Line data    Source code

       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           0 : 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           0 :         unsigned long irqflags = IRQF_SHARED;
      40             : 
      41           0 :         if (!handler)
      42           0 :                 irqflags |= IRQF_ONESHOT;
      43             : 
      44           0 :         va_start(ap, fmt);
      45           0 :         devname = kvasprintf(GFP_KERNEL, fmt, ap);
      46           0 :         va_end(ap);
      47           0 :         if (!devname)
      48             :                 return -ENOMEM;
      49             : 
      50           0 :         ret = request_threaded_irq(pci_irq_vector(dev, nr), handler, thread_fn,
      51             :                                    irqflags, devname, dev_id);
      52           0 :         if (ret)
      53           0 :                 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           0 : void pci_free_irq(struct pci_dev *dev, unsigned int nr, void *dev_id)
      73             : {
      74           0 :         kfree(free_irq(pci_irq_vector(dev, nr), dev_id));
      75           0 : }
      76             : EXPORT_SYMBOL(pci_free_irq);