1 files changed, 768 insertions, 0 deletions

diff --git a/arch/sparc/kernel/iommu.c b/arch/sparc/kernel/iommu.c
new file mode 100644
index 000000000..a034f571d
--- /dev/null
+++ b/arch/sparc/kernel/iommu.c
@@ -0,0 +1,768 @@
+// SPDX-License-Identifier: GPL-2.0
+/* iommu.c: Generic sparc64 IOMMU support.
+ *
+ * Copyright (C) 1999, 2007, 2008 David S. Miller (davem@davemloft.net)
+ * Copyright (C) 1999, 2000 Jakub Jelinek (jakub@redhat.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dma-map-ops.h>
+#include <linux/errno.h>
+#include <linux/iommu-helper.h>
+#include <linux/bitmap.h>
+#include <asm/iommu-common.h>
+
+#ifdef CONFIG_PCI
+#include <linux/pci.h>
+#endif
+
+#include <asm/iommu.h>
+
+#include "iommu_common.h"
+#include "kernel.h"
+
+#define STC_CTXMATCH_ADDR(STC, CTX)	\
+	((STC)->strbuf_ctxmatch_base + ((CTX) << 3))
+#define STC_FLUSHFLAG_INIT(STC) \
+	(*((STC)->strbuf_flushflag) = 0UL)
+#define STC_FLUSHFLAG_SET(STC) \
+	(*((STC)->strbuf_flushflag) != 0UL)
+
+#define iommu_read(__reg) \
+({	u64 __ret; \
+	__asm__ __volatile__("ldxa [%1] %2, %0" \
+			     : "=r" (__ret) \
+			     : "r" (__reg), "i" (ASI_PHYS_BYPASS_EC_E) \
+			     : "memory"); \
+	__ret; \
+})
+#define iommu_write(__reg, __val) \
+	__asm__ __volatile__("stxa %0, [%1] %2" \
+			     : /* no outputs */ \
+			     : "r" (__val), "r" (__reg), \
+			       "i" (ASI_PHYS_BYPASS_EC_E))
+
+/* Must be invoked under the IOMMU lock. */
+static void iommu_flushall(struct iommu_map_table *iommu_map_table)
+{
+	struct iommu *iommu = container_of(iommu_map_table, struct iommu, tbl);
+	if (iommu->iommu_flushinv) {
+		iommu_write(iommu->iommu_flushinv, ~(u64)0);
+	} else {
+		unsigned long tag;
+		int entry;
+
+		tag = iommu->iommu_tags;
+		for (entry = 0; entry < 16; entry++) {
+			iommu_write(tag, 0);
+			tag += 8;
+		}
+
+		/* Ensure completion of previous PIO writes. */
+		(void) iommu_read(iommu->write_complete_reg);
+	}
+}
+
+#define IOPTE_CONSISTENT(CTX) \
+	(IOPTE_VALID | IOPTE_CACHE | \
+	 (((CTX) << 47) & IOPTE_CONTEXT))
+
+#define IOPTE_STREAMING(CTX) \
+	(IOPTE_CONSISTENT(CTX) | IOPTE_STBUF)
+
+/* Existing mappings are never marked invalid, instead they
+ * are pointed to a dummy page.
+ */
+#define IOPTE_IS_DUMMY(iommu, iopte)	\
+	((iopte_val(*iopte) & IOPTE_PAGE) == (iommu)->dummy_page_pa)
+
+static inline void iopte_make_dummy(struct iommu *iommu, iopte_t *iopte)
+{
+	unsigned long val = iopte_val(*iopte);
+
+	val &= ~IOPTE_PAGE;
+	val |= iommu->dummy_page_pa;
+
+	iopte_val(*iopte) = val;
+}
+
+int iommu_table_init(struct iommu *iommu, int tsbsize,
+		     u32 dma_offset, u32 dma_addr_mask,
+		     int numa_node)
+{
+	unsigned long i, order, sz, num_tsb_entries;
+	struct page *page;
+
+	num_tsb_entries = tsbsize / sizeof(iopte_t);
+
+	/* Setup initial software IOMMU state. */
+	spin_lock_init(&iommu->lock);
+	iommu->ctx_lowest_free = 1;
+	iommu->tbl.table_map_base = dma_offset;
+	iommu->dma_addr_mask = dma_addr_mask;
+
+	/* Allocate and initialize the free area map.  */
+	sz = num_tsb_entries / 8;
+	sz = (sz + 7UL) & ~7UL;
+	iommu->tbl.map = kzalloc_node(sz, GFP_KERNEL, numa_node);
+	if (!iommu->tbl.map)
+		return -ENOMEM;
+
+	iommu_tbl_pool_init(&iommu->tbl, num_tsb_entries, IO_PAGE_SHIFT,
+			    (tlb_type != hypervisor ? iommu_flushall : NULL),
+			    false, 1, false);
+
+	/* Allocate and initialize the dummy page which we
+	 * set inactive IO PTEs to point to.
+	 */
+	page = alloc_pages_node(numa_node, GFP_KERNEL, 0);
+	if (!page) {
+		printk(KERN_ERR "IOMMU: Error, gfp(dummy_page) failed.\n");
+		goto out_free_map;
+	}
+	iommu->dummy_page = (unsigned long) page_address(page);
+	memset((void *)iommu->dummy_page, 0, PAGE_SIZE);
+	iommu->dummy_page_pa = (unsigned long) __pa(iommu->dummy_page);
+
+	/* Now allocate and setup the IOMMU page table itself.  */
+	order = get_order(tsbsize);
+	page = alloc_pages_node(numa_node, GFP_KERNEL, order);
+	if (!page) {
+		printk(KERN_ERR "IOMMU: Error, gfp(tsb) failed.\n");
+		goto out_free_dummy_page;
+	}
+	iommu->page_table = (iopte_t *)page_address(page);
+
+	for (i = 0; i < num_tsb_entries; i++)
+		iopte_make_dummy(iommu, &iommu->page_table[i]);
+
+	return 0;
+
+out_free_dummy_page:
+	free_page(iommu->dummy_page);
+	iommu->dummy_page = 0UL;
+
+out_free_map:
+	kfree(iommu->tbl.map);
+	iommu->tbl.map = NULL;
+
+	return -ENOMEM;
+}
+
+static inline iopte_t *alloc_npages(struct device *dev,
+				    struct iommu *iommu,
+				    unsigned long npages)
+{
+	unsigned long entry;
+
+	entry = iommu_tbl_range_alloc(dev, &iommu->tbl, npages, NULL,
+				      (unsigned long)(-1), 0);
+	if (unlikely(entry == IOMMU_ERROR_CODE))
+		return NULL;
+
+	return iommu->page_table + entry;
+}
+
+static int iommu_alloc_ctx(struct iommu *iommu)
+{
+	int lowest = iommu->ctx_lowest_free;
+	int n = find_next_zero_bit(iommu->ctx_bitmap, IOMMU_NUM_CTXS, lowest);
+
+	if (unlikely(n == IOMMU_NUM_CTXS)) {
+		n = find_next_zero_bit(iommu->ctx_bitmap, lowest, 1);
+		if (unlikely(n == lowest)) {
+			printk(KERN_WARNING "IOMMU: Ran out of contexts.\n");
+			n = 0;
+		}
+	}
+	if (n)
+		__set_bit(n, iommu->ctx_bitmap);
+
+	return n;
+}
+
+static inline void iommu_free_ctx(struct iommu *iommu, int ctx)
+{
+	if (likely(ctx)) {
+		__clear_bit(ctx, iommu->ctx_bitmap);
+		if (ctx < iommu->ctx_lowest_free)
+			iommu->ctx_lowest_free = ctx;
+	}
+}
+
+static void *dma_4u_alloc_coherent(struct device *dev, size_t size,
+				   dma_addr_t *dma_addrp, gfp_t gfp,
+				   unsigned long attrs)
+{
+	unsigned long order, first_page;
+	struct iommu *iommu;
+	struct page *page;
+	int npages, nid;
+	iopte_t *iopte;
+	void *ret;
+
+	size = IO_PAGE_ALIGN(size);
+	order = get_order(size);
+	if (order >= 10)
+		return NULL;
+
+	nid = dev->archdata.numa_node;
+	page = alloc_pages_node(nid, gfp, order);
+	if (unlikely(!page))
+		return NULL;
+
+	first_page = (unsigned long) page_address(page);
+	memset((char *)first_page, 0, PAGE_SIZE << order);
+
+	iommu = dev->archdata.iommu;
+
+	iopte = alloc_npages(dev, iommu, size >> IO_PAGE_SHIFT);
+
+	if (unlikely(iopte == NULL)) {
+		free_pages(first_page, order);
+		return NULL;
+	}
+
+	*dma_addrp = (iommu->tbl.table_map_base +
+		      ((iopte - iommu->page_table) << IO_PAGE_SHIFT));
+	ret = (void *) first_page;
+	npages = size >> IO_PAGE_SHIFT;
+	first_page = __pa(first_page);
+	while (npages--) {
+		iopte_val(*iopte) = (IOPTE_CONSISTENT(0UL) |
+				     IOPTE_WRITE |
+				     (first_page & IOPTE_PAGE));
+		iopte++;
+		first_page += IO_PAGE_SIZE;
+	}
+
+	return ret;
+}
+
+static void dma_4u_free_coherent(struct device *dev, size_t size,
+				 void *cpu, dma_addr_t dvma,
+				 unsigned long attrs)
+{
+	struct iommu *iommu;
+	unsigned long order, npages;
+
+	npages = IO_PAGE_ALIGN(size) >> IO_PAGE_SHIFT;
+	iommu = dev->archdata.iommu;
+
+	iommu_tbl_range_free(&iommu->tbl, dvma, npages, IOMMU_ERROR_CODE);
+
+	order = get_order(size);
+	if (order < 10)
+		free_pages((unsigned long)cpu, order);
+}
+
+static dma_addr_t dma_4u_map_page(struct device *dev, struct page *page,
+				  unsigned long offset, size_t sz,
+				  enum dma_data_direction direction,
+				  unsigned long attrs)
+{
+	struct iommu *iommu;
+	struct strbuf *strbuf;
+	iopte_t *base;
+	unsigned long flags, npages, oaddr;
+	unsigned long i, base_paddr, ctx;
+	u32 bus_addr, ret;
+	unsigned long iopte_protection;
+
+	iommu = dev->archdata.iommu;
+	strbuf = dev->archdata.stc;
+
+	if (unlikely(direction == DMA_NONE))
+		goto bad_no_ctx;
+
+	oaddr = (unsigned long)(page_address(page) + offset);
+	npages = IO_PAGE_ALIGN(oaddr + sz) - (oaddr & IO_PAGE_MASK);
+	npages >>= IO_PAGE_SHIFT;
+
+	base = alloc_npages(dev, iommu, npages);
+	spin_lock_irqsave(&iommu->lock, flags);
+	ctx = 0;
+	if (iommu->iommu_ctxflush)
+		ctx = iommu_alloc_ctx(iommu);
+	spin_unlock_irqrestore(&iommu->lock, flags);
+
+	if (unlikely(!base))
+		goto bad;
+
+	bus_addr = (iommu->tbl.table_map_base +
+		    ((base - iommu->page_table) << IO_PAGE_SHIFT));
+	ret = bus_addr | (oaddr & ~IO_PAGE_MASK);
+	base_paddr = __pa(oaddr & IO_PAGE_MASK);
+	if (strbuf->strbuf_enabled)
+		iopte_protection = IOPTE_STREAMING(ctx);
+	else
+		iopte_protection = IOPTE_CONSISTENT(ctx);
+	if (direction != DMA_TO_DEVICE)
+		iopte_protection |= IOPTE_WRITE;
+
+	for (i = 0; i < npages; i++, base++, base_paddr += IO_PAGE_SIZE)
+		iopte_val(*base) = iopte_protection | base_paddr;
+
+	return ret;
+
+bad:
+	iommu_free_ctx(iommu, ctx);
+bad_no_ctx:
+	if (printk_ratelimit())
+		WARN_ON(1);
+	return DMA_MAPPING_ERROR;
+}
+
+static void strbuf_flush(struct strbuf *strbuf, struct iommu *iommu,
+			 u32 vaddr, unsigned long ctx, unsigned long npages,
+			 enum dma_data_direction direction)
+{
+	int limit;
+
+	if (strbuf->strbuf_ctxflush &&
+	    iommu->iommu_ctxflush) {
+		unsigned long matchreg, flushreg;
+		u64 val;
+
+		flushreg = strbuf->strbuf_ctxflush;
+		matchreg = STC_CTXMATCH_ADDR(strbuf, ctx);
+
+		iommu_write(flushreg, ctx);
+		val = iommu_read(matchreg);
+		val &= 0xffff;
+		if (!val)
+			goto do_flush_sync;
+
+		while (val) {
+			if (val & 0x1)
+				iommu_write(flushreg, ctx);
+			val >>= 1;
+		}
+		val = iommu_read(matchreg);
+		if (unlikely(val)) {
+			printk(KERN_WARNING "strbuf_flush: ctx flush "
+			       "timeout matchreg[%llx] ctx[%lx]\n",
+			       val, ctx);
+			goto do_page_flush;
+		}
+	} else {
+		unsigned long i;
+
+	do_page_flush:
+		for (i = 0; i < npages; i++, vaddr += IO_PAGE_SIZE)
+			iommu_write(strbuf->strbuf_pflush, vaddr);
+	}
+
+do_flush_sync:
+	/* If the device could not have possibly put dirty data into
+	 * the streaming cache, no flush-flag synchronization needs
+	 * to be performed.
+	 */
+	if (direction == DMA_TO_DEVICE)
+		return;
+
+	STC_FLUSHFLAG_INIT(strbuf);
+	iommu_write(strbuf->strbuf_fsync, strbuf->strbuf_flushflag_pa);
+	(void) iommu_read(iommu->write_complete_reg);
+
+	limit = 100000;
+	while (!STC_FLUSHFLAG_SET(strbuf)) {
+		limit--;
+		if (!limit)
+			break;
+		udelay(1);
+		rmb();
+	}
+	if (!limit)
+		printk(KERN_WARNING "strbuf_flush: flushflag timeout "
+		       "vaddr[%08x] ctx[%lx] npages[%ld]\n",
+		       vaddr, ctx, npages);
+}
+
+static void dma_4u_unmap_page(struct device *dev, dma_addr_t bus_addr,
+			      size_t sz, enum dma_data_direction direction,
+			      unsigned long attrs)
+{
+	struct iommu *iommu;
+	struct strbuf *strbuf;
+	iopte_t *base;
+	unsigned long flags, npages, ctx, i;
+
+	if (unlikely(direction == DMA_NONE)) {
+		if (printk_ratelimit())
+			WARN_ON(1);
+		return;
+	}
+
+	iommu = dev->archdata.iommu;
+	strbuf = dev->archdata.stc;
+
+	npages = IO_PAGE_ALIGN(bus_addr + sz) - (bus_addr & IO_PAGE_MASK);
+	npages >>= IO_PAGE_SHIFT;
+	base = iommu->page_table +
+		((bus_addr - iommu->tbl.table_map_base) >> IO_PAGE_SHIFT);
+	bus_addr &= IO_PAGE_MASK;
+
+	spin_lock_irqsave(&iommu->lock, flags);
+
+	/* Record the context, if any. */
+	ctx = 0;
+	if (iommu->iommu_ctxflush)
+		ctx = (iopte_val(*base) & IOPTE_CONTEXT) >> 47UL;
+
+	/* Step 1: Kick data out of streaming buffers if necessary. */
+	if (strbuf->strbuf_enabled && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		strbuf_flush(strbuf, iommu, bus_addr, ctx,
+			     npages, direction);
+
+	/* Step 2: Clear out TSB entries. */
+	for (i = 0; i < npages; i++)
+		iopte_make_dummy(iommu, base + i);
+
+	iommu_free_ctx(iommu, ctx);
+	spin_unlock_irqrestore(&iommu->lock, flags);
+
+	iommu_tbl_range_free(&iommu->tbl, bus_addr, npages, IOMMU_ERROR_CODE);
+}
+
+static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
+			 int nelems, enum dma_data_direction direction,
+			 unsigned long attrs)
+{
+	struct scatterlist *s, *outs, *segstart;
+	unsigned long flags, handle, prot, ctx;
+	dma_addr_t dma_next = 0, dma_addr;
+	unsigned int max_seg_size;
+	unsigned long seg_boundary_size;
+	int outcount, incount, i;
+	struct strbuf *strbuf;
+	struct iommu *iommu;
+	unsigned long base_shift;
+
+	BUG_ON(direction == DMA_NONE);
+
+	iommu = dev->archdata.iommu;
+	strbuf = dev->archdata.stc;
+	if (nelems == 0 || !iommu)
+		return 0;
+
+	spin_lock_irqsave(&iommu->lock, flags);
+
+	ctx = 0;
+	if (iommu->iommu_ctxflush)
+		ctx = iommu_alloc_ctx(iommu);
+
+	if (strbuf->strbuf_enabled)
+		prot = IOPTE_STREAMING(ctx);
+	else
+		prot = IOPTE_CONSISTENT(ctx);
+	if (direction != DMA_TO_DEVICE)
+		prot |= IOPTE_WRITE;
+
+	outs = s = segstart = &sglist[0];
+	outcount = 1;
+	incount = nelems;
+	handle = 0;
+
+	/* Init first segment length for backout at failure */
+	outs->dma_length = 0;
+
+	max_seg_size = dma_get_max_seg_size(dev);
+	seg_boundary_size = dma_get_seg_boundary_nr_pages(dev, IO_PAGE_SHIFT);
+	base_shift = iommu->tbl.table_map_base >> IO_PAGE_SHIFT;
+	for_each_sg(sglist, s, nelems, i) {
+		unsigned long paddr, npages, entry, out_entry = 0, slen;
+		iopte_t *base;
+
+		slen = s->length;
+		/* Sanity check */
+		if (slen == 0) {
+			dma_next = 0;
+			continue;
+		}
+		/* Allocate iommu entries for that segment */
+		paddr = (unsigned long) SG_ENT_PHYS_ADDRESS(s);
+		npages = iommu_num_pages(paddr, slen, IO_PAGE_SIZE);
+		entry = iommu_tbl_range_alloc(dev, &iommu->tbl, npages,
+					      &handle, (unsigned long)(-1), 0);
+
+		/* Handle failure */
+		if (unlikely(entry == IOMMU_ERROR_CODE)) {
+			if (printk_ratelimit())
+				printk(KERN_INFO "iommu_alloc failed, iommu %p paddr %lx"
+				       " npages %lx\n", iommu, paddr, npages);
+			goto iommu_map_failed;
+		}
+
+		base = iommu->page_table + entry;
+
+		/* Convert entry to a dma_addr_t */
+		dma_addr = iommu->tbl.table_map_base +
+			(entry << IO_PAGE_SHIFT);
+		dma_addr |= (s->offset & ~IO_PAGE_MASK);
+
+		/* Insert into HW table */
+		paddr &= IO_PAGE_MASK;
+		while (npages--) {
+			iopte_val(*base) = prot | paddr;
+			base++;
+			paddr += IO_PAGE_SIZE;
+		}
+
+		/* If we are in an open segment, try merging */
+		if (segstart != s) {
+			/* We cannot merge if:
+			 * - allocated dma_addr isn't contiguous to previous allocation
+			 */
+			if ((dma_addr != dma_next) ||
+			    (outs->dma_length + s->length > max_seg_size) ||
+			    (is_span_boundary(out_entry, base_shift,
+					      seg_boundary_size, outs, s))) {
+				/* Can't merge: create a new segment */
+				segstart = s;
+				outcount++;
+				outs = sg_next(outs);
+			} else {
+				outs->dma_length += s->length;
+			}
+		}
+
+		if (segstart == s) {
+			/* This is a new segment, fill entries */
+			outs->dma_address = dma_addr;
+			outs->dma_length = slen;
+			out_entry = entry;
+		}
+
+		/* Calculate next page pointer for contiguous check */
+		dma_next = dma_addr + slen;
+	}
+
+	spin_unlock_irqrestore(&iommu->lock, flags);
+
+	if (outcount < incount) {
+		outs = sg_next(outs);
+		outs->dma_address = DMA_MAPPING_ERROR;
+		outs->dma_length = 0;
+	}
+
+	return outcount;
+
+iommu_map_failed:
+	for_each_sg(sglist, s, nelems, i) {
+		if (s->dma_length != 0) {
+			unsigned long vaddr, npages, entry, j;
+			iopte_t *base;
+
+			vaddr = s->dma_address & IO_PAGE_MASK;
+			npages = iommu_num_pages(s->dma_address, s->dma_length,
+						 IO_PAGE_SIZE);
+
+			entry = (vaddr - iommu->tbl.table_map_base)
+				>> IO_PAGE_SHIFT;
+			base = iommu->page_table + entry;
+
+			for (j = 0; j < npages; j++)
+				iopte_make_dummy(iommu, base + j);
+
+			iommu_tbl_range_free(&iommu->tbl, vaddr, npages,
+					     IOMMU_ERROR_CODE);
+
+			s->dma_address = DMA_MAPPING_ERROR;
+			s->dma_length = 0;
+		}
+		if (s == outs)
+			break;
+	}
+	spin_unlock_irqrestore(&iommu->lock, flags);
+
+	return 0;
+}
+
+/* If contexts are being used, they are the same in all of the mappings
+ * we make for a particular SG.
+ */
+static unsigned long fetch_sg_ctx(struct iommu *iommu, struct scatterlist *sg)
+{
+	unsigned long ctx = 0;
+
+	if (iommu->iommu_ctxflush) {
+		iopte_t *base;
+		u32 bus_addr;
+		struct iommu_map_table *tbl = &iommu->tbl;
+
+		bus_addr = sg->dma_address & IO_PAGE_MASK;
+		base = iommu->page_table +
+			((bus_addr - tbl->table_map_base) >> IO_PAGE_SHIFT);
+
+		ctx = (iopte_val(*base) & IOPTE_CONTEXT) >> 47UL;
+	}
+	return ctx;
+}
+
+static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
+			    int nelems, enum dma_data_direction direction,
+			    unsigned long attrs)
+{
+	unsigned long flags, ctx;
+	struct scatterlist *sg;
+	struct strbuf *strbuf;
+	struct iommu *iommu;
+
+	BUG_ON(direction == DMA_NONE);
+
+	iommu = dev->archdata.iommu;
+	strbuf = dev->archdata.stc;
+
+	ctx = fetch_sg_ctx(iommu, sglist);
+
+	spin_lock_irqsave(&iommu->lock, flags);
+
+	sg = sglist;
+	while (nelems--) {
+		dma_addr_t dma_handle = sg->dma_address;
+		unsigned int len = sg->dma_length;
+		unsigned long npages, entry;
+		iopte_t *base;
+		int i;
+
+		if (!len)
+			break;
+		npages = iommu_num_pages(dma_handle, len, IO_PAGE_SIZE);
+
+		entry = ((dma_handle - iommu->tbl.table_map_base)
+			 >> IO_PAGE_SHIFT);
+		base = iommu->page_table + entry;
+
+		dma_handle &= IO_PAGE_MASK;
+		if (strbuf->strbuf_enabled && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+			strbuf_flush(strbuf, iommu, dma_handle, ctx,
+				     npages, direction);
+
+		for (i = 0; i < npages; i++)
+			iopte_make_dummy(iommu, base + i);
+
+		iommu_tbl_range_free(&iommu->tbl, dma_handle, npages,
+				     IOMMU_ERROR_CODE);
+		sg = sg_next(sg);
+	}
+
+	iommu_free_ctx(iommu, ctx);
+
+	spin_unlock_irqrestore(&iommu->lock, flags);
+}
+
+static void dma_4u_sync_single_for_cpu(struct device *dev,
+				       dma_addr_t bus_addr, size_t sz,
+				       enum dma_data_direction direction)
+{
+	struct iommu *iommu;
+	struct strbuf *strbuf;
+	unsigned long flags, ctx, npages;
+
+	iommu = dev->archdata.iommu;
+	strbuf = dev->archdata.stc;
+
+	if (!strbuf->strbuf_enabled)
+		return;
+
+	spin_lock_irqsave(&iommu->lock, flags);
+
+	npages = IO_PAGE_ALIGN(bus_addr + sz) - (bus_addr & IO_PAGE_MASK);
+	npages >>= IO_PAGE_SHIFT;
+	bus_addr &= IO_PAGE_MASK;
+
+	/* Step 1: Record the context, if any. */
+	ctx = 0;
+	if (iommu->iommu_ctxflush &&
+	    strbuf->strbuf_ctxflush) {
+		iopte_t *iopte;
+		struct iommu_map_table *tbl = &iommu->tbl;
+
+		iopte = iommu->page_table +
+			((bus_addr - tbl->table_map_base)>>IO_PAGE_SHIFT);
+		ctx = (iopte_val(*iopte) & IOPTE_CONTEXT) >> 47UL;
+	}
+
+	/* Step 2: Kick data out of streaming buffers. */
+	strbuf_flush(strbuf, iommu, bus_addr, ctx, npages, direction);
+
+	spin_unlock_irqrestore(&iommu->lock, flags);
+}
+
+static void dma_4u_sync_sg_for_cpu(struct device *dev,
+				   struct scatterlist *sglist, int nelems,
+				   enum dma_data_direction direction)
+{
+	struct iommu *iommu;
+	struct strbuf *strbuf;
+	unsigned long flags, ctx, npages, i;
+	struct scatterlist *sg, *sgprv;
+	u32 bus_addr;
+
+	iommu = dev->archdata.iommu;
+	strbuf = dev->archdata.stc;
+
+	if (!strbuf->strbuf_enabled)
+		return;
+
+	spin_lock_irqsave(&iommu->lock, flags);
+
+	/* Step 1: Record the context, if any. */
+	ctx = 0;
+	if (iommu->iommu_ctxflush &&
+	    strbuf->strbuf_ctxflush) {
+		iopte_t *iopte;
+		struct iommu_map_table *tbl = &iommu->tbl;
+
+		iopte = iommu->page_table + ((sglist[0].dma_address -
+			tbl->table_map_base) >> IO_PAGE_SHIFT);
+		ctx = (iopte_val(*iopte) & IOPTE_CONTEXT) >> 47UL;
+	}
+
+	/* Step 2: Kick data out of streaming buffers. */
+	bus_addr = sglist[0].dma_address & IO_PAGE_MASK;
+	sgprv = NULL;
+	for_each_sg(sglist, sg, nelems, i) {
+		if (sg->dma_length == 0)
+			break;
+		sgprv = sg;
+	}
+
+	npages = (IO_PAGE_ALIGN(sgprv->dma_address + sgprv->dma_length)
+		  - bus_addr) >> IO_PAGE_SHIFT;
+	strbuf_flush(strbuf, iommu, bus_addr, ctx, npages, direction);
+
+	spin_unlock_irqrestore(&iommu->lock, flags);
+}
+
+static int dma_4u_supported(struct device *dev, u64 device_mask)
+{
+	struct iommu *iommu = dev->archdata.iommu;
+
+	if (ali_sound_dma_hack(dev, device_mask))
+		return 1;
+
+	if (device_mask < iommu->dma_addr_mask)
+		return 0;
+	return 1;
+}
+
+static const struct dma_map_ops sun4u_dma_ops = {
+	.alloc			= dma_4u_alloc_coherent,
+	.free			= dma_4u_free_coherent,
+	.map_page		= dma_4u_map_page,
+	.unmap_page		= dma_4u_unmap_page,
+	.map_sg			= dma_4u_map_sg,
+	.unmap_sg		= dma_4u_unmap_sg,
+	.sync_single_for_cpu	= dma_4u_sync_single_for_cpu,
+	.sync_sg_for_cpu	= dma_4u_sync_sg_for_cpu,
+	.dma_supported		= dma_4u_supported,
+};
+
+const struct dma_map_ops *dma_ops = &sun4u_dma_ops;
+EXPORT_SYMBOL(dma_ops);