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

Emilio G. Cota
2009-08-11T14:11:23Z

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.

Thanks,
E.