2 * Dynamic DMA mapping support.
4 * This implementation is a fallback for platforms that do not support
5 * I/O TLBs (aka DMA address translation hardware).
6 * Copyright (C) 2000 Asit Mallick <Asit.K.Mallick@intel.com>
7 * Copyright (C) 2000 Goutham Rao <goutham.rao@intel.com>
8 * Copyright (C) 2000, 2003 Hewlett-Packard Co
9 * David Mosberger-Tang <davidm@hpl.hp.com>
10 * Copyright (C) 2005 Keir Fraser <keir@xensource.com>
11 * 08/12/11 beckyb Add highmem support
14 #include <linux/cache.h>
16 #include <linux/export.h>
17 #include <linux/pci.h>
18 #include <linux/spinlock.h>
19 #include <linux/string.h>
20 #include <linux/swiotlb.h>
21 #include <linux/pfn.h>
22 #include <linux/types.h>
23 #include <linux/ctype.h>
24 #include <linux/init.h>
25 #include <linux/bootmem.h>
26 #include <linux/iommu-helper.h>
27 #include <linux/highmem.h>
28 #include <linux/gfp.h>
33 #include <asm/uaccess.h>
34 #include <xen/gnttab.h>
35 #include <xen/interface/memory.h>
36 #include <asm/gnttab_dma.h>
38 #define OFFSET(val,align) ((unsigned long)((val) & ( (align) - 1)))
44 * Used to do a quick range check in swiotlb_tbl_unmap_single and
45 * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
48 static char *io_tlb_start, *io_tlb_end;
51 * The number of IO TLB blocks (in groups of 64) between io_tlb_start and
52 * io_tlb_end. This is command line adjustable via setup_io_tlb_npages.
54 static unsigned long io_tlb_nslabs;
57 * When the IOMMU overflows we return a fallback buffer. This sets the size.
59 static unsigned long io_tlb_overflow = 32*1024;
61 static void *io_tlb_overflow_buffer;
64 * This is a free list describing the number of free entries available from
67 static unsigned int *io_tlb_list;
68 static unsigned int io_tlb_index;
71 * We need to save away the original address corresponding to a mapped entry
72 * for the sync operations.
74 static phys_addr_t *io_tlb_orig_addr;
77 * Protect the above data structures in the map and unmap calls
79 static DEFINE_SPINLOCK(io_tlb_lock);
81 static unsigned int dma_bits;
82 static unsigned int __initdata max_dma_bits = 32;
84 setup_dma_bits(char *str)
86 max_dma_bits = simple_strtoul(str, NULL, 0);
89 __setup("dma_bits=", setup_dma_bits);
92 setup_io_tlb_npages(char *str)
94 /* Unlike ia64, the size is aperture in megabytes, not 'slabs'! */
96 io_tlb_nslabs = simple_strtoul(str, &str, 0) <<
98 io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
103 * NB. 'force' enables the swiotlb, but doesn't force its use for
104 * every DMA like it does on native Linux. 'off' forcibly disables
105 * use of the swiotlb.
107 if (!strcmp(str, "force"))
109 else if (!strcmp(str, "off"))
114 __setup("swiotlb=", setup_io_tlb_npages);
115 /* make io_tlb_overflow tunable too? */
117 unsigned long swiotlb_nr_tbl(void)
119 return io_tlb_nslabs;
121 EXPORT_SYMBOL_GPL(swiotlb_nr_tbl);
122 /* Note that this doesn't work with highmem page */
123 static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
124 volatile void *address)
126 return phys_to_dma(hwdev, virt_to_phys(address));
129 void swiotlb_print_info(void)
131 unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;
133 printk(KERN_INFO "Software IO TLB enabled: \n"
134 " Aperture: %lu megabytes\n"
135 " Address size: %u bits\n"
136 " Kernel range: %p - %p\n",
137 bytes >> 20, dma_bits,
138 io_tlb_start, io_tlb_end);
141 void __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
143 unsigned long i, bytes;
146 bytes = nslabs << IO_TLB_SHIFT;
148 io_tlb_nslabs = nslabs;
150 dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
151 for (nslabs = 0; nslabs < io_tlb_nslabs; nslabs += IO_TLB_SEGSIZE) {
153 rc = xen_create_contiguous_region(
154 (unsigned long)io_tlb_start + (nslabs << IO_TLB_SHIFT),
155 get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT),
157 } while (rc && dma_bits++ < max_dma_bits);
160 panic("No suitable physical memory available for SWIOTLB buffer!\n"
161 "Use dom0_mem Xen boot parameter to reserve\n"
162 "some DMA memory (e.g., dom0_mem=-128M).\n");
163 io_tlb_nslabs = nslabs;
164 i = nslabs << IO_TLB_SHIFT;
165 free_bootmem(__pa(io_tlb_start + i), bytes - i);
167 for (dma_bits = 0; i > 0; i -= IO_TLB_SEGSIZE << IO_TLB_SHIFT) {
168 unsigned int bits = fls64(virt_to_bus(io_tlb_start + i - 1));
176 io_tlb_end = io_tlb_start + bytes;
179 * Allocate and initialize the free list array. This array is used
180 * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE.
182 io_tlb_list = alloc_bootmem_pages(PAGE_ALIGN(io_tlb_nslabs * sizeof(int)));
183 for (i = 0; i < io_tlb_nslabs; i++)
184 io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
186 io_tlb_orig_addr = alloc_bootmem_pages(PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
189 * Get the overflow emergency buffer
191 io_tlb_overflow_buffer = alloc_bootmem_pages(PAGE_ALIGN(io_tlb_overflow));
192 if (!io_tlb_overflow_buffer)
193 panic("Cannot allocate SWIOTLB overflow buffer!\n");
196 rc = xen_create_contiguous_region(
197 (unsigned long)io_tlb_overflow_buffer,
198 get_order(io_tlb_overflow),
200 } while (rc && dma_bits++ < max_dma_bits);
202 panic("No suitable physical memory available for SWIOTLB overflow buffer!\n");
204 swiotlb_print_info();
208 * Statically reserve bounce buffer space and initialize bounce buffer data
209 * structures for the software IO TLB used to implement the DMA API.
212 swiotlb_init_with_default_size(size_t default_size, int verbose)
216 if (!io_tlb_nslabs) {
217 io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
218 io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
221 bytes = io_tlb_nslabs << IO_TLB_SHIFT;
224 * Get IO TLB memory from the low pages
226 io_tlb_start = alloc_bootmem_pages(PAGE_ALIGN(bytes));
228 panic("Cannot allocate SWIOTLB buffer");
230 swiotlb_init_with_tbl(io_tlb_start, io_tlb_nslabs, verbose);
234 swiotlb_init(int verbose)
236 unsigned long ram_end;
237 size_t defsz = 64 << 20; /* 64MB default size */
239 if (swiotlb_force == 1) {
241 } else if ((swiotlb_force != -1) &&
242 is_running_on_xen() &&
243 is_initial_xendomain()) {
244 /* Domain 0 always has a swiotlb. */
245 ram_end = HYPERVISOR_memory_op(XENMEM_maximum_ram_page, NULL);
246 if (ram_end <= 0x1ffff)
247 defsz = 2 << 20; /* 2MB on <512MB systems. */
248 else if (ram_end <= 0x3ffff)
249 defsz = 4 << 20; /* 4MB on <1GB systems. */
250 else if (ram_end <= 0x7ffff)
251 defsz = 8 << 20; /* 8MB on <2GB systems. */
256 swiotlb_init_with_default_size(defsz, verbose);
258 printk(KERN_INFO "Software IO TLB disabled\n");
261 static inline int range_needs_mapping(phys_addr_t pa, size_t size)
263 return range_straddles_page_boundary(pa, size);
266 static int is_swiotlb_buffer(dma_addr_t addr)
268 unsigned long pfn = mfn_to_local_pfn(PFN_DOWN(addr));
269 phys_addr_t paddr = (phys_addr_t)pfn << PAGE_SHIFT;
271 return paddr >= virt_to_phys(io_tlb_start) &&
272 paddr < virt_to_phys(io_tlb_end);
276 * Bounce: copy the swiotlb buffer back to the original dma location
278 * We use __copy_to_user_inatomic to transfer to the host buffer because the
279 * buffer may be mapped read-only (e.g, in blkback driver) but lower-level
280 * drivers map the buffer for DMA_BIDIRECTIONAL access. This causes an
281 * unnecessary copy from the aperture to the host buffer, and a page fault.
283 void swiotlb_bounce(phys_addr_t phys, char *dma_addr, size_t size,
284 enum dma_data_direction dir)
286 unsigned long pfn = PFN_DOWN(phys);
288 if (PageHighMem(pfn_to_page(pfn))) {
289 /* The buffer does not have a mapping. Map it in and copy */
290 unsigned int offset = phys & ~PAGE_MASK;
296 sz = min_t(size_t, PAGE_SIZE - offset, size);
298 local_irq_save(flags);
299 buffer = kmap_atomic(pfn_to_page(pfn));
300 if (dir == DMA_TO_DEVICE)
301 memcpy(dma_addr, buffer + offset, sz);
302 else if (__copy_to_user_inatomic(buffer + offset,
305 kunmap_atomic(buffer);
306 local_irq_restore(flags);
314 if (dir == DMA_TO_DEVICE)
315 memcpy(dma_addr, phys_to_virt(phys), size);
316 else if (__copy_to_user_inatomic(phys_to_virt(phys),
321 EXPORT_SYMBOL_GPL(swiotlb_bounce);
323 void *swiotlb_tbl_map_single(struct device *hwdev, dma_addr_t tbl_dma_addr,
324 phys_addr_t phys, size_t size,
325 enum dma_data_direction dir)
329 unsigned int nslots, stride, index, wrap;
332 unsigned long offset_slots;
333 unsigned long max_slots;
335 mask = dma_get_seg_boundary(hwdev);
336 offset_slots = -IO_TLB_SEGSIZE;
339 * Carefully handle integer overflow which can occur when mask == ~0UL.
342 ? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT
343 : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
346 * For mappings greater than a page, we limit the stride (and
347 * hence alignment) to a page size.
349 nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
350 if (size > PAGE_SIZE)
351 stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
358 * Find suitable number of IO TLB entries size that will fit this
359 * request and allocate a buffer from that IO TLB pool.
361 spin_lock_irqsave(&io_tlb_lock, flags);
362 index = ALIGN(io_tlb_index, stride);
363 if (index >= io_tlb_nslabs)
368 while (iommu_is_span_boundary(index, nslots, offset_slots,
371 if (index >= io_tlb_nslabs)
378 * If we find a slot that indicates we have 'nslots' number of
379 * contiguous buffers, we allocate the buffers from that slot
380 * and mark the entries as '0' indicating unavailable.
382 if (io_tlb_list[index] >= nslots) {
385 for (i = index; i < (int) (index + nslots); i++)
387 for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) && io_tlb_list[i]; i--)
388 io_tlb_list[i] = ++count;
389 dma_addr = io_tlb_start + (index << IO_TLB_SHIFT);
392 * Update the indices to avoid searching in the next
395 io_tlb_index = ((index + nslots) < io_tlb_nslabs
396 ? (index + nslots) : 0);
401 if (index >= io_tlb_nslabs)
403 } while (index != wrap);
406 spin_unlock_irqrestore(&io_tlb_lock, flags);
409 spin_unlock_irqrestore(&io_tlb_lock, flags);
412 * Save away the mapping from the original address to the DMA address.
413 * This is needed when we sync the memory. Then we sync the buffer if
416 for (i = 0; i < nslots; i++)
417 io_tlb_orig_addr[index+i] = phys + (i << IO_TLB_SHIFT);
418 if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
419 swiotlb_bounce(phys, dma_addr, size, DMA_TO_DEVICE);
423 EXPORT_SYMBOL_GPL(swiotlb_tbl_map_single);
426 * Allocates bounce buffer and returns its kernel virtual address.
430 map_single(struct device *hwdev, phys_addr_t phys, size_t size,
431 enum dma_data_direction dir)
433 dma_addr_t start_dma_addr = swiotlb_virt_to_bus(hwdev, io_tlb_start);
435 return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, dir);
439 * dma_addr is the kernel virtual address of the bounce buffer to unmap.
442 swiotlb_tbl_unmap_single(struct device *hwdev, char *dma_addr, size_t size,
443 enum dma_data_direction dir)
446 int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
447 int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
448 phys_addr_t phys = io_tlb_orig_addr[index];
451 * First, sync the memory before unmapping the entry
453 if (phys && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
454 swiotlb_bounce(phys, dma_addr, size, DMA_FROM_DEVICE);
457 * Return the buffer to the free list by setting the corresponding
458 * entries to indicate the number of contiguous entries available.
459 * While returning the entries to the free list, we merge the entries
460 * with slots below and above the pool being returned.
462 spin_lock_irqsave(&io_tlb_lock, flags);
464 count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
465 io_tlb_list[index + nslots] : 0);
467 * Step 1: return the slots to the free list, merging the
468 * slots with superceeding slots
470 for (i = index + nslots - 1; i >= index; i--)
471 io_tlb_list[i] = ++count;
473 * Step 2: merge the returned slots with the preceding slots,
474 * if available (non zero)
477 (OFFSET(i, IO_TLB_SEGSIZE) !=
478 IO_TLB_SEGSIZE -1) && io_tlb_list[i];
480 io_tlb_list[i] = ++count;
482 spin_unlock_irqrestore(&io_tlb_lock, flags);
484 EXPORT_SYMBOL_GPL(swiotlb_tbl_unmap_single);
487 swiotlb_tbl_sync_single(struct device *hwdev, char *dma_addr, size_t size,
488 enum dma_data_direction dir,
489 enum dma_sync_target target)
491 int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
492 phys_addr_t phys = io_tlb_orig_addr[index];
494 phys += ((unsigned long)dma_addr & ((1 << IO_TLB_SHIFT) - 1));
498 if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
499 swiotlb_bounce(phys, dma_addr, size, DMA_FROM_DEVICE);
501 BUG_ON(dir != DMA_TO_DEVICE);
503 case SYNC_FOR_DEVICE:
504 if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
505 swiotlb_bounce(phys, dma_addr, size, DMA_TO_DEVICE);
507 BUG_ON(dir != DMA_FROM_DEVICE);
513 EXPORT_SYMBOL_GPL(swiotlb_tbl_sync_single);
516 swiotlb_full(struct device *dev, size_t size, enum dma_data_direction dir,
520 * Ran out of IOMMU space for this operation. This is very bad.
521 * Unfortunately the drivers cannot handle this operation properly.
522 * unless they check for pci_dma_mapping_error (most don't)
523 * When the mapping is small enough return a static buffer to limit
524 * the damage, or panic when the transfer is too big.
526 printk(KERN_ERR "PCI-DMA: Out of SW-IOMMU space for %zu bytes at "
527 "device %s\n", size, dev ? dev_name(dev) : "?");
529 if (size <= io_tlb_overflow || !do_panic)
532 if (dir == DMA_BIDIRECTIONAL)
533 panic("DMA: Random memory could be DMA accessed\n");
534 if (dir == DMA_FROM_DEVICE)
535 panic("DMA: Random memory could be DMA written\n");
536 if (dir == DMA_TO_DEVICE)
537 panic("DMA: Random memory could be DMA read\n");
541 * Map a single buffer of the indicated size for DMA in streaming mode. The
542 * PCI address to use is returned.
544 * Once the device is given the dma address, the device owns this memory until
545 * either swiotlb_unmap_page or swiotlb_dma_sync_single is performed.
547 dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
548 unsigned long offset, size_t size,
549 enum dma_data_direction dir,
550 struct dma_attrs *attrs)
552 phys_addr_t phys = page_to_pseudophys(page) + offset;
553 dma_addr_t dev_addr = gnttab_dma_map_page(page) + offset;
556 BUG_ON(dir == DMA_NONE);
559 * If the address happens to be in the device's DMA window,
560 * we can safely return the device addr and not worry about bounce
563 if (dma_capable(dev, dev_addr, size) &&
564 !range_needs_mapping(phys, size))
568 * Oh well, have to allocate and map a bounce buffer.
570 gnttab_dma_unmap_page(dev_addr);
571 map = map_single(dev, phys, size, dir);
573 swiotlb_full(dev, size, dir, 1);
574 map = io_tlb_overflow_buffer;
577 dev_addr = swiotlb_virt_to_bus(dev, map);
580 * Ensure that the address returned is DMA'ble
582 if (!dma_capable(dev, dev_addr, size)) {
583 swiotlb_tbl_unmap_single(dev, map, size, dir);
584 dev_addr = swiotlb_virt_to_bus(dev, io_tlb_overflow_buffer);
589 EXPORT_SYMBOL_GPL(swiotlb_map_page);
592 * Unmap a single streaming mode DMA translation. The dma_addr and size must
593 * match what was provided for in a previous swiotlb_map_page call. All
594 * other usages are undefined.
596 * After this call, reads by the cpu to the buffer are guaranteed to see
597 * whatever the device wrote there.
599 static void unmap_single(struct device *hwdev, dma_addr_t dev_addr,
600 size_t size, enum dma_data_direction dir)
602 phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
604 BUG_ON(dir == DMA_NONE);
606 if (is_swiotlb_buffer(dev_addr)) {
607 swiotlb_tbl_unmap_single(hwdev, phys_to_virt(paddr), size, dir);
611 gnttab_dma_unmap_page(dev_addr);
614 void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
615 size_t size, enum dma_data_direction dir,
616 struct dma_attrs *attrs)
618 unmap_single(hwdev, dev_addr, size, dir);
620 EXPORT_SYMBOL_GPL(swiotlb_unmap_page);
623 * Make physical memory consistent for a single streaming mode DMA translation
626 * If you perform a swiotlb_map_page() but wish to interrogate the buffer
627 * using the cpu, yet do not wish to teardown the PCI dma mapping, you must
628 * call this function before doing so. At the next point you give the PCI dma
629 * address back to the card, you must first perform a
630 * swiotlb_dma_sync_for_device, and then the device again owns the buffer
633 swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
634 size_t size, enum dma_data_direction dir,
635 enum dma_sync_target target)
637 phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
639 BUG_ON(dir == DMA_NONE);
641 if (is_swiotlb_buffer(dev_addr))
642 swiotlb_tbl_sync_single(hwdev, phys_to_virt(paddr), size, dir,
647 swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
648 size_t size, enum dma_data_direction dir)
650 swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
652 EXPORT_SYMBOL(swiotlb_sync_single_for_cpu);
655 swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
656 size_t size, enum dma_data_direction dir)
658 swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
660 EXPORT_SYMBOL(swiotlb_sync_single_for_device);
663 * Map a set of buffers described by scatterlist in streaming mode for DMA.
664 * This is the scatter-gather version of the above swiotlb_map_page
665 * interface. Here the scatter gather list elements are each tagged with the
666 * appropriate dma address and length. They are obtained via
667 * sg_dma_{address,length}(SG).
669 * NOTE: An implementation may be able to use a smaller number of
670 * DMA address/length pairs than there are SG table elements.
671 * (for example via virtual mapping capabilities)
672 * The routine returns the number of addr/length pairs actually
673 * used, at most nents.
675 * Device ownership issues as mentioned above for swiotlb_map_page are the
679 swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
680 enum dma_data_direction dir, struct dma_attrs *attrs)
682 struct scatterlist *sg;
685 BUG_ON(dir == DMA_NONE);
687 for_each_sg(sgl, sg, nelems, i) {
688 dma_addr_t dev_addr = gnttab_dma_map_page(sg_page(sg))
690 phys_addr_t paddr = page_to_pseudophys(sg_page(sg))
693 if (range_needs_mapping(paddr, sg->length) ||
694 !dma_capable(hwdev, dev_addr, sg->length)) {
697 gnttab_dma_unmap_page(dev_addr);
698 map = map_single(hwdev, paddr,
701 /* Don't panic here, we expect map_sg users
702 to do proper error handling. */
703 swiotlb_full(hwdev, sg->length, dir, 0);
704 swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
706 sgl[0].dma_length = 0;
709 sg->dma_address = swiotlb_virt_to_bus(hwdev, map);
711 sg->dma_address = dev_addr;
712 sg->dma_length = sg->length;
716 EXPORT_SYMBOL(swiotlb_map_sg_attrs);
719 swiotlb_map_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
720 enum dma_data_direction dir)
722 return swiotlb_map_sg_attrs(hwdev, sgl, nelems, dir, NULL);
724 EXPORT_SYMBOL(swiotlb_map_sg);
727 * Unmap a set of streaming mode DMA translations. Again, cpu read rules
728 * concerning calls here are the same as for swiotlb_unmap_page() above.
731 swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
732 int nelems, enum dma_data_direction dir, struct dma_attrs *attrs)
734 struct scatterlist *sg;
737 BUG_ON(dir == DMA_NONE);
739 for_each_sg(sgl, sg, nelems, i)
740 unmap_single(hwdev, sg->dma_address, sg->dma_length, dir);
743 EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);
746 swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
747 enum dma_data_direction dir)
749 return swiotlb_unmap_sg_attrs(hwdev, sgl, nelems, dir, NULL);
751 EXPORT_SYMBOL(swiotlb_unmap_sg);
754 * Make physical memory consistent for a set of streaming mode DMA translations
757 * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
761 swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
762 int nelems, enum dma_data_direction dir,
763 enum dma_sync_target target)
765 struct scatterlist *sg;
768 for_each_sg(sgl, sg, nelems, i)
769 swiotlb_sync_single(hwdev, sg->dma_address,
770 sg->dma_length, dir, target);
774 swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
775 int nelems, enum dma_data_direction dir)
777 swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
779 EXPORT_SYMBOL(swiotlb_sync_sg_for_cpu);
782 swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
783 int nelems, enum dma_data_direction dir)
785 swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
787 EXPORT_SYMBOL(swiotlb_sync_sg_for_device);
790 swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
792 return (dma_addr == swiotlb_virt_to_bus(hwdev, io_tlb_overflow_buffer));
794 EXPORT_SYMBOL(swiotlb_dma_mapping_error);
797 * Return whether the given PCI device DMA address mask can be supported
798 * properly. For example, if your device can only drive the low 24-bits
799 * during PCI bus mastering, then you would pass 0x00ffffff as the mask to
803 swiotlb_dma_supported (struct device *hwdev, u64 mask)
805 return (mask >= ((1UL << dma_bits) - 1));
807 EXPORT_SYMBOL(swiotlb_dma_supported);