Re: CPU Initiated DMA

From: Ming Lei
Date: Mon Jan 10 2011 - 09:21:53 EST


2011/1/8 Nikolaus Rath <Nikolaus@xxxxxxxx>:
Hi,

> Hello,
>
> I want to write a driver for a rather dumb PCI card, which cannot become
> bus master itself. Is it possible to use a DMA controller on the
> mainboard to still transfer data to the card without occupying the CPU?
>
> (I believe this is the way DMA used to work on ISA cards, but do recent
> x86 systems still have a DMA controller for the CPU?)
>
> Any pointers are greatly appreciated. I looked into "Linux Device
> Drivers", but the DMA chapter seems to be only about the device becoming
> busmaster.

Generally speaking, you can do it certainly if there is dma controller on
your system.

thanks,
--
Lei Ming
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