1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * PCI IRQ handling code
4 *
5 * Copyright (c) 2008 James Bottomley <James.Bottomley@HansenPartnership.com>
6 * Copyright (C) 2017 Christoph Hellwig.
7 */
8
9 #include <linux/acpi.h>
10 #include <linux/device.h>
11 #include <linux/kernel.h>
12 #include <linux/export.h>
13 #include <linux/pci.h>
14
15 static void pci_note_irq_problem(struct pci_dev *pdev, const char *reason)
16 {
17 struct pci_dev *parent = to_pci_dev(pdev->dev.parent);
18
19 pci_err(pdev, "Potentially misrouted IRQ (Bridge %s %04x:%04x)\n",
20 dev_name(&parent->dev), parent->vendor, parent->device);
21 pci_err(pdev, "%s\n", reason);
22 pci_err(pdev, "Please report to linux-kernel@vger.kernel.org\n");
23 WARN_ON(1);
24 }
25
26 /**
27 * pci_lost_interrupt - reports a lost PCI interrupt
28 * @pdev: device whose interrupt is lost
29 *
30 * The primary function of this routine is to report a lost interrupt
31 * in a standard way which users can recognise (instead of blaming the
32 * driver).
33 *
34 * Returns:
35 * a suggestion for fixing it (although the driver is not required to
36 * act on this).
37 */
38 enum pci_lost_interrupt_reason pci_lost_interrupt(struct pci_dev *pdev)
39 {
40 if (pdev->msi_enabled || pdev->msix_enabled) {
41 enum pci_lost_interrupt_reason ret;
42
43 if (pdev->msix_enabled) {
44 pci_note_irq_problem(pdev, "MSIX routing failure");
45 ret = PCI_LOST_IRQ_DISABLE_MSIX;
46 } else {
47 pci_note_irq_problem(pdev, "MSI routing failure");
48 ret = PCI_LOST_IRQ_DISABLE_MSI;
49 }
50 return ret;
51 }
52 #ifdef CONFIG_ACPI
53 if (!(acpi_disabled || acpi_noirq)) {
54 pci_note_irq_problem(pdev, "Potential ACPI misrouting please reboot with acpi=noirq");
55 /* currently no way to fix acpi on the fly */
56 return PCI_LOST_IRQ_DISABLE_ACPI;
57 }
58 #endif
59 pci_note_irq_problem(pdev, "unknown cause (not MSI or ACPI)");
60 return PCI_LOST_IRQ_NO_INFORMATION;
61 }
62 EXPORT_SYMBOL(pci_lost_interrupt);
63
64 /**
65 * pci_request_irq - allocate an interrupt line for a PCI device
66 * @dev: PCI device to operate on
67 * @nr: device-relative interrupt vector index (0-based).
68 * @handler: Function to be called when the IRQ occurs.
69 * Primary handler for threaded interrupts.
70 * If NULL and thread_fn != NULL the default primary handler is
71 * installed.
72 * @thread_fn: Function called from the IRQ handler thread
73 * If NULL, no IRQ thread is created
74 * @dev_id: Cookie passed back to the handler function
75 * @fmt: Printf-like format string naming the handler
76 *
77 * This call allocates interrupt resources and enables the interrupt line and
78 * IRQ handling. From the point this call is made @handler and @thread_fn may
79 * be invoked. All interrupts requested using this function might be shared.
80 *
81 * @dev_id must not be NULL and must be globally unique.
82 */
83 int pci_request_irq(struct pci_dev *dev, unsigned int nr, irq_handler_t handler,
84 irq_handler_t thread_fn, void *dev_id, const char *fmt, ...)
85 {
86 va_list ap;
87 int ret;
88 char *devname;
89 unsigned long irqflags = IRQF_SHARED;
90
91 if (!handler)
92 irqflags |= IRQF_ONESHOT;
93
94 va_start(ap, fmt);
95 devname = kvasprintf(GFP_KERNEL, fmt, ap);
96 va_end(ap);
97
98 ret = request_threaded_irq(pci_irq_vector(dev, nr), handler, thread_fn,
99 irqflags, devname, dev_id);
100 if (ret)
101 kfree(devname);
102 return ret;
103 }
104 EXPORT_SYMBOL(pci_request_irq);
105
106 /**
107 * pci_free_irq - free an interrupt allocated with pci_request_irq
108 * @dev: PCI device to operate on
109 * @nr: device-relative interrupt vector index (0-based).
110 * @dev_id: Device identity to free
111 *
112 * Remove an interrupt handler. The handler is removed and if the interrupt
113 * line is no longer in use by any driver it is disabled. The caller must
114 * ensure the interrupt is disabled on the device before calling this function.
115 * The function does not return until any executing interrupts for this IRQ
116 * have completed.
117 *
118 * This function must not be called from interrupt context.
119 */
120 void pci_free_irq(struct pci_dev *dev, unsigned int nr, void *dev_id)
121 {
122 kfree(free_irq(pci_irq_vector(dev, nr), dev_id));
123 }
124 EXPORT_SYMBOL(pci_free_irq);