drivers/pci/msi.c

   1 /*
   2  * File:        msi.c
   3  * Purpose:     PCI Message Signaled Interrupt (MSI)
   4  *
   5  * Copyright (C) 2003-2004 Intel
   6  * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com)
   7  */
   8
   9 #include <linux/err.h>
  10 #include <linux/mm.h>
  11 #include <linux/irq.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/init.h>
  14 #include <linux/ioport.h>
  15 #include <linux/smp_lock.h>
  16 #include <linux/pci.h>
  17 #include <linux/proc_fs.h>
  18 #include <linux/msi.h>
  19
  20 #include <asm/errno.h>
  21 #include <asm/io.h>
  22 #include <asm/smp.h>
  23
  24 #include "pci.h"
  25 #include "msi.h"
  26
  27 static DEFINE_SPINLOCK(msi_lock);
  28 static struct msi_desc* msi_desc[NR_IRQS] = { [0 ... NR_IRQS-1] = NULL };
  29 static struct kmem_cache* msi_cachep;
  30
  31 static int pci_msi_enable = 1;
  32
  33 static int msi_cache_init(void)
  34 {
  35         msi_cachep = kmem_cache_create("msi_cache", sizeof(struct msi_desc),
  36                                         0, SLAB_HWCACHE_ALIGN, NULL, NULL);
  37         if (!msi_cachep)
  38                 return -ENOMEM;
  39
  40         return 0;
  41 }
  42
  43 static void msi_set_mask_bit(unsigned int irq, int flag)
  44 {
  45         struct msi_desc *entry;
  46
  47         entry = msi_desc[irq];
  48         BUG_ON(!entry || !entry->dev);
  49         switch (entry->msi_attrib.type) {
  50         case PCI_CAP_ID_MSI:
  51                 if (entry->msi_attrib.maskbit) {
  52                         int             pos;
  53                         u32             mask_bits;
  54
  55                         pos = (long)entry->mask_base;
  56                         pci_read_config_dword(entry->dev, pos, &mask_bits);
  57                         mask_bits &= ~(1);
  58                         mask_bits |= flag;
  59                         pci_write_config_dword(entry->dev, pos, mask_bits);
  60                 }
  61                 break;
  62         case PCI_CAP_ID_MSIX:
  63         {
  64                 int offset = entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
  65                         PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET;
  66                 writel(flag, entry->mask_base + offset);
  67                 break;
  68         }
  69         default:
  70                 BUG();
  71                 break;
  72         }
  73 }
  74
  75 void read_msi_msg(unsigned int irq, struct msi_msg *msg)
  76 {
  77         struct msi_desc *entry = get_irq_data(irq);
  78         switch(entry->msi_attrib.type) {
  79         case PCI_CAP_ID_MSI:
  80         {
  81                 struct pci_dev *dev = entry->dev;
  82                 int pos = entry->msi_attrib.pos;
  83                 u16 data;
  84
  85                 pci_read_config_dword(dev, msi_lower_address_reg(pos),
  86                                         &msg->address_lo);
  87                 if (entry->msi_attrib.is_64) {
  88                         pci_read_config_dword(dev, msi_upper_address_reg(pos),
  89                                                 &msg->address_hi);
  90                         pci_read_config_word(dev, msi_data_reg(pos, 1), &data);
  91                 } else {
  92                         msg->address_hi = 0;
  93                         pci_read_config_word(dev, msi_data_reg(pos, 1), &data);
  94                 }
  95                 msg->data = data;
  96                 break;
  97         }
  98         case PCI_CAP_ID_MSIX:
  99         {
 100                 void __iomem *base;
 101                 base = entry->mask_base +
 102                         entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
 103
 104                 msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
 105                 msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
 106                 msg->data = readl(base + PCI_MSIX_ENTRY_DATA_OFFSET);
 107                 break;
 108         }
 109         default:
 110                 BUG();
 111         }
 112 }
 113
 114 void write_msi_msg(unsigned int irq, struct msi_msg *msg)
 115 {
 116         struct msi_desc *entry = get_irq_data(irq);
 117         switch (entry->msi_attrib.type) {
 118         case PCI_CAP_ID_MSI:
 119         {
 120                 struct pci_dev *dev = entry->dev;
 121                 int pos = entry->msi_attrib.pos;
 122
 123                 pci_write_config_dword(dev, msi_lower_address_reg(pos),
 124                                         msg->address_lo);
 125                 if (entry->msi_attrib.is_64) {
 126                         pci_write_config_dword(dev, msi_upper_address_reg(pos),
 127                                                 msg->address_hi);
 128                         pci_write_config_word(dev, msi_data_reg(pos, 1),
 129                                                 msg->data);
 130                 } else {
 131                         pci_write_config_word(dev, msi_data_reg(pos, 0),
 132                                                 msg->data);
 133                 }
 134                 break;
 135         }
 136         case PCI_CAP_ID_MSIX:
 137         {
 138                 void __iomem *base;
 139                 base = entry->mask_base +
 140                         entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
 141
 142                 writel(msg->address_lo,
 143                         base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
 144                 writel(msg->address_hi,
 145                         base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
 146                 writel(msg->data, base + PCI_MSIX_ENTRY_DATA_OFFSET);
 147                 break;
 148         }
 149         default:
 150                 BUG();
 151         }
 152 }
 153
 154 void mask_msi_irq(unsigned int irq)
 155 {
 156         msi_set_mask_bit(irq, 1);
 157 }
 158
 159 void unmask_msi_irq(unsigned int irq)
 160 {
 161         msi_set_mask_bit(irq, 0);
 162 }
 163
 164 static int msi_free_irq(struct pci_dev* dev, int irq);
 165 static int msi_init(void)
 166 {
 167         static int status = -ENOMEM;
 168
 169         if (!status)
 170                 return status;
 171
 172         if (pci_msi_quirk) {
 173                 pci_msi_enable = 0;
 174                 printk(KERN_WARNING "PCI: MSI quirk detected. MSI disabled.\n");
 175                 status = -EINVAL;
 176                 return status;
 177         }
 178
 179         status = msi_cache_init();
 180         if (status < 0) {
 181                 pci_msi_enable = 0;
 182                 printk(KERN_WARNING "PCI: MSI cache init failed\n");
 183                 return status;
 184         }
 185
 186         return status;
 187 }
 188
 189 static struct msi_desc* alloc_msi_entry(void)
 190 {
 191         struct msi_desc *entry;
 192
 193         entry = kmem_cache_zalloc(msi_cachep, GFP_KERNEL);
 194         if (!entry)
 195                 return NULL;
 196
 197         entry->link.tail = entry->link.head = 0;        /* single message */
 198         entry->dev = NULL;
 199
 200         return entry;
 201 }
 202
 203 static void attach_msi_entry(struct msi_desc *entry, int irq)
 204 {
 205         unsigned long flags;
 206
 207         spin_lock_irqsave(&msi_lock, flags);
 208         msi_desc[irq] = entry;
 209         spin_unlock_irqrestore(&msi_lock, flags);
 210 }
 211
 212 static int create_msi_irq(void)
 213 {
 214         struct msi_desc *entry;
 215         int irq;
 216
 217         entry = alloc_msi_entry();
 218         if (!entry)
 219                 return -ENOMEM;
 220
 221         irq = create_irq();
 222         if (irq < 0) {
 223                 kmem_cache_free(msi_cachep, entry);
 224                 return -EBUSY;
 225         }
 226
 227         set_irq_data(irq, entry);
 228
 229         return irq;
 230 }
 231
 232 static void destroy_msi_irq(unsigned int irq)
 233 {
 234         struct msi_desc *entry;
 235
 236         entry = get_irq_data(irq);
 237         set_irq_chip(irq, NULL);
 238         set_irq_data(irq, NULL);
 239         destroy_irq(irq);
 240         kmem_cache_free(msi_cachep, entry);
 241 }
 242
 243 static void enable_msi_mode(struct pci_dev *dev, int pos, int type)
 244 {
 245         u16 control;
 246
 247         pci_read_config_word(dev, msi_control_reg(pos), &control);
 248         if (type == PCI_CAP_ID_MSI) {
 249                 /* Set enabled bits to single MSI & enable MSI_enable bit */
 250                 msi_enable(control, 1);
 251                 pci_write_config_word(dev, msi_control_reg(pos), control);
 252                 dev->msi_enabled = 1;
 253         } else {
 254                 msix_enable(control);
 255                 pci_write_config_word(dev, msi_control_reg(pos), control);
 256                 dev->msix_enabled = 1;
 257         }
 258         if (pci_find_capability(dev, PCI_CAP_ID_EXP)) {
 259                 /* PCI Express Endpoint device detected */
 260                 pci_intx(dev, 0);  /* disable intx */
 261         }
 262 }
 263
 264 void disable_msi_mode(struct pci_dev *dev, int pos, int type)
 265 {
 266         u16 control;
 267
 268         pci_read_config_word(dev, msi_control_reg(pos), &control);
 269         if (type == PCI_CAP_ID_MSI) {
 270                 /* Set enabled bits to single MSI & enable MSI_enable bit */
 271                 msi_disable(control);
 272                 pci_write_config_word(dev, msi_control_reg(pos), control);
 273                 dev->msi_enabled = 0;
 274         } else {
 275                 msix_disable(control);
 276                 pci_write_config_word(dev, msi_control_reg(pos), control);
 277                 dev->msix_enabled = 0;
 278         }
 279         if (pci_find_capability(dev, PCI_CAP_ID_EXP)) {
 280                 /* PCI Express Endpoint device detected */
 281                 pci_intx(dev, 1);  /* enable intx */
 282         }
 283 }
 284
 285 static int msi_lookup_irq(struct pci_dev *dev, int type)
 286 {
 287         int irq;
 288         unsigned long flags;
 289
 290         spin_lock_irqsave(&msi_lock, flags);
 291         for (irq = 0; irq < NR_IRQS; irq++) {
 292                 if (!msi_desc[irq] || msi_desc[irq]->dev != dev ||
 293                         msi_desc[irq]->msi_attrib.type != type ||
 294                         msi_desc[irq]->msi_attrib.default_irq != dev->irq)
 295                         continue;
 296                 spin_unlock_irqrestore(&msi_lock, flags);
 297                 /* This pre-assigned MSI irq for this device
 298                    already exits. Override dev->irq with this irq */
 299                 dev->irq = irq;
 300                 return 0;
 301         }
 302         spin_unlock_irqrestore(&msi_lock, flags);
 303
 304         return -EACCES;
 305 }
 306
 307 void pci_scan_msi_device(struct pci_dev *dev)
 308 {
 309         if (!dev)
 310                 return;
 311 }
 312
 313 #ifdef CONFIG_PM
 314 int pci_save_msi_state(struct pci_dev *dev)
 315 {
 316         int pos, i = 0;
 317         u16 control;
 318         struct pci_cap_saved_state *save_state;
 319         u32 *cap;
 320
 321         pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
 322         if (pos <= 0 || dev->no_msi)
 323                 return 0;
 324
 325         pci_read_config_word(dev, msi_control_reg(pos), &control);
 326         if (!(control & PCI_MSI_FLAGS_ENABLE))
 327                 return 0;
 328
 329         save_state = kzalloc(sizeof(struct pci_cap_saved_state) + sizeof(u32) * 5,
 330                 GFP_KERNEL);
 331         if (!save_state) {
 332                 printk(KERN_ERR "Out of memory in pci_save_msi_state\n");
 333                 return -ENOMEM;
 334         }
 335         cap = &save_state->data[0];
 336
 337         pci_read_config_dword(dev, pos, &cap[i++]);
 338         control = cap[0] >> 16;
 339         pci_read_config_dword(dev, pos + PCI_MSI_ADDRESS_LO, &cap[i++]);
 340         if (control & PCI_MSI_FLAGS_64BIT) {
 341                 pci_read_config_dword(dev, pos + PCI_MSI_ADDRESS_HI, &cap[i++]);
 342                 pci_read_config_dword(dev, pos + PCI_MSI_DATA_64, &cap[i++]);
 343         } else
 344                 pci_read_config_dword(dev, pos + PCI_MSI_DATA_32, &cap[i++]);
 345         if (control & PCI_MSI_FLAGS_MASKBIT)
 346                 pci_read_config_dword(dev, pos + PCI_MSI_MASK_BIT, &cap[i++]);
 347         save_state->cap_nr = PCI_CAP_ID_MSI;
 348         pci_add_saved_cap(dev, save_state);
 349         return 0;
 350 }
 351
 352 void pci_restore_msi_state(struct pci_dev *dev)
 353 {
 354         int i = 0, pos;
 355         u16 control;
 356         struct pci_cap_saved_state *save_state;
 357         u32 *cap;
 358
 359         save_state = pci_find_saved_cap(dev, PCI_CAP_ID_MSI);
 360         pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
 361         if (!save_state || pos <= 0)
 362                 return;
 363         cap = &save_state->data[0];
 364
 365         control = cap[i++] >> 16;
 366         pci_write_config_dword(dev, pos + PCI_MSI_ADDRESS_LO, cap[i++]);
 367         if (control & PCI_MSI_FLAGS_64BIT) {
 368                 pci_write_config_dword(dev, pos + PCI_MSI_ADDRESS_HI, cap[i++]);
 369                 pci_write_config_dword(dev, pos + PCI_MSI_DATA_64, cap[i++]);
 370         } else
 371                 pci_write_config_dword(dev, pos + PCI_MSI_DATA_32, cap[i++]);
 372         if (control & PCI_MSI_FLAGS_MASKBIT)
 373                 pci_write_config_dword(dev, pos + PCI_MSI_MASK_BIT, cap[i++]);
 374         pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
 375         enable_msi_mode(dev, pos, PCI_CAP_ID_MSI);
 376         pci_remove_saved_cap(save_state);
 377         kfree(save_state);
 378 }
 379
 380 int pci_save_msix_state(struct pci_dev *dev)
 381 {
 382         int pos;
 383         int temp;
 384         int irq, head, tail = 0;
 385         u16 control;
 386         struct pci_cap_saved_state *save_state;
 387
 388         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
 389         if (pos <= 0 || dev->no_msi)
 390                 return 0;
 391
 392         /* save the capability */
 393         pci_read_config_word(dev, msi_control_reg(pos), &control);
 394         if (!(control & PCI_MSIX_FLAGS_ENABLE))
 395                 return 0;
 396         save_state = kzalloc(sizeof(struct pci_cap_saved_state) + sizeof(u16),
 397                 GFP_KERNEL);
 398         if (!save_state) {
 399                 printk(KERN_ERR "Out of memory in pci_save_msix_state\n");
 400                 return -ENOMEM;
 401         }
 402         *((u16 *)&save_state->data[0]) = control;
 403
 404         /* save the table */
 405         temp = dev->irq;
 406         if (msi_lookup_irq(dev, PCI_CAP_ID_MSIX)) {
 407                 kfree(save_state);
 408                 return -EINVAL;
 409         }
 410
 411         irq = head = dev->irq;
 412         while (head != tail) {
 413                 struct msi_desc *entry;
 414
 415                 entry = msi_desc[irq];
 416                 read_msi_msg(irq, &entry->msg_save);
 417
 418                 tail = msi_desc[irq]->link.tail;
 419                 irq = tail;
 420         }
 421         dev->irq = temp;
 422
 423         save_state->cap_nr = PCI_CAP_ID_MSIX;
 424         pci_add_saved_cap(dev, save_state);
 425         return 0;
 426 }
 427
 428 void pci_restore_msix_state(struct pci_dev *dev)
 429 {
 430         u16 save;
 431         int pos;
 432         int irq, head, tail = 0;
 433         struct msi_desc *entry;
 434         int temp;
 435         struct pci_cap_saved_state *save_state;
 436
 437         save_state = pci_find_saved_cap(dev, PCI_CAP_ID_MSIX);
 438         if (!save_state)
 439                 return;
 440         save = *((u16 *)&save_state->data[0]);
 441         pci_remove_saved_cap(save_state);
 442         kfree(save_state);
 443
 444         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
 445         if (pos <= 0)
 446                 return;
 447
 448         /* route the table */
 449         temp = dev->irq;
 450         if (msi_lookup_irq(dev, PCI_CAP_ID_MSIX))
 451                 return;
 452         irq = head = dev->irq;
 453         while (head != tail) {
 454                 entry = msi_desc[irq];
 455                 write_msi_msg(irq, &entry->msg_save);
 456
 457                 tail = msi_desc[irq]->link.tail;
 458                 irq = tail;
 459         }
 460         dev->irq = temp;
 461
 462         pci_write_config_word(dev, msi_control_reg(pos), save);
 463         enable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
 464 }
 465 #endif
 466
 467 /**
 468  * msi_capability_init - configure device's MSI capability structure
 469  * @dev: pointer to the pci_dev data structure of MSI device function
 470  *
 471  * Setup the MSI capability structure of device function with a single
 472  * MSI irq, regardless of device function is capable of handling
 473  * multiple messages. A return of zero indicates the successful setup
 474  * of an entry zero with the new MSI irq or non-zero for otherwise.
 475  **/
 476 static int msi_capability_init(struct pci_dev *dev)
 477 {
 478         int status;
 479         struct msi_desc *entry;
 480         int pos, irq;
 481         u16 control;
 482
 483         pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
 484         pci_read_config_word(dev, msi_control_reg(pos), &control);
 485         /* MSI Entry Initialization */
 486         irq = create_msi_irq();
 487         if (irq < 0)
 488                 return irq;
 489
 490         entry = get_irq_data(irq);
 491         entry->link.head = irq;
 492         entry->link.tail = irq;
 493         entry->msi_attrib.type = PCI_CAP_ID_MSI;
 494         entry->msi_attrib.is_64 = is_64bit_address(control);
 495         entry->msi_attrib.entry_nr = 0;
 496         entry->msi_attrib.maskbit = is_mask_bit_support(control);
 497         entry->msi_attrib.default_irq = dev->irq;       /* Save IOAPIC IRQ */
 498         entry->msi_attrib.pos = pos;
 499         if (is_mask_bit_support(control)) {
 500                 entry->mask_base = (void __iomem *)(long)msi_mask_bits_reg(pos,
 501                                 is_64bit_address(control));
 502         }
 503         entry->dev = dev;
 504         if (entry->msi_attrib.maskbit) {
 505                 unsigned int maskbits, temp;
 506                 /* All MSIs are unmasked by default, Mask them all */
 507                 pci_read_config_dword(dev,
 508                         msi_mask_bits_reg(pos, is_64bit_address(control)),
 509                         &maskbits);
 510                 temp = (1 << multi_msi_capable(control));
 511                 temp = ((temp - 1) & ~temp);
 512                 maskbits |= temp;
 513                 pci_write_config_dword(dev,
 514                         msi_mask_bits_reg(pos, is_64bit_address(control)),
 515                         maskbits);
 516         }
 517         /* Configure MSI capability structure */
 518         status = arch_setup_msi_irq(irq, dev);
 519         if (status < 0) {
 520                 destroy_msi_irq(irq);
 521                 return status;
 522         }
 523
 524         attach_msi_entry(entry, irq);
 525         /* Set MSI enabled bits  */
 526         enable_msi_mode(dev, pos, PCI_CAP_ID_MSI);
 527
 528         dev->irq = irq;
 529         return 0;
 530 }
 531
 532 /**
 533  * msix_capability_init - configure device's MSI-X capability
 534  * @dev: pointer to the pci_dev data structure of MSI-X device function
 535  * @entries: pointer to an array of struct msix_entry entries
 536  * @nvec: number of @entries
 537  *
 538  * Setup the MSI-X capability structure of device function with a
 539  * single MSI-X irq. A return of zero indicates the successful setup of
 540  * requested MSI-X entries with allocated irqs or non-zero for otherwise.
 541  **/
 542 static int msix_capability_init(struct pci_dev *dev,
 543                                 struct msix_entry *entries, int nvec)
 544 {
 545         struct msi_desc *head = NULL, *tail = NULL, *entry = NULL;
 546         int status;
 547         int irq, pos, i, j, nr_entries, temp = 0;
 548         unsigned long phys_addr;
 549         u32 table_offset;
 550         u16 control;
 551         u8 bir;
 552         void __iomem *base;
 553
 554         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
 555         /* Request & Map MSI-X table region */
 556         pci_read_config_word(dev, msi_control_reg(pos), &control);
 557         nr_entries = multi_msix_capable(control);
 558
 559         pci_read_config_dword(dev, msix_table_offset_reg(pos), &table_offset);
 560         bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
 561         table_offset &= ~PCI_MSIX_FLAGS_BIRMASK;
 562         phys_addr = pci_resource_start (dev, bir) + table_offset;
 563         base = ioremap_nocache(phys_addr, nr_entries * PCI_MSIX_ENTRY_SIZE);
 564         if (base == NULL)
 565                 return -ENOMEM;
 566
 567         /* MSI-X Table Initialization */
 568         for (i = 0; i < nvec; i++) {
 569                 irq = create_msi_irq();
 570                 if (irq < 0)
 571                         break;
 572
 573                 entry = get_irq_data(irq);
 574                 j = entries[i].entry;
 575                 entries[i].vector = irq;
 576                 entry->msi_attrib.type = PCI_CAP_ID_MSIX;
 577                 entry->msi_attrib.is_64 = 1;
 578                 entry->msi_attrib.entry_nr = j;
 579                 entry->msi_attrib.maskbit = 1;
 580                 entry->msi_attrib.default_irq = dev->irq;
 581                 entry->msi_attrib.pos = pos;
 582                 entry->dev = dev;
 583                 entry->mask_base = base;
 584                 if (!head) {
 585                         entry->link.head = irq;
 586                         entry->link.tail = irq;
 587                         head = entry;
 588                 } else {
 589                         entry->link.head = temp;
 590                         entry->link.tail = tail->link.tail;
 591                         tail->link.tail = irq;
 592                         head->link.head = irq;
 593                 }
 594                 temp = irq;
 595                 tail = entry;
 596                 /* Configure MSI-X capability structure */
 597                 status = arch_setup_msi_irq(irq, dev);
 598                 if (status < 0) {
 599                         destroy_msi_irq(irq);
 600                         break;
 601                 }
 602
 603                 attach_msi_entry(entry, irq);
 604         }
 605         if (i != nvec) {
 606                 int avail = i - 1;
 607                 i--;
 608                 for (; i >= 0; i--) {
 609                         irq = (entries + i)->vector;
 610                         msi_free_irq(dev, irq);
 611                         (entries + i)->vector = 0;
 612                 }
 613                 /* If we had some success report the number of irqs
 614                  * we succeeded in setting up.
 615                  */
 616                 if (avail <= 0)
 617                         avail = -EBUSY;
 618                 return avail;
 619         }
 620         /* Set MSI-X enabled bits */
 621         enable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
 622
 623         return 0;
 624 }
 625
 626 /**
 627  * pci_msi_supported - check whether MSI may be enabled on device
 628  * @dev: pointer to the pci_dev data structure of MSI device function
 629  *
 630  * Look at global flags, the device itself, and its parent busses
 631  * to return 0 if MSI are supported for the device.
 632  **/
 633 static
 634 int pci_msi_supported(struct pci_dev * dev)
 635 {
 636         struct pci_bus *bus;
 637
 638         /* MSI must be globally enabled and supported by the device */
 639         if (!pci_msi_enable || !dev || dev->no_msi)
 640                 return -EINVAL;
 641
 642         /* Any bridge which does NOT route MSI transactions from it's
 643          * secondary bus to it's primary bus must set NO_MSI flag on
 644          * the secondary pci_bus.
 645          * We expect only arch-specific PCI host bus controller driver
 646          * or quirks for specific PCI bridges to be setting NO_MSI.
 647          */
 648         for (bus = dev->bus; bus; bus = bus->parent)
 649                 if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
 650                         return -EINVAL;
 651
 652         return 0;
 653 }
 654
 655 /**
 656  * pci_enable_msi - configure device's MSI capability structure
 657  * @dev: pointer to the pci_dev data structure of MSI device function
 658  *
 659  * Setup the MSI capability structure of device function with
 660  * a single MSI irq upon its software driver call to request for
 661  * MSI mode enabled on its hardware device function. A return of zero
 662  * indicates the successful setup of an entry zero with the new MSI
 663  * irq or non-zero for otherwise.
 664  **/
 665 int pci_enable_msi(struct pci_dev* dev)
 666 {
 667         int pos, temp, status;
 668
 669         if (pci_msi_supported(dev) < 0)
 670                 return -EINVAL;
 671
 672         temp = dev->irq;
 673
 674         status = msi_init();
 675         if (status < 0)
 676                 return status;
 677
 678         pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
 679         if (!pos)
 680                 return -EINVAL;
 681
 682         WARN_ON(!msi_lookup_irq(dev, PCI_CAP_ID_MSI));
 683
 684         /* Check whether driver already requested for MSI-X irqs */
 685         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
 686         if (pos > 0 && !msi_lookup_irq(dev, PCI_CAP_ID_MSIX)) {
 687                         printk(KERN_INFO "PCI: %s: Can't enable MSI.  "
 688                                "Device already has MSI-X irq assigned\n",
 689                                pci_name(dev));
 690                         dev->irq = temp;
 691                         return -EINVAL;
 692         }
 693         status = msi_capability_init(dev);
 694         return status;
 695 }
 696
 697 void pci_disable_msi(struct pci_dev* dev)
 698 {
 699         struct msi_desc *entry;
 700         int pos, default_irq;
 701         u16 control;
 702         unsigned long flags;
 703
 704         if (!pci_msi_enable)
 705                 return;
 706         if (!dev)
 707                 return;
 708
 709         pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
 710         if (!pos)
 711                 return;
 712
 713         pci_read_config_word(dev, msi_control_reg(pos), &control);
 714         if (!(control & PCI_MSI_FLAGS_ENABLE))
 715                 return;
 716
 717         disable_msi_mode(dev, pos, PCI_CAP_ID_MSI);
 718
 719         spin_lock_irqsave(&msi_lock, flags);
 720         entry = msi_desc[dev->irq];
 721         if (!entry || !entry->dev || entry->msi_attrib.type != PCI_CAP_ID_MSI) {
 722                 spin_unlock_irqrestore(&msi_lock, flags);
 723                 return;
 724         }
 725         if (irq_has_action(dev->irq)) {
 726                 spin_unlock_irqrestore(&msi_lock, flags);
 727                 printk(KERN_WARNING "PCI: %s: pci_disable_msi() called without "
 728                        "free_irq() on MSI irq %d\n",
 729                        pci_name(dev), dev->irq);
 730                 BUG_ON(irq_has_action(dev->irq));
 731         } else {
 732                 default_irq = entry->msi_attrib.default_irq;
 733                 spin_unlock_irqrestore(&msi_lock, flags);
 734                 msi_free_irq(dev, dev->irq);
 735
 736                 /* Restore dev->irq to its default pin-assertion irq */
 737                 dev->irq = default_irq;
 738         }
 739 }
 740
 741 static int msi_free_irq(struct pci_dev* dev, int irq)
 742 {
 743         struct msi_desc *entry;
 744         int head, entry_nr, type;
 745         void __iomem *base;
 746         unsigned long flags;
 747
 748         arch_teardown_msi_irq(irq);
 749
 750         spin_lock_irqsave(&msi_lock, flags);
 751         entry = msi_desc[irq];
 752         if (!entry || entry->dev != dev) {
 753                 spin_unlock_irqrestore(&msi_lock, flags);
 754                 return -EINVAL;
 755         }
 756         type = entry->msi_attrib.type;
 757         entry_nr = entry->msi_attrib.entry_nr;
 758         head = entry->link.head;
 759         base = entry->mask_base;
 760         msi_desc[entry->link.head]->link.tail = entry->link.tail;
 761         msi_desc[entry->link.tail]->link.head = entry->link.head;
 762         entry->dev = NULL;
 763         msi_desc[irq] = NULL;
 764         spin_unlock_irqrestore(&msi_lock, flags);
 765
 766         destroy_msi_irq(irq);
 767
 768         if (type == PCI_CAP_ID_MSIX) {
 769                 writel(1, base + entry_nr * PCI_MSIX_ENTRY_SIZE +
 770                         PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
 771
 772                 if (head == irq)
 773                         iounmap(base);
 774         }
 775
 776         return 0;
 777 }
 778
 779 /**
 780  * pci_enable_msix - configure device's MSI-X capability structure
 781  * @dev: pointer to the pci_dev data structure of MSI-X device function
 782  * @entries: pointer to an array of MSI-X entries
 783  * @nvec: number of MSI-X irqs requested for allocation by device driver
 784  *
 785  * Setup the MSI-X capability structure of device function with the number
 786  * of requested irqs upon its software driver call to request for
 787  * MSI-X mode enabled on its hardware device function. A return of zero
 788  * indicates the successful configuration of MSI-X capability structure
 789  * with new allocated MSI-X irqs. A return of < 0 indicates a failure.
 790  * Or a return of > 0 indicates that driver request is exceeding the number
 791  * of irqs available. Driver should use the returned value to re-send
 792  * its request.
 793  **/
 794 int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
 795 {
 796         int status, pos, nr_entries;
 797         int i, j, temp;
 798         u16 control;
 799
 800         if (!entries || pci_msi_supported(dev) < 0)
 801                 return -EINVAL;
 802
 803         status = msi_init();
 804         if (status < 0)
 805                 return status;
 806
 807         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
 808         if (!pos)
 809                 return -EINVAL;
 810
 811         pci_read_config_word(dev, msi_control_reg(pos), &control);
 812         nr_entries = multi_msix_capable(control);
 813         if (nvec > nr_entries)
 814                 return -EINVAL;
 815
 816         /* Check for any invalid entries */
 817         for (i = 0; i < nvec; i++) {
 818                 if (entries[i].entry >= nr_entries)
 819                         return -EINVAL;         /* invalid entry */
 820                 for (j = i + 1; j < nvec; j++) {
 821                         if (entries[i].entry == entries[j].entry)
 822                                 return -EINVAL; /* duplicate entry */
 823                 }
 824         }
 825         temp = dev->irq;
 826         WARN_ON(!msi_lookup_irq(dev, PCI_CAP_ID_MSIX));
 827
 828         /* Check whether driver already requested for MSI irq */
 829         if (pci_find_capability(dev, PCI_CAP_ID_MSI) > 0 &&
 830                 !msi_lookup_irq(dev, PCI_CAP_ID_MSI)) {
 831                 printk(KERN_INFO "PCI: %s: Can't enable MSI-X.  "
 832                        "Device already has an MSI irq assigned\n",
 833                        pci_name(dev));
 834                 dev->irq = temp;
 835                 return -EINVAL;
 836         }
 837         status = msix_capability_init(dev, entries, nvec);
 838         return status;
 839 }
 840
 841 void pci_disable_msix(struct pci_dev* dev)
 842 {
 843         int pos, temp;
 844         u16 control;
 845
 846         if (!pci_msi_enable)
 847                 return;
 848         if (!dev)
 849                 return;
 850
 851         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
 852         if (!pos)
 853                 return;
 854
 855         pci_read_config_word(dev, msi_control_reg(pos), &control);
 856         if (!(control & PCI_MSIX_FLAGS_ENABLE))
 857                 return;
 858
 859         disable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
 860
 861         temp = dev->irq;
 862         if (!msi_lookup_irq(dev, PCI_CAP_ID_MSIX)) {
 863                 int irq, head, tail = 0, warning = 0;
 864                 unsigned long flags;
 865
 866                 irq = head = dev->irq;
 867                 dev->irq = temp;                        /* Restore pin IRQ */
 868                 while (head != tail) {
 869                         spin_lock_irqsave(&msi_lock, flags);
 870                         tail = msi_desc[irq]->link.tail;
 871                         spin_unlock_irqrestore(&msi_lock, flags);
 872                         if (irq_has_action(irq))
 873                                 warning = 1;
 874                         else if (irq != head)   /* Release MSI-X irq */
 875                                 msi_free_irq(dev, irq);
 876                         irq = tail;
 877                 }
 878                 msi_free_irq(dev, irq);
 879                 if (warning) {
 880                         printk(KERN_WARNING "PCI: %s: pci_disable_msix() called without "
 881                                "free_irq() on all MSI-X irqs\n",
 882                                pci_name(dev));
 883                         BUG_ON(warning > 0);
 884                 }
 885         }
 886 }
 887
 888 /**
 889  * msi_remove_pci_irq_vectors - reclaim MSI(X) irqs to unused state
 890  * @dev: pointer to the pci_dev data structure of MSI(X) device function
 891  *
 892  * Being called during hotplug remove, from which the device function
 893  * is hot-removed. All previous assigned MSI/MSI-X irqs, if
 894  * allocated for this device function, are reclaimed to unused state,
 895  * which may be used later on.
 896  **/
 897 void msi_remove_pci_irq_vectors(struct pci_dev* dev)
 898 {
 899         int pos, temp;
 900         unsigned long flags;
 901
 902         if (!pci_msi_enable || !dev)
 903                 return;
 904
 905         temp = dev->irq;                /* Save IOAPIC IRQ */
 906         pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
 907         if (pos > 0 && !msi_lookup_irq(dev, PCI_CAP_ID_MSI)) {
 908                 if (irq_has_action(dev->irq)) {
 909                         printk(KERN_WARNING "PCI: %s: msi_remove_pci_irq_vectors() "
 910                                "called without free_irq() on MSI irq %d\n",
 911                                pci_name(dev), dev->irq);
 912                         BUG_ON(irq_has_action(dev->irq));
 913                 } else /* Release MSI irq assigned to this device */
 914                         msi_free_irq(dev, dev->irq);
 915                 dev->irq = temp;                /* Restore IOAPIC IRQ */
 916         }
 917         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
 918         if (pos > 0 && !msi_lookup_irq(dev, PCI_CAP_ID_MSIX)) {
 919                 int irq, head, tail = 0, warning = 0;
 920                 void __iomem *base = NULL;
 921
 922                 irq = head = dev->irq;
 923                 while (head != tail) {
 924                         spin_lock_irqsave(&msi_lock, flags);
 925                         tail = msi_desc[irq]->link.tail;
 926                         base = msi_desc[irq]->mask_base;
 927                         spin_unlock_irqrestore(&msi_lock, flags);
 928                         if (irq_has_action(irq))
 929                                 warning = 1;
 930                         else if (irq != head) /* Release MSI-X irq */
 931                                 msi_free_irq(dev, irq);
 932                         irq = tail;
 933                 }
 934                 msi_free_irq(dev, irq);
 935                 if (warning) {
 936                         iounmap(base);
 937                         printk(KERN_WARNING "PCI: %s: msi_remove_pci_irq_vectors() "
 938                                "called without free_irq() on all MSI-X irqs\n",
 939                                pci_name(dev));
 940                         BUG_ON(warning > 0);
 941                 }
 942                 dev->irq = temp;                /* Restore IOAPIC IRQ */
 943         }
 944 }
 945
 946 void pci_no_msi(void)
 947 {
 948         pci_msi_enable = 0;
 949 }
 950
 951 EXPORT_SYMBOL(pci_enable_msi);
 952 EXPORT_SYMBOL(pci_disable_msi);
 953 EXPORT_SYMBOL(pci_enable_msix);
 954 EXPORT_SYMBOL(pci_disable_msix);