blob: c175d9cd0bb53efc39b2adad42820bbab7fc90d5 [file] [log] [blame]
#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)
goto err;
/* No pin, exit with no error message. */
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) {
rc = -EINVAL;
goto err;
} 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)
/* 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);
rc = of_irq_parse_raw(laddr, out_irq);
if (rc)
goto err;
return 0;
if (rc == -ENOENT) {
"%s: no interrupt-map found, INTx interrupts not available\n",
pr_warn_once("%s: possibly some PCI slots don't have level triggered interrupts capability\n",
} else {
dev_err(&pdev->dev, "%s: failed with rc=%d\n", __func__, rc);
return rc;
* 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)
return 0; /* Proper return code 0 == NO_IRQ */
return irq_create_of_mapping(&oirq);