Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 746 insertions, 0 deletions

diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
new file mode 100644
index 0000000000..99209085c7
--- /dev/null
+++ b/arch/s390/pci/pci_dma.c
@@ -0,0 +1,746 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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-map-ops.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 u64 s390_iommu_aperture;
+static u32 s390_iommu_aperture_factor = 1;
+
+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(gfp_t gfp)
+{
+	unsigned long *table, *entry;
+
+	table = kmem_cache_alloc(dma_region_table_cache, gfp);
+	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(gfp_t gfp)
+{
+	unsigned long *table, *entry;
+
+	table = kmem_cache_alloc(dma_page_table_cache, gfp);
+	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 *rtep, gfp_t gfp)
+{
+	unsigned long old_rte, rte;
+	unsigned long *sto;
+
+	rte = READ_ONCE(*rtep);
+	if (reg_entry_isvalid(rte)) {
+		sto = get_rt_sto(rte);
+	} else {
+		sto = dma_alloc_cpu_table(gfp);
+		if (!sto)
+			return NULL;
+
+		set_rt_sto(&rte, virt_to_phys(sto));
+		validate_rt_entry(&rte);
+		entry_clr_protected(&rte);
+
+		old_rte = cmpxchg(rtep, ZPCI_TABLE_INVALID, rte);
+		if (old_rte != ZPCI_TABLE_INVALID) {
+			/* Somone else was faster, use theirs */
+			dma_free_cpu_table(sto);
+			sto = get_rt_sto(old_rte);
+		}
+	}
+	return sto;
+}
+
+static unsigned long *dma_get_page_table_origin(unsigned long *step, gfp_t gfp)
+{
+	unsigned long old_ste, ste;
+	unsigned long *pto;
+
+	ste = READ_ONCE(*step);
+	if (reg_entry_isvalid(ste)) {
+		pto = get_st_pto(ste);
+	} else {
+		pto = dma_alloc_page_table(gfp);
+		if (!pto)
+			return NULL;
+		set_st_pto(&ste, virt_to_phys(pto));
+		validate_st_entry(&ste);
+		entry_clr_protected(&ste);
+
+		old_ste = cmpxchg(step, ZPCI_TABLE_INVALID, ste);
+		if (old_ste != ZPCI_TABLE_INVALID) {
+			/* Somone else was faster, use theirs */
+			dma_free_page_table(pto);
+			pto = get_st_pto(old_ste);
+		}
+	}
+	return pto;
+}
+
+unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr,
+				  gfp_t gfp)
+{
+	unsigned long *sto, *pto;
+	unsigned int rtx, sx, px;
+
+	rtx = calc_rtx(dma_addr);
+	sto = dma_get_seg_table_origin(&rto[rtx], gfp);
+	if (!sto)
+		return NULL;
+
+	sx = calc_sx(dma_addr);
+	pto = dma_get_page_table_origin(&sto[sx], gfp);
+	if (!pto)
+		return NULL;
+
+	px = calc_px(dma_addr);
+	return &pto[px];
+}
+
+void dma_update_cpu_trans(unsigned long *ptep, phys_addr_t page_addr, int flags)
+{
+	unsigned long pte;
+
+	pte = READ_ONCE(*ptep);
+	if (flags & ZPCI_PTE_INVALID) {
+		invalidate_pt_entry(&pte);
+	} else {
+		set_pt_pfaa(&pte, page_addr);
+		validate_pt_entry(&pte);
+	}
+
+	if (flags & ZPCI_TABLE_PROTECTED)
+		entry_set_protected(&pte);
+	else
+		entry_clr_protected(&pte);
+
+	xchg(ptep, pte);
+}
+
+static int __dma_update_trans(struct zpci_dev *zdev, phys_addr_t pa,
+			      dma_addr_t dma_addr, size_t size, int flags)
+{
+	unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	phys_addr_t page_addr = (pa & PAGE_MASK);
+	unsigned long *entry;
+	int i, rc = 0;
+
+	if (!nr_pages)
+		return -EINVAL;
+
+	if (!zdev->dma_table)
+		return -EINVAL;
+
+	for (i = 0; i < nr_pages; i++) {
+		entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr,
+					   GFP_ATOMIC);
+		if (!entry) {
+			rc = -ENOMEM;
+			goto undo_cpu_trans;
+		}
+		dma_update_cpu_trans(entry, page_addr, flags);
+		page_addr += PAGE_SIZE;
+		dma_addr += 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,
+						   GFP_ATOMIC);
+			if (!entry)
+				break;
+			dma_update_cpu_trans(entry, page_addr, flags);
+		}
+	}
+	return rc;
+}
+
+static int __dma_purge_tlb(struct zpci_dev *zdev, dma_addr_t dma_addr,
+			   size_t size, int flags)
+{
+	unsigned long irqflags;
+	int ret;
+
+	/*
+	 * With zdev->tlb_refresh == 0, rpcit is not required to establish new
+	 * translations when previously invalid translation-table entries are
+	 * validated. With lazy unmap, rpcit 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 ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID) {
+		if (!zdev->tlb_refresh)
+			return 0;
+	} else {
+		if (!s390_iommu_strict)
+			return 0;
+	}
+
+	ret = zpci_refresh_trans((u64) zdev->fh << 32, dma_addr,
+				 PAGE_ALIGN(size));
+	if (ret == -ENOMEM && !s390_iommu_strict) {
+		/* enable the hypervisor to free some resources */
+		if (zpci_refresh_global(zdev))
+			goto out;
+
+		spin_lock_irqsave(&zdev->iommu_bitmap_lock, irqflags);
+		bitmap_andnot(zdev->iommu_bitmap, zdev->iommu_bitmap,
+			      zdev->lazy_bitmap, zdev->iommu_pages);
+		bitmap_zero(zdev->lazy_bitmap, zdev->iommu_pages);
+		spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, irqflags);
+		ret = 0;
+	}
+out:
+	return ret;
+}
+
+static int dma_update_trans(struct zpci_dev *zdev, phys_addr_t pa,
+			    dma_addr_t dma_addr, size_t size, int flags)
+{
+	int rc;
+
+	rc = __dma_update_trans(zdev, pa, dma_addr, size, flags);
+	if (rc)
+		return rc;
+
+	rc = __dma_purge_tlb(zdev, dma_addr, size, flags);
+	if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID))
+		__dma_update_trans(zdev, pa, dma_addr, size, ZPCI_PTE_INVALID);
+
+	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));
+
+	return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
+				start, size, zdev->start_dma >> PAGE_SHIFT,
+				dma_get_seg_boundary_nr_pages(dev, PAGE_SHIFT),
+				0);
+}
+
+static dma_addr_t dma_alloc_address(struct device *dev, int size)
+{
+	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
+	unsigned long offset, flags;
+
+	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
+	offset = __dma_alloc_iommu(dev, zdev->next_bit, size);
+	if (offset == -1) {
+		if (!s390_iommu_strict) {
+			/* global flush before DMA addresses are reused */
+			if (zpci_refresh_global(zdev))
+				goto out_error;
+
+			bitmap_andnot(zdev->iommu_bitmap, zdev->iommu_bitmap,
+				      zdev->lazy_bitmap, zdev->iommu_pages);
+			bitmap_zero(zdev->lazy_bitmap, zdev->iommu_pages);
+		}
+		/* wrap-around */
+		offset = __dma_alloc_iommu(dev, 0, size);
+		if (offset == -1)
+			goto out_error;
+	}
+	zdev->next_bit = offset + size;
+	spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
+
+	return zdev->start_dma + offset * PAGE_SIZE;
+
+out_error:
+	spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
+	return DMA_MAPPING_ERROR;
+}
+
+static void dma_free_address(struct device *dev, dma_addr_t dma_addr, int size)
+{
+	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
+	unsigned long flags, offset;
+
+	offset = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
+
+	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
+	if (!zdev->iommu_bitmap)
+		goto out;
+
+	if (s390_iommu_strict)
+		bitmap_clear(zdev->iommu_bitmap, offset, size);
+	else
+		bitmap_set(zdev->lazy_bitmap, 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 pa = page_to_phys(page) + offset;
+	int flags = ZPCI_PTE_VALID;
+	unsigned long nr_pages;
+	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);
+	dma_addr = dma_alloc_address(dev, nr_pages);
+	if (dma_addr == DMA_MAPPING_ERROR) {
+		ret = -ENOSPC;
+		goto out_err;
+	}
+
+	/* Use rounded up size */
+	size = nr_pages * PAGE_SIZE;
+
+	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_address(dev, dma_addr, nr_pages);
+out_err:
+	zpci_err("map error:\n");
+	zpci_err_dma(ret, pa);
+	return DMA_MAPPING_ERROR;
+}
+
+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));
+	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);
+	dma_free_address(dev, dma_addr, 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;
+	phys_addr_t pa;
+	dma_addr_t map;
+
+	size = PAGE_ALIGN(size);
+	page = alloc_pages(flag | __GFP_ZERO, get_order(size));
+	if (!page)
+		return NULL;
+
+	pa = page_to_phys(page);
+	map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, 0);
+	if (dma_mapping_error(dev, map)) {
+		__free_pages(page, get_order(size));
+		return NULL;
+	}
+
+	atomic64_add(size / PAGE_SIZE, &zdev->allocated_pages);
+	if (dma_handle)
+		*dma_handle = map;
+	return phys_to_virt(pa);
+}
+
+static void s390_dma_free(struct device *dev, size_t size,
+			  void *vaddr, 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)vaddr, get_order(size));
+}
+
+/* Map a segment into a contiguous dma address area */
+static int __s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
+			     size_t size, dma_addr_t *handle,
+			     enum dma_data_direction dir)
+{
+	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
+	dma_addr_t dma_addr_base, dma_addr;
+	int flags = ZPCI_PTE_VALID;
+	struct scatterlist *s;
+	phys_addr_t pa = 0;
+	int ret;
+
+	dma_addr_base = dma_alloc_address(dev, nr_pages);
+	if (dma_addr_base == DMA_MAPPING_ERROR)
+		return -ENOMEM;
+
+	dma_addr = dma_addr_base;
+	if (dir == DMA_NONE || dir == DMA_TO_DEVICE)
+		flags |= ZPCI_TABLE_PROTECTED;
+
+	for (s = sg; dma_addr < dma_addr_base + size; s = sg_next(s)) {
+		pa = page_to_phys(sg_page(s));
+		ret = __dma_update_trans(zdev, pa, dma_addr,
+					 s->offset + s->length, flags);
+		if (ret)
+			goto unmap;
+
+		dma_addr += s->offset + s->length;
+	}
+	ret = __dma_purge_tlb(zdev, dma_addr_base, size, flags);
+	if (ret)
+		goto unmap;
+
+	*handle = dma_addr_base;
+	atomic64_add(nr_pages, &zdev->mapped_pages);
+
+	return ret;
+
+unmap:
+	dma_update_trans(zdev, 0, dma_addr_base, dma_addr - dma_addr_base,
+			 ZPCI_PTE_INVALID);
+	dma_free_address(dev, dma_addr_base, nr_pages);
+	zpci_err("map error:\n");
+	zpci_err_dma(ret, pa);
+	return ret;
+}
+
+static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
+			   int nr_elements, enum dma_data_direction dir,
+			   unsigned long attrs)
+{
+	struct scatterlist *s = sg, *start = sg, *dma = sg;
+	unsigned int max = dma_get_max_seg_size(dev);
+	unsigned int size = s->offset + s->length;
+	unsigned int offset = s->offset;
+	int count = 0, i, ret;
+
+	for (i = 1; i < nr_elements; i++) {
+		s = sg_next(s);
+
+		s->dma_length = 0;
+
+		if (s->offset || (size & ~PAGE_MASK) ||
+		    size + s->length > max) {
+			ret = __s390_dma_map_sg(dev, start, size,
+						&dma->dma_address, dir);
+			if (ret)
+				goto unmap;
+
+			dma->dma_address += offset;
+			dma->dma_length = size - offset;
+
+			size = offset = s->offset;
+			start = s;
+			dma = sg_next(dma);
+			count++;
+		}
+		size += s->length;
+	}
+	ret = __s390_dma_map_sg(dev, start, size, &dma->dma_address, dir);
+	if (ret)
+		goto unmap;
+
+	dma->dma_address += offset;
+	dma->dma_length = size - offset;
+
+	return count + 1;
+unmap:
+	for_each_sg(sg, s, count, i)
+		s390_dma_unmap_pages(dev, sg_dma_address(s), sg_dma_len(s),
+				     dir, attrs);
+
+	return ret;
+}
+
+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) {
+		if (s->dma_length)
+			s390_dma_unmap_pages(dev, s->dma_address, s->dma_length,
+					     dir, attrs);
+		s->dma_address = 0;
+		s->dma_length = 0;
+	}
+}
+
+static unsigned long *bitmap_vzalloc(size_t bits, gfp_t flags)
+{
+	size_t n = BITS_TO_LONGS(bits);
+	size_t bytes;
+
+	if (unlikely(check_mul_overflow(n, sizeof(unsigned long), &bytes)))
+		return NULL;
+
+	return vzalloc(bytes);
+}
+	
+int zpci_dma_init_device(struct zpci_dev *zdev)
+{
+	u8 status;
+	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);
+
+	zdev->dma_table = dma_alloc_cpu_table(GFP_KERNEL);
+	if (!zdev->dma_table) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	/*
+	 * Restrict the iommu bitmap size to the minimum of the following:
+	 * - s390_iommu_aperture which defaults to high_memory
+	 * - 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.
+	 *
+	 * This limits the number of concurrently usable DMA mappings since
+	 * for each DMA mapped memory address we need a DMA address including
+	 * extra DMA addresses for multiple mappings of the same memory address.
+	 */
+	zdev->start_dma = PAGE_ALIGN(zdev->start_dma);
+	zdev->iommu_size = min3(s390_iommu_aperture,
+				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 = bitmap_vzalloc(zdev->iommu_pages, GFP_KERNEL);
+	if (!zdev->iommu_bitmap) {
+		rc = -ENOMEM;
+		goto free_dma_table;
+	}
+	if (!s390_iommu_strict) {
+		zdev->lazy_bitmap = bitmap_vzalloc(zdev->iommu_pages, GFP_KERNEL);
+		if (!zdev->lazy_bitmap) {
+			rc = -ENOMEM;
+			goto free_bitmap;
+		}
+
+	}
+	if (zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
+			       virt_to_phys(zdev->dma_table), &status)) {
+		rc = -EIO;
+		goto free_bitmap;
+	}
+
+	return 0;
+free_bitmap:
+	vfree(zdev->iommu_bitmap);
+	zdev->iommu_bitmap = NULL;
+	vfree(zdev->lazy_bitmap);
+	zdev->lazy_bitmap = NULL;
+free_dma_table:
+	dma_free_cpu_table(zdev->dma_table);
+	zdev->dma_table = NULL;
+out:
+	return rc;
+}
+
+int zpci_dma_exit_device(struct zpci_dev *zdev)
+{
+	int cc = 0;
+
+	/*
+	 * 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);
+	if (zdev_enabled(zdev))
+		cc = zpci_unregister_ioat(zdev, 0);
+	/*
+	 * cc == 3 indicates the function is gone already. This can happen
+	 * if the function was deconfigured/disabled suddenly and we have not
+	 * received a new handle yet.
+	 */
+	if (cc && cc != 3)
+		return -EIO;
+
+	dma_cleanup_tables(zdev->dma_table);
+	zdev->dma_table = NULL;
+	vfree(zdev->iommu_bitmap);
+	zdev->iommu_bitmap = NULL;
+	vfree(zdev->lazy_bitmap);
+	zdev->lazy_bitmap = NULL;
+	zdev->next_bit = 0;
+	return 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)
+{
+	s390_iommu_aperture = (u64)virt_to_phys(high_memory);
+	if (!s390_iommu_aperture_factor)
+		s390_iommu_aperture = ULONG_MAX;
+	else
+		s390_iommu_aperture *= s390_iommu_aperture_factor;
+
+	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);
+}
+
+const 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,
+	.mmap		= dma_common_mmap,
+	.get_sgtable	= dma_common_get_sgtable,
+	.alloc_pages	= dma_common_alloc_pages,
+	.free_pages	= dma_common_free_pages,
+	/* dma_supported is unconditionally true without a callback */
+};
+EXPORT_SYMBOL_GPL(s390_pci_dma_ops);
+
+static int __init s390_iommu_setup(char *str)
+{
+	if (!strcmp(str, "strict"))
+		s390_iommu_strict = 1;
+	return 1;
+}
+
+__setup("s390_iommu=", s390_iommu_setup);
+
+static int __init s390_iommu_aperture_setup(char *str)
+{
+	if (kstrtou32(str, 10, &s390_iommu_aperture_factor))
+		s390_iommu_aperture_factor = 1;
+	return 1;
+}
+
+__setup("s390_iommu_aperture=", s390_iommu_aperture_setup);