drivers/pci/irq.c

   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/acpi.h>
  10 #include <linux/device.h>
  11 #include <linux/kernel.h>
  12 #include <linux/export.h>
  13 #include <linux/pci.h>
  14
  15 static void pci_note_irq_problem(struct pci_dev *pdev, const char *reason)
  16 {
  17         struct pci_dev *parent = to_pci_dev(pdev->dev.parent);
  18
  19         pci_err(pdev, "Potentially misrouted IRQ (Bridge %s %04x:%04x)\n",
  20                 dev_name(&parent->dev), parent->vendor, parent->device);
  21         pci_err(pdev, "%s\n", reason);
  22         pci_err(pdev, "Please report to linux-kernel@vger.kernel.org\n");
  23         WARN_ON(1);
  24 }
  25
  26 /**
  27  * pci_lost_interrupt - reports a lost PCI interrupt
  28  * @pdev:       device whose interrupt is lost
  29  *
  30  * The primary function of this routine is to report a lost interrupt
  31  * in a standard way which users can recognise (instead of blaming the
  32  * driver).
  33  *
  34  * Returns:
  35  * a suggestion for fixing it (although the driver is not required to
  36  * act on this).
  37  */
  38 enum pci_lost_interrupt_reason pci_lost_interrupt(struct pci_dev *pdev)
  39 {
  40         if (pdev->msi_enabled || pdev->msix_enabled) {
  41                 enum pci_lost_interrupt_reason ret;
  42
  43                 if (pdev->msix_enabled) {
  44                         pci_note_irq_problem(pdev, "MSIX routing failure");
  45                         ret = PCI_LOST_IRQ_DISABLE_MSIX;
  46                 } else {
  47                         pci_note_irq_problem(pdev, "MSI routing failure");
  48                         ret = PCI_LOST_IRQ_DISABLE_MSI;
  49                 }
  50                 return ret;
  51         }
  52 #ifdef CONFIG_ACPI
  53         if (!(acpi_disabled || acpi_noirq)) {
  54                 pci_note_irq_problem(pdev, "Potential ACPI misrouting please reboot with acpi=noirq");
  55                 /* currently no way to fix acpi on the fly */
  56                 return PCI_LOST_IRQ_DISABLE_ACPI;
  57         }
  58 #endif
  59         pci_note_irq_problem(pdev, "unknown cause (not MSI or ACPI)");
  60         return PCI_LOST_IRQ_NO_INFORMATION;
  61 }
  62 EXPORT_SYMBOL(pci_lost_interrupt);
  63
  64 /**
  65  * pci_request_irq - allocate an interrupt line for a PCI device
  66  * @dev:        PCI device to operate on
  67  * @nr:         device-relative interrupt vector index (0-based).
  68  * @handler:    Function to be called when the IRQ occurs.
  69  *              Primary handler for threaded interrupts.
  70  *              If NULL and thread_fn != NULL the default primary handler is
  71  *              installed.
  72  * @thread_fn:  Function called from the IRQ handler thread
  73  *              If NULL, no IRQ thread is created
  74  * @dev_id:     Cookie passed back to the handler function
  75  * @fmt:        Printf-like format string naming the handler
  76  *
  77  * This call allocates interrupt resources and enables the interrupt line and
  78  * IRQ handling. From the point this call is made @handler and @thread_fn may
  79  * be invoked.  All interrupts requested using this function might be shared.
  80  *
  81  * @dev_id must not be NULL and must be globally unique.
  82  */
  83 int pci_request_irq(struct pci_dev *dev, unsigned int nr, irq_handler_t handler,
  84                 irq_handler_t thread_fn, void *dev_id, const char *fmt, ...)
  85 {
  86         va_list ap;
  87         int ret;
  88         char *devname;
  89
  90         va_start(ap, fmt);
  91         devname = kvasprintf(GFP_KERNEL, fmt, ap);
  92         va_end(ap);
  93
  94         ret = request_threaded_irq(pci_irq_vector(dev, nr), handler, thread_fn,
  95                         IRQF_SHARED, devname, dev_id);
  96         if (ret)
  97                 kfree(devname);
  98         return ret;
  99 }
 100 EXPORT_SYMBOL(pci_request_irq);
 101
 102 /**
 103  * pci_free_irq - free an interrupt allocated with pci_request_irq
 104  * @dev:        PCI device to operate on
 105  * @nr:         device-relative interrupt vector index (0-based).
 106  * @dev_id:     Device identity to free
 107  *
 108  * Remove an interrupt handler. The handler is removed and if the interrupt
 109  * line is no longer in use by any driver it is disabled.  The caller must
 110  * ensure the interrupt is disabled on the device before calling this function.
 111  * The function does not return until any executing interrupts for this IRQ
 112  * have completed.
 113  *
 114  * This function must not be called from interrupt context.
 115  */
 116 void pci_free_irq(struct pci_dev *dev, unsigned int nr, void *dev_id)
 117 {
 118         kfree(free_irq(pci_irq_vector(dev, nr), dev_id));
 119 }
 120 EXPORT_SYMBOL(pci_free_irq);