[U-Boot] bdi3000 configurtio file for mpc8308RDB

[David Hawkins <dwh@ovro.caltech.edu>]

Hi Wolfgang,

>> Grazing through the MPC8308 errata, there don't appear to be any
>> major 'gotchas' with this part. ...
>
> ... not unless you try to use USB device mode.

Ah, that is a gotcha then.

>> Has anyone had any bad experiences with this part, or is there
>> some 'feature' of the part I should be aware of?
>
> USB device mode doesn't work reliably, and FSL was never able or
> willing to come up with a solution.  When this issue happens, the USB
> device controller not only returns a truncated packet to the gadget
> driver, but doesn't report URB completion to the host either.  The
> host never gets an URB complete event, so you will see first a delay,
> and then the host resets the device.  The issue can be reproduced with
> massive writes to a mass-storage device.

The CPCI-S.0 specification defines USB, Ethernet, and PCIe over the
backplane.

We're going to use Ethernet for monitor/control traffic, and
PCIe for data transfers.

I had planned on using the PowerPC USB interface to implement at
least some form of 'USB device' communication with the board,
eg., something like USB-to-Serial or CDC class.

In your opinion, is MPC8308 USB Device Mode completely broken?

If that is the case, then if I want a UART over CPCI-S.0 USB,
I can use an FTDI FT245/FT232 on the CPCI-S.0 USB interface and
wire it into either a PowerPC UART or the system control FPGA.

How about USB Host mode? The board will communicate with a rear
transition module (another board plugged in from the rear side
of the chassis). If MPC8308 USB Host Mode is reliable, then I can
wire the USB interface through the backplane for use on the
RTM, eg., for talking to an FT245/232 device or a USB microcontroller.

Thanks for the valuable feedback.

Cheers,
Dave