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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright IBM Corp. 2012
4 *
5 * Author(s):
6 * Jan Glauber <jang@linux.vnet.ibm.com>
7 */
8
9#include <linux/kernel.h>
10#include <linux/slab.h>
11#include <linux/export.h>
12#include <linux/iommu-helper.h>
13#include <linux/dma-map-ops.h>
14#include <linux/vmalloc.h>
15#include <linux/pci.h>
16#include <asm/pci_dma.h>
17
18static struct kmem_cache *dma_region_table_cache;
19static struct kmem_cache *dma_page_table_cache;
20static int s390_iommu_strict;
21
22static int zpci_refresh_global(struct zpci_dev *zdev)
23{
24 return zpci_refresh_trans((u64) zdev->fh << 32, zdev->start_dma,
25 zdev->iommu_pages * PAGE_SIZE);
26}
27
28unsigned long *dma_alloc_cpu_table(void)
29{
30 unsigned long *table, *entry;
31
32 table = kmem_cache_alloc(dma_region_table_cache, GFP_ATOMIC);
33 if (!table)
34 return NULL;
35
36 for (entry = table; entry < table + ZPCI_TABLE_ENTRIES; entry++)
37 *entry = ZPCI_TABLE_INVALID;
38 return table;
39}
40
41static void dma_free_cpu_table(void *table)
42{
43 kmem_cache_free(dma_region_table_cache, table);
44}
45
46static unsigned long *dma_alloc_page_table(void)
47{
48 unsigned long *table, *entry;
49
50 table = kmem_cache_alloc(dma_page_table_cache, GFP_ATOMIC);
51 if (!table)
52 return NULL;
53
54 for (entry = table; entry < table + ZPCI_PT_ENTRIES; entry++)
55 *entry = ZPCI_PTE_INVALID;
56 return table;
57}
58
59static void dma_free_page_table(void *table)
60{
61 kmem_cache_free(dma_page_table_cache, table);
62}
63
64static unsigned long *dma_get_seg_table_origin(unsigned long *entry)
65{
66 unsigned long *sto;
67
68 if (reg_entry_isvalid(*entry))
69 sto = get_rt_sto(*entry);
70 else {
71 sto = dma_alloc_cpu_table();
72 if (!sto)
73 return NULL;
74
75 set_rt_sto(entry, sto);
76 validate_rt_entry(entry);
77 entry_clr_protected(entry);
78 }
79 return sto;
80}
81
82static unsigned long *dma_get_page_table_origin(unsigned long *entry)
83{
84 unsigned long *pto;
85
86 if (reg_entry_isvalid(*entry))
87 pto = get_st_pto(*entry);
88 else {
89 pto = dma_alloc_page_table();
90 if (!pto)
91 return NULL;
92 set_st_pto(entry, pto);
93 validate_st_entry(entry);
94 entry_clr_protected(entry);
95 }
96 return pto;
97}
98
99unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr)
100{
101 unsigned long *sto, *pto;
102 unsigned int rtx, sx, px;
103
104 rtx = calc_rtx(dma_addr);
105 sto = dma_get_seg_table_origin(&rto[rtx]);
106 if (!sto)
107 return NULL;
108
109 sx = calc_sx(dma_addr);
110 pto = dma_get_page_table_origin(&sto[sx]);
111 if (!pto)
112 return NULL;
113
114 px = calc_px(dma_addr);
115 return &pto[px];
116}
117
118void dma_update_cpu_trans(unsigned long *entry, void *page_addr, int flags)
119{
120 if (flags & ZPCI_PTE_INVALID) {
121 invalidate_pt_entry(entry);
122 } else {
123 set_pt_pfaa(entry, page_addr);
124 validate_pt_entry(entry);
125 }
126
127 if (flags & ZPCI_TABLE_PROTECTED)
128 entry_set_protected(entry);
129 else
130 entry_clr_protected(entry);
131}
132
133static int __dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
134 dma_addr_t dma_addr, size_t size, int flags)
135{
136 unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
137 u8 *page_addr = (u8 *) (pa & PAGE_MASK);
138 unsigned long irq_flags;
139 unsigned long *entry;
140 int i, rc = 0;
141
142 if (!nr_pages)
143 return -EINVAL;
144
145 spin_lock_irqsave(&zdev->dma_table_lock, irq_flags);
146 if (!zdev->dma_table) {
147 rc = -EINVAL;
148 goto out_unlock;
149 }
150
151 for (i = 0; i < nr_pages; i++) {
152 entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
153 if (!entry) {
154 rc = -ENOMEM;
155 goto undo_cpu_trans;
156 }
157 dma_update_cpu_trans(entry, page_addr, flags);
158 page_addr += PAGE_SIZE;
159 dma_addr += PAGE_SIZE;
160 }
161
162undo_cpu_trans:
163 if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
164 flags = ZPCI_PTE_INVALID;
165 while (i-- > 0) {
166 page_addr -= PAGE_SIZE;
167 dma_addr -= PAGE_SIZE;
168 entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
169 if (!entry)
170 break;
171 dma_update_cpu_trans(entry, page_addr, flags);
172 }
173 }
174out_unlock:
175 spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags);
176 return rc;
177}
178
179static int __dma_purge_tlb(struct zpci_dev *zdev, dma_addr_t dma_addr,
180 size_t size, int flags)
181{
182 unsigned long irqflags;
183 int ret;
184
185 /*
186 * With zdev->tlb_refresh == 0, rpcit is not required to establish new
187 * translations when previously invalid translation-table entries are
188 * validated. With lazy unmap, rpcit is skipped for previously valid
189 * entries, but a global rpcit is then required before any address can
190 * be re-used, i.e. after each iommu bitmap wrap-around.
191 */
192 if ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID) {
193 if (!zdev->tlb_refresh)
194 return 0;
195 } else {
196 if (!s390_iommu_strict)
197 return 0;
198 }
199
200 ret = zpci_refresh_trans((u64) zdev->fh << 32, dma_addr,
201 PAGE_ALIGN(size));
202 if (ret == -ENOMEM && !s390_iommu_strict) {
203 /* enable the hypervisor to free some resources */
204 if (zpci_refresh_global(zdev))
205 goto out;
206
207 spin_lock_irqsave(&zdev->iommu_bitmap_lock, irqflags);
208 bitmap_andnot(zdev->iommu_bitmap, zdev->iommu_bitmap,
209 zdev->lazy_bitmap, zdev->iommu_pages);
210 bitmap_zero(zdev->lazy_bitmap, zdev->iommu_pages);
211 spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, irqflags);
212 ret = 0;
213 }
214out:
215 return ret;
216}
217
218static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
219 dma_addr_t dma_addr, size_t size, int flags)
220{
221 int rc;
222
223 rc = __dma_update_trans(zdev, pa, dma_addr, size, flags);
224 if (rc)
225 return rc;
226
227 rc = __dma_purge_tlb(zdev, dma_addr, size, flags);
228 if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID))
229 __dma_update_trans(zdev, pa, dma_addr, size, ZPCI_PTE_INVALID);
230
231 return rc;
232}
233
234void dma_free_seg_table(unsigned long entry)
235{
236 unsigned long *sto = get_rt_sto(entry);
237 int sx;
238
239 for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++)
240 if (reg_entry_isvalid(sto[sx]))
241 dma_free_page_table(get_st_pto(sto[sx]));
242
243 dma_free_cpu_table(sto);
244}
245
246void dma_cleanup_tables(unsigned long *table)
247{
248 int rtx;
249
250 if (!table)
251 return;
252
253 for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
254 if (reg_entry_isvalid(table[rtx]))
255 dma_free_seg_table(table[rtx]);
256
257 dma_free_cpu_table(table);
258}
259
260static unsigned long __dma_alloc_iommu(struct device *dev,
261 unsigned long start, int size)
262{
263 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
264
265 return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
266 start, size, zdev->start_dma >> PAGE_SHIFT,
267 dma_get_seg_boundary_nr_pages(dev, PAGE_SHIFT),
268 0);
269}
270
271static dma_addr_t dma_alloc_address(struct device *dev, int size)
272{
273 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
274 unsigned long offset, flags;
275
276 spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
277 offset = __dma_alloc_iommu(dev, zdev->next_bit, size);
278 if (offset == -1) {
279 if (!s390_iommu_strict) {
280 /* global flush before DMA addresses are reused */
281 if (zpci_refresh_global(zdev))
282 goto out_error;
283
284 bitmap_andnot(zdev->iommu_bitmap, zdev->iommu_bitmap,
285 zdev->lazy_bitmap, zdev->iommu_pages);
286 bitmap_zero(zdev->lazy_bitmap, zdev->iommu_pages);
287 }
288 /* wrap-around */
289 offset = __dma_alloc_iommu(dev, 0, size);
290 if (offset == -1)
291 goto out_error;
292 }
293 zdev->next_bit = offset + size;
294 spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
295
296 return zdev->start_dma + offset * PAGE_SIZE;
297
298out_error:
299 spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
300 return DMA_MAPPING_ERROR;
301}
302
303static void dma_free_address(struct device *dev, dma_addr_t dma_addr, int size)
304{
305 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
306 unsigned long flags, offset;
307
308 offset = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
309
310 spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
311 if (!zdev->iommu_bitmap)
312 goto out;
313
314 if (s390_iommu_strict)
315 bitmap_clear(zdev->iommu_bitmap, offset, size);
316 else
317 bitmap_set(zdev->lazy_bitmap, offset, size);
318
319out:
320 spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
321}
322
323static inline void zpci_err_dma(unsigned long rc, unsigned long addr)
324{
325 struct {
326 unsigned long rc;
327 unsigned long addr;
328 } __packed data = {rc, addr};
329
330 zpci_err_hex(&data, sizeof(data));
331}
332
333static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
334 unsigned long offset, size_t size,
335 enum dma_data_direction direction,
336 unsigned long attrs)
337{
338 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
339 unsigned long pa = page_to_phys(page) + offset;
340 int flags = ZPCI_PTE_VALID;
341 unsigned long nr_pages;
342 dma_addr_t dma_addr;
343 int ret;
344
345 /* This rounds up number of pages based on size and offset */
346 nr_pages = iommu_num_pages(pa, size, PAGE_SIZE);
347 dma_addr = dma_alloc_address(dev, nr_pages);
348 if (dma_addr == DMA_MAPPING_ERROR) {
349 ret = -ENOSPC;
350 goto out_err;
351 }
352
353 /* Use rounded up size */
354 size = nr_pages * PAGE_SIZE;
355
356 if (direction == DMA_NONE || direction == DMA_TO_DEVICE)
357 flags |= ZPCI_TABLE_PROTECTED;
358
359 ret = dma_update_trans(zdev, pa, dma_addr, size, flags);
360 if (ret)
361 goto out_free;
362
363 atomic64_add(nr_pages, &zdev->mapped_pages);
364 return dma_addr + (offset & ~PAGE_MASK);
365
366out_free:
367 dma_free_address(dev, dma_addr, nr_pages);
368out_err:
369 zpci_err("map error:\n");
370 zpci_err_dma(ret, pa);
371 return DMA_MAPPING_ERROR;
372}
373
374static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
375 size_t size, enum dma_data_direction direction,
376 unsigned long attrs)
377{
378 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
379 int npages, ret;
380
381 npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
382 dma_addr = dma_addr & PAGE_MASK;
383 ret = dma_update_trans(zdev, 0, dma_addr, npages * PAGE_SIZE,
384 ZPCI_PTE_INVALID);
385 if (ret) {
386 zpci_err("unmap error:\n");
387 zpci_err_dma(ret, dma_addr);
388 return;
389 }
390
391 atomic64_add(npages, &zdev->unmapped_pages);
392 dma_free_address(dev, dma_addr, npages);
393}
394
395static void *s390_dma_alloc(struct device *dev, size_t size,
396 dma_addr_t *dma_handle, gfp_t flag,
397 unsigned long attrs)
398{
399 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
400 struct page *page;
401 unsigned long pa;
402 dma_addr_t map;
403
404 size = PAGE_ALIGN(size);
405 page = alloc_pages(flag | __GFP_ZERO, get_order(size));
406 if (!page)
407 return NULL;
408
409 pa = page_to_phys(page);
410 map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, 0);
411 if (dma_mapping_error(dev, map)) {
412 free_pages(pa, get_order(size));
413 return NULL;
414 }
415
416 atomic64_add(size / PAGE_SIZE, &zdev->allocated_pages);
417 if (dma_handle)
418 *dma_handle = map;
419 return (void *) pa;
420}
421
422static void s390_dma_free(struct device *dev, size_t size,
423 void *pa, dma_addr_t dma_handle,
424 unsigned long attrs)
425{
426 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
427
428 size = PAGE_ALIGN(size);
429 atomic64_sub(size / PAGE_SIZE, &zdev->allocated_pages);
430 s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, 0);
431 free_pages((unsigned long) pa, get_order(size));
432}
433
434/* Map a segment into a contiguous dma address area */
435static int __s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
436 size_t size, dma_addr_t *handle,
437 enum dma_data_direction dir)
438{
439 unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
440 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
441 dma_addr_t dma_addr_base, dma_addr;
442 int flags = ZPCI_PTE_VALID;
443 struct scatterlist *s;
444 unsigned long pa = 0;
445 int ret;
446
447 dma_addr_base = dma_alloc_address(dev, nr_pages);
448 if (dma_addr_base == DMA_MAPPING_ERROR)
449 return -ENOMEM;
450
451 dma_addr = dma_addr_base;
452 if (dir == DMA_NONE || dir == DMA_TO_DEVICE)
453 flags |= ZPCI_TABLE_PROTECTED;
454
455 for (s = sg; dma_addr < dma_addr_base + size; s = sg_next(s)) {
456 pa = page_to_phys(sg_page(s));
457 ret = __dma_update_trans(zdev, pa, dma_addr,
458 s->offset + s->length, flags);
459 if (ret)
460 goto unmap;
461
462 dma_addr += s->offset + s->length;
463 }
464 ret = __dma_purge_tlb(zdev, dma_addr_base, size, flags);
465 if (ret)
466 goto unmap;
467
468 *handle = dma_addr_base;
469 atomic64_add(nr_pages, &zdev->mapped_pages);
470
471 return ret;
472
473unmap:
474 dma_update_trans(zdev, 0, dma_addr_base, dma_addr - dma_addr_base,
475 ZPCI_PTE_INVALID);
476 dma_free_address(dev, dma_addr_base, nr_pages);
477 zpci_err("map error:\n");
478 zpci_err_dma(ret, pa);
479 return ret;
480}
481
482static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
483 int nr_elements, enum dma_data_direction dir,
484 unsigned long attrs)
485{
486 struct scatterlist *s = sg, *start = sg, *dma = sg;
487 unsigned int max = dma_get_max_seg_size(dev);
488 unsigned int size = s->offset + s->length;
489 unsigned int offset = s->offset;
490 int count = 0, i;
491
492 for (i = 1; i < nr_elements; i++) {
493 s = sg_next(s);
494
495 s->dma_address = DMA_MAPPING_ERROR;
496 s->dma_length = 0;
497
498 if (s->offset || (size & ~PAGE_MASK) ||
499 size + s->length > max) {
500 if (__s390_dma_map_sg(dev, start, size,
501 &dma->dma_address, dir))
502 goto unmap;
503
504 dma->dma_address += offset;
505 dma->dma_length = size - offset;
506
507 size = offset = s->offset;
508 start = s;
509 dma = sg_next(dma);
510 count++;
511 }
512 size += s->length;
513 }
514 if (__s390_dma_map_sg(dev, start, size, &dma->dma_address, dir))
515 goto unmap;
516
517 dma->dma_address += offset;
518 dma->dma_length = size - offset;
519
520 return count + 1;
521unmap:
522 for_each_sg(sg, s, count, i)
523 s390_dma_unmap_pages(dev, sg_dma_address(s), sg_dma_len(s),
524 dir, attrs);
525
526 return 0;
527}
528
529static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
530 int nr_elements, enum dma_data_direction dir,
531 unsigned long attrs)
532{
533 struct scatterlist *s;
534 int i;
535
536 for_each_sg(sg, s, nr_elements, i) {
537 if (s->dma_length)
538 s390_dma_unmap_pages(dev, s->dma_address, s->dma_length,
539 dir, attrs);
540 s->dma_address = 0;
541 s->dma_length = 0;
542 }
543}
544
545int zpci_dma_init_device(struct zpci_dev *zdev)
546{
547 int rc;
548
549 /*
550 * At this point, if the device is part of an IOMMU domain, this would
551 * be a strong hint towards a bug in the IOMMU API (common) code and/or
552 * simultaneous access via IOMMU and DMA API. So let's issue a warning.
553 */
554 WARN_ON(zdev->s390_domain);
555
556 spin_lock_init(&zdev->iommu_bitmap_lock);
557 spin_lock_init(&zdev->dma_table_lock);
558
559 zdev->dma_table = dma_alloc_cpu_table();
560 if (!zdev->dma_table) {
561 rc = -ENOMEM;
562 goto out;
563 }
564
565 /*
566 * Restrict the iommu bitmap size to the minimum of the following:
567 * - main memory size
568 * - 3-level pagetable address limit minus start_dma offset
569 * - DMA address range allowed by the hardware (clp query pci fn)
570 *
571 * Also set zdev->end_dma to the actual end address of the usable
572 * range, instead of the theoretical maximum as reported by hardware.
573 */
574 zdev->start_dma = PAGE_ALIGN(zdev->start_dma);
575 zdev->iommu_size = min3((u64) high_memory,
576 ZPCI_TABLE_SIZE_RT - zdev->start_dma,
577 zdev->end_dma - zdev->start_dma + 1);
578 zdev->end_dma = zdev->start_dma + zdev->iommu_size - 1;
579 zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT;
580 zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8);
581 if (!zdev->iommu_bitmap) {
582 rc = -ENOMEM;
583 goto free_dma_table;
584 }
585 if (!s390_iommu_strict) {
586 zdev->lazy_bitmap = vzalloc(zdev->iommu_pages / 8);
587 if (!zdev->lazy_bitmap) {
588 rc = -ENOMEM;
589 goto free_bitmap;
590 }
591
592 }
593 rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
594 (u64) zdev->dma_table);
595 if (rc)
596 goto free_bitmap;
597
598 return 0;
599free_bitmap:
600 vfree(zdev->iommu_bitmap);
601 zdev->iommu_bitmap = NULL;
602 vfree(zdev->lazy_bitmap);
603 zdev->lazy_bitmap = NULL;
604free_dma_table:
605 dma_free_cpu_table(zdev->dma_table);
606 zdev->dma_table = NULL;
607out:
608 return rc;
609}
610
611void zpci_dma_exit_device(struct zpci_dev *zdev)
612{
613 /*
614 * At this point, if the device is part of an IOMMU domain, this would
615 * be a strong hint towards a bug in the IOMMU API (common) code and/or
616 * simultaneous access via IOMMU and DMA API. So let's issue a warning.
617 */
618 WARN_ON(zdev->s390_domain);
619
620 if (zpci_unregister_ioat(zdev, 0))
621 return;
622
623 dma_cleanup_tables(zdev->dma_table);
624 zdev->dma_table = NULL;
625 vfree(zdev->iommu_bitmap);
626 zdev->iommu_bitmap = NULL;
627 vfree(zdev->lazy_bitmap);
628 zdev->lazy_bitmap = NULL;
629
630 zdev->next_bit = 0;
631}
632
633static int __init dma_alloc_cpu_table_caches(void)
634{
635 dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables",
636 ZPCI_TABLE_SIZE, ZPCI_TABLE_ALIGN,
637 0, NULL);
638 if (!dma_region_table_cache)
639 return -ENOMEM;
640
641 dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables",
642 ZPCI_PT_SIZE, ZPCI_PT_ALIGN,
643 0, NULL);
644 if (!dma_page_table_cache) {
645 kmem_cache_destroy(dma_region_table_cache);
646 return -ENOMEM;
647 }
648 return 0;
649}
650
651int __init zpci_dma_init(void)
652{
653 return dma_alloc_cpu_table_caches();
654}
655
656void zpci_dma_exit(void)
657{
658 kmem_cache_destroy(dma_page_table_cache);
659 kmem_cache_destroy(dma_region_table_cache);
660}
661
662const struct dma_map_ops s390_pci_dma_ops = {
663 .alloc = s390_dma_alloc,
664 .free = s390_dma_free,
665 .map_sg = s390_dma_map_sg,
666 .unmap_sg = s390_dma_unmap_sg,
667 .map_page = s390_dma_map_pages,
668 .unmap_page = s390_dma_unmap_pages,
669 .mmap = dma_common_mmap,
670 .get_sgtable = dma_common_get_sgtable,
671 .alloc_pages = dma_common_alloc_pages,
672 .free_pages = dma_common_free_pages,
673 /* dma_supported is unconditionally true without a callback */
674};
675EXPORT_SYMBOL_GPL(s390_pci_dma_ops);
676
677static int __init s390_iommu_setup(char *str)
678{
679 if (!strcmp(str, "strict"))
680 s390_iommu_strict = 1;
681 return 1;
682}
683
684__setup("s390_iommu=", s390_iommu_setup);