drivers/char/agp/amd-k7-agp.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
amd_create_page_map
amd_free_page_map
amd_free_gatt_pages
amd_create_gatt_pages
amd_create_gatt_table
amd_free_gatt_table
amd_irongate_fetch_size
amd_irongate_configure
amd_irongate_cleanup
amd_irongate_tlbflush
amd_insert_memory
amd_remove_memory
agp_amdk7_probe
agp_amdk7_remove
agp_amdk7_suspend
agp_amdk7_resume
agp_amdk7_init
agp_amdk7_cleanup
   1 /*
   2  * AMD K7 AGPGART routines.
   3  */
   4 
   5 #include <linux/module.h>
   6 #include <linux/pci.h>
   7 #include <linux/init.h>
   8 #include <linux/agp_backend.h>
   9 #include <linux/page-flags.h>
  10 #include <linux/mm.h>
  11 #include <linux/slab.h>
  12 #include <asm/set_memory.h>
  13 #include "agp.h"
  14 
  15 #define AMD_MMBASE_BAR  1
  16 #define AMD_APSIZE      0xac
  17 #define AMD_MODECNTL    0xb0
  18 #define AMD_MODECNTL2   0xb2
  19 #define AMD_GARTENABLE  0x02    /* In mmio region (16-bit register) */
  20 #define AMD_ATTBASE     0x04    /* In mmio region (32-bit register) */
  21 #define AMD_TLBFLUSH    0x0c    /* In mmio region (32-bit register) */
  22 #define AMD_CACHEENTRY  0x10    /* In mmio region (32-bit register) */
  23 
  24 static const struct pci_device_id agp_amdk7_pci_table[];
  25 
  26 struct amd_page_map {
  27         unsigned long *real;
  28         unsigned long __iomem *remapped;
  29 };
  30 
  31 static struct _amd_irongate_private {
  32         volatile u8 __iomem *registers;
  33         struct amd_page_map **gatt_pages;
  34         int num_tables;
  35 } amd_irongate_private;
  36 
  37 static int amd_create_page_map(struct amd_page_map *page_map)
  38 {
  39         int i;
  40 
  41         page_map->real = (unsigned long *) __get_free_page(GFP_KERNEL);
  42         if (page_map->real == NULL)
  43                 return -ENOMEM;
  44 
  45         set_memory_uc((unsigned long)page_map->real, 1);
  46         page_map->remapped = page_map->real;
  47 
  48         for (i = 0; i < PAGE_SIZE / sizeof(unsigned long); i++) {
  49                 writel(agp_bridge->scratch_page, page_map->remapped+i);
  50                 readl(page_map->remapped+i);    /* PCI Posting. */
  51         }
  52 
  53         return 0;
  54 }
  55 
  56 static void amd_free_page_map(struct amd_page_map *page_map)
  57 {
  58         set_memory_wb((unsigned long)page_map->real, 1);
  59         free_page((unsigned long) page_map->real);
  60 }
  61 
  62 static void amd_free_gatt_pages(void)
  63 {
  64         int i;
  65         struct amd_page_map **tables;
  66         struct amd_page_map *entry;
  67 
  68         tables = amd_irongate_private.gatt_pages;
  69         for (i = 0; i < amd_irongate_private.num_tables; i++) {
  70                 entry = tables[i];
  71                 if (entry != NULL) {
  72                         if (entry->real != NULL)
  73                                 amd_free_page_map(entry);
  74                         kfree(entry);
  75                 }
  76         }
  77         kfree(tables);
  78         amd_irongate_private.gatt_pages = NULL;
  79 }
  80 
  81 static int amd_create_gatt_pages(int nr_tables)
  82 {
  83         struct amd_page_map **tables;
  84         struct amd_page_map *entry;
  85         int retval = 0;
  86         int i;
  87 
  88         tables = kcalloc(nr_tables + 1, sizeof(struct amd_page_map *),
  89                          GFP_KERNEL);
  90         if (tables == NULL)
  91                 return -ENOMEM;
  92 
  93         for (i = 0; i < nr_tables; i++) {
  94                 entry = kzalloc(sizeof(struct amd_page_map), GFP_KERNEL);
  95                 tables[i] = entry;
  96                 if (entry == NULL) {
  97                         retval = -ENOMEM;
  98                         break;
  99                 }
 100                 retval = amd_create_page_map(entry);
 101                 if (retval != 0)
 102                         break;
 103         }
 104         amd_irongate_private.num_tables = i;
 105         amd_irongate_private.gatt_pages = tables;
 106 
 107         if (retval != 0)
 108                 amd_free_gatt_pages();
 109 
 110         return retval;
 111 }
 112 
 113 /* Since we don't need contiguous memory we just try
 114  * to get the gatt table once
 115  */
 116 
 117 #define GET_PAGE_DIR_OFF(addr) (addr >> 22)
 118 #define GET_PAGE_DIR_IDX(addr) (GET_PAGE_DIR_OFF(addr) - \
 119         GET_PAGE_DIR_OFF(agp_bridge->gart_bus_addr))
 120 #define GET_GATT_OFF(addr) ((addr & 0x003ff000) >> 12)
 121 #define GET_GATT(addr) (amd_irongate_private.gatt_pages[\
 122         GET_PAGE_DIR_IDX(addr)]->remapped)
 123 
 124 static int amd_create_gatt_table(struct agp_bridge_data *bridge)
 125 {
 126         struct aper_size_info_lvl2 *value;
 127         struct amd_page_map page_dir;
 128         unsigned long __iomem *cur_gatt;
 129         unsigned long addr;
 130         int retval;
 131         int i;
 132 
 133         value = A_SIZE_LVL2(agp_bridge->current_size);
 134         retval = amd_create_page_map(&page_dir);
 135         if (retval != 0)
 136                 return retval;
 137 
 138         retval = amd_create_gatt_pages(value->num_entries / 1024);
 139         if (retval != 0) {
 140                 amd_free_page_map(&page_dir);
 141                 return retval;
 142         }
 143 
 144         agp_bridge->gatt_table_real = (u32 *)page_dir.real;
 145         agp_bridge->gatt_table = (u32 __iomem *)page_dir.remapped;
 146         agp_bridge->gatt_bus_addr = virt_to_phys(page_dir.real);
 147 
 148         /* Get the address for the gart region.
 149          * This is a bus address even on the alpha, b/c its
 150          * used to program the agp master not the cpu
 151          */
 152 
 153         addr = pci_bus_address(agp_bridge->dev, AGP_APERTURE_BAR);
 154         agp_bridge->gart_bus_addr = addr;
 155 
 156         /* Calculate the agp offset */
 157         for (i = 0; i < value->num_entries / 1024; i++, addr += 0x00400000) {
 158                 writel(virt_to_phys(amd_irongate_private.gatt_pages[i]->real) | 1,
 159                         page_dir.remapped+GET_PAGE_DIR_OFF(addr));
 160                 readl(page_dir.remapped+GET_PAGE_DIR_OFF(addr));        /* PCI Posting. */
 161         }
 162 
 163         for (i = 0; i < value->num_entries; i++) {
 164                 addr = (i * PAGE_SIZE) + agp_bridge->gart_bus_addr;
 165                 cur_gatt = GET_GATT(addr);
 166                 writel(agp_bridge->scratch_page, cur_gatt+GET_GATT_OFF(addr));
 167                 readl(cur_gatt+GET_GATT_OFF(addr));     /* PCI Posting. */
 168         }
 169 
 170         return 0;
 171 }
 172 
 173 static int amd_free_gatt_table(struct agp_bridge_data *bridge)
 174 {
 175         struct amd_page_map page_dir;
 176 
 177         page_dir.real = (unsigned long *)agp_bridge->gatt_table_real;
 178         page_dir.remapped = (unsigned long __iomem *)agp_bridge->gatt_table;
 179 
 180         amd_free_gatt_pages();
 181         amd_free_page_map(&page_dir);
 182         return 0;
 183 }
 184 
 185 static int amd_irongate_fetch_size(void)
 186 {
 187         int i;
 188         u32 temp;
 189         struct aper_size_info_lvl2 *values;
 190 
 191         pci_read_config_dword(agp_bridge->dev, AMD_APSIZE, &temp);
 192         temp = (temp & 0x0000000e);
 193         values = A_SIZE_LVL2(agp_bridge->driver->aperture_sizes);
 194         for (i = 0; i < agp_bridge->driver->num_aperture_sizes; i++) {
 195                 if (temp == values[i].size_value) {
 196                         agp_bridge->previous_size =
 197                             agp_bridge->current_size = (void *) (values + i);
 198 
 199                         agp_bridge->aperture_size_idx = i;
 200                         return values[i].size;
 201                 }
 202         }
 203 
 204         return 0;
 205 }
 206 
 207 static int amd_irongate_configure(void)
 208 {
 209         struct aper_size_info_lvl2 *current_size;
 210         phys_addr_t reg;
 211         u32 temp;
 212         u16 enable_reg;
 213 
 214         current_size = A_SIZE_LVL2(agp_bridge->current_size);
 215 
 216         if (!amd_irongate_private.registers) {
 217                 /* Get the memory mapped registers */
 218                 reg = pci_resource_start(agp_bridge->dev, AMD_MMBASE_BAR);
 219                 amd_irongate_private.registers = (volatile u8 __iomem *) ioremap(reg, 4096);
 220                 if (!amd_irongate_private.registers)
 221                         return -ENOMEM;
 222         }
 223 
 224         /* Write out the address of the gatt table */
 225         writel(agp_bridge->gatt_bus_addr, amd_irongate_private.registers+AMD_ATTBASE);
 226         readl(amd_irongate_private.registers+AMD_ATTBASE);      /* PCI Posting. */
 227 
 228         /* Write the Sync register */
 229         pci_write_config_byte(agp_bridge->dev, AMD_MODECNTL, 0x80);
 230 
 231         /* Set indexing mode */
 232         pci_write_config_byte(agp_bridge->dev, AMD_MODECNTL2, 0x00);
 233 
 234         /* Write the enable register */
 235         enable_reg = readw(amd_irongate_private.registers+AMD_GARTENABLE);
 236         enable_reg = (enable_reg | 0x0004);
 237         writew(enable_reg, amd_irongate_private.registers+AMD_GARTENABLE);
 238         readw(amd_irongate_private.registers+AMD_GARTENABLE);   /* PCI Posting. */
 239 
 240         /* Write out the size register */
 241         pci_read_config_dword(agp_bridge->dev, AMD_APSIZE, &temp);
 242         temp = (((temp & ~(0x0000000e)) | current_size->size_value) | 1);
 243         pci_write_config_dword(agp_bridge->dev, AMD_APSIZE, temp);
 244 
 245         /* Flush the tlb */
 246         writel(1, amd_irongate_private.registers+AMD_TLBFLUSH);
 247         readl(amd_irongate_private.registers+AMD_TLBFLUSH);     /* PCI Posting.*/
 248         return 0;
 249 }
 250 
 251 static void amd_irongate_cleanup(void)
 252 {
 253         struct aper_size_info_lvl2 *previous_size;
 254         u32 temp;
 255         u16 enable_reg;
 256 
 257         previous_size = A_SIZE_LVL2(agp_bridge->previous_size);
 258 
 259         enable_reg = readw(amd_irongate_private.registers+AMD_GARTENABLE);
 260         enable_reg = (enable_reg & ~(0x0004));
 261         writew(enable_reg, amd_irongate_private.registers+AMD_GARTENABLE);
 262         readw(amd_irongate_private.registers+AMD_GARTENABLE);   /* PCI Posting. */
 263 
 264         /* Write back the previous size and disable gart translation */
 265         pci_read_config_dword(agp_bridge->dev, AMD_APSIZE, &temp);
 266         temp = ((temp & ~(0x0000000f)) | previous_size->size_value);
 267         pci_write_config_dword(agp_bridge->dev, AMD_APSIZE, temp);
 268         iounmap((void __iomem *) amd_irongate_private.registers);
 269 }
 270 
 271 /*
 272  * This routine could be implemented by taking the addresses
 273  * written to the GATT, and flushing them individually.  However
 274  * currently it just flushes the whole table.  Which is probably
 275  * more efficient, since agp_memory blocks can be a large number of
 276  * entries.
 277  */
 278 
 279 static void amd_irongate_tlbflush(struct agp_memory *temp)
 280 {
 281         writel(1, amd_irongate_private.registers+AMD_TLBFLUSH);
 282         readl(amd_irongate_private.registers+AMD_TLBFLUSH);     /* PCI Posting. */
 283 }
 284 
 285 static int amd_insert_memory(struct agp_memory *mem, off_t pg_start, int type)
 286 {
 287         int i, j, num_entries;
 288         unsigned long __iomem *cur_gatt;
 289         unsigned long addr;
 290 
 291         num_entries = A_SIZE_LVL2(agp_bridge->current_size)->num_entries;
 292 
 293         if (type != mem->type ||
 294             agp_bridge->driver->agp_type_to_mask_type(agp_bridge, type))
 295                 return -EINVAL;
 296 
 297         if ((pg_start + mem->page_count) > num_entries)
 298                 return -EINVAL;
 299 
 300         j = pg_start;
 301         while (j < (pg_start + mem->page_count)) {
 302                 addr = (j * PAGE_SIZE) + agp_bridge->gart_bus_addr;
 303                 cur_gatt = GET_GATT(addr);
 304                 if (!PGE_EMPTY(agp_bridge, readl(cur_gatt+GET_GATT_OFF(addr))))
 305                         return -EBUSY;
 306                 j++;
 307         }
 308 
 309         if (!mem->is_flushed) {
 310                 global_cache_flush();
 311                 mem->is_flushed = true;
 312         }
 313 
 314         for (i = 0, j = pg_start; i < mem->page_count; i++, j++) {
 315                 addr = (j * PAGE_SIZE) + agp_bridge->gart_bus_addr;
 316                 cur_gatt = GET_GATT(addr);
 317                 writel(agp_generic_mask_memory(agp_bridge,
 318                                                page_to_phys(mem->pages[i]),
 319                                                mem->type),
 320                        cur_gatt+GET_GATT_OFF(addr));
 321                 readl(cur_gatt+GET_GATT_OFF(addr));     /* PCI Posting. */
 322         }
 323         amd_irongate_tlbflush(mem);
 324         return 0;
 325 }
 326 
 327 static int amd_remove_memory(struct agp_memory *mem, off_t pg_start, int type)
 328 {
 329         int i;
 330         unsigned long __iomem *cur_gatt;
 331         unsigned long addr;
 332 
 333         if (type != mem->type ||
 334             agp_bridge->driver->agp_type_to_mask_type(agp_bridge, type))
 335                 return -EINVAL;
 336 
 337         for (i = pg_start; i < (mem->page_count + pg_start); i++) {
 338                 addr = (i * PAGE_SIZE) + agp_bridge->gart_bus_addr;
 339                 cur_gatt = GET_GATT(addr);
 340                 writel(agp_bridge->scratch_page, cur_gatt+GET_GATT_OFF(addr));
 341                 readl(cur_gatt+GET_GATT_OFF(addr));     /* PCI Posting. */
 342         }
 343 
 344         amd_irongate_tlbflush(mem);
 345         return 0;
 346 }
 347 
 348 static const struct aper_size_info_lvl2 amd_irongate_sizes[7] =
 349 {
 350         {2048, 524288, 0x0000000c},
 351         {1024, 262144, 0x0000000a},
 352         {512, 131072, 0x00000008},
 353         {256, 65536, 0x00000006},
 354         {128, 32768, 0x00000004},
 355         {64, 16384, 0x00000002},
 356         {32, 8192, 0x00000000}
 357 };
 358 
 359 static const struct gatt_mask amd_irongate_masks[] =
 360 {
 361         {.mask = 1, .type = 0}
 362 };
 363 
 364 static const struct agp_bridge_driver amd_irongate_driver = {
 365         .owner                  = THIS_MODULE,
 366         .aperture_sizes         = amd_irongate_sizes,
 367         .size_type              = LVL2_APER_SIZE,
 368         .num_aperture_sizes     = 7,
 369         .needs_scratch_page     = true,
 370         .configure              = amd_irongate_configure,
 371         .fetch_size             = amd_irongate_fetch_size,
 372         .cleanup                = amd_irongate_cleanup,
 373         .tlb_flush              = amd_irongate_tlbflush,
 374         .mask_memory            = agp_generic_mask_memory,
 375         .masks                  = amd_irongate_masks,
 376         .agp_enable             = agp_generic_enable,
 377         .cache_flush            = global_cache_flush,
 378         .create_gatt_table      = amd_create_gatt_table,
 379         .free_gatt_table        = amd_free_gatt_table,
 380         .insert_memory          = amd_insert_memory,
 381         .remove_memory          = amd_remove_memory,
 382         .alloc_by_type          = agp_generic_alloc_by_type,
 383         .free_by_type           = agp_generic_free_by_type,
 384         .agp_alloc_page         = agp_generic_alloc_page,
 385         .agp_alloc_pages        = agp_generic_alloc_pages,
 386         .agp_destroy_page       = agp_generic_destroy_page,
 387         .agp_destroy_pages      = agp_generic_destroy_pages,
 388         .agp_type_to_mask_type  = agp_generic_type_to_mask_type,
 389 };
 390 
 391 static struct agp_device_ids amd_agp_device_ids[] =
 392 {
 393         {
 394                 .device_id      = PCI_DEVICE_ID_AMD_FE_GATE_7006,
 395                 .chipset_name   = "Irongate",
 396         },
 397         {
 398                 .device_id      = PCI_DEVICE_ID_AMD_FE_GATE_700E,
 399                 .chipset_name   = "761",
 400         },
 401         {
 402                 .device_id      = PCI_DEVICE_ID_AMD_FE_GATE_700C,
 403                 .chipset_name   = "760MP",
 404         },
 405         { }, /* dummy final entry, always present */
 406 };
 407 
 408 static int agp_amdk7_probe(struct pci_dev *pdev,
 409                            const struct pci_device_id *ent)
 410 {
 411         struct agp_bridge_data *bridge;
 412         u8 cap_ptr;
 413         int j;
 414 
 415         cap_ptr = pci_find_capability(pdev, PCI_CAP_ID_AGP);
 416         if (!cap_ptr)
 417                 return -ENODEV;
 418 
 419         j = ent - agp_amdk7_pci_table;
 420         dev_info(&pdev->dev, "AMD %s chipset\n",
 421                  amd_agp_device_ids[j].chipset_name);
 422 
 423         bridge = agp_alloc_bridge();
 424         if (!bridge)
 425                 return -ENOMEM;
 426 
 427         bridge->driver = &amd_irongate_driver;
 428         bridge->dev_private_data = &amd_irongate_private,
 429         bridge->dev = pdev;
 430         bridge->capndx = cap_ptr;
 431 
 432         /* 751 Errata (22564_B-1.PDF)
 433            erratum 20: strobe glitch with Nvidia NV10 GeForce cards.
 434            system controller may experience noise due to strong drive strengths
 435          */
 436         if (agp_bridge->dev->device == PCI_DEVICE_ID_AMD_FE_GATE_7006) {
 437                 struct pci_dev *gfxcard=NULL;
 438 
 439                 cap_ptr = 0;
 440                 while (!cap_ptr) {
 441                         gfxcard = pci_get_class(PCI_CLASS_DISPLAY_VGA<<8, gfxcard);
 442                         if (!gfxcard) {
 443                                 dev_info(&pdev->dev, "no AGP VGA controller\n");
 444                                 return -ENODEV;
 445                         }
 446                         cap_ptr = pci_find_capability(gfxcard, PCI_CAP_ID_AGP);
 447                 }
 448 
 449                 /* With so many variants of NVidia cards, it's simpler just
 450                    to blacklist them all, and then whitelist them as needed
 451                    (if necessary at all). */
 452                 if (gfxcard->vendor == PCI_VENDOR_ID_NVIDIA) {
 453                         agp_bridge->flags |= AGP_ERRATA_1X;
 454                         dev_info(&pdev->dev, "AMD 751 chipset with NVidia GeForce; forcing 1X due to errata\n");
 455                 }
 456                 pci_dev_put(gfxcard);
 457         }
 458 
 459         /* 761 Errata (23613_F.pdf)
 460          * Revisions B0/B1 were a disaster.
 461          * erratum 44: SYSCLK/AGPCLK skew causes 2X failures -- Force mode to 1X
 462          * erratum 45: Timing problem prevents fast writes -- Disable fast write.
 463          * erratum 46: Setup violation on AGP SBA pins - Disable side band addressing.
 464          * With this lot disabled, we should prevent lockups. */
 465         if (agp_bridge->dev->device == PCI_DEVICE_ID_AMD_FE_GATE_700E) {
 466                 if (pdev->revision == 0x10 || pdev->revision == 0x11) {
 467                         agp_bridge->flags = AGP_ERRATA_FASTWRITES;
 468                         agp_bridge->flags |= AGP_ERRATA_SBA;
 469                         agp_bridge->flags |= AGP_ERRATA_1X;
 470                         dev_info(&pdev->dev, "AMD 761 chipset with errata; disabling AGP fast writes & SBA and forcing to 1X\n");
 471                 }
 472         }
 473 
 474         /* Fill in the mode register */
 475         pci_read_config_dword(pdev,
 476                         bridge->capndx+PCI_AGP_STATUS,
 477                         &bridge->mode);
 478 
 479         pci_set_drvdata(pdev, bridge);
 480         return agp_add_bridge(bridge);
 481 }
 482 
 483 static void agp_amdk7_remove(struct pci_dev *pdev)
 484 {
 485         struct agp_bridge_data *bridge = pci_get_drvdata(pdev);
 486 
 487         agp_remove_bridge(bridge);
 488         agp_put_bridge(bridge);
 489 }
 490 
 491 #ifdef CONFIG_PM
 492 
 493 static int agp_amdk7_suspend(struct pci_dev *pdev, pm_message_t state)
 494 {
 495         pci_save_state(pdev);
 496         pci_set_power_state(pdev, pci_choose_state(pdev, state));
 497 
 498         return 0;
 499 }
 500 
 501 static int agp_amdk7_resume(struct pci_dev *pdev)
 502 {
 503         pci_set_power_state(pdev, PCI_D0);
 504         pci_restore_state(pdev);
 505 
 506         return amd_irongate_driver.configure();
 507 }
 508 
 509 #endif /* CONFIG_PM */
 510 
 511 /* must be the same order as name table above */
 512 static const struct pci_device_id agp_amdk7_pci_table[] = {
 513         {
 514         .class          = (PCI_CLASS_BRIDGE_HOST << 8),
 515         .class_mask     = ~0,
 516         .vendor         = PCI_VENDOR_ID_AMD,
 517         .device         = PCI_DEVICE_ID_AMD_FE_GATE_7006,
 518         .subvendor      = PCI_ANY_ID,
 519         .subdevice      = PCI_ANY_ID,
 520         },
 521         {
 522         .class          = (PCI_CLASS_BRIDGE_HOST << 8),
 523         .class_mask     = ~0,
 524         .vendor         = PCI_VENDOR_ID_AMD,
 525         .device         = PCI_DEVICE_ID_AMD_FE_GATE_700E,
 526         .subvendor      = PCI_ANY_ID,
 527         .subdevice      = PCI_ANY_ID,
 528         },
 529         {
 530         .class          = (PCI_CLASS_BRIDGE_HOST << 8),
 531         .class_mask     = ~0,
 532         .vendor         = PCI_VENDOR_ID_AMD,
 533         .device         = PCI_DEVICE_ID_AMD_FE_GATE_700C,
 534         .subvendor      = PCI_ANY_ID,
 535         .subdevice      = PCI_ANY_ID,
 536         },
 537         { }
 538 };
 539 
 540 MODULE_DEVICE_TABLE(pci, agp_amdk7_pci_table);
 541 
 542 static struct pci_driver agp_amdk7_pci_driver = {
 543         .name           = "agpgart-amdk7",
 544         .id_table       = agp_amdk7_pci_table,
 545         .probe          = agp_amdk7_probe,
 546         .remove         = agp_amdk7_remove,
 547 #ifdef CONFIG_PM
 548         .suspend        = agp_amdk7_suspend,
 549         .resume         = agp_amdk7_resume,
 550 #endif
 551 };
 552 
 553 static int __init agp_amdk7_init(void)
 554 {
 555         if (agp_off)
 556                 return -EINVAL;
 557         return pci_register_driver(&agp_amdk7_pci_driver);
 558 }
 559 
 560 static void __exit agp_amdk7_cleanup(void)
 561 {
 562         pci_unregister_driver(&agp_amdk7_pci_driver);
 563 }
 564 
 565 module_init(agp_amdk7_init);
 566 module_exit(agp_amdk7_cleanup);
 567 
 568 MODULE_LICENSE("GPL and additional rights");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/char/agp/amd-k7-agp.c

DEFINITIONS
