drivers/base/dma-removed.c - kernel/msm - Git at Google

 /*
  *
  *  Copyright (c) 2013-2017, The Linux Foundation. All rights reserved.
  *  Copyright (C) 2000-2004 Russell King
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
 #include <linux/bootmem.h>
 #include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/gfp.h>
 #include <linux/errno.h>
 #include <linux/ioport.h>
 #include <linux/list.h>
 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/dma-mapping.h>
 #include <linux/dma-contiguous.h>
 #include <linux/highmem.h>
 #include <linux/memblock.h>
 #include <linux/slab.h>
 #include <linux/iommu.h>
 #include <linux/io.h>
 #include <linux/vmalloc.h>
 #include <linux/sizes.h>
 #include <linux/spinlock.h>
 #include <asm/dma-contiguous.h>
 #include <asm/tlbflush.h>

 struct removed_region {
 	phys_addr_t	base;
 	int		nr_pages;
 	unsigned long	*bitmap;
 	int		fixup;
 	struct mutex	lock;
 };

 #define NO_KERNEL_MAPPING_DUMMY	0x2222

 static int dma_init_removed_memory(phys_addr_t phys_addr, size_t size,
 				struct removed_region **mem)
 {
 	struct removed_region *dma_mem = NULL;
 	int pages = size >> PAGE_SHIFT;
 	int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);

 	dma_mem = kzalloc(sizeof(struct removed_region), GFP_KERNEL);
 	if (!dma_mem)
 		goto out;
 	dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
 	if (!dma_mem->bitmap)
 		goto free1_out;

 	dma_mem->base = phys_addr;
 	dma_mem->nr_pages = pages;
 	mutex_init(&dma_mem->lock);

 	*mem = dma_mem;

 	return 0;

 free1_out:
 	kfree(dma_mem);
 out:
 	return -ENOMEM;
 }

 static int dma_assign_removed_region(struct device *dev,
 					struct removed_region *mem)
 {
 	if (dev->removed_mem)
 		return -EBUSY;

 	dev->removed_mem = mem;
 	return 0;
 }

 static void adapt_iomem_resource(unsigned long base_pfn, unsigned long end_pfn)
 {
 	struct resource *res, *conflict;
 	resource_size_t cstart, cend;

 	res = kzalloc(sizeof(*res), GFP_KERNEL);
 	if (!res)
 		return;

 	res->name  = "System RAM";
 	res->start = __pfn_to_phys(base_pfn);
 	res->end = __pfn_to_phys(end_pfn) - 1;
 	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;

 	conflict = request_resource_conflict(&iomem_resource, res);
 	if (!conflict) {
 		pr_err("Removed memory: no conflict resource found\n");
 		kfree(res);
 		goto done;
 	}

 	cstart = conflict->start;
 	cend = conflict->end;
 	if ((cstart == res->start) && (cend == res->end)) {
 		release_resource(conflict);
 	} else if ((res->start >= cstart) && (res->start <= cend)) {
 		if (res->start == cstart) {
 			adjust_resource(conflict, res->end + 1,
 					cend - res->end);
 		} else if (res->end == cend) {
 			adjust_resource(conflict, cstart,
 					res->start - cstart);
 		} else {
 			adjust_resource(conflict, cstart,
 					res->start - cstart);
 			res->start = res->end + 1;
 			res->end = cend;
 			request_resource(&iomem_resource, res);
 			goto done;
 		}
 	} else {
 		pr_err("Removed memory: incorrect resource conflict start=%llx end=%llx\n",
 				(unsigned long long) conflict->start,
 				(unsigned long long) conflict->end);
 	}

 	kfree(res);
 done:
 	return;
 }

 #ifdef CONFIG_FLATMEM
 static void free_memmap(unsigned long start_pfn, unsigned long end_pfn)
 {
 	struct page *start_pg, *end_pg;
 	unsigned long pg, pgend;

 	start_pfn = ALIGN(start_pfn, pageblock_nr_pages);
 	end_pfn = round_down(end_pfn, pageblock_nr_pages);
 	/*
 	 * Convert start_pfn/end_pfn to a struct page pointer.
 	 */
 	start_pg = pfn_to_page(start_pfn - 1) + 1;
 	end_pg = pfn_to_page(end_pfn - 1) + 1;

 	/*
 	 * Convert to physical addresses, and round start upwards and end
 	 * downwards.
 	 */
 	pg = (unsigned long)PAGE_ALIGN(__pa(start_pg));
 	pgend = (unsigned long)__pa(end_pg) & PAGE_MASK;

 	/*
 	 * If there are free pages between these, free the section of the
 	 * memmap array.
 	 */
 	if (pg < pgend)
 		free_bootmem_late(pg, pgend - pg);
 }
 #else
 static void free_memmap(unsigned long start_pfn, unsigned long end_pfn)
 {
 }
 #endif

 static int _clear_pte(pte_t *pte, pgtable_t token, unsigned long addr,
 			    void *data)
 {
 	pte_clear(&init_mm, addr, pte);
 	return 0;
 }

 static void clear_mapping(unsigned long addr, unsigned long size)
 {
 	apply_to_page_range(&init_mm, addr, size, _clear_pte, NULL);
 	/* ensure ptes are updated */
 	mb();
 	flush_tlb_kernel_range(addr, addr + size);
 }

 static void removed_region_fixup(struct removed_region *dma_mem, int index)
 {
 	unsigned long fixup_size;
 	unsigned long base_pfn;
 	unsigned long flags;

 	if (index > dma_mem->nr_pages)
 		return;

 	/* carve-out */
 	flags = memblock_region_resize_late_begin();
 	memblock_free(dma_mem->base, dma_mem->nr_pages * PAGE_SIZE);
 	memblock_remove(dma_mem->base, index * PAGE_SIZE);
 	memblock_region_resize_late_end(flags);

 	/* clear page-mappings */
 	base_pfn = dma_mem->base >> PAGE_SHIFT;
 	if (!PageHighMem(pfn_to_page(base_pfn))) {
 		clear_mapping((unsigned long) phys_to_virt(dma_mem->base),
 				index * PAGE_SIZE);
 	}

 	/* free page objects */
 	free_memmap(base_pfn, base_pfn + index);

 	/* return remaining area to system */
 	fixup_size = (dma_mem->nr_pages - index) * PAGE_SIZE;
 	free_bootmem_late(dma_mem->base + index * PAGE_SIZE, fixup_size);

 	/*
 	 * release freed resource region so as to show up under iomem resource
 	 * list
 	 */
 	adapt_iomem_resource(base_pfn, base_pfn + index);

 	/* limit the fixup region */
 	dma_mem->nr_pages = index;
 }

 void *removed_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 		    gfp_t gfp, unsigned long attrs)
 {
 	bool no_kernel_mapping = attrs & DMA_ATTR_NO_KERNEL_MAPPING;
 	bool skip_zeroing = attrs & DMA_ATTR_SKIP_ZEROING;
 	int pageno;
 	unsigned long order;
 	void *addr = NULL;
 	struct removed_region *dma_mem = dev->removed_mem;
 	int nbits;
 	unsigned int align;

 	if (!gfpflags_allow_blocking(gfp))
 		return NULL;

 	size = PAGE_ALIGN(size);
 	nbits = size >> PAGE_SHIFT;
 	order = get_order(size);

 	if (order > get_order(SZ_1M))
 		order = get_order(SZ_1M);

 	align = (1 << order) - 1;


 	mutex_lock(&dma_mem->lock);
 	pageno = bitmap_find_next_zero_area(dma_mem->bitmap, dma_mem->nr_pages,
 						0, nbits, align);

 	if (pageno < dma_mem->nr_pages) {
 		phys_addr_t base = dma_mem->base + pageno * PAGE_SIZE;
 		*handle = base;

 		bitmap_set(dma_mem->bitmap, pageno, nbits);

 		if (dma_mem->fixup) {
 			removed_region_fixup(dma_mem, pageno + nbits);
 			dma_mem->fixup = 0;
 		}

 		if (no_kernel_mapping && skip_zeroing) {
 			addr = (void *)NO_KERNEL_MAPPING_DUMMY;
 			goto out;
 		}

 		addr = ioremap(base, size);
 		if (WARN_ON(!addr)) {
 			bitmap_clear(dma_mem->bitmap, pageno, nbits);
 		} else {
 			if (!skip_zeroing)
 				memset_io(addr, 0, size);
 			if (no_kernel_mapping) {
 				iounmap(addr);
 				addr = (void *)NO_KERNEL_MAPPING_DUMMY;
 			}
 			*handle = base;
 		}
 	}

 out:
 	mutex_unlock(&dma_mem->lock);
 	return addr;
 }


 int removed_mmap(struct device *dev, struct vm_area_struct *vma,
 		 void *cpu_addr, dma_addr_t dma_addr, size_t size,
 		 unsigned long attrs)
 {
 	return -ENXIO;
 }

 void removed_free(struct device *dev, size_t size, void *cpu_addr,
 		  dma_addr_t handle, unsigned long attrs)
 {
 	bool no_kernel_mapping = attrs & DMA_ATTR_NO_KERNEL_MAPPING;
 	struct removed_region *dma_mem = dev->removed_mem;

 	size = PAGE_ALIGN(size);
 	if (!no_kernel_mapping)
 		iounmap(cpu_addr);
 	mutex_lock(&dma_mem->lock);
 	bitmap_clear(dma_mem->bitmap, (handle - dma_mem->base) >> PAGE_SHIFT,
 				size >> PAGE_SHIFT);
 	mutex_unlock(&dma_mem->lock);
 }

 static dma_addr_t removed_map_page(struct device *dev, struct page *page,
 			unsigned long offset, size_t size,
 			enum dma_data_direction dir,
 			unsigned long attrs)
 {
 	return ~(dma_addr_t)0;
 }

 static void removed_unmap_page(struct device *dev, dma_addr_t dma_handle,
 		size_t size, enum dma_data_direction dir,
 		unsigned long attrs)
 {
 }

 static int removed_map_sg(struct device *dev, struct scatterlist *sg,
 			int nents, enum dma_data_direction dir,
 			unsigned long attrs)
 {
 	return 0;
 }

 static void removed_unmap_sg(struct device *dev,
 			struct scatterlist *sg, int nents,
 			enum dma_data_direction dir,
 			unsigned long attrs)
 {
 }

 static void removed_sync_single_for_cpu(struct device *dev,
 			dma_addr_t dma_handle, size_t size,
 			enum dma_data_direction dir)
 {
 }

 void removed_sync_single_for_device(struct device *dev,
 			dma_addr_t dma_handle, size_t size,
 			enum dma_data_direction dir)
 {
 }

 void removed_sync_sg_for_cpu(struct device *dev,
 			struct scatterlist *sg, int nents,
 			enum dma_data_direction dir)
 {
 }

 void removed_sync_sg_for_device(struct device *dev,
 			struct scatterlist *sg, int nents,
 			enum dma_data_direction dir)
 {
 }

 void *removed_remap(struct device *dev, void *cpu_addr, dma_addr_t handle,
 			size_t size, unsigned long attrs)
 {
 	return ioremap(handle, size);
 }

 void removed_unremap(struct device *dev, void *remapped_address, size_t size)
 {
 	iounmap(remapped_address);
 }

 const struct dma_map_ops removed_dma_ops = {
 	.alloc			= removed_alloc,
 	.free			= removed_free,
 	.mmap			= removed_mmap,
 	.map_page		= removed_map_page,
 	.unmap_page		= removed_unmap_page,
 	.map_sg			= removed_map_sg,
 	.unmap_sg		= removed_unmap_sg,
 	.sync_single_for_cpu	= removed_sync_single_for_cpu,
 	.sync_single_for_device	= removed_sync_single_for_device,
 	.sync_sg_for_cpu	= removed_sync_sg_for_cpu,
 	.sync_sg_for_device	= removed_sync_sg_for_device,
 	.remap			= removed_remap,
 	.unremap		= removed_unremap,
 };
 EXPORT_SYMBOL(removed_dma_ops);

 #ifdef CONFIG_OF_RESERVED_MEM
 #include <linux/of.h>
 #include <linux/of_fdt.h>
 #include <linux/of_reserved_mem.h>

 static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
 {
 	struct removed_region *mem = rmem->priv;

 	if (!mem && dma_init_removed_memory(rmem->base, rmem->size, &mem)) {
 		pr_info("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
 			&rmem->base, (unsigned long)rmem->size / SZ_1M);
 		return -EINVAL;
 	}
 	mem->fixup = rmem->fixup;
 	set_dma_ops(dev, &removed_dma_ops);
 	rmem->priv = mem;
 	dma_assign_removed_region(dev, mem);
 	return 0;
 }

 static void rmem_dma_device_release(struct reserved_mem *rmem,
 					struct device *dev)
 {
 	dev->dma_mem = NULL;
 }

 static const struct reserved_mem_ops removed_mem_ops = {
 	.device_init    = rmem_dma_device_init,
 	.device_release = rmem_dma_device_release,
 };

 static int __init removed_dma_setup(struct reserved_mem *rmem)
 {
 	unsigned long node = rmem->fdt_node;
 	int nomap, fixup;

 	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
 	fixup = of_get_flat_dt_prop(node, "no-map-fixup", NULL) != NULL;

 	if (nomap && fixup) {
 		pr_err("Removed memory: nomap & nomap-fixup can't co-exist\n");
 		return -EINVAL;
 	}

 	rmem->fixup = fixup;
 	if (rmem->fixup) {
 		/* Architecture specific contiguous memory fixup only for
 		 * no-map-fixup to split mappings
 		 */
 		dma_contiguous_early_fixup(rmem->base, rmem->size);
 	}

 	rmem->ops = &removed_mem_ops;
 	pr_info("Removed memory: created DMA memory pool at %pa, size %ld MiB\n",
 		&rmem->base, (unsigned long)rmem->size / SZ_1M);
 	return 0;
 }
 RESERVEDMEM_OF_DECLARE(dma, "removed-dma-pool", removed_dma_setup);
 #endif
	/*
	*
	* Copyright (c) 2013-2017, The Linux Foundation. All rights reserved.
	* Copyright (C) 2000-2004 Russell King
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/
	#include <linux/bootmem.h>
	#include <linux/module.h>
	#include <linux/mm.h>
	#include <linux/gfp.h>
	#include <linux/errno.h>
	#include <linux/ioport.h>
	#include <linux/list.h>
	#include <linux/init.h>
	#include <linux/device.h>
	#include <linux/dma-mapping.h>
	#include <linux/dma-contiguous.h>
	#include <linux/highmem.h>
	#include <linux/memblock.h>
	#include <linux/slab.h>
	#include <linux/iommu.h>
	#include <linux/io.h>
	#include <linux/vmalloc.h>
	#include <linux/sizes.h>
	#include <linux/spinlock.h>
	#include <asm/dma-contiguous.h>
	#include <asm/tlbflush.h>

	struct removed_region {
	phys_addr_t base;
	int nr_pages;
	unsigned long *bitmap;
	int fixup;
	struct mutex lock;
	};

	#define NO_KERNEL_MAPPING_DUMMY 0x2222

	static int dma_init_removed_memory(phys_addr_t phys_addr, size_t size,
	struct removed_region **mem)
	{
	struct removed_region *dma_mem = NULL;
	int pages = size >> PAGE_SHIFT;
	int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);

	dma_mem = kzalloc(sizeof(struct removed_region), GFP_KERNEL);
	if (!dma_mem)
	goto out;
	dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
	if (!dma_mem->bitmap)
	goto free1_out;

	dma_mem->base = phys_addr;
	dma_mem->nr_pages = pages;
	mutex_init(&dma_mem->lock);

	*mem = dma_mem;

	return 0;

	free1_out:
	kfree(dma_mem);
	out:
	return -ENOMEM;
	}

	static int dma_assign_removed_region(struct device *dev,
	struct removed_region *mem)
	{
	if (dev->removed_mem)
	return -EBUSY;

	dev->removed_mem = mem;
	return 0;
	}

	static void adapt_iomem_resource(unsigned long base_pfn, unsigned long end_pfn)
	{
	struct resource res, conflict;
	resource_size_t cstart, cend;

	res = kzalloc(sizeof(*res), GFP_KERNEL);
	if (!res)
	return;

	res->name = "System RAM";
	res->start = __pfn_to_phys(base_pfn);
	res->end = __pfn_to_phys(end_pfn) - 1;
	res->flags = IORESOURCE_MEM \| IORESOURCE_BUSY;

	conflict = request_resource_conflict(&iomem_resource, res);
	if (!conflict) {
	pr_err("Removed memory: no conflict resource found\n");
	kfree(res);
	goto done;
	}

	cstart = conflict->start;
	cend = conflict->end;
	if ((cstart == res->start) && (cend == res->end)) {
	release_resource(conflict);
	} else if ((res->start >= cstart) && (res->start <= cend)) {
	if (res->start == cstart) {
	adjust_resource(conflict, res->end + 1,
	cend - res->end);
	} else if (res->end == cend) {
	adjust_resource(conflict, cstart,
	res->start - cstart);
	} else {
	adjust_resource(conflict, cstart,
	res->start - cstart);
	res->start = res->end + 1;
	res->end = cend;
	request_resource(&iomem_resource, res);
	goto done;
	}
	} else {
	pr_err("Removed memory: incorrect resource conflict start=%llx end=%llx\n",
	(unsigned long long) conflict->start,
	(unsigned long long) conflict->end);
	}

	kfree(res);
	done:
	return;
	}

	#ifdef CONFIG_FLATMEM
	static void free_memmap(unsigned long start_pfn, unsigned long end_pfn)
	{
	struct page start_pg, end_pg;
	unsigned long pg, pgend;

	start_pfn = ALIGN(start_pfn, pageblock_nr_pages);
	end_pfn = round_down(end_pfn, pageblock_nr_pages);
	/*
	* Convert start_pfn/end_pfn to a struct page pointer.
	*/
	start_pg = pfn_to_page(start_pfn - 1) + 1;
	end_pg = pfn_to_page(end_pfn - 1) + 1;

	/*
	* Convert to physical addresses, and round start upwards and end
	* downwards.
	*/
	pg = (unsigned long)PAGE_ALIGN(__pa(start_pg));
	pgend = (unsigned long)__pa(end_pg) & PAGE_MASK;

	/*
	* If there are free pages between these, free the section of the
	* memmap array.
	*/
	if (pg < pgend)
	free_bootmem_late(pg, pgend - pg);
	}
	#else
	static void free_memmap(unsigned long start_pfn, unsigned long end_pfn)
	{
	}
	#endif

	static int _clear_pte(pte_t *pte, pgtable_t token, unsigned long addr,
	void *data)
	{
	pte_clear(&init_mm, addr, pte);
	return 0;
	}

	static void clear_mapping(unsigned long addr, unsigned long size)
	{
	apply_to_page_range(&init_mm, addr, size, _clear_pte, NULL);
	/* ensure ptes are updated */
	mb();
	flush_tlb_kernel_range(addr, addr + size);
	}

	static void removed_region_fixup(struct removed_region *dma_mem, int index)
	{
	unsigned long fixup_size;
	unsigned long base_pfn;
	unsigned long flags;

	if (index > dma_mem->nr_pages)
	return;

	/* carve-out */
	flags = memblock_region_resize_late_begin();
	memblock_free(dma_mem->base, dma_mem->nr_pages * PAGE_SIZE);
	memblock_remove(dma_mem->base, index * PAGE_SIZE);
	memblock_region_resize_late_end(flags);

	/* clear page-mappings */
	base_pfn = dma_mem->base >> PAGE_SHIFT;
	if (!PageHighMem(pfn_to_page(base_pfn))) {
	clear_mapping((unsigned long) phys_to_virt(dma_mem->base),
	index * PAGE_SIZE);
	}

	/* free page objects */
	free_memmap(base_pfn, base_pfn + index);

	/* return remaining area to system */
	fixup_size = (dma_mem->nr_pages - index) * PAGE_SIZE;
	free_bootmem_late(dma_mem->base + index * PAGE_SIZE, fixup_size);

	/*
	* release freed resource region so as to show up under iomem resource
	* list
	*/
	adapt_iomem_resource(base_pfn, base_pfn + index);

	/* limit the fixup region */
	dma_mem->nr_pages = index;
	}

	void removed_alloc(struct device dev, size_t size, dma_addr_t *handle,
	gfp_t gfp, unsigned long attrs)
	{
	bool no_kernel_mapping = attrs & DMA_ATTR_NO_KERNEL_MAPPING;
	bool skip_zeroing = attrs & DMA_ATTR_SKIP_ZEROING;
	int pageno;
	unsigned long order;
	void *addr = NULL;
	struct removed_region *dma_mem = dev->removed_mem;
	int nbits;
	unsigned int align;

	if (!gfpflags_allow_blocking(gfp))
	return NULL;

	size = PAGE_ALIGN(size);
	nbits = size >> PAGE_SHIFT;
	order = get_order(size);

	if (order > get_order(SZ_1M))
	order = get_order(SZ_1M);

	align = (1 << order) - 1;


	mutex_lock(&dma_mem->lock);
	pageno = bitmap_find_next_zero_area(dma_mem->bitmap, dma_mem->nr_pages,
	0, nbits, align);

	if (pageno < dma_mem->nr_pages) {
	phys_addr_t base = dma_mem->base + pageno * PAGE_SIZE;
	*handle = base;

	bitmap_set(dma_mem->bitmap, pageno, nbits);

	if (dma_mem->fixup) {
	removed_region_fixup(dma_mem, pageno + nbits);
	dma_mem->fixup = 0;
	}

	if (no_kernel_mapping && skip_zeroing) {
	addr = (void *)NO_KERNEL_MAPPING_DUMMY;
	goto out;
	}

	addr = ioremap(base, size);
	if (WARN_ON(!addr)) {
	bitmap_clear(dma_mem->bitmap, pageno, nbits);
	} else {
	if (!skip_zeroing)
	memset_io(addr, 0, size);
	if (no_kernel_mapping) {
	iounmap(addr);
	addr = (void *)NO_KERNEL_MAPPING_DUMMY;
	}
	*handle = base;
	}
	}

	out:
	mutex_unlock(&dma_mem->lock);
	return addr;
	}


	int removed_mmap(struct device dev, struct vm_area_struct vma,
	void *cpu_addr, dma_addr_t dma_addr, size_t size,
	unsigned long attrs)
	{
	return -ENXIO;
	}

	void removed_free(struct device dev, size_t size, void cpu_addr,
	dma_addr_t handle, unsigned long attrs)
	{
	bool no_kernel_mapping = attrs & DMA_ATTR_NO_KERNEL_MAPPING;
	struct removed_region *dma_mem = dev->removed_mem;

	size = PAGE_ALIGN(size);
	if (!no_kernel_mapping)
	iounmap(cpu_addr);
	mutex_lock(&dma_mem->lock);
	bitmap_clear(dma_mem->bitmap, (handle - dma_mem->base) >> PAGE_SHIFT,
	size >> PAGE_SHIFT);
	mutex_unlock(&dma_mem->lock);
	}

	static dma_addr_t removed_map_page(struct device dev, struct page page,
	unsigned long offset, size_t size,
	enum dma_data_direction dir,
	unsigned long attrs)
	{
	return ~(dma_addr_t)0;
	}

	static void removed_unmap_page(struct device *dev, dma_addr_t dma_handle,
	size_t size, enum dma_data_direction dir,
	unsigned long attrs)
	{
	}

	static int removed_map_sg(struct device dev, struct scatterlist sg,
	int nents, enum dma_data_direction dir,
	unsigned long attrs)
	{
	return 0;
	}

	static void removed_unmap_sg(struct device *dev,
	struct scatterlist *sg, int nents,
	enum dma_data_direction dir,
	unsigned long attrs)
	{
	}

	static void removed_sync_single_for_cpu(struct device *dev,
	dma_addr_t dma_handle, size_t size,
	enum dma_data_direction dir)
	{
	}

	void removed_sync_single_for_device(struct device *dev,
	dma_addr_t dma_handle, size_t size,
	enum dma_data_direction dir)
	{
	}

	void removed_sync_sg_for_cpu(struct device *dev,
	struct scatterlist *sg, int nents,
	enum dma_data_direction dir)
	{
	}

	void removed_sync_sg_for_device(struct device *dev,
	struct scatterlist *sg, int nents,
	enum dma_data_direction dir)
	{
	}

	void removed_remap(struct device dev, void *cpu_addr, dma_addr_t handle,
	size_t size, unsigned long attrs)
	{
	return ioremap(handle, size);
	}

	void removed_unremap(struct device dev, void remapped_address, size_t size)
	{
	iounmap(remapped_address);
	}

	const struct dma_map_ops removed_dma_ops = {
	.alloc = removed_alloc,
	.free = removed_free,
	.mmap = removed_mmap,
	.map_page = removed_map_page,
	.unmap_page = removed_unmap_page,
	.map_sg = removed_map_sg,
	.unmap_sg = removed_unmap_sg,
	.sync_single_for_cpu = removed_sync_single_for_cpu,
	.sync_single_for_device = removed_sync_single_for_device,
	.sync_sg_for_cpu = removed_sync_sg_for_cpu,
	.sync_sg_for_device = removed_sync_sg_for_device,
	.remap = removed_remap,
	.unremap = removed_unremap,
	};
	EXPORT_SYMBOL(removed_dma_ops);

	#ifdef CONFIG_OF_RESERVED_MEM
	#include <linux/of.h>
	#include <linux/of_fdt.h>
	#include <linux/of_reserved_mem.h>

	static int rmem_dma_device_init(struct reserved_mem rmem, struct device dev)
	{
	struct removed_region *mem = rmem->priv;

	if (!mem && dma_init_removed_memory(rmem->base, rmem->size, &mem)) {
	pr_info("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
	&rmem->base, (unsigned long)rmem->size / SZ_1M);
	return -EINVAL;
	}
	mem->fixup = rmem->fixup;
	set_dma_ops(dev, &removed_dma_ops);
	rmem->priv = mem;
	dma_assign_removed_region(dev, mem);
	return 0;
	}

	static void rmem_dma_device_release(struct reserved_mem *rmem,
	struct device *dev)
	{
	dev->dma_mem = NULL;
	}

	static const struct reserved_mem_ops removed_mem_ops = {
	.device_init = rmem_dma_device_init,
	.device_release = rmem_dma_device_release,
	};

	static int __init removed_dma_setup(struct reserved_mem *rmem)
	{
	unsigned long node = rmem->fdt_node;
	int nomap, fixup;

	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
	fixup = of_get_flat_dt_prop(node, "no-map-fixup", NULL) != NULL;

	if (nomap && fixup) {
	pr_err("Removed memory: nomap & nomap-fixup can't co-exist\n");
	return -EINVAL;
	}

	rmem->fixup = fixup;
	if (rmem->fixup) {
	/* Architecture specific contiguous memory fixup only for
	* no-map-fixup to split mappings
	*/
	dma_contiguous_early_fixup(rmem->base, rmem->size);
	}

	rmem->ops = &removed_mem_ops;
	pr_info("Removed memory: created DMA memory pool at %pa, size %ld MiB\n",
	&rmem->base, (unsigned long)rmem->size / SZ_1M);
	return 0;
	}
	RESERVEDMEM_OF_DECLARE(dma, "removed-dma-pool", removed_dma_setup);
	#endif