Commit 704e8953 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Bjorn Helgaas
Browse files

PCI/irq: Add pci_request_irq() and pci_free_irq() helpers 



These are small wrappers around request_threaded_irq() and free_irq(),
which dynamically allocate space for the device name so that drivers don't
need to keep static buffers for these around.  Additionally it works with
device-relative vector numbers to make the usage easier, and force the
IRQF_SHARED flag on given that it has no runtime overhead and should be
supported by all PCI devices.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 25ce4be7

drivers/pci/irq.c

+60 −1
Original line number Diff line number Diff line 
/*

 * PCI IRQ failure handing code

 * PCI IRQ handling code

 *

 * Copyright (c) 2008 James Bottomley <James.Bottomley@HansenPartnership.com>

 * Copyright (C) 2017 Christoph Hellwig.

 */



#include <linux/acpi.h>
@@ -59,3 +60,61 @@ enum pci_lost_interrupt_reason pci_lost_interrupt(struct pci_dev *pdev) 
	return PCI_LOST_IRQ_NO_INFORMATION;

}

EXPORT_SYMBOL(pci_lost_interrupt);



/**

 * pci_request_irq - allocate an interrupt line for a PCI device

 * @dev:	PCI device to operate on

 * @nr:		device-relative interrupt vector index (0-based).

 * @handler:	Function to be called when the IRQ occurs.

 *		Primary handler for threaded interrupts.

 *		If NULL and thread_fn != NULL the default primary handler is

 *		installed.

 * @thread_fn:	Function called from the IRQ handler thread

 *		If NULL, no IRQ thread is created

 * @dev_id:	Cookie passed back to the handler function

 * @fmt:	Printf-like format string naming the handler

 *

 * This call allocates interrupt resources and enables the interrupt line and

 * IRQ handling. From the point this call is made @handler and @thread_fn may

 * be invoked.  All interrupts requested using this function might be shared.

 *

 * @dev_id must not be NULL and must be globally unique.

 */

int pci_request_irq(struct pci_dev *dev, unsigned int nr, irq_handler_t handler,

		irq_handler_t thread_fn, void *dev_id, const char *fmt, ...)

{

	va_list ap;

	int ret;

	char *devname;



	va_start(ap, fmt);

	devname = kvasprintf(GFP_KERNEL, fmt, ap);

	va_end(ap);



	ret = request_threaded_irq(pci_irq_vector(dev, nr), handler, thread_fn,

			IRQF_SHARED, devname, dev_id);

	if (ret)

		kfree(devname);

	return ret;

}

EXPORT_SYMBOL(pci_request_irq);



/**

 * pci_free_irq - free an interrupt allocated with pci_request_irq

 * @dev:	PCI device to operate on

 * @nr:		device-relative interrupt vector index (0-based).

 * @dev_id:	Device identity to free

 *

 * Remove an interrupt handler. The handler is removed and if the interrupt

 * line is no longer in use by any driver it is disabled.  The caller must

 * ensure the interrupt is disabled on the device before calling this function.

 * The function does not return until any executing interrupts for this IRQ

 * have completed.

 *

 * This function must not be called from interrupt context.

 */

void pci_free_irq(struct pci_dev *dev, unsigned int nr, void *dev_id)

{

	kfree(free_irq(pci_irq_vector(dev, nr), dev_id));

}

EXPORT_SYMBOL(pci_free_irq);

include/linux/pci.h

+6 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <linux/kobject.h>

#include <linux/atomic.h>

#include <linux/device.h>

#include <linux/interrupt.h>

#include <linux/io.h>

#include <linux/resource_ext.h>

#include <uapi/linux/pci.h>
@@ -1072,6 +1073,11 @@ int pci_select_bars(struct pci_dev *dev, unsigned long flags); 
bool pci_device_is_present(struct pci_dev *pdev);

void pci_ignore_hotplug(struct pci_dev *dev);



int __printf(6, 7) pci_request_irq(struct pci_dev *dev, unsigned int nr,

		irq_handler_t handler, irq_handler_t thread_fn, void *dev_id,

		const char *fmt, ...);

void pci_free_irq(struct pci_dev *dev, unsigned int nr, void *dev_id);



/* ROM control related routines */

int pci_enable_rom(struct pci_dev *pdev);

void pci_disable_rom(struct pci_dev *pdev);

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