RE: MPC8548 PCIe / PCI support with BSP MPC8548CDS 02/24/2006

We did the hardware fix described in the BSP user's manual to 
make PCIe work (according to the manual section 2.1, step 3).
I.e.
  1) removed R193 and R194 on the carrier card (rev 1.2)
  2) removed RN1 on the CPU daughter card
  2a) connected pad3 of RN1 to pin3 of U12 (IRQ0)
  2b) connected pad2 of RN1 to pin4 of U12 (IRQ1)

Does this fix the interrupt polarity problem (as well)?

Yes, I think so. You can plug a PCIe ethernet card to test it. 

We applied the provided kernel patch as well.
IMHO that patch just moves the local PCIe root-complex 
"out-of-space" so no detection of that one occurs any more.
This is what actually happens when "lspci" is run.

However we still don't see any devices behind the PCIe switch 
(e.g. a transparent PLX8516). It seems that the enumeration 
process (traversing through the bus hierarchy) in the kernel 
is somehow disabled.

:-), Maybe it's need more study. Could you enable the DEBUG and post the kernel verbose message?

Bottom line: Only one device accessible at all on the PCIe port.

Any further ideas?

Thanks,

   Florian

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Hi,

Zhang Wei-r63237 schrieb:

Yes, I think so. You can plug a PCIe ethernet card to test it. 

A single device always works.

:-), Maybe it's need more study. Could you enable the DEBUG and post the kernel verbose message?

We added lots of debug output and made some modifications (mostly delays 
between calls to early_read_config_dword() and 
early_write_config_dword() in pci_auto.c) and came to the conclusion 
that generic bridge devices (PCIe-to-PCI), even in a cascaded setup of 
three bridges, work fine.

However a PCIe switch (PLX8516/8532) doesn't work. The MPC8548 only 
detects a single device (i.e. primary side of the switch).
We are going to analyze the problem more deeply soon. It seems that the 
configuration space of that devices isn't properly set up.

The provided patch doesn't make any difference, besides that it is moved 
to a location where the PPC itself is not detected.

Please keep us informed if there is any progress besides Freescale, as I 
will do.

Cheers,

   Florian