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/device.h> |
10 | #include <linux/kernel.h> |
11 | #include <linux/export.h> |
12 | #include <linux/pci.h> |
13 | |
14 | /** |
15 | * pci_request_irq - allocate an interrupt line for a PCI device |
16 | * @dev: PCI device to operate on |
17 | * @nr: device-relative interrupt vector index (0-based). |
18 | * @handler: Function to be called when the IRQ occurs. |
19 | * Primary handler for threaded interrupts. |
20 | * If NULL and thread_fn != NULL the default primary handler is |
21 | * installed. |
22 | * @thread_fn: Function called from the IRQ handler thread |
23 | * If NULL, no IRQ thread is created |
24 | * @dev_id: Cookie passed back to the handler function |
25 | * @fmt: Printf-like format string naming the handler |
26 | * |
27 | * This call allocates interrupt resources and enables the interrupt line and |
28 | * IRQ handling. From the point this call is made @handler and @thread_fn may |
29 | * be invoked. All interrupts requested using this function might be shared. |
30 | * |
31 | * @dev_id must not be NULL and must be globally unique. |
32 | */ |
33 | int pci_request_irq(struct pci_dev *dev, unsigned int nr, irq_handler_t handler, |
34 | irq_handler_t thread_fn, void *dev_id, const char *fmt, ...) |
35 | { |
36 | va_list ap; |
37 | int ret; |
38 | char *devname; |
39 | unsigned long irqflags = IRQF_SHARED; |
40 | |
41 | if (!handler) |
42 | irqflags |= IRQF_ONESHOT; |
43 | |
44 | va_start(ap, fmt); |
45 | devname = kvasprintf(GFP_KERNEL, fmt, args: ap); |
46 | va_end(ap); |
47 | if (!devname) |
48 | return -ENOMEM; |
49 | |
50 | ret = request_threaded_irq(irq: pci_irq_vector(dev, nr), handler, thread_fn, |
51 | flags: irqflags, name: devname, dev: dev_id); |
52 | if (ret) |
53 | kfree(objp: devname); |
54 | return ret; |
55 | } |
56 | EXPORT_SYMBOL(pci_request_irq); |
57 | |
58 | /** |
59 | * pci_free_irq - free an interrupt allocated with pci_request_irq |
60 | * @dev: PCI device to operate on |
61 | * @nr: device-relative interrupt vector index (0-based). |
62 | * @dev_id: Device identity to free |
63 | * |
64 | * Remove an interrupt handler. The handler is removed and if the interrupt |
65 | * line is no longer in use by any driver it is disabled. The caller must |
66 | * ensure the interrupt is disabled on the device before calling this function. |
67 | * The function does not return until any executing interrupts for this IRQ |
68 | * have completed. |
69 | * |
70 | * This function must not be called from interrupt context. |
71 | */ |
72 | void pci_free_irq(struct pci_dev *dev, unsigned int nr, void *dev_id) |
73 | { |
74 | kfree(objp: free_irq(pci_irq_vector(dev, nr), dev_id)); |
75 | } |
76 | EXPORT_SYMBOL(pci_free_irq); |
77 | |