Dear Penguins,
SHORT:
There is a BUG in the current code design / Freescale P2020/85xx PCIe design
that prevent it from registering to the PCIe AER... or that I have missed
something :) ..
LESS SHORT:
I am in the process of a Freescale P2020 based board bring up. P2020 is
basically two 85xx processors and their peripherals share most features.
PCIe has a very extensive error reporting section and the Kernel already has a
very nice looking Advanced Error Reporting driver.
I encounter difficulties trying to connect the P2020/85xx PCIe device to this
AER service driver.
My technical findings follows:
- pcie_portdrv_probe() will be called for every BRIDGE class PCI device. P2020 PCIe is a PCI-PCI BRIDGE class so no problem here.
- The code will continue to check that we have PCI_CAP_ID_EXP capability, which we have and continue to pcie_port_device_register().
- Now ,the function pcie_port_device_register() will FAIL. It will fail because
it will call assign_interrupt_mode(), return with PCIE_PORT_NO_IRQ, and giveup
with a reasonable remark in the code
"/*
* Don't use service devices that require interrupts if there is
* no way to generate them.
*/"
So now the question is why calling assign_interrupt_mode() with the P2020 PCIe
ROOT device return empty? Well...
- First assign_interrupt_mode() will test for PCIE_PORT_MSIX_MODE. Freescale
PCIe does not support this...
- Second attampt is made to discover PCIE_PORT_MSI_MODE, which Freescale should
support but the PCIe PCI_CAP_ID_MSI capability is published on the device side
of the bridge and NOT on the PCIe ROOT device, which is the one probed and thus
fails.
- Last it attempts to look at "dev->pin" in order to set PCIE_PORT_INTx_MODE.
On top of being the less recommended way (the old way), The Freescale PCIE ROOT device pin
is not set anywhere.
Failing all those the probe fails and the AER service is not activated for the
PCIE device.
QUESTION:
1. What am I missing?
2. Has anyone enabled the AER PCIe service for P2020/MPC85xx?
3. Should the PCIe ROOT end report MSI capabilities or should the device end
report itself as bridge ???
-- Liberty
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