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, ap); 46 va_end(ap); 47 if (!devname) 48 return -ENOMEM; 49 50 ret = request_threaded_irq(pci_irq_vector(dev, nr), handler, thread_fn, 51 irqflags, devname, dev_id); 52 if (ret) 53 kfree(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(free_irq(pci_irq_vector(dev, nr), dev_id)); 75 } 76 EXPORT_SYMBOL(pci_free_irq); 77