// 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;	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;} static inline 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;} static int dma_init_coherent_memory(phys_addr_t phys_addr,		dma_addr_t device_addr, size_t size,		struct dma_coherent_mem **mem){	struct dma_coherent_mem *dma_mem = NULL;	void *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;	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){	struct dma_coherent_mem *mem;	int ret; 	ret = dma_init_coherent_memory(phys_addr, device_addr, size, &mem);	if (ret)		return ret; 	ret = dma_assign_coherent_memory(dev, mem);	if (ret)		dma_release_coherent_memory(mem);	return ret;} static void *__dma_alloc_from_coherent(struct device *dev,				       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 > ((dma_addr_t)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 = dma_get_device_base(dev, mem) +			((dma_addr_t)pageno << PAGE_SHIFT);	ret = mem->virt_base + ((dma_addr_t)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(dev, mem, size, dma_handle);	return 1;} 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);} 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 + ((dma_addr_t)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);} 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 + ((dma_addr_t)mem->size << PAGE_SHIFT))) {		unsigned long off = vma->vm_pgoff;		int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;		unsigned long 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);} 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, &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