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/pci.h>
  16 #include <linux/proc_fs.h>
  17 #include <linux/msi.h>
  18 #include <linux/smp.h>
  19
  20 #include <asm/errno.h>
  21 #include <asm/io.h>
  22
  23 #include "pci.h"
  24 #include "msi.h"
  25
  26 static int pci_msi_enable = 1;
  27
  28 /* Arch hooks */
  29
  30 #ifndef arch_msi_check_device
  31 int arch_msi_check_device(struct pci_dev *dev, int nvec, int type)
  32 {
  33         return 0;
  34 }
  35 #endif
  36
  37 #ifndef arch_setup_msi_irqs
  38 int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
  39 {
  40         struct msi_desc *entry;
  41         int ret;
  42
  43         /*
  44          * If an architecture wants to support multiple MSI, it needs to
  45          * override arch_setup_msi_irqs()
  46          */
  47         if (type == PCI_CAP_ID_MSI && nvec > 1)
  48                 return 1;
  49
  50         list_for_each_entry(entry, &dev->msi_list, list) {
  51                 ret = arch_setup_msi_irq(dev, entry);
  52                 if (ret < 0)
  53                         return ret;
  54                 if (ret > 0)
  55                         return -ENOSPC;
  56         }
  57
  58         return 0;
  59 }
  60 #endif
  61
  62 #ifndef arch_teardown_msi_irqs
  63 void arch_teardown_msi_irqs(struct pci_dev *dev)
  64 {
  65         struct msi_desc *entry;
  66
  67         list_for_each_entry(entry, &dev->msi_list, list) {
  68                 int i, nvec;
  69                 if (entry->irq == 0)
  70                         continue;
  71                 nvec = 1 << entry->msi_attrib.multiple;
  72                 for (i = 0; i < nvec; i++)
  73                         arch_teardown_msi_irq(entry->irq + i);
  74         }
  75 }
  76 #endif
  77
  78 static void __msi_set_enable(struct pci_dev *dev, int pos, int enable)
  79 {
  80         u16 control;
  81
  82         if (pos) {
  83                 pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
  84                 control &= ~PCI_MSI_FLAGS_ENABLE;
  85                 if (enable)
  86                         control |= PCI_MSI_FLAGS_ENABLE;
  87                 pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
  88         }
  89 }
  90
  91 static void msi_set_enable(struct pci_dev *dev, int enable)
  92 {
  93         __msi_set_enable(dev, pci_find_capability(dev, PCI_CAP_ID_MSI), enable);
  94 }
  95
  96 static void msix_set_enable(struct pci_dev *dev, int enable)
  97 {
  98         int pos;
  99         u16 control;
 100
 101         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
 102         if (pos) {
 103                 pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
 104                 control &= ~PCI_MSIX_FLAGS_ENABLE;
 105                 if (enable)
 106                         control |= PCI_MSIX_FLAGS_ENABLE;
 107                 pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
 108         }
 109 }
 110
 111 static inline __attribute_const__ u32 msi_mask(unsigned x)
 112 {
 113         /* Don't shift by >= width of type */
 114         if (x >= 5)
 115                 return 0xffffffff;
 116         return (1 << (1 << x)) - 1;
 117 }
 118
 119 static inline __attribute_const__ u32 msi_capable_mask(u16 control)
 120 {
 121         return msi_mask((control >> 1) & 7);
 122 }
 123
 124 static inline __attribute_const__ u32 msi_enabled_mask(u16 control)
 125 {
 126         return msi_mask((control >> 4) & 7);
 127 }
 128
 129 /*
 130  * PCI 2.3 does not specify mask bits for each MSI interrupt.  Attempting to
 131  * mask all MSI interrupts by clearing the MSI enable bit does not work
 132  * reliably as devices without an INTx disable bit will then generate a
 133  * level IRQ which will never be cleared.
 134  *
 135  * Returns 1 if it succeeded in masking the interrupt and 0 if the device
 136  * doesn't support MSI masking.
 137  */
 138 static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
 139 {
 140         u32 mask_bits = desc->masked;
 141
 142         if (!desc->msi_attrib.maskbit)
 143                 return;
 144
 145         mask_bits &= ~mask;
 146         mask_bits |= flag;
 147         pci_write_config_dword(desc->dev, desc->mask_pos, mask_bits);
 148         desc->masked = mask_bits;
 149 }
 150
 151 /*
 152  * This internal function does not flush PCI writes to the device.
 153  * All users must ensure that they read from the device before either
 154  * assuming that the device state is up to date, or returning out of this
 155  * file.  This saves a few milliseconds when initialising devices with lots
 156  * of MSI-X interrupts.
 157  */
 158 static void msix_mask_irq(struct msi_desc *desc, u32 flag)
 159 {
 160         u32 mask_bits = desc->masked;
 161         unsigned offset = desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
 162                                         PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET;
 163         mask_bits &= ~1;
 164         mask_bits |= flag;
 165         writel(mask_bits, desc->mask_base + offset);
 166         desc->masked = mask_bits;
 167 }
 168
 169 static void msi_set_mask_bit(unsigned irq, u32 flag)
 170 {
 171         struct msi_desc *desc = get_irq_msi(irq);
 172
 173         if (desc->msi_attrib.is_msix) {
 174                 msix_mask_irq(desc, flag);
 175                 readl(desc->mask_base);         /* Flush write to device */
 176         } else {
 177                 unsigned offset = irq - desc->dev->irq;
 178                 msi_mask_irq(desc, 1 << offset, flag << offset);
 179         }
 180 }
 181
 182 void mask_msi_irq(unsigned int irq)
 183 {
 184         msi_set_mask_bit(irq, 1);
 185 }
 186
 187 void unmask_msi_irq(unsigned int irq)
 188 {
 189         msi_set_mask_bit(irq, 0);
 190 }
 191
 192 void read_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg)
 193 {
 194         struct msi_desc *entry = get_irq_desc_msi(desc);
 195         if (entry->msi_attrib.is_msix) {
 196                 void __iomem *base = entry->mask_base +
 197                         entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
 198
 199                 msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
 200                 msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
 201                 msg->data = readl(base + PCI_MSIX_ENTRY_DATA_OFFSET);
 202         } else {
 203                 struct pci_dev *dev = entry->dev;
 204                 int pos = entry->msi_attrib.pos;
 205                 u16 data;
 206
 207                 pci_read_config_dword(dev, msi_lower_address_reg(pos),
 208                                         &msg->address_lo);
 209                 if (entry->msi_attrib.is_64) {
 210                         pci_read_config_dword(dev, msi_upper_address_reg(pos),
 211                                                 &msg->address_hi);
 212                         pci_read_config_word(dev, msi_data_reg(pos, 1), &data);
 213                 } else {
 214                         msg->address_hi = 0;
 215                         pci_read_config_word(dev, msi_data_reg(pos, 0), &data);
 216                 }
 217                 msg->data = data;
 218         }
 219 }
 220
 221 void read_msi_msg(unsigned int irq, struct msi_msg *msg)
 222 {
 223         struct irq_desc *desc = irq_to_desc(irq);
 224
 225         read_msi_msg_desc(desc, msg);
 226 }
 227
 228 void write_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg)
 229 {
 230         struct msi_desc *entry = get_irq_desc_msi(desc);
 231         if (entry->msi_attrib.is_msix) {
 232                 void __iomem *base;
 233                 base = entry->mask_base +
 234                         entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
 235
 236                 writel(msg->address_lo,
 237                         base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
 238                 writel(msg->address_hi,
 239                         base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
 240                 writel(msg->data, base + PCI_MSIX_ENTRY_DATA_OFFSET);
 241         } else {
 242                 struct pci_dev *dev = entry->dev;
 243                 int pos = entry->msi_attrib.pos;
 244                 u16 msgctl;
 245
 246                 pci_read_config_word(dev, msi_control_reg(pos), &msgctl);
 247                 msgctl &= ~PCI_MSI_FLAGS_QSIZE;
 248                 msgctl |= entry->msi_attrib.multiple << 4;
 249                 pci_write_config_word(dev, msi_control_reg(pos), msgctl);
 250
 251                 pci_write_config_dword(dev, msi_lower_address_reg(pos),
 252                                         msg->address_lo);
 253                 if (entry->msi_attrib.is_64) {
 254                         pci_write_config_dword(dev, msi_upper_address_reg(pos),
 255                                                 msg->address_hi);
 256                         pci_write_config_word(dev, msi_data_reg(pos, 1),
 257                                                 msg->data);
 258                 } else {
 259                         pci_write_config_word(dev, msi_data_reg(pos, 0),
 260                                                 msg->data);
 261                 }
 262         }
 263         entry->msg = *msg;
 264 }
 265
 266 void write_msi_msg(unsigned int irq, struct msi_msg *msg)
 267 {
 268         struct irq_desc *desc = irq_to_desc(irq);
 269
 270         write_msi_msg_desc(desc, msg);
 271 }
 272
 273 static int msi_free_irqs(struct pci_dev* dev);
 274
 275 static struct msi_desc *alloc_msi_entry(struct pci_dev *dev)
 276 {
 277         struct msi_desc *desc = kzalloc(sizeof(*desc), GFP_KERNEL);
 278         if (!desc)
 279                 return NULL;
 280
 281         INIT_LIST_HEAD(&desc->list);
 282         desc->dev = dev;
 283
 284         return desc;
 285 }
 286
 287 static void pci_intx_for_msi(struct pci_dev *dev, int enable)
 288 {
 289         if (!(dev->dev_flags & PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG))
 290                 pci_intx(dev, enable);
 291 }
 292
 293 static void __pci_restore_msi_state(struct pci_dev *dev)
 294 {
 295         int pos;
 296         u16 control;
 297         struct msi_desc *entry;
 298
 299         if (!dev->msi_enabled)
 300                 return;
 301
 302         entry = get_irq_msi(dev->irq);
 303         pos = entry->msi_attrib.pos;
 304
 305         pci_intx_for_msi(dev, 0);
 306         msi_set_enable(dev, 0);
 307         write_msi_msg(dev->irq, &entry->msg);
 308
 309         pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
 310         msi_mask_irq(entry, msi_capable_mask(control), entry->masked);
 311         control &= ~PCI_MSI_FLAGS_QSIZE;
 312         control |= (entry->msi_attrib.multiple << 4) | PCI_MSI_FLAGS_ENABLE;
 313         pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
 314 }
 315
 316 static void __pci_restore_msix_state(struct pci_dev *dev)
 317 {
 318         int pos;
 319         struct msi_desc *entry;
 320         u16 control;
 321
 322         if (!dev->msix_enabled)
 323                 return;
 324
 325         /* route the table */
 326         pci_intx_for_msi(dev, 0);
 327         msix_set_enable(dev, 0);
 328
 329         list_for_each_entry(entry, &dev->msi_list, list) {
 330                 write_msi_msg(entry->irq, &entry->msg);
 331                 msix_mask_irq(entry, entry->masked);
 332         }
 333
 334         BUG_ON(list_empty(&dev->msi_list));
 335         entry = list_entry(dev->msi_list.next, struct msi_desc, list);
 336         pos = entry->msi_attrib.pos;
 337         pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
 338         control &= ~PCI_MSIX_FLAGS_MASKALL;
 339         control |= PCI_MSIX_FLAGS_ENABLE;
 340         pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
 341 }
 342
 343 void pci_restore_msi_state(struct pci_dev *dev)
 344 {
 345         __pci_restore_msi_state(dev);
 346         __pci_restore_msix_state(dev);
 347 }
 348 EXPORT_SYMBOL_GPL(pci_restore_msi_state);
 349
 350 /**
 351  * msi_capability_init - configure device's MSI capability structure
 352  * @dev: pointer to the pci_dev data structure of MSI device function
 353  * @nvec: number of interrupts to allocate
 354  *
 355  * Setup the MSI capability structure of the device with the requested
 356  * number of interrupts.  A return value of zero indicates the successful
 357  * setup of an entry with the new MSI irq.  A negative return value indicates
 358  * an error, and a positive return value indicates the number of interrupts
 359  * which could have been allocated.
 360  */
 361 static int msi_capability_init(struct pci_dev *dev, int nvec)
 362 {
 363         struct msi_desc *entry;
 364         int pos, ret;
 365         u16 control;
 366         unsigned mask;
 367
 368         msi_set_enable(dev, 0); /* Ensure msi is disabled as I set it up */
 369
 370         pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
 371         pci_read_config_word(dev, msi_control_reg(pos), &control);
 372         /* MSI Entry Initialization */
 373         entry = alloc_msi_entry(dev);
 374         if (!entry)
 375                 return -ENOMEM;
 376
 377         entry->msi_attrib.is_msix = 0;
 378         entry->msi_attrib.is_64 = is_64bit_address(control);
 379         entry->msi_attrib.entry_nr = 0;
 380         entry->msi_attrib.maskbit = is_mask_bit_support(control);
 381         entry->msi_attrib.default_irq = dev->irq;       /* Save IOAPIC IRQ */
 382         entry->msi_attrib.pos = pos;
 383
 384         entry->mask_pos = msi_mask_bits_reg(pos, entry->msi_attrib.is_64);
 385         /* All MSIs are unmasked by default, Mask them all */
 386         if (entry->msi_attrib.maskbit)
 387                 pci_read_config_dword(dev, entry->mask_pos, &entry->masked);
 388         mask = msi_capable_mask(control);
 389         msi_mask_irq(entry, mask, mask);
 390
 391         list_add_tail(&entry->list, &dev->msi_list);
 392
 393         /* Configure MSI capability structure */
 394         ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI);
 395         if (ret) {
 396                 msi_free_irqs(dev);
 397                 return ret;
 398         }
 399
 400         /* Set MSI enabled bits  */
 401         pci_intx_for_msi(dev, 0);
 402         msi_set_enable(dev, 1);
 403         dev->msi_enabled = 1;
 404
 405         dev->irq = entry->irq;
 406         return 0;
 407 }
 408
 409 /**
 410  * msix_capability_init - configure device's MSI-X capability
 411  * @dev: pointer to the pci_dev data structure of MSI-X device function
 412  * @entries: pointer to an array of struct msix_entry entries
 413  * @nvec: number of @entries
 414  *
 415  * Setup the MSI-X capability structure of device function with a
 416  * single MSI-X irq. A return of zero indicates the successful setup of
 417  * requested MSI-X entries with allocated irqs or non-zero for otherwise.
 418  **/
 419 static int msix_capability_init(struct pci_dev *dev,
 420                                 struct msix_entry *entries, int nvec)
 421 {
 422         struct msi_desc *entry;
 423         int pos, i, j, nr_entries, ret;
 424         unsigned long phys_addr;
 425         u32 table_offset;
 426         u16 control;
 427         u8 bir;
 428         void __iomem *base;
 429
 430         msix_set_enable(dev, 0);/* Ensure msix is disabled as I set it up */
 431
 432         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
 433         /* Request & Map MSI-X table region */
 434         pci_read_config_word(dev, msi_control_reg(pos), &control);
 435         nr_entries = multi_msix_capable(control);
 436
 437         pci_read_config_dword(dev, msix_table_offset_reg(pos), &table_offset);
 438         bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
 439         table_offset &= ~PCI_MSIX_FLAGS_BIRMASK;
 440         phys_addr = pci_resource_start (dev, bir) + table_offset;
 441         base = ioremap_nocache(phys_addr, nr_entries * PCI_MSIX_ENTRY_SIZE);
 442         if (base == NULL)
 443                 return -ENOMEM;
 444
 445         /* MSI-X Table Initialization */
 446         for (i = 0; i < nvec; i++) {
 447                 entry = alloc_msi_entry(dev);
 448                 if (!entry)
 449                         break;
 450
 451                 j = entries[i].entry;
 452                 entry->msi_attrib.is_msix = 1;
 453                 entry->msi_attrib.is_64 = 1;
 454                 entry->msi_attrib.entry_nr = j;
 455                 entry->msi_attrib.default_irq = dev->irq;
 456                 entry->msi_attrib.pos = pos;
 457                 entry->mask_base = base;
 458                 entry->masked = readl(base + j * PCI_MSIX_ENTRY_SIZE +
 459                                         PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
 460                 msix_mask_irq(entry, 1);
 461
 462                 list_add_tail(&entry->list, &dev->msi_list);
 463         }
 464
 465         ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
 466         if (ret < 0) {
 467                 /* If we had some success report the number of irqs
 468                  * we succeeded in setting up. */
 469                 int avail = 0;
 470                 list_for_each_entry(entry, &dev->msi_list, list) {
 471                         if (entry->irq != 0) {
 472                                 avail++;
 473                         }
 474                 }
 475
 476                 if (avail != 0)
 477                         ret = avail;
 478         }
 479
 480         if (ret) {
 481                 msi_free_irqs(dev);
 482                 return ret;
 483         }
 484
 485         i = 0;
 486         list_for_each_entry(entry, &dev->msi_list, list) {
 487                 entries[i].vector = entry->irq;
 488                 set_irq_msi(entry->irq, entry);
 489                 i++;
 490         }
 491         /* Set MSI-X enabled bits */
 492         pci_intx_for_msi(dev, 0);
 493         msix_set_enable(dev, 1);
 494         dev->msix_enabled = 1;
 495
 496         return 0;
 497 }
 498
 499 /**
 500  * pci_msi_check_device - check whether MSI may be enabled on a device
 501  * @dev: pointer to the pci_dev data structure of MSI device function
 502  * @nvec: how many MSIs have been requested ?
 503  * @type: are we checking for MSI or MSI-X ?
 504  *
 505  * Look at global flags, the device itself, and its parent busses
 506  * to determine if MSI/-X are supported for the device. If MSI/-X is
 507  * supported return 0, else return an error code.
 508  **/
 509 static int pci_msi_check_device(struct pci_dev* dev, int nvec, int type)
 510 {
 511         struct pci_bus *bus;
 512         int ret;
 513
 514         /* MSI must be globally enabled and supported by the device */
 515         if (!pci_msi_enable || !dev || dev->no_msi)
 516                 return -EINVAL;
 517
 518         /*
 519          * You can't ask to have 0 or less MSIs configured.
 520          *  a) it's stupid ..
 521          *  b) the list manipulation code assumes nvec >= 1.
 522          */
 523         if (nvec < 1)
 524                 return -ERANGE;
 525
 526         /* Any bridge which does NOT route MSI transactions from it's
 527          * secondary bus to it's primary bus must set NO_MSI flag on
 528          * the secondary pci_bus.
 529          * We expect only arch-specific PCI host bus controller driver
 530          * or quirks for specific PCI bridges to be setting NO_MSI.
 531          */
 532         for (bus = dev->bus; bus; bus = bus->parent)
 533                 if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
 534                         return -EINVAL;
 535
 536         ret = arch_msi_check_device(dev, nvec, type);
 537         if (ret)
 538                 return ret;
 539
 540         if (!pci_find_capability(dev, type))
 541                 return -EINVAL;
 542
 543         return 0;
 544 }
 545
 546 /**
 547  * pci_enable_msi_block - configure device's MSI capability structure
 548  * @dev: device to configure
 549  * @nvec: number of interrupts to configure
 550  *
 551  * Allocate IRQs for a device with the MSI capability.
 552  * This function returns a negative errno if an error occurs.  If it
 553  * is unable to allocate the number of interrupts requested, it returns
 554  * the number of interrupts it might be able to allocate.  If it successfully
 555  * allocates at least the number of interrupts requested, it returns 0 and
 556  * updates the @dev's irq member to the lowest new interrupt number; the
 557  * other interrupt numbers allocated to this device are consecutive.
 558  */
 559 int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec)
 560 {
 561         int status, pos, maxvec;
 562         u16 msgctl;
 563
 564         pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
 565         if (!pos)
 566                 return -EINVAL;
 567         pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl);
 568         maxvec = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
 569         if (nvec > maxvec)
 570                 return maxvec;
 571
 572         status = pci_msi_check_device(dev, nvec, PCI_CAP_ID_MSI);
 573         if (status)
 574                 return status;
 575
 576         WARN_ON(!!dev->msi_enabled);
 577
 578         /* Check whether driver already requested MSI-X irqs */
 579         if (dev->msix_enabled) {
 580                 dev_info(&dev->dev, "can't enable MSI "
 581                          "(MSI-X already enabled)\n");
 582                 return -EINVAL;
 583         }
 584
 585         status = msi_capability_init(dev, nvec);
 586         return status;
 587 }
 588 EXPORT_SYMBOL(pci_enable_msi_block);
 589
 590 void pci_msi_shutdown(struct pci_dev *dev)
 591 {
 592         struct msi_desc *desc;
 593         u32 mask;
 594         u16 ctrl;
 595
 596         if (!pci_msi_enable || !dev || !dev->msi_enabled)
 597                 return;
 598
 599         msi_set_enable(dev, 0);
 600         pci_intx_for_msi(dev, 1);
 601         dev->msi_enabled = 0;
 602
 603         BUG_ON(list_empty(&dev->msi_list));
 604         desc = list_first_entry(&dev->msi_list, struct msi_desc, list);
 605         pci_read_config_word(dev, desc->msi_attrib.pos + PCI_MSI_FLAGS, &ctrl);
 606         mask = msi_capable_mask(ctrl);
 607         msi_mask_irq(desc, mask, ~mask);
 608
 609         /* Restore dev->irq to its default pin-assertion irq */
 610         dev->irq = desc->msi_attrib.default_irq;
 611 }
 612
 613 void pci_disable_msi(struct pci_dev* dev)
 614 {
 615         struct msi_desc *entry;
 616
 617         if (!pci_msi_enable || !dev || !dev->msi_enabled)
 618                 return;
 619
 620         pci_msi_shutdown(dev);
 621
 622         entry = list_entry(dev->msi_list.next, struct msi_desc, list);
 623         if (entry->msi_attrib.is_msix)
 624                 return;
 625
 626         msi_free_irqs(dev);
 627 }
 628 EXPORT_SYMBOL(pci_disable_msi);
 629
 630 static int msi_free_irqs(struct pci_dev* dev)
 631 {
 632         struct msi_desc *entry, *tmp;
 633
 634         list_for_each_entry(entry, &dev->msi_list, list) {
 635                 int i, nvec;
 636                 if (!entry->irq)
 637                         continue;
 638                 nvec = 1 << entry->msi_attrib.multiple;
 639                 for (i = 0; i < nvec; i++)
 640                         BUG_ON(irq_has_action(entry->irq + i));
 641         }
 642
 643         arch_teardown_msi_irqs(dev);
 644
 645         list_for_each_entry_safe(entry, tmp, &dev->msi_list, list) {
 646                 if (entry->msi_attrib.is_msix) {
 647                         writel(1, entry->mask_base + entry->msi_attrib.entry_nr
 648                                   * PCI_MSIX_ENTRY_SIZE
 649                                   + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
 650
 651                         if (list_is_last(&entry->list, &dev->msi_list))
 652                                 iounmap(entry->mask_base);
 653                 }
 654                 list_del(&entry->list);
 655                 kfree(entry);
 656         }
 657
 658         return 0;
 659 }
 660
 661 /**
 662  * pci_msix_table_size - return the number of device's MSI-X table entries
 663  * @dev: pointer to the pci_dev data structure of MSI-X device function
 664  */
 665 int pci_msix_table_size(struct pci_dev *dev)
 666 {
 667         int pos;
 668         u16 control;
 669
 670         pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
 671         if (!pos)
 672                 return 0;
 673
 674         pci_read_config_word(dev, msi_control_reg(pos), &control);
 675         return multi_msix_capable(control);
 676 }
 677
 678 /**
 679  * pci_enable_msix - configure device's MSI-X capability structure
 680  * @dev: pointer to the pci_dev data structure of MSI-X device function
 681  * @entries: pointer to an array of MSI-X entries
 682  * @nvec: number of MSI-X irqs requested for allocation by device driver
 683  *
 684  * Setup the MSI-X capability structure of device function with the number
 685  * of requested irqs upon its software driver call to request for
 686  * MSI-X mode enabled on its hardware device function. A return of zero
 687  * indicates the successful configuration of MSI-X capability structure
 688  * with new allocated MSI-X irqs. A return of < 0 indicates a failure.
 689  * Or a return of > 0 indicates that driver request is exceeding the number
 690  * of irqs available. Driver should use the returned value to re-send
 691  * its request.
 692  **/
 693 int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
 694 {
 695         int status, nr_entries;
 696         int i, j;
 697
 698         if (!entries)
 699                 return -EINVAL;
 700
 701         status = pci_msi_check_device(dev, nvec, PCI_CAP_ID_MSIX);
 702         if (status)
 703                 return status;
 704
 705         nr_entries = pci_msix_table_size(dev);
 706         if (nvec > nr_entries)
 707                 return -EINVAL;
 708
 709         /* Check for any invalid entries */
 710         for (i = 0; i < nvec; i++) {
 711                 if (entries[i].entry >= nr_entries)
 712                         return -EINVAL;         /* invalid entry */
 713                 for (j = i + 1; j < nvec; j++) {
 714                         if (entries[i].entry == entries[j].entry)
 715                                 return -EINVAL; /* duplicate entry */
 716                 }
 717         }
 718         WARN_ON(!!dev->msix_enabled);
 719
 720         /* Check whether driver already requested for MSI irq */
 721         if (dev->msi_enabled) {
 722                 dev_info(&dev->dev, "can't enable MSI-X "
 723                        "(MSI IRQ already assigned)\n");
 724                 return -EINVAL;
 725         }
 726         status = msix_capability_init(dev, entries, nvec);
 727         return status;
 728 }
 729 EXPORT_SYMBOL(pci_enable_msix);
 730
 731 static void msix_free_all_irqs(struct pci_dev *dev)
 732 {
 733         msi_free_irqs(dev);
 734 }
 735
 736 void pci_msix_shutdown(struct pci_dev* dev)
 737 {
 738         if (!pci_msi_enable || !dev || !dev->msix_enabled)
 739                 return;
 740
 741         msix_set_enable(dev, 0);
 742         pci_intx_for_msi(dev, 1);
 743         dev->msix_enabled = 0;
 744 }
 745 void pci_disable_msix(struct pci_dev* dev)
 746 {
 747         if (!pci_msi_enable || !dev || !dev->msix_enabled)
 748                 return;
 749
 750         pci_msix_shutdown(dev);
 751
 752         msix_free_all_irqs(dev);
 753 }
 754 EXPORT_SYMBOL(pci_disable_msix);
 755
 756 /**
 757  * msi_remove_pci_irq_vectors - reclaim MSI(X) irqs to unused state
 758  * @dev: pointer to the pci_dev data structure of MSI(X) device function
 759  *
 760  * Being called during hotplug remove, from which the device function
 761  * is hot-removed. All previous assigned MSI/MSI-X irqs, if
 762  * allocated for this device function, are reclaimed to unused state,
 763  * which may be used later on.
 764  **/
 765 void msi_remove_pci_irq_vectors(struct pci_dev* dev)
 766 {
 767         if (!pci_msi_enable || !dev)
 768                 return;
 769
 770         if (dev->msi_enabled)
 771                 msi_free_irqs(dev);
 772
 773         if (dev->msix_enabled)
 774                 msix_free_all_irqs(dev);
 775 }
 776
 777 void pci_no_msi(void)
 778 {
 779         pci_msi_enable = 0;
 780 }
 781
 782 /**
 783  * pci_msi_enabled - is MSI enabled?
 784  *
 785  * Returns true if MSI has not been disabled by the command-line option
 786  * pci=nomsi.
 787  **/
 788 int pci_msi_enabled(void)
 789 {
 790         return pci_msi_enable;
 791 }
 792 EXPORT_SYMBOL(pci_msi_enabled);
 793
 794 void pci_msi_init_pci_dev(struct pci_dev *dev)
 795 {
 796         INIT_LIST_HEAD(&dev->msi_list);
 797 }