// SPDX-License-Identifier: GPL-2.0
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/*
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* PCI IRQ handling code
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*
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* Copyright (c) 2008 James Bottomley <James.Bottomley@HansenPartnership.com>
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* Copyright (C) 2017 Christoph Hellwig.
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*/
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#include <linux/acpi.h>
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/pci.h>
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static void pci_note_irq_problem(struct pci_dev *pdev, const char *reason)
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{
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struct pci_dev *parent = to_pci_dev(pdev->dev.parent);
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pci_err(pdev, "Potentially misrouted IRQ (Bridge %s %04x:%04x)\n",
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dev_name(&parent->dev), parent->vendor, parent->device);
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pci_err(pdev, "%s\n", reason);
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pci_err(pdev, "Please report to linux-kernel@vger.kernel.org\n");
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WARN_ON(1);
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}
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/**
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* pci_lost_interrupt - reports a lost PCI interrupt
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* @pdev: device whose interrupt is lost
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*
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* The primary function of this routine is to report a lost interrupt
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* in a standard way which users can recognise (instead of blaming the
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* driver).
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*
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* Returns:
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* a suggestion for fixing it (although the driver is not required to
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* act on this).
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*/
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enum pci_lost_interrupt_reason pci_lost_interrupt(struct pci_dev *pdev)
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{
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if (pdev->msi_enabled || pdev->msix_enabled) {
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enum pci_lost_interrupt_reason ret;
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if (pdev->msix_enabled) {
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pci_note_irq_problem(pdev, "MSIX routing failure");
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ret = PCI_LOST_IRQ_DISABLE_MSIX;
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} else {
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pci_note_irq_problem(pdev, "MSI routing failure");
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ret = PCI_LOST_IRQ_DISABLE_MSI;
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}
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return ret;
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}
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#ifdef CONFIG_ACPI
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if (!(acpi_disabled || acpi_noirq)) {
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pci_note_irq_problem(pdev, "Potential ACPI misrouting please reboot with acpi=noirq");
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/* currently no way to fix acpi on the fly */
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return PCI_LOST_IRQ_DISABLE_ACPI;
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}
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#endif
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pci_note_irq_problem(pdev, "unknown cause (not MSI or ACPI)");
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return PCI_LOST_IRQ_NO_INFORMATION;
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}
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EXPORT_SYMBOL(pci_lost_interrupt);
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/**
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* pci_request_irq - allocate an interrupt line for a PCI device
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* @dev: PCI device to operate on
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* @nr: device-relative interrupt vector index (0-based).
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* @handler: Function to be called when the IRQ occurs.
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* Primary handler for threaded interrupts.
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* If NULL and thread_fn != NULL the default primary handler is
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* installed.
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* @thread_fn: Function called from the IRQ handler thread
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* If NULL, no IRQ thread is created
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* @dev_id: Cookie passed back to the handler function
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* @fmt: Printf-like format string naming the handler
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*
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* This call allocates interrupt resources and enables the interrupt line and
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* IRQ handling. From the point this call is made @handler and @thread_fn may
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* be invoked. All interrupts requested using this function might be shared.
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*
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* @dev_id must not be NULL and must be globally unique.
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*/
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int pci_request_irq(struct pci_dev *dev, unsigned int nr, irq_handler_t handler,
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irq_handler_t thread_fn, void *dev_id, const char *fmt, ...)
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{
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va_list ap;
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int ret;
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char *devname;
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unsigned long irqflags = IRQF_SHARED;
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if (!handler)
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irqflags |= IRQF_ONESHOT;
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va_start(ap, fmt);
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devname = kvasprintf(GFP_KERNEL, fmt, ap);
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va_end(ap);
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ret = request_threaded_irq(pci_irq_vector(dev, nr), handler, thread_fn,
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irqflags, devname, dev_id);
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if (ret)
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kfree(devname);
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return ret;
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}
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EXPORT_SYMBOL(pci_request_irq);
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/**
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* pci_free_irq - free an interrupt allocated with pci_request_irq
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* @dev: PCI device to operate on
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* @nr: device-relative interrupt vector index (0-based).
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* @dev_id: Device identity to free
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*
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* Remove an interrupt handler. The handler is removed and if the interrupt
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* line is no longer in use by any driver it is disabled. The caller must
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* ensure the interrupt is disabled on the device before calling this function.
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* The function does not return until any executing interrupts for this IRQ
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* have completed.
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*
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* This function must not be called from interrupt context.
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*/
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void pci_free_irq(struct pci_dev *dev, unsigned int nr, void *dev_id)
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{
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kfree(free_irq(pci_irq_vector(dev, nr), dev_id));
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}
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EXPORT_SYMBOL(pci_free_irq);
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