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