rionet driver with MMIO DMA capability

[Li Yang-R58472]

> -----Original Message-----
> From: Linuxppc-dev [mailto:linuxppc-dev-
> bounces+leoli=freescale.com at lists.ozlabs.org] On Behalf Of Vineeth
> Sent: Wednesday, July 04, 2012 1:16 AM
> To: linux-embedded at vger.kernel.org; linuxppc-dev at lists.ozlabs.org;
> linuxppc-embedded at ozlabs.org; Wood Scott-B07421;
> mporter at kernel.crashing.org
> Cc: ranenikhil19 at gmail.com
> Subject: rionet driver with MMIO DMA capability
> 
> 
> Hi,
> 
> With kernel mainstream version 3.5.rc-5 there's SRIO low level driver
> with DMA support for MMIO. But the rionet driver in the same kernel
> version doesnt support MMIO.
> 
> We are trying to find the maximum bandwidth that we can achieve using our
> custom board's(quad MPC8641 )  4-lane SRIO.
> Now we are worried how to use this SRIO low level driver effectively ?
> 
> The RIOnet driver (with 3.5.-rc5) uses message based communication. This
> doesnt use the DMA capability of low level driver. with this we are
> getting a bandwidth of nearly 900Mbps, which is very less.
> 
> Is there any example code or modified middle ware driver for rionet/ or
> any code which uses the low level driver apis with MMIO DMA??

We provided the support for DMA in the old BSPs but didn't got the luck to make it upstream.  I heard Alex (CCed) is working on an upstream-able version of the feature.  Probably he can help to provide some code.

Leo