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98d9f30c BH |
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); |