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Benjamin Herrenschmidt98d9f30c82011-04-11 11:37:07 +10001#include <linux/kernel.h>
2#include <linux/of_pci.h>
3#include <linux/of_irq.h>
Paul Gortmaker2c8d6672011-07-29 16:05:38 +10004#include <linux/export.h>
Benjamin Herrenschmidt98d9f30c82011-04-11 11:37:07 +10005
6/**
Grant Likely0c02c802013-09-19 11:22:36 -05007 * of_irq_parse_pci - Resolve the interrupt for a PCI device
Benjamin Herrenschmidt98d9f30c82011-04-11 11:37:07 +10008 * @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 */
Grant Likely530210c2013-09-15 16:39:11 +010017int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
Benjamin Herrenschmidt98d9f30c82011-04-11 11:37:07 +100018{
19 struct device_node *dn, *ppnode;
20 struct pci_dev *ppdev;
Benjamin Herrenschmidt98d9f30c82011-04-11 11:37:07 +100021 __be32 laddr[3];
22 u8 pin;
23 int rc;
24
25 /* Check if we have a device node, if yes, fallback to standard
26 * device tree parsing
27 */
28 dn = pci_device_to_OF_node(pdev);
29 if (dn) {
Grant Likely0c02c802013-09-19 11:22:36 -050030 rc = of_irq_parse_one(dn, 0, out_irq);
Benjamin Herrenschmidt98d9f30c82011-04-11 11:37:07 +100031 if (!rc)
32 return rc;
33 }
34
35 /* Ok, we don't, time to have fun. Let's start by building up an
36 * interrupt spec. we assume #interrupt-cells is 1, which is standard
37 * for PCI. If you do different, then don't use that routine.
38 */
39 rc = pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin);
40 if (rc != 0)
41 return rc;
42 /* No pin, exit */
43 if (pin == 0)
44 return -ENODEV;
45
46 /* Now we walk up the PCI tree */
Benjamin Herrenschmidt98d9f30c82011-04-11 11:37:07 +100047 for (;;) {
48 /* Get the pci_dev of our parent */
49 ppdev = pdev->bus->self;
50
51 /* Ouch, it's a host bridge... */
52 if (ppdev == NULL) {
53 ppnode = pci_bus_to_OF_node(pdev->bus);
54
55 /* No node for host bridge ? give up */
56 if (ppnode == NULL)
57 return -EINVAL;
58 } else {
59 /* We found a P2P bridge, check if it has a node */
60 ppnode = pci_device_to_OF_node(ppdev);
61 }
62
63 /* Ok, we have found a parent with a device-node, hand over to
64 * the OF parsing code.
65 * We build a unit address from the linux device to be used for
66 * resolution. Note that we use the linux bus number which may
67 * not match your firmware bus numbering.
68 * Fortunately, in most cases, interrupt-map-mask doesn't
69 * include the bus number as part of the matching.
70 * You should still be careful about that though if you intend
71 * to rely on this function (you ship a firmware that doesn't
72 * create device nodes for all PCI devices).
73 */
74 if (ppnode)
75 break;
76
77 /* We can only get here if we hit a P2P bridge with no node,
78 * let's do standard swizzling and try again
79 */
Sergei Shtylyov08cf78e2014-05-25 22:50:06 +040080 pin = pci_swizzle_interrupt_pin(pdev, pin);
Benjamin Herrenschmidt98d9f30c82011-04-11 11:37:07 +100081 pdev = ppdev;
82 }
83
Grant Likely23616132013-09-15 22:32:39 +010084 out_irq->np = ppnode;
85 out_irq->args_count = 1;
Sergei Shtylyov08cf78e2014-05-25 22:50:06 +040086 out_irq->args[0] = pin;
Benjamin Herrenschmidt98d9f30c82011-04-11 11:37:07 +100087 laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
Grant Likely23616132013-09-15 22:32:39 +010088 laddr[1] = laddr[2] = cpu_to_be32(0);
89 return of_irq_parse_raw(laddr, out_irq);
Benjamin Herrenschmidt98d9f30c82011-04-11 11:37:07 +100090}
Grant Likely0c02c802013-09-19 11:22:36 -050091EXPORT_SYMBOL_GPL(of_irq_parse_pci);
Grant Likely16b84e52013-09-19 16:44:55 -050092
93/**
94 * of_irq_parse_and_map_pci() - Decode a PCI irq from the device tree and map to a virq
95 * @dev: The pci device needing an irq
96 * @slot: PCI slot number; passed when used as map_irq callback. Unused
97 * @pin: PCI irq pin number; passed when used as map_irq callback. Unused
98 *
99 * @slot and @pin are unused, but included in the function so that this
100 * function can be used directly as the map_irq callback to pci_fixup_irqs().
101 */
102int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin)
103{
104 struct of_phandle_args oirq;
105 int ret;
106
107 ret = of_irq_parse_pci(dev, &oirq);
108 if (ret) {
109 dev_err(&dev->dev, "of_irq_parse_pci() failed with rc=%d\n", ret);
110 return 0; /* Proper return code 0 == NO_IRQ */
111 }
112
113 return irq_create_of_mapping(&oirq);
114}
115EXPORT_SYMBOL_GPL(of_irq_parse_and_map_pci);
116