// 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 {	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 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 phys_to_dma(dev, PFN_PHYS(mem->pfn_base));	return mem->device_base;} 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){	struct dma_coherent_mem *dma_mem;	int pages = size >> PAGE_SHIFT;	void *mem_base; 	if (!size)		return ERR_PTR(-EINVAL); 	mem_base = memremap(phys_addr, size, MEMREMAP_WC);	if (!mem_base)		return ERR_PTR(-EINVAL); 	dma_mem = kzalloc_obj(struct dma_coherent_mem);	if (!dma_mem)		goto out_unmap_membase;	dma_mem->bitmap = bitmap_zalloc(pages, GFP_KERNEL);	if (!dma_mem->bitmap)		goto out_free_dma_mem; 	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->use_dev_dma_pfn_offset = use_dma_pfn_offset;	spin_lock_init(&dma_mem->spinlock); 	return dma_mem; out_free_dma_mem:	kfree(dma_mem);out_unmap_membase:	memunmap(mem_base);	pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %zu KiB\n",		&phys_addr, size / SZ_1K);	return ERR_PTR(-ENOMEM);} static void _dma_release_coherent_memory(struct dma_coherent_mem *mem){	if (!mem)		return; 	memunmap(mem->virt_base);	bitmap_free(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;} /* * 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){	struct dma_coherent_mem *mem;	int ret; 	mem = dma_init_coherent_memory(phys_addr, device_addr, size, false);	if (IS_ERR(mem))		return PTR_ERR(mem); 	ret = dma_assign_coherent_memory(dev, mem);	if (ret)		_dma_release_coherent_memory(mem);	return ret;} void dma_release_coherent_memory(struct device *dev){	if (dev) {		_dma_release_coherent_memory(dev->dma_mem);		dev->dma_mem = NULL;	}} 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;} 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);} 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))) {		const pgoff_t pgoff_start = vma_start_pgoff(vma);		const pgoff_t pgoff_end = vma_end_pgoff(vma);		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 (pgoff_start < count && pgoff_end <= count) {			unsigned long pfn = mem->pfn_base + start + pgoff_start;			*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);} #ifdef CONFIG_DMA_GLOBAL_POOLstatic 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_POOLstatic phys_addr_t dma_reserved_default_memory_base __initdata;static phys_addr_t dma_reserved_default_memory_size __initdata;#endif static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev){	struct dma_coherent_mem *mem = rmem->priv; 	if (!mem) {		mem = dma_init_coherent_memory(rmem->base, rmem->base,					       rmem->size, true);		if (IS_ERR(mem))			return PTR_ERR(mem);		rmem->priv = mem;	} 	/* Warn if the device potentially can't use the reserved memory */	if (mem->device_base + rmem->size - 1 >	    min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit))		dev_warn(dev, "reserved memory is beyond device's set DMA address range\n"); 	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 int __init rmem_dma_setup(unsigned long node, struct reserved_mem *rmem){	if (of_get_flat_dt_prop(node, "reusable", NULL))		return -ENODEV; #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;	}#endif #ifdef CONFIG_DMA_GLOBAL_POOL	if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) {		WARN(dma_reserved_default_memory_size,		     "Reserved memory: region for default DMA coherent area is redefined\n");		dma_reserved_default_memory_base = rmem->base;		dma_reserved_default_memory_size = rmem->size;	}#endif 	pr_info("Reserved memory: created DMA memory pool at %pa, size %llu KiB\n",		&rmem->base, (unsigned long long)(rmem->size / SZ_1K));	return 0;} #ifdef CONFIG_DMA_GLOBAL_POOLstatic int __init dma_init_reserved_memory(void){	if (!dma_reserved_default_memory_size)		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 */ static const struct reserved_mem_ops rmem_dma_ops = {	.node_init	= rmem_dma_setup,	.device_init	= rmem_dma_device_init,	.device_release	= rmem_dma_device_release,}; RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", &rmem_dma_ops);#endif