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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/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/slab.h>
23
24#include "pci.h"
25#include "msi.h"
26
27static int pci_msi_enable = 1;
28
29/* Arch hooks */
30
31#ifndef arch_msi_check_device
32int arch_msi_check_device(struct pci_dev *dev, int nvec, int type)
33{
34 return 0;
35}
36#endif
37
38#ifndef arch_setup_msi_irqs
39# define arch_setup_msi_irqs default_setup_msi_irqs
40# define HAVE_DEFAULT_MSI_SETUP_IRQS
41#endif
42
43#ifdef HAVE_DEFAULT_MSI_SETUP_IRQS
44int default_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
45{
46 struct msi_desc *entry;
47 int ret;
48
49 /*
50 * If an architecture wants to support multiple MSI, it needs to
51 * override arch_setup_msi_irqs()
52 */
53 if (type == PCI_CAP_ID_MSI && nvec > 1)
54 return 1;
55
56 list_for_each_entry(entry, &dev->msi_list, list) {
57 ret = arch_setup_msi_irq(dev, entry);
58 if (ret < 0)
59 return ret;
60 if (ret > 0)
61 return -ENOSPC;
62 }
63
64 return 0;
65}
66#endif
67
68#ifndef arch_teardown_msi_irqs
69# define arch_teardown_msi_irqs default_teardown_msi_irqs
70# define HAVE_DEFAULT_MSI_TEARDOWN_IRQS
71#endif
72
73#ifdef HAVE_DEFAULT_MSI_TEARDOWN_IRQS
74void default_teardown_msi_irqs(struct pci_dev *dev)
75{
76 struct msi_desc *entry;
77
78 list_for_each_entry(entry, &dev->msi_list, list) {
79 int i, nvec;
80 if (entry->irq == 0)
81 continue;
82 nvec = 1 << entry->msi_attrib.multiple;
83 for (i = 0; i < nvec; i++)
84 arch_teardown_msi_irq(entry->irq + i);
85 }
86}
87#endif
88
89#ifndef arch_restore_msi_irqs
90# define arch_restore_msi_irqs default_restore_msi_irqs
91# define HAVE_DEFAULT_MSI_RESTORE_IRQS
92#endif
93
94#ifdef HAVE_DEFAULT_MSI_RESTORE_IRQS
95void default_restore_msi_irqs(struct pci_dev *dev, int irq)
96{
97 struct msi_desc *entry;
98
99 entry = NULL;
100 if (dev->msix_enabled) {
101 list_for_each_entry(entry, &dev->msi_list, list) {
102 if (irq == entry->irq)
103 break;
104 }
105 } else if (dev->msi_enabled) {
106 entry = irq_get_msi_desc(irq);
107 }
108
109 if (entry)
110 write_msi_msg(irq, &entry->msg);
111}
112#endif
113
114static void msi_set_enable(struct pci_dev *dev, int pos, int enable)
115{
116 u16 control;
117
118 BUG_ON(!pos);
119
120 pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
121 control &= ~PCI_MSI_FLAGS_ENABLE;
122 if (enable)
123 control |= PCI_MSI_FLAGS_ENABLE;
124 pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
125}
126
127static void msix_set_enable(struct pci_dev *dev, int enable)
128{
129 int pos;
130 u16 control;
131
132 pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
133 if (pos) {
134 pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
135 control &= ~PCI_MSIX_FLAGS_ENABLE;
136 if (enable)
137 control |= PCI_MSIX_FLAGS_ENABLE;
138 pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
139 }
140}
141
142static inline __attribute_const__ u32 msi_mask(unsigned x)
143{
144 /* Don't shift by >= width of type */
145 if (x >= 5)
146 return 0xffffffff;
147 return (1 << (1 << x)) - 1;
148}
149
150static inline __attribute_const__ u32 msi_capable_mask(u16 control)
151{
152 return msi_mask((control >> 1) & 7);
153}
154
155static inline __attribute_const__ u32 msi_enabled_mask(u16 control)
156{
157 return msi_mask((control >> 4) & 7);
158}
159
160/*
161 * PCI 2.3 does not specify mask bits for each MSI interrupt. Attempting to
162 * mask all MSI interrupts by clearing the MSI enable bit does not work
163 * reliably as devices without an INTx disable bit will then generate a
164 * level IRQ which will never be cleared.
165 */
166static u32 __msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
167{
168 u32 mask_bits = desc->masked;
169
170 if (!desc->msi_attrib.maskbit)
171 return 0;
172
173 mask_bits &= ~mask;
174 mask_bits |= flag;
175 pci_write_config_dword(desc->dev, desc->mask_pos, mask_bits);
176
177 return mask_bits;
178}
179
180static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
181{
182 desc->masked = __msi_mask_irq(desc, mask, flag);
183}
184
185/*
186 * This internal function does not flush PCI writes to the device.
187 * All users must ensure that they read from the device before either
188 * assuming that the device state is up to date, or returning out of this
189 * file. This saves a few milliseconds when initialising devices with lots
190 * of MSI-X interrupts.
191 */
192static u32 __msix_mask_irq(struct msi_desc *desc, u32 flag)
193{
194 u32 mask_bits = desc->masked;
195 unsigned offset = desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
196 PCI_MSIX_ENTRY_VECTOR_CTRL;
197 mask_bits &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT;
198 if (flag)
199 mask_bits |= PCI_MSIX_ENTRY_CTRL_MASKBIT;
200 writel(mask_bits, desc->mask_base + offset);
201
202 return mask_bits;
203}
204
205static void msix_mask_irq(struct msi_desc *desc, u32 flag)
206{
207 desc->masked = __msix_mask_irq(desc, flag);
208}
209
210static void msi_set_mask_bit(struct irq_data *data, u32 flag)
211{
212 struct msi_desc *desc = irq_data_get_msi(data);
213
214 if (desc->msi_attrib.is_msix) {
215 msix_mask_irq(desc, flag);
216 readl(desc->mask_base); /* Flush write to device */
217 } else {
218 unsigned offset = data->irq - desc->dev->irq;
219 msi_mask_irq(desc, 1 << offset, flag << offset);
220 }
221}
222
223void mask_msi_irq(struct irq_data *data)
224{
225 msi_set_mask_bit(data, 1);
226}
227
228void unmask_msi_irq(struct irq_data *data)
229{
230 msi_set_mask_bit(data, 0);
231}
232
233void __read_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
234{
235 BUG_ON(entry->dev->current_state != PCI_D0);
236
237 if (entry->msi_attrib.is_msix) {
238 void __iomem *base = entry->mask_base +
239 entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
240
241 msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR);
242 msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR);
243 msg->data = readl(base + PCI_MSIX_ENTRY_DATA);
244 } else {
245 struct pci_dev *dev = entry->dev;
246 int pos = entry->msi_attrib.pos;
247 u16 data;
248
249 pci_read_config_dword(dev, msi_lower_address_reg(pos),
250 &msg->address_lo);
251 if (entry->msi_attrib.is_64) {
252 pci_read_config_dword(dev, msi_upper_address_reg(pos),
253 &msg->address_hi);
254 pci_read_config_word(dev, msi_data_reg(pos, 1), &data);
255 } else {
256 msg->address_hi = 0;
257 pci_read_config_word(dev, msi_data_reg(pos, 0), &data);
258 }
259 msg->data = data;
260 }
261}
262
263void read_msi_msg(unsigned int irq, struct msi_msg *msg)
264{
265 struct msi_desc *entry = irq_get_msi_desc(irq);
266
267 __read_msi_msg(entry, msg);
268}
269
270void __get_cached_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
271{
272 /* Assert that the cache is valid, assuming that
273 * valid messages are not all-zeroes. */
274 BUG_ON(!(entry->msg.address_hi | entry->msg.address_lo |
275 entry->msg.data));
276
277 *msg = entry->msg;
278}
279
280void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg)
281{
282 struct msi_desc *entry = irq_get_msi_desc(irq);
283
284 __get_cached_msi_msg(entry, msg);
285}
286
287void __write_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
288{
289 if (entry->dev->current_state != PCI_D0) {
290 /* Don't touch the hardware now */
291 } else if (entry->msi_attrib.is_msix) {
292 void __iomem *base;
293 base = entry->mask_base +
294 entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
295
296 writel(msg->address_lo, base + PCI_MSIX_ENTRY_LOWER_ADDR);
297 writel(msg->address_hi, base + PCI_MSIX_ENTRY_UPPER_ADDR);
298 writel(msg->data, base + PCI_MSIX_ENTRY_DATA);
299 } else {
300 struct pci_dev *dev = entry->dev;
301 int pos = entry->msi_attrib.pos;
302 u16 msgctl;
303
304 pci_read_config_word(dev, msi_control_reg(pos), &msgctl);
305 msgctl &= ~PCI_MSI_FLAGS_QSIZE;
306 msgctl |= entry->msi_attrib.multiple << 4;
307 pci_write_config_word(dev, msi_control_reg(pos), msgctl);
308
309 pci_write_config_dword(dev, msi_lower_address_reg(pos),
310 msg->address_lo);
311 if (entry->msi_attrib.is_64) {
312 pci_write_config_dword(dev, msi_upper_address_reg(pos),
313 msg->address_hi);
314 pci_write_config_word(dev, msi_data_reg(pos, 1),
315 msg->data);
316 } else {
317 pci_write_config_word(dev, msi_data_reg(pos, 0),
318 msg->data);
319 }
320 }
321 entry->msg = *msg;
322}
323
324void write_msi_msg(unsigned int irq, struct msi_msg *msg)
325{
326 struct msi_desc *entry = irq_get_msi_desc(irq);
327
328 __write_msi_msg(entry, msg);
329}
330
331static void free_msi_irqs(struct pci_dev *dev)
332{
333 struct msi_desc *entry, *tmp;
334
335 list_for_each_entry(entry, &dev->msi_list, list) {
336 int i, nvec;
337 if (!entry->irq)
338 continue;
339 nvec = 1 << entry->msi_attrib.multiple;
340 for (i = 0; i < nvec; i++)
341 BUG_ON(irq_has_action(entry->irq + i));
342 }
343
344 arch_teardown_msi_irqs(dev);
345
346 list_for_each_entry_safe(entry, tmp, &dev->msi_list, list) {
347 if (entry->msi_attrib.is_msix) {
348 if (list_is_last(&entry->list, &dev->msi_list))
349 iounmap(entry->mask_base);
350 }
351
352 /*
353 * Its possible that we get into this path
354 * When populate_msi_sysfs fails, which means the entries
355 * were not registered with sysfs. In that case don't
356 * unregister them.
357 */
358 if (entry->kobj.parent) {
359 kobject_del(&entry->kobj);
360 kobject_put(&entry->kobj);
361 }
362
363 list_del(&entry->list);
364 kfree(entry);
365 }
366}
367
368static struct msi_desc *alloc_msi_entry(struct pci_dev *dev)
369{
370 struct msi_desc *desc = kzalloc(sizeof(*desc), GFP_KERNEL);
371 if (!desc)
372 return NULL;
373
374 INIT_LIST_HEAD(&desc->list);
375 desc->dev = dev;
376
377 return desc;
378}
379
380static void pci_intx_for_msi(struct pci_dev *dev, int enable)
381{
382 if (!(dev->dev_flags & PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG))
383 pci_intx(dev, enable);
384}
385
386static void __pci_restore_msi_state(struct pci_dev *dev)
387{
388 int pos;
389 u16 control;
390 struct msi_desc *entry;
391
392 if (!dev->msi_enabled)
393 return;
394
395 entry = irq_get_msi_desc(dev->irq);
396 pos = entry->msi_attrib.pos;
397
398 pci_intx_for_msi(dev, 0);
399 msi_set_enable(dev, pos, 0);
400 arch_restore_msi_irqs(dev, dev->irq);
401
402 pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
403 msi_mask_irq(entry, msi_capable_mask(control), entry->masked);
404 control &= ~PCI_MSI_FLAGS_QSIZE;
405 control |= (entry->msi_attrib.multiple << 4) | PCI_MSI_FLAGS_ENABLE;
406 pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
407}
408
409static void __pci_restore_msix_state(struct pci_dev *dev)
410{
411 int pos;
412 struct msi_desc *entry;
413 u16 control;
414
415 if (!dev->msix_enabled)
416 return;
417 BUG_ON(list_empty(&dev->msi_list));
418 entry = list_first_entry(&dev->msi_list, struct msi_desc, list);
419 pos = entry->msi_attrib.pos;
420 pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
421
422 /* route the table */
423 pci_intx_for_msi(dev, 0);
424 control |= PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL;
425 pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
426
427 list_for_each_entry(entry, &dev->msi_list, list) {
428 arch_restore_msi_irqs(dev, entry->irq);
429 msix_mask_irq(entry, entry->masked);
430 }
431
432 control &= ~PCI_MSIX_FLAGS_MASKALL;
433 pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
434}
435
436void pci_restore_msi_state(struct pci_dev *dev)
437{
438 __pci_restore_msi_state(dev);
439 __pci_restore_msix_state(dev);
440}
441EXPORT_SYMBOL_GPL(pci_restore_msi_state);
442
443
444#define to_msi_attr(obj) container_of(obj, struct msi_attribute, attr)
445#define to_msi_desc(obj) container_of(obj, struct msi_desc, kobj)
446
447struct msi_attribute {
448 struct attribute attr;
449 ssize_t (*show)(struct msi_desc *entry, struct msi_attribute *attr,
450 char *buf);
451 ssize_t (*store)(struct msi_desc *entry, struct msi_attribute *attr,
452 const char *buf, size_t count);
453};
454
455static ssize_t show_msi_mode(struct msi_desc *entry, struct msi_attribute *atr,
456 char *buf)
457{
458 return sprintf(buf, "%s\n", entry->msi_attrib.is_msix ? "msix" : "msi");
459}
460
461static ssize_t msi_irq_attr_show(struct kobject *kobj,
462 struct attribute *attr, char *buf)
463{
464 struct msi_attribute *attribute = to_msi_attr(attr);
465 struct msi_desc *entry = to_msi_desc(kobj);
466
467 if (!attribute->show)
468 return -EIO;
469
470 return attribute->show(entry, attribute, buf);
471}
472
473static const struct sysfs_ops msi_irq_sysfs_ops = {
474 .show = msi_irq_attr_show,
475};
476
477static struct msi_attribute mode_attribute =
478 __ATTR(mode, S_IRUGO, show_msi_mode, NULL);
479
480
481struct attribute *msi_irq_default_attrs[] = {
482 &mode_attribute.attr,
483 NULL
484};
485
486void msi_kobj_release(struct kobject *kobj)
487{
488 struct msi_desc *entry = to_msi_desc(kobj);
489
490 pci_dev_put(entry->dev);
491}
492
493static struct kobj_type msi_irq_ktype = {
494 .release = msi_kobj_release,
495 .sysfs_ops = &msi_irq_sysfs_ops,
496 .default_attrs = msi_irq_default_attrs,
497};
498
499static int populate_msi_sysfs(struct pci_dev *pdev)
500{
501 struct msi_desc *entry;
502 struct kobject *kobj;
503 int ret;
504 int count = 0;
505
506 pdev->msi_kset = kset_create_and_add("msi_irqs", NULL, &pdev->dev.kobj);
507 if (!pdev->msi_kset)
508 return -ENOMEM;
509
510 list_for_each_entry(entry, &pdev->msi_list, list) {
511 kobj = &entry->kobj;
512 kobj->kset = pdev->msi_kset;
513 pci_dev_get(pdev);
514 ret = kobject_init_and_add(kobj, &msi_irq_ktype, NULL,
515 "%u", entry->irq);
516 if (ret)
517 goto out_unroll;
518
519 count++;
520 }
521
522 return 0;
523
524out_unroll:
525 list_for_each_entry(entry, &pdev->msi_list, list) {
526 if (!count)
527 break;
528 kobject_del(&entry->kobj);
529 kobject_put(&entry->kobj);
530 count--;
531 }
532 return ret;
533}
534
535/**
536 * msi_capability_init - configure device's MSI capability structure
537 * @dev: pointer to the pci_dev data structure of MSI device function
538 * @nvec: number of interrupts to allocate
539 *
540 * Setup the MSI capability structure of the device with the requested
541 * number of interrupts. A return value of zero indicates the successful
542 * setup of an entry with the new MSI irq. A negative return value indicates
543 * an error, and a positive return value indicates the number of interrupts
544 * which could have been allocated.
545 */
546static int msi_capability_init(struct pci_dev *dev, int nvec)
547{
548 struct msi_desc *entry;
549 int pos, ret;
550 u16 control;
551 unsigned mask;
552
553 pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
554 msi_set_enable(dev, pos, 0); /* Disable MSI during set up */
555
556 pci_read_config_word(dev, msi_control_reg(pos), &control);
557 /* MSI Entry Initialization */
558 entry = alloc_msi_entry(dev);
559 if (!entry)
560 return -ENOMEM;
561
562 entry->msi_attrib.is_msix = 0;
563 entry->msi_attrib.is_64 = is_64bit_address(control);
564 entry->msi_attrib.entry_nr = 0;
565 entry->msi_attrib.maskbit = is_mask_bit_support(control);
566 entry->msi_attrib.default_irq = dev->irq; /* Save IOAPIC IRQ */
567 entry->msi_attrib.pos = pos;
568
569 entry->mask_pos = msi_mask_reg(pos, entry->msi_attrib.is_64);
570 /* All MSIs are unmasked by default, Mask them all */
571 if (entry->msi_attrib.maskbit)
572 pci_read_config_dword(dev, entry->mask_pos, &entry->masked);
573 mask = msi_capable_mask(control);
574 msi_mask_irq(entry, mask, mask);
575
576 list_add_tail(&entry->list, &dev->msi_list);
577
578 /* Configure MSI capability structure */
579 ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI);
580 if (ret) {
581 msi_mask_irq(entry, mask, ~mask);
582 free_msi_irqs(dev);
583 return ret;
584 }
585
586 ret = populate_msi_sysfs(dev);
587 if (ret) {
588 msi_mask_irq(entry, mask, ~mask);
589 free_msi_irqs(dev);
590 return ret;
591 }
592
593 /* Set MSI enabled bits */
594 pci_intx_for_msi(dev, 0);
595 msi_set_enable(dev, pos, 1);
596 dev->msi_enabled = 1;
597
598 dev->irq = entry->irq;
599 return 0;
600}
601
602static void __iomem *msix_map_region(struct pci_dev *dev, unsigned pos,
603 unsigned nr_entries)
604{
605 resource_size_t phys_addr;
606 u32 table_offset;
607 u8 bir;
608
609 pci_read_config_dword(dev, msix_table_offset_reg(pos), &table_offset);
610 bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
611 table_offset &= ~PCI_MSIX_FLAGS_BIRMASK;
612 phys_addr = pci_resource_start(dev, bir) + table_offset;
613
614 return ioremap_nocache(phys_addr, nr_entries * PCI_MSIX_ENTRY_SIZE);
615}
616
617static int msix_setup_entries(struct pci_dev *dev, unsigned pos,
618 void __iomem *base, struct msix_entry *entries,
619 int nvec)
620{
621 struct msi_desc *entry;
622 int i;
623
624 for (i = 0; i < nvec; i++) {
625 entry = alloc_msi_entry(dev);
626 if (!entry) {
627 if (!i)
628 iounmap(base);
629 else
630 free_msi_irqs(dev);
631 /* No enough memory. Don't try again */
632 return -ENOMEM;
633 }
634
635 entry->msi_attrib.is_msix = 1;
636 entry->msi_attrib.is_64 = 1;
637 entry->msi_attrib.entry_nr = entries[i].entry;
638 entry->msi_attrib.default_irq = dev->irq;
639 entry->msi_attrib.pos = pos;
640 entry->mask_base = base;
641
642 list_add_tail(&entry->list, &dev->msi_list);
643 }
644
645 return 0;
646}
647
648static void msix_program_entries(struct pci_dev *dev,
649 struct msix_entry *entries)
650{
651 struct msi_desc *entry;
652 int i = 0;
653
654 list_for_each_entry(entry, &dev->msi_list, list) {
655 int offset = entries[i].entry * PCI_MSIX_ENTRY_SIZE +
656 PCI_MSIX_ENTRY_VECTOR_CTRL;
657
658 entries[i].vector = entry->irq;
659 irq_set_msi_desc(entry->irq, entry);
660 entry->masked = readl(entry->mask_base + offset);
661 msix_mask_irq(entry, 1);
662 i++;
663 }
664}
665
666/**
667 * msix_capability_init - configure device's MSI-X capability
668 * @dev: pointer to the pci_dev data structure of MSI-X device function
669 * @entries: pointer to an array of struct msix_entry entries
670 * @nvec: number of @entries
671 *
672 * Setup the MSI-X capability structure of device function with a
673 * single MSI-X irq. A return of zero indicates the successful setup of
674 * requested MSI-X entries with allocated irqs or non-zero for otherwise.
675 **/
676static int msix_capability_init(struct pci_dev *dev,
677 struct msix_entry *entries, int nvec)
678{
679 int pos, ret;
680 u16 control;
681 void __iomem *base;
682
683 pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
684 pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
685
686 /* Ensure MSI-X is disabled while it is set up */
687 control &= ~PCI_MSIX_FLAGS_ENABLE;
688 pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
689
690 /* Request & Map MSI-X table region */
691 base = msix_map_region(dev, pos, multi_msix_capable(control));
692 if (!base)
693 return -ENOMEM;
694
695 ret = msix_setup_entries(dev, pos, base, entries, nvec);
696 if (ret)
697 return ret;
698
699 ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
700 if (ret)
701 goto error;
702
703 /*
704 * Some devices require MSI-X to be enabled before we can touch the
705 * MSI-X registers. We need to mask all the vectors to prevent
706 * interrupts coming in before they're fully set up.
707 */
708 control |= PCI_MSIX_FLAGS_MASKALL | PCI_MSIX_FLAGS_ENABLE;
709 pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
710
711 msix_program_entries(dev, entries);
712
713 ret = populate_msi_sysfs(dev);
714 if (ret) {
715 ret = 0;
716 goto error;
717 }
718
719 /* Set MSI-X enabled bits and unmask the function */
720 pci_intx_for_msi(dev, 0);
721 dev->msix_enabled = 1;
722
723 control &= ~PCI_MSIX_FLAGS_MASKALL;
724 pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
725
726 return 0;
727
728error:
729 if (ret < 0) {
730 /*
731 * If we had some success, report the number of irqs
732 * we succeeded in setting up.
733 */
734 struct msi_desc *entry;
735 int avail = 0;
736
737 list_for_each_entry(entry, &dev->msi_list, list) {
738 if (entry->irq != 0)
739 avail++;
740 }
741 if (avail != 0)
742 ret = avail;
743 }
744
745 free_msi_irqs(dev);
746
747 return ret;
748}
749
750/**
751 * pci_msi_check_device - check whether MSI may be enabled on a device
752 * @dev: pointer to the pci_dev data structure of MSI device function
753 * @nvec: how many MSIs have been requested ?
754 * @type: are we checking for MSI or MSI-X ?
755 *
756 * Look at global flags, the device itself, and its parent busses
757 * to determine if MSI/-X are supported for the device. If MSI/-X is
758 * supported return 0, else return an error code.
759 **/
760static int pci_msi_check_device(struct pci_dev *dev, int nvec, int type)
761{
762 struct pci_bus *bus;
763 int ret;
764
765 /* MSI must be globally enabled and supported by the device */
766 if (!pci_msi_enable || !dev || dev->no_msi)
767 return -EINVAL;
768
769 /*
770 * You can't ask to have 0 or less MSIs configured.
771 * a) it's stupid ..
772 * b) the list manipulation code assumes nvec >= 1.
773 */
774 if (nvec < 1)
775 return -ERANGE;
776
777 /*
778 * Any bridge which does NOT route MSI transactions from its
779 * secondary bus to its primary bus must set NO_MSI flag on
780 * the secondary pci_bus.
781 * We expect only arch-specific PCI host bus controller driver
782 * or quirks for specific PCI bridges to be setting NO_MSI.
783 */
784 for (bus = dev->bus; bus; bus = bus->parent)
785 if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
786 return -EINVAL;
787
788 ret = arch_msi_check_device(dev, nvec, type);
789 if (ret)
790 return ret;
791
792 if (!pci_find_capability(dev, type))
793 return -EINVAL;
794
795 return 0;
796}
797
798/**
799 * pci_enable_msi_block - configure device's MSI capability structure
800 * @dev: device to configure
801 * @nvec: number of interrupts to configure
802 *
803 * Allocate IRQs for a device with the MSI capability.
804 * This function returns a negative errno if an error occurs. If it
805 * is unable to allocate the number of interrupts requested, it returns
806 * the number of interrupts it might be able to allocate. If it successfully
807 * allocates at least the number of interrupts requested, it returns 0 and
808 * updates the @dev's irq member to the lowest new interrupt number; the
809 * other interrupt numbers allocated to this device are consecutive.
810 */
811int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec)
812{
813 int status, pos, maxvec;
814 u16 msgctl;
815
816 pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
817 if (!pos)
818 return -EINVAL;
819 pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl);
820 maxvec = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
821 if (nvec > maxvec)
822 return maxvec;
823
824 status = pci_msi_check_device(dev, nvec, PCI_CAP_ID_MSI);
825 if (status)
826 return status;
827
828 WARN_ON(!!dev->msi_enabled);
829
830 /* Check whether driver already requested MSI-X irqs */
831 if (dev->msix_enabled) {
832 dev_info(&dev->dev, "can't enable MSI "
833 "(MSI-X already enabled)\n");
834 return -EINVAL;
835 }
836
837 status = msi_capability_init(dev, nvec);
838 return status;
839}
840EXPORT_SYMBOL(pci_enable_msi_block);
841
842void pci_msi_shutdown(struct pci_dev *dev)
843{
844 struct msi_desc *desc;
845 u32 mask;
846 u16 ctrl;
847 unsigned pos;
848
849 if (!pci_msi_enable || !dev || !dev->msi_enabled)
850 return;
851
852 BUG_ON(list_empty(&dev->msi_list));
853 desc = list_first_entry(&dev->msi_list, struct msi_desc, list);
854 pos = desc->msi_attrib.pos;
855
856 msi_set_enable(dev, pos, 0);
857 pci_intx_for_msi(dev, 1);
858 dev->msi_enabled = 0;
859
860 /* Return the device with MSI unmasked as initial states */
861 pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &ctrl);
862 mask = msi_capable_mask(ctrl);
863 /* Keep cached state to be restored */
864 __msi_mask_irq(desc, mask, ~mask);
865
866 /* Restore dev->irq to its default pin-assertion irq */
867 dev->irq = desc->msi_attrib.default_irq;
868}
869
870void pci_disable_msi(struct pci_dev *dev)
871{
872 if (!pci_msi_enable || !dev || !dev->msi_enabled)
873 return;
874
875 pci_msi_shutdown(dev);
876 free_msi_irqs(dev);
877 kset_unregister(dev->msi_kset);
878 dev->msi_kset = NULL;
879}
880EXPORT_SYMBOL(pci_disable_msi);
881
882/**
883 * pci_msix_table_size - return the number of device's MSI-X table entries
884 * @dev: pointer to the pci_dev data structure of MSI-X device function
885 */
886int pci_msix_table_size(struct pci_dev *dev)
887{
888 int pos;
889 u16 control;
890
891 pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
892 if (!pos)
893 return 0;
894
895 pci_read_config_word(dev, msi_control_reg(pos), &control);
896 return multi_msix_capable(control);
897}
898
899/**
900 * pci_enable_msix - configure device's MSI-X capability structure
901 * @dev: pointer to the pci_dev data structure of MSI-X device function
902 * @entries: pointer to an array of MSI-X entries
903 * @nvec: number of MSI-X irqs requested for allocation by device driver
904 *
905 * Setup the MSI-X capability structure of device function with the number
906 * of requested irqs upon its software driver call to request for
907 * MSI-X mode enabled on its hardware device function. A return of zero
908 * indicates the successful configuration of MSI-X capability structure
909 * with new allocated MSI-X irqs. A return of < 0 indicates a failure.
910 * Or a return of > 0 indicates that driver request is exceeding the number
911 * of irqs or MSI-X vectors available. Driver should use the returned value to
912 * re-send its request.
913 **/
914int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec)
915{
916 int status, nr_entries;
917 int i, j;
918
919 if (!entries)
920 return -EINVAL;
921
922 status = pci_msi_check_device(dev, nvec, PCI_CAP_ID_MSIX);
923 if (status)
924 return status;
925
926 nr_entries = pci_msix_table_size(dev);
927 if (nvec > nr_entries)
928 return nr_entries;
929
930 /* Check for any invalid entries */
931 for (i = 0; i < nvec; i++) {
932 if (entries[i].entry >= nr_entries)
933 return -EINVAL; /* invalid entry */
934 for (j = i + 1; j < nvec; j++) {
935 if (entries[i].entry == entries[j].entry)
936 return -EINVAL; /* duplicate entry */
937 }
938 }
939 WARN_ON(!!dev->msix_enabled);
940
941 /* Check whether driver already requested for MSI irq */
942 if (dev->msi_enabled) {
943 dev_info(&dev->dev, "can't enable MSI-X "
944 "(MSI IRQ already assigned)\n");
945 return -EINVAL;
946 }
947 status = msix_capability_init(dev, entries, nvec);
948 return status;
949}
950EXPORT_SYMBOL(pci_enable_msix);
951
952void pci_msix_shutdown(struct pci_dev *dev)
953{
954 struct msi_desc *entry;
955
956 if (!pci_msi_enable || !dev || !dev->msix_enabled)
957 return;
958
959 /* Return the device with MSI-X masked as initial states */
960 list_for_each_entry(entry, &dev->msi_list, list) {
961 /* Keep cached states to be restored */
962 __msix_mask_irq(entry, 1);
963 }
964
965 msix_set_enable(dev, 0);
966 pci_intx_for_msi(dev, 1);
967 dev->msix_enabled = 0;
968}
969
970void pci_disable_msix(struct pci_dev *dev)
971{
972 if (!pci_msi_enable || !dev || !dev->msix_enabled)
973 return;
974
975 pci_msix_shutdown(dev);
976 free_msi_irqs(dev);
977 kset_unregister(dev->msi_kset);
978 dev->msi_kset = NULL;
979}
980EXPORT_SYMBOL(pci_disable_msix);
981
982/**
983 * msi_remove_pci_irq_vectors - reclaim MSI(X) irqs to unused state
984 * @dev: pointer to the pci_dev data structure of MSI(X) device function
985 *
986 * Being called during hotplug remove, from which the device function
987 * is hot-removed. All previous assigned MSI/MSI-X irqs, if
988 * allocated for this device function, are reclaimed to unused state,
989 * which may be used later on.
990 **/
991void msi_remove_pci_irq_vectors(struct pci_dev *dev)
992{
993 if (!pci_msi_enable || !dev)
994 return;
995
996 if (dev->msi_enabled || dev->msix_enabled)
997 free_msi_irqs(dev);
998}
999
1000void pci_no_msi(void)
1001{
1002 pci_msi_enable = 0;
1003}
1004
1005/**
1006 * pci_msi_enabled - is MSI enabled?
1007 *
1008 * Returns true if MSI has not been disabled by the command-line option
1009 * pci=nomsi.
1010 **/
1011int pci_msi_enabled(void)
1012{
1013 return pci_msi_enable;
1014}
1015EXPORT_SYMBOL(pci_msi_enabled);
1016
1017void pci_msi_init_pci_dev(struct pci_dev *dev)
1018{
1019 int pos;
1020 INIT_LIST_HEAD(&dev->msi_list);
1021
1022 /* Disable the msi hardware to avoid screaming interrupts
1023 * during boot. This is the power on reset default so
1024 * usually this should be a noop.
1025 */
1026 pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
1027 if (pos)
1028 msi_set_enable(dev, pos, 0);
1029 msix_set_enable(dev, 0);
1030}