Subject: Re: BUS_DMA_CONTROLDATA flag for bus_dma(9)
To: None <tech-kern@netbsd.org>
From: Matt Thomas <matt@3am-software.com>
List: tech-kern
Date: 08/14/2003 18:46:07
On Thursday, August 14, 2003, at 06:24 PM, Allen Briggs wrote:
>> Re: Making COHERENT required: yes. I think this has to be done; I
>> think the existing specification is defective.
>
> I'm thinking that I agree with you, but I'm not quite clear on how
> BUS_DMA_COHERENT should be defined in this case.
To me, BUS_DMA_COHERENT is used on maps that are concurrently read and
written without re-mapping. Of course, having BUS_DMA_READ,
BUS_DMA_WRITE, and BUS_DMA_READWRITE might be more useful
--
Matt Thomas email: matt@3am-software.com
3am Software Foundry www:
http://3am-software.com/bio/matt/ Cupertino, CA
disclaimer: I avow all knowledge of this message.