diff options
Diffstat (limited to 'drivers/pci/irq.c')
| -rw-r--r-- | drivers/pci/irq.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/drivers/pci/irq.c b/drivers/pci/irq.c index 0050e8f6814e..4555630be9ec 100644 --- a/drivers/pci/irq.c +++ b/drivers/pci/irq.c @@ -8,9 +8,13 @@ #include <linux/device.h> #include <linux/kernel.h> +#include <linux/errno.h> #include <linux/export.h> +#include <linux/interrupt.h> #include <linux/pci.h> +#include "pci.h" + /** * pci_request_irq - allocate an interrupt line for a PCI device * @dev: PCI device to operate on @@ -74,3 +78,203 @@ 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) +{ + u8 pin; + + pin = dev->pin; + if (!pin) + return -1; + + while (!pci_is_root_bus(dev->bus)) { + pin = pci_swizzle_interrupt_pin(dev, pin); + dev = dev->bus->self; + } + *bridge = dev; + return pin; +} + +/** + * 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; + } + 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; + } + + 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) +{ +} |