1 /* 2 * Copyright IBM Corp. 2012 3 * 4 * Author(s): 5 * Jan Glauber <jang@linux.vnet.ibm.com> 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/slab.h> 10 #include <linux/export.h> 11 #include <linux/iommu-helper.h> 12 #include <linux/dma-mapping.h> 13 #include <linux/vmalloc.h> 14 #include <linux/pci.h> 15 #include <asm/pci_dma.h> 16 17 static struct kmem_cache *dma_region_table_cache; 18 static struct kmem_cache *dma_page_table_cache; 19 static int s390_iommu_strict; 20 21 static int zpci_refresh_global(struct zpci_dev *zdev) 22 { 23 return zpci_refresh_trans((u64) zdev->fh << 32, zdev->start_dma, 24 zdev->iommu_pages * PAGE_SIZE); 25 } 26 27 unsigned long *dma_alloc_cpu_table(void) 28 { 29 unsigned long *table, *entry; 30 31 table = kmem_cache_alloc(dma_region_table_cache, GFP_ATOMIC); 32 if (!table) 33 return NULL; 34 35 for (entry = table; entry < table + ZPCI_TABLE_ENTRIES; entry++) 36 *entry = ZPCI_TABLE_INVALID; 37 return table; 38 } 39 40 static void dma_free_cpu_table(void *table) 41 { 42 kmem_cache_free(dma_region_table_cache, table); 43 } 44 45 static unsigned long *dma_alloc_page_table(void) 46 { 47 unsigned long *table, *entry; 48 49 table = kmem_cache_alloc(dma_page_table_cache, GFP_ATOMIC); 50 if (!table) 51 return NULL; 52 53 for (entry = table; entry < table + ZPCI_PT_ENTRIES; entry++) 54 *entry = ZPCI_PTE_INVALID; 55 return table; 56 } 57 58 static void dma_free_page_table(void *table) 59 { 60 kmem_cache_free(dma_page_table_cache, table); 61 } 62 63 static unsigned long *dma_get_seg_table_origin(unsigned long *entry) 64 { 65 unsigned long *sto; 66 67 if (reg_entry_isvalid(*entry)) 68 sto = get_rt_sto(*entry); 69 else { 70 sto = dma_alloc_cpu_table(); 71 if (!sto) 72 return NULL; 73 74 set_rt_sto(entry, sto); 75 validate_rt_entry(entry); 76 entry_clr_protected(entry); 77 } 78 return sto; 79 } 80 81 static unsigned long *dma_get_page_table_origin(unsigned long *entry) 82 { 83 unsigned long *pto; 84 85 if (reg_entry_isvalid(*entry)) 86 pto = get_st_pto(*entry); 87 else { 88 pto = dma_alloc_page_table(); 89 if (!pto) 90 return NULL; 91 set_st_pto(entry, pto); 92 validate_st_entry(entry); 93 entry_clr_protected(entry); 94 } 95 return pto; 96 } 97 98 unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr) 99 { 100 unsigned long *sto, *pto; 101 unsigned int rtx, sx, px; 102 103 rtx = calc_rtx(dma_addr); 104 sto = dma_get_seg_table_origin(&rto[rtx]); 105 if (!sto) 106 return NULL; 107 108 sx = calc_sx(dma_addr); 109 pto = dma_get_page_table_origin(&sto[sx]); 110 if (!pto) 111 return NULL; 112 113 px = calc_px(dma_addr); 114 return &pto[px]; 115 } 116 117 void dma_update_cpu_trans(unsigned long *entry, void *page_addr, int flags) 118 { 119 if (flags & ZPCI_PTE_INVALID) { 120 invalidate_pt_entry(entry); 121 } else { 122 set_pt_pfaa(entry, page_addr); 123 validate_pt_entry(entry); 124 } 125 126 if (flags & ZPCI_TABLE_PROTECTED) 127 entry_set_protected(entry); 128 else 129 entry_clr_protected(entry); 130 } 131 132 static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa, 133 dma_addr_t dma_addr, size_t size, int flags) 134 { 135 unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; 136 u8 *page_addr = (u8 *) (pa & PAGE_MASK); 137 dma_addr_t start_dma_addr = dma_addr; 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 no_refresh; 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 } 161 162 /* 163 * With zdev->tlb_refresh == 0, rpcit is not required to establish new 164 * translations when previously invalid translation-table entries are 165 * validated. With lazy unmap, it also is skipped for previously valid 166 * entries, but a global rpcit is then required before any address can 167 * be re-used, i.e. after each iommu bitmap wrap-around. 168 */ 169 if (!zdev->tlb_refresh && 170 (!s390_iommu_strict || 171 ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID))) 172 goto no_refresh; 173 174 rc = zpci_refresh_trans((u64) zdev->fh << 32, start_dma_addr, 175 nr_pages * PAGE_SIZE); 176 undo_cpu_trans: 177 if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) { 178 flags = ZPCI_PTE_INVALID; 179 while (i-- > 0) { 180 page_addr -= PAGE_SIZE; 181 dma_addr -= PAGE_SIZE; 182 entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr); 183 if (!entry) 184 break; 185 dma_update_cpu_trans(entry, page_addr, flags); 186 } 187 } 188 189 no_refresh: 190 spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags); 191 return rc; 192 } 193 194 void dma_free_seg_table(unsigned long entry) 195 { 196 unsigned long *sto = get_rt_sto(entry); 197 int sx; 198 199 for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++) 200 if (reg_entry_isvalid(sto[sx])) 201 dma_free_page_table(get_st_pto(sto[sx])); 202 203 dma_free_cpu_table(sto); 204 } 205 206 void dma_cleanup_tables(unsigned long *table) 207 { 208 int rtx; 209 210 if (!table) 211 return; 212 213 for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++) 214 if (reg_entry_isvalid(table[rtx])) 215 dma_free_seg_table(table[rtx]); 216 217 dma_free_cpu_table(table); 218 } 219 220 static unsigned long __dma_alloc_iommu(struct zpci_dev *zdev, 221 unsigned long start, int size) 222 { 223 unsigned long boundary_size; 224 225 boundary_size = ALIGN(dma_get_seg_boundary(&zdev->pdev->dev) + 1, 226 PAGE_SIZE) >> PAGE_SHIFT; 227 return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages, 228 start, size, 0, boundary_size, 0); 229 } 230 231 static unsigned long dma_alloc_iommu(struct zpci_dev *zdev, int size) 232 { 233 unsigned long offset, flags; 234 int wrap = 0; 235 236 spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags); 237 offset = __dma_alloc_iommu(zdev, zdev->next_bit, size); 238 if (offset == -1) { 239 /* wrap-around */ 240 offset = __dma_alloc_iommu(zdev, 0, size); 241 wrap = 1; 242 } 243 244 if (offset != -1) { 245 zdev->next_bit = offset + size; 246 if (!zdev->tlb_refresh && !s390_iommu_strict && wrap) 247 /* global flush after wrap-around with lazy unmap */ 248 zpci_refresh_global(zdev); 249 } 250 spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags); 251 return offset; 252 } 253 254 static void dma_free_iommu(struct zpci_dev *zdev, unsigned long offset, int size) 255 { 256 unsigned long flags; 257 258 spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags); 259 if (!zdev->iommu_bitmap) 260 goto out; 261 bitmap_clear(zdev->iommu_bitmap, offset, size); 262 /* 263 * Lazy flush for unmap: need to move next_bit to avoid address re-use 264 * until wrap-around. 265 */ 266 if (!s390_iommu_strict && offset >= zdev->next_bit) 267 zdev->next_bit = offset + size; 268 out: 269 spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags); 270 } 271 272 static inline void zpci_err_dma(unsigned long rc, unsigned long addr) 273 { 274 struct { 275 unsigned long rc; 276 unsigned long addr; 277 } __packed data = {rc, addr}; 278 279 zpci_err_hex(&data, sizeof(data)); 280 } 281 282 static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page, 283 unsigned long offset, size_t size, 284 enum dma_data_direction direction, 285 struct dma_attrs *attrs) 286 { 287 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev)); 288 unsigned long nr_pages, iommu_page_index; 289 unsigned long pa = page_to_phys(page) + offset; 290 int flags = ZPCI_PTE_VALID; 291 dma_addr_t dma_addr; 292 int ret; 293 294 /* This rounds up number of pages based on size and offset */ 295 nr_pages = iommu_num_pages(pa, size, PAGE_SIZE); 296 iommu_page_index = dma_alloc_iommu(zdev, nr_pages); 297 if (iommu_page_index == -1) { 298 ret = -ENOSPC; 299 goto out_err; 300 } 301 302 /* Use rounded up size */ 303 size = nr_pages * PAGE_SIZE; 304 305 dma_addr = zdev->start_dma + iommu_page_index * PAGE_SIZE; 306 if (dma_addr + size > zdev->end_dma) { 307 ret = -ERANGE; 308 goto out_free; 309 } 310 311 if (direction == DMA_NONE || direction == DMA_TO_DEVICE) 312 flags |= ZPCI_TABLE_PROTECTED; 313 314 ret = dma_update_trans(zdev, pa, dma_addr, size, flags); 315 if (ret) 316 goto out_free; 317 318 atomic64_add(nr_pages, &zdev->mapped_pages); 319 return dma_addr + (offset & ~PAGE_MASK); 320 321 out_free: 322 dma_free_iommu(zdev, iommu_page_index, nr_pages); 323 out_err: 324 zpci_err("map error:\n"); 325 zpci_err_dma(ret, pa); 326 return DMA_ERROR_CODE; 327 } 328 329 static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr, 330 size_t size, enum dma_data_direction direction, 331 struct dma_attrs *attrs) 332 { 333 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev)); 334 unsigned long iommu_page_index; 335 int npages, ret; 336 337 npages = iommu_num_pages(dma_addr, size, PAGE_SIZE); 338 dma_addr = dma_addr & PAGE_MASK; 339 ret = dma_update_trans(zdev, 0, dma_addr, npages * PAGE_SIZE, 340 ZPCI_PTE_INVALID); 341 if (ret) { 342 zpci_err("unmap error:\n"); 343 zpci_err_dma(ret, dma_addr); 344 return; 345 } 346 347 atomic64_add(npages, &zdev->unmapped_pages); 348 iommu_page_index = (dma_addr - zdev->start_dma) >> PAGE_SHIFT; 349 dma_free_iommu(zdev, iommu_page_index, npages); 350 } 351 352 static void *s390_dma_alloc(struct device *dev, size_t size, 353 dma_addr_t *dma_handle, gfp_t flag, 354 struct dma_attrs *attrs) 355 { 356 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev)); 357 struct page *page; 358 unsigned long pa; 359 dma_addr_t map; 360 361 size = PAGE_ALIGN(size); 362 page = alloc_pages(flag, get_order(size)); 363 if (!page) 364 return NULL; 365 366 pa = page_to_phys(page); 367 memset((void *) pa, 0, size); 368 369 map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, NULL); 370 if (dma_mapping_error(dev, map)) { 371 free_pages(pa, get_order(size)); 372 return NULL; 373 } 374 375 atomic64_add(size / PAGE_SIZE, &zdev->allocated_pages); 376 if (dma_handle) 377 *dma_handle = map; 378 return (void *) pa; 379 } 380 381 static void s390_dma_free(struct device *dev, size_t size, 382 void *pa, dma_addr_t dma_handle, 383 struct dma_attrs *attrs) 384 { 385 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev)); 386 387 size = PAGE_ALIGN(size); 388 atomic64_sub(size / PAGE_SIZE, &zdev->allocated_pages); 389 s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, NULL); 390 free_pages((unsigned long) pa, get_order(size)); 391 } 392 393 static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg, 394 int nr_elements, enum dma_data_direction dir, 395 struct dma_attrs *attrs) 396 { 397 int mapped_elements = 0; 398 struct scatterlist *s; 399 int i; 400 401 for_each_sg(sg, s, nr_elements, i) { 402 struct page *page = sg_page(s); 403 s->dma_address = s390_dma_map_pages(dev, page, s->offset, 404 s->length, dir, NULL); 405 if (!dma_mapping_error(dev, s->dma_address)) { 406 s->dma_length = s->length; 407 mapped_elements++; 408 } else 409 goto unmap; 410 } 411 out: 412 return mapped_elements; 413 414 unmap: 415 for_each_sg(sg, s, mapped_elements, i) { 416 if (s->dma_address) 417 s390_dma_unmap_pages(dev, s->dma_address, s->dma_length, 418 dir, NULL); 419 s->dma_address = 0; 420 s->dma_length = 0; 421 } 422 mapped_elements = 0; 423 goto out; 424 } 425 426 static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg, 427 int nr_elements, enum dma_data_direction dir, 428 struct dma_attrs *attrs) 429 { 430 struct scatterlist *s; 431 int i; 432 433 for_each_sg(sg, s, nr_elements, i) { 434 s390_dma_unmap_pages(dev, s->dma_address, s->dma_length, dir, NULL); 435 s->dma_address = 0; 436 s->dma_length = 0; 437 } 438 } 439 440 int zpci_dma_init_device(struct zpci_dev *zdev) 441 { 442 int rc; 443 444 /* 445 * At this point, if the device is part of an IOMMU domain, this would 446 * be a strong hint towards a bug in the IOMMU API (common) code and/or 447 * simultaneous access via IOMMU and DMA API. So let's issue a warning. 448 */ 449 WARN_ON(zdev->s390_domain); 450 451 spin_lock_init(&zdev->iommu_bitmap_lock); 452 spin_lock_init(&zdev->dma_table_lock); 453 454 zdev->dma_table = dma_alloc_cpu_table(); 455 if (!zdev->dma_table) { 456 rc = -ENOMEM; 457 goto out_clean; 458 } 459 460 /* 461 * Restrict the iommu bitmap size to the minimum of the following: 462 * - main memory size 463 * - 3-level pagetable address limit minus start_dma offset 464 * - DMA address range allowed by the hardware (clp query pci fn) 465 * 466 * Also set zdev->end_dma to the actual end address of the usable 467 * range, instead of the theoretical maximum as reported by hardware. 468 */ 469 zdev->iommu_size = min3((u64) high_memory, 470 ZPCI_TABLE_SIZE_RT - zdev->start_dma, 471 zdev->end_dma - zdev->start_dma + 1); 472 zdev->end_dma = zdev->start_dma + zdev->iommu_size - 1; 473 zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT; 474 zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8); 475 if (!zdev->iommu_bitmap) { 476 rc = -ENOMEM; 477 goto out_reg; 478 } 479 480 rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma, 481 (u64) zdev->dma_table); 482 if (rc) 483 goto out_reg; 484 return 0; 485 486 out_reg: 487 dma_free_cpu_table(zdev->dma_table); 488 out_clean: 489 return rc; 490 } 491 492 void zpci_dma_exit_device(struct zpci_dev *zdev) 493 { 494 /* 495 * At this point, if the device is part of an IOMMU domain, this would 496 * be a strong hint towards a bug in the IOMMU API (common) code and/or 497 * simultaneous access via IOMMU and DMA API. So let's issue a warning. 498 */ 499 WARN_ON(zdev->s390_domain); 500 501 zpci_unregister_ioat(zdev, 0); 502 dma_cleanup_tables(zdev->dma_table); 503 zdev->dma_table = NULL; 504 vfree(zdev->iommu_bitmap); 505 zdev->iommu_bitmap = NULL; 506 zdev->next_bit = 0; 507 } 508 509 static int __init dma_alloc_cpu_table_caches(void) 510 { 511 dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables", 512 ZPCI_TABLE_SIZE, ZPCI_TABLE_ALIGN, 513 0, NULL); 514 if (!dma_region_table_cache) 515 return -ENOMEM; 516 517 dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables", 518 ZPCI_PT_SIZE, ZPCI_PT_ALIGN, 519 0, NULL); 520 if (!dma_page_table_cache) { 521 kmem_cache_destroy(dma_region_table_cache); 522 return -ENOMEM; 523 } 524 return 0; 525 } 526 527 int __init zpci_dma_init(void) 528 { 529 return dma_alloc_cpu_table_caches(); 530 } 531 532 void zpci_dma_exit(void) 533 { 534 kmem_cache_destroy(dma_page_table_cache); 535 kmem_cache_destroy(dma_region_table_cache); 536 } 537 538 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16) 539 540 static int __init dma_debug_do_init(void) 541 { 542 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); 543 return 0; 544 } 545 fs_initcall(dma_debug_do_init); 546 547 struct dma_map_ops s390_dma_ops = { 548 .alloc = s390_dma_alloc, 549 .free = s390_dma_free, 550 .map_sg = s390_dma_map_sg, 551 .unmap_sg = s390_dma_unmap_sg, 552 .map_page = s390_dma_map_pages, 553 .unmap_page = s390_dma_unmap_pages, 554 /* if we support direct DMA this must be conditional */ 555 .is_phys = 0, 556 /* dma_supported is unconditionally true without a callback */ 557 }; 558 EXPORT_SYMBOL_GPL(s390_dma_ops); 559 560 static int __init s390_iommu_setup(char *str) 561 { 562 if (!strncmp(str, "strict", 6)) 563 s390_iommu_strict = 1; 564 return 0; 565 } 566 567 __setup("s390_iommu=", s390_iommu_setup); 568