Subject: Re: Failing to get DMA working with MPC5200 (TQM5200) and CompactFlash

From: Josh Triplett <[email-masked]>
Date: Fri, 26 Mar 2010 14:32:02 -0700

On Fri, Mar 26, 2010 at 12:22:32PM -0600, Grant Likely wrote:
> On Tue, Mar 16, 2010 at 11:17 PM, Josh Triplett <[email-masked]> wrote:
> > Hello,
> >
> > We've tried both 2.6.33 and DENX-v2.6.33.1, and we haven't managed to
> > successfully use any form of DMA with the TQM5200 and a CompactFlash
> > card.  We know the CF card supports DMA (or, at least, it says "UDMA"
> > right on the card, and various reports say Lexar Professional CF cards
> > do DMA), but the kernel always puts the card in PIO4 mode.  We tried
> > libata.force=mwdma2 and libata.force=udma2 , and many other modes, but
> > this always led to failures like this:
> >
> > [   31.994311] ata1: lost interrupt (Status 0x58)
> > [   32.020435] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
> > [   32.027712] ata1.00: failed command: READ DMA
> > [   32.032236] ata1.00: cmd c8/00:08:00:00:00/00:00:00:00:00/e0 tag 0 dma 4096 in
> > [   32.032249]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
> > [   32.047212] ata1.00: status: { DRDY }
> > [   32.051050] ata1: soft resetting link
> > [   32.218796] ata1.00: FORCE: xfer_mask set to udma2
> > [   32.230618] ata1.00: configured for UDMA/33
> > [   32.235000] ata1.00: device reported invalid CHS sector 0
> > [   32.240629] ata1: EH complete
> > [   62.994310] ata1: lost interrupt (Status 0x58)
> > [   63.020443] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
> > [   63.027722] ata1.00: failed command: READ DMA
> > [   63.032246] ata1.00: cmd c8/00:08:00:00:00/00:00:00:00:00/e0 tag 0 dma 4096 in
> > [   63.032259]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
> > [   63.047221] ata1.00: status: { DRDY }
> > [   63.051060] ata1: soft resetting link
> > [   63.218778] ata1.00: FORCE: xfer_mask set to udma2
> > [   63.238603] ata1.00: configured for UDMA/33
> > [   63.242978] ata1.00: device reported invalid CHS sector 0
> > [   63.248609] ata1: EH complete
> >
> > We have the MPC5200C revision of the silicon.
> >
> > Does this sound like a known issue?  Can we do anything to troubleshoot
> > this further?
> 
> Not all CF adapters have all the pins wired up that are needed for
> *DMA modes.  That is the most likely problem.

True, but we bought a card that specifically advertises support for
UDMA, and says UDMA right on the card's label.

http://store.lexar.com/?productid=CF8GB-300-381

It seems unlikely, though not impossible, that they would have screwed
up that badly. :)

By the way, we've also tested an IDE hard drive on this board, and it
does UDMA2 just fine.

Any thoughts on how we could try to solve this problem?

- Josh Triplett