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CommitLineData
b097186f
KRW
1/*
2 * Copyright 2010
3 * by Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
4 *
5 * This code provides a IOMMU for Xen PV guests with PCI passthrough.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License v2.0 as published by
9 * the Free Software Foundation
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * PV guests under Xen are running in an non-contiguous memory architecture.
17 *
18 * When PCI pass-through is utilized, this necessitates an IOMMU for
19 * translating bus (DMA) to virtual and vice-versa and also providing a
20 * mechanism to have contiguous pages for device drivers operations (say DMA
21 * operations).
22 *
23 * Specifically, under Xen the Linux idea of pages is an illusion. It
24 * assumes that pages start at zero and go up to the available memory. To
25 * help with that, the Linux Xen MMU provides a lookup mechanism to
26 * translate the page frame numbers (PFN) to machine frame numbers (MFN)
27 * and vice-versa. The MFN are the "real" frame numbers. Furthermore
28 * memory is not contiguous. Xen hypervisor stitches memory for guests
29 * from different pools, which means there is no guarantee that PFN==MFN
30 * and PFN+1==MFN+1. Lastly with Xen 4.0, pages (in debug mode) are
31 * allocated in descending order (high to low), meaning the guest might
32 * never get any MFN's under the 4GB mark.
33 *
34 */
35
283c0972
JP
36#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
37
b097186f
KRW
38#include <linux/bootmem.h>
39#include <linux/dma-mapping.h>
63c9744b 40#include <linux/export.h>
b097186f
KRW
41#include <xen/swiotlb-xen.h>
42#include <xen/page.h>
43#include <xen/xen-ops.h>
f4b2f07b 44#include <xen/hvc-console.h>
2b2b614d 45
83862ccf 46#include <asm/dma-mapping.h>
1b65c4e5 47#include <asm/xen/page-coherent.h>
e1d8f62a 48
2b2b614d 49#include <trace/events/swiotlb.h>
b097186f
KRW
50/*
51 * Used to do a quick range check in swiotlb_tbl_unmap_single and
52 * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
53 * API.
54 */
55
83862ccf
SS
56#ifndef CONFIG_X86
57static unsigned long dma_alloc_coherent_mask(struct device *dev,
58 gfp_t gfp)
59{
60 unsigned long dma_mask = 0;
61
62 dma_mask = dev->coherent_dma_mask;
63 if (!dma_mask)
64 dma_mask = (gfp & GFP_DMA) ? DMA_BIT_MASK(24) : DMA_BIT_MASK(32);
65
66 return dma_mask;
67}
68#endif
69
4d048dbc
CH
70#define XEN_SWIOTLB_ERROR_CODE (~(dma_addr_t)0x0)
71
b097186f
KRW
72static char *xen_io_tlb_start, *xen_io_tlb_end;
73static unsigned long xen_io_tlb_nslabs;
74/*
75 * Quick lookup value of the bus address of the IOTLB.
76 */
77
b8b0f559 78static u64 start_dma_addr;
b097186f 79
e17b2f11 80/*
9435cce8 81 * Both of these functions should avoid XEN_PFN_PHYS because phys_addr_t
e17b2f11
IC
82 * can be 32bit when dma_addr_t is 64bit leading to a loss in
83 * information if the shift is done before casting to 64bit.
84 */
6b42a7ea 85static inline dma_addr_t xen_phys_to_bus(phys_addr_t paddr)
b097186f 86{
9435cce8
JG
87 unsigned long bfn = pfn_to_bfn(XEN_PFN_DOWN(paddr));
88 dma_addr_t dma = (dma_addr_t)bfn << XEN_PAGE_SHIFT;
e17b2f11 89
9435cce8 90 dma |= paddr & ~XEN_PAGE_MASK;
e17b2f11
IC
91
92 return dma;
b097186f
KRW
93}
94
6b42a7ea 95static inline phys_addr_t xen_bus_to_phys(dma_addr_t baddr)
b097186f 96{
9435cce8
JG
97 unsigned long xen_pfn = bfn_to_pfn(XEN_PFN_DOWN(baddr));
98 dma_addr_t dma = (dma_addr_t)xen_pfn << XEN_PAGE_SHIFT;
e17b2f11
IC
99 phys_addr_t paddr = dma;
100
9435cce8 101 paddr |= baddr & ~XEN_PAGE_MASK;
e17b2f11
IC
102
103 return paddr;
b097186f
KRW
104}
105
6b42a7ea 106static inline dma_addr_t xen_virt_to_bus(void *address)
b097186f
KRW
107{
108 return xen_phys_to_bus(virt_to_phys(address));
109}
110
9435cce8 111static int check_pages_physically_contiguous(unsigned long xen_pfn,
b097186f
KRW
112 unsigned int offset,
113 size_t length)
114{
32e09870 115 unsigned long next_bfn;
b097186f
KRW
116 int i;
117 int nr_pages;
118
9435cce8
JG
119 next_bfn = pfn_to_bfn(xen_pfn);
120 nr_pages = (offset + length + XEN_PAGE_SIZE-1) >> XEN_PAGE_SHIFT;
b097186f
KRW
121
122 for (i = 1; i < nr_pages; i++) {
9435cce8 123 if (pfn_to_bfn(++xen_pfn) != ++next_bfn)
b097186f
KRW
124 return 0;
125 }
126 return 1;
127}
128
6b42a7ea 129static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
b097186f 130{
9435cce8
JG
131 unsigned long xen_pfn = XEN_PFN_DOWN(p);
132 unsigned int offset = p & ~XEN_PAGE_MASK;
b097186f 133
9435cce8 134 if (offset + size <= XEN_PAGE_SIZE)
b097186f 135 return 0;
9435cce8 136 if (check_pages_physically_contiguous(xen_pfn, offset, size))
b097186f
KRW
137 return 0;
138 return 1;
139}
140
141static int is_xen_swiotlb_buffer(dma_addr_t dma_addr)
142{
9435cce8
JG
143 unsigned long bfn = XEN_PFN_DOWN(dma_addr);
144 unsigned long xen_pfn = bfn_to_local_pfn(bfn);
145 phys_addr_t paddr = XEN_PFN_PHYS(xen_pfn);
b097186f
KRW
146
147 /* If the address is outside our domain, it CAN
148 * have the same virtual address as another address
149 * in our domain. Therefore _only_ check address within our domain.
150 */
9435cce8 151 if (pfn_valid(PFN_DOWN(paddr))) {
b097186f
KRW
152 return paddr >= virt_to_phys(xen_io_tlb_start) &&
153 paddr < virt_to_phys(xen_io_tlb_end);
154 }
155 return 0;
156}
157
158static int max_dma_bits = 32;
159
160static int
161xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
162{
163 int i, rc;
164 int dma_bits;
69908907 165 dma_addr_t dma_handle;
1b65c4e5 166 phys_addr_t p = virt_to_phys(buf);
b097186f
KRW
167
168 dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
169
170 i = 0;
171 do {
172 int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE);
173
174 do {
175 rc = xen_create_contiguous_region(
1b65c4e5 176 p + (i << IO_TLB_SHIFT),
b097186f 177 get_order(slabs << IO_TLB_SHIFT),
69908907 178 dma_bits, &dma_handle);
b097186f
KRW
179 } while (rc && dma_bits++ < max_dma_bits);
180 if (rc)
181 return rc;
182
183 i += slabs;
184 } while (i < nslabs);
185 return 0;
186}
1cef36a5
KRW
187static unsigned long xen_set_nslabs(unsigned long nr_tbl)
188{
189 if (!nr_tbl) {
190 xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
191 xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
192 } else
193 xen_io_tlb_nslabs = nr_tbl;
b097186f 194
1cef36a5
KRW
195 return xen_io_tlb_nslabs << IO_TLB_SHIFT;
196}
b097186f 197
5bab7864
KRW
198enum xen_swiotlb_err {
199 XEN_SWIOTLB_UNKNOWN = 0,
200 XEN_SWIOTLB_ENOMEM,
201 XEN_SWIOTLB_EFIXUP
202};
203
204static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
205{
206 switch (err) {
207 case XEN_SWIOTLB_ENOMEM:
208 return "Cannot allocate Xen-SWIOTLB buffer\n";
209 case XEN_SWIOTLB_EFIXUP:
210 return "Failed to get contiguous memory for DMA from Xen!\n"\
211 "You either: don't have the permissions, do not have"\
212 " enough free memory under 4GB, or the hypervisor memory"\
213 " is too fragmented!";
214 default:
215 break;
216 }
217 return "";
218}
b8277600 219int __ref xen_swiotlb_init(int verbose, bool early)
b097186f 220{
b8277600 221 unsigned long bytes, order;
f4b2f07b 222 int rc = -ENOMEM;
5bab7864 223 enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;
f4b2f07b 224 unsigned int repeat = 3;
5f98ecdb 225
1cef36a5 226 xen_io_tlb_nslabs = swiotlb_nr_tbl();
f4b2f07b 227retry:
1cef36a5 228 bytes = xen_set_nslabs(xen_io_tlb_nslabs);
b8277600 229 order = get_order(xen_io_tlb_nslabs << IO_TLB_SHIFT);
b097186f
KRW
230 /*
231 * Get IO TLB memory from any location.
232 */
b8277600
KRW
233 if (early)
234 xen_io_tlb_start = alloc_bootmem_pages(PAGE_ALIGN(bytes));
235 else {
236#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
237#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
238 while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
8746515d 239 xen_io_tlb_start = (void *)xen_get_swiotlb_free_pages(order);
b8277600
KRW
240 if (xen_io_tlb_start)
241 break;
242 order--;
243 }
244 if (order != get_order(bytes)) {
283c0972
JP
245 pr_warn("Warning: only able to allocate %ld MB for software IO TLB\n",
246 (PAGE_SIZE << order) >> 20);
b8277600
KRW
247 xen_io_tlb_nslabs = SLABS_PER_PAGE << order;
248 bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
249 }
250 }
f4b2f07b 251 if (!xen_io_tlb_start) {
5bab7864 252 m_ret = XEN_SWIOTLB_ENOMEM;
f4b2f07b
KRW
253 goto error;
254 }
b097186f
KRW
255 xen_io_tlb_end = xen_io_tlb_start + bytes;
256 /*
257 * And replace that memory with pages under 4GB.
258 */
259 rc = xen_swiotlb_fixup(xen_io_tlb_start,
260 bytes,
261 xen_io_tlb_nslabs);
f4b2f07b 262 if (rc) {
b8277600
KRW
263 if (early)
264 free_bootmem(__pa(xen_io_tlb_start), PAGE_ALIGN(bytes));
265 else {
266 free_pages((unsigned long)xen_io_tlb_start, order);
267 xen_io_tlb_start = NULL;
268 }
5bab7864 269 m_ret = XEN_SWIOTLB_EFIXUP;
b097186f 270 goto error;
f4b2f07b 271 }
b097186f 272 start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
c468bdee 273 if (early) {
ac2cbab2
YL
274 if (swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs,
275 verbose))
276 panic("Cannot allocate SWIOTLB buffer");
c468bdee
KRW
277 rc = 0;
278 } else
b8277600 279 rc = swiotlb_late_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs);
7453c549
KRW
280
281 if (!rc)
282 swiotlb_set_max_segment(PAGE_SIZE);
283
b8277600 284 return rc;
b097186f 285error:
f4b2f07b
KRW
286 if (repeat--) {
287 xen_io_tlb_nslabs = max(1024UL, /* Min is 2MB */
288 (xen_io_tlb_nslabs >> 1));
283c0972
JP
289 pr_info("Lowering to %luMB\n",
290 (xen_io_tlb_nslabs << IO_TLB_SHIFT) >> 20);
f4b2f07b
KRW
291 goto retry;
292 }
283c0972 293 pr_err("%s (rc:%d)\n", xen_swiotlb_error(m_ret), rc);
b8277600
KRW
294 if (early)
295 panic("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);
296 else
297 free_pages((unsigned long)xen_io_tlb_start, order);
298 return rc;
b097186f 299}
dceb1a68
CH
300
301static void *
b097186f 302xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
baa676fc 303 dma_addr_t *dma_handle, gfp_t flags,
00085f1e 304 unsigned long attrs)
b097186f
KRW
305{
306 void *ret;
307 int order = get_order(size);
308 u64 dma_mask = DMA_BIT_MASK(32);
6810df88
KRW
309 phys_addr_t phys;
310 dma_addr_t dev_addr;
b097186f
KRW
311
312 /*
313 * Ignore region specifiers - the kernel's ideas of
314 * pseudo-phys memory layout has nothing to do with the
315 * machine physical layout. We can't allocate highmem
316 * because we can't return a pointer to it.
317 */
318 flags &= ~(__GFP_DMA | __GFP_HIGHMEM);
319
1b65c4e5
SS
320 /* On ARM this function returns an ioremap'ped virtual address for
321 * which virt_to_phys doesn't return the corresponding physical
322 * address. In fact on ARM virt_to_phys only works for kernel direct
323 * mapped RAM memory. Also see comment below.
324 */
325 ret = xen_alloc_coherent_pages(hwdev, size, dma_handle, flags, attrs);
b097186f 326
6810df88
KRW
327 if (!ret)
328 return ret;
329
b097186f 330 if (hwdev && hwdev->coherent_dma_mask)
b5031ed1 331 dma_mask = dma_alloc_coherent_mask(hwdev, flags);
b097186f 332
1b65c4e5
SS
333 /* At this point dma_handle is the physical address, next we are
334 * going to set it to the machine address.
335 * Do not use virt_to_phys(ret) because on ARM it doesn't correspond
336 * to *dma_handle. */
337 phys = *dma_handle;
6810df88
KRW
338 dev_addr = xen_phys_to_bus(phys);
339 if (((dev_addr + size - 1 <= dma_mask)) &&
340 !range_straddles_page_boundary(phys, size))
341 *dma_handle = dev_addr;
342 else {
1b65c4e5 343 if (xen_create_contiguous_region(phys, order,
69908907 344 fls64(dma_mask), dma_handle) != 0) {
1b65c4e5 345 xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs);
b097186f
KRW
346 return NULL;
347 }
b097186f 348 }
6810df88 349 memset(ret, 0, size);
b097186f
KRW
350 return ret;
351}
b097186f 352
dceb1a68 353static void
b097186f 354xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
00085f1e 355 dma_addr_t dev_addr, unsigned long attrs)
b097186f
KRW
356{
357 int order = get_order(size);
6810df88
KRW
358 phys_addr_t phys;
359 u64 dma_mask = DMA_BIT_MASK(32);
b097186f 360
6810df88
KRW
361 if (hwdev && hwdev->coherent_dma_mask)
362 dma_mask = hwdev->coherent_dma_mask;
363
1b65c4e5
SS
364 /* do not use virt_to_phys because on ARM it doesn't return you the
365 * physical address */
366 phys = xen_bus_to_phys(dev_addr);
6810df88 367
331ae4ce 368 if (((dev_addr + size - 1 <= dma_mask)) ||
6810df88 369 range_straddles_page_boundary(phys, size))
1b65c4e5 370 xen_destroy_contiguous_region(phys, order);
6810df88 371
1b65c4e5 372 xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);
b097186f 373}
b097186f
KRW
374
375/*
376 * Map a single buffer of the indicated size for DMA in streaming mode. The
377 * physical address to use is returned.
378 *
379 * Once the device is given the dma address, the device owns this memory until
380 * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed.
381 */
dceb1a68 382static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
b097186f
KRW
383 unsigned long offset, size_t size,
384 enum dma_data_direction dir,
00085f1e 385 unsigned long attrs)
b097186f 386{
e05ed4d1 387 phys_addr_t map, phys = page_to_phys(page) + offset;
b097186f 388 dma_addr_t dev_addr = xen_phys_to_bus(phys);
b097186f
KRW
389
390 BUG_ON(dir == DMA_NONE);
391 /*
392 * If the address happens to be in the device's DMA window,
393 * we can safely return the device addr and not worry about bounce
394 * buffering it.
395 */
396 if (dma_capable(dev, dev_addr, size) &&
a4dba130 397 !range_straddles_page_boundary(phys, size) &&
291be10f 398 !xen_arch_need_swiotlb(dev, phys, dev_addr) &&
ae7871be 399 (swiotlb_force != SWIOTLB_FORCE)) {
6cf05463
SS
400 /* we are not interested in the dma_addr returned by
401 * xen_dma_map_page, only in the potential cache flushes executed
402 * by the function. */
a0f2dee0 403 xen_dma_map_page(dev, page, dev_addr, offset, size, dir, attrs);
b097186f 404 return dev_addr;
6cf05463 405 }
b097186f
KRW
406
407 /*
408 * Oh well, have to allocate and map a bounce buffer.
409 */
2b2b614d
ZK
410 trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
411
0443fa00
AD
412 map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir,
413 attrs);
e05ed4d1 414 if (map == SWIOTLB_MAP_ERROR)
4d048dbc 415 return XEN_SWIOTLB_ERROR_CODE;
b097186f 416
f1225ee4 417 dev_addr = xen_phys_to_bus(map);
6cf05463 418 xen_dma_map_page(dev, pfn_to_page(map >> PAGE_SHIFT),
a0f2dee0 419 dev_addr, map & ~PAGE_MASK, size, dir, attrs);
b097186f
KRW
420
421 /*
422 * Ensure that the address returned is DMA'ble
423 */
76418421
AD
424 if (dma_capable(dev, dev_addr, size))
425 return dev_addr;
426
d29fa0cb
AD
427 attrs |= DMA_ATTR_SKIP_CPU_SYNC;
428 swiotlb_tbl_unmap_single(dev, map, size, dir, attrs);
76418421 429
4d048dbc 430 return XEN_SWIOTLB_ERROR_CODE;
b097186f 431}
b097186f
KRW
432
433/*
434 * Unmap a single streaming mode DMA translation. The dma_addr and size must
435 * match what was provided for in a previous xen_swiotlb_map_page call. All
436 * other usages are undefined.
437 *
438 * After this call, reads by the cpu to the buffer are guaranteed to see
439 * whatever the device wrote there.
440 */
441static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
6cf05463 442 size_t size, enum dma_data_direction dir,
00085f1e 443 unsigned long attrs)
b097186f
KRW
444{
445 phys_addr_t paddr = xen_bus_to_phys(dev_addr);
446
447 BUG_ON(dir == DMA_NONE);
448
d6883e6f 449 xen_dma_unmap_page(hwdev, dev_addr, size, dir, attrs);
6cf05463 450
b097186f
KRW
451 /* NOTE: We use dev_addr here, not paddr! */
452 if (is_xen_swiotlb_buffer(dev_addr)) {
0443fa00 453 swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs);
b097186f
KRW
454 return;
455 }
456
457 if (dir != DMA_FROM_DEVICE)
458 return;
459
460 /*
461 * phys_to_virt doesn't work with hihgmem page but we could
462 * call dma_mark_clean() with hihgmem page here. However, we
463 * are fine since dma_mark_clean() is null on POWERPC. We can
464 * make dma_mark_clean() take a physical address if necessary.
465 */
466 dma_mark_clean(phys_to_virt(paddr), size);
467}
468
dceb1a68 469static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
b097186f 470 size_t size, enum dma_data_direction dir,
00085f1e 471 unsigned long attrs)
b097186f 472{
6cf05463 473 xen_unmap_single(hwdev, dev_addr, size, dir, attrs);
b097186f 474}
b097186f
KRW
475
476/*
477 * Make physical memory consistent for a single streaming mode DMA translation
478 * after a transfer.
479 *
480 * If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer
481 * using the cpu, yet do not wish to teardown the dma mapping, you must
482 * call this function before doing so. At the next point you give the dma
483 * address back to the card, you must first perform a
484 * xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer
485 */
486static void
487xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
488 size_t size, enum dma_data_direction dir,
489 enum dma_sync_target target)
490{
491 phys_addr_t paddr = xen_bus_to_phys(dev_addr);
492
493 BUG_ON(dir == DMA_NONE);
494
6cf05463 495 if (target == SYNC_FOR_CPU)
d6883e6f 496 xen_dma_sync_single_for_cpu(hwdev, dev_addr, size, dir);
6cf05463 497
b097186f 498 /* NOTE: We use dev_addr here, not paddr! */
6cf05463 499 if (is_xen_swiotlb_buffer(dev_addr))
fbfda893 500 swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target);
6cf05463
SS
501
502 if (target == SYNC_FOR_DEVICE)
9490c6c6 503 xen_dma_sync_single_for_device(hwdev, dev_addr, size, dir);
b097186f
KRW
504
505 if (dir != DMA_FROM_DEVICE)
506 return;
507
508 dma_mark_clean(phys_to_virt(paddr), size);
509}
510
511void
512xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
513 size_t size, enum dma_data_direction dir)
514{
515 xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
516}
b097186f
KRW
517
518void
519xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
520 size_t size, enum dma_data_direction dir)
521{
522 xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
523}
dceb1a68
CH
524
525/*
526 * Unmap a set of streaming mode DMA translations. Again, cpu read rules
527 * concerning calls here are the same as for swiotlb_unmap_page() above.
528 */
529static void
530xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
531 int nelems, enum dma_data_direction dir,
532 unsigned long attrs)
533{
534 struct scatterlist *sg;
535 int i;
536
537 BUG_ON(dir == DMA_NONE);
538
539 for_each_sg(sgl, sg, nelems, i)
540 xen_unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir, attrs);
541
542}
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543
544/*
545 * Map a set of buffers described by scatterlist in streaming mode for DMA.
546 * This is the scatter-gather version of the above xen_swiotlb_map_page
547 * interface. Here the scatter gather list elements are each tagged with the
548 * appropriate dma address and length. They are obtained via
549 * sg_dma_{address,length}(SG).
550 *
551 * NOTE: An implementation may be able to use a smaller number of
552 * DMA address/length pairs than there are SG table elements.
553 * (for example via virtual mapping capabilities)
554 * The routine returns the number of addr/length pairs actually
555 * used, at most nents.
556 *
557 * Device ownership issues as mentioned above for xen_swiotlb_map_page are the
558 * same here.
559 */
dceb1a68 560static int
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561xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
562 int nelems, enum dma_data_direction dir,
00085f1e 563 unsigned long attrs)
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564{
565 struct scatterlist *sg;
566 int i;
567
568 BUG_ON(dir == DMA_NONE);
569
570 for_each_sg(sgl, sg, nelems, i) {
571 phys_addr_t paddr = sg_phys(sg);
572 dma_addr_t dev_addr = xen_phys_to_bus(paddr);
573
ae7871be 574 if (swiotlb_force == SWIOTLB_FORCE ||
291be10f 575 xen_arch_need_swiotlb(hwdev, paddr, dev_addr) ||
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576 !dma_capable(hwdev, dev_addr, sg->length) ||
577 range_straddles_page_boundary(paddr, sg->length)) {
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578 phys_addr_t map = swiotlb_tbl_map_single(hwdev,
579 start_dma_addr,
580 sg_phys(sg),
581 sg->length,
0443fa00 582 dir, attrs);
e05ed4d1 583 if (map == SWIOTLB_MAP_ERROR) {
783d0281 584 dev_warn(hwdev, "swiotlb buffer is full\n");
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585 /* Don't panic here, we expect map_sg users
586 to do proper error handling. */
0443fa00 587 attrs |= DMA_ATTR_SKIP_CPU_SYNC;
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588 xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
589 attrs);
781575cd 590 sg_dma_len(sgl) = 0;
15177608 591 return 0;
b097186f 592 }
f1225ee4 593 dev_addr = xen_phys_to_bus(map);
71bfae90 594 xen_dma_map_page(hwdev, pfn_to_page(map >> PAGE_SHIFT),
a0f2dee0 595 dev_addr,
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596 map & ~PAGE_MASK,
597 sg->length,
598 dir,
599 attrs);
f1225ee4 600 sg->dma_address = dev_addr;
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601 } else {
602 /* we are not interested in the dma_addr returned by
603 * xen_dma_map_page, only in the potential cache flushes executed
604 * by the function. */
605 xen_dma_map_page(hwdev, pfn_to_page(paddr >> PAGE_SHIFT),
a0f2dee0 606 dev_addr,
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607 paddr & ~PAGE_MASK,
608 sg->length,
609 dir,
610 attrs);
b097186f 611 sg->dma_address = dev_addr;
6cf05463 612 }
781575cd 613 sg_dma_len(sg) = sg->length;
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614 }
615 return nelems;
616}
b097186f 617
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618/*
619 * Make physical memory consistent for a set of streaming mode DMA translations
620 * after a transfer.
621 *
622 * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
623 * and usage.
624 */
625static void
626xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
627 int nelems, enum dma_data_direction dir,
628 enum dma_sync_target target)
629{
630 struct scatterlist *sg;
631 int i;
632
633 for_each_sg(sgl, sg, nelems, i)
634 xen_swiotlb_sync_single(hwdev, sg->dma_address,
781575cd 635 sg_dma_len(sg), dir, target);
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636}
637
dceb1a68 638static void
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639xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
640 int nelems, enum dma_data_direction dir)
641{
642 xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
643}
b097186f 644
dceb1a68 645static void
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646xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
647 int nelems, enum dma_data_direction dir)
648{
649 xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
650}
b097186f 651
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652/*
653 * Return whether the given device DMA address mask can be supported
654 * properly. For example, if your device can only drive the low 24-bits
655 * during bus mastering, then you would pass 0x00ffffff as the mask to
656 * this function.
657 */
dceb1a68 658static int
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659xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
660{
661 return xen_virt_to_bus(xen_io_tlb_end - 1) <= mask;
662}
eb1ddc00 663
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664/*
665 * Create userspace mapping for the DMA-coherent memory.
666 * This function should be called with the pages from the current domain only,
667 * passing pages mapped from other domains would lead to memory corruption.
668 */
dceb1a68 669static int
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670xen_swiotlb_dma_mmap(struct device *dev, struct vm_area_struct *vma,
671 void *cpu_addr, dma_addr_t dma_addr, size_t size,
672 unsigned long attrs)
673{
674#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
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675 if (xen_get_dma_ops(dev)->mmap)
676 return xen_get_dma_ops(dev)->mmap(dev, vma, cpu_addr,
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677 dma_addr, size, attrs);
678#endif
679 return dma_common_mmap(dev, vma, cpu_addr, dma_addr, size);
680}
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681
682/*
683 * This function should be called with the pages from the current domain only,
684 * passing pages mapped from other domains would lead to memory corruption.
685 */
dceb1a68 686static int
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687xen_swiotlb_get_sgtable(struct device *dev, struct sg_table *sgt,
688 void *cpu_addr, dma_addr_t handle, size_t size,
689 unsigned long attrs)
690{
691#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
d5ff5061 692 if (xen_get_dma_ops(dev)->get_sgtable) {
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693#if 0
694 /*
695 * This check verifies that the page belongs to the current domain and
696 * is not one mapped from another domain.
697 * This check is for debug only, and should not go to production build
698 */
699 unsigned long bfn = PHYS_PFN(dma_to_phys(dev, handle));
700 BUG_ON (!page_is_ram(bfn));
701#endif
d5ff5061 702 return xen_get_dma_ops(dev)->get_sgtable(dev, sgt, cpu_addr,
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703 handle, size, attrs);
704 }
705#endif
706 return dma_common_get_sgtable(dev, sgt, cpu_addr, handle, size);
707}
dceb1a68 708
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709static int xen_swiotlb_mapping_error(struct device *dev, dma_addr_t dma_addr)
710{
711 return dma_addr == XEN_SWIOTLB_ERROR_CODE;
712}
713
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714const struct dma_map_ops xen_swiotlb_dma_ops = {
715 .alloc = xen_swiotlb_alloc_coherent,
716 .free = xen_swiotlb_free_coherent,
717 .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
718 .sync_single_for_device = xen_swiotlb_sync_single_for_device,
719 .sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu,
720 .sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
721 .map_sg = xen_swiotlb_map_sg_attrs,
722 .unmap_sg = xen_swiotlb_unmap_sg_attrs,
723 .map_page = xen_swiotlb_map_page,
724 .unmap_page = xen_swiotlb_unmap_page,
725 .dma_supported = xen_swiotlb_dma_supported,
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726 .mmap = xen_swiotlb_dma_mmap,
727 .get_sgtable = xen_swiotlb_get_sgtable,
4d048dbc 728 .mapping_error = xen_swiotlb_mapping_error,
dceb1a68 729};