--- /dev/null
+#include <linux/kernel.h>
+#include <linux/of_pci.h>
+#include <linux/of_irq.h>
+#include <linux/export.h>
+
+/**
+ * of_irq_parse_pci - Resolve the interrupt for a PCI device
+ * @pdev: the device whose interrupt is to be resolved
+ * @out_irq: structure of_irq filled by this function
+ *
+ * This function resolves the PCI interrupt for a given PCI device. If a
+ * device-node exists for a given pci_dev, it will use normal OF tree
+ * walking. If not, it will implement standard swizzling and walk up the
+ * PCI tree until an device-node is found, at which point it will finish
+ * resolving using the OF tree walking.
+ */
+int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
+{
+ struct device_node *dn, *ppnode;
+ struct pci_dev *ppdev;
+ __be32 laddr[3];
+ u8 pin;
+ int rc;
+
+ /* Check if we have a device node, if yes, fallback to standard
+ * device tree parsing
+ */
+ dn = pci_device_to_OF_node(pdev);
+ if (dn) {
+ rc = of_irq_parse_one(dn, 0, out_irq);
+ if (!rc)
+ return rc;
+ }
+
+ /* Ok, we don't, time to have fun. Let's start by building up an
+ * interrupt spec. we assume #interrupt-cells is 1, which is standard
+ * for PCI. If you do different, then don't use that routine.
+ */
+ rc = pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin);
+ if (rc != 0)
+ return rc;
+ /* No pin, exit */
+ if (pin == 0)
+ return -ENODEV;
+
+ /* Now we walk up the PCI tree */
+ for (;;) {
+ /* Get the pci_dev of our parent */
+ ppdev = pdev->bus->self;
+
+ /* Ouch, it's a host bridge... */
+ if (ppdev == NULL) {
+ ppnode = pci_bus_to_OF_node(pdev->bus);
+
+ /* No node for host bridge ? give up */
+ if (ppnode == NULL)
+ return -EINVAL;
+ } else {
+ /* We found a P2P bridge, check if it has a node */
+ ppnode = pci_device_to_OF_node(ppdev);
+ }
+
+ /* Ok, we have found a parent with a device-node, hand over to
+ * the OF parsing code.
+ * We build a unit address from the linux device to be used for
+ * resolution. Note that we use the linux bus number which may
+ * not match your firmware bus numbering.
+ * Fortunately, in most cases, interrupt-map-mask doesn't
+ * include the bus number as part of the matching.
+ * You should still be careful about that though if you intend
+ * to rely on this function (you ship a firmware that doesn't
+ * create device nodes for all PCI devices).
+ */
+ if (ppnode)
+ break;
+
+ /* We can only get here if we hit a P2P bridge with no node,
+ * let's do standard swizzling and try again
+ */
+ pin = pci_swizzle_interrupt_pin(pdev, pin);
+ pdev = ppdev;
+ }
+
+ out_irq->np = ppnode;
+ out_irq->args_count = 1;
+ out_irq->args[0] = pin;
+ laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
+ laddr[1] = laddr[2] = cpu_to_be32(0);
+ return of_irq_parse_raw(laddr, out_irq);
+}
+EXPORT_SYMBOL_GPL(of_irq_parse_pci);
+
+/**
+ * of_irq_parse_and_map_pci() - Decode a PCI irq from the device tree and map to a virq
+ * @dev: The pci device needing an irq
+ * @slot: PCI slot number; passed when used as map_irq callback. Unused
+ * @pin: PCI irq pin number; passed when used as map_irq callback. Unused
+ *
+ * @slot and @pin are unused, but included in the function so that this
+ * function can be used directly as the map_irq callback to pci_fixup_irqs().
+ */
+int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin)
+{
+ struct of_phandle_args oirq;
+ int ret;
+
+ ret = of_irq_parse_pci(dev, &oirq);
+ if (ret) {
+ dev_err(&dev->dev, "of_irq_parse_pci() failed with rc=%d\n", ret);
+ return 0; /* Proper return code 0 == NO_IRQ */
+ }
+
+ return irq_create_of_mapping(&oirq);
+}
+EXPORT_SYMBOL_GPL(of_irq_parse_and_map_pci);
+
Code Review / kvmfornfv.git / blobdiff