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); 122