LXR linux/drivers/of/of_pci

   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        __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) {
  30                rc = of_irq_parse_one(dn, 0, out_irq);
  31                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                goto err;
  42        /* No pin, exit with no error message. */
  43        if (pin == 0)
  44                return -ENODEV;
  45
  46        /* Now we walk up the PCI tree */
  47        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                                rc = -EINVAL;
  58                                goto err;
  59                        }
  60                } else {
  61                        /* We found a P2P bridge, check if it has a node */
  62                        ppnode = pci_device_to_OF_node(ppdev);
  63                }
  64
  65                /* Ok, we have found a parent with a device-node, hand over to
  66                 * the OF parsing code.
  67                 * We build a unit address from the linux device to be used for
  68                 * resolution. Note that we use the linux bus number which may
  69                 * not match your firmware bus numbering.
  70                 * Fortunately, in most cases, interrupt-map-mask doesn't
  71                 * include the bus number as part of the matching.
  72                 * You should still be careful about that though if you intend
  73                 * to rely on this function (you ship  a firmware that doesn't
  74                 * create device nodes for all PCI devices).
  75                 */
  76                if (ppnode)
  77                        break;
  78
  79                /* We can only get here if we hit a P2P bridge with no node,
  80                 * let's do standard swizzling and try again
  81                 */
  82                pin = pci_swizzle_interrupt_pin(pdev, pin);
  83                pdev = ppdev;
  84        }
  85
  86        out_irq->np = ppnode;
  87        out_irq->args_count = 1;
  88        out_irq->args[0] = pin;
  89        laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
  90        laddr[1] = laddr[2] = cpu_to_be32(0);
  91        rc = of_irq_parse_raw(laddr, out_irq);
  92        if (rc)
  93                goto err;
  94        return 0;
  95err:
  96        dev_err(&pdev->dev, "of_irq_parse_pci() failed with rc=%d\n", rc);
  97        return rc;
  98}
  99EXPORT_SYMBOL_GPL(of_irq_parse_pci);
 100
 101/**
 102 * of_irq_parse_and_map_pci() - Decode a PCI irq from the device tree and map to a virq
 103 * @dev: The pci device needing an irq
 104 * @slot: PCI slot number; passed when used as map_irq callback. Unused
 105 * @pin: PCI irq pin number; passed when used as map_irq callback. Unused
 106 *
 107 * @slot and @pin are unused, but included in the function so that this
 108 * function can be used directly as the map_irq callback to pci_fixup_irqs().
 109 */
 110int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin)
 111{
 112        struct of_phandle_args oirq;
 113        int ret;
 114
 115        ret = of_irq_parse_pci(dev, &oirq);
 116        if (ret)
 117                return 0; /* Proper return code 0 == NO_IRQ */
 118
 119        return irq_create_of_mapping(&oirq);
 120}
 121EXPORT_SYMBOL_GPL(of_irq_parse_and_map_pci);
 122
 123