#include <linux/kernel.h> #include <linux/of_pci.h> #include <linux/of_irq.h> #include <linux/export.h> #include <asm/prom.h> /** * of_irq_map_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_map_pci(const struct pci_dev *pdev, struct of_irq *out_irq) { struct device_node *dn, *ppnode; struct pci_dev *ppdev; u32 lspec; __be32 lspec_be; __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_map_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 */ lspec = pin; 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 */ lspec = pci_swizzle_interrupt_pin(pdev, lspec); pdev = ppdev; } lspec_be = cpu_to_be32(lspec); laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8)); laddr[1] = laddr[2] = cpu_to_be32(0); return of_irq_map_raw(ppnode, &lspec_be, 1, laddr, out_irq); } EXPORT_SYMBOL_GPL(of_irq_map_pci);