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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
36#include <linux/bootmem.h>
37#include <linux/dma-mapping.h>
38#include <xen/swiotlb-xen.h>
39#include <xen/page.h>
40#include <xen/xen-ops.h>
41/*
42 * Used to do a quick range check in swiotlb_tbl_unmap_single and
43 * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
44 * API.
45 */
46
47static char *xen_io_tlb_start, *xen_io_tlb_end;
48static unsigned long xen_io_tlb_nslabs;
49/*
50 * Quick lookup value of the bus address of the IOTLB.
51 */
52
53u64 start_dma_addr;
54
55static dma_addr_t xen_phys_to_bus(phys_addr_t paddr)
56{
57 return phys_to_machine(XPADDR(paddr)).maddr;
58}
59
60static phys_addr_t xen_bus_to_phys(dma_addr_t baddr)
61{
62 return machine_to_phys(XMADDR(baddr)).paddr;
63}
64
65static dma_addr_t xen_virt_to_bus(void *address)
66{
67 return xen_phys_to_bus(virt_to_phys(address));
68}
69
70static int check_pages_physically_contiguous(unsigned long pfn,
71 unsigned int offset,
72 size_t length)
73{
74 unsigned long next_mfn;
75 int i;
76 int nr_pages;
77
78 next_mfn = pfn_to_mfn(pfn);
79 nr_pages = (offset + length + PAGE_SIZE-1) >> PAGE_SHIFT;
80
81 for (i = 1; i < nr_pages; i++) {
82 if (pfn_to_mfn(++pfn) != ++next_mfn)
83 return 0;
84 }
85 return 1;
86}
87
88static int range_straddles_page_boundary(phys_addr_t p, size_t size)
89{
90 unsigned long pfn = PFN_DOWN(p);
91 unsigned int offset = p & ~PAGE_MASK;
92
93 if (offset + size <= PAGE_SIZE)
94 return 0;
95 if (check_pages_physically_contiguous(pfn, offset, size))
96 return 0;
97 return 1;
98}
99
100static int is_xen_swiotlb_buffer(dma_addr_t dma_addr)
101{
102 unsigned long mfn = PFN_DOWN(dma_addr);
103 unsigned long pfn = mfn_to_local_pfn(mfn);
104 phys_addr_t paddr;
105
106 /* If the address is outside our domain, it CAN
107 * have the same virtual address as another address
108 * in our domain. Therefore _only_ check address within our domain.
109 */
110 if (pfn_valid(pfn)) {
111 paddr = PFN_PHYS(pfn);
112 return paddr >= virt_to_phys(xen_io_tlb_start) &&
113 paddr < virt_to_phys(xen_io_tlb_end);
114 }
115 return 0;
116}
117
118static int max_dma_bits = 32;
119
120static int
121xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
122{
123 int i, rc;
124 int dma_bits;
125
126 dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
127
128 i = 0;
129 do {
130 int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE);
131
132 do {
133 rc = xen_create_contiguous_region(
134 (unsigned long)buf + (i << IO_TLB_SHIFT),
135 get_order(slabs << IO_TLB_SHIFT),
136 dma_bits);
137 } while (rc && dma_bits++ < max_dma_bits);
138 if (rc)
139 return rc;
140
141 i += slabs;
142 } while (i < nslabs);
143 return 0;
144}
145
146void __init xen_swiotlb_init(int verbose)
147{
148 unsigned long bytes;
149 int rc;
150 unsigned long nr_tbl;
151
152 nr_tbl = swioltb_nr_tbl();
153 if (nr_tbl)
154 xen_io_tlb_nslabs = nr_tbl;
155 else {
156 xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
157 xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
158 }
159
160 bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
161
162 /*
163 * Get IO TLB memory from any location.
164 */
165 xen_io_tlb_start = alloc_bootmem(bytes);
166 if (!xen_io_tlb_start)
167 panic("Cannot allocate SWIOTLB buffer");
168
169 xen_io_tlb_end = xen_io_tlb_start + bytes;
170 /*
171 * And replace that memory with pages under 4GB.
172 */
173 rc = xen_swiotlb_fixup(xen_io_tlb_start,
174 bytes,
175 xen_io_tlb_nslabs);
176 if (rc)
177 goto error;
178
179 start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
180 swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);
181
182 return;
183error:
184 panic("DMA(%d): Failed to exchange pages allocated for DMA with Xen! "\
185 "We either don't have the permission or you do not have enough"\
186 "free memory under 4GB!\n", rc);
187}
188
189void *
190xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
191 dma_addr_t *dma_handle, gfp_t flags)
192{
193 void *ret;
194 int order = get_order(size);
195 u64 dma_mask = DMA_BIT_MASK(32);
196 unsigned long vstart;
197
198 /*
199 * Ignore region specifiers - the kernel's ideas of
200 * pseudo-phys memory layout has nothing to do with the
201 * machine physical layout. We can't allocate highmem
202 * because we can't return a pointer to it.
203 */
204 flags &= ~(__GFP_DMA | __GFP_HIGHMEM);
205
206 if (dma_alloc_from_coherent(hwdev, size, dma_handle, &ret))
207 return ret;
208
209 vstart = __get_free_pages(flags, order);
210 ret = (void *)vstart;
211
212 if (hwdev && hwdev->coherent_dma_mask)
213 dma_mask = dma_alloc_coherent_mask(hwdev, flags);
214
215 if (ret) {
216 if (xen_create_contiguous_region(vstart, order,
217 fls64(dma_mask)) != 0) {
218 free_pages(vstart, order);
219 return NULL;
220 }
221 memset(ret, 0, size);
222 *dma_handle = virt_to_machine(ret).maddr;
223 }
224 return ret;
225}
226EXPORT_SYMBOL_GPL(xen_swiotlb_alloc_coherent);
227
228void
229xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
230 dma_addr_t dev_addr)
231{
232 int order = get_order(size);
233
234 if (dma_release_from_coherent(hwdev, order, vaddr))
235 return;
236
237 xen_destroy_contiguous_region((unsigned long)vaddr, order);
238 free_pages((unsigned long)vaddr, order);
239}
240EXPORT_SYMBOL_GPL(xen_swiotlb_free_coherent);
241
242
243/*
244 * Map a single buffer of the indicated size for DMA in streaming mode. The
245 * physical address to use is returned.
246 *
247 * Once the device is given the dma address, the device owns this memory until
248 * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed.
249 */
250dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
251 unsigned long offset, size_t size,
252 enum dma_data_direction dir,
253 struct dma_attrs *attrs)
254{
255 phys_addr_t phys = page_to_phys(page) + offset;
256 dma_addr_t dev_addr = xen_phys_to_bus(phys);
257 void *map;
258
259 BUG_ON(dir == DMA_NONE);
260 /*
261 * If the address happens to be in the device's DMA window,
262 * we can safely return the device addr and not worry about bounce
263 * buffering it.
264 */
265 if (dma_capable(dev, dev_addr, size) &&
266 !range_straddles_page_boundary(phys, size) && !swiotlb_force)
267 return dev_addr;
268
269 /*
270 * Oh well, have to allocate and map a bounce buffer.
271 */
272 map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir);
273 if (!map)
274 return DMA_ERROR_CODE;
275
276 dev_addr = xen_virt_to_bus(map);
277
278 /*
279 * Ensure that the address returned is DMA'ble
280 */
281 if (!dma_capable(dev, dev_addr, size))
282 panic("map_single: bounce buffer is not DMA'ble");
283
284 return dev_addr;
285}
286EXPORT_SYMBOL_GPL(xen_swiotlb_map_page);
287
288/*
289 * Unmap a single streaming mode DMA translation. The dma_addr and size must
290 * match what was provided for in a previous xen_swiotlb_map_page call. All
291 * other usages are undefined.
292 *
293 * After this call, reads by the cpu to the buffer are guaranteed to see
294 * whatever the device wrote there.
295 */
296static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
297 size_t size, enum dma_data_direction dir)
298{
299 phys_addr_t paddr = xen_bus_to_phys(dev_addr);
300
301 BUG_ON(dir == DMA_NONE);
302
303 /* NOTE: We use dev_addr here, not paddr! */
304 if (is_xen_swiotlb_buffer(dev_addr)) {
305 swiotlb_tbl_unmap_single(hwdev, phys_to_virt(paddr), size, dir);
306 return;
307 }
308
309 if (dir != DMA_FROM_DEVICE)
310 return;
311
312 /*
313 * phys_to_virt doesn't work with hihgmem page but we could
314 * call dma_mark_clean() with hihgmem page here. However, we
315 * are fine since dma_mark_clean() is null on POWERPC. We can
316 * make dma_mark_clean() take a physical address if necessary.
317 */
318 dma_mark_clean(phys_to_virt(paddr), size);
319}
320
321void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
322 size_t size, enum dma_data_direction dir,
323 struct dma_attrs *attrs)
324{
325 xen_unmap_single(hwdev, dev_addr, size, dir);
326}
327EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_page);
328
329/*
330 * Make physical memory consistent for a single streaming mode DMA translation
331 * after a transfer.
332 *
333 * If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer
334 * using the cpu, yet do not wish to teardown the dma mapping, you must
335 * call this function before doing so. At the next point you give the dma
336 * address back to the card, you must first perform a
337 * xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer
338 */
339static void
340xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
341 size_t size, enum dma_data_direction dir,
342 enum dma_sync_target target)
343{
344 phys_addr_t paddr = xen_bus_to_phys(dev_addr);
345
346 BUG_ON(dir == DMA_NONE);
347
348 /* NOTE: We use dev_addr here, not paddr! */
349 if (is_xen_swiotlb_buffer(dev_addr)) {
350 swiotlb_tbl_sync_single(hwdev, phys_to_virt(paddr), size, dir,
351 target);
352 return;
353 }
354
355 if (dir != DMA_FROM_DEVICE)
356 return;
357
358 dma_mark_clean(phys_to_virt(paddr), size);
359}
360
361void
362xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
363 size_t size, enum dma_data_direction dir)
364{
365 xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
366}
367EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_cpu);
368
369void
370xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
371 size_t size, enum dma_data_direction dir)
372{
373 xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
374}
375EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_device);
376
377/*
378 * Map a set of buffers described by scatterlist in streaming mode for DMA.
379 * This is the scatter-gather version of the above xen_swiotlb_map_page
380 * interface. Here the scatter gather list elements are each tagged with the
381 * appropriate dma address and length. They are obtained via
382 * sg_dma_{address,length}(SG).
383 *
384 * NOTE: An implementation may be able to use a smaller number of
385 * DMA address/length pairs than there are SG table elements.
386 * (for example via virtual mapping capabilities)
387 * The routine returns the number of addr/length pairs actually
388 * used, at most nents.
389 *
390 * Device ownership issues as mentioned above for xen_swiotlb_map_page are the
391 * same here.
392 */
393int
394xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
395 int nelems, enum dma_data_direction dir,
396 struct dma_attrs *attrs)
397{
398 struct scatterlist *sg;
399 int i;
400
401 BUG_ON(dir == DMA_NONE);
402
403 for_each_sg(sgl, sg, nelems, i) {
404 phys_addr_t paddr = sg_phys(sg);
405 dma_addr_t dev_addr = xen_phys_to_bus(paddr);
406
407 if (swiotlb_force ||
408 !dma_capable(hwdev, dev_addr, sg->length) ||
409 range_straddles_page_boundary(paddr, sg->length)) {
410 void *map = swiotlb_tbl_map_single(hwdev,
411 start_dma_addr,
412 sg_phys(sg),
413 sg->length, dir);
414 if (!map) {
415 /* Don't panic here, we expect map_sg users
416 to do proper error handling. */
417 xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
418 attrs);
419 sgl[0].dma_length = 0;
420 return DMA_ERROR_CODE;
421 }
422 sg->dma_address = xen_virt_to_bus(map);
423 } else
424 sg->dma_address = dev_addr;
425 sg->dma_length = sg->length;
426 }
427 return nelems;
428}
429EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg_attrs);
430
431int
432xen_swiotlb_map_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
433 enum dma_data_direction dir)
434{
435 return xen_swiotlb_map_sg_attrs(hwdev, sgl, nelems, dir, NULL);
436}
437EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg);
438
439/*
440 * Unmap a set of streaming mode DMA translations. Again, cpu read rules
441 * concerning calls here are the same as for swiotlb_unmap_page() above.
442 */
443void
444xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
445 int nelems, enum dma_data_direction dir,
446 struct dma_attrs *attrs)
447{
448 struct scatterlist *sg;
449 int i;
450
451 BUG_ON(dir == DMA_NONE);
452
453 for_each_sg(sgl, sg, nelems, i)
454 xen_unmap_single(hwdev, sg->dma_address, sg->dma_length, dir);
455
456}
457EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg_attrs);
458
459void
460xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
461 enum dma_data_direction dir)
462{
463 return xen_swiotlb_unmap_sg_attrs(hwdev, sgl, nelems, dir, NULL);
464}
465EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg);
466
467/*
468 * Make physical memory consistent for a set of streaming mode DMA translations
469 * after a transfer.
470 *
471 * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
472 * and usage.
473 */
474static void
475xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
476 int nelems, enum dma_data_direction dir,
477 enum dma_sync_target target)
478{
479 struct scatterlist *sg;
480 int i;
481
482 for_each_sg(sgl, sg, nelems, i)
483 xen_swiotlb_sync_single(hwdev, sg->dma_address,
484 sg->dma_length, dir, target);
485}
486
487void
488xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
489 int nelems, enum dma_data_direction dir)
490{
491 xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
492}
493EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_cpu);
494
495void
496xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
497 int nelems, enum dma_data_direction dir)
498{
499 xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
500}
501EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_device);
502
503int
504xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
505{
506 return !dma_addr;
507}
508EXPORT_SYMBOL_GPL(xen_swiotlb_dma_mapping_error);
509
510/*
511 * Return whether the given device DMA address mask can be supported
512 * properly. For example, if your device can only drive the low 24-bits
513 * during bus mastering, then you would pass 0x00ffffff as the mask to
514 * this function.
515 */
516int
517xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
518{
519 return xen_virt_to_bus(xen_io_tlb_end - 1) <= mask;
520}
521EXPORT_SYMBOL_GPL(xen_swiotlb_dma_supported);
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
36#include <linux/bootmem.h>
37#include <linux/dma-mapping.h>
38#include <linux/export.h>
39#include <xen/swiotlb-xen.h>
40#include <xen/page.h>
41#include <xen/xen-ops.h>
42#include <xen/hvc-console.h>
43/*
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
46 * API.
47 */
48
49static char *xen_io_tlb_start, *xen_io_tlb_end;
50static unsigned long xen_io_tlb_nslabs;
51/*
52 * Quick lookup value of the bus address of the IOTLB.
53 */
54
55u64 start_dma_addr;
56
57static dma_addr_t xen_phys_to_bus(phys_addr_t paddr)
58{
59 return phys_to_machine(XPADDR(paddr)).maddr;
60}
61
62static phys_addr_t xen_bus_to_phys(dma_addr_t baddr)
63{
64 return machine_to_phys(XMADDR(baddr)).paddr;
65}
66
67static dma_addr_t xen_virt_to_bus(void *address)
68{
69 return xen_phys_to_bus(virt_to_phys(address));
70}
71
72static int check_pages_physically_contiguous(unsigned long pfn,
73 unsigned int offset,
74 size_t length)
75{
76 unsigned long next_mfn;
77 int i;
78 int nr_pages;
79
80 next_mfn = pfn_to_mfn(pfn);
81 nr_pages = (offset + length + PAGE_SIZE-1) >> PAGE_SHIFT;
82
83 for (i = 1; i < nr_pages; i++) {
84 if (pfn_to_mfn(++pfn) != ++next_mfn)
85 return 0;
86 }
87 return 1;
88}
89
90static int range_straddles_page_boundary(phys_addr_t p, size_t size)
91{
92 unsigned long pfn = PFN_DOWN(p);
93 unsigned int offset = p & ~PAGE_MASK;
94
95 if (offset + size <= PAGE_SIZE)
96 return 0;
97 if (check_pages_physically_contiguous(pfn, offset, size))
98 return 0;
99 return 1;
100}
101
102static int is_xen_swiotlb_buffer(dma_addr_t dma_addr)
103{
104 unsigned long mfn = PFN_DOWN(dma_addr);
105 unsigned long pfn = mfn_to_local_pfn(mfn);
106 phys_addr_t paddr;
107
108 /* If the address is outside our domain, it CAN
109 * have the same virtual address as another address
110 * in our domain. Therefore _only_ check address within our domain.
111 */
112 if (pfn_valid(pfn)) {
113 paddr = PFN_PHYS(pfn);
114 return paddr >= virt_to_phys(xen_io_tlb_start) &&
115 paddr < virt_to_phys(xen_io_tlb_end);
116 }
117 return 0;
118}
119
120static int max_dma_bits = 32;
121
122static int
123xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
124{
125 int i, rc;
126 int dma_bits;
127
128 dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
129
130 i = 0;
131 do {
132 int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE);
133
134 do {
135 rc = xen_create_contiguous_region(
136 (unsigned long)buf + (i << IO_TLB_SHIFT),
137 get_order(slabs << IO_TLB_SHIFT),
138 dma_bits);
139 } while (rc && dma_bits++ < max_dma_bits);
140 if (rc)
141 return rc;
142
143 i += slabs;
144 } while (i < nslabs);
145 return 0;
146}
147
148void __init xen_swiotlb_init(int verbose)
149{
150 unsigned long bytes;
151 int rc = -ENOMEM;
152 unsigned long nr_tbl;
153 char *m = NULL;
154 unsigned int repeat = 3;
155
156 nr_tbl = swiotlb_nr_tbl();
157 if (nr_tbl)
158 xen_io_tlb_nslabs = nr_tbl;
159 else {
160 xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
161 xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
162 }
163retry:
164 bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
165
166 /*
167 * Get IO TLB memory from any location.
168 */
169 xen_io_tlb_start = alloc_bootmem_pages(PAGE_ALIGN(bytes));
170 if (!xen_io_tlb_start) {
171 m = "Cannot allocate Xen-SWIOTLB buffer!\n";
172 goto error;
173 }
174 xen_io_tlb_end = xen_io_tlb_start + bytes;
175 /*
176 * And replace that memory with pages under 4GB.
177 */
178 rc = xen_swiotlb_fixup(xen_io_tlb_start,
179 bytes,
180 xen_io_tlb_nslabs);
181 if (rc) {
182 free_bootmem(__pa(xen_io_tlb_start), PAGE_ALIGN(bytes));
183 m = "Failed to get contiguous memory for DMA from Xen!\n"\
184 "You either: don't have the permissions, do not have"\
185 " enough free memory under 4GB, or the hypervisor memory"\
186 "is too fragmented!";
187 goto error;
188 }
189 start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
190 swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);
191
192 return;
193error:
194 if (repeat--) {
195 xen_io_tlb_nslabs = max(1024UL, /* Min is 2MB */
196 (xen_io_tlb_nslabs >> 1));
197 printk(KERN_INFO "Xen-SWIOTLB: Lowering to %luMB\n",
198 (xen_io_tlb_nslabs << IO_TLB_SHIFT) >> 20);
199 goto retry;
200 }
201 xen_raw_printk("%s (rc:%d)", m, rc);
202 panic("%s (rc:%d)", m, rc);
203}
204
205void *
206xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
207 dma_addr_t *dma_handle, gfp_t flags,
208 struct dma_attrs *attrs)
209{
210 void *ret;
211 int order = get_order(size);
212 u64 dma_mask = DMA_BIT_MASK(32);
213 unsigned long vstart;
214 phys_addr_t phys;
215 dma_addr_t dev_addr;
216
217 /*
218 * Ignore region specifiers - the kernel's ideas of
219 * pseudo-phys memory layout has nothing to do with the
220 * machine physical layout. We can't allocate highmem
221 * because we can't return a pointer to it.
222 */
223 flags &= ~(__GFP_DMA | __GFP_HIGHMEM);
224
225 if (dma_alloc_from_coherent(hwdev, size, dma_handle, &ret))
226 return ret;
227
228 vstart = __get_free_pages(flags, order);
229 ret = (void *)vstart;
230
231 if (!ret)
232 return ret;
233
234 if (hwdev && hwdev->coherent_dma_mask)
235 dma_mask = dma_alloc_coherent_mask(hwdev, flags);
236
237 phys = virt_to_phys(ret);
238 dev_addr = xen_phys_to_bus(phys);
239 if (((dev_addr + size - 1 <= dma_mask)) &&
240 !range_straddles_page_boundary(phys, size))
241 *dma_handle = dev_addr;
242 else {
243 if (xen_create_contiguous_region(vstart, order,
244 fls64(dma_mask)) != 0) {
245 free_pages(vstart, order);
246 return NULL;
247 }
248 *dma_handle = virt_to_machine(ret).maddr;
249 }
250 memset(ret, 0, size);
251 return ret;
252}
253EXPORT_SYMBOL_GPL(xen_swiotlb_alloc_coherent);
254
255void
256xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
257 dma_addr_t dev_addr, struct dma_attrs *attrs)
258{
259 int order = get_order(size);
260 phys_addr_t phys;
261 u64 dma_mask = DMA_BIT_MASK(32);
262
263 if (dma_release_from_coherent(hwdev, order, vaddr))
264 return;
265
266 if (hwdev && hwdev->coherent_dma_mask)
267 dma_mask = hwdev->coherent_dma_mask;
268
269 phys = virt_to_phys(vaddr);
270
271 if (((dev_addr + size - 1 > dma_mask)) ||
272 range_straddles_page_boundary(phys, size))
273 xen_destroy_contiguous_region((unsigned long)vaddr, order);
274
275 free_pages((unsigned long)vaddr, order);
276}
277EXPORT_SYMBOL_GPL(xen_swiotlb_free_coherent);
278
279
280/*
281 * Map a single buffer of the indicated size for DMA in streaming mode. The
282 * physical address to use is returned.
283 *
284 * Once the device is given the dma address, the device owns this memory until
285 * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed.
286 */
287dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
288 unsigned long offset, size_t size,
289 enum dma_data_direction dir,
290 struct dma_attrs *attrs)
291{
292 phys_addr_t phys = page_to_phys(page) + offset;
293 dma_addr_t dev_addr = xen_phys_to_bus(phys);
294 void *map;
295
296 BUG_ON(dir == DMA_NONE);
297 /*
298 * If the address happens to be in the device's DMA window,
299 * we can safely return the device addr and not worry about bounce
300 * buffering it.
301 */
302 if (dma_capable(dev, dev_addr, size) &&
303 !range_straddles_page_boundary(phys, size) && !swiotlb_force)
304 return dev_addr;
305
306 /*
307 * Oh well, have to allocate and map a bounce buffer.
308 */
309 map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir);
310 if (!map)
311 return DMA_ERROR_CODE;
312
313 dev_addr = xen_virt_to_bus(map);
314
315 /*
316 * Ensure that the address returned is DMA'ble
317 */
318 if (!dma_capable(dev, dev_addr, size)) {
319 swiotlb_tbl_unmap_single(dev, map, size, dir);
320 dev_addr = 0;
321 }
322 return dev_addr;
323}
324EXPORT_SYMBOL_GPL(xen_swiotlb_map_page);
325
326/*
327 * Unmap a single streaming mode DMA translation. The dma_addr and size must
328 * match what was provided for in a previous xen_swiotlb_map_page call. All
329 * other usages are undefined.
330 *
331 * After this call, reads by the cpu to the buffer are guaranteed to see
332 * whatever the device wrote there.
333 */
334static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
335 size_t size, enum dma_data_direction dir)
336{
337 phys_addr_t paddr = xen_bus_to_phys(dev_addr);
338
339 BUG_ON(dir == DMA_NONE);
340
341 /* NOTE: We use dev_addr here, not paddr! */
342 if (is_xen_swiotlb_buffer(dev_addr)) {
343 swiotlb_tbl_unmap_single(hwdev, phys_to_virt(paddr), size, dir);
344 return;
345 }
346
347 if (dir != DMA_FROM_DEVICE)
348 return;
349
350 /*
351 * phys_to_virt doesn't work with hihgmem page but we could
352 * call dma_mark_clean() with hihgmem page here. However, we
353 * are fine since dma_mark_clean() is null on POWERPC. We can
354 * make dma_mark_clean() take a physical address if necessary.
355 */
356 dma_mark_clean(phys_to_virt(paddr), size);
357}
358
359void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
360 size_t size, enum dma_data_direction dir,
361 struct dma_attrs *attrs)
362{
363 xen_unmap_single(hwdev, dev_addr, size, dir);
364}
365EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_page);
366
367/*
368 * Make physical memory consistent for a single streaming mode DMA translation
369 * after a transfer.
370 *
371 * If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer
372 * using the cpu, yet do not wish to teardown the dma mapping, you must
373 * call this function before doing so. At the next point you give the dma
374 * address back to the card, you must first perform a
375 * xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer
376 */
377static void
378xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
379 size_t size, enum dma_data_direction dir,
380 enum dma_sync_target target)
381{
382 phys_addr_t paddr = xen_bus_to_phys(dev_addr);
383
384 BUG_ON(dir == DMA_NONE);
385
386 /* NOTE: We use dev_addr here, not paddr! */
387 if (is_xen_swiotlb_buffer(dev_addr)) {
388 swiotlb_tbl_sync_single(hwdev, phys_to_virt(paddr), size, dir,
389 target);
390 return;
391 }
392
393 if (dir != DMA_FROM_DEVICE)
394 return;
395
396 dma_mark_clean(phys_to_virt(paddr), size);
397}
398
399void
400xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
401 size_t size, enum dma_data_direction dir)
402{
403 xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
404}
405EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_cpu);
406
407void
408xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
409 size_t size, enum dma_data_direction dir)
410{
411 xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
412}
413EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_device);
414
415/*
416 * Map a set of buffers described by scatterlist in streaming mode for DMA.
417 * This is the scatter-gather version of the above xen_swiotlb_map_page
418 * interface. Here the scatter gather list elements are each tagged with the
419 * appropriate dma address and length. They are obtained via
420 * sg_dma_{address,length}(SG).
421 *
422 * NOTE: An implementation may be able to use a smaller number of
423 * DMA address/length pairs than there are SG table elements.
424 * (for example via virtual mapping capabilities)
425 * The routine returns the number of addr/length pairs actually
426 * used, at most nents.
427 *
428 * Device ownership issues as mentioned above for xen_swiotlb_map_page are the
429 * same here.
430 */
431int
432xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
433 int nelems, enum dma_data_direction dir,
434 struct dma_attrs *attrs)
435{
436 struct scatterlist *sg;
437 int i;
438
439 BUG_ON(dir == DMA_NONE);
440
441 for_each_sg(sgl, sg, nelems, i) {
442 phys_addr_t paddr = sg_phys(sg);
443 dma_addr_t dev_addr = xen_phys_to_bus(paddr);
444
445 if (swiotlb_force ||
446 !dma_capable(hwdev, dev_addr, sg->length) ||
447 range_straddles_page_boundary(paddr, sg->length)) {
448 void *map = swiotlb_tbl_map_single(hwdev,
449 start_dma_addr,
450 sg_phys(sg),
451 sg->length, dir);
452 if (!map) {
453 /* Don't panic here, we expect map_sg users
454 to do proper error handling. */
455 xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
456 attrs);
457 sgl[0].dma_length = 0;
458 return DMA_ERROR_CODE;
459 }
460 sg->dma_address = xen_virt_to_bus(map);
461 } else
462 sg->dma_address = dev_addr;
463 sg->dma_length = sg->length;
464 }
465 return nelems;
466}
467EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg_attrs);
468
469int
470xen_swiotlb_map_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
471 enum dma_data_direction dir)
472{
473 return xen_swiotlb_map_sg_attrs(hwdev, sgl, nelems, dir, NULL);
474}
475EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg);
476
477/*
478 * Unmap a set of streaming mode DMA translations. Again, cpu read rules
479 * concerning calls here are the same as for swiotlb_unmap_page() above.
480 */
481void
482xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
483 int nelems, enum dma_data_direction dir,
484 struct dma_attrs *attrs)
485{
486 struct scatterlist *sg;
487 int i;
488
489 BUG_ON(dir == DMA_NONE);
490
491 for_each_sg(sgl, sg, nelems, i)
492 xen_unmap_single(hwdev, sg->dma_address, sg->dma_length, dir);
493
494}
495EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg_attrs);
496
497void
498xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
499 enum dma_data_direction dir)
500{
501 return xen_swiotlb_unmap_sg_attrs(hwdev, sgl, nelems, dir, NULL);
502}
503EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg);
504
505/*
506 * Make physical memory consistent for a set of streaming mode DMA translations
507 * after a transfer.
508 *
509 * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
510 * and usage.
511 */
512static void
513xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
514 int nelems, enum dma_data_direction dir,
515 enum dma_sync_target target)
516{
517 struct scatterlist *sg;
518 int i;
519
520 for_each_sg(sgl, sg, nelems, i)
521 xen_swiotlb_sync_single(hwdev, sg->dma_address,
522 sg->dma_length, dir, target);
523}
524
525void
526xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
527 int nelems, enum dma_data_direction dir)
528{
529 xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
530}
531EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_cpu);
532
533void
534xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
535 int nelems, enum dma_data_direction dir)
536{
537 xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
538}
539EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_device);
540
541int
542xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
543{
544 return !dma_addr;
545}
546EXPORT_SYMBOL_GPL(xen_swiotlb_dma_mapping_error);
547
548/*
549 * Return whether the given device DMA address mask can be supported
550 * properly. For example, if your device can only drive the low 24-bits
551 * during bus mastering, then you would pass 0x00ffffff as the mask to
552 * this function.
553 */
554int
555xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
556{
557 return xen_virt_to_bus(xen_io_tlb_end - 1) <= mask;
558}
559EXPORT_SYMBOL_GPL(xen_swiotlb_dma_supported);