PCIe interrupts in the device tree

Johns Daniel johns.daniel at gmail.com
Wed Mar 25 07:24:50 EST 2009


Could somebody please explain the declaration of the PCIe interrupts
in the device tree?

I was under the impression that PCIe interrupts in the PowerPC Linux
kernel default to using INTx signaling (vs. external IRQ pin assertion
and MSI signaling). Am I right?

If so, then do the interrupt-map lines in the DTS refer to the
internal IRQ used by Freescale processors to implement INTx virtual
wire interrupts?

For example, in the mpc8536ds.dts file, under "pci1: pcie at ffe09000" we have:
		interrupt-map = <
			/* IDSEL 0x0 */
			0000 0 0 1 &mpic 4 1
			0000 0 0 2 &mpic 5 1
			0000 0 0 3 &mpic 6 1
			0000 0 0 4 &mpic 7 1
			>;
Are the 4, 5, 6, and 7 internal or external IRQs?

And the "msi at 41600" section in the same mpc8536ds.dts file does NOT
affect PCIe interrupts unless a driver calls pci_enable_msi()?

TIA!

-- Johns



More information about the Linuxppc-dev mailing list