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 Post subject: how can I launch DMA in current X86_64 system
PostPosted: Tue Dec 12, 2017 2:38 am 
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Joined: Fri Nov 17, 2017 7:02 am
Posts: 8
Such as memory to memory copy by configuring/starting DMA engine in current X86_64 + PCH system?

Thanks,
-Tao


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 Post subject: Re: how can I launch DMA in current X86_64 system
PostPosted: Tue Dec 12, 2017 3:01 am 
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Joined: Sat Jan 15, 2005 12:00 am
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Hi,

wangt13 wrote:
Such as memory to memory copy by configuring/starting DMA engine in current X86_64 + PCH system?


Which DMA engine?

The old ISA DMA chips were originally able to be used for memory to memory copying, but that ended in the 1980s and more modern legacy DMA chips aren't able to do it.

For some Intel chipsets there's a "QuickData Technology Device" that might (should) also be able to do it; but it's far from standard (only provided on some server motherboards with Intel chipsets) and likely to be quite complex. I don't think anyone here has looked into writing a device driver for these (I know I haven't).

Mostly, it's probably better to just use something like "memcpy()".


Cheers,

Brendan

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