3 * Purpose: PCI Message Signaled Interrupt (MSI)
5 * Copyright (C) 2003-2004 Intel
6 * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com)
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>
20 #include <asm/errno.h>
26 static int pci_msi_enable = 1;
30 #ifndef arch_msi_check_device
31 int arch_msi_check_device(struct pci_dev *dev, int nvec, int type)
37 #ifndef arch_setup_msi_irqs
38 int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
40 struct msi_desc *entry;
44 * If an architecture wants to support multiple MSI, it needs to
45 * override arch_setup_msi_irqs()
47 if (type == PCI_CAP_ID_MSI && nvec > 1)
50 list_for_each_entry(entry, &dev->msi_list, list) {
51 ret = arch_setup_msi_irq(dev, entry);
62 #ifndef arch_teardown_msi_irqs
63 void arch_teardown_msi_irqs(struct pci_dev *dev)
65 struct msi_desc *entry;
67 list_for_each_entry(entry, &dev->msi_list, list) {
71 nvec = 1 << entry->msi_attrib.multiple;
72 for (i = 0; i < nvec; i++)
73 arch_teardown_msi_irq(entry->irq + i);
78 static void msi_set_enable(struct pci_dev *dev, int pos, int enable)
84 pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
85 control &= ~PCI_MSI_FLAGS_ENABLE;
87 control |= PCI_MSI_FLAGS_ENABLE;
88 pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
91 static void msix_set_enable(struct pci_dev *dev, int enable)
96 pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
98 pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
99 control &= ~PCI_MSIX_FLAGS_ENABLE;
101 control |= PCI_MSIX_FLAGS_ENABLE;
102 pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
106 static inline __attribute_const__ u32 msi_mask(unsigned x)
108 /* Don't shift by >= width of type */
111 return (1 << (1 << x)) - 1;
114 static inline __attribute_const__ u32 msi_capable_mask(u16 control)
116 return msi_mask((control >> 1) & 7);
119 static inline __attribute_const__ u32 msi_enabled_mask(u16 control)
121 return msi_mask((control >> 4) & 7);
125 * PCI 2.3 does not specify mask bits for each MSI interrupt. Attempting to
126 * mask all MSI interrupts by clearing the MSI enable bit does not work
127 * reliably as devices without an INTx disable bit will then generate a
128 * level IRQ which will never be cleared.
130 static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
132 u32 mask_bits = desc->masked;
134 if (!desc->msi_attrib.maskbit)
139 pci_write_config_dword(desc->dev, desc->mask_pos, mask_bits);
140 desc->masked = mask_bits;
144 * This internal function does not flush PCI writes to the device.
145 * All users must ensure that they read from the device before either
146 * assuming that the device state is up to date, or returning out of this
147 * file. This saves a few milliseconds when initialising devices with lots
148 * of MSI-X interrupts.
150 static void msix_mask_irq(struct msi_desc *desc, u32 flag)
152 u32 mask_bits = desc->masked;
153 unsigned offset = desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
154 PCI_MSIX_ENTRY_VECTOR_CTRL;
157 writel(mask_bits, desc->mask_base + offset);
158 desc->masked = mask_bits;
161 static void msi_set_mask_bit(unsigned irq, u32 flag)
163 struct msi_desc *desc = get_irq_msi(irq);
165 if (desc->msi_attrib.is_msix) {
166 msix_mask_irq(desc, flag);
167 readl(desc->mask_base); /* Flush write to device */
169 unsigned offset = irq - desc->dev->irq;
170 msi_mask_irq(desc, 1 << offset, flag << offset);
174 void mask_msi_irq(unsigned int irq)
176 msi_set_mask_bit(irq, 1);
179 void unmask_msi_irq(unsigned int irq)
181 msi_set_mask_bit(irq, 0);
184 void read_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg)
186 struct msi_desc *entry = get_irq_desc_msi(desc);
187 if (entry->msi_attrib.is_msix) {
188 void __iomem *base = entry->mask_base +
189 entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
191 msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR);
192 msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR);
193 msg->data = readl(base + PCI_MSIX_ENTRY_DATA);
195 struct pci_dev *dev = entry->dev;
196 int pos = entry->msi_attrib.pos;
199 pci_read_config_dword(dev, msi_lower_address_reg(pos),
201 if (entry->msi_attrib.is_64) {
202 pci_read_config_dword(dev, msi_upper_address_reg(pos),
204 pci_read_config_word(dev, msi_data_reg(pos, 1), &data);
207 pci_read_config_word(dev, msi_data_reg(pos, 0), &data);
213 void read_msi_msg(unsigned int irq, struct msi_msg *msg)
215 struct irq_desc *desc = irq_to_desc(irq);
217 read_msi_msg_desc(desc, msg);
220 void write_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg)
222 struct msi_desc *entry = get_irq_desc_msi(desc);
223 if (entry->msi_attrib.is_msix) {
225 base = entry->mask_base +
226 entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
228 writel(msg->address_lo, base + PCI_MSIX_ENTRY_LOWER_ADDR);
229 writel(msg->address_hi, base + PCI_MSIX_ENTRY_UPPER_ADDR);
230 writel(msg->data, base + PCI_MSIX_ENTRY_DATA);
232 struct pci_dev *dev = entry->dev;
233 int pos = entry->msi_attrib.pos;
236 pci_read_config_word(dev, msi_control_reg(pos), &msgctl);
237 msgctl &= ~PCI_MSI_FLAGS_QSIZE;
238 msgctl |= entry->msi_attrib.multiple << 4;
239 pci_write_config_word(dev, msi_control_reg(pos), msgctl);
241 pci_write_config_dword(dev, msi_lower_address_reg(pos),
243 if (entry->msi_attrib.is_64) {
244 pci_write_config_dword(dev, msi_upper_address_reg(pos),
246 pci_write_config_word(dev, msi_data_reg(pos, 1),
249 pci_write_config_word(dev, msi_data_reg(pos, 0),
256 void write_msi_msg(unsigned int irq, struct msi_msg *msg)
258 struct irq_desc *desc = irq_to_desc(irq);
260 write_msi_msg_desc(desc, msg);
263 static int msi_free_irqs(struct pci_dev* dev);
265 static struct msi_desc *alloc_msi_entry(struct pci_dev *dev)
267 struct msi_desc *desc = kzalloc(sizeof(*desc), GFP_KERNEL);
271 INIT_LIST_HEAD(&desc->list);
277 static void pci_intx_for_msi(struct pci_dev *dev, int enable)
279 if (!(dev->dev_flags & PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG))
280 pci_intx(dev, enable);
283 static void __pci_restore_msi_state(struct pci_dev *dev)
287 struct msi_desc *entry;
289 if (!dev->msi_enabled)
292 entry = get_irq_msi(dev->irq);
293 pos = entry->msi_attrib.pos;
295 pci_intx_for_msi(dev, 0);
296 msi_set_enable(dev, pos, 0);
297 write_msi_msg(dev->irq, &entry->msg);
299 pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
300 msi_mask_irq(entry, msi_capable_mask(control), entry->masked);
301 control &= ~PCI_MSI_FLAGS_QSIZE;
302 control |= (entry->msi_attrib.multiple << 4) | PCI_MSI_FLAGS_ENABLE;
303 pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
306 static void __pci_restore_msix_state(struct pci_dev *dev)
309 struct msi_desc *entry;
312 if (!dev->msix_enabled)
314 BUG_ON(list_empty(&dev->msi_list));
315 entry = list_entry(dev->msi_list.next, struct msi_desc, list);
316 pos = entry->msi_attrib.pos;
317 pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
319 /* route the table */
320 pci_intx_for_msi(dev, 0);
321 control |= PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL;
322 pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
324 list_for_each_entry(entry, &dev->msi_list, list) {
325 write_msi_msg(entry->irq, &entry->msg);
326 msix_mask_irq(entry, entry->masked);
329 control &= ~PCI_MSIX_FLAGS_MASKALL;
330 pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
333 void pci_restore_msi_state(struct pci_dev *dev)
335 __pci_restore_msi_state(dev);
336 __pci_restore_msix_state(dev);
338 EXPORT_SYMBOL_GPL(pci_restore_msi_state);
341 * msi_capability_init - configure device's MSI capability structure
342 * @dev: pointer to the pci_dev data structure of MSI device function
343 * @nvec: number of interrupts to allocate
345 * Setup the MSI capability structure of the device with the requested
346 * number of interrupts. A return value of zero indicates the successful
347 * setup of an entry with the new MSI irq. A negative return value indicates
348 * an error, and a positive return value indicates the number of interrupts
349 * which could have been allocated.
351 static int msi_capability_init(struct pci_dev *dev, int nvec)
353 struct msi_desc *entry;
358 pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
359 msi_set_enable(dev, pos, 0); /* Disable MSI during set up */
361 pci_read_config_word(dev, msi_control_reg(pos), &control);
362 /* MSI Entry Initialization */
363 entry = alloc_msi_entry(dev);
367 entry->msi_attrib.is_msix = 0;
368 entry->msi_attrib.is_64 = is_64bit_address(control);
369 entry->msi_attrib.entry_nr = 0;
370 entry->msi_attrib.maskbit = is_mask_bit_support(control);
371 entry->msi_attrib.default_irq = dev->irq; /* Save IOAPIC IRQ */
372 entry->msi_attrib.pos = pos;
374 entry->mask_pos = msi_mask_reg(pos, entry->msi_attrib.is_64);
375 /* All MSIs are unmasked by default, Mask them all */
376 if (entry->msi_attrib.maskbit)
377 pci_read_config_dword(dev, entry->mask_pos, &entry->masked);
378 mask = msi_capable_mask(control);
379 msi_mask_irq(entry, mask, mask);
381 list_add_tail(&entry->list, &dev->msi_list);
383 /* Configure MSI capability structure */
384 ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI);
386 msi_mask_irq(entry, mask, ~mask);
391 /* Set MSI enabled bits */
392 pci_intx_for_msi(dev, 0);
393 msi_set_enable(dev, pos, 1);
394 dev->msi_enabled = 1;
396 dev->irq = entry->irq;
401 * msix_capability_init - configure device's MSI-X capability
402 * @dev: pointer to the pci_dev data structure of MSI-X device function
403 * @entries: pointer to an array of struct msix_entry entries
404 * @nvec: number of @entries
406 * Setup the MSI-X capability structure of device function with a
407 * single MSI-X irq. A return of zero indicates the successful setup of
408 * requested MSI-X entries with allocated irqs or non-zero for otherwise.
410 static int msix_capability_init(struct pci_dev *dev,
411 struct msix_entry *entries, int nvec)
413 struct msi_desc *entry;
414 int pos, i, j, nr_entries, ret;
415 unsigned long phys_addr;
421 pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
422 pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
424 /* Ensure MSI-X is disabled while it is set up */
425 control &= ~PCI_MSIX_FLAGS_ENABLE;
426 pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
428 /* Request & Map MSI-X table region */
429 nr_entries = multi_msix_capable(control);
431 pci_read_config_dword(dev, msix_table_offset_reg(pos), &table_offset);
432 bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
433 table_offset &= ~PCI_MSIX_FLAGS_BIRMASK;
434 phys_addr = pci_resource_start (dev, bir) + table_offset;
435 base = ioremap_nocache(phys_addr, nr_entries * PCI_MSIX_ENTRY_SIZE);
439 for (i = 0; i < nvec; i++) {
440 entry = alloc_msi_entry(dev);
446 /* No enough memory. Don't try again */
450 j = entries[i].entry;
451 entry->msi_attrib.is_msix = 1;
452 entry->msi_attrib.is_64 = 1;
453 entry->msi_attrib.entry_nr = j;
454 entry->msi_attrib.default_irq = dev->irq;
455 entry->msi_attrib.pos = pos;
456 entry->mask_base = base;
458 list_add_tail(&entry->list, &dev->msi_list);
461 ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
463 /* If we had some success report the number of irqs
464 * we succeeded in setting up. */
466 list_for_each_entry(entry, &dev->msi_list, list) {
467 if (entry->irq != 0) {
482 * Some devices require MSI-X to be enabled before we can touch the
483 * MSI-X registers. We need to mask all the vectors to prevent
484 * interrupts coming in before they're fully set up.
486 control |= PCI_MSIX_FLAGS_MASKALL | PCI_MSIX_FLAGS_ENABLE;
487 pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
490 list_for_each_entry(entry, &dev->msi_list, list) {
491 entries[i].vector = entry->irq;
492 set_irq_msi(entry->irq, entry);
493 j = entries[i].entry;
494 entry->masked = readl(base + j * PCI_MSIX_ENTRY_SIZE +
495 PCI_MSIX_ENTRY_VECTOR_CTRL);
496 msix_mask_irq(entry, 1);
500 /* Set MSI-X enabled bits and unmask the function */
501 pci_intx_for_msi(dev, 0);
502 dev->msix_enabled = 1;
504 control &= ~PCI_MSIX_FLAGS_MASKALL;
505 pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
511 * pci_msi_check_device - check whether MSI may be enabled on a device
512 * @dev: pointer to the pci_dev data structure of MSI device function
513 * @nvec: how many MSIs have been requested ?
514 * @type: are we checking for MSI or MSI-X ?
516 * Look at global flags, the device itself, and its parent busses
517 * to determine if MSI/-X are supported for the device. If MSI/-X is
518 * supported return 0, else return an error code.
520 static int pci_msi_check_device(struct pci_dev* dev, int nvec, int type)
525 /* MSI must be globally enabled and supported by the device */
526 if (!pci_msi_enable || !dev || dev->no_msi)
530 * You can't ask to have 0 or less MSIs configured.
532 * b) the list manipulation code assumes nvec >= 1.
537 /* Any bridge which does NOT route MSI transactions from it's
538 * secondary bus to it's primary bus must set NO_MSI flag on
539 * the secondary pci_bus.
540 * We expect only arch-specific PCI host bus controller driver
541 * or quirks for specific PCI bridges to be setting NO_MSI.
543 for (bus = dev->bus; bus; bus = bus->parent)
544 if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
547 ret = arch_msi_check_device(dev, nvec, type);
551 if (!pci_find_capability(dev, type))
558 * pci_enable_msi_block - configure device's MSI capability structure
559 * @dev: device to configure
560 * @nvec: number of interrupts to configure
562 * Allocate IRQs for a device with the MSI capability.
563 * This function returns a negative errno if an error occurs. If it
564 * is unable to allocate the number of interrupts requested, it returns
565 * the number of interrupts it might be able to allocate. If it successfully
566 * allocates at least the number of interrupts requested, it returns 0 and
567 * updates the @dev's irq member to the lowest new interrupt number; the
568 * other interrupt numbers allocated to this device are consecutive.
570 int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec)
572 int status, pos, maxvec;
575 pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
578 pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl);
579 maxvec = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
583 status = pci_msi_check_device(dev, nvec, PCI_CAP_ID_MSI);
587 WARN_ON(!!dev->msi_enabled);
589 /* Check whether driver already requested MSI-X irqs */
590 if (dev->msix_enabled) {
591 dev_info(&dev->dev, "can't enable MSI "
592 "(MSI-X already enabled)\n");
596 status = msi_capability_init(dev, nvec);
599 EXPORT_SYMBOL(pci_enable_msi_block);
601 void pci_msi_shutdown(struct pci_dev *dev)
603 struct msi_desc *desc;
608 if (!pci_msi_enable || !dev || !dev->msi_enabled)
611 BUG_ON(list_empty(&dev->msi_list));
612 desc = list_first_entry(&dev->msi_list, struct msi_desc, list);
613 pos = desc->msi_attrib.pos;
615 msi_set_enable(dev, pos, 0);
616 pci_intx_for_msi(dev, 1);
617 dev->msi_enabled = 0;
619 pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &ctrl);
620 mask = msi_capable_mask(ctrl);
621 msi_mask_irq(desc, mask, ~mask);
623 /* Restore dev->irq to its default pin-assertion irq */
624 dev->irq = desc->msi_attrib.default_irq;
627 void pci_disable_msi(struct pci_dev* dev)
629 struct msi_desc *entry;
631 if (!pci_msi_enable || !dev || !dev->msi_enabled)
634 pci_msi_shutdown(dev);
636 entry = list_entry(dev->msi_list.next, struct msi_desc, list);
637 if (entry->msi_attrib.is_msix)
642 EXPORT_SYMBOL(pci_disable_msi);
644 static int msi_free_irqs(struct pci_dev* dev)
646 struct msi_desc *entry, *tmp;
648 list_for_each_entry(entry, &dev->msi_list, list) {
652 nvec = 1 << entry->msi_attrib.multiple;
653 for (i = 0; i < nvec; i++)
654 BUG_ON(irq_has_action(entry->irq + i));
657 arch_teardown_msi_irqs(dev);
659 list_for_each_entry_safe(entry, tmp, &dev->msi_list, list) {
660 if (entry->msi_attrib.is_msix) {
661 msix_mask_irq(entry, 1);
662 if (list_is_last(&entry->list, &dev->msi_list))
663 iounmap(entry->mask_base);
665 list_del(&entry->list);
673 * pci_msix_table_size - return the number of device's MSI-X table entries
674 * @dev: pointer to the pci_dev data structure of MSI-X device function
676 int pci_msix_table_size(struct pci_dev *dev)
681 pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
685 pci_read_config_word(dev, msi_control_reg(pos), &control);
686 return multi_msix_capable(control);
690 * pci_enable_msix - configure device's MSI-X capability structure
691 * @dev: pointer to the pci_dev data structure of MSI-X device function
692 * @entries: pointer to an array of MSI-X entries
693 * @nvec: number of MSI-X irqs requested for allocation by device driver
695 * Setup the MSI-X capability structure of device function with the number
696 * of requested irqs upon its software driver call to request for
697 * MSI-X mode enabled on its hardware device function. A return of zero
698 * indicates the successful configuration of MSI-X capability structure
699 * with new allocated MSI-X irqs. A return of < 0 indicates a failure.
700 * Or a return of > 0 indicates that driver request is exceeding the number
701 * of irqs or MSI-X vectors available. Driver should use the returned value to
702 * re-send its request.
704 int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
706 int status, nr_entries;
712 status = pci_msi_check_device(dev, nvec, PCI_CAP_ID_MSIX);
716 nr_entries = pci_msix_table_size(dev);
717 if (nvec > nr_entries)
720 /* Check for any invalid entries */
721 for (i = 0; i < nvec; i++) {
722 if (entries[i].entry >= nr_entries)
723 return -EINVAL; /* invalid entry */
724 for (j = i + 1; j < nvec; j++) {
725 if (entries[i].entry == entries[j].entry)
726 return -EINVAL; /* duplicate entry */
729 WARN_ON(!!dev->msix_enabled);
731 /* Check whether driver already requested for MSI irq */
732 if (dev->msi_enabled) {
733 dev_info(&dev->dev, "can't enable MSI-X "
734 "(MSI IRQ already assigned)\n");
737 status = msix_capability_init(dev, entries, nvec);
740 EXPORT_SYMBOL(pci_enable_msix);
742 static void msix_free_all_irqs(struct pci_dev *dev)
747 void pci_msix_shutdown(struct pci_dev* dev)
749 if (!pci_msi_enable || !dev || !dev->msix_enabled)
752 msix_set_enable(dev, 0);
753 pci_intx_for_msi(dev, 1);
754 dev->msix_enabled = 0;
756 void pci_disable_msix(struct pci_dev* dev)
758 if (!pci_msi_enable || !dev || !dev->msix_enabled)
761 pci_msix_shutdown(dev);
763 msix_free_all_irqs(dev);
765 EXPORT_SYMBOL(pci_disable_msix);
768 * msi_remove_pci_irq_vectors - reclaim MSI(X) irqs to unused state
769 * @dev: pointer to the pci_dev data structure of MSI(X) device function
771 * Being called during hotplug remove, from which the device function
772 * is hot-removed. All previous assigned MSI/MSI-X irqs, if
773 * allocated for this device function, are reclaimed to unused state,
774 * which may be used later on.
776 void msi_remove_pci_irq_vectors(struct pci_dev* dev)
778 if (!pci_msi_enable || !dev)
781 if (dev->msi_enabled)
784 if (dev->msix_enabled)
785 msix_free_all_irqs(dev);
788 void pci_no_msi(void)
794 * pci_msi_enabled - is MSI enabled?
796 * Returns true if MSI has not been disabled by the command-line option
799 int pci_msi_enabled(void)
801 return pci_msi_enable;
803 EXPORT_SYMBOL(pci_msi_enabled);
805 void pci_msi_init_pci_dev(struct pci_dev *dev)
807 INIT_LIST_HEAD(&dev->msi_list);