tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#include <linux/kernel.h>
2#include <linux/of_pci.h>
3#include <linux/of_irq.h>
4#include <linux/export.h>
5
6/**
7 * of_irq_parse_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 */
17int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *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_parse_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 out_irq->np = ppnode;
88 out_irq->args_count = 1;
89 out_irq->args[0] = lspec;
90 lspec_be = cpu_to_be32(lspec);
91 laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
92 laddr[1] = laddr[2] = cpu_to_be32(0);
93 return of_irq_parse_raw(laddr, out_irq);
94}
95EXPORT_SYMBOL_GPL(of_irq_parse_pci);
96
97/**
98 * of_irq_parse_and_map_pci() - Decode a PCI irq from the device tree and map to a virq
99 * @dev: The pci device needing an irq
100 * @slot: PCI slot number; passed when used as map_irq callback. Unused
101 * @pin: PCI irq pin number; passed when used as map_irq callback. Unused
102 *
103 * @slot and @pin are unused, but included in the function so that this
104 * function can be used directly as the map_irq callback to pci_fixup_irqs().
105 */
106int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin)
107{
108 struct of_phandle_args oirq;
109 int ret;
110
111 ret = of_irq_parse_pci(dev, &oirq);
112 if (ret) {
113 dev_err(&dev->dev, "of_irq_parse_pci() failed with rc=%d\n", ret);
114 return 0; /* Proper return code 0 == NO_IRQ */
115 }
116
117 return irq_create_of_mapping(&oirq);
118}
119EXPORT_SYMBOL_GPL(of_irq_parse_and_map_pci);
120