| Benjamin Herrenschmidt | 98d9f30 | 2011-04-11 11:37:07 +1000 | [diff] [blame] | 1 | #include <linux/kernel.h> |
| 2 | #include <linux/of_pci.h> |
| 3 | #include <linux/of_irq.h> |
| 4 | #include <asm/prom.h> |
| 5 | |
| 6 | /** |
| 7 | * of_irq_map_pci - Resolve the interrupt for a PCI device |
| 8 | * @pdev: the device whose interrupt is to be resolved |
| 9 | * @out_irq: structure of_irq filled by this function |
| 10 | * |
| 11 | * This function resolves the PCI interrupt for a given PCI device. If a |
| 12 | * device-node exists for a given pci_dev, it will use normal OF tree |
| 13 | * walking. If not, it will implement standard swizzling and walk up the |
| 14 | * PCI tree until an device-node is found, at which point it will finish |
| 15 | * resolving using the OF tree walking. |
| 16 | */ |
| 17 | int of_irq_map_pci(struct pci_dev *pdev, struct of_irq *out_irq) |
| 18 | { |
| 19 | struct device_node *dn, *ppnode; |
| 20 | struct pci_dev *ppdev; |
| 21 | u32 lspec; |
| 22 | __be32 lspec_be; |
| 23 | __be32 laddr[3]; |
| 24 | u8 pin; |
| 25 | int rc; |
| 26 | |
| 27 | /* Check if we have a device node, if yes, fallback to standard |
| 28 | * device tree parsing |
| 29 | */ |
| 30 | dn = pci_device_to_OF_node(pdev); |
| 31 | if (dn) { |
| 32 | rc = of_irq_map_one(dn, 0, out_irq); |
| 33 | if (!rc) |
| 34 | return rc; |
| 35 | } |
| 36 | |
| 37 | /* Ok, we don't, time to have fun. Let's start by building up an |
| 38 | * interrupt spec. we assume #interrupt-cells is 1, which is standard |
| 39 | * for PCI. If you do different, then don't use that routine. |
| 40 | */ |
| 41 | rc = pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin); |
| 42 | if (rc != 0) |
| 43 | return rc; |
| 44 | /* No pin, exit */ |
| 45 | if (pin == 0) |
| 46 | return -ENODEV; |
| 47 | |
| 48 | /* Now we walk up the PCI tree */ |
| 49 | lspec = pin; |
| 50 | for (;;) { |
| 51 | /* Get the pci_dev of our parent */ |
| 52 | ppdev = pdev->bus->self; |
| 53 | |
| 54 | /* Ouch, it's a host bridge... */ |
| 55 | if (ppdev == NULL) { |
| 56 | ppnode = pci_bus_to_OF_node(pdev->bus); |
| 57 | |
| 58 | /* No node for host bridge ? give up */ |
| 59 | if (ppnode == NULL) |
| 60 | return -EINVAL; |
| 61 | } else { |
| 62 | /* We found a P2P bridge, check if it has a node */ |
| 63 | ppnode = pci_device_to_OF_node(ppdev); |
| 64 | } |
| 65 | |
| 66 | /* Ok, we have found a parent with a device-node, hand over to |
| 67 | * the OF parsing code. |
| 68 | * We build a unit address from the linux device to be used for |
| 69 | * resolution. Note that we use the linux bus number which may |
| 70 | * not match your firmware bus numbering. |
| 71 | * Fortunately, in most cases, interrupt-map-mask doesn't |
| 72 | * include the bus number as part of the matching. |
| 73 | * You should still be careful about that though if you intend |
| 74 | * to rely on this function (you ship a firmware that doesn't |
| 75 | * create device nodes for all PCI devices). |
| 76 | */ |
| 77 | if (ppnode) |
| 78 | break; |
| 79 | |
| 80 | /* We can only get here if we hit a P2P bridge with no node, |
| 81 | * let's do standard swizzling and try again |
| 82 | */ |
| 83 | lspec = pci_swizzle_interrupt_pin(pdev, lspec); |
| 84 | pdev = ppdev; |
| 85 | } |
| 86 | |
| 87 | lspec_be = cpu_to_be32(lspec); |
| 88 | laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8)); |
| 89 | laddr[1] = laddr[2] = cpu_to_be32(0); |
| 90 | return of_irq_map_raw(ppnode, &lspec_be, 1, laddr, out_irq); |
| 91 | } |
| 92 | EXPORT_SYMBOL_GPL(of_irq_map_pci); |