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 static 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 | ZPCI_TABLE_PROTECTED; 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 | ZPCI_TABLE_PROTECTED; 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 static 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 static void dma_update_cpu_trans(struct zpci_dev *zdev, void *page_addr, 118 dma_addr_t dma_addr, int flags) 119 { 120 unsigned long *entry; 121 122 entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr); 123 if (!entry) { 124 WARN_ON_ONCE(1); 125 return; 126 } 127 128 if (flags & ZPCI_PTE_INVALID) { 129 invalidate_pt_entry(entry); 130 return; 131 } else { 132 set_pt_pfaa(entry, page_addr); 133 validate_pt_entry(entry); 134 } 135 136 if (flags & ZPCI_TABLE_PROTECTED) 137 entry_set_protected(entry); 138 else 139 entry_clr_protected(entry); 140 } 141 142 static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa, 143 dma_addr_t dma_addr, size_t size, int flags) 144 { 145 unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; 146 u8 *page_addr = (u8 *) (pa & PAGE_MASK); 147 dma_addr_t start_dma_addr = dma_addr; 148 unsigned long irq_flags; 149 int i, rc = 0; 150 151 if (!nr_pages) 152 return -EINVAL; 153 154 spin_lock_irqsave(&zdev->dma_table_lock, irq_flags); 155 if (!zdev->dma_table) 156 goto no_refresh; 157 158 for (i = 0; i < nr_pages; i++) { 159 dma_update_cpu_trans(zdev, page_addr, dma_addr, flags); 160 page_addr += PAGE_SIZE; 161 dma_addr += PAGE_SIZE; 162 } 163 164 /* 165 * With zdev->tlb_refresh == 0, rpcit is not required to establish new 166 * translations when previously invalid translation-table entries are 167 * validated. With lazy unmap, it also is skipped for previously valid 168 * entries, but a global rpcit is then required before any address can 169 * be re-used, i.e. after each iommu bitmap wrap-around. 170 */ 171 if (!zdev->tlb_refresh && 172 (!s390_iommu_strict || 173 ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID))) 174 goto no_refresh; 175 176 rc = zpci_refresh_trans((u64) zdev->fh << 32, start_dma_addr, 177 nr_pages * PAGE_SIZE); 178 179 no_refresh: 180 spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags); 181 return rc; 182 } 183 184 static void dma_free_seg_table(unsigned long entry) 185 { 186 unsigned long *sto = get_rt_sto(entry); 187 int sx; 188 189 for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++) 190 if (reg_entry_isvalid(sto[sx])) 191 dma_free_page_table(get_st_pto(sto[sx])); 192 193 dma_free_cpu_table(sto); 194 } 195 196 static void dma_cleanup_tables(struct zpci_dev *zdev) 197 { 198 unsigned long *table; 199 int rtx; 200 201 if (!zdev || !zdev->dma_table) 202 return; 203 204 table = zdev->dma_table; 205 for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++) 206 if (reg_entry_isvalid(table[rtx])) 207 dma_free_seg_table(table[rtx]); 208 209 dma_free_cpu_table(table); 210 zdev->dma_table = NULL; 211 } 212 213 static unsigned long __dma_alloc_iommu(struct zpci_dev *zdev, 214 unsigned long start, int size) 215 { 216 unsigned long boundary_size; 217 218 boundary_size = ALIGN(dma_get_seg_boundary(&zdev->pdev->dev) + 1, 219 PAGE_SIZE) >> PAGE_SHIFT; 220 return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages, 221 start, size, 0, boundary_size, 0); 222 } 223 224 static unsigned long dma_alloc_iommu(struct zpci_dev *zdev, int size) 225 { 226 unsigned long offset, flags; 227 int wrap = 0; 228 229 spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags); 230 offset = __dma_alloc_iommu(zdev, zdev->next_bit, size); 231 if (offset == -1) { 232 /* wrap-around */ 233 offset = __dma_alloc_iommu(zdev, 0, size); 234 wrap = 1; 235 } 236 237 if (offset != -1) { 238 zdev->next_bit = offset + size; 239 if (!zdev->tlb_refresh && !s390_iommu_strict && wrap) 240 /* global flush after wrap-around with lazy unmap */ 241 zpci_refresh_global(zdev); 242 } 243 spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags); 244 return offset; 245 } 246 247 static void dma_free_iommu(struct zpci_dev *zdev, unsigned long offset, int size) 248 { 249 unsigned long flags; 250 251 spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags); 252 if (!zdev->iommu_bitmap) 253 goto out; 254 bitmap_clear(zdev->iommu_bitmap, offset, size); 255 /* 256 * Lazy flush for unmap: need to move next_bit to avoid address re-use 257 * until wrap-around. 258 */ 259 if (!s390_iommu_strict && offset >= zdev->next_bit) 260 zdev->next_bit = offset + size; 261 out: 262 spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags); 263 } 264 265 static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page, 266 unsigned long offset, size_t size, 267 enum dma_data_direction direction, 268 struct dma_attrs *attrs) 269 { 270 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev)); 271 unsigned long nr_pages, iommu_page_index; 272 unsigned long pa = page_to_phys(page) + offset; 273 int flags = ZPCI_PTE_VALID; 274 dma_addr_t dma_addr; 275 276 /* This rounds up number of pages based on size and offset */ 277 nr_pages = iommu_num_pages(pa, size, PAGE_SIZE); 278 iommu_page_index = dma_alloc_iommu(zdev, nr_pages); 279 if (iommu_page_index == -1) 280 goto out_err; 281 282 /* Use rounded up size */ 283 size = nr_pages * PAGE_SIZE; 284 285 dma_addr = zdev->start_dma + iommu_page_index * PAGE_SIZE; 286 if (dma_addr + size > zdev->end_dma) 287 goto out_free; 288 289 if (direction == DMA_NONE || direction == DMA_TO_DEVICE) 290 flags |= ZPCI_TABLE_PROTECTED; 291 292 if (!dma_update_trans(zdev, pa, dma_addr, size, flags)) { 293 atomic64_add(nr_pages, &zdev->mapped_pages); 294 return dma_addr + (offset & ~PAGE_MASK); 295 } 296 297 out_free: 298 dma_free_iommu(zdev, iommu_page_index, nr_pages); 299 out_err: 300 zpci_err("map error:\n"); 301 zpci_err_hex(&pa, sizeof(pa)); 302 return DMA_ERROR_CODE; 303 } 304 305 static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr, 306 size_t size, enum dma_data_direction direction, 307 struct dma_attrs *attrs) 308 { 309 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev)); 310 unsigned long iommu_page_index; 311 int npages; 312 313 npages = iommu_num_pages(dma_addr, size, PAGE_SIZE); 314 dma_addr = dma_addr & PAGE_MASK; 315 if (dma_update_trans(zdev, 0, dma_addr, npages * PAGE_SIZE, 316 ZPCI_TABLE_PROTECTED | ZPCI_PTE_INVALID)) { 317 zpci_err("unmap error:\n"); 318 zpci_err_hex(&dma_addr, sizeof(dma_addr)); 319 } 320 321 atomic64_add(npages, &zdev->unmapped_pages); 322 iommu_page_index = (dma_addr - zdev->start_dma) >> PAGE_SHIFT; 323 dma_free_iommu(zdev, iommu_page_index, npages); 324 } 325 326 static void *s390_dma_alloc(struct device *dev, size_t size, 327 dma_addr_t *dma_handle, gfp_t flag, 328 struct dma_attrs *attrs) 329 { 330 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev)); 331 struct page *page; 332 unsigned long pa; 333 dma_addr_t map; 334 335 size = PAGE_ALIGN(size); 336 page = alloc_pages(flag, get_order(size)); 337 if (!page) 338 return NULL; 339 340 pa = page_to_phys(page); 341 memset((void *) pa, 0, size); 342 343 map = s390_dma_map_pages(dev, page, pa % PAGE_SIZE, 344 size, DMA_BIDIRECTIONAL, NULL); 345 if (dma_mapping_error(dev, map)) { 346 free_pages(pa, get_order(size)); 347 return NULL; 348 } 349 350 atomic64_add(size / PAGE_SIZE, &zdev->allocated_pages); 351 if (dma_handle) 352 *dma_handle = map; 353 return (void *) pa; 354 } 355 356 static void s390_dma_free(struct device *dev, size_t size, 357 void *pa, dma_addr_t dma_handle, 358 struct dma_attrs *attrs) 359 { 360 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev)); 361 362 size = PAGE_ALIGN(size); 363 atomic64_sub(size / PAGE_SIZE, &zdev->allocated_pages); 364 s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, NULL); 365 free_pages((unsigned long) pa, get_order(size)); 366 } 367 368 static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg, 369 int nr_elements, enum dma_data_direction dir, 370 struct dma_attrs *attrs) 371 { 372 int mapped_elements = 0; 373 struct scatterlist *s; 374 int i; 375 376 for_each_sg(sg, s, nr_elements, i) { 377 struct page *page = sg_page(s); 378 s->dma_address = s390_dma_map_pages(dev, page, s->offset, 379 s->length, dir, NULL); 380 if (!dma_mapping_error(dev, s->dma_address)) { 381 s->dma_length = s->length; 382 mapped_elements++; 383 } else 384 goto unmap; 385 } 386 out: 387 return mapped_elements; 388 389 unmap: 390 for_each_sg(sg, s, mapped_elements, i) { 391 if (s->dma_address) 392 s390_dma_unmap_pages(dev, s->dma_address, s->dma_length, 393 dir, NULL); 394 s->dma_address = 0; 395 s->dma_length = 0; 396 } 397 mapped_elements = 0; 398 goto out; 399 } 400 401 static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg, 402 int nr_elements, enum dma_data_direction dir, 403 struct dma_attrs *attrs) 404 { 405 struct scatterlist *s; 406 int i; 407 408 for_each_sg(sg, s, nr_elements, i) { 409 s390_dma_unmap_pages(dev, s->dma_address, s->dma_length, dir, NULL); 410 s->dma_address = 0; 411 s->dma_length = 0; 412 } 413 } 414 415 int zpci_dma_init_device(struct zpci_dev *zdev) 416 { 417 int rc; 418 419 spin_lock_init(&zdev->iommu_bitmap_lock); 420 spin_lock_init(&zdev->dma_table_lock); 421 422 zdev->dma_table = dma_alloc_cpu_table(); 423 if (!zdev->dma_table) { 424 rc = -ENOMEM; 425 goto out_clean; 426 } 427 428 zdev->iommu_size = (unsigned long) high_memory - PAGE_OFFSET; 429 zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT; 430 zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8); 431 if (!zdev->iommu_bitmap) { 432 rc = -ENOMEM; 433 goto out_reg; 434 } 435 436 rc = zpci_register_ioat(zdev, 437 0, 438 zdev->start_dma + PAGE_OFFSET, 439 zdev->start_dma + zdev->iommu_size - 1, 440 (u64) zdev->dma_table); 441 if (rc) 442 goto out_reg; 443 return 0; 444 445 out_reg: 446 dma_free_cpu_table(zdev->dma_table); 447 out_clean: 448 return rc; 449 } 450 451 void zpci_dma_exit_device(struct zpci_dev *zdev) 452 { 453 zpci_unregister_ioat(zdev, 0); 454 dma_cleanup_tables(zdev); 455 vfree(zdev->iommu_bitmap); 456 zdev->iommu_bitmap = NULL; 457 zdev->next_bit = 0; 458 } 459 460 static int __init dma_alloc_cpu_table_caches(void) 461 { 462 dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables", 463 ZPCI_TABLE_SIZE, ZPCI_TABLE_ALIGN, 464 0, NULL); 465 if (!dma_region_table_cache) 466 return -ENOMEM; 467 468 dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables", 469 ZPCI_PT_SIZE, ZPCI_PT_ALIGN, 470 0, NULL); 471 if (!dma_page_table_cache) { 472 kmem_cache_destroy(dma_region_table_cache); 473 return -ENOMEM; 474 } 475 return 0; 476 } 477 478 int __init zpci_dma_init(void) 479 { 480 return dma_alloc_cpu_table_caches(); 481 } 482 483 void zpci_dma_exit(void) 484 { 485 kmem_cache_destroy(dma_page_table_cache); 486 kmem_cache_destroy(dma_region_table_cache); 487 } 488 489 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16) 490 491 static int __init dma_debug_do_init(void) 492 { 493 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); 494 return 0; 495 } 496 fs_initcall(dma_debug_do_init); 497 498 struct dma_map_ops s390_dma_ops = { 499 .alloc = s390_dma_alloc, 500 .free = s390_dma_free, 501 .map_sg = s390_dma_map_sg, 502 .unmap_sg = s390_dma_unmap_sg, 503 .map_page = s390_dma_map_pages, 504 .unmap_page = s390_dma_unmap_pages, 505 /* if we support direct DMA this must be conditional */ 506 .is_phys = 0, 507 /* dma_supported is unconditionally true without a callback */ 508 }; 509 EXPORT_SYMBOL_GPL(s390_dma_ops); 510 511 static int __init s390_iommu_setup(char *str) 512 { 513 if (!strncmp(str, "strict", 6)) 514 s390_iommu_strict = 1; 515 return 0; 516 } 517 518 __setup("s390_iommu=", s390_iommu_setup); 519