAGE_SHIFT; |
| } |
| EXPORT_SYMBOL_GPL(dma_get_size); |
| |
| static int dma_init_coherent_memory( |
| phys_addr_t phys_addr, dma_addr_t device_addr, size_t size, int flags, |
| struct dma_coherent_mem **mem) |
| { |
| struct dma_coherent_mem *dma_mem = NULL; |
| void __iomem *mem_base = NULL; |
| int pages = size >> PAGE_SHIFT; |
| int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long); |
| int ret; |
| |
| if (!size) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| mem_base = memremap(phys_addr, size, MEMREMAP_WC); |
| if (!mem_base) { |
| ret = -EINVAL; |
| goto out; |
| } |
| dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL); |
| if (!dma_mem) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL); |
| if (!dma_mem->bitmap) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| dma_mem->virt_base = mem_base; |
| dma_mem->device_base = device_addr; |
| dma_mem->pfn_base = PFN_DOWN(phys_addr); |
| dma_mem->size = pages; |
| dma_mem->flags = flags; |
| spin_lock_init(&dma_mem->spinlock); |
| |
| *mem = dma_mem; |
| return 0; |
| |
| out: |
| kfree(dma_mem); |
| if (mem_base) |
| memunmap(mem_base); |
| return ret; |
| } |
| |
| static void dma_release_coherent_memory(struct dma_coherent_mem *mem) |
| { |
| if (!mem) |
| return; |
| |
| memunmap(mem->virt_base); |
| kfree(mem->bitmap); |
| kfree(mem); |
| } |
| |
| static int dma_assign_coherent_memory(struct device *dev, |
| struct dma_coherent_mem *mem) |
| { |
| if (!dev) |
| return -ENODEV; |
| |
| if (dev->dma_mem) |
| return -EBUSY; |
| |
| dev->dma_mem = mem; |
| return 0; |
| } |
| |
| int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr, |
| dma_addr_t device_addr, size_t size, int flags) |
| { |
| struct dma_coherent_mem *mem; |
| int ret; |
| |
| ret = dma_init_coherent_memory(phys_addr, device_addr, size, flags, &mem); |
| if (ret) |
| return ret; |
| |
| ret = dma_assign_coherent_memory(dev, mem); |
| if (ret) |
| dma_release_coherent_memory(mem); |
| return ret; |
| } |
| EXPORT_SYMBOL(dma_declare_coherent_memory); |
| |
| void dma_release_declared_memory(struct device *dev) |
| { |
| struct dma_coherent_mem *mem = dev->dma_mem; |
| |
| if (!mem) |
| return; |
| dma_release_coherent_memory(mem); |
| dev->dma_mem = NULL; |
| } |
| EXPORT_SYMBOL(dma_release_declared_memory); |
| |
| void *dma_mark_declared_memory_occupied(struct device *dev, |
| dma_addr_t device_addr, size_t size) |
| { |
| struct dma_coherent_mem *mem = dev->dma_mem; |
| unsigned long flags; |
| int pos, err; |
| |
| size += device_addr & ~PAGE_MASK; |
| |
| if (!mem) |
| return ERR_PTR(-EINVAL); |
| |
| spin_lock_irqsave(&mem->spinlock, flags); |
| pos = PFN_DOWN(device_addr - dma_get_device_base(dev, mem)); |
| err = bitmap_allocate_region(mem->bitmap, pos, get_order(size)); |
| spin_unlock_irqrestore(&mem->spinlock, flags); |
| |
| if (err != 0) |
| return ERR_PTR(err); |
| return mem->virt_base + (pos << PAGE_SHIFT); |
| } |
| EXPORT_SYMBOL(dma_mark_declared_memory_occupied); |
| |
| static void *__dma_alloc_from_coherent(struct dma_coherent_mem *mem, |
| ssize_t size, dma_addr_t *dma_handle) |
| { |
| int order = get_order(size); |
| unsigned long flags; |
| int pageno; |
| void *ret; |
| |
| spin_lock_irqsave(&mem->spinlock, flags); |
| |
| if (unlikely(size > (mem->size << PAGE_SHIFT))) |
| goto err; |
| |
| pageno = bitmap_find_free_region(mem->bitmap, mem->size, order); |
| if (unlikely(pageno < 0)) |
| goto err; |
| |
| /* |
| * Memory was found in the coherent area. |
| */ |
| *dma_handle = mem->device_base + (pageno << PAGE_SHIFT); |
| ret = mem->virt_base + (pageno << PAGE_SHIFT); |
| spin_unlock_irqrestore(&mem->spinlock, flags); |
| memset(ret, 0, size); |
| return ret; |
| err: |
| spin_unlock_irqrestore(&mem->spinlock, flags); |
| return NULL; |
| } |
| |
| /** |
| * 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) |
| { |
| struct dma_coherent_mem *mem = dev_get_coherent_memory(dev); |
| |
| if (!mem) |
| return 0; |
| |
| *ret = __dma_alloc_from_coherent(mem, size, dma_handle); |
| if (*ret) |
| return 1; |
| |
| /* |
| * In the case where the allocation can not be satisfied from the |
| * per-device area, try to fall back to generic memory if the |
| * constraints allow it. |
| */ |
| return mem->flags & DMA_MEMORY_EXCLUSIVE; |
| } |
| EXPORT_SYMBOL(dma_alloc_from_dev_coherent); |
| |
| void *dma_alloc_from_global_coherent(ssize_t size, dma_addr_t *dma_handle) |
| { |
| if (!dma_coherent_default_memory) |
| return NULL; |
| |
| return __dma_alloc_from_coherent(dma_coherent_default_memory, size, |
| dma_handle); |
| } |
| |
| static int __dma_release_from_coherent(struct dma_coherent_mem *mem, |
| int order, void *vaddr) |
| { |
| if (mem && vaddr >= mem->virt_base && vaddr < |
| (mem->virt_base + (mem->size << PAGE_SHIFT))) { |
| int page = (vaddr - mem->virt_base) >> PAGE_SHIFT; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&mem->spinlock, flags); |
| bitmap_release_region(mem->bitmap, page, order); |
| spin_unlock_irqrestore(&mem->spinlock, flags); |
| return 1; |
| } |
| return 0; |
| } |
| |
| /** |
| * 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) |
| { |
| struct dma_coherent_mem *mem = dev_get_coherent_memory(dev); |
| |
| return __dma_release_from_coherent(mem, order, vaddr); |
| } |
| EXPORT_SYMBOL(dma_release_from_dev_coherent); |
| |
| 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); |
| } |
| |
| static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem, |
| struct vm_area_struct *vma, void *vaddr, size_t size, int *ret) |
| { |
| if (mem && vaddr >= mem->virt_base && vaddr + size <= |
| (mem->virt_base + (mem->size << PAGE_SHIFT))) { |
| unsigned long off = vma->vm_pgoff; |
| int start = (vaddr - mem->virt_base) >> PAGE_SHIFT; |
| int user_count = vma_pages(vma); |
| int count = PAGE_ALIGN(size) >> PAGE_SHIFT; |
| |
| *ret = -ENXIO; |
| if (off < count && user_count <= count - off) { |
| unsigned long pfn = mem->pfn_base + start + off; |
| *ret = remap_pfn_range(vma, vma->vm_start, pfn, |
| user_count << PAGE_SHIFT, |
| vma->vm_page_prot); |
| } |
| return 1; |
| } |
| return 0; |
| } |
| |
| /** |
| * 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) |
| { |
| struct dma_coherent_mem *mem = dev_get_coherent_memory(dev); |
| |
| return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret); |
| } |
| EXPORT_SYMBOL(dma_mmap_from_dev_coherent); |
| |
| 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); |
| } |
| |
| /* |
| * 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> |
| |
| static struct reserved_mem *dma_reserved_default_memory __initdata; |
| |
| static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev) |
| { |
| struct dma_coherent_mem *mem = rmem->priv; |
| int ret; |
| |
| if (!mem) { |
| ret = dma_init_coherent_memory(rmem->base, rmem->base, |
| rmem->size, |
| DMA_MEMORY_EXCLUSIVE, &mem); |
| if (ret) { |
| pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n", |
| &rmem->base, (unsigned long)rmem->size / SZ_1M); |
| return ret; |
| } |
| } |
| mem->use_dev_dma_pfn_offset = true; |
| rmem->priv = mem; |
| dma_assign_coherent_memory(dev, mem); |
| return 0; |
| } |
| |
| static void rmem_dma_device_release(struct reserved_mem *rmem, |
| struct device *dev) |
| { |
| if (dev) |
| dev->dma_mem = NULL; |
| } |
| |
| static const struct reserved_mem_ops rmem_dma_ops = { |
| .device_init = rmem_dma_device_init, |
| .device_release = rmem_dma_device_release, |
| }; |
| |
| static int __init rmem_dma_setup(struct reserved_mem *rmem) |
| { |
| unsigned long node = rmem->fdt_node; |
| |
| if (of_get_flat_dt_prop(node, "reusable", NULL)) |
| return -EINVAL; |
| |
| #ifdef CONFIG_ARM |
| if (!of_get_flat_dt_prop(node, "no-map", NULL)) { |
| pr_err("Reserved memory: regions without no-map are not yet supported\n"); |
| return -EINVAL; |
| } |
| |
| if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) { |
| WARN(dma_reserved_default_memory, |
| "Reserved memory: region for default DMA coherent area is redefined\n"); |
| dma_reserved_default_memory = rmem; |
| } |
| #endif |
| |
| rmem->ops = &rmem_dma_ops; |
| pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n", |
| &rmem->base, (unsigned long)rmem->size / SZ_1M); |
| return 0; |
| } |
| |
| static int __init dma_init_reserved_memory(void) |
| { |
| const struct reserved_mem_ops *ops; |
| int ret; |
| |
| if (!dma_reserved_default_memory) |
| return -ENOMEM; |
| |
| ops = dma_reserved_default_memory->ops; |
| |
| /* |
| * We rely on rmem_dma_device_init() does not propagate error of |
| * dma_assign_coherent_memory() for "NULL" device. |
| */ |
| ret = ops->device_init(dma_reserved_default_memory, NULL); |
| |
| if (!ret) { |
| dma_coherent_default_memory = dma_reserved_default_memory->priv; |
| pr_info("DMA: default coherent area is set\n"); |
| } |
| |
| return ret; |
| } |
| |
| core_initcall(dma_init_reserved_memory); |
| |
| RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup); |
| #endif |