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>
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
20 #define pr_fmt(fmt) "software IO TLB: " fmt
22 #include <linux/cache.h>
23 #include <linux/dma-direct.h>
25 #include <linux/export.h>
26 #include <linux/spinlock.h>
27 #include <linux/string.h>
28 #include <linux/swiotlb.h>
29 #include <linux/pfn.h>
30 #include <linux/types.h>
31 #include <linux/ctype.h>
32 #include <linux/highmem.h>
33 #include <linux/gfp.h>
34 #include <linux/scatterlist.h>
35 #include <linux/mem_encrypt.h>
36 #include <linux/set_memory.h>
37 #ifdef CONFIG_DEBUG_FS
38 #include <linux/debugfs.h>
44 #include <linux/init.h>
45 #include <linux/memblock.h>
46 #include <linux/iommu-helper.h>
48 #define CREATE_TRACE_POINTS
49 #include <trace/events/swiotlb.h>
51 #define OFFSET(val,align) ((unsigned long) \
52 ( (val) & ( (align) - 1)))
54 #define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
57 * Minimum IO TLB size to bother booting with. Systems with mainly
58 * 64bit capable cards will only lightly use the swiotlb. If we can't
59 * allocate a contiguous 1MB, we're probably in trouble anyway.
61 #define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
63 enum swiotlb_force swiotlb_force;
66 * Used to do a quick range check in swiotlb_tbl_unmap_single and
67 * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
70 phys_addr_t io_tlb_start, io_tlb_end;
73 * The number of IO TLB blocks (in groups of 64) between io_tlb_start and
74 * io_tlb_end. This is command line adjustable via setup_io_tlb_npages.
76 static unsigned long io_tlb_nslabs;
79 * The number of used IO TLB block
81 static unsigned long io_tlb_used;
84 * This is a free list describing the number of free entries available from
87 static unsigned int *io_tlb_list;
88 static unsigned int io_tlb_index;
91 * Max segment that we can provide which (if pages are contingous) will
92 * not be bounced (unless SWIOTLB_FORCE is set).
94 unsigned int max_segment;
97 * We need to save away the original address corresponding to a mapped entry
98 * for the sync operations.
100 #define INVALID_PHYS_ADDR (~(phys_addr_t)0)
101 static phys_addr_t *io_tlb_orig_addr;
104 * Protect the above data structures in the map and unmap calls
106 static DEFINE_SPINLOCK(io_tlb_lock);
108 static int late_alloc;
111 setup_io_tlb_npages(char *str)
114 io_tlb_nslabs = simple_strtoul(str, &str, 0);
115 /* avoid tail segment of size < IO_TLB_SEGSIZE */
116 io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
120 if (!strcmp(str, "force")) {
121 swiotlb_force = SWIOTLB_FORCE;
122 } else if (!strcmp(str, "noforce")) {
123 swiotlb_force = SWIOTLB_NO_FORCE;
129 early_param("swiotlb", setup_io_tlb_npages);
131 unsigned long swiotlb_nr_tbl(void)
133 return io_tlb_nslabs;
135 EXPORT_SYMBOL_GPL(swiotlb_nr_tbl);
137 unsigned int swiotlb_max_segment(void)
141 EXPORT_SYMBOL_GPL(swiotlb_max_segment);
143 void swiotlb_set_max_segment(unsigned int val)
145 if (swiotlb_force == SWIOTLB_FORCE)
148 max_segment = rounddown(val, PAGE_SIZE);
151 /* default to 64MB */
152 #define IO_TLB_DEFAULT_SIZE (64UL<<20)
153 unsigned long swiotlb_size_or_default(void)
157 size = io_tlb_nslabs << IO_TLB_SHIFT;
159 return size ? size : (IO_TLB_DEFAULT_SIZE);
162 static bool no_iotlb_memory;
164 void swiotlb_print_info(void)
166 unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;
168 if (no_iotlb_memory) {
169 pr_warn("No low mem\n");
173 pr_info("mapped [mem %#010llx-%#010llx] (%luMB)\n",
174 (unsigned long long)io_tlb_start,
175 (unsigned long long)io_tlb_end,
180 * Early SWIOTLB allocation may be too early to allow an architecture to
181 * perform the desired operations. This function allows the architecture to
182 * call SWIOTLB when the operations are possible. It needs to be called
183 * before the SWIOTLB memory is used.
185 void __init swiotlb_update_mem_attributes(void)
190 if (no_iotlb_memory || late_alloc)
193 vaddr = phys_to_virt(io_tlb_start);
194 bytes = PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT);
195 set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
196 memset(vaddr, 0, bytes);
199 int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
201 unsigned long i, bytes;
204 bytes = nslabs << IO_TLB_SHIFT;
206 io_tlb_nslabs = nslabs;
207 io_tlb_start = __pa(tlb);
208 io_tlb_end = io_tlb_start + bytes;
211 * Allocate and initialize the free list array. This array is used
212 * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
213 * between io_tlb_start and io_tlb_end.
215 alloc_size = PAGE_ALIGN(io_tlb_nslabs * sizeof(int));
216 io_tlb_list = memblock_alloc(alloc_size, PAGE_SIZE);
218 panic("%s: Failed to allocate %zu bytes align=0x%lx\n",
219 __func__, alloc_size, PAGE_SIZE);
221 alloc_size = PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t));
222 io_tlb_orig_addr = memblock_alloc(alloc_size, PAGE_SIZE);
223 if (!io_tlb_orig_addr)
224 panic("%s: Failed to allocate %zu bytes align=0x%lx\n",
225 __func__, alloc_size, PAGE_SIZE);
227 for (i = 0; i < io_tlb_nslabs; i++) {
228 io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
229 io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
234 swiotlb_print_info();
236 swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT);
241 * Statically reserve bounce buffer space and initialize bounce buffer data
242 * structures for the software IO TLB used to implement the DMA API.
245 swiotlb_init(int verbose)
247 size_t default_size = IO_TLB_DEFAULT_SIZE;
248 unsigned char *vstart;
251 if (!io_tlb_nslabs) {
252 io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
253 io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
256 bytes = io_tlb_nslabs << IO_TLB_SHIFT;
258 /* Get IO TLB memory from the low pages */
259 vstart = memblock_alloc_low(PAGE_ALIGN(bytes), PAGE_SIZE);
260 if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose))
264 memblock_free_early(io_tlb_start,
265 PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
266 pr_warn("Cannot allocate buffer");
267 no_iotlb_memory = true;
271 * Systems with larger DMA zones (those that don't support ISA) can
272 * initialize the swiotlb later using the slab allocator if needed.
273 * This should be just like above, but with some error catching.
276 swiotlb_late_init_with_default_size(size_t default_size)
278 unsigned long bytes, req_nslabs = io_tlb_nslabs;
279 unsigned char *vstart = NULL;
283 if (!io_tlb_nslabs) {
284 io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
285 io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
289 * Get IO TLB memory from the low pages
291 order = get_order(io_tlb_nslabs << IO_TLB_SHIFT);
292 io_tlb_nslabs = SLABS_PER_PAGE << order;
293 bytes = io_tlb_nslabs << IO_TLB_SHIFT;
295 while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
296 vstart = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
304 io_tlb_nslabs = req_nslabs;
307 if (order != get_order(bytes)) {
308 pr_warn("only able to allocate %ld MB\n",
309 (PAGE_SIZE << order) >> 20);
310 io_tlb_nslabs = SLABS_PER_PAGE << order;
312 rc = swiotlb_late_init_with_tbl(vstart, io_tlb_nslabs);
314 free_pages((unsigned long)vstart, order);
320 swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
322 unsigned long i, bytes;
324 bytes = nslabs << IO_TLB_SHIFT;
326 io_tlb_nslabs = nslabs;
327 io_tlb_start = virt_to_phys(tlb);
328 io_tlb_end = io_tlb_start + bytes;
330 set_memory_decrypted((unsigned long)tlb, bytes >> PAGE_SHIFT);
331 memset(tlb, 0, bytes);
334 * Allocate and initialize the free list array. This array is used
335 * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
336 * between io_tlb_start and io_tlb_end.
338 io_tlb_list = (unsigned int *)__get_free_pages(GFP_KERNEL,
339 get_order(io_tlb_nslabs * sizeof(int)));
343 io_tlb_orig_addr = (phys_addr_t *)
344 __get_free_pages(GFP_KERNEL,
345 get_order(io_tlb_nslabs *
346 sizeof(phys_addr_t)));
347 if (!io_tlb_orig_addr)
350 for (i = 0; i < io_tlb_nslabs; i++) {
351 io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
352 io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
356 swiotlb_print_info();
360 swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT);
365 free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
376 void __init swiotlb_exit(void)
378 if (!io_tlb_orig_addr)
382 free_pages((unsigned long)io_tlb_orig_addr,
383 get_order(io_tlb_nslabs * sizeof(phys_addr_t)));
384 free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
386 free_pages((unsigned long)phys_to_virt(io_tlb_start),
387 get_order(io_tlb_nslabs << IO_TLB_SHIFT));
389 memblock_free_late(__pa(io_tlb_orig_addr),
390 PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
391 memblock_free_late(__pa(io_tlb_list),
392 PAGE_ALIGN(io_tlb_nslabs * sizeof(int)));
393 memblock_free_late(io_tlb_start,
394 PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
403 * Bounce: copy the swiotlb buffer from or back to the original dma location
405 static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
406 size_t size, enum dma_data_direction dir)
408 unsigned long pfn = PFN_DOWN(orig_addr);
409 unsigned char *vaddr = phys_to_virt(tlb_addr);
411 if (PageHighMem(pfn_to_page(pfn))) {
412 /* The buffer does not have a mapping. Map it in and copy */
413 unsigned int offset = orig_addr & ~PAGE_MASK;
419 sz = min_t(size_t, PAGE_SIZE - offset, size);
421 local_irq_save(flags);
422 buffer = kmap_atomic(pfn_to_page(pfn));
423 if (dir == DMA_TO_DEVICE)
424 memcpy(vaddr, buffer + offset, sz);
426 memcpy(buffer + offset, vaddr, sz);
427 kunmap_atomic(buffer);
428 local_irq_restore(flags);
435 } else if (dir == DMA_TO_DEVICE) {
436 memcpy(vaddr, phys_to_virt(orig_addr), size);
438 memcpy(phys_to_virt(orig_addr), vaddr, size);
442 phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
443 dma_addr_t tbl_dma_addr,
444 phys_addr_t orig_addr, size_t size,
445 enum dma_data_direction dir,
449 phys_addr_t tlb_addr;
450 unsigned int nslots, stride, index, wrap;
453 unsigned long offset_slots;
454 unsigned long max_slots;
457 panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
459 if (mem_encrypt_active())
460 pr_warn_once("%s is active and system is using DMA bounce buffers\n",
461 sme_active() ? "SME" : "SEV");
463 mask = dma_get_seg_boundary(hwdev);
465 tbl_dma_addr &= mask;
467 offset_slots = ALIGN(tbl_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
470 * Carefully handle integer overflow which can occur when mask == ~0UL.
473 ? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT
474 : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
477 * For mappings greater than or equal to a page, we limit the stride
478 * (and hence alignment) to a page size.
480 nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
481 if (size >= PAGE_SIZE)
482 stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
489 * Find suitable number of IO TLB entries size that will fit this
490 * request and allocate a buffer from that IO TLB pool.
492 spin_lock_irqsave(&io_tlb_lock, flags);
494 if (unlikely(nslots > io_tlb_nslabs - io_tlb_used))
497 index = ALIGN(io_tlb_index, stride);
498 if (index >= io_tlb_nslabs)
503 while (iommu_is_span_boundary(index, nslots, offset_slots,
506 if (index >= io_tlb_nslabs)
513 * If we find a slot that indicates we have 'nslots' number of
514 * contiguous buffers, we allocate the buffers from that slot
515 * and mark the entries as '0' indicating unavailable.
517 if (io_tlb_list[index] >= nslots) {
520 for (i = index; i < (int) (index + nslots); i++)
522 for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) && io_tlb_list[i]; i--)
523 io_tlb_list[i] = ++count;
524 tlb_addr = io_tlb_start + (index << IO_TLB_SHIFT);
527 * Update the indices to avoid searching in the next
530 io_tlb_index = ((index + nslots) < io_tlb_nslabs
531 ? (index + nslots) : 0);
536 if (index >= io_tlb_nslabs)
538 } while (index != wrap);
541 spin_unlock_irqrestore(&io_tlb_lock, flags);
542 if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
543 dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n", size);
544 return DMA_MAPPING_ERROR;
546 io_tlb_used += nslots;
547 spin_unlock_irqrestore(&io_tlb_lock, flags);
550 * Save away the mapping from the original address to the DMA address.
551 * This is needed when we sync the memory. Then we sync the buffer if
554 for (i = 0; i < nslots; i++)
555 io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
556 if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
557 (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
558 swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE);
564 * tlb_addr is the physical address of the bounce buffer to unmap.
566 void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
567 size_t size, enum dma_data_direction dir,
571 int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
572 int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
573 phys_addr_t orig_addr = io_tlb_orig_addr[index];
576 * First, sync the memory before unmapping the entry
578 if (orig_addr != INVALID_PHYS_ADDR &&
579 !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
580 ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
581 swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
584 * Return the buffer to the free list by setting the corresponding
585 * entries to indicate the number of contiguous entries available.
586 * While returning the entries to the free list, we merge the entries
587 * with slots below and above the pool being returned.
589 spin_lock_irqsave(&io_tlb_lock, flags);
591 count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
592 io_tlb_list[index + nslots] : 0);
594 * Step 1: return the slots to the free list, merging the
595 * slots with superceeding slots
597 for (i = index + nslots - 1; i >= index; i--) {
598 io_tlb_list[i] = ++count;
599 io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
602 * Step 2: merge the returned slots with the preceding slots,
603 * if available (non zero)
605 for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--)
606 io_tlb_list[i] = ++count;
608 io_tlb_used -= nslots;
610 spin_unlock_irqrestore(&io_tlb_lock, flags);
613 void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
614 size_t size, enum dma_data_direction dir,
615 enum dma_sync_target target)
617 int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
618 phys_addr_t orig_addr = io_tlb_orig_addr[index];
620 if (orig_addr == INVALID_PHYS_ADDR)
622 orig_addr += (unsigned long)tlb_addr & ((1 << IO_TLB_SHIFT) - 1);
626 if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
627 swiotlb_bounce(orig_addr, tlb_addr,
628 size, DMA_FROM_DEVICE);
630 BUG_ON(dir != DMA_TO_DEVICE);
632 case SYNC_FOR_DEVICE:
633 if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
634 swiotlb_bounce(orig_addr, tlb_addr,
635 size, DMA_TO_DEVICE);
637 BUG_ON(dir != DMA_FROM_DEVICE);
645 * Create a swiotlb mapping for the buffer at @phys, and in case of DMAing
646 * to the device copy the data into it as well.
648 bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr,
649 size_t size, enum dma_data_direction dir, unsigned long attrs)
651 trace_swiotlb_bounced(dev, *dma_addr, size, swiotlb_force);
653 if (unlikely(swiotlb_force == SWIOTLB_NO_FORCE)) {
654 dev_warn_ratelimited(dev,
655 "Cannot do DMA to address %pa\n", phys);
659 /* Oh well, have to allocate and map a bounce buffer. */
660 *phys = swiotlb_tbl_map_single(dev, __phys_to_dma(dev, io_tlb_start),
661 *phys, size, dir, attrs);
662 if (*phys == DMA_MAPPING_ERROR)
665 /* Ensure that the address returned is DMA'ble */
666 *dma_addr = __phys_to_dma(dev, *phys);
667 if (unlikely(!dma_capable(dev, *dma_addr, size))) {
668 swiotlb_tbl_unmap_single(dev, *phys, size, dir,
669 attrs | DMA_ATTR_SKIP_CPU_SYNC);
676 size_t swiotlb_max_mapping_size(struct device *dev)
678 return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
681 bool is_swiotlb_active(void)
684 * When SWIOTLB is initialized, even if io_tlb_start points to physical
685 * address zero, io_tlb_end surely doesn't.
687 return io_tlb_end != 0;
690 #ifdef CONFIG_DEBUG_FS
692 static int __init swiotlb_create_debugfs(void)
694 struct dentry *d_swiotlb_usage;
697 d_swiotlb_usage = debugfs_create_dir("swiotlb", NULL);
699 if (!d_swiotlb_usage)
702 ent = debugfs_create_ulong("io_tlb_nslabs", 0400,
703 d_swiotlb_usage, &io_tlb_nslabs);
707 ent = debugfs_create_ulong("io_tlb_used", 0400,
708 d_swiotlb_usage, &io_tlb_used);
715 debugfs_remove_recursive(d_swiotlb_usage);
719 late_initcall(swiotlb_create_debugfs);