Adding Trent and Tim (as I think they managed to fix some imx6 MSI issues) On Fri, Nov 23, 2018 at 8:17 PM Robert Hancock <hancock@xxxxxxxxxxxxx> wrote: > > I am working with a custom FPGA PCI Express endpoint connected to an NXP > iMX6D processor running the 4.19.2 kernel. It seems happy using INTx > interrupts but when trying to enable MSI the device driver is not > receiving any interrupts. > > From some register poking I have figured out: > -the MSI address set on the PCIe device is correctly set in the iMX MSI > controller's MSI Controller Address register (0x1ffc820) > -the interrupt vectors are enabled in the MSI controller's Interrupt > Enable register (0x1ffc828) > -the interrupt vectors are not masked in the MSI controller's Interrupt > Mask register (0x1ffc82c) > -The MSI controller's Interrupt Status register (0x1ffc830) shows that > the requested interrupt vectors are pending > -In the ARM GIC, vector 152 (for msi_ctrl_int) is enabled in the IS > enable register (0x00a01110), but not set in the IS pending (0x00a01210) > or IS active (0x00a01310) registers > -Vector 152 is not masked in the GPC interrupt mask (0x00a01310) > -Vector 152 is not active in the GPC interrupt status (0x00a01310) > > So it appears the MSI controller is receiving and recognizing the MSI > from the device, but the interrupt is not making it into the GIC for > some reason. If I manually set vector 152 to pending in the GIC, the > dw_handle_msi_irq handler in pci-designware-host.c does get called along > with the interrupt handler(s) for the PCIe device, so it appears the > chain from that point on is working: > > # devmem 0x00a01210 32 0x1000000 > > I found someone else reporting this in 2014 with an unknown kernel > version on the NXP forums here, but with no resolution listed there: > > https://community.nxp.com/thread/318307 > > Any ideas on what may be going wrong? My next step may be to try an > older kernel version to see if this got broken at some point. > > -- > Robert Hancock > Senior Software Developer > SED Systems > Email: hancock@xxxxxxxxxxxxx > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
