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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-mapping.h>
14#include <linux/vmalloc.h>
15#include <linux/pci.h>
16#include <asm/pci_dma.h>
17
18#define S390_MAPPING_ERROR (~(dma_addr_t) 0x0)
19
20static struct kmem_cache *dma_region_table_cache;
21static struct kmem_cache *dma_page_table_cache;
22static int s390_iommu_strict;
23
24static int zpci_refresh_global(struct zpci_dev *zdev)
25{
26 return zpci_refresh_trans((u64) zdev->fh << 32, zdev->start_dma,
27 zdev->iommu_pages * PAGE_SIZE);
28}
29
30unsigned long *dma_alloc_cpu_table(void)
31{
32 unsigned long *table, *entry;
33
34 table = kmem_cache_alloc(dma_region_table_cache, GFP_ATOMIC);
35 if (!table)
36 return NULL;
37
38 for (entry = table; entry < table + ZPCI_TABLE_ENTRIES; entry++)
39 *entry = ZPCI_TABLE_INVALID;
40 return table;
41}
42
43static void dma_free_cpu_table(void *table)
44{
45 kmem_cache_free(dma_region_table_cache, table);
46}
47
48static unsigned long *dma_alloc_page_table(void)
49{
50 unsigned long *table, *entry;
51
52 table = kmem_cache_alloc(dma_page_table_cache, GFP_ATOMIC);
53 if (!table)
54 return NULL;
55
56 for (entry = table; entry < table + ZPCI_PT_ENTRIES; entry++)
57 *entry = ZPCI_PTE_INVALID;
58 return table;
59}
60
61static void dma_free_page_table(void *table)
62{
63 kmem_cache_free(dma_page_table_cache, table);
64}
65
66static unsigned long *dma_get_seg_table_origin(unsigned long *entry)
67{
68 unsigned long *sto;
69
70 if (reg_entry_isvalid(*entry))
71 sto = get_rt_sto(*entry);
72 else {
73 sto = dma_alloc_cpu_table();
74 if (!sto)
75 return NULL;
76
77 set_rt_sto(entry, sto);
78 validate_rt_entry(entry);
79 entry_clr_protected(entry);
80 }
81 return sto;
82}
83
84static unsigned long *dma_get_page_table_origin(unsigned long *entry)
85{
86 unsigned long *pto;
87
88 if (reg_entry_isvalid(*entry))
89 pto = get_st_pto(*entry);
90 else {
91 pto = dma_alloc_page_table();
92 if (!pto)
93 return NULL;
94 set_st_pto(entry, pto);
95 validate_st_entry(entry);
96 entry_clr_protected(entry);
97 }
98 return pto;
99}
100
101unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr)
102{
103 unsigned long *sto, *pto;
104 unsigned int rtx, sx, px;
105
106 rtx = calc_rtx(dma_addr);
107 sto = dma_get_seg_table_origin(&rto[rtx]);
108 if (!sto)
109 return NULL;
110
111 sx = calc_sx(dma_addr);
112 pto = dma_get_page_table_origin(&sto[sx]);
113 if (!pto)
114 return NULL;
115
116 px = calc_px(dma_addr);
117 return &pto[px];
118}
119
120void dma_update_cpu_trans(unsigned long *entry, void *page_addr, int flags)
121{
122 if (flags & ZPCI_PTE_INVALID) {
123 invalidate_pt_entry(entry);
124 } else {
125 set_pt_pfaa(entry, page_addr);
126 validate_pt_entry(entry);
127 }
128
129 if (flags & ZPCI_TABLE_PROTECTED)
130 entry_set_protected(entry);
131 else
132 entry_clr_protected(entry);
133}
134
135static int __dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
136 dma_addr_t dma_addr, size_t size, int flags)
137{
138 unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
139 u8 *page_addr = (u8 *) (pa & PAGE_MASK);
140 unsigned long irq_flags;
141 unsigned long *entry;
142 int i, rc = 0;
143
144 if (!nr_pages)
145 return -EINVAL;
146
147 spin_lock_irqsave(&zdev->dma_table_lock, irq_flags);
148 if (!zdev->dma_table) {
149 rc = -EINVAL;
150 goto out_unlock;
151 }
152
153 for (i = 0; i < nr_pages; i++) {
154 entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
155 if (!entry) {
156 rc = -ENOMEM;
157 goto undo_cpu_trans;
158 }
159 dma_update_cpu_trans(entry, page_addr, flags);
160 page_addr += PAGE_SIZE;
161 dma_addr += PAGE_SIZE;
162 }
163
164undo_cpu_trans:
165 if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
166 flags = ZPCI_PTE_INVALID;
167 while (i-- > 0) {
168 page_addr -= PAGE_SIZE;
169 dma_addr -= PAGE_SIZE;
170 entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
171 if (!entry)
172 break;
173 dma_update_cpu_trans(entry, page_addr, flags);
174 }
175 }
176out_unlock:
177 spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags);
178 return rc;
179}
180
181static int __dma_purge_tlb(struct zpci_dev *zdev, dma_addr_t dma_addr,
182 size_t size, int flags)
183{
184 unsigned long irqflags;
185 int ret;
186
187 /*
188 * With zdev->tlb_refresh == 0, rpcit is not required to establish new
189 * translations when previously invalid translation-table entries are
190 * validated. With lazy unmap, rpcit is skipped for previously valid
191 * entries, but a global rpcit is then required before any address can
192 * be re-used, i.e. after each iommu bitmap wrap-around.
193 */
194 if ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID) {
195 if (!zdev->tlb_refresh)
196 return 0;
197 } else {
198 if (!s390_iommu_strict)
199 return 0;
200 }
201
202 ret = zpci_refresh_trans((u64) zdev->fh << 32, dma_addr,
203 PAGE_ALIGN(size));
204 if (ret == -ENOMEM && !s390_iommu_strict) {
205 /* enable the hypervisor to free some resources */
206 if (zpci_refresh_global(zdev))
207 goto out;
208
209 spin_lock_irqsave(&zdev->iommu_bitmap_lock, irqflags);
210 bitmap_andnot(zdev->iommu_bitmap, zdev->iommu_bitmap,
211 zdev->lazy_bitmap, zdev->iommu_pages);
212 bitmap_zero(zdev->lazy_bitmap, zdev->iommu_pages);
213 spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, irqflags);
214 ret = 0;
215 }
216out:
217 return ret;
218}
219
220static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
221 dma_addr_t dma_addr, size_t size, int flags)
222{
223 int rc;
224
225 rc = __dma_update_trans(zdev, pa, dma_addr, size, flags);
226 if (rc)
227 return rc;
228
229 rc = __dma_purge_tlb(zdev, dma_addr, size, flags);
230 if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID))
231 __dma_update_trans(zdev, pa, dma_addr, size, ZPCI_PTE_INVALID);
232
233 return rc;
234}
235
236void dma_free_seg_table(unsigned long entry)
237{
238 unsigned long *sto = get_rt_sto(entry);
239 int sx;
240
241 for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++)
242 if (reg_entry_isvalid(sto[sx]))
243 dma_free_page_table(get_st_pto(sto[sx]));
244
245 dma_free_cpu_table(sto);
246}
247
248void dma_cleanup_tables(unsigned long *table)
249{
250 int rtx;
251
252 if (!table)
253 return;
254
255 for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
256 if (reg_entry_isvalid(table[rtx]))
257 dma_free_seg_table(table[rtx]);
258
259 dma_free_cpu_table(table);
260}
261
262static unsigned long __dma_alloc_iommu(struct device *dev,
263 unsigned long start, int size)
264{
265 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
266 unsigned long boundary_size;
267
268 boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
269 PAGE_SIZE) >> PAGE_SHIFT;
270 return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
271 start, size, zdev->start_dma >> PAGE_SHIFT,
272 boundary_size, 0);
273}
274
275static dma_addr_t dma_alloc_address(struct device *dev, int size)
276{
277 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
278 unsigned long offset, flags;
279
280 spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
281 offset = __dma_alloc_iommu(dev, zdev->next_bit, size);
282 if (offset == -1) {
283 if (!s390_iommu_strict) {
284 /* global flush before DMA addresses are reused */
285 if (zpci_refresh_global(zdev))
286 goto out_error;
287
288 bitmap_andnot(zdev->iommu_bitmap, zdev->iommu_bitmap,
289 zdev->lazy_bitmap, zdev->iommu_pages);
290 bitmap_zero(zdev->lazy_bitmap, zdev->iommu_pages);
291 }
292 /* wrap-around */
293 offset = __dma_alloc_iommu(dev, 0, size);
294 if (offset == -1)
295 goto out_error;
296 }
297 zdev->next_bit = offset + size;
298 spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
299
300 return zdev->start_dma + offset * PAGE_SIZE;
301
302out_error:
303 spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
304 return S390_MAPPING_ERROR;
305}
306
307static void dma_free_address(struct device *dev, dma_addr_t dma_addr, int size)
308{
309 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
310 unsigned long flags, offset;
311
312 offset = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
313
314 spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
315 if (!zdev->iommu_bitmap)
316 goto out;
317
318 if (s390_iommu_strict)
319 bitmap_clear(zdev->iommu_bitmap, offset, size);
320 else
321 bitmap_set(zdev->lazy_bitmap, offset, size);
322
323out:
324 spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
325}
326
327static inline void zpci_err_dma(unsigned long rc, unsigned long addr)
328{
329 struct {
330 unsigned long rc;
331 unsigned long addr;
332 } __packed data = {rc, addr};
333
334 zpci_err_hex(&data, sizeof(data));
335}
336
337static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
338 unsigned long offset, size_t size,
339 enum dma_data_direction direction,
340 unsigned long attrs)
341{
342 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
343 unsigned long pa = page_to_phys(page) + offset;
344 int flags = ZPCI_PTE_VALID;
345 unsigned long nr_pages;
346 dma_addr_t dma_addr;
347 int ret;
348
349 /* This rounds up number of pages based on size and offset */
350 nr_pages = iommu_num_pages(pa, size, PAGE_SIZE);
351 dma_addr = dma_alloc_address(dev, nr_pages);
352 if (dma_addr == S390_MAPPING_ERROR) {
353 ret = -ENOSPC;
354 goto out_err;
355 }
356
357 /* Use rounded up size */
358 size = nr_pages * PAGE_SIZE;
359
360 if (direction == DMA_NONE || direction == DMA_TO_DEVICE)
361 flags |= ZPCI_TABLE_PROTECTED;
362
363 ret = dma_update_trans(zdev, pa, dma_addr, size, flags);
364 if (ret)
365 goto out_free;
366
367 atomic64_add(nr_pages, &zdev->mapped_pages);
368 return dma_addr + (offset & ~PAGE_MASK);
369
370out_free:
371 dma_free_address(dev, dma_addr, nr_pages);
372out_err:
373 zpci_err("map error:\n");
374 zpci_err_dma(ret, pa);
375 return S390_MAPPING_ERROR;
376}
377
378static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
379 size_t size, enum dma_data_direction direction,
380 unsigned long attrs)
381{
382 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
383 int npages, ret;
384
385 npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
386 dma_addr = dma_addr & PAGE_MASK;
387 ret = dma_update_trans(zdev, 0, dma_addr, npages * PAGE_SIZE,
388 ZPCI_PTE_INVALID);
389 if (ret) {
390 zpci_err("unmap error:\n");
391 zpci_err_dma(ret, dma_addr);
392 return;
393 }
394
395 atomic64_add(npages, &zdev->unmapped_pages);
396 dma_free_address(dev, dma_addr, npages);
397}
398
399static void *s390_dma_alloc(struct device *dev, size_t size,
400 dma_addr_t *dma_handle, gfp_t flag,
401 unsigned long attrs)
402{
403 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
404 struct page *page;
405 unsigned long pa;
406 dma_addr_t map;
407
408 size = PAGE_ALIGN(size);
409 page = alloc_pages(flag, get_order(size));
410 if (!page)
411 return NULL;
412
413 pa = page_to_phys(page);
414 map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, 0);
415 if (dma_mapping_error(dev, map)) {
416 free_pages(pa, get_order(size));
417 return NULL;
418 }
419
420 atomic64_add(size / PAGE_SIZE, &zdev->allocated_pages);
421 if (dma_handle)
422 *dma_handle = map;
423 return (void *) pa;
424}
425
426static void s390_dma_free(struct device *dev, size_t size,
427 void *pa, dma_addr_t dma_handle,
428 unsigned long attrs)
429{
430 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
431
432 size = PAGE_ALIGN(size);
433 atomic64_sub(size / PAGE_SIZE, &zdev->allocated_pages);
434 s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, 0);
435 free_pages((unsigned long) pa, get_order(size));
436}
437
438/* Map a segment into a contiguous dma address area */
439static int __s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
440 size_t size, dma_addr_t *handle,
441 enum dma_data_direction dir)
442{
443 unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
444 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
445 dma_addr_t dma_addr_base, dma_addr;
446 int flags = ZPCI_PTE_VALID;
447 struct scatterlist *s;
448 unsigned long pa = 0;
449 int ret;
450
451 dma_addr_base = dma_alloc_address(dev, nr_pages);
452 if (dma_addr_base == S390_MAPPING_ERROR)
453 return -ENOMEM;
454
455 dma_addr = dma_addr_base;
456 if (dir == DMA_NONE || dir == DMA_TO_DEVICE)
457 flags |= ZPCI_TABLE_PROTECTED;
458
459 for (s = sg; dma_addr < dma_addr_base + size; s = sg_next(s)) {
460 pa = page_to_phys(sg_page(s));
461 ret = __dma_update_trans(zdev, pa, dma_addr,
462 s->offset + s->length, flags);
463 if (ret)
464 goto unmap;
465
466 dma_addr += s->offset + s->length;
467 }
468 ret = __dma_purge_tlb(zdev, dma_addr_base, size, flags);
469 if (ret)
470 goto unmap;
471
472 *handle = dma_addr_base;
473 atomic64_add(nr_pages, &zdev->mapped_pages);
474
475 return ret;
476
477unmap:
478 dma_update_trans(zdev, 0, dma_addr_base, dma_addr - dma_addr_base,
479 ZPCI_PTE_INVALID);
480 dma_free_address(dev, dma_addr_base, nr_pages);
481 zpci_err("map error:\n");
482 zpci_err_dma(ret, pa);
483 return ret;
484}
485
486static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
487 int nr_elements, enum dma_data_direction dir,
488 unsigned long attrs)
489{
490 struct scatterlist *s = sg, *start = sg, *dma = sg;
491 unsigned int max = dma_get_max_seg_size(dev);
492 unsigned int size = s->offset + s->length;
493 unsigned int offset = s->offset;
494 int count = 0, i;
495
496 for (i = 1; i < nr_elements; i++) {
497 s = sg_next(s);
498
499 s->dma_address = S390_MAPPING_ERROR;
500 s->dma_length = 0;
501
502 if (s->offset || (size & ~PAGE_MASK) ||
503 size + s->length > max) {
504 if (__s390_dma_map_sg(dev, start, size,
505 &dma->dma_address, dir))
506 goto unmap;
507
508 dma->dma_address += offset;
509 dma->dma_length = size - offset;
510
511 size = offset = s->offset;
512 start = s;
513 dma = sg_next(dma);
514 count++;
515 }
516 size += s->length;
517 }
518 if (__s390_dma_map_sg(dev, start, size, &dma->dma_address, dir))
519 goto unmap;
520
521 dma->dma_address += offset;
522 dma->dma_length = size - offset;
523
524 return count + 1;
525unmap:
526 for_each_sg(sg, s, count, i)
527 s390_dma_unmap_pages(dev, sg_dma_address(s), sg_dma_len(s),
528 dir, attrs);
529
530 return 0;
531}
532
533static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
534 int nr_elements, enum dma_data_direction dir,
535 unsigned long attrs)
536{
537 struct scatterlist *s;
538 int i;
539
540 for_each_sg(sg, s, nr_elements, i) {
541 if (s->dma_length)
542 s390_dma_unmap_pages(dev, s->dma_address, s->dma_length,
543 dir, attrs);
544 s->dma_address = 0;
545 s->dma_length = 0;
546 }
547}
548
549static int s390_mapping_error(struct device *dev, dma_addr_t dma_addr)
550{
551 return dma_addr == S390_MAPPING_ERROR;
552}
553
554int zpci_dma_init_device(struct zpci_dev *zdev)
555{
556 int rc;
557
558 /*
559 * At this point, if the device is part of an IOMMU domain, this would
560 * be a strong hint towards a bug in the IOMMU API (common) code and/or
561 * simultaneous access via IOMMU and DMA API. So let's issue a warning.
562 */
563 WARN_ON(zdev->s390_domain);
564
565 spin_lock_init(&zdev->iommu_bitmap_lock);
566 spin_lock_init(&zdev->dma_table_lock);
567
568 zdev->dma_table = dma_alloc_cpu_table();
569 if (!zdev->dma_table) {
570 rc = -ENOMEM;
571 goto out;
572 }
573
574 /*
575 * Restrict the iommu bitmap size to the minimum of the following:
576 * - main memory size
577 * - 3-level pagetable address limit minus start_dma offset
578 * - DMA address range allowed by the hardware (clp query pci fn)
579 *
580 * Also set zdev->end_dma to the actual end address of the usable
581 * range, instead of the theoretical maximum as reported by hardware.
582 */
583 zdev->start_dma = PAGE_ALIGN(zdev->start_dma);
584 zdev->iommu_size = min3((u64) high_memory,
585 ZPCI_TABLE_SIZE_RT - zdev->start_dma,
586 zdev->end_dma - zdev->start_dma + 1);
587 zdev->end_dma = zdev->start_dma + zdev->iommu_size - 1;
588 zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT;
589 zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8);
590 if (!zdev->iommu_bitmap) {
591 rc = -ENOMEM;
592 goto free_dma_table;
593 }
594 if (!s390_iommu_strict) {
595 zdev->lazy_bitmap = vzalloc(zdev->iommu_pages / 8);
596 if (!zdev->lazy_bitmap) {
597 rc = -ENOMEM;
598 goto free_bitmap;
599 }
600
601 }
602 rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
603 (u64) zdev->dma_table);
604 if (rc)
605 goto free_bitmap;
606
607 return 0;
608free_bitmap:
609 vfree(zdev->iommu_bitmap);
610 zdev->iommu_bitmap = NULL;
611 vfree(zdev->lazy_bitmap);
612 zdev->lazy_bitmap = NULL;
613free_dma_table:
614 dma_free_cpu_table(zdev->dma_table);
615 zdev->dma_table = NULL;
616out:
617 return rc;
618}
619
620void zpci_dma_exit_device(struct zpci_dev *zdev)
621{
622 /*
623 * At this point, if the device is part of an IOMMU domain, this would
624 * be a strong hint towards a bug in the IOMMU API (common) code and/or
625 * simultaneous access via IOMMU and DMA API. So let's issue a warning.
626 */
627 WARN_ON(zdev->s390_domain);
628
629 if (zpci_unregister_ioat(zdev, 0))
630 return;
631
632 dma_cleanup_tables(zdev->dma_table);
633 zdev->dma_table = NULL;
634 vfree(zdev->iommu_bitmap);
635 zdev->iommu_bitmap = NULL;
636 vfree(zdev->lazy_bitmap);
637 zdev->lazy_bitmap = NULL;
638
639 zdev->next_bit = 0;
640}
641
642static int __init dma_alloc_cpu_table_caches(void)
643{
644 dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables",
645 ZPCI_TABLE_SIZE, ZPCI_TABLE_ALIGN,
646 0, NULL);
647 if (!dma_region_table_cache)
648 return -ENOMEM;
649
650 dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables",
651 ZPCI_PT_SIZE, ZPCI_PT_ALIGN,
652 0, NULL);
653 if (!dma_page_table_cache) {
654 kmem_cache_destroy(dma_region_table_cache);
655 return -ENOMEM;
656 }
657 return 0;
658}
659
660int __init zpci_dma_init(void)
661{
662 return dma_alloc_cpu_table_caches();
663}
664
665void zpci_dma_exit(void)
666{
667 kmem_cache_destroy(dma_page_table_cache);
668 kmem_cache_destroy(dma_region_table_cache);
669}
670
671#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
672
673static int __init dma_debug_do_init(void)
674{
675 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
676 return 0;
677}
678fs_initcall(dma_debug_do_init);
679
680const struct dma_map_ops s390_pci_dma_ops = {
681 .alloc = s390_dma_alloc,
682 .free = s390_dma_free,
683 .map_sg = s390_dma_map_sg,
684 .unmap_sg = s390_dma_unmap_sg,
685 .map_page = s390_dma_map_pages,
686 .unmap_page = s390_dma_unmap_pages,
687 .mapping_error = s390_mapping_error,
688 /* if we support direct DMA this must be conditional */
689 .is_phys = 0,
690 /* dma_supported is unconditionally true without a callback */
691};
692EXPORT_SYMBOL_GPL(s390_pci_dma_ops);
693
694static int __init s390_iommu_setup(char *str)
695{
696 if (!strncmp(str, "strict", 6))
697 s390_iommu_strict = 1;
698 return 0;
699}
700
701__setup("s390_iommu=", s390_iommu_setup);