Re: [PATCH v3 5/7] mtd: onenand: omap2: Unify OMAP2 and OMAP3 DMA implementation

[Tony Lindgren <tony@atomide.com>]

* Ladislav Michl <ladis@linux-mips.org> [171110 21:41]:
> On Fri, Nov 10, 2017 at 07:24:23AM -0800, Tony Lindgren wrote:
> > FYI, the gpio pin for onenand should not be in gpio mode. It should
> > be used as external dma request line to automatically trigger new
> > transfers like we do for tusb6010 dma. But of course it's possible
> > that onenand has other issues too preventing the dma usage.
> 
> Now, after reading dma and interrupt related code again, I still do
> not see how the driver could be using hardware synchronized transfer.
> DMA seems to be used as a memcpy and gpio pin a ready/busy.
> Care to elaborate a bit more?

Well take a look at mux options for the onenand connected pins,
and if there is one that has a mux option for ext_dmareq or similar,
chances are it can be used to retrigger dma transfers.

I could be wrong of course, and it could be it won't even work with
onenand.

Something to look later on for sure if anybody is interested.

Regards,

Tony