[patch 1/5] Staging: VME Framework for the Linux Kernel

Emilio G. Cota cota at braap.org
Tue Aug 11 08:43:02 UTC 2009

Martyn Welch wrote:
> Emilio G. Cota wrote:
>> Again, he (the driver writer) should know *nothing* about that.
>> As for the scatter-gather case, what should happen is:
>> User:		hey, there's a buffer I want to transfer. here's
>> 		a pointer and size
> Buffer where? On VME or PCI, where are you transferring it to? The API I  
> have will allow scattered locations on VME to be copied to PCI and  
> visa-versa, scattered locations on PCI to be copied to VME and  
> visa-versa. Even scattered locations on VME to scattered locations on  
> PCI with a bit of effort.

Admittedly our current tsi148 driver deals with the most common
situation: DMA from main (master) CPU RAM to/from a VME slave.

I'm not claiming we shouldn't support sg lists; however the
implementation should resemble the existing sg interfaces.
I'm currently working on something along those lines.


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