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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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Christoph Hellwig 2017-04-13 09:06:42 +02:00 committed by Bjorn Helgaas
parent 25ce4be724
commit 704e8953d3
2 changed files with 66 additions and 1 deletions
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61
drivers/pci/irq.c
View File

@ -1,7 +1,8 @@
/*
* 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);

6
include/linux/pci.h
View File

@ -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);