IDE DMA on 8xx ??

Steven Scholz steven.scholz at
Wed Mar 20 23:17:47 EST 2002

Hi Steve,

> Has anyone attempted to use the internal 8xx IDMA controller to do
> DMA to a IDE disk? I'm considering making an attempt at it, but I just
> want to hear first if anyone has tried already and if so what the
> experience is.

I did last summer. Well actually I tried. It wasn't too hard to use the
IDMA to transfer data from/to ide disk.

But at that time my code just started polling after setting up the dma.
So the cpu was busy waiting instead of doing something useful. But I
reckon it's not to hard to use irqs for signaling the end of DMA
transfer to the ide driver.

I noticed that the cycle time of the normal (i.e. two-address) IDMA mode
is huge. So the performance wasn't great.

I have to pick up that work again now.

So I wonder if you or anybody else has done something on this topic?



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