arch/s390/pci/pci_dma.c - linux - Git at Google

 /*
  * Copyright IBM Corp. 2012
  *
  * Author(s):
  *   Jan Glauber <jang@linux.vnet.ibm.com>
  */

 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/export.h>
 #include <linux/iommu-helper.h>
 #include <linux/dma-mapping.h>
 #include <linux/vmalloc.h>
 #include <linux/pci.h>
 #include <asm/pci_dma.h>

 static struct kmem_cache *dma_region_table_cache;
 static struct kmem_cache *dma_page_table_cache;
 static int s390_iommu_strict;

 static int zpci_refresh_global(struct zpci_dev *zdev)
 {
 	return zpci_refresh_trans((u64) zdev->fh << 32, zdev->start_dma,
 				  zdev->iommu_pages * PAGE_SIZE);
 }

 unsigned long *dma_alloc_cpu_table(void)
 {
 	unsigned long *table, *entry;

 	table = kmem_cache_alloc(dma_region_table_cache, GFP_ATOMIC);
 	if (!table)
 		return NULL;

 	for (entry = table; entry < table + ZPCI_TABLE_ENTRIES; entry++)
 		*entry = ZPCI_TABLE_INVALID;
 	return table;
 }

 static void dma_free_cpu_table(void *table)
 {
 	kmem_cache_free(dma_region_table_cache, table);
 }

 static unsigned long *dma_alloc_page_table(void)
 {
 	unsigned long *table, *entry;

 	table = kmem_cache_alloc(dma_page_table_cache, GFP_ATOMIC);
 	if (!table)
 		return NULL;

 	for (entry = table; entry < table + ZPCI_PT_ENTRIES; entry++)
 		*entry = ZPCI_PTE_INVALID;
 	return table;
 }

 static void dma_free_page_table(void *table)
 {
 	kmem_cache_free(dma_page_table_cache, table);
 }

 static unsigned long *dma_get_seg_table_origin(unsigned long *entry)
 {
 	unsigned long *sto;

 	if (reg_entry_isvalid(*entry))
 		sto = get_rt_sto(*entry);
 	else {
 		sto = dma_alloc_cpu_table();
 		if (!sto)
 			return NULL;

 		set_rt_sto(entry, sto);
 		validate_rt_entry(entry);
 		entry_clr_protected(entry);
 	}
 	return sto;
 }

 static unsigned long *dma_get_page_table_origin(unsigned long *entry)
 {
 	unsigned long *pto;

 	if (reg_entry_isvalid(*entry))
 		pto = get_st_pto(*entry);
 	else {
 		pto = dma_alloc_page_table();
 		if (!pto)
 			return NULL;
 		set_st_pto(entry, pto);
 		validate_st_entry(entry);
 		entry_clr_protected(entry);
 	}
 	return pto;
 }

 unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr)
 {
 	unsigned long *sto, *pto;
 	unsigned int rtx, sx, px;

 	rtx = calc_rtx(dma_addr);
 	sto = dma_get_seg_table_origin(&rto[rtx]);
 	if (!sto)
 		return NULL;

 	sx = calc_sx(dma_addr);
 	pto = dma_get_page_table_origin(&sto[sx]);
 	if (!pto)
 		return NULL;

 	px = calc_px(dma_addr);
 	return &pto[px];
 }

 void dma_update_cpu_trans(unsigned long *entry, void *page_addr, int flags)
 {
 	if (flags & ZPCI_PTE_INVALID) {
 		invalidate_pt_entry(entry);
 	} else {
 		set_pt_pfaa(entry, page_addr);
 		validate_pt_entry(entry);
 	}

 	if (flags & ZPCI_TABLE_PROTECTED)
 		entry_set_protected(entry);
 	else
 		entry_clr_protected(entry);
 }

 static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
 			    dma_addr_t dma_addr, size_t size, int flags)
 {
 	unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	u8 *page_addr = (u8 *) (pa & PAGE_MASK);
 	dma_addr_t start_dma_addr = dma_addr;
 	unsigned long irq_flags;
 	unsigned long *entry;
 	int i, rc = 0;

 	if (!nr_pages)
 		return -EINVAL;

 	spin_lock_irqsave(&zdev->dma_table_lock, irq_flags);
 	if (!zdev->dma_table) {
 		rc = -EINVAL;
 		goto no_refresh;
 	}

 	for (i = 0; i < nr_pages; i++) {
 		entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
 		if (!entry) {
 			rc = -ENOMEM;
 			goto undo_cpu_trans;
 		}
 		dma_update_cpu_trans(entry, page_addr, flags);
 		page_addr += PAGE_SIZE;
 		dma_addr += PAGE_SIZE;
 	}

 	/*
 	 * With zdev->tlb_refresh == 0, rpcit is not required to establish new
 	 * translations when previously invalid translation-table entries are
 	 * validated. With lazy unmap, it also is skipped for previously valid
 	 * entries, but a global rpcit is then required before any address can
 	 * be re-used, i.e. after each iommu bitmap wrap-around.
 	 */
 	if (!zdev->tlb_refresh &&
 			(!s390_iommu_strict ||
 			((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)))
 		goto no_refresh;

 	rc = zpci_refresh_trans((u64) zdev->fh << 32, start_dma_addr,
 				nr_pages * PAGE_SIZE);
 undo_cpu_trans:
 	if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
 		flags = ZPCI_PTE_INVALID;
 		while (i-- > 0) {
 			page_addr -= PAGE_SIZE;
 			dma_addr -= PAGE_SIZE;
 			entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
 			if (!entry)
 				break;
 			dma_update_cpu_trans(entry, page_addr, flags);
 		}
 	}

 no_refresh:
 	spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags);
 	return rc;
 }

 void dma_free_seg_table(unsigned long entry)
 {
 	unsigned long *sto = get_rt_sto(entry);
 	int sx;

 	for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++)
 		if (reg_entry_isvalid(sto[sx]))
 			dma_free_page_table(get_st_pto(sto[sx]));

 	dma_free_cpu_table(sto);
 }

 void dma_cleanup_tables(unsigned long *table)
 {
 	int rtx;

 	if (!table)
 		return;

 	for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
 		if (reg_entry_isvalid(table[rtx]))
 			dma_free_seg_table(table[rtx]);

 	dma_free_cpu_table(table);
 }

 static unsigned long __dma_alloc_iommu(struct device *dev,
 				       unsigned long start, int size)
 {
 	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 	unsigned long boundary_size;

 	boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
 			      PAGE_SIZE) >> PAGE_SHIFT;
 	return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
 				start, size, zdev->start_dma >> PAGE_SHIFT,
 				boundary_size, 0);
 }

 static unsigned long dma_alloc_iommu(struct device *dev, int size)
 {
 	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 	unsigned long offset, flags;
 	int wrap = 0;

 	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
 	offset = __dma_alloc_iommu(dev, zdev->next_bit, size);
 	if (offset == -1) {
 		/* wrap-around */
 		offset = __dma_alloc_iommu(dev, 0, size);
 		wrap = 1;
 	}

 	if (offset != -1) {
 		zdev->next_bit = offset + size;
 		if (!zdev->tlb_refresh && !s390_iommu_strict && wrap)
 			/* global flush after wrap-around with lazy unmap */
 			zpci_refresh_global(zdev);
 	}
 	spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
 	return offset;
 }

 static void dma_free_iommu(struct device *dev, unsigned long offset, int size)
 {
 	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 	unsigned long flags;

 	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
 	if (!zdev->iommu_bitmap)
 		goto out;
 	bitmap_clear(zdev->iommu_bitmap, offset, size);
 	/*
 	 * Lazy flush for unmap: need to move next_bit to avoid address re-use
 	 * until wrap-around.
 	 */
 	if (!s390_iommu_strict && offset >= zdev->next_bit)
 		zdev->next_bit = offset + size;
 out:
 	spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
 }

 static inline void zpci_err_dma(unsigned long rc, unsigned long addr)
 {
 	struct {
 		unsigned long rc;
 		unsigned long addr;
 	} __packed data = {rc, addr};

 	zpci_err_hex(&data, sizeof(data));
 }

 static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
 				     unsigned long offset, size_t size,
 				     enum dma_data_direction direction,
 				     unsigned long attrs)
 {
 	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 	unsigned long nr_pages, iommu_page_index;
 	unsigned long pa = page_to_phys(page) + offset;
 	int flags = ZPCI_PTE_VALID;
 	dma_addr_t dma_addr;
 	int ret;

 	/* This rounds up number of pages based on size and offset */
 	nr_pages = iommu_num_pages(pa, size, PAGE_SIZE);
 	iommu_page_index = dma_alloc_iommu(dev, nr_pages);
 	if (iommu_page_index == -1) {
 		ret = -ENOSPC;
 		goto out_err;
 	}

 	/* Use rounded up size */
 	size = nr_pages * PAGE_SIZE;

 	dma_addr = zdev->start_dma + iommu_page_index * PAGE_SIZE;
 	if (dma_addr + size > zdev->end_dma) {
 		ret = -ERANGE;
 		goto out_free;
 	}

 	if (direction == DMA_NONE || direction == DMA_TO_DEVICE)
 		flags |= ZPCI_TABLE_PROTECTED;

 	ret = dma_update_trans(zdev, pa, dma_addr, size, flags);
 	if (ret)
 		goto out_free;

 	atomic64_add(nr_pages, &zdev->mapped_pages);
 	return dma_addr + (offset & ~PAGE_MASK);

 out_free:
 	dma_free_iommu(dev, iommu_page_index, nr_pages);
 out_err:
 	zpci_err("map error:\n");
 	zpci_err_dma(ret, pa);
 	return DMA_ERROR_CODE;
 }

 static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
 				 size_t size, enum dma_data_direction direction,
 				 unsigned long attrs)
 {
 	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 	unsigned long iommu_page_index;
 	int npages, ret;

 	npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
 	dma_addr = dma_addr & PAGE_MASK;
 	ret = dma_update_trans(zdev, 0, dma_addr, npages * PAGE_SIZE,
 			       ZPCI_PTE_INVALID);
 	if (ret) {
 		zpci_err("unmap error:\n");
 		zpci_err_dma(ret, dma_addr);
 		return;
 	}

 	atomic64_add(npages, &zdev->unmapped_pages);
 	iommu_page_index = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
 	dma_free_iommu(dev, iommu_page_index, npages);
 }

 static void *s390_dma_alloc(struct device *dev, size_t size,
 			    dma_addr_t *dma_handle, gfp_t flag,
 			    unsigned long attrs)
 {
 	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 	struct page *page;
 	unsigned long pa;
 	dma_addr_t map;

 	size = PAGE_ALIGN(size);
 	page = alloc_pages(flag, get_order(size));
 	if (!page)
 		return NULL;

 	pa = page_to_phys(page);
 	memset((void *) pa, 0, size);

 	map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, 0);
 	if (dma_mapping_error(dev, map)) {
 		free_pages(pa, get_order(size));
 		return NULL;
 	}

 	atomic64_add(size / PAGE_SIZE, &zdev->allocated_pages);
 	if (dma_handle)
 		*dma_handle = map;
 	return (void *) pa;
 }

 static void s390_dma_free(struct device *dev, size_t size,
 			  void *pa, dma_addr_t dma_handle,
 			  unsigned long attrs)
 {
 	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));

 	size = PAGE_ALIGN(size);
 	atomic64_sub(size / PAGE_SIZE, &zdev->allocated_pages);
 	s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, 0);
 	free_pages((unsigned long) pa, get_order(size));
 }

 static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
 			   int nr_elements, enum dma_data_direction dir,
 			   unsigned long attrs)
 {
 	int mapped_elements = 0;
 	struct scatterlist *s;
 	int i;

 	for_each_sg(sg, s, nr_elements, i) {
 		struct page *page = sg_page(s);
 		s->dma_address = s390_dma_map_pages(dev, page, s->offset,
 						    s->length, dir, 0);
 		if (!dma_mapping_error(dev, s->dma_address)) {
 			s->dma_length = s->length;
 			mapped_elements++;
 		} else
 			goto unmap;
 	}
 out:
 	return mapped_elements;

 unmap:
 	for_each_sg(sg, s, mapped_elements, i) {
 		if (s->dma_address)
 			s390_dma_unmap_pages(dev, s->dma_address, s->dma_length,
 					     dir, 0);
 		s->dma_address = 0;
 		s->dma_length = 0;
 	}
 	mapped_elements = 0;
 	goto out;
 }

 static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 			      int nr_elements, enum dma_data_direction dir,
 			      unsigned long attrs)
 {
 	struct scatterlist *s;
 	int i;

 	for_each_sg(sg, s, nr_elements, i) {
 		s390_dma_unmap_pages(dev, s->dma_address, s->dma_length, dir,
 				     0);
 		s->dma_address = 0;
 		s->dma_length = 0;
 	}
 }

 int zpci_dma_init_device(struct zpci_dev *zdev)
 {
 	int rc;

 	/*
 	 * At this point, if the device is part of an IOMMU domain, this would
 	 * be a strong hint towards a bug in the IOMMU API (common) code and/or
 	 * simultaneous access via IOMMU and DMA API. So let's issue a warning.
 	 */
 	WARN_ON(zdev->s390_domain);

 	spin_lock_init(&zdev->iommu_bitmap_lock);
 	spin_lock_init(&zdev->dma_table_lock);

 	zdev->dma_table = dma_alloc_cpu_table();
 	if (!zdev->dma_table) {
 		rc = -ENOMEM;
 		goto out;
 	}

 	/*
 	 * Restrict the iommu bitmap size to the minimum of the following:
 	 * - main memory size
 	 * - 3-level pagetable address limit minus start_dma offset
 	 * - DMA address range allowed by the hardware (clp query pci fn)
 	 *
 	 * Also set zdev->end_dma to the actual end address of the usable
 	 * range, instead of the theoretical maximum as reported by hardware.
 	 */
 	zdev->start_dma = PAGE_ALIGN(zdev->start_dma);
 	zdev->iommu_size = min3((u64) high_memory,
 				ZPCI_TABLE_SIZE_RT - zdev->start_dma,
 				zdev->end_dma - zdev->start_dma + 1);
 	zdev->end_dma = zdev->start_dma + zdev->iommu_size - 1;
 	zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT;
 	zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8);
 	if (!zdev->iommu_bitmap) {
 		rc = -ENOMEM;
 		goto free_dma_table;
 	}

 	rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 				(u64) zdev->dma_table);
 	if (rc)
 		goto free_bitmap;

 	return 0;
 free_bitmap:
 	vfree(zdev->iommu_bitmap);
 	zdev->iommu_bitmap = NULL;
 free_dma_table:
 	dma_free_cpu_table(zdev->dma_table);
 	zdev->dma_table = NULL;
 out:
 	return rc;
 }

 void zpci_dma_exit_device(struct zpci_dev *zdev)
 {
 	/*
 	 * At this point, if the device is part of an IOMMU domain, this would
 	 * be a strong hint towards a bug in the IOMMU API (common) code and/or
 	 * simultaneous access via IOMMU and DMA API. So let's issue a warning.
 	 */
 	WARN_ON(zdev->s390_domain);

 	zpci_unregister_ioat(zdev, 0);
 	dma_cleanup_tables(zdev->dma_table);
 	zdev->dma_table = NULL;
 	vfree(zdev->iommu_bitmap);
 	zdev->iommu_bitmap = NULL;
 	zdev->next_bit = 0;
 }

 static int __init dma_alloc_cpu_table_caches(void)
 {
 	dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables",
 					ZPCI_TABLE_SIZE, ZPCI_TABLE_ALIGN,
 					0, NULL);
 	if (!dma_region_table_cache)
 		return -ENOMEM;

 	dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables",
 					ZPCI_PT_SIZE, ZPCI_PT_ALIGN,
 					0, NULL);
 	if (!dma_page_table_cache) {
 		kmem_cache_destroy(dma_region_table_cache);
 		return -ENOMEM;
 	}
 	return 0;
 }

 int __init zpci_dma_init(void)
 {
 	return dma_alloc_cpu_table_caches();
 }

 void zpci_dma_exit(void)
 {
 	kmem_cache_destroy(dma_page_table_cache);
 	kmem_cache_destroy(dma_region_table_cache);
 }

 #define PREALLOC_DMA_DEBUG_ENTRIES	(1 << 16)

 static int __init dma_debug_do_init(void)
 {
 	dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 	return 0;
 }
 fs_initcall(dma_debug_do_init);

 struct dma_map_ops s390_pci_dma_ops = {
 	.alloc		= s390_dma_alloc,
 	.free		= s390_dma_free,
 	.map_sg		= s390_dma_map_sg,
 	.unmap_sg	= s390_dma_unmap_sg,
 	.map_page	= s390_dma_map_pages,
 	.unmap_page	= s390_dma_unmap_pages,
 	/* if we support direct DMA this must be conditional */
 	.is_phys	= 0,
 	/* dma_supported is unconditionally true without a callback */
 };
 EXPORT_SYMBOL_GPL(s390_pci_dma_ops);

 static int __init s390_iommu_setup(char *str)
 {
 	if (!strncmp(str, "strict", 6))
 		s390_iommu_strict = 1;
 	return 0;
 }

 __setup("s390_iommu=", s390_iommu_setup);
	/*
	* Copyright IBM Corp. 2012
	*
	* Author(s):
	* Jan Glauber <jang@linux.vnet.ibm.com>
	*/

	#include <linux/kernel.h>
	#include <linux/slab.h>
	#include <linux/export.h>
	#include <linux/iommu-helper.h>
	#include <linux/dma-mapping.h>
	#include <linux/vmalloc.h>
	#include <linux/pci.h>
	#include <asm/pci_dma.h>

	static struct kmem_cache *dma_region_table_cache;
	static struct kmem_cache *dma_page_table_cache;
	static int s390_iommu_strict;

	static int zpci_refresh_global(struct zpci_dev *zdev)
	{
	return zpci_refresh_trans((u64) zdev->fh << 32, zdev->start_dma,
	zdev->iommu_pages * PAGE_SIZE);
	}

	unsigned long *dma_alloc_cpu_table(void)
	{
	unsigned long table, entry;

	table = kmem_cache_alloc(dma_region_table_cache, GFP_ATOMIC);
	if (!table)
	return NULL;

	for (entry = table; entry < table + ZPCI_TABLE_ENTRIES; entry++)
	*entry = ZPCI_TABLE_INVALID;
	return table;
	}

	static void dma_free_cpu_table(void *table)
	{
	kmem_cache_free(dma_region_table_cache, table);
	}

	static unsigned long *dma_alloc_page_table(void)
	{
	unsigned long table, entry;

	table = kmem_cache_alloc(dma_page_table_cache, GFP_ATOMIC);
	if (!table)
	return NULL;

	for (entry = table; entry < table + ZPCI_PT_ENTRIES; entry++)
	*entry = ZPCI_PTE_INVALID;
	return table;
	}

	static void dma_free_page_table(void *table)
	{
	kmem_cache_free(dma_page_table_cache, table);
	}

	static unsigned long dma_get_seg_table_origin(unsigned long entry)
	{
	unsigned long *sto;

	if (reg_entry_isvalid(*entry))
	sto = get_rt_sto(*entry);
	else {
	sto = dma_alloc_cpu_table();
	if (!sto)
	return NULL;

	set_rt_sto(entry, sto);
	validate_rt_entry(entry);
	entry_clr_protected(entry);
	}
	return sto;
	}

	static unsigned long dma_get_page_table_origin(unsigned long entry)
	{
	unsigned long *pto;

	if (reg_entry_isvalid(*entry))
	pto = get_st_pto(*entry);
	else {
	pto = dma_alloc_page_table();
	if (!pto)
	return NULL;
	set_st_pto(entry, pto);
	validate_st_entry(entry);
	entry_clr_protected(entry);
	}
	return pto;
	}

	unsigned long dma_walk_cpu_trans(unsigned long rto, dma_addr_t dma_addr)
	{
	unsigned long sto, pto;
	unsigned int rtx, sx, px;

	rtx = calc_rtx(dma_addr);
	sto = dma_get_seg_table_origin(&rto[rtx]);
	if (!sto)
	return NULL;

	sx = calc_sx(dma_addr);
	pto = dma_get_page_table_origin(&sto[sx]);
	if (!pto)
	return NULL;

	px = calc_px(dma_addr);
	return &pto[px];
	}

	void dma_update_cpu_trans(unsigned long entry, void page_addr, int flags)
	{
	if (flags & ZPCI_PTE_INVALID) {
	invalidate_pt_entry(entry);
	} else {
	set_pt_pfaa(entry, page_addr);
	validate_pt_entry(entry);
	}

	if (flags & ZPCI_TABLE_PROTECTED)
	entry_set_protected(entry);
	else
	entry_clr_protected(entry);
	}

	static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
	dma_addr_t dma_addr, size_t size, int flags)
	{
	unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
	u8 page_addr = (u8 ) (pa & PAGE_MASK);
	dma_addr_t start_dma_addr = dma_addr;
	unsigned long irq_flags;
	unsigned long *entry;
	int i, rc = 0;

	if (!nr_pages)
	return -EINVAL;

	spin_lock_irqsave(&zdev->dma_table_lock, irq_flags);
	if (!zdev->dma_table) {
	rc = -EINVAL;
	goto no_refresh;
	}

	for (i = 0; i < nr_pages; i++) {
	entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
	if (!entry) {
	rc = -ENOMEM;
	goto undo_cpu_trans;
	}
	dma_update_cpu_trans(entry, page_addr, flags);
	page_addr += PAGE_SIZE;
	dma_addr += PAGE_SIZE;
	}

	/*
	* With zdev->tlb_refresh == 0, rpcit is not required to establish new
	* translations when previously invalid translation-table entries are
	* validated. With lazy unmap, it also is skipped for previously valid
	* entries, but a global rpcit is then required before any address can
	* be re-used, i.e. after each iommu bitmap wrap-around.
	*/
	if (!zdev->tlb_refresh &&
	(!s390_iommu_strict \|\|
	((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)))
	goto no_refresh;

	rc = zpci_refresh_trans((u64) zdev->fh << 32, start_dma_addr,
	nr_pages * PAGE_SIZE);
	undo_cpu_trans:
	if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
	flags = ZPCI_PTE_INVALID;
	while (i-- > 0) {
	page_addr -= PAGE_SIZE;
	dma_addr -= PAGE_SIZE;
	entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
	if (!entry)
	break;
	dma_update_cpu_trans(entry, page_addr, flags);
	}
	}

	no_refresh:
	spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags);
	return rc;
	}

	void dma_free_seg_table(unsigned long entry)
	{
	unsigned long *sto = get_rt_sto(entry);
	int sx;

	for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++)
	if (reg_entry_isvalid(sto[sx]))
	dma_free_page_table(get_st_pto(sto[sx]));

	dma_free_cpu_table(sto);
	}

	void dma_cleanup_tables(unsigned long *table)
	{
	int rtx;

	if (!table)
	return;

	for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
	if (reg_entry_isvalid(table[rtx]))
	dma_free_seg_table(table[rtx]);

	dma_free_cpu_table(table);
	}

	static unsigned long __dma_alloc_iommu(struct device *dev,
	unsigned long start, int size)
	{
	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
	unsigned long boundary_size;

	boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
	PAGE_SIZE) >> PAGE_SHIFT;
	return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
	start, size, zdev->start_dma >> PAGE_SHIFT,
	boundary_size, 0);
	}

	static unsigned long dma_alloc_iommu(struct device *dev, int size)
	{
	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
	unsigned long offset, flags;
	int wrap = 0;

	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
	offset = __dma_alloc_iommu(dev, zdev->next_bit, size);
	if (offset == -1) {
	/* wrap-around */
	offset = __dma_alloc_iommu(dev, 0, size);
	wrap = 1;
	}

	if (offset != -1) {
	zdev->next_bit = offset + size;
	if (!zdev->tlb_refresh && !s390_iommu_strict && wrap)
	/* global flush after wrap-around with lazy unmap */
	zpci_refresh_global(zdev);
	}
	spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
	return offset;
	}

	static void dma_free_iommu(struct device *dev, unsigned long offset, int size)
	{
	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
	unsigned long flags;

	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
	if (!zdev->iommu_bitmap)
	goto out;
	bitmap_clear(zdev->iommu_bitmap, offset, size);
	/*
	* Lazy flush for unmap: need to move next_bit to avoid address re-use
	* until wrap-around.
	*/
	if (!s390_iommu_strict && offset >= zdev->next_bit)
	zdev->next_bit = offset + size;
	out:
	spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
	}

	static inline void zpci_err_dma(unsigned long rc, unsigned long addr)
	{
	struct {
	unsigned long rc;
	unsigned long addr;
	} __packed data = {rc, addr};

	zpci_err_hex(&data, sizeof(data));
	}

	static dma_addr_t s390_dma_map_pages(struct device dev, struct page page,
	unsigned long offset, size_t size,
	enum dma_data_direction direction,
	unsigned long attrs)
	{
	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
	unsigned long nr_pages, iommu_page_index;
	unsigned long pa = page_to_phys(page) + offset;
	int flags = ZPCI_PTE_VALID;
	dma_addr_t dma_addr;
	int ret;

	/* This rounds up number of pages based on size and offset */
	nr_pages = iommu_num_pages(pa, size, PAGE_SIZE);
	iommu_page_index = dma_alloc_iommu(dev, nr_pages);
	if (iommu_page_index == -1) {
	ret = -ENOSPC;
	goto out_err;
	}

	/* Use rounded up size */
	size = nr_pages * PAGE_SIZE;

	dma_addr = zdev->start_dma + iommu_page_index * PAGE_SIZE;
	if (dma_addr + size > zdev->end_dma) {
	ret = -ERANGE;
	goto out_free;
	}

	if (direction == DMA_NONE \|\| direction == DMA_TO_DEVICE)
	flags \|= ZPCI_TABLE_PROTECTED;

	ret = dma_update_trans(zdev, pa, dma_addr, size, flags);
	if (ret)
	goto out_free;

	atomic64_add(nr_pages, &zdev->mapped_pages);
	return dma_addr + (offset & ~PAGE_MASK);

	out_free:
	dma_free_iommu(dev, iommu_page_index, nr_pages);
	out_err:
	zpci_err("map error:\n");
	zpci_err_dma(ret, pa);
	return DMA_ERROR_CODE;
	}

	static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
	size_t size, enum dma_data_direction direction,
	unsigned long attrs)
	{
	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
	unsigned long iommu_page_index;
	int npages, ret;

	npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
	dma_addr = dma_addr & PAGE_MASK;
	ret = dma_update_trans(zdev, 0, dma_addr, npages * PAGE_SIZE,
	ZPCI_PTE_INVALID);
	if (ret) {
	zpci_err("unmap error:\n");
	zpci_err_dma(ret, dma_addr);
	return;
	}

	atomic64_add(npages, &zdev->unmapped_pages);
	iommu_page_index = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
	dma_free_iommu(dev, iommu_page_index, npages);
	}

	static void s390_dma_alloc(struct device dev, size_t size,
	dma_addr_t *dma_handle, gfp_t flag,
	unsigned long attrs)
	{
	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
	struct page *page;
	unsigned long pa;
	dma_addr_t map;

	size = PAGE_ALIGN(size);
	page = alloc_pages(flag, get_order(size));
	if (!page)
	return NULL;

	pa = page_to_phys(page);
	memset((void *) pa, 0, size);

	map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, 0);
	if (dma_mapping_error(dev, map)) {
	free_pages(pa, get_order(size));
	return NULL;
	}

	atomic64_add(size / PAGE_SIZE, &zdev->allocated_pages);
	if (dma_handle)
	*dma_handle = map;
	return (void *) pa;
	}

	static void s390_dma_free(struct device *dev, size_t size,
	void *pa, dma_addr_t dma_handle,
	unsigned long attrs)
	{
	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));

	size = PAGE_ALIGN(size);
	atomic64_sub(size / PAGE_SIZE, &zdev->allocated_pages);
	s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, 0);
	free_pages((unsigned long) pa, get_order(size));
	}

	static int s390_dma_map_sg(struct device dev, struct scatterlist sg,
	int nr_elements, enum dma_data_direction dir,
	unsigned long attrs)
	{
	int mapped_elements = 0;
	struct scatterlist *s;
	int i;

	for_each_sg(sg, s, nr_elements, i) {
	struct page *page = sg_page(s);
	s->dma_address = s390_dma_map_pages(dev, page, s->offset,
	s->length, dir, 0);
	if (!dma_mapping_error(dev, s->dma_address)) {
	s->dma_length = s->length;
	mapped_elements++;
	} else
	goto unmap;
	}
	out:
	return mapped_elements;

	unmap:
	for_each_sg(sg, s, mapped_elements, i) {
	if (s->dma_address)
	s390_dma_unmap_pages(dev, s->dma_address, s->dma_length,
	dir, 0);
	s->dma_address = 0;
	s->dma_length = 0;
	}
	mapped_elements = 0;
	goto out;
	}

	static void s390_dma_unmap_sg(struct device dev, struct scatterlist sg,
	int nr_elements, enum dma_data_direction dir,
	unsigned long attrs)
	{
	struct scatterlist *s;
	int i;

	for_each_sg(sg, s, nr_elements, i) {
	s390_dma_unmap_pages(dev, s->dma_address, s->dma_length, dir,
	0);
	s->dma_address = 0;
	s->dma_length = 0;
	}
	}

	int zpci_dma_init_device(struct zpci_dev *zdev)
	{
	int rc;

	/*
	* At this point, if the device is part of an IOMMU domain, this would
	* be a strong hint towards a bug in the IOMMU API (common) code and/or
	* simultaneous access via IOMMU and DMA API. So let's issue a warning.
	*/
	WARN_ON(zdev->s390_domain);

	spin_lock_init(&zdev->iommu_bitmap_lock);
	spin_lock_init(&zdev->dma_table_lock);

	zdev->dma_table = dma_alloc_cpu_table();
	if (!zdev->dma_table) {
	rc = -ENOMEM;
	goto out;
	}

	/*
	* Restrict the iommu bitmap size to the minimum of the following:
	* - main memory size
	* - 3-level pagetable address limit minus start_dma offset
	* - DMA address range allowed by the hardware (clp query pci fn)
	*
	* Also set zdev->end_dma to the actual end address of the usable
	* range, instead of the theoretical maximum as reported by hardware.
	*/
	zdev->start_dma = PAGE_ALIGN(zdev->start_dma);
	zdev->iommu_size = min3((u64) high_memory,
	ZPCI_TABLE_SIZE_RT - zdev->start_dma,
	zdev->end_dma - zdev->start_dma + 1);
	zdev->end_dma = zdev->start_dma + zdev->iommu_size - 1;
	zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT;
	zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8);
	if (!zdev->iommu_bitmap) {
	rc = -ENOMEM;
	goto free_dma_table;
	}

	rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
	(u64) zdev->dma_table);
	if (rc)
	goto free_bitmap;

	return 0;
	free_bitmap:
	vfree(zdev->iommu_bitmap);
	zdev->iommu_bitmap = NULL;
	free_dma_table:
	dma_free_cpu_table(zdev->dma_table);
	zdev->dma_table = NULL;
	out:
	return rc;
	}

	void zpci_dma_exit_device(struct zpci_dev *zdev)
	{
	/*
	* At this point, if the device is part of an IOMMU domain, this would
	* be a strong hint towards a bug in the IOMMU API (common) code and/or
	* simultaneous access via IOMMU and DMA API. So let's issue a warning.
	*/
	WARN_ON(zdev->s390_domain);

	zpci_unregister_ioat(zdev, 0);
	dma_cleanup_tables(zdev->dma_table);
	zdev->dma_table = NULL;
	vfree(zdev->iommu_bitmap);
	zdev->iommu_bitmap = NULL;
	zdev->next_bit = 0;
	}

	static int __init dma_alloc_cpu_table_caches(void)
	{
	dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables",
	ZPCI_TABLE_SIZE, ZPCI_TABLE_ALIGN,
	0, NULL);
	if (!dma_region_table_cache)
	return -ENOMEM;

	dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables",
	ZPCI_PT_SIZE, ZPCI_PT_ALIGN,
	0, NULL);
	if (!dma_page_table_cache) {
	kmem_cache_destroy(dma_region_table_cache);
	return -ENOMEM;
	}
	return 0;
	}

	int __init zpci_dma_init(void)
	{
	return dma_alloc_cpu_table_caches();
	}

	void zpci_dma_exit(void)
	{
	kmem_cache_destroy(dma_page_table_cache);
	kmem_cache_destroy(dma_region_table_cache);
	}

	#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)

	static int __init dma_debug_do_init(void)
	{
	dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
	return 0;
	}
	fs_initcall(dma_debug_do_init);

	struct dma_map_ops s390_pci_dma_ops = {
	.alloc = s390_dma_alloc,
	.free = s390_dma_free,
	.map_sg = s390_dma_map_sg,
	.unmap_sg = s390_dma_unmap_sg,
	.map_page = s390_dma_map_pages,
	.unmap_page = s390_dma_unmap_pages,
	/* if we support direct DMA this must be conditional */
	.is_phys = 0,
	/* dma_supported is unconditionally true without a callback */
	};
	EXPORT_SYMBOL_GPL(s390_pci_dma_ops);

	static int __init s390_iommu_setup(char *str)
	{
	if (!strncmp(str, "strict", 6))
	s390_iommu_strict = 1;
	return 0;
	}

	__setup("s390_iommu=", s390_iommu_setup);