diff options
Diffstat (limited to 'drivers/pci/irq.c')
| -rw-r--r-- | drivers/pci/irq.c | 305 |
1 files changed, 262 insertions, 43 deletions
diff --git a/drivers/pci/irq.c b/drivers/pci/irq.c index b008cf86b9c3..4555630be9ec 100644 --- a/drivers/pci/irq.c +++ b/drivers/pci/irq.c @@ -1,61 +1,280 @@ +// SPDX-License-Identifier: GPL-2.0 /* - * PCI IRQ failure handing code + * PCI IRQ handling code * * Copyright (c) 2008 James Bottomley <James.Bottomley@HansenPartnership.com> + * Copyright (C) 2017 Christoph Hellwig. */ -#include <linux/acpi.h> #include <linux/device.h> #include <linux/kernel.h> +#include <linux/errno.h> #include <linux/export.h> +#include <linux/interrupt.h> #include <linux/pci.h> -static void pci_note_irq_problem(struct pci_dev *pdev, const char *reason) +#include "pci.h" + +/** + * pci_request_irq - allocate an interrupt line for a PCI device + * @dev: PCI device to operate on + * @nr: device-relative interrupt vector index (0-based). + * @handler: Function to be called when the IRQ occurs. + * Primary handler for threaded interrupts. + * If NULL and thread_fn != NULL the default primary handler is + * installed. + * @thread_fn: Function called from the IRQ handler thread + * If NULL, no IRQ thread is created + * @dev_id: Cookie passed back to the handler function + * @fmt: Printf-like format string naming the handler + * + * This call allocates interrupt resources and enables the interrupt line and + * IRQ handling. From the point this call is made @handler and @thread_fn may + * be invoked. All interrupts requested using this function might be shared. + * + * @dev_id must not be NULL and must be globally unique. + */ +int pci_request_irq(struct pci_dev *dev, unsigned int nr, irq_handler_t handler, + irq_handler_t thread_fn, void *dev_id, const char *fmt, ...) +{ + va_list ap; + int ret; + char *devname; + unsigned long irqflags = IRQF_SHARED; + + if (!handler) + irqflags |= IRQF_ONESHOT; + + va_start(ap, fmt); + devname = kvasprintf(GFP_KERNEL, fmt, ap); + va_end(ap); + if (!devname) + return -ENOMEM; + + ret = request_threaded_irq(pci_irq_vector(dev, nr), handler, thread_fn, + irqflags, devname, dev_id); + if (ret) + kfree(devname); + return ret; +} +EXPORT_SYMBOL(pci_request_irq); + +/** + * pci_free_irq - free an interrupt allocated with pci_request_irq + * @dev: PCI device to operate on + * @nr: device-relative interrupt vector index (0-based). + * @dev_id: Device identity to free + * + * Remove an interrupt handler. The handler is removed and if the interrupt + * line is no longer in use by any driver it is disabled. The caller must + * ensure the interrupt is disabled on the device before calling this function. + * The function does not return until any executing interrupts for this IRQ + * have completed. + * + * This function must not be called from interrupt context. + */ +void pci_free_irq(struct pci_dev *dev, unsigned int nr, void *dev_id) +{ + kfree(free_irq(pci_irq_vector(dev, nr), dev_id)); +} +EXPORT_SYMBOL(pci_free_irq); + +/** + * pci_swizzle_interrupt_pin - swizzle INTx for device behind bridge + * @dev: the PCI device + * @pin: the INTx pin (1=INTA, 2=INTB, 3=INTC, 4=INTD) + * + * Perform INTx swizzling for a device behind one level of bridge. This is + * required by section 9.1 of the PCI-to-PCI bridge specification for devices + * behind bridges on add-in cards. For devices with ARI enabled, the slot + * number is always 0 (see the Implementation Note in section 2.2.8.1 of + * the PCI Express Base Specification, Revision 2.1) + */ +u8 pci_swizzle_interrupt_pin(const struct pci_dev *dev, u8 pin) +{ + int slot; + + if (pci_ari_enabled(dev->bus)) + slot = 0; + else + slot = PCI_SLOT(dev->devfn); + + return (((pin - 1) + slot) % 4) + 1; +} + +int pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge) { - struct pci_dev *parent = to_pci_dev(pdev->dev.parent); + u8 pin; + + pin = dev->pin; + if (!pin) + return -1; - dev_err(&pdev->dev, - "Potentially misrouted IRQ (Bridge %s %04x:%04x)\n", - dev_name(&parent->dev), parent->vendor, parent->device); - dev_err(&pdev->dev, "%s\n", reason); - dev_err(&pdev->dev, "Please report to linux-kernel@vger.kernel.org\n"); - WARN_ON(1); + while (!pci_is_root_bus(dev->bus)) { + pin = pci_swizzle_interrupt_pin(dev, pin); + dev = dev->bus->self; + } + *bridge = dev; + return pin; } /** - * pci_lost_interrupt - reports a lost PCI interrupt - * @pdev: device whose interrupt is lost - * - * The primary function of this routine is to report a lost interrupt - * in a standard way which users can recognise (instead of blaming the - * driver). - * - * Returns: - * a suggestion for fixing it (although the driver is not required to - * act on this). - */ -enum pci_lost_interrupt_reason pci_lost_interrupt(struct pci_dev *pdev) -{ - if (pdev->msi_enabled || pdev->msix_enabled) { - enum pci_lost_interrupt_reason ret; - - if (pdev->msix_enabled) { - pci_note_irq_problem(pdev, "MSIX routing failure"); - ret = PCI_LOST_IRQ_DISABLE_MSIX; - } else { - pci_note_irq_problem(pdev, "MSI routing failure"); - ret = PCI_LOST_IRQ_DISABLE_MSI; - } - return ret; + * pci_common_swizzle - swizzle INTx all the way to root bridge + * @dev: the PCI device + * @pinp: pointer to the INTx pin value (1=INTA, 2=INTB, 3=INTD, 4=INTD) + * + * Perform INTx swizzling for a device. This traverses through all PCI-to-PCI + * bridges all the way up to a PCI root bus. + */ +u8 pci_common_swizzle(struct pci_dev *dev, u8 *pinp) +{ + u8 pin = *pinp; + + while (!pci_is_root_bus(dev->bus)) { + pin = pci_swizzle_interrupt_pin(dev, pin); + dev = dev->bus->self; + } + *pinp = pin; + return PCI_SLOT(dev->devfn); +} +EXPORT_SYMBOL_GPL(pci_common_swizzle); + +void pci_assign_irq(struct pci_dev *dev) +{ + u8 pin; + u8 slot = -1; + int irq = 0; + struct pci_host_bridge *hbrg = pci_find_host_bridge(dev->bus); + + if (!(hbrg->map_irq)) { + pci_dbg(dev, "runtime IRQ mapping not provided by arch\n"); + return; + } + + /* + * If this device is not on the primary bus, we need to figure out + * which interrupt pin it will come in on. We know which slot it + * will come in on because that slot is where the bridge is. Each + * time the interrupt line passes through a PCI-PCI bridge we must + * apply the swizzle function. + */ + pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin); + /* Cope with illegal. */ + if (pin > 4) + pin = 1; + + if (pin) { + /* Follow the chain of bridges, swizzling as we go. */ + if (hbrg->swizzle_irq) + slot = (*(hbrg->swizzle_irq))(dev, &pin); + + /* + * If a swizzling function is not used, map_irq() must + * ignore slot. + */ + irq = (*(hbrg->map_irq))(dev, slot, pin); + if (irq == -1) + irq = 0; } -#ifdef CONFIG_ACPI - if (!(acpi_disabled || acpi_noirq)) { - pci_note_irq_problem(pdev, "Potential ACPI misrouting please reboot with acpi=noirq"); - /* currently no way to fix acpi on the fly */ - return PCI_LOST_IRQ_DISABLE_ACPI; + dev->irq = irq; + + pci_dbg(dev, "assign IRQ: got %d\n", dev->irq); + + /* + * Always tell the device, so the driver knows what is the real IRQ + * to use; the device does not use it. + */ + pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq); +} + +static bool pci_check_and_set_intx_mask(struct pci_dev *dev, bool mask) +{ + struct pci_bus *bus = dev->bus; + bool mask_updated = true; + u32 cmd_status_dword; + u16 origcmd, newcmd; + unsigned long flags; + bool irq_pending; + + /* + * We do a single dword read to retrieve both command and status. + * Document assumptions that make this possible. + */ + BUILD_BUG_ON(PCI_COMMAND % 4); + BUILD_BUG_ON(PCI_COMMAND + 2 != PCI_STATUS); + + raw_spin_lock_irqsave(&pci_lock, flags); + + bus->ops->read(bus, dev->devfn, PCI_COMMAND, 4, &cmd_status_dword); + + irq_pending = (cmd_status_dword >> 16) & PCI_STATUS_INTERRUPT; + + /* + * Check interrupt status register to see whether our device + * triggered the interrupt (when masking) or the next IRQ is + * already pending (when unmasking). + */ + if (mask != irq_pending) { + mask_updated = false; + goto done; } -#endif - pci_note_irq_problem(pdev, "unknown cause (not MSI or ACPI)"); - return PCI_LOST_IRQ_NO_INFORMATION; + + origcmd = cmd_status_dword; + newcmd = origcmd & ~PCI_COMMAND_INTX_DISABLE; + if (mask) + newcmd |= PCI_COMMAND_INTX_DISABLE; + if (newcmd != origcmd) + bus->ops->write(bus, dev->devfn, PCI_COMMAND, 2, newcmd); + +done: + raw_spin_unlock_irqrestore(&pci_lock, flags); + + return mask_updated; +} + +/** + * pci_check_and_mask_intx - mask INTx on pending interrupt + * @dev: the PCI device to operate on + * + * Check if the device dev has its INTx line asserted, mask it and return + * true in that case. False is returned if no interrupt was pending. + */ +bool pci_check_and_mask_intx(struct pci_dev *dev) +{ + return pci_check_and_set_intx_mask(dev, true); +} +EXPORT_SYMBOL_GPL(pci_check_and_mask_intx); + +/** + * pci_check_and_unmask_intx - unmask INTx if no interrupt is pending + * @dev: the PCI device to operate on + * + * Check if the device dev has its INTx line asserted, unmask it if not and + * return true. False is returned and the mask remains active if there was + * still an interrupt pending. + */ +bool pci_check_and_unmask_intx(struct pci_dev *dev) +{ + return pci_check_and_set_intx_mask(dev, false); +} +EXPORT_SYMBOL_GPL(pci_check_and_unmask_intx); + +/** + * pcibios_penalize_isa_irq - penalize an ISA IRQ + * @irq: ISA IRQ to penalize + * @active: IRQ active or not + * + * Permits the platform to provide architecture-specific functionality when + * penalizing ISA IRQs. This is the default implementation. Architecture + * implementations can override this. + */ +void __weak pcibios_penalize_isa_irq(int irq, int active) {} + +int __weak pcibios_alloc_irq(struct pci_dev *dev) +{ + return 0; +} + +void __weak pcibios_free_irq(struct pci_dev *dev) +{ } -EXPORT_SYMBOL(pci_lost_interrupt); |