Version:  2.6.34 2.6.35 2.6.36 2.6.37 2.6.38 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14

Linux/lib/swiotlb.c

  1 /*
  2  * Dynamic DMA mapping support.
  3  *
  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  *
 11  * 03/05/07 davidm      Switch from PCI-DMA to generic device DMA API.
 12  * 00/12/13 davidm      Rename to swiotlb.c and add mark_clean() to avoid
 13  *                      unnecessary i-cache flushing.
 14  * 04/07/.. ak          Better overflow handling. Assorted fixes.
 15  * 05/09/10 linville    Add support for syncing ranges, support syncing for
 16  *                      DMA_BIDIRECTIONAL mappings, miscellaneous cleanup.
 17  * 08/12/11 beckyb      Add highmem support
 18  */
 19 
 20 #include <linux/cache.h>
 21 #include <linux/dma-mapping.h>
 22 #include <linux/mm.h>
 23 #include <linux/export.h>
 24 #include <linux/spinlock.h>
 25 #include <linux/string.h>
 26 #include <linux/swiotlb.h>
 27 #include <linux/pfn.h>
 28 #include <linux/types.h>
 29 #include <linux/ctype.h>
 30 #include <linux/highmem.h>
 31 #include <linux/gfp.h>
 32 
 33 #include <asm/io.h>
 34 #include <asm/dma.h>
 35 #include <asm/scatterlist.h>
 36 
 37 #include <linux/init.h>
 38 #include <linux/bootmem.h>
 39 #include <linux/iommu-helper.h>
 40 
 41 #define CREATE_TRACE_POINTS
 42 #include <trace/events/swiotlb.h>
 43 
 44 #define OFFSET(val,align) ((unsigned long)      \
 45                            ( (val) & ( (align) - 1)))
 46 
 47 #define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
 48 
 49 /*
 50  * Minimum IO TLB size to bother booting with.  Systems with mainly
 51  * 64bit capable cards will only lightly use the swiotlb.  If we can't
 52  * allocate a contiguous 1MB, we're probably in trouble anyway.
 53  */
 54 #define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
 55 
 56 int swiotlb_force;
 57 
 58 /*
 59  * Used to do a quick range check in swiotlb_tbl_unmap_single and
 60  * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
 61  * API.
 62  */
 63 static phys_addr_t io_tlb_start, io_tlb_end;
 64 
 65 /*
 66  * The number of IO TLB blocks (in groups of 64) between io_tlb_start and
 67  * io_tlb_end.  This is command line adjustable via setup_io_tlb_npages.
 68  */
 69 static unsigned long io_tlb_nslabs;
 70 
 71 /*
 72  * When the IOMMU overflows we return a fallback buffer. This sets the size.
 73  */
 74 static unsigned long io_tlb_overflow = 32*1024;
 75 
 76 static phys_addr_t io_tlb_overflow_buffer;
 77 
 78 /*
 79  * This is a free list describing the number of free entries available from
 80  * each index
 81  */
 82 static unsigned int *io_tlb_list;
 83 static unsigned int io_tlb_index;
 84 
 85 /*
 86  * We need to save away the original address corresponding to a mapped entry
 87  * for the sync operations.
 88  */
 89 static phys_addr_t *io_tlb_orig_addr;
 90 
 91 /*
 92  * Protect the above data structures in the map and unmap calls
 93  */
 94 static DEFINE_SPINLOCK(io_tlb_lock);
 95 
 96 static int late_alloc;
 97 
 98 static int __init
 99 setup_io_tlb_npages(char *str)
100 {
101         if (isdigit(*str)) {
102                 io_tlb_nslabs = simple_strtoul(str, &str, 0);
103                 /* avoid tail segment of size < IO_TLB_SEGSIZE */
104                 io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
105         }
106         if (*str == ',')
107                 ++str;
108         if (!strcmp(str, "force"))
109                 swiotlb_force = 1;
110 
111         return 0;
112 }
113 early_param("swiotlb", setup_io_tlb_npages);
114 /* make io_tlb_overflow tunable too? */
115 
116 unsigned long swiotlb_nr_tbl(void)
117 {
118         return io_tlb_nslabs;
119 }
120 EXPORT_SYMBOL_GPL(swiotlb_nr_tbl);
121 
122 /* default to 64MB */
123 #define IO_TLB_DEFAULT_SIZE (64UL<<20)
124 unsigned long swiotlb_size_or_default(void)
125 {
126         unsigned long size;
127 
128         size = io_tlb_nslabs << IO_TLB_SHIFT;
129 
130         return size ? size : (IO_TLB_DEFAULT_SIZE);
131 }
132 
133 /* Note that this doesn't work with highmem page */
134 static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
135                                       volatile void *address)
136 {
137         return phys_to_dma(hwdev, virt_to_phys(address));
138 }
139 
140 static bool no_iotlb_memory;
141 
142 void swiotlb_print_info(void)
143 {
144         unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;
145         unsigned char *vstart, *vend;
146 
147         if (no_iotlb_memory) {
148                 pr_warn("software IO TLB: No low mem\n");
149                 return;
150         }
151 
152         vstart = phys_to_virt(io_tlb_start);
153         vend = phys_to_virt(io_tlb_end);
154 
155         printk(KERN_INFO "software IO TLB [mem %#010llx-%#010llx] (%luMB) mapped at [%p-%p]\n",
156                (unsigned long long)io_tlb_start,
157                (unsigned long long)io_tlb_end,
158                bytes >> 20, vstart, vend - 1);
159 }
160 
161 int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
162 {
163         void *v_overflow_buffer;
164         unsigned long i, bytes;
165 
166         bytes = nslabs << IO_TLB_SHIFT;
167 
168         io_tlb_nslabs = nslabs;
169         io_tlb_start = __pa(tlb);
170         io_tlb_end = io_tlb_start + bytes;
171 
172         /*
173          * Get the overflow emergency buffer
174          */
175         v_overflow_buffer = memblock_virt_alloc_low_nopanic(
176                                                 PAGE_ALIGN(io_tlb_overflow),
177                                                 PAGE_SIZE);
178         if (!v_overflow_buffer)
179                 return -ENOMEM;
180 
181         io_tlb_overflow_buffer = __pa(v_overflow_buffer);
182 
183         /*
184          * Allocate and initialize the free list array.  This array is used
185          * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
186          * between io_tlb_start and io_tlb_end.
187          */
188         io_tlb_list = memblock_virt_alloc(
189                                 PAGE_ALIGN(io_tlb_nslabs * sizeof(int)),
190                                 PAGE_SIZE);
191         for (i = 0; i < io_tlb_nslabs; i++)
192                 io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
193         io_tlb_index = 0;
194         io_tlb_orig_addr = memblock_virt_alloc(
195                                 PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)),
196                                 PAGE_SIZE);
197 
198         if (verbose)
199                 swiotlb_print_info();
200 
201         return 0;
202 }
203 
204 /*
205  * Statically reserve bounce buffer space and initialize bounce buffer data
206  * structures for the software IO TLB used to implement the DMA API.
207  */
208 void  __init
209 swiotlb_init(int verbose)
210 {
211         size_t default_size = IO_TLB_DEFAULT_SIZE;
212         unsigned char *vstart;
213         unsigned long bytes;
214 
215         if (!io_tlb_nslabs) {
216                 io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
217                 io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
218         }
219 
220         bytes = io_tlb_nslabs << IO_TLB_SHIFT;
221 
222         /* Get IO TLB memory from the low pages */
223         vstart = memblock_virt_alloc_low_nopanic(PAGE_ALIGN(bytes), PAGE_SIZE);
224         if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose))
225                 return;
226 
227         if (io_tlb_start)
228                 memblock_free_early(io_tlb_start,
229                                     PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
230         pr_warn("Cannot allocate SWIOTLB buffer");
231         no_iotlb_memory = true;
232 }
233 
234 /*
235  * Systems with larger DMA zones (those that don't support ISA) can
236  * initialize the swiotlb later using the slab allocator if needed.
237  * This should be just like above, but with some error catching.
238  */
239 int
240 swiotlb_late_init_with_default_size(size_t default_size)
241 {
242         unsigned long bytes, req_nslabs = io_tlb_nslabs;
243         unsigned char *vstart = NULL;
244         unsigned int order;
245         int rc = 0;
246 
247         if (!io_tlb_nslabs) {
248                 io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
249                 io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
250         }
251 
252         /*
253          * Get IO TLB memory from the low pages
254          */
255         order = get_order(io_tlb_nslabs << IO_TLB_SHIFT);
256         io_tlb_nslabs = SLABS_PER_PAGE << order;
257         bytes = io_tlb_nslabs << IO_TLB_SHIFT;
258 
259         while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
260                 vstart = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
261                                                   order);
262                 if (vstart)
263                         break;
264                 order--;
265         }
266 
267         if (!vstart) {
268                 io_tlb_nslabs = req_nslabs;
269                 return -ENOMEM;
270         }
271         if (order != get_order(bytes)) {
272                 printk(KERN_WARNING "Warning: only able to allocate %ld MB "
273                        "for software IO TLB\n", (PAGE_SIZE << order) >> 20);
274                 io_tlb_nslabs = SLABS_PER_PAGE << order;
275         }
276         rc = swiotlb_late_init_with_tbl(vstart, io_tlb_nslabs);
277         if (rc)
278                 free_pages((unsigned long)vstart, order);
279         return rc;
280 }
281 
282 int
283 swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
284 {
285         unsigned long i, bytes;
286         unsigned char *v_overflow_buffer;
287 
288         bytes = nslabs << IO_TLB_SHIFT;
289 
290         io_tlb_nslabs = nslabs;
291         io_tlb_start = virt_to_phys(tlb);
292         io_tlb_end = io_tlb_start + bytes;
293 
294         memset(tlb, 0, bytes);
295 
296         /*
297          * Get the overflow emergency buffer
298          */
299         v_overflow_buffer = (void *)__get_free_pages(GFP_DMA,
300                                                      get_order(io_tlb_overflow));
301         if (!v_overflow_buffer)
302                 goto cleanup2;
303 
304         io_tlb_overflow_buffer = virt_to_phys(v_overflow_buffer);
305 
306         /*
307          * Allocate and initialize the free list array.  This array is used
308          * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
309          * between io_tlb_start and io_tlb_end.
310          */
311         io_tlb_list = (unsigned int *)__get_free_pages(GFP_KERNEL,
312                                       get_order(io_tlb_nslabs * sizeof(int)));
313         if (!io_tlb_list)
314                 goto cleanup3;
315 
316         for (i = 0; i < io_tlb_nslabs; i++)
317                 io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
318         io_tlb_index = 0;
319 
320         io_tlb_orig_addr = (phys_addr_t *)
321                 __get_free_pages(GFP_KERNEL,
322                                  get_order(io_tlb_nslabs *
323                                            sizeof(phys_addr_t)));
324         if (!io_tlb_orig_addr)
325                 goto cleanup4;
326 
327         memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(phys_addr_t));
328 
329         swiotlb_print_info();
330 
331         late_alloc = 1;
332 
333         return 0;
334 
335 cleanup4:
336         free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
337                                                          sizeof(int)));
338         io_tlb_list = NULL;
339 cleanup3:
340         free_pages((unsigned long)v_overflow_buffer,
341                    get_order(io_tlb_overflow));
342         io_tlb_overflow_buffer = 0;
343 cleanup2:
344         io_tlb_end = 0;
345         io_tlb_start = 0;
346         io_tlb_nslabs = 0;
347         return -ENOMEM;
348 }
349 
350 void __init swiotlb_free(void)
351 {
352         if (!io_tlb_orig_addr)
353                 return;
354 
355         if (late_alloc) {
356                 free_pages((unsigned long)phys_to_virt(io_tlb_overflow_buffer),
357                            get_order(io_tlb_overflow));
358                 free_pages((unsigned long)io_tlb_orig_addr,
359                            get_order(io_tlb_nslabs * sizeof(phys_addr_t)));
360                 free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
361                                                                  sizeof(int)));
362                 free_pages((unsigned long)phys_to_virt(io_tlb_start),
363                            get_order(io_tlb_nslabs << IO_TLB_SHIFT));
364         } else {
365                 memblock_free_late(io_tlb_overflow_buffer,
366                                    PAGE_ALIGN(io_tlb_overflow));
367                 memblock_free_late(__pa(io_tlb_orig_addr),
368                                    PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
369                 memblock_free_late(__pa(io_tlb_list),
370                                    PAGE_ALIGN(io_tlb_nslabs * sizeof(int)));
371                 memblock_free_late(io_tlb_start,
372                                    PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
373         }
374         io_tlb_nslabs = 0;
375 }
376 
377 static int is_swiotlb_buffer(phys_addr_t paddr)
378 {
379         return paddr >= io_tlb_start && paddr < io_tlb_end;
380 }
381 
382 /*
383  * Bounce: copy the swiotlb buffer back to the original dma location
384  */
385 static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
386                            size_t size, enum dma_data_direction dir)
387 {
388         unsigned long pfn = PFN_DOWN(orig_addr);
389         unsigned char *vaddr = phys_to_virt(tlb_addr);
390 
391         if (PageHighMem(pfn_to_page(pfn))) {
392                 /* The buffer does not have a mapping.  Map it in and copy */
393                 unsigned int offset = orig_addr & ~PAGE_MASK;
394                 char *buffer;
395                 unsigned int sz = 0;
396                 unsigned long flags;
397 
398                 while (size) {
399                         sz = min_t(size_t, PAGE_SIZE - offset, size);
400 
401                         local_irq_save(flags);
402                         buffer = kmap_atomic(pfn_to_page(pfn));
403                         if (dir == DMA_TO_DEVICE)
404                                 memcpy(vaddr, buffer + offset, sz);
405                         else
406                                 memcpy(buffer + offset, vaddr, sz);
407                         kunmap_atomic(buffer);
408                         local_irq_restore(flags);
409 
410                         size -= sz;
411                         pfn++;
412                         vaddr += sz;
413                         offset = 0;
414                 }
415         } else if (dir == DMA_TO_DEVICE) {
416                 memcpy(vaddr, phys_to_virt(orig_addr), size);
417         } else {
418                 memcpy(phys_to_virt(orig_addr), vaddr, size);
419         }
420 }
421 
422 phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
423                                    dma_addr_t tbl_dma_addr,
424                                    phys_addr_t orig_addr, size_t size,
425                                    enum dma_data_direction dir)
426 {
427         unsigned long flags;
428         phys_addr_t tlb_addr;
429         unsigned int nslots, stride, index, wrap;
430         int i;
431         unsigned long mask;
432         unsigned long offset_slots;
433         unsigned long max_slots;
434 
435         if (no_iotlb_memory)
436                 panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
437 
438         mask = dma_get_seg_boundary(hwdev);
439 
440         tbl_dma_addr &= mask;
441 
442         offset_slots = ALIGN(tbl_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
443 
444         /*
445          * Carefully handle integer overflow which can occur when mask == ~0UL.
446          */
447         max_slots = mask + 1
448                     ? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT
449                     : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
450 
451         /*
452          * For mappings greater than a page, we limit the stride (and
453          * hence alignment) to a page size.
454          */
455         nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
456         if (size > PAGE_SIZE)
457                 stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
458         else
459                 stride = 1;
460 
461         BUG_ON(!nslots);
462 
463         /*
464          * Find suitable number of IO TLB entries size that will fit this
465          * request and allocate a buffer from that IO TLB pool.
466          */
467         spin_lock_irqsave(&io_tlb_lock, flags);
468         index = ALIGN(io_tlb_index, stride);
469         if (index >= io_tlb_nslabs)
470                 index = 0;
471         wrap = index;
472 
473         do {
474                 while (iommu_is_span_boundary(index, nslots, offset_slots,
475                                               max_slots)) {
476                         index += stride;
477                         if (index >= io_tlb_nslabs)
478                                 index = 0;
479                         if (index == wrap)
480                                 goto not_found;
481                 }
482 
483                 /*
484                  * If we find a slot that indicates we have 'nslots' number of
485                  * contiguous buffers, we allocate the buffers from that slot
486                  * and mark the entries as '' indicating unavailable.
487                  */
488                 if (io_tlb_list[index] >= nslots) {
489                         int count = 0;
490 
491                         for (i = index; i < (int) (index + nslots); i++)
492                                 io_tlb_list[i] = 0;
493                         for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) && io_tlb_list[i]; i--)
494                                 io_tlb_list[i] = ++count;
495                         tlb_addr = io_tlb_start + (index << IO_TLB_SHIFT);
496 
497                         /*
498                          * Update the indices to avoid searching in the next
499                          * round.
500                          */
501                         io_tlb_index = ((index + nslots) < io_tlb_nslabs
502                                         ? (index + nslots) : 0);
503 
504                         goto found;
505                 }
506                 index += stride;
507                 if (index >= io_tlb_nslabs)
508                         index = 0;
509         } while (index != wrap);
510 
511 not_found:
512         spin_unlock_irqrestore(&io_tlb_lock, flags);
513         if (printk_ratelimit())
514                 dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n", size);
515         return SWIOTLB_MAP_ERROR;
516 found:
517         spin_unlock_irqrestore(&io_tlb_lock, flags);
518 
519         /*
520          * Save away the mapping from the original address to the DMA address.
521          * This is needed when we sync the memory.  Then we sync the buffer if
522          * needed.
523          */
524         for (i = 0; i < nslots; i++)
525                 io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
526         if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
527                 swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE);
528 
529         return tlb_addr;
530 }
531 EXPORT_SYMBOL_GPL(swiotlb_tbl_map_single);
532 
533 /*
534  * Allocates bounce buffer and returns its kernel virtual address.
535  */
536 
537 phys_addr_t map_single(struct device *hwdev, phys_addr_t phys, size_t size,
538                        enum dma_data_direction dir)
539 {
540         dma_addr_t start_dma_addr = phys_to_dma(hwdev, io_tlb_start);
541 
542         return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, dir);
543 }
544 
545 /*
546  * dma_addr is the kernel virtual address of the bounce buffer to unmap.
547  */
548 void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
549                               size_t size, enum dma_data_direction dir)
550 {
551         unsigned long flags;
552         int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
553         int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
554         phys_addr_t orig_addr = io_tlb_orig_addr[index];
555 
556         /*
557          * First, sync the memory before unmapping the entry
558          */
559         if (orig_addr && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
560                 swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
561 
562         /*
563          * Return the buffer to the free list by setting the corresponding
564          * entries to indicate the number of contiguous entries available.
565          * While returning the entries to the free list, we merge the entries
566          * with slots below and above the pool being returned.
567          */
568         spin_lock_irqsave(&io_tlb_lock, flags);
569         {
570                 count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
571                          io_tlb_list[index + nslots] : 0);
572                 /*
573                  * Step 1: return the slots to the free list, merging the
574                  * slots with superceeding slots
575                  */
576                 for (i = index + nslots - 1; i >= index; i--)
577                         io_tlb_list[i] = ++count;
578                 /*
579                  * Step 2: merge the returned slots with the preceding slots,
580                  * if available (non zero)
581                  */
582                 for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--)
583                         io_tlb_list[i] = ++count;
584         }
585         spin_unlock_irqrestore(&io_tlb_lock, flags);
586 }
587 EXPORT_SYMBOL_GPL(swiotlb_tbl_unmap_single);
588 
589 void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
590                              size_t size, enum dma_data_direction dir,
591                              enum dma_sync_target target)
592 {
593         int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
594         phys_addr_t orig_addr = io_tlb_orig_addr[index];
595 
596         orig_addr += (unsigned long)tlb_addr & ((1 << IO_TLB_SHIFT) - 1);
597 
598         switch (target) {
599         case SYNC_FOR_CPU:
600                 if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
601                         swiotlb_bounce(orig_addr, tlb_addr,
602                                        size, DMA_FROM_DEVICE);
603                 else
604                         BUG_ON(dir != DMA_TO_DEVICE);
605                 break;
606         case SYNC_FOR_DEVICE:
607                 if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
608                         swiotlb_bounce(orig_addr, tlb_addr,
609                                        size, DMA_TO_DEVICE);
610                 else
611                         BUG_ON(dir != DMA_FROM_DEVICE);
612                 break;
613         default:
614                 BUG();
615         }
616 }
617 EXPORT_SYMBOL_GPL(swiotlb_tbl_sync_single);
618 
619 void *
620 swiotlb_alloc_coherent(struct device *hwdev, size_t size,
621                        dma_addr_t *dma_handle, gfp_t flags)
622 {
623         dma_addr_t dev_addr;
624         void *ret;
625         int order = get_order(size);
626         u64 dma_mask = DMA_BIT_MASK(32);
627 
628         if (hwdev && hwdev->coherent_dma_mask)
629                 dma_mask = hwdev->coherent_dma_mask;
630 
631         ret = (void *)__get_free_pages(flags, order);
632         if (ret) {
633                 dev_addr = swiotlb_virt_to_bus(hwdev, ret);
634                 if (dev_addr + size - 1 > dma_mask) {
635                         /*
636                          * The allocated memory isn't reachable by the device.
637                          */
638                         free_pages((unsigned long) ret, order);
639                         ret = NULL;
640                 }
641         }
642         if (!ret) {
643                 /*
644                  * We are either out of memory or the device can't DMA to
645                  * GFP_DMA memory; fall back on map_single(), which
646                  * will grab memory from the lowest available address range.
647                  */
648                 phys_addr_t paddr = map_single(hwdev, 0, size, DMA_FROM_DEVICE);
649                 if (paddr == SWIOTLB_MAP_ERROR)
650                         return NULL;
651 
652                 ret = phys_to_virt(paddr);
653                 dev_addr = phys_to_dma(hwdev, paddr);
654 
655                 /* Confirm address can be DMA'd by device */
656                 if (dev_addr + size - 1 > dma_mask) {
657                         printk("hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n",
658                                (unsigned long long)dma_mask,
659                                (unsigned long long)dev_addr);
660 
661                         /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
662                         swiotlb_tbl_unmap_single(hwdev, paddr,
663                                                  size, DMA_TO_DEVICE);
664                         return NULL;
665                 }
666         }
667 
668         *dma_handle = dev_addr;
669         memset(ret, 0, size);
670 
671         return ret;
672 }
673 EXPORT_SYMBOL(swiotlb_alloc_coherent);
674 
675 void
676 swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
677                       dma_addr_t dev_addr)
678 {
679         phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
680 
681         WARN_ON(irqs_disabled());
682         if (!is_swiotlb_buffer(paddr))
683                 free_pages((unsigned long)vaddr, get_order(size));
684         else
685                 /* DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single */
686                 swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE);
687 }
688 EXPORT_SYMBOL(swiotlb_free_coherent);
689 
690 static void
691 swiotlb_full(struct device *dev, size_t size, enum dma_data_direction dir,
692              int do_panic)
693 {
694         /*
695          * Ran out of IOMMU space for this operation. This is very bad.
696          * Unfortunately the drivers cannot handle this operation properly.
697          * unless they check for dma_mapping_error (most don't)
698          * When the mapping is small enough return a static buffer to limit
699          * the damage, or panic when the transfer is too big.
700          */
701         printk(KERN_ERR "DMA: Out of SW-IOMMU space for %zu bytes at "
702                "device %s\n", size, dev ? dev_name(dev) : "?");
703 
704         if (size <= io_tlb_overflow || !do_panic)
705                 return;
706 
707         if (dir == DMA_BIDIRECTIONAL)
708                 panic("DMA: Random memory could be DMA accessed\n");
709         if (dir == DMA_FROM_DEVICE)
710                 panic("DMA: Random memory could be DMA written\n");
711         if (dir == DMA_TO_DEVICE)
712                 panic("DMA: Random memory could be DMA read\n");
713 }
714 
715 /*
716  * Map a single buffer of the indicated size for DMA in streaming mode.  The
717  * physical address to use is returned.
718  *
719  * Once the device is given the dma address, the device owns this memory until
720  * either swiotlb_unmap_page or swiotlb_dma_sync_single is performed.
721  */
722 dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
723                             unsigned long offset, size_t size,
724                             enum dma_data_direction dir,
725                             struct dma_attrs *attrs)
726 {
727         phys_addr_t map, phys = page_to_phys(page) + offset;
728         dma_addr_t dev_addr = phys_to_dma(dev, phys);
729 
730         BUG_ON(dir == DMA_NONE);
731         /*
732          * If the address happens to be in the device's DMA window,
733          * we can safely return the device addr and not worry about bounce
734          * buffering it.
735          */
736         if (dma_capable(dev, dev_addr, size) && !swiotlb_force)
737                 return dev_addr;
738 
739         trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
740 
741         /* Oh well, have to allocate and map a bounce buffer. */
742         map = map_single(dev, phys, size, dir);
743         if (map == SWIOTLB_MAP_ERROR) {
744                 swiotlb_full(dev, size, dir, 1);
745                 return phys_to_dma(dev, io_tlb_overflow_buffer);
746         }
747 
748         dev_addr = phys_to_dma(dev, map);
749 
750         /* Ensure that the address returned is DMA'ble */
751         if (!dma_capable(dev, dev_addr, size)) {
752                 swiotlb_tbl_unmap_single(dev, map, size, dir);
753                 return phys_to_dma(dev, io_tlb_overflow_buffer);
754         }
755 
756         return dev_addr;
757 }
758 EXPORT_SYMBOL_GPL(swiotlb_map_page);
759 
760 /*
761  * Unmap a single streaming mode DMA translation.  The dma_addr and size must
762  * match what was provided for in a previous swiotlb_map_page call.  All
763  * other usages are undefined.
764  *
765  * After this call, reads by the cpu to the buffer are guaranteed to see
766  * whatever the device wrote there.
767  */
768 static void unmap_single(struct device *hwdev, dma_addr_t dev_addr,
769                          size_t size, enum dma_data_direction dir)
770 {
771         phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
772 
773         BUG_ON(dir == DMA_NONE);
774 
775         if (is_swiotlb_buffer(paddr)) {
776                 swiotlb_tbl_unmap_single(hwdev, paddr, size, dir);
777                 return;
778         }
779 
780         if (dir != DMA_FROM_DEVICE)
781                 return;
782 
783         /*
784          * phys_to_virt doesn't work with hihgmem page but we could
785          * call dma_mark_clean() with hihgmem page here. However, we
786          * are fine since dma_mark_clean() is null on POWERPC. We can
787          * make dma_mark_clean() take a physical address if necessary.
788          */
789         dma_mark_clean(phys_to_virt(paddr), size);
790 }
791 
792 void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
793                         size_t size, enum dma_data_direction dir,
794                         struct dma_attrs *attrs)
795 {
796         unmap_single(hwdev, dev_addr, size, dir);
797 }
798 EXPORT_SYMBOL_GPL(swiotlb_unmap_page);
799 
800 /*
801  * Make physical memory consistent for a single streaming mode DMA translation
802  * after a transfer.
803  *
804  * If you perform a swiotlb_map_page() but wish to interrogate the buffer
805  * using the cpu, yet do not wish to teardown the dma mapping, you must
806  * call this function before doing so.  At the next point you give the dma
807  * address back to the card, you must first perform a
808  * swiotlb_dma_sync_for_device, and then the device again owns the buffer
809  */
810 static void
811 swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
812                     size_t size, enum dma_data_direction dir,
813                     enum dma_sync_target target)
814 {
815         phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
816 
817         BUG_ON(dir == DMA_NONE);
818 
819         if (is_swiotlb_buffer(paddr)) {
820                 swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target);
821                 return;
822         }
823 
824         if (dir != DMA_FROM_DEVICE)
825                 return;
826 
827         dma_mark_clean(phys_to_virt(paddr), size);
828 }
829 
830 void
831 swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
832                             size_t size, enum dma_data_direction dir)
833 {
834         swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
835 }
836 EXPORT_SYMBOL(swiotlb_sync_single_for_cpu);
837 
838 void
839 swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
840                                size_t size, enum dma_data_direction dir)
841 {
842         swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
843 }
844 EXPORT_SYMBOL(swiotlb_sync_single_for_device);
845 
846 /*
847  * Map a set of buffers described by scatterlist in streaming mode for DMA.
848  * This is the scatter-gather version of the above swiotlb_map_page
849  * interface.  Here the scatter gather list elements are each tagged with the
850  * appropriate dma address and length.  They are obtained via
851  * sg_dma_{address,length}(SG).
852  *
853  * NOTE: An implementation may be able to use a smaller number of
854  *       DMA address/length pairs than there are SG table elements.
855  *       (for example via virtual mapping capabilities)
856  *       The routine returns the number of addr/length pairs actually
857  *       used, at most nents.
858  *
859  * Device ownership issues as mentioned above for swiotlb_map_page are the
860  * same here.
861  */
862 int
863 swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
864                      enum dma_data_direction dir, struct dma_attrs *attrs)
865 {
866         struct scatterlist *sg;
867         int i;
868 
869         BUG_ON(dir == DMA_NONE);
870 
871         for_each_sg(sgl, sg, nelems, i) {
872                 phys_addr_t paddr = sg_phys(sg);
873                 dma_addr_t dev_addr = phys_to_dma(hwdev, paddr);
874 
875                 if (swiotlb_force ||
876                     !dma_capable(hwdev, dev_addr, sg->length)) {
877                         phys_addr_t map = map_single(hwdev, sg_phys(sg),
878                                                      sg->length, dir);
879                         if (map == SWIOTLB_MAP_ERROR) {
880                                 /* Don't panic here, we expect map_sg users
881                                    to do proper error handling. */
882                                 swiotlb_full(hwdev, sg->length, dir, 0);
883                                 swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
884                                                        attrs);
885                                 sg_dma_len(sgl) = 0;
886                                 return 0;
887                         }
888                         sg->dma_address = phys_to_dma(hwdev, map);
889                 } else
890                         sg->dma_address = dev_addr;
891                 sg_dma_len(sg) = sg->length;
892         }
893         return nelems;
894 }
895 EXPORT_SYMBOL(swiotlb_map_sg_attrs);
896 
897 int
898 swiotlb_map_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
899                enum dma_data_direction dir)
900 {
901         return swiotlb_map_sg_attrs(hwdev, sgl, nelems, dir, NULL);
902 }
903 EXPORT_SYMBOL(swiotlb_map_sg);
904 
905 /*
906  * Unmap a set of streaming mode DMA translations.  Again, cpu read rules
907  * concerning calls here are the same as for swiotlb_unmap_page() above.
908  */
909 void
910 swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
911                        int nelems, enum dma_data_direction dir, struct dma_attrs *attrs)
912 {
913         struct scatterlist *sg;
914         int i;
915 
916         BUG_ON(dir == DMA_NONE);
917 
918         for_each_sg(sgl, sg, nelems, i)
919                 unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir);
920 
921 }
922 EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);
923 
924 void
925 swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
926                  enum dma_data_direction dir)
927 {
928         return swiotlb_unmap_sg_attrs(hwdev, sgl, nelems, dir, NULL);
929 }
930 EXPORT_SYMBOL(swiotlb_unmap_sg);
931 
932 /*
933  * Make physical memory consistent for a set of streaming mode DMA translations
934  * after a transfer.
935  *
936  * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
937  * and usage.
938  */
939 static void
940 swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
941                 int nelems, enum dma_data_direction dir,
942                 enum dma_sync_target target)
943 {
944         struct scatterlist *sg;
945         int i;
946 
947         for_each_sg(sgl, sg, nelems, i)
948                 swiotlb_sync_single(hwdev, sg->dma_address,
949                                     sg_dma_len(sg), dir, target);
950 }
951 
952 void
953 swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
954                         int nelems, enum dma_data_direction dir)
955 {
956         swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
957 }
958 EXPORT_SYMBOL(swiotlb_sync_sg_for_cpu);
959 
960 void
961 swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
962                            int nelems, enum dma_data_direction dir)
963 {
964         swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
965 }
966 EXPORT_SYMBOL(swiotlb_sync_sg_for_device);
967 
968 int
969 swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
970 {
971         return (dma_addr == phys_to_dma(hwdev, io_tlb_overflow_buffer));
972 }
973 EXPORT_SYMBOL(swiotlb_dma_mapping_error);
974 
975 /*
976  * Return whether the given device DMA address mask can be supported
977  * properly.  For example, if your device can only drive the low 24-bits
978  * during bus mastering, then you would pass 0x00ffffff as the mask to
979  * this function.
980  */
981 int
982 swiotlb_dma_supported(struct device *hwdev, u64 mask)
983 {
984         return phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
985 }
986 EXPORT_SYMBOL(swiotlb_dma_supported);
987 

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