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MPC8540 DMA routines (channel 0 broken?)

DISCUSSION Clemens Koller 1 participant 2 messages Jul 15, 2005 – Jul 18, 2005

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Hello,

I am about to bring Jason McMullan's DMA routines up to linux-2.6 Currently I am in the process of getting the things started step by step.

Until today I had a pretty hard time for some basic direct dma transfers because it seems that dma channel 0 doesn't work at all on my hardware (PPC8540PX833LB 2L71V MSIA QEAD0412).
The status register always stays 0x0 (means everything is happy and okay) but it doesn't copy any data. I cannot even trigger a programming error by a wrong configuration!
But when I let ch 1,2,3 do the work, everything
seems to work fine!
I havent found anything in the errata sheets or in the web. Can a DMA machine crash that it stays completely unusable? Have anybody seen similar things like that?

Some other questions:
I would also suggest to put my revised and almost complete immap_85xx.h and the mpc85xx_dma module into the current linux tree (Kumar?) to get things like that started more easily.
Why is Jason's work not in the Kernel?

If you are fine with that, I can offer some patches. But I first need to strip tons of the debug stuff from the last two weeks. :-/

Best greets,

Clemens Koller
_______________________________
R&D Imaging Devices
Anagramm GmbH
Rupert-Mayer-Str. 45/1
81379 Muenchen
Germany

http://www.anagramm.de
Phone: +49-89-741518-50
Fax: +49-89-741518-19

#1 lore raw

Hello again...

In the meanwhile, I got channel 0 working. It seems that the DMA#0 machine got stuck in some configuration from any previous (u-boot?) operation which didn't clean up things properly. I had to explicitly abort a (continously running?) transfer to be able to re-program it in the way I need.

Best greets,

Clemens Koller
_______________________________
R&D Imaging Devices
Anagramm GmbH
Rupert-Mayer-Str. 45/1
81379 Muenchen
Germany

http://www.anagramm.de
Phone: +49-89-741518-50
Fax: +49-89-741518-19

Quoted 47 lines · Clemens Koller

Hello,

I am about to bring Jason McMullan's DMA routines up to linux-2.6 Currently I am in the process of getting the things started step by step.

Until today I had a pretty hard time for some basic direct dma transfers because it seems that dma channel 0 doesn't work at all on my hardware (PPC8540PX833LB 2L71V MSIA QEAD0412).
The status register always stays 0x0 (means everything is happy and okay) but it doesn't copy any data. I cannot even trigger a programming error by a wrong configuration!
But when I let ch 1,2,3 do the work, everything
seems to work fine!
I havent found anything in the errata sheets or in the web. Can a DMA machine crash that it stays completely unusable? Have anybody seen similar things like that?

Some other questions:
I would also suggest to put my revised and almost complete immap_85xx.h and the mpc85xx_dma module into the current linux tree (Kumar?) to get things like that started more easily.
Why is Jason's work not in the Kernel?

If you are fine with that, I can offer some patches. But I first need to strip tons of the debug stuff from the last two weeks. :-/

Best greets,

Clemens Koller
_______________________________
R&D Imaging Devices
Anagramm GmbH
Rupert-Mayer-Str. 45/1
81379 Muenchen
Germany

http://www.anagramm.de
Phone: +49-89-741518-50
Fax: +49-89-741518-19
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