Linux 4.19.133
[linux/fpc-iii.git] / drivers / pci / msi.c
blob23a363fd4c59cf91e4a098dae390a8d0fd626022
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * PCI Message Signaled Interrupt (MSI)
5 * Copyright (C) 2003-2004 Intel
6 * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com)
7 * Copyright (C) 2016 Christoph Hellwig.
8 */
10 #include <linux/err.h>
11 #include <linux/mm.h>
12 #include <linux/irq.h>
13 #include <linux/interrupt.h>
14 #include <linux/export.h>
15 #include <linux/ioport.h>
16 #include <linux/pci.h>
17 #include <linux/proc_fs.h>
18 #include <linux/msi.h>
19 #include <linux/smp.h>
20 #include <linux/errno.h>
21 #include <linux/io.h>
22 #include <linux/acpi_iort.h>
23 #include <linux/slab.h>
24 #include <linux/irqdomain.h>
25 #include <linux/of_irq.h>
27 #include "pci.h"
29 static int pci_msi_enable = 1;
30 int pci_msi_ignore_mask;
32 #define msix_table_size(flags) ((flags & PCI_MSIX_FLAGS_QSIZE) + 1)
34 #ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
35 static int pci_msi_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
37 struct irq_domain *domain;
39 domain = dev_get_msi_domain(&dev->dev);
40 if (domain && irq_domain_is_hierarchy(domain))
41 return msi_domain_alloc_irqs(domain, &dev->dev, nvec);
43 return arch_setup_msi_irqs(dev, nvec, type);
46 static void pci_msi_teardown_msi_irqs(struct pci_dev *dev)
48 struct irq_domain *domain;
50 domain = dev_get_msi_domain(&dev->dev);
51 if (domain && irq_domain_is_hierarchy(domain))
52 msi_domain_free_irqs(domain, &dev->dev);
53 else
54 arch_teardown_msi_irqs(dev);
56 #else
57 #define pci_msi_setup_msi_irqs arch_setup_msi_irqs
58 #define pci_msi_teardown_msi_irqs arch_teardown_msi_irqs
59 #endif
61 /* Arch hooks */
63 int __weak arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
65 struct msi_controller *chip = dev->bus->msi;
66 int err;
68 if (!chip || !chip->setup_irq)
69 return -EINVAL;
71 err = chip->setup_irq(chip, dev, desc);
72 if (err < 0)
73 return err;
75 irq_set_chip_data(desc->irq, chip);
77 return 0;
80 void __weak arch_teardown_msi_irq(unsigned int irq)
82 struct msi_controller *chip = irq_get_chip_data(irq);
84 if (!chip || !chip->teardown_irq)
85 return;
87 chip->teardown_irq(chip, irq);
90 int __weak arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
92 struct msi_controller *chip = dev->bus->msi;
93 struct msi_desc *entry;
94 int ret;
96 if (chip && chip->setup_irqs)
97 return chip->setup_irqs(chip, dev, nvec, type);
99 * If an architecture wants to support multiple MSI, it needs to
100 * override arch_setup_msi_irqs()
102 if (type == PCI_CAP_ID_MSI && nvec > 1)
103 return 1;
105 for_each_pci_msi_entry(entry, dev) {
106 ret = arch_setup_msi_irq(dev, entry);
107 if (ret < 0)
108 return ret;
109 if (ret > 0)
110 return -ENOSPC;
113 return 0;
117 * We have a default implementation available as a separate non-weak
118 * function, as it is used by the Xen x86 PCI code
120 void default_teardown_msi_irqs(struct pci_dev *dev)
122 int i;
123 struct msi_desc *entry;
125 for_each_pci_msi_entry(entry, dev)
126 if (entry->irq)
127 for (i = 0; i < entry->nvec_used; i++)
128 arch_teardown_msi_irq(entry->irq + i);
131 void __weak arch_teardown_msi_irqs(struct pci_dev *dev)
133 return default_teardown_msi_irqs(dev);
136 static void default_restore_msi_irq(struct pci_dev *dev, int irq)
138 struct msi_desc *entry;
140 entry = NULL;
141 if (dev->msix_enabled) {
142 for_each_pci_msi_entry(entry, dev) {
143 if (irq == entry->irq)
144 break;
146 } else if (dev->msi_enabled) {
147 entry = irq_get_msi_desc(irq);
150 if (entry)
151 __pci_write_msi_msg(entry, &entry->msg);
154 void __weak arch_restore_msi_irqs(struct pci_dev *dev)
156 return default_restore_msi_irqs(dev);
159 static inline __attribute_const__ u32 msi_mask(unsigned x)
161 /* Don't shift by >= width of type */
162 if (x >= 5)
163 return 0xffffffff;
164 return (1 << (1 << x)) - 1;
168 * PCI 2.3 does not specify mask bits for each MSI interrupt. Attempting to
169 * mask all MSI interrupts by clearing the MSI enable bit does not work
170 * reliably as devices without an INTx disable bit will then generate a
171 * level IRQ which will never be cleared.
173 u32 __pci_msi_desc_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
175 u32 mask_bits = desc->masked;
177 if (pci_msi_ignore_mask || !desc->msi_attrib.maskbit)
178 return 0;
180 mask_bits &= ~mask;
181 mask_bits |= flag;
182 pci_write_config_dword(msi_desc_to_pci_dev(desc), desc->mask_pos,
183 mask_bits);
185 return mask_bits;
188 static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
190 desc->masked = __pci_msi_desc_mask_irq(desc, mask, flag);
193 static void __iomem *pci_msix_desc_addr(struct msi_desc *desc)
195 return desc->mask_base +
196 desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
200 * This internal function does not flush PCI writes to the device.
201 * All users must ensure that they read from the device before either
202 * assuming that the device state is up to date, or returning out of this
203 * file. This saves a few milliseconds when initialising devices with lots
204 * of MSI-X interrupts.
206 u32 __pci_msix_desc_mask_irq(struct msi_desc *desc, u32 flag)
208 u32 mask_bits = desc->masked;
210 if (pci_msi_ignore_mask)
211 return 0;
213 mask_bits &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT;
214 if (flag & PCI_MSIX_ENTRY_CTRL_MASKBIT)
215 mask_bits |= PCI_MSIX_ENTRY_CTRL_MASKBIT;
216 writel(mask_bits, pci_msix_desc_addr(desc) + PCI_MSIX_ENTRY_VECTOR_CTRL);
218 return mask_bits;
221 static void msix_mask_irq(struct msi_desc *desc, u32 flag)
223 desc->masked = __pci_msix_desc_mask_irq(desc, flag);
226 static void msi_set_mask_bit(struct irq_data *data, u32 flag)
228 struct msi_desc *desc = irq_data_get_msi_desc(data);
230 if (desc->msi_attrib.is_msix) {
231 msix_mask_irq(desc, flag);
232 readl(desc->mask_base); /* Flush write to device */
233 } else {
234 unsigned offset = data->irq - desc->irq;
235 msi_mask_irq(desc, 1 << offset, flag << offset);
240 * pci_msi_mask_irq - Generic irq chip callback to mask PCI/MSI interrupts
241 * @data: pointer to irqdata associated to that interrupt
243 void pci_msi_mask_irq(struct irq_data *data)
245 msi_set_mask_bit(data, 1);
247 EXPORT_SYMBOL_GPL(pci_msi_mask_irq);
250 * pci_msi_unmask_irq - Generic irq chip callback to unmask PCI/MSI interrupts
251 * @data: pointer to irqdata associated to that interrupt
253 void pci_msi_unmask_irq(struct irq_data *data)
255 msi_set_mask_bit(data, 0);
257 EXPORT_SYMBOL_GPL(pci_msi_unmask_irq);
259 void default_restore_msi_irqs(struct pci_dev *dev)
261 struct msi_desc *entry;
263 for_each_pci_msi_entry(entry, dev)
264 default_restore_msi_irq(dev, entry->irq);
267 void __pci_read_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
269 struct pci_dev *dev = msi_desc_to_pci_dev(entry);
271 BUG_ON(dev->current_state != PCI_D0);
273 if (entry->msi_attrib.is_msix) {
274 void __iomem *base = pci_msix_desc_addr(entry);
276 msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR);
277 msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR);
278 msg->data = readl(base + PCI_MSIX_ENTRY_DATA);
279 } else {
280 int pos = dev->msi_cap;
281 u16 data;
283 pci_read_config_dword(dev, pos + PCI_MSI_ADDRESS_LO,
284 &msg->address_lo);
285 if (entry->msi_attrib.is_64) {
286 pci_read_config_dword(dev, pos + PCI_MSI_ADDRESS_HI,
287 &msg->address_hi);
288 pci_read_config_word(dev, pos + PCI_MSI_DATA_64, &data);
289 } else {
290 msg->address_hi = 0;
291 pci_read_config_word(dev, pos + PCI_MSI_DATA_32, &data);
293 msg->data = data;
297 void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
299 struct pci_dev *dev = msi_desc_to_pci_dev(entry);
301 if (dev->current_state != PCI_D0 || pci_dev_is_disconnected(dev)) {
302 /* Don't touch the hardware now */
303 } else if (entry->msi_attrib.is_msix) {
304 void __iomem *base = pci_msix_desc_addr(entry);
306 writel(msg->address_lo, base + PCI_MSIX_ENTRY_LOWER_ADDR);
307 writel(msg->address_hi, base + PCI_MSIX_ENTRY_UPPER_ADDR);
308 writel(msg->data, base + PCI_MSIX_ENTRY_DATA);
309 } else {
310 int pos = dev->msi_cap;
311 u16 msgctl;
313 pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl);
314 msgctl &= ~PCI_MSI_FLAGS_QSIZE;
315 msgctl |= entry->msi_attrib.multiple << 4;
316 pci_write_config_word(dev, pos + PCI_MSI_FLAGS, msgctl);
318 pci_write_config_dword(dev, pos + PCI_MSI_ADDRESS_LO,
319 msg->address_lo);
320 if (entry->msi_attrib.is_64) {
321 pci_write_config_dword(dev, pos + PCI_MSI_ADDRESS_HI,
322 msg->address_hi);
323 pci_write_config_word(dev, pos + PCI_MSI_DATA_64,
324 msg->data);
325 } else {
326 pci_write_config_word(dev, pos + PCI_MSI_DATA_32,
327 msg->data);
330 entry->msg = *msg;
333 void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg)
335 struct msi_desc *entry = irq_get_msi_desc(irq);
337 __pci_write_msi_msg(entry, msg);
339 EXPORT_SYMBOL_GPL(pci_write_msi_msg);
341 static void free_msi_irqs(struct pci_dev *dev)
343 struct list_head *msi_list = dev_to_msi_list(&dev->dev);
344 struct msi_desc *entry, *tmp;
345 struct attribute **msi_attrs;
346 struct device_attribute *dev_attr;
347 int i, count = 0;
349 for_each_pci_msi_entry(entry, dev)
350 if (entry->irq)
351 for (i = 0; i < entry->nvec_used; i++)
352 BUG_ON(irq_has_action(entry->irq + i));
354 pci_msi_teardown_msi_irqs(dev);
356 list_for_each_entry_safe(entry, tmp, msi_list, list) {
357 if (entry->msi_attrib.is_msix) {
358 if (list_is_last(&entry->list, msi_list))
359 iounmap(entry->mask_base);
362 list_del(&entry->list);
363 free_msi_entry(entry);
366 if (dev->msi_irq_groups) {
367 sysfs_remove_groups(&dev->dev.kobj, dev->msi_irq_groups);
368 msi_attrs = dev->msi_irq_groups[0]->attrs;
369 while (msi_attrs[count]) {
370 dev_attr = container_of(msi_attrs[count],
371 struct device_attribute, attr);
372 kfree(dev_attr->attr.name);
373 kfree(dev_attr);
374 ++count;
376 kfree(msi_attrs);
377 kfree(dev->msi_irq_groups[0]);
378 kfree(dev->msi_irq_groups);
379 dev->msi_irq_groups = NULL;
383 static void pci_intx_for_msi(struct pci_dev *dev, int enable)
385 if (!(dev->dev_flags & PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG))
386 pci_intx(dev, enable);
389 static void __pci_restore_msi_state(struct pci_dev *dev)
391 u16 control;
392 struct msi_desc *entry;
394 if (!dev->msi_enabled)
395 return;
397 entry = irq_get_msi_desc(dev->irq);
399 pci_intx_for_msi(dev, 0);
400 pci_msi_set_enable(dev, 0);
401 arch_restore_msi_irqs(dev);
403 pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
404 msi_mask_irq(entry, msi_mask(entry->msi_attrib.multi_cap),
405 entry->masked);
406 control &= ~PCI_MSI_FLAGS_QSIZE;
407 control |= (entry->msi_attrib.multiple << 4) | PCI_MSI_FLAGS_ENABLE;
408 pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
411 static void __pci_restore_msix_state(struct pci_dev *dev)
413 struct msi_desc *entry;
415 if (!dev->msix_enabled)
416 return;
417 BUG_ON(list_empty(dev_to_msi_list(&dev->dev)));
419 /* route the table */
420 pci_intx_for_msi(dev, 0);
421 pci_msix_clear_and_set_ctrl(dev, 0,
422 PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL);
424 arch_restore_msi_irqs(dev);
425 for_each_pci_msi_entry(entry, dev)
426 msix_mask_irq(entry, entry->masked);
428 pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
431 void pci_restore_msi_state(struct pci_dev *dev)
433 __pci_restore_msi_state(dev);
434 __pci_restore_msix_state(dev);
436 EXPORT_SYMBOL_GPL(pci_restore_msi_state);
438 static ssize_t msi_mode_show(struct device *dev, struct device_attribute *attr,
439 char *buf)
441 struct msi_desc *entry;
442 unsigned long irq;
443 int retval;
445 retval = kstrtoul(attr->attr.name, 10, &irq);
446 if (retval)
447 return retval;
449 entry = irq_get_msi_desc(irq);
450 if (entry)
451 return sprintf(buf, "%s\n",
452 entry->msi_attrib.is_msix ? "msix" : "msi");
454 return -ENODEV;
457 static int populate_msi_sysfs(struct pci_dev *pdev)
459 struct attribute **msi_attrs;
460 struct attribute *msi_attr;
461 struct device_attribute *msi_dev_attr;
462 struct attribute_group *msi_irq_group;
463 const struct attribute_group **msi_irq_groups;
464 struct msi_desc *entry;
465 int ret = -ENOMEM;
466 int num_msi = 0;
467 int count = 0;
468 int i;
470 /* Determine how many msi entries we have */
471 for_each_pci_msi_entry(entry, pdev)
472 num_msi += entry->nvec_used;
473 if (!num_msi)
474 return 0;
476 /* Dynamically create the MSI attributes for the PCI device */
477 msi_attrs = kcalloc(num_msi + 1, sizeof(void *), GFP_KERNEL);
478 if (!msi_attrs)
479 return -ENOMEM;
480 for_each_pci_msi_entry(entry, pdev) {
481 for (i = 0; i < entry->nvec_used; i++) {
482 msi_dev_attr = kzalloc(sizeof(*msi_dev_attr), GFP_KERNEL);
483 if (!msi_dev_attr)
484 goto error_attrs;
485 msi_attrs[count] = &msi_dev_attr->attr;
487 sysfs_attr_init(&msi_dev_attr->attr);
488 msi_dev_attr->attr.name = kasprintf(GFP_KERNEL, "%d",
489 entry->irq + i);
490 if (!msi_dev_attr->attr.name)
491 goto error_attrs;
492 msi_dev_attr->attr.mode = S_IRUGO;
493 msi_dev_attr->show = msi_mode_show;
494 ++count;
498 msi_irq_group = kzalloc(sizeof(*msi_irq_group), GFP_KERNEL);
499 if (!msi_irq_group)
500 goto error_attrs;
501 msi_irq_group->name = "msi_irqs";
502 msi_irq_group->attrs = msi_attrs;
504 msi_irq_groups = kcalloc(2, sizeof(void *), GFP_KERNEL);
505 if (!msi_irq_groups)
506 goto error_irq_group;
507 msi_irq_groups[0] = msi_irq_group;
509 ret = sysfs_create_groups(&pdev->dev.kobj, msi_irq_groups);
510 if (ret)
511 goto error_irq_groups;
512 pdev->msi_irq_groups = msi_irq_groups;
514 return 0;
516 error_irq_groups:
517 kfree(msi_irq_groups);
518 error_irq_group:
519 kfree(msi_irq_group);
520 error_attrs:
521 count = 0;
522 msi_attr = msi_attrs[count];
523 while (msi_attr) {
524 msi_dev_attr = container_of(msi_attr, struct device_attribute, attr);
525 kfree(msi_attr->name);
526 kfree(msi_dev_attr);
527 ++count;
528 msi_attr = msi_attrs[count];
530 kfree(msi_attrs);
531 return ret;
534 static struct msi_desc *
535 msi_setup_entry(struct pci_dev *dev, int nvec, const struct irq_affinity *affd)
537 struct cpumask *masks = NULL;
538 struct msi_desc *entry;
539 u16 control;
541 if (affd)
542 masks = irq_create_affinity_masks(nvec, affd);
545 /* MSI Entry Initialization */
546 entry = alloc_msi_entry(&dev->dev, nvec, masks);
547 if (!entry)
548 goto out;
550 pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
552 entry->msi_attrib.is_msix = 0;
553 entry->msi_attrib.is_64 = !!(control & PCI_MSI_FLAGS_64BIT);
554 entry->msi_attrib.entry_nr = 0;
555 entry->msi_attrib.maskbit = !!(control & PCI_MSI_FLAGS_MASKBIT);
556 entry->msi_attrib.default_irq = dev->irq; /* Save IOAPIC IRQ */
557 entry->msi_attrib.multi_cap = (control & PCI_MSI_FLAGS_QMASK) >> 1;
558 entry->msi_attrib.multiple = ilog2(__roundup_pow_of_two(nvec));
560 if (control & PCI_MSI_FLAGS_64BIT)
561 entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_64;
562 else
563 entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_32;
565 /* Save the initial mask status */
566 if (entry->msi_attrib.maskbit)
567 pci_read_config_dword(dev, entry->mask_pos, &entry->masked);
569 out:
570 kfree(masks);
571 return entry;
574 static int msi_verify_entries(struct pci_dev *dev)
576 struct msi_desc *entry;
578 for_each_pci_msi_entry(entry, dev) {
579 if (!dev->no_64bit_msi || !entry->msg.address_hi)
580 continue;
581 pci_err(dev, "Device has broken 64-bit MSI but arch"
582 " tried to assign one above 4G\n");
583 return -EIO;
585 return 0;
589 * msi_capability_init - configure device's MSI capability structure
590 * @dev: pointer to the pci_dev data structure of MSI device function
591 * @nvec: number of interrupts to allocate
592 * @affd: description of automatic irq affinity assignments (may be %NULL)
594 * Setup the MSI capability structure of the device with the requested
595 * number of interrupts. A return value of zero indicates the successful
596 * setup of an entry with the new MSI irq. A negative return value indicates
597 * an error, and a positive return value indicates the number of interrupts
598 * which could have been allocated.
600 static int msi_capability_init(struct pci_dev *dev, int nvec,
601 const struct irq_affinity *affd)
603 struct msi_desc *entry;
604 int ret;
605 unsigned mask;
607 pci_msi_set_enable(dev, 0); /* Disable MSI during set up */
609 entry = msi_setup_entry(dev, nvec, affd);
610 if (!entry)
611 return -ENOMEM;
613 /* All MSIs are unmasked by default, Mask them all */
614 mask = msi_mask(entry->msi_attrib.multi_cap);
615 msi_mask_irq(entry, mask, mask);
617 list_add_tail(&entry->list, dev_to_msi_list(&dev->dev));
619 /* Configure MSI capability structure */
620 ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI);
621 if (ret) {
622 msi_mask_irq(entry, mask, ~mask);
623 free_msi_irqs(dev);
624 return ret;
627 ret = msi_verify_entries(dev);
628 if (ret) {
629 msi_mask_irq(entry, mask, ~mask);
630 free_msi_irqs(dev);
631 return ret;
634 ret = populate_msi_sysfs(dev);
635 if (ret) {
636 msi_mask_irq(entry, mask, ~mask);
637 free_msi_irqs(dev);
638 return ret;
641 /* Set MSI enabled bits */
642 pci_intx_for_msi(dev, 0);
643 pci_msi_set_enable(dev, 1);
644 dev->msi_enabled = 1;
646 pcibios_free_irq(dev);
647 dev->irq = entry->irq;
648 return 0;
651 static void __iomem *msix_map_region(struct pci_dev *dev, unsigned nr_entries)
653 resource_size_t phys_addr;
654 u32 table_offset;
655 unsigned long flags;
656 u8 bir;
658 pci_read_config_dword(dev, dev->msix_cap + PCI_MSIX_TABLE,
659 &table_offset);
660 bir = (u8)(table_offset & PCI_MSIX_TABLE_BIR);
661 flags = pci_resource_flags(dev, bir);
662 if (!flags || (flags & IORESOURCE_UNSET))
663 return NULL;
665 table_offset &= PCI_MSIX_TABLE_OFFSET;
666 phys_addr = pci_resource_start(dev, bir) + table_offset;
668 return ioremap_nocache(phys_addr, nr_entries * PCI_MSIX_ENTRY_SIZE);
671 static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
672 struct msix_entry *entries, int nvec,
673 const struct irq_affinity *affd)
675 struct cpumask *curmsk, *masks = NULL;
676 struct msi_desc *entry;
677 int ret, i;
679 if (affd)
680 masks = irq_create_affinity_masks(nvec, affd);
682 for (i = 0, curmsk = masks; i < nvec; i++) {
683 entry = alloc_msi_entry(&dev->dev, 1, curmsk);
684 if (!entry) {
685 if (!i)
686 iounmap(base);
687 else
688 free_msi_irqs(dev);
689 /* No enough memory. Don't try again */
690 ret = -ENOMEM;
691 goto out;
694 entry->msi_attrib.is_msix = 1;
695 entry->msi_attrib.is_64 = 1;
696 if (entries)
697 entry->msi_attrib.entry_nr = entries[i].entry;
698 else
699 entry->msi_attrib.entry_nr = i;
700 entry->msi_attrib.default_irq = dev->irq;
701 entry->mask_base = base;
703 list_add_tail(&entry->list, dev_to_msi_list(&dev->dev));
704 if (masks)
705 curmsk++;
707 ret = 0;
708 out:
709 kfree(masks);
710 return ret;
713 static void msix_program_entries(struct pci_dev *dev,
714 struct msix_entry *entries)
716 struct msi_desc *entry;
717 int i = 0;
719 for_each_pci_msi_entry(entry, dev) {
720 if (entries)
721 entries[i++].vector = entry->irq;
722 entry->masked = readl(pci_msix_desc_addr(entry) +
723 PCI_MSIX_ENTRY_VECTOR_CTRL);
724 msix_mask_irq(entry, 1);
729 * msix_capability_init - configure device's MSI-X capability
730 * @dev: pointer to the pci_dev data structure of MSI-X device function
731 * @entries: pointer to an array of struct msix_entry entries
732 * @nvec: number of @entries
733 * @affd: Optional pointer to enable automatic affinity assignement
735 * Setup the MSI-X capability structure of device function with a
736 * single MSI-X irq. A return of zero indicates the successful setup of
737 * requested MSI-X entries with allocated irqs or non-zero for otherwise.
739 static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries,
740 int nvec, const struct irq_affinity *affd)
742 int ret;
743 u16 control;
744 void __iomem *base;
746 /* Ensure MSI-X is disabled while it is set up */
747 pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
749 pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control);
750 /* Request & Map MSI-X table region */
751 base = msix_map_region(dev, msix_table_size(control));
752 if (!base)
753 return -ENOMEM;
755 ret = msix_setup_entries(dev, base, entries, nvec, affd);
756 if (ret)
757 return ret;
759 ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
760 if (ret)
761 goto out_avail;
763 /* Check if all MSI entries honor device restrictions */
764 ret = msi_verify_entries(dev);
765 if (ret)
766 goto out_free;
769 * Some devices require MSI-X to be enabled before we can touch the
770 * MSI-X registers. We need to mask all the vectors to prevent
771 * interrupts coming in before they're fully set up.
773 pci_msix_clear_and_set_ctrl(dev, 0,
774 PCI_MSIX_FLAGS_MASKALL | PCI_MSIX_FLAGS_ENABLE);
776 msix_program_entries(dev, entries);
778 ret = populate_msi_sysfs(dev);
779 if (ret)
780 goto out_free;
782 /* Set MSI-X enabled bits and unmask the function */
783 pci_intx_for_msi(dev, 0);
784 dev->msix_enabled = 1;
785 pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
787 pcibios_free_irq(dev);
788 return 0;
790 out_avail:
791 if (ret < 0) {
793 * If we had some success, report the number of irqs
794 * we succeeded in setting up.
796 struct msi_desc *entry;
797 int avail = 0;
799 for_each_pci_msi_entry(entry, dev) {
800 if (entry->irq != 0)
801 avail++;
803 if (avail != 0)
804 ret = avail;
807 out_free:
808 free_msi_irqs(dev);
810 return ret;
814 * pci_msi_supported - check whether MSI may be enabled on a device
815 * @dev: pointer to the pci_dev data structure of MSI device function
816 * @nvec: how many MSIs have been requested ?
818 * Look at global flags, the device itself, and its parent buses
819 * to determine if MSI/-X are supported for the device. If MSI/-X is
820 * supported return 1, else return 0.
822 static int pci_msi_supported(struct pci_dev *dev, int nvec)
824 struct pci_bus *bus;
826 /* MSI must be globally enabled and supported by the device */
827 if (!pci_msi_enable)
828 return 0;
830 if (!dev || dev->no_msi || dev->current_state != PCI_D0)
831 return 0;
834 * You can't ask to have 0 or less MSIs configured.
835 * a) it's stupid ..
836 * b) the list manipulation code assumes nvec >= 1.
838 if (nvec < 1)
839 return 0;
842 * Any bridge which does NOT route MSI transactions from its
843 * secondary bus to its primary bus must set NO_MSI flag on
844 * the secondary pci_bus.
845 * We expect only arch-specific PCI host bus controller driver
846 * or quirks for specific PCI bridges to be setting NO_MSI.
848 for (bus = dev->bus; bus; bus = bus->parent)
849 if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
850 return 0;
852 return 1;
856 * pci_msi_vec_count - Return the number of MSI vectors a device can send
857 * @dev: device to report about
859 * This function returns the number of MSI vectors a device requested via
860 * Multiple Message Capable register. It returns a negative errno if the
861 * device is not capable sending MSI interrupts. Otherwise, the call succeeds
862 * and returns a power of two, up to a maximum of 2^5 (32), according to the
863 * MSI specification.
865 int pci_msi_vec_count(struct pci_dev *dev)
867 int ret;
868 u16 msgctl;
870 if (!dev->msi_cap)
871 return -EINVAL;
873 pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &msgctl);
874 ret = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
876 return ret;
878 EXPORT_SYMBOL(pci_msi_vec_count);
880 static void pci_msi_shutdown(struct pci_dev *dev)
882 struct msi_desc *desc;
883 u32 mask;
885 if (!pci_msi_enable || !dev || !dev->msi_enabled)
886 return;
888 BUG_ON(list_empty(dev_to_msi_list(&dev->dev)));
889 desc = first_pci_msi_entry(dev);
891 pci_msi_set_enable(dev, 0);
892 pci_intx_for_msi(dev, 1);
893 dev->msi_enabled = 0;
895 /* Return the device with MSI unmasked as initial states */
896 mask = msi_mask(desc->msi_attrib.multi_cap);
897 /* Keep cached state to be restored */
898 __pci_msi_desc_mask_irq(desc, mask, ~mask);
900 /* Restore dev->irq to its default pin-assertion irq */
901 dev->irq = desc->msi_attrib.default_irq;
902 pcibios_alloc_irq(dev);
905 void pci_disable_msi(struct pci_dev *dev)
907 if (!pci_msi_enable || !dev || !dev->msi_enabled)
908 return;
910 pci_msi_shutdown(dev);
911 free_msi_irqs(dev);
913 EXPORT_SYMBOL(pci_disable_msi);
916 * pci_msix_vec_count - return the number of device's MSI-X table entries
917 * @dev: pointer to the pci_dev data structure of MSI-X device function
918 * This function returns the number of device's MSI-X table entries and
919 * therefore the number of MSI-X vectors device is capable of sending.
920 * It returns a negative errno if the device is not capable of sending MSI-X
921 * interrupts.
923 int pci_msix_vec_count(struct pci_dev *dev)
925 u16 control;
927 if (!dev->msix_cap)
928 return -EINVAL;
930 pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control);
931 return msix_table_size(control);
933 EXPORT_SYMBOL(pci_msix_vec_count);
935 static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries,
936 int nvec, const struct irq_affinity *affd)
938 int nr_entries;
939 int i, j;
941 if (!pci_msi_supported(dev, nvec))
942 return -EINVAL;
944 nr_entries = pci_msix_vec_count(dev);
945 if (nr_entries < 0)
946 return nr_entries;
947 if (nvec > nr_entries)
948 return nr_entries;
950 if (entries) {
951 /* Check for any invalid entries */
952 for (i = 0; i < nvec; i++) {
953 if (entries[i].entry >= nr_entries)
954 return -EINVAL; /* invalid entry */
955 for (j = i + 1; j < nvec; j++) {
956 if (entries[i].entry == entries[j].entry)
957 return -EINVAL; /* duplicate entry */
962 /* Check whether driver already requested for MSI irq */
963 if (dev->msi_enabled) {
964 pci_info(dev, "can't enable MSI-X (MSI IRQ already assigned)\n");
965 return -EINVAL;
967 return msix_capability_init(dev, entries, nvec, affd);
970 static void pci_msix_shutdown(struct pci_dev *dev)
972 struct msi_desc *entry;
974 if (!pci_msi_enable || !dev || !dev->msix_enabled)
975 return;
977 if (pci_dev_is_disconnected(dev)) {
978 dev->msix_enabled = 0;
979 return;
982 /* Return the device with MSI-X masked as initial states */
983 for_each_pci_msi_entry(entry, dev) {
984 /* Keep cached states to be restored */
985 __pci_msix_desc_mask_irq(entry, 1);
988 pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
989 pci_intx_for_msi(dev, 1);
990 dev->msix_enabled = 0;
991 pcibios_alloc_irq(dev);
994 void pci_disable_msix(struct pci_dev *dev)
996 if (!pci_msi_enable || !dev || !dev->msix_enabled)
997 return;
999 pci_msix_shutdown(dev);
1000 free_msi_irqs(dev);
1002 EXPORT_SYMBOL(pci_disable_msix);
1004 void pci_no_msi(void)
1006 pci_msi_enable = 0;
1010 * pci_msi_enabled - is MSI enabled?
1012 * Returns true if MSI has not been disabled by the command-line option
1013 * pci=nomsi.
1015 int pci_msi_enabled(void)
1017 return pci_msi_enable;
1019 EXPORT_SYMBOL(pci_msi_enabled);
1021 static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
1022 const struct irq_affinity *affd)
1024 int nvec;
1025 int rc;
1027 if (!pci_msi_supported(dev, minvec))
1028 return -EINVAL;
1030 /* Check whether driver already requested MSI-X irqs */
1031 if (dev->msix_enabled) {
1032 pci_info(dev, "can't enable MSI (MSI-X already enabled)\n");
1033 return -EINVAL;
1036 if (maxvec < minvec)
1037 return -ERANGE;
1039 if (WARN_ON_ONCE(dev->msi_enabled))
1040 return -EINVAL;
1042 nvec = pci_msi_vec_count(dev);
1043 if (nvec < 0)
1044 return nvec;
1045 if (nvec < minvec)
1046 return -ENOSPC;
1048 if (nvec > maxvec)
1049 nvec = maxvec;
1051 for (;;) {
1052 if (affd) {
1053 nvec = irq_calc_affinity_vectors(minvec, nvec, affd);
1054 if (nvec < minvec)
1055 return -ENOSPC;
1058 rc = msi_capability_init(dev, nvec, affd);
1059 if (rc == 0)
1060 return nvec;
1062 if (rc < 0)
1063 return rc;
1064 if (rc < minvec)
1065 return -ENOSPC;
1067 nvec = rc;
1071 /* deprecated, don't use */
1072 int pci_enable_msi(struct pci_dev *dev)
1074 int rc = __pci_enable_msi_range(dev, 1, 1, NULL);
1075 if (rc < 0)
1076 return rc;
1077 return 0;
1079 EXPORT_SYMBOL(pci_enable_msi);
1081 static int __pci_enable_msix_range(struct pci_dev *dev,
1082 struct msix_entry *entries, int minvec,
1083 int maxvec, const struct irq_affinity *affd)
1085 int rc, nvec = maxvec;
1087 if (maxvec < minvec)
1088 return -ERANGE;
1090 if (WARN_ON_ONCE(dev->msix_enabled))
1091 return -EINVAL;
1093 for (;;) {
1094 if (affd) {
1095 nvec = irq_calc_affinity_vectors(minvec, nvec, affd);
1096 if (nvec < minvec)
1097 return -ENOSPC;
1100 rc = __pci_enable_msix(dev, entries, nvec, affd);
1101 if (rc == 0)
1102 return nvec;
1104 if (rc < 0)
1105 return rc;
1106 if (rc < minvec)
1107 return -ENOSPC;
1109 nvec = rc;
1114 * pci_enable_msix_range - configure device's MSI-X capability structure
1115 * @dev: pointer to the pci_dev data structure of MSI-X device function
1116 * @entries: pointer to an array of MSI-X entries
1117 * @minvec: minimum number of MSI-X irqs requested
1118 * @maxvec: maximum number of MSI-X irqs requested
1120 * Setup the MSI-X capability structure of device function with a maximum
1121 * possible number of interrupts in the range between @minvec and @maxvec
1122 * upon its software driver call to request for MSI-X mode enabled on its
1123 * hardware device function. It returns a negative errno if an error occurs.
1124 * If it succeeds, it returns the actual number of interrupts allocated and
1125 * indicates the successful configuration of MSI-X capability structure
1126 * with new allocated MSI-X interrupts.
1128 int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,
1129 int minvec, int maxvec)
1131 return __pci_enable_msix_range(dev, entries, minvec, maxvec, NULL);
1133 EXPORT_SYMBOL(pci_enable_msix_range);
1136 * pci_alloc_irq_vectors_affinity - allocate multiple IRQs for a device
1137 * @dev: PCI device to operate on
1138 * @min_vecs: minimum number of vectors required (must be >= 1)
1139 * @max_vecs: maximum (desired) number of vectors
1140 * @flags: flags or quirks for the allocation
1141 * @affd: optional description of the affinity requirements
1143 * Allocate up to @max_vecs interrupt vectors for @dev, using MSI-X or MSI
1144 * vectors if available, and fall back to a single legacy vector
1145 * if neither is available. Return the number of vectors allocated,
1146 * (which might be smaller than @max_vecs) if successful, or a negative
1147 * error code on error. If less than @min_vecs interrupt vectors are
1148 * available for @dev the function will fail with -ENOSPC.
1150 * To get the Linux IRQ number used for a vector that can be passed to
1151 * request_irq() use the pci_irq_vector() helper.
1153 int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
1154 unsigned int max_vecs, unsigned int flags,
1155 const struct irq_affinity *affd)
1157 static const struct irq_affinity msi_default_affd;
1158 int msix_vecs = -ENOSPC;
1159 int msi_vecs = -ENOSPC;
1161 if (flags & PCI_IRQ_AFFINITY) {
1162 if (!affd)
1163 affd = &msi_default_affd;
1164 } else {
1165 if (WARN_ON(affd))
1166 affd = NULL;
1169 if (flags & PCI_IRQ_MSIX) {
1170 msix_vecs = __pci_enable_msix_range(dev, NULL, min_vecs,
1171 max_vecs, affd);
1172 if (msix_vecs > 0)
1173 return msix_vecs;
1176 if (flags & PCI_IRQ_MSI) {
1177 msi_vecs = __pci_enable_msi_range(dev, min_vecs, max_vecs,
1178 affd);
1179 if (msi_vecs > 0)
1180 return msi_vecs;
1183 /* use legacy irq if allowed */
1184 if (flags & PCI_IRQ_LEGACY) {
1185 if (min_vecs == 1 && dev->irq) {
1186 pci_intx(dev, 1);
1187 return 1;
1191 if (msix_vecs == -ENOSPC)
1192 return -ENOSPC;
1193 return msi_vecs;
1195 EXPORT_SYMBOL(pci_alloc_irq_vectors_affinity);
1198 * pci_free_irq_vectors - free previously allocated IRQs for a device
1199 * @dev: PCI device to operate on
1201 * Undoes the allocations and enabling in pci_alloc_irq_vectors().
1203 void pci_free_irq_vectors(struct pci_dev *dev)
1205 pci_disable_msix(dev);
1206 pci_disable_msi(dev);
1208 EXPORT_SYMBOL(pci_free_irq_vectors);
1211 * pci_irq_vector - return Linux IRQ number of a device vector
1212 * @dev: PCI device to operate on
1213 * @nr: device-relative interrupt vector index (0-based).
1215 int pci_irq_vector(struct pci_dev *dev, unsigned int nr)
1217 if (dev->msix_enabled) {
1218 struct msi_desc *entry;
1219 int i = 0;
1221 for_each_pci_msi_entry(entry, dev) {
1222 if (i == nr)
1223 return entry->irq;
1224 i++;
1226 WARN_ON_ONCE(1);
1227 return -EINVAL;
1230 if (dev->msi_enabled) {
1231 struct msi_desc *entry = first_pci_msi_entry(dev);
1233 if (WARN_ON_ONCE(nr >= entry->nvec_used))
1234 return -EINVAL;
1235 } else {
1236 if (WARN_ON_ONCE(nr > 0))
1237 return -EINVAL;
1240 return dev->irq + nr;
1242 EXPORT_SYMBOL(pci_irq_vector);
1245 * pci_irq_get_affinity - return the affinity of a particular msi vector
1246 * @dev: PCI device to operate on
1247 * @nr: device-relative interrupt vector index (0-based).
1249 const struct cpumask *pci_irq_get_affinity(struct pci_dev *dev, int nr)
1251 if (dev->msix_enabled) {
1252 struct msi_desc *entry;
1253 int i = 0;
1255 for_each_pci_msi_entry(entry, dev) {
1256 if (i == nr)
1257 return entry->affinity;
1258 i++;
1260 WARN_ON_ONCE(1);
1261 return NULL;
1262 } else if (dev->msi_enabled) {
1263 struct msi_desc *entry = first_pci_msi_entry(dev);
1265 if (WARN_ON_ONCE(!entry || !entry->affinity ||
1266 nr >= entry->nvec_used))
1267 return NULL;
1269 return &entry->affinity[nr];
1270 } else {
1271 return cpu_possible_mask;
1274 EXPORT_SYMBOL(pci_irq_get_affinity);
1277 * pci_irq_get_node - return the numa node of a particular msi vector
1278 * @pdev: PCI device to operate on
1279 * @vec: device-relative interrupt vector index (0-based).
1281 int pci_irq_get_node(struct pci_dev *pdev, int vec)
1283 const struct cpumask *mask;
1285 mask = pci_irq_get_affinity(pdev, vec);
1286 if (mask)
1287 return local_memory_node(cpu_to_node(cpumask_first(mask)));
1288 return dev_to_node(&pdev->dev);
1290 EXPORT_SYMBOL(pci_irq_get_node);
1292 struct pci_dev *msi_desc_to_pci_dev(struct msi_desc *desc)
1294 return to_pci_dev(desc->dev);
1296 EXPORT_SYMBOL(msi_desc_to_pci_dev);
1298 void *msi_desc_to_pci_sysdata(struct msi_desc *desc)
1300 struct pci_dev *dev = msi_desc_to_pci_dev(desc);
1302 return dev->bus->sysdata;
1304 EXPORT_SYMBOL_GPL(msi_desc_to_pci_sysdata);
1306 #ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
1308 * pci_msi_domain_write_msg - Helper to write MSI message to PCI config space
1309 * @irq_data: Pointer to interrupt data of the MSI interrupt
1310 * @msg: Pointer to the message
1312 void pci_msi_domain_write_msg(struct irq_data *irq_data, struct msi_msg *msg)
1314 struct msi_desc *desc = irq_data_get_msi_desc(irq_data);
1317 * For MSI-X desc->irq is always equal to irq_data->irq. For
1318 * MSI only the first interrupt of MULTI MSI passes the test.
1320 if (desc->irq == irq_data->irq)
1321 __pci_write_msi_msg(desc, msg);
1325 * pci_msi_domain_calc_hwirq - Generate a unique ID for an MSI source
1326 * @dev: Pointer to the PCI device
1327 * @desc: Pointer to the msi descriptor
1329 * The ID number is only used within the irqdomain.
1331 irq_hw_number_t pci_msi_domain_calc_hwirq(struct pci_dev *dev,
1332 struct msi_desc *desc)
1334 return (irq_hw_number_t)desc->msi_attrib.entry_nr |
1335 PCI_DEVID(dev->bus->number, dev->devfn) << 11 |
1336 (pci_domain_nr(dev->bus) & 0xFFFFFFFF) << 27;
1339 static inline bool pci_msi_desc_is_multi_msi(struct msi_desc *desc)
1341 return !desc->msi_attrib.is_msix && desc->nvec_used > 1;
1345 * pci_msi_domain_check_cap - Verify that @domain supports the capabilities for @dev
1346 * @domain: The interrupt domain to check
1347 * @info: The domain info for verification
1348 * @dev: The device to check
1350 * Returns:
1351 * 0 if the functionality is supported
1352 * 1 if Multi MSI is requested, but the domain does not support it
1353 * -ENOTSUPP otherwise
1355 int pci_msi_domain_check_cap(struct irq_domain *domain,
1356 struct msi_domain_info *info, struct device *dev)
1358 struct msi_desc *desc = first_pci_msi_entry(to_pci_dev(dev));
1360 /* Special handling to support __pci_enable_msi_range() */
1361 if (pci_msi_desc_is_multi_msi(desc) &&
1362 !(info->flags & MSI_FLAG_MULTI_PCI_MSI))
1363 return 1;
1364 else if (desc->msi_attrib.is_msix && !(info->flags & MSI_FLAG_PCI_MSIX))
1365 return -ENOTSUPP;
1367 return 0;
1370 static int pci_msi_domain_handle_error(struct irq_domain *domain,
1371 struct msi_desc *desc, int error)
1373 /* Special handling to support __pci_enable_msi_range() */
1374 if (pci_msi_desc_is_multi_msi(desc) && error == -ENOSPC)
1375 return 1;
1377 return error;
1380 #ifdef GENERIC_MSI_DOMAIN_OPS
1381 static void pci_msi_domain_set_desc(msi_alloc_info_t *arg,
1382 struct msi_desc *desc)
1384 arg->desc = desc;
1385 arg->hwirq = pci_msi_domain_calc_hwirq(msi_desc_to_pci_dev(desc),
1386 desc);
1388 #else
1389 #define pci_msi_domain_set_desc NULL
1390 #endif
1392 static struct msi_domain_ops pci_msi_domain_ops_default = {
1393 .set_desc = pci_msi_domain_set_desc,
1394 .msi_check = pci_msi_domain_check_cap,
1395 .handle_error = pci_msi_domain_handle_error,
1398 static void pci_msi_domain_update_dom_ops(struct msi_domain_info *info)
1400 struct msi_domain_ops *ops = info->ops;
1402 if (ops == NULL) {
1403 info->ops = &pci_msi_domain_ops_default;
1404 } else {
1405 if (ops->set_desc == NULL)
1406 ops->set_desc = pci_msi_domain_set_desc;
1407 if (ops->msi_check == NULL)
1408 ops->msi_check = pci_msi_domain_check_cap;
1409 if (ops->handle_error == NULL)
1410 ops->handle_error = pci_msi_domain_handle_error;
1414 static void pci_msi_domain_update_chip_ops(struct msi_domain_info *info)
1416 struct irq_chip *chip = info->chip;
1418 BUG_ON(!chip);
1419 if (!chip->irq_write_msi_msg)
1420 chip->irq_write_msi_msg = pci_msi_domain_write_msg;
1421 if (!chip->irq_mask)
1422 chip->irq_mask = pci_msi_mask_irq;
1423 if (!chip->irq_unmask)
1424 chip->irq_unmask = pci_msi_unmask_irq;
1428 * pci_msi_create_irq_domain - Create a MSI interrupt domain
1429 * @fwnode: Optional fwnode of the interrupt controller
1430 * @info: MSI domain info
1431 * @parent: Parent irq domain
1433 * Updates the domain and chip ops and creates a MSI interrupt domain.
1435 * Returns:
1436 * A domain pointer or NULL in case of failure.
1438 struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
1439 struct msi_domain_info *info,
1440 struct irq_domain *parent)
1442 struct irq_domain *domain;
1444 if (WARN_ON(info->flags & MSI_FLAG_LEVEL_CAPABLE))
1445 info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
1447 if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
1448 pci_msi_domain_update_dom_ops(info);
1449 if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
1450 pci_msi_domain_update_chip_ops(info);
1452 info->flags |= MSI_FLAG_ACTIVATE_EARLY;
1453 if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE))
1454 info->flags |= MSI_FLAG_MUST_REACTIVATE;
1456 /* PCI-MSI is oneshot-safe */
1457 info->chip->flags |= IRQCHIP_ONESHOT_SAFE;
1459 domain = msi_create_irq_domain(fwnode, info, parent);
1460 if (!domain)
1461 return NULL;
1463 irq_domain_update_bus_token(domain, DOMAIN_BUS_PCI_MSI);
1464 return domain;
1466 EXPORT_SYMBOL_GPL(pci_msi_create_irq_domain);
1469 * Users of the generic MSI infrastructure expect a device to have a single ID,
1470 * so with DMA aliases we have to pick the least-worst compromise. Devices with
1471 * DMA phantom functions tend to still emit MSIs from the real function number,
1472 * so we ignore those and only consider topological aliases where either the
1473 * alias device or RID appears on a different bus number. We also make the
1474 * reasonable assumption that bridges are walked in an upstream direction (so
1475 * the last one seen wins), and the much braver assumption that the most likely
1476 * case is that of PCI->PCIe so we should always use the alias RID. This echoes
1477 * the logic from intel_irq_remapping's set_msi_sid(), which presumably works
1478 * well enough in practice; in the face of the horrible PCIe<->PCI-X conditions
1479 * for taking ownership all we can really do is close our eyes and hope...
1481 static int get_msi_id_cb(struct pci_dev *pdev, u16 alias, void *data)
1483 u32 *pa = data;
1484 u8 bus = PCI_BUS_NUM(*pa);
1486 if (pdev->bus->number != bus || PCI_BUS_NUM(alias) != bus)
1487 *pa = alias;
1489 return 0;
1493 * pci_msi_domain_get_msi_rid - Get the MSI requester id (RID)
1494 * @domain: The interrupt domain
1495 * @pdev: The PCI device.
1497 * The RID for a device is formed from the alias, with a firmware
1498 * supplied mapping applied
1500 * Returns: The RID.
1502 u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
1504 struct device_node *of_node;
1505 u32 rid = PCI_DEVID(pdev->bus->number, pdev->devfn);
1507 pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
1509 of_node = irq_domain_get_of_node(domain);
1510 rid = of_node ? of_msi_map_rid(&pdev->dev, of_node, rid) :
1511 iort_msi_map_rid(&pdev->dev, rid);
1513 return rid;
1517 * pci_msi_get_device_domain - Get the MSI domain for a given PCI device
1518 * @pdev: The PCI device
1520 * Use the firmware data to find a device-specific MSI domain
1521 * (i.e. not one that is set as a default).
1523 * Returns: The corresponding MSI domain or NULL if none has been found.
1525 struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
1527 struct irq_domain *dom;
1528 u32 rid = PCI_DEVID(pdev->bus->number, pdev->devfn);
1530 pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
1531 dom = of_msi_map_get_device_domain(&pdev->dev, rid);
1532 if (!dom)
1533 dom = iort_get_device_domain(&pdev->dev, rid);
1534 return dom;
1536 #endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */