diff options
Diffstat (limited to 'drivers/of/of_pci_irq.c')
| -rw-r--r-- | drivers/of/of_pci_irq.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/drivers/of/of_pci_irq.c b/drivers/of/of_pci_irq.c new file mode 100644 index 00000000000..1710d9dc7fc --- /dev/null +++ b/drivers/of/of_pci_irq.c @@ -0,0 +1,116 @@ +#include <linux/kernel.h> +#include <linux/of_pci.h> +#include <linux/of_irq.h> +#include <linux/export.h> + +/** + * of_irq_parse_pci - Resolve the interrupt for a PCI device + * @pdev: the device whose interrupt is to be resolved + * @out_irq: structure of_irq filled by this function + * + * This function resolves the PCI interrupt for a given PCI device. If a + * device-node exists for a given pci_dev, it will use normal OF tree + * walking. If not, it will implement standard swizzling and walk up the + * PCI tree until an device-node is found, at which point it will finish + * resolving using the OF tree walking. + */ +int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq) +{ + struct device_node *dn, *ppnode; + struct pci_dev *ppdev; + __be32 laddr[3]; + u8 pin; + int rc; + + /* Check if we have a device node, if yes, fallback to standard + * device tree parsing + */ + dn = pci_device_to_OF_node(pdev); + if (dn) { + rc = of_irq_parse_one(dn, 0, out_irq); + if (!rc) + return rc; + } + + /* Ok, we don't, time to have fun. Let's start by building up an + * interrupt spec. we assume #interrupt-cells is 1, which is standard + * for PCI. If you do different, then don't use that routine. + */ + rc = pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin); + if (rc != 0) + return rc; + /* No pin, exit */ + if (pin == 0) + return -ENODEV; + + /* Now we walk up the PCI tree */ + for (;;) { + /* Get the pci_dev of our parent */ + ppdev = pdev->bus->self; + + /* Ouch, it's a host bridge... */ + if (ppdev == NULL) { + ppnode = pci_bus_to_OF_node(pdev->bus); + + /* No node for host bridge ? give up */ + if (ppnode == NULL) + return -EINVAL; + } else { + /* We found a P2P bridge, check if it has a node */ + ppnode = pci_device_to_OF_node(ppdev); + } + + /* Ok, we have found a parent with a device-node, hand over to + * the OF parsing code. + * We build a unit address from the linux device to be used for + * resolution. Note that we use the linux bus number which may + * not match your firmware bus numbering. + * Fortunately, in most cases, interrupt-map-mask doesn't + * include the bus number as part of the matching. + * You should still be careful about that though if you intend + * to rely on this function (you ship a firmware that doesn't + * create device nodes for all PCI devices). + */ + if (ppnode) + break; + + /* We can only get here if we hit a P2P bridge with no node, + * let's do standard swizzling and try again + */ + pin = pci_swizzle_interrupt_pin(pdev, pin); + pdev = ppdev; + } + + out_irq->np = ppnode; + out_irq->args_count = 1; + out_irq->args[0] = pin; + laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8)); + laddr[1] = laddr[2] = cpu_to_be32(0); + return of_irq_parse_raw(laddr, out_irq); +} +EXPORT_SYMBOL_GPL(of_irq_parse_pci); + +/** + * of_irq_parse_and_map_pci() - Decode a PCI irq from the device tree and map to a virq + * @dev: The pci device needing an irq + * @slot: PCI slot number; passed when used as map_irq callback. Unused + * @pin: PCI irq pin number; passed when used as map_irq callback. Unused + * + * @slot and @pin are unused, but included in the function so that this + * function can be used directly as the map_irq callback to pci_fixup_irqs(). + */ +int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin) +{ + struct of_phandle_args oirq; + int ret; + + ret = of_irq_parse_pci(dev, &oirq); + if (ret) { + dev_err(&dev->dev, "of_irq_parse_pci() failed with rc=%d\n", ret); + return 0; /* Proper return code 0 == NO_IRQ */ + } + + return irq_create_of_mapping(&oirq); +} +EXPORT_SYMBOL_GPL(of_irq_parse_and_map_pci); + |