dma-mapping: move all DMA mapping code to kernel/dma

Currently the code is split over various files with dma- prefixes in the
lib/ and drives/base directories, and the number of files keeps growing.
Move them into a single directory to keep the code together and remove
the file name prefixes.  To match the irq infrastructure this directory
is placed under the kernel/ directory.

Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 0 insertions, 1087 deletions

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
deleted file mode 100644
index 04b68d9dffac..000000000000
--- a/lib/swiotlb.c
+++ /dev/null
@@ -1,1087 +0,0 @@
-/*
- * Dynamic DMA mapping support.
- *
- * This implementation is a fallback for platforms that do not support
- * I/O TLBs (aka DMA address translation hardware).
- * Copyright (C) 2000 Asit Mallick <Asit.K.Mallick@intel.com>
- * Copyright (C) 2000 Goutham Rao <goutham.rao@intel.com>
- * Copyright (C) 2000, 2003 Hewlett-Packard Co
- *	David Mosberger-Tang <davidm@hpl.hp.com>
- *
- * 03/05/07 davidm	Switch from PCI-DMA to generic device DMA API.
- * 00/12/13 davidm	Rename to swiotlb.c and add mark_clean() to avoid
- *			unnecessary i-cache flushing.
- * 04/07/.. ak		Better overflow handling. Assorted fixes.
- * 05/09/10 linville	Add support for syncing ranges, support syncing for
- *			DMA_BIDIRECTIONAL mappings, miscellaneous cleanup.
- * 08/12/11 beckyb	Add highmem support
- */
-
-#include <linux/cache.h>
-#include <linux/dma-direct.h>
-#include <linux/mm.h>
-#include <linux/export.h>
-#include <linux/spinlock.h>
-#include <linux/string.h>
-#include <linux/swiotlb.h>
-#include <linux/pfn.h>
-#include <linux/types.h>
-#include <linux/ctype.h>
-#include <linux/highmem.h>
-#include <linux/gfp.h>
-#include <linux/scatterlist.h>
-#include <linux/mem_encrypt.h>
-#include <linux/set_memory.h>
-
-#include <asm/io.h>
-#include <asm/dma.h>
-
-#include <linux/init.h>
-#include <linux/bootmem.h>
-#include <linux/iommu-helper.h>
-
-#define CREATE_TRACE_POINTS
-#include <trace/events/swiotlb.h>
-
-#define OFFSET(val,align) ((unsigned long)	\
-	                   ( (val) & ( (align) - 1)))
-
-#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
-
-/*
- * Minimum IO TLB size to bother booting with.  Systems with mainly
- * 64bit capable cards will only lightly use the swiotlb.  If we can't
- * allocate a contiguous 1MB, we're probably in trouble anyway.
- */
-#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
-
-enum swiotlb_force swiotlb_force;
-
-/*
- * Used to do a quick range check in swiotlb_tbl_unmap_single and
- * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
- * API.
- */
-static phys_addr_t io_tlb_start, io_tlb_end;
-
-/*
- * The number of IO TLB blocks (in groups of 64) between io_tlb_start and
- * io_tlb_end.  This is command line adjustable via setup_io_tlb_npages.
- */
-static unsigned long io_tlb_nslabs;
-
-/*
- * When the IOMMU overflows we return a fallback buffer. This sets the size.
- */
-static unsigned long io_tlb_overflow = 32*1024;
-
-static phys_addr_t io_tlb_overflow_buffer;
-
-/*
- * This is a free list describing the number of free entries available from
- * each index
- */
-static unsigned int *io_tlb_list;
-static unsigned int io_tlb_index;
-
-/*
- * Max segment that we can provide which (if pages are contingous) will
- * not be bounced (unless SWIOTLB_FORCE is set).
- */
-unsigned int max_segment;
-
-/*
- * We need to save away the original address corresponding to a mapped entry
- * for the sync operations.
- */
-#define INVALID_PHYS_ADDR (~(phys_addr_t)0)
-static phys_addr_t *io_tlb_orig_addr;
-
-/*
- * Protect the above data structures in the map and unmap calls
- */
-static DEFINE_SPINLOCK(io_tlb_lock);
-
-static int late_alloc;
-
-static int __init
-setup_io_tlb_npages(char *str)
-{
-	if (isdigit(*str)) {
-		io_tlb_nslabs = simple_strtoul(str, &str, 0);
-		/* avoid tail segment of size < IO_TLB_SEGSIZE */
-		io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
-	}
-	if (*str == ',')
-		++str;
-	if (!strcmp(str, "force")) {
-		swiotlb_force = SWIOTLB_FORCE;
-	} else if (!strcmp(str, "noforce")) {
-		swiotlb_force = SWIOTLB_NO_FORCE;
-		io_tlb_nslabs = 1;
-	}
-
-	return 0;
-}
-early_param("swiotlb", setup_io_tlb_npages);
-/* make io_tlb_overflow tunable too? */
-
-unsigned long swiotlb_nr_tbl(void)
-{
-	return io_tlb_nslabs;
-}
-EXPORT_SYMBOL_GPL(swiotlb_nr_tbl);
-
-unsigned int swiotlb_max_segment(void)
-{
-	return max_segment;
-}
-EXPORT_SYMBOL_GPL(swiotlb_max_segment);
-
-void swiotlb_set_max_segment(unsigned int val)
-{
-	if (swiotlb_force == SWIOTLB_FORCE)
-		max_segment = 1;
-	else
-		max_segment = rounddown(val, PAGE_SIZE);
-}
-
-/* default to 64MB */
-#define IO_TLB_DEFAULT_SIZE (64UL<<20)
-unsigned long swiotlb_size_or_default(void)
-{
-	unsigned long size;
-
-	size = io_tlb_nslabs << IO_TLB_SHIFT;
-
-	return size ? size : (IO_TLB_DEFAULT_SIZE);
-}
-
-static bool no_iotlb_memory;
-
-void swiotlb_print_info(void)
-{
-	unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;
-	unsigned char *vstart, *vend;
-
-	if (no_iotlb_memory) {
-		pr_warn("software IO TLB: No low mem\n");
-		return;
-	}
-
-	vstart = phys_to_virt(io_tlb_start);
-	vend = phys_to_virt(io_tlb_end);
-
-	printk(KERN_INFO "software IO TLB [mem %#010llx-%#010llx] (%luMB) mapped at [%p-%p]\n",
-	       (unsigned long long)io_tlb_start,
-	       (unsigned long long)io_tlb_end,
-	       bytes >> 20, vstart, vend - 1);
-}
-
-/*
- * Early SWIOTLB allocation may be too early to allow an architecture to
- * perform the desired operations.  This function allows the architecture to
- * call SWIOTLB when the operations are possible.  It needs to be called
- * before the SWIOTLB memory is used.
- */
-void __init swiotlb_update_mem_attributes(void)
-{
-	void *vaddr;
-	unsigned long bytes;
-
-	if (no_iotlb_memory || late_alloc)
-		return;
-
-	vaddr = phys_to_virt(io_tlb_start);
-	bytes = PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT);
-	set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
-	memset(vaddr, 0, bytes);
-
-	vaddr = phys_to_virt(io_tlb_overflow_buffer);
-	bytes = PAGE_ALIGN(io_tlb_overflow);
-	set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
-	memset(vaddr, 0, bytes);
-}
-
-int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
-{
-	void *v_overflow_buffer;
-	unsigned long i, bytes;
-
-	bytes = nslabs << IO_TLB_SHIFT;
-
-	io_tlb_nslabs = nslabs;
-	io_tlb_start = __pa(tlb);
-	io_tlb_end = io_tlb_start + bytes;
-
-	/*
-	 * Get the overflow emergency buffer
-	 */
-	v_overflow_buffer = memblock_virt_alloc_low_nopanic(
-						PAGE_ALIGN(io_tlb_overflow),
-						PAGE_SIZE);
-	if (!v_overflow_buffer)
-		return -ENOMEM;
-
-	io_tlb_overflow_buffer = __pa(v_overflow_buffer);
-
-	/*
-	 * Allocate and initialize the free list array.  This array is used
-	 * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
-	 * between io_tlb_start and io_tlb_end.
-	 */
-	io_tlb_list = memblock_virt_alloc(
-				PAGE_ALIGN(io_tlb_nslabs * sizeof(int)),
-				PAGE_SIZE);
-	io_tlb_orig_addr = memblock_virt_alloc(
-				PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)),
-				PAGE_SIZE);
-	for (i = 0; i < io_tlb_nslabs; i++) {
-		io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
-		io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
-	}
-	io_tlb_index = 0;
-
-	if (verbose)
-		swiotlb_print_info();
-
-	swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT);
-	return 0;
-}
-
-/*
- * Statically reserve bounce buffer space and initialize bounce buffer data
- * structures for the software IO TLB used to implement the DMA API.
- */
-void  __init
-swiotlb_init(int verbose)
-{
-	size_t default_size = IO_TLB_DEFAULT_SIZE;
-	unsigned char *vstart;
-	unsigned long bytes;
-
-	if (!io_tlb_nslabs) {
-		io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
-		io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
-	}
-
-	bytes = io_tlb_nslabs << IO_TLB_SHIFT;
-
-	/* Get IO TLB memory from the low pages */
-	vstart = memblock_virt_alloc_low_nopanic(PAGE_ALIGN(bytes), PAGE_SIZE);
-	if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose))
-		return;
-
-	if (io_tlb_start)
-		memblock_free_early(io_tlb_start,
-				    PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
-	pr_warn("Cannot allocate SWIOTLB buffer");
-	no_iotlb_memory = true;
-}
-
-/*
- * Systems with larger DMA zones (those that don't support ISA) can
- * initialize the swiotlb later using the slab allocator if needed.
- * This should be just like above, but with some error catching.
- */
-int
-swiotlb_late_init_with_default_size(size_t default_size)
-{
-	unsigned long bytes, req_nslabs = io_tlb_nslabs;
-	unsigned char *vstart = NULL;
-	unsigned int order;
-	int rc = 0;
-
-	if (!io_tlb_nslabs) {
-		io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
-		io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
-	}
-
-	/*
-	 * Get IO TLB memory from the low pages
-	 */
-	order = get_order(io_tlb_nslabs << IO_TLB_SHIFT);
-	io_tlb_nslabs = SLABS_PER_PAGE << order;
-	bytes = io_tlb_nslabs << IO_TLB_SHIFT;
-
-	while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
-		vstart = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
-						  order);
-		if (vstart)
-			break;
-		order--;
-	}
-
-	if (!vstart) {
-		io_tlb_nslabs = req_nslabs;
-		return -ENOMEM;
-	}
-	if (order != get_order(bytes)) {
-		printk(KERN_WARNING "Warning: only able to allocate %ld MB "
-		       "for software IO TLB\n", (PAGE_SIZE << order) >> 20);
-		io_tlb_nslabs = SLABS_PER_PAGE << order;
-	}
-	rc = swiotlb_late_init_with_tbl(vstart, io_tlb_nslabs);
-	if (rc)
-		free_pages((unsigned long)vstart, order);
-
-	return rc;
-}
-
-int
-swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
-{
-	unsigned long i, bytes;
-	unsigned char *v_overflow_buffer;
-
-	bytes = nslabs << IO_TLB_SHIFT;
-
-	io_tlb_nslabs = nslabs;
-	io_tlb_start = virt_to_phys(tlb);
-	io_tlb_end = io_tlb_start + bytes;
-
-	set_memory_decrypted((unsigned long)tlb, bytes >> PAGE_SHIFT);
-	memset(tlb, 0, bytes);
-
-	/*
-	 * Get the overflow emergency buffer
-	 */
-	v_overflow_buffer = (void *)__get_free_pages(GFP_DMA,
-						     get_order(io_tlb_overflow));
-	if (!v_overflow_buffer)
-		goto cleanup2;
-
-	set_memory_decrypted((unsigned long)v_overflow_buffer,
-			io_tlb_overflow >> PAGE_SHIFT);
-	memset(v_overflow_buffer, 0, io_tlb_overflow);
-	io_tlb_overflow_buffer = virt_to_phys(v_overflow_buffer);
-
-	/*
-	 * Allocate and initialize the free list array.  This array is used
-	 * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
-	 * between io_tlb_start and io_tlb_end.
-	 */
-	io_tlb_list = (unsigned int *)__get_free_pages(GFP_KERNEL,
-	                              get_order(io_tlb_nslabs * sizeof(int)));
-	if (!io_tlb_list)
-		goto cleanup3;
-
-	io_tlb_orig_addr = (phys_addr_t *)
-		__get_free_pages(GFP_KERNEL,
-				 get_order(io_tlb_nslabs *
-					   sizeof(phys_addr_t)));
-	if (!io_tlb_orig_addr)
-		goto cleanup4;
-
-	for (i = 0; i < io_tlb_nslabs; i++) {
-		io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
-		io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
-	}
-	io_tlb_index = 0;
-
-	swiotlb_print_info();
-
-	late_alloc = 1;
-
-	swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT);
-
-	return 0;
-
-cleanup4:
-	free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
-	                                                 sizeof(int)));
-	io_tlb_list = NULL;
-cleanup3:
-	free_pages((unsigned long)v_overflow_buffer,
-		   get_order(io_tlb_overflow));
-	io_tlb_overflow_buffer = 0;
-cleanup2:
-	io_tlb_end = 0;
-	io_tlb_start = 0;
-	io_tlb_nslabs = 0;
-	max_segment = 0;
-	return -ENOMEM;
-}
-
-void __init swiotlb_exit(void)
-{
-	if (!io_tlb_orig_addr)
-		return;
-
-	if (late_alloc) {
-		free_pages((unsigned long)phys_to_virt(io_tlb_overflow_buffer),
-			   get_order(io_tlb_overflow));
-		free_pages((unsigned long)io_tlb_orig_addr,
-			   get_order(io_tlb_nslabs * sizeof(phys_addr_t)));
-		free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
-								 sizeof(int)));
-		free_pages((unsigned long)phys_to_virt(io_tlb_start),
-			   get_order(io_tlb_nslabs << IO_TLB_SHIFT));
-	} else {
-		memblock_free_late(io_tlb_overflow_buffer,
-				   PAGE_ALIGN(io_tlb_overflow));
-		memblock_free_late(__pa(io_tlb_orig_addr),
-				   PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
-		memblock_free_late(__pa(io_tlb_list),
-				   PAGE_ALIGN(io_tlb_nslabs * sizeof(int)));
-		memblock_free_late(io_tlb_start,
-				   PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
-	}
-	io_tlb_nslabs = 0;
-	max_segment = 0;
-}
-
-int is_swiotlb_buffer(phys_addr_t paddr)
-{
-	return paddr >= io_tlb_start && paddr < io_tlb_end;
-}
-
-/*
- * Bounce: copy the swiotlb buffer back to the original dma location
- */
-static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
-			   size_t size, enum dma_data_direction dir)
-{
-	unsigned long pfn = PFN_DOWN(orig_addr);
-	unsigned char *vaddr = phys_to_virt(tlb_addr);
-
-	if (PageHighMem(pfn_to_page(pfn))) {
-		/* The buffer does not have a mapping.  Map it in and copy */
-		unsigned int offset = orig_addr & ~PAGE_MASK;
-		char *buffer;
-		unsigned int sz = 0;
-		unsigned long flags;
-
-		while (size) {
-			sz = min_t(size_t, PAGE_SIZE - offset, size);
-
-			local_irq_save(flags);
-			buffer = kmap_atomic(pfn_to_page(pfn));
-			if (dir == DMA_TO_DEVICE)
-				memcpy(vaddr, buffer + offset, sz);
-			else
-				memcpy(buffer + offset, vaddr, sz);
-			kunmap_atomic(buffer);
-			local_irq_restore(flags);
-
-			size -= sz;
-			pfn++;
-			vaddr += sz;
-			offset = 0;
-		}
-	} else if (dir == DMA_TO_DEVICE) {
-		memcpy(vaddr, phys_to_virt(orig_addr), size);
-	} else {
-		memcpy(phys_to_virt(orig_addr), vaddr, size);
-	}
-}
-
-phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
-				   dma_addr_t tbl_dma_addr,
-				   phys_addr_t orig_addr, size_t size,
-				   enum dma_data_direction dir,
-				   unsigned long attrs)
-{
-	unsigned long flags;
-	phys_addr_t tlb_addr;
-	unsigned int nslots, stride, index, wrap;
-	int i;
-	unsigned long mask;
-	unsigned long offset_slots;
-	unsigned long max_slots;
-
-	if (no_iotlb_memory)
-		panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
-
-	if (mem_encrypt_active())
-		pr_warn_once("%s is active and system is using DMA bounce buffers\n",
-			     sme_active() ? "SME" : "SEV");
-
-	mask = dma_get_seg_boundary(hwdev);
-
-	tbl_dma_addr &= mask;
-
-	offset_slots = ALIGN(tbl_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
-
-	/*
- 	 * Carefully handle integer overflow which can occur when mask == ~0UL.
- 	 */
-	max_slots = mask + 1
-		    ? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT
-		    : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
-
-	/*
-	 * For mappings greater than or equal to a page, we limit the stride
-	 * (and hence alignment) to a page size.
-	 */
-	nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
-	if (size >= PAGE_SIZE)
-		stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
-	else
-		stride = 1;
-
-	BUG_ON(!nslots);
-
-	/*
-	 * Find suitable number of IO TLB entries size that will fit this
-	 * request and allocate a buffer from that IO TLB pool.
-	 */
-	spin_lock_irqsave(&io_tlb_lock, flags);
-	index = ALIGN(io_tlb_index, stride);
-	if (index >= io_tlb_nslabs)
-		index = 0;
-	wrap = index;
-
-	do {
-		while (iommu_is_span_boundary(index, nslots, offset_slots,
-					      max_slots)) {
-			index += stride;
-			if (index >= io_tlb_nslabs)
-				index = 0;
-			if (index == wrap)
-				goto not_found;
-		}
-
-		/*
-		 * If we find a slot that indicates we have 'nslots' number of
-		 * contiguous buffers, we allocate the buffers from that slot
-		 * and mark the entries as '0' indicating unavailable.
-		 */
-		if (io_tlb_list[index] >= nslots) {
-			int count = 0;
-
-			for (i = index; i < (int) (index + nslots); i++)
-				io_tlb_list[i] = 0;
-			for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) && io_tlb_list[i]; i--)
-				io_tlb_list[i] = ++count;
-			tlb_addr = io_tlb_start + (index << IO_TLB_SHIFT);
-
-			/*
-			 * Update the indices to avoid searching in the next
-			 * round.
-			 */
-			io_tlb_index = ((index + nslots) < io_tlb_nslabs
-					? (index + nslots) : 0);
-
-			goto found;
-		}
-		index += stride;
-		if (index >= io_tlb_nslabs)
-			index = 0;
-	} while (index != wrap);
-
-not_found:
-	spin_unlock_irqrestore(&io_tlb_lock, flags);
-	if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
-		dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n", size);
-	return SWIOTLB_MAP_ERROR;
-found:
-	spin_unlock_irqrestore(&io_tlb_lock, flags);
-
-	/*
-	 * Save away the mapping from the original address to the DMA address.
-	 * This is needed when we sync the memory.  Then we sync the buffer if
-	 * needed.
-	 */
-	for (i = 0; i < nslots; i++)
-		io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
-	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
-	    (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
-		swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE);
-
-	return tlb_addr;
-}
-
-/*
- * Allocates bounce buffer and returns its physical address.
- */
-static phys_addr_t
-map_single(struct device *hwdev, phys_addr_t phys, size_t size,
-	   enum dma_data_direction dir, unsigned long attrs)
-{
-	dma_addr_t start_dma_addr;
-
-	if (swiotlb_force == SWIOTLB_NO_FORCE) {
-		dev_warn_ratelimited(hwdev, "Cannot do DMA to address %pa\n",
-				     &phys);
-		return SWIOTLB_MAP_ERROR;
-	}
-
-	start_dma_addr = __phys_to_dma(hwdev, io_tlb_start);
-	return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size,
-				      dir, attrs);
-}
-
-/*
- * tlb_addr is the physical address of the bounce buffer to unmap.
- */
-void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
-			      size_t size, enum dma_data_direction dir,
-			      unsigned long attrs)
-{
-	unsigned long flags;
-	int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
-	int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
-	phys_addr_t orig_addr = io_tlb_orig_addr[index];
-
-	/*
-	 * First, sync the memory before unmapping the entry
-	 */
-	if (orig_addr != INVALID_PHYS_ADDR &&
-	    !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
-	    ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
-		swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
-
-	/*
-	 * Return the buffer to the free list by setting the corresponding
-	 * entries to indicate the number of contiguous entries available.
-	 * While returning the entries to the free list, we merge the entries
-	 * with slots below and above the pool being returned.
-	 */
-	spin_lock_irqsave(&io_tlb_lock, flags);
-	{
-		count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
-			 io_tlb_list[index + nslots] : 0);
-		/*
-		 * Step 1: return the slots to the free list, merging the
-		 * slots with superceeding slots
-		 */
-		for (i = index + nslots - 1; i >= index; i--) {
-			io_tlb_list[i] = ++count;
-			io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
-		}
-		/*
-		 * Step 2: merge the returned slots with the preceding slots,
-		 * if available (non zero)
-		 */
-		for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--)
-			io_tlb_list[i] = ++count;
-	}
-	spin_unlock_irqrestore(&io_tlb_lock, flags);
-}
-
-void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
-			     size_t size, enum dma_data_direction dir,
-			     enum dma_sync_target target)
-{
-	int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
-	phys_addr_t orig_addr = io_tlb_orig_addr[index];
-
-	if (orig_addr == INVALID_PHYS_ADDR)
-		return;
-	orig_addr += (unsigned long)tlb_addr & ((1 << IO_TLB_SHIFT) - 1);
-
-	switch (target) {
-	case SYNC_FOR_CPU:
-		if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
-			swiotlb_bounce(orig_addr, tlb_addr,
-				       size, DMA_FROM_DEVICE);
-		else
-			BUG_ON(dir != DMA_TO_DEVICE);
-		break;
-	case SYNC_FOR_DEVICE:
-		if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
-			swiotlb_bounce(orig_addr, tlb_addr,
-				       size, DMA_TO_DEVICE);
-		else
-			BUG_ON(dir != DMA_FROM_DEVICE);
-		break;
-	default:
-		BUG();
-	}
-}
-
-static inline bool dma_coherent_ok(struct device *dev, dma_addr_t addr,
-		size_t size)
-{
-	u64 mask = DMA_BIT_MASK(32);
-
-	if (dev && dev->coherent_dma_mask)
-		mask = dev->coherent_dma_mask;
-	return addr + size - 1 <= mask;
-}
-
-static void *
-swiotlb_alloc_buffer(struct device *dev, size_t size, dma_addr_t *dma_handle,
-		unsigned long attrs)
-{
-	phys_addr_t phys_addr;
-
-	if (swiotlb_force == SWIOTLB_NO_FORCE)
-		goto out_warn;
-
-	phys_addr = swiotlb_tbl_map_single(dev,
-			__phys_to_dma(dev, io_tlb_start),
-			0, size, DMA_FROM_DEVICE, attrs);
-	if (phys_addr == SWIOTLB_MAP_ERROR)
-		goto out_warn;
-
-	*dma_handle = __phys_to_dma(dev, phys_addr);
-	if (!dma_coherent_ok(dev, *dma_handle, size))
-		goto out_unmap;
-
-	memset(phys_to_virt(phys_addr), 0, size);
-	return phys_to_virt(phys_addr);
-
-out_unmap:
-	dev_warn(dev, "hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n",
-		(unsigned long long)dev->coherent_dma_mask,
-		(unsigned long long)*dma_handle);
-
-	/*
-	 * DMA_TO_DEVICE to avoid memcpy in unmap_single.
-	 * DMA_ATTR_SKIP_CPU_SYNC is optional.
-	 */
-	swiotlb_tbl_unmap_single(dev, phys_addr, size, DMA_TO_DEVICE,
-			DMA_ATTR_SKIP_CPU_SYNC);
-out_warn:
-	if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit()) {
-		dev_warn(dev,
-			"swiotlb: coherent allocation failed, size=%zu\n",
-			size);
-		dump_stack();
-	}
-	return NULL;
-}
-
-static bool swiotlb_free_buffer(struct device *dev, size_t size,
-		dma_addr_t dma_addr)
-{
-	phys_addr_t phys_addr = dma_to_phys(dev, dma_addr);
-
-	WARN_ON_ONCE(irqs_disabled());
-
-	if (!is_swiotlb_buffer(phys_addr))
-		return false;
-
-	/*
-	 * DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single.
-	 * DMA_ATTR_SKIP_CPU_SYNC is optional.
-	 */
-	swiotlb_tbl_unmap_single(dev, phys_addr, size, DMA_TO_DEVICE,
-				 DMA_ATTR_SKIP_CPU_SYNC);
-	return true;
-}
-
-static void
-swiotlb_full(struct device *dev, size_t size, enum dma_data_direction dir,
-	     int do_panic)
-{
-	if (swiotlb_force == SWIOTLB_NO_FORCE)
-		return;
-
-	/*
-	 * Ran out of IOMMU space for this operation. This is very bad.
-	 * Unfortunately the drivers cannot handle this operation properly.
-	 * unless they check for dma_mapping_error (most don't)
-	 * When the mapping is small enough return a static buffer to limit
-	 * the damage, or panic when the transfer is too big.
-	 */
-	dev_err_ratelimited(dev, "DMA: Out of SW-IOMMU space for %zu bytes\n",
-			    size);
-
-	if (size <= io_tlb_overflow || !do_panic)
-		return;
-
-	if (dir == DMA_BIDIRECTIONAL)
-		panic("DMA: Random memory could be DMA accessed\n");
-	if (dir == DMA_FROM_DEVICE)
-		panic("DMA: Random memory could be DMA written\n");
-	if (dir == DMA_TO_DEVICE)
-		panic("DMA: Random memory could be DMA read\n");
-}
-
-/*
- * Map a single buffer of the indicated size for DMA in streaming mode.  The
- * physical address to use is returned.
- *
- * Once the device is given the dma address, the device owns this memory until
- * either swiotlb_unmap_page or swiotlb_dma_sync_single is performed.
- */
-dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
-			    unsigned long offset, size_t size,
-			    enum dma_data_direction dir,
-			    unsigned long attrs)
-{
-	phys_addr_t map, phys = page_to_phys(page) + offset;
-	dma_addr_t dev_addr = phys_to_dma(dev, phys);
-
-	BUG_ON(dir == DMA_NONE);
-	/*
-	 * If the address happens to be in the device's DMA window,
-	 * we can safely return the device addr and not worry about bounce
-	 * buffering it.
-	 */
-	if (dma_capable(dev, dev_addr, size) && swiotlb_force != SWIOTLB_FORCE)
-		return dev_addr;
-
-	trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
-
-	/* Oh well, have to allocate and map a bounce buffer. */
-	map = map_single(dev, phys, size, dir, attrs);
-	if (map == SWIOTLB_MAP_ERROR) {
-		swiotlb_full(dev, size, dir, 1);
-		return __phys_to_dma(dev, io_tlb_overflow_buffer);
-	}
-
-	dev_addr = __phys_to_dma(dev, map);
-
-	/* Ensure that the address returned is DMA'ble */
-	if (dma_capable(dev, dev_addr, size))
-		return dev_addr;
-
-	attrs |= DMA_ATTR_SKIP_CPU_SYNC;
-	swiotlb_tbl_unmap_single(dev, map, size, dir, attrs);
-
-	return __phys_to_dma(dev, io_tlb_overflow_buffer);
-}
-
-/*
- * Unmap a single streaming mode DMA translation.  The dma_addr and size must
- * match what was provided for in a previous swiotlb_map_page call.  All
- * other usages are undefined.
- *
- * After this call, reads by the cpu to the buffer are guaranteed to see
- * whatever the device wrote there.
- */
-static void unmap_single(struct device *hwdev, dma_addr_t dev_addr,
-			 size_t size, enum dma_data_direction dir,
-			 unsigned long attrs)
-{
-	phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
-
-	BUG_ON(dir == DMA_NONE);
-
-	if (is_swiotlb_buffer(paddr)) {
-		swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs);
-		return;
-	}
-
-	if (dir != DMA_FROM_DEVICE)
-		return;
-
-	/*
-	 * phys_to_virt doesn't work with hihgmem page but we could
-	 * call dma_mark_clean() with hihgmem page here. However, we
-	 * are fine since dma_mark_clean() is null on POWERPC. We can
-	 * make dma_mark_clean() take a physical address if necessary.
-	 */
-	dma_mark_clean(phys_to_virt(paddr), size);
-}
-
-void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
-			size_t size, enum dma_data_direction dir,
-			unsigned long attrs)
-{
-	unmap_single(hwdev, dev_addr, size, dir, attrs);
-}
-
-/*
- * Make physical memory consistent for a single streaming mode DMA translation
- * after a transfer.
- *
- * If you perform a swiotlb_map_page() but wish to interrogate the buffer
- * using the cpu, yet do not wish to teardown the dma mapping, you must
- * call this function before doing so.  At the next point you give the dma
- * address back to the card, you must first perform a
- * swiotlb_dma_sync_for_device, and then the device again owns the buffer
- */
-static void
-swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
-		    size_t size, enum dma_data_direction dir,
-		    enum dma_sync_target target)
-{
-	phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
-
-	BUG_ON(dir == DMA_NONE);
-
-	if (is_swiotlb_buffer(paddr)) {
-		swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target);
-		return;
-	}
-
-	if (dir != DMA_FROM_DEVICE)
-		return;
-
-	dma_mark_clean(phys_to_virt(paddr), size);
-}
-
-void
-swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
-			    size_t size, enum dma_data_direction dir)
-{
-	swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
-}
-
-void
-swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
-			       size_t size, enum dma_data_direction dir)
-{
-	swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
-}
-
-/*
- * Map a set of buffers described by scatterlist in streaming mode for DMA.
- * This is the scatter-gather version of the above swiotlb_map_page
- * interface.  Here the scatter gather list elements are each tagged with the
- * appropriate dma address and length.  They are obtained via
- * sg_dma_{address,length}(SG).
- *
- * NOTE: An implementation may be able to use a smaller number of
- *       DMA address/length pairs than there are SG table elements.
- *       (for example via virtual mapping capabilities)
- *       The routine returns the number of addr/length pairs actually
- *       used, at most nents.
- *
- * Device ownership issues as mentioned above for swiotlb_map_page are the
- * same here.
- */
-int
-swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
-		     enum dma_data_direction dir, unsigned long attrs)
-{
-	struct scatterlist *sg;
-	int i;
-
-	BUG_ON(dir == DMA_NONE);
-
-	for_each_sg(sgl, sg, nelems, i) {
-		phys_addr_t paddr = sg_phys(sg);
-		dma_addr_t dev_addr = phys_to_dma(hwdev, paddr);
-
-		if (swiotlb_force == SWIOTLB_FORCE ||
-		    !dma_capable(hwdev, dev_addr, sg->length)) {
-			phys_addr_t map = map_single(hwdev, sg_phys(sg),
-						     sg->length, dir, attrs);
-			if (map == SWIOTLB_MAP_ERROR) {
-				/* Don't panic here, we expect map_sg users
-				   to do proper error handling. */
-				swiotlb_full(hwdev, sg->length, dir, 0);
-				attrs |= DMA_ATTR_SKIP_CPU_SYNC;
-				swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
-						       attrs);
-				sg_dma_len(sgl) = 0;
-				return 0;
-			}
-			sg->dma_address = __phys_to_dma(hwdev, map);
-		} else
-			sg->dma_address = dev_addr;
-		sg_dma_len(sg) = sg->length;
-	}
-	return nelems;
-}
-
-/*
- * Unmap a set of streaming mode DMA translations.  Again, cpu read rules
- * concerning calls here are the same as for swiotlb_unmap_page() above.
- */
-void
-swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
-		       int nelems, enum dma_data_direction dir,
-		       unsigned long attrs)
-{
-	struct scatterlist *sg;
-	int i;
-
-	BUG_ON(dir == DMA_NONE);
-
-	for_each_sg(sgl, sg, nelems, i)
-		unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir,
-			     attrs);
-}
-
-/*
- * Make physical memory consistent for a set of streaming mode DMA translations
- * after a transfer.
- *
- * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
- * and usage.
- */
-static void
-swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
-		int nelems, enum dma_data_direction dir,
-		enum dma_sync_target target)
-{
-	struct scatterlist *sg;
-	int i;
-
-	for_each_sg(sgl, sg, nelems, i)
-		swiotlb_sync_single(hwdev, sg->dma_address,
-				    sg_dma_len(sg), dir, target);
-}
-
-void
-swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
-			int nelems, enum dma_data_direction dir)
-{
-	swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
-}
-
-void
-swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
-			   int nelems, enum dma_data_direction dir)
-{
-	swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
-}
-
-int
-swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
-{
-	return (dma_addr == __phys_to_dma(hwdev, io_tlb_overflow_buffer));
-}
-
-/*
- * Return whether the given device DMA address mask can be supported
- * properly.  For example, if your device can only drive the low 24-bits
- * during bus mastering, then you would pass 0x00ffffff as the mask to
- * this function.
- */
-int
-swiotlb_dma_supported(struct device *hwdev, u64 mask)
-{
-	return __phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
-}
-
-void *swiotlb_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
-		gfp_t gfp, unsigned long attrs)
-{
-	void *vaddr;
-
-	/* temporary workaround: */
-	if (gfp & __GFP_NOWARN)
-		attrs |= DMA_ATTR_NO_WARN;
-
-	/*
-	 * Don't print a warning when the first allocation attempt fails.
-	 * swiotlb_alloc_coherent() will print a warning when the DMA memory
-	 * allocation ultimately failed.
-	 */
-	gfp |= __GFP_NOWARN;
-
-	vaddr = dma_direct_alloc(dev, size, dma_handle, gfp, attrs);
-	if (!vaddr)
-		vaddr = swiotlb_alloc_buffer(dev, size, dma_handle, attrs);
-	return vaddr;
-}
-
-void swiotlb_free(struct device *dev, size_t size, void *vaddr,
-		dma_addr_t dma_addr, unsigned long attrs)
-{
-	if (!swiotlb_free_buffer(dev, size, dma_addr))
-		dma_direct_free(dev, size, vaddr, dma_addr, attrs);
-}
-
-const struct dma_map_ops swiotlb_dma_ops = {
-	.mapping_error		= swiotlb_dma_mapping_error,
-	.alloc			= swiotlb_alloc,
-	.free			= swiotlb_free,
-	.sync_single_for_cpu	= swiotlb_sync_single_for_cpu,
-	.sync_single_for_device	= swiotlb_sync_single_for_device,
-	.sync_sg_for_cpu	= swiotlb_sync_sg_for_cpu,
-	.sync_sg_for_device	= swiotlb_sync_sg_for_device,
-	.map_sg			= swiotlb_map_sg_attrs,
-	.unmap_sg		= swiotlb_unmap_sg_attrs,
-	.map_page		= swiotlb_map_page,
-	.unmap_page		= swiotlb_unmap_page,
-	.dma_supported		= dma_direct_supported,
-};