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Re: Are PCI bridges automatically configured?

On Feb 25, 2005, at 3:44 PM, Kate Feng wrote:

Peter Dufault wrote:

On Feb 25, 2005, at 3:04 PM, Joel Sherrill <joel@OARcorp.com> wrote:

On a board with a nice Rom monitor like PPCBug, it is quite possible that it was initialized by the Bug.

If it was enabled by MOTLoad (the monitor on the MVME5500), then it has
a bug similar to RTEMS mvme5500 (arbitrarily limiting number of busses)
since the bus and device don't show up with pciShow (and other pciFoo)
commands in MOTLoad, but after increasing the number of busses in the
RTEMS source it is showing up in RTEMS using BSP_pciFindDevice.

Good to know I am not the only one who limited it.

I'm still not sure who enabled the bridge.

You did it. Any PMC device should have firmware to follow the PCI standard to respond to a PCI bridge search. You just enabled the search by increasing the limit of two.


Here's another note about the mvme5500 "BSP_pciFindDevice" in case you start looking at it. I'll look at it after I finish the drivers I'm writing if you don't get to it.

I've got two Acromag PMC730 PMC cards in the MVME5500 board's two PMC slots, and during startup both are found and configured by RTEMS. The debug output during RTEMS startup is (PCI_DEBUG is enabled):
PCI0 Bus0 Slot6 DeviceID 0x445715D5
PCI0_BASE_ADDRESS_0 0x80200000
PCI1 Bus0 Slot6 DeviceID 0x445715D5
PCI1_BASE_ADDRESS_1 0xE1100000

However, when I use BSP_pciFindDevice to try to access that second instance it doesn't find it, so there is some inconsistency between the startup code and BSP_pciFindDevice.

So the good news is the card I thought I'd have trouble accessing (the one on the other side of the previously unsupported PCI-PCI bridge for the PMCSPAN) is now accessible, but the bad news is that the card on the MVEM5500 that MOTLoad sees and that is found during startup isn't accessible. I didn't see a quick fix, so I'm back to developing the drivers then I'll look at this.


Peter Dufault
HD Associates, Inc.