usb hub problem on 8270

Nigel Rudgley nrudgley at
Tue Mar 23 20:59:48 EST 2004

Hi Jaap-Jan

We're trying to bring up UBS host on the PQFADS board (8280 based) and have
recently got it running on an Adder-II board (870 based)

Maybe our experience with 870 can help - your problem looks a lot like what
we saw with the Adder board, some transmits, detecting a hub, then...

The CPM has been altered slightly from the 823/850 and will now effect a
graceful stop when it receives a nak or stall response, you now have to
restart it manually after these are detected.

In original m8xxhci.c, this needs to be done in process_done_txbds()
around line 2183, inside "if (nak & BD_USB_NAK)"
around line 2197, inside "if ((nak & BD_USB_STAL))"
around line 2213, inside "if (nak)"

calling restart_endpoint() at these three points should work to wake up the
cpm :-)

I can send a complete patch file but other changes won't be so relevant for
you, they're for 870.

On the other hand you look further on with the 8270 than we are with the
8280, we're not seeing SOFs :-( Do we need a microcode patch on the 82xx? Do
the IDMAs need setting up to get DREQs in the right configuration or does it
just work with the external wire connected?


nrudgley at

----- Original Message -----
From: "Jaap-Jan Boor" <jjboor at>
To: <linuxppc-embedded at>
Sent: Thursday, February 19, 2004 9:28 PM
Subject: usb hub problem on 8270

> Hi,
> I found some time to adapt m8xxhci.c (for 823/850) to the 8270 with
> limited success.
> We use TOUT3 (from timer3) to DREQ0/1 to enable SOF transmitting which
> works
> more or less as one of my hubs is detected but after the host driver
> received the hub's
> device description, I get a time-out and, well that's it. Even after
> resetting the 8270 and cpm
> I'm unable to communicate to the hub:

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