Problem with mini-PCI-E slot on P2020RDB

[Kushwaha Prabhakar-B32579]

Added Linxppc-dev

> -----Original Message-----
> From: Aggrwal Poonam-B10812
> Sent: Friday, April 15, 2011 11:47 AM
> To: Felix Radensky
> Cc: Kushwaha Prabhakar-B32579; leon.woestenberg at gmail.com
> Subject: FW: Problem with mini-PCI-E slot on P2020RDB
> 
> Hello Felix
> 
> We checked with the Board designer, we need the board fixes "mentioned in
> Board errata doc" on the board for this issue. Sorry for the confusion.
> 
> The fixes are not present on RevC, also on some RevDs this fix also may
> be absent.
> 
> 
> Please let us know in case of any issues.
> 
> Regards
> Poonam
> 
> > -----Original Message-----
> > From: Leon Woestenberg [mailto:leon.woestenberg at gmail.com]
> > Sent: Wednesday, April 13, 2011 2:52 PM
> > To: Felix Radensky
> > Cc: Aggrwal Poonam-B10812; linuxppc-dev at ozlabs.org; Gupta
> > Maneesh-B18878; Kushwaha Prabhakar-B32579
> > Subject: Re: Problem with mini-PCI-E slot on P2020RDB
> >
> > Felix,
> >
> > On Tue, Apr 12, 2011 at 6:54 AM, Felix Radensky
> > <felix at embedded-sol.com>
> > wrote:
> > > On 04/12/2011 07:05 AM, Aggrwal Poonam-B10812 wrote:
> > >> As such there is no hardware fix related to this issue between RevC
> > >> to RevD. The solution was a software patch to resolve the issue
> > >> related to IRQ0.
> > >
> > > Are you sure ? Please take a look at Freescale document titled
> > > "P1020E/P2020E RDB System Errata".
> > > There's errata CE10, IRQ0 held low. It is fixed in Rev D. Vivek
> > > Mahajan, who looked at the issue back in 2009, estimated that
> > > problem can be related to missing pull-up on IRQ0.
> > > This is exactly what is
> > > fixed in Rev D.
> > >
> >
> > That's my understanding as well.
> >
> > Check if R420 and R423 are populated. These are the required pull-ups.
> > On Rev D they are populated. You might be able to add them yourself.
> >
> > Even if you have an Rev A-C PCB, this fix can already be applied; it
> > was on my board! (the bottom of the board mentions the schematic
> > revision)
> >
> > The resistors have a silkscreen designator block called X, the
> > resistors are situated to the left and bottom of the silkscreen X.
> > IIRC, between the flash and Px020 part.
> >
> > On the left side of R420 (or R423) I measured the block wave from the
> > RTC, which fires the 32kHz interrupt rate on IRQ0. This fixed by the
> > u- boot patch.
> >
> > Regards,
> >
> > Leon.