Re: [ts-7000] Re: TS-7390 tssdcard and tsuart driver incompatibility with DMA

["Donal O'Connor" <>]

I and others also had weird behaviour of the SD card when using the serial port.
SD card driver process would go 100% and the world stops with the TS7390 and miss bytes on the SD card read buffer. Never get in.

On Mon, Aug 10, 2009 at 10:58 AM, Daniel Smolik <> wrote:

 

Doug napsal(a):
>
>
> --- In ts-7000%40yahoogroups.com <mailto:ts-7000%2540yahoogroups.com>,

> "Breton M. Saunders" <> wrote:
>
> Hey Brett,
>
> > I am unconvinced by the stability of the sdcard driver.
>
> Me too. We first noticed this problem because it was causing corrupted
> versions of shared libraries to be loaded into RAM, causing a strange
> program crash. We also saw other odd behavior (playsound was cutting out
> on some sounds and making the sounds stutter, and saying invalid format
> on others). When we loaded our program from the NAND instead of the SD
> card all was fine. Hopefully it's an easy fix, we'll see...anyway, we've
> seen a lot of random weird behavior with the SD card and we're hoping
> this problem I reported is the root cause of it. We tried to reduce it
> down to a simple test case so it would be easy to reproduce.
>
> > I'm not sure about the 7350 - but on the TS7400 there is a design issue
> > (or rather lack of clarity): The port_b4 gpio line doubles up as the
> > dmaenable line for dma channel 0. This is undocumented - and caused a
> > problem with a board I designed. The issue arises when using dma
> > enabled on the driver and channel 0 is used.
> >
> > The driver software for the 8 bit CPLD interfaces (7250 and 7400)
> > contain a busy wait loop in them to stop faulty signaling on them. Im
> > not sure about the 16 bit interfaces (e.g. the 73 series) - but there
> > may be an equivalent loop or a race condition in that loop in the driver.
> >
> > Id suggest checking that the two external DMA signaling lines aren't
> > attached to any circuitry you may be using.
>
> Thanks for the ideas...we'll definitely check on this on Monday to make
> sure. We've seen this problem on two TS-7390 boards, and on one of them
> I believe all we had hooked up externally was the two wires to the TS
> uart and an ethernet cable, so I dunno.
>
> > Does anyone fancy co-operating on reverse engineering and open sourcing
> > the SDcard driver?
> > Is doing that legal?
>
> Not sure on the legality of it. I think it would be easier to just take
> the binary blob as is and port the open source portion of the driver to
> newer kernel versions perhaps? It would be an interesting thing to try
> (either method).
>

But it is lot of work I spend lot of time to try port wrapper from 2.6.21 to 28 but it is not possible.
There are lot of internal changes in kernel BIO layer. I mean that wrapper driver must be rewritten from scratch.

Regards
Dan

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