Re: [PATCH] ARM: shmobile: r8a7790: switch from scif to scifa

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Geert,

On Tuesday 30 September 2014 12:44:59 Geert Uytterhoeven wrote:
> On Tue, Sep 30, 2014 at 12:40 PM, Laurent Pinchart wrote:
> > On Tuesday 30 September 2014 13:30:29 Simon Horman wrote:
> >> On Fri, Sep 19, 2014 at 12:28:28PM +0900, Simon Horman wrote:
> >>> On Thu, Sep 18, 2014 at 10:57:12AM +0300, Laurent Pinchart wrote:
> >>>> On Thursday 18 September 2014 08:55:43 Simon Horman wrote:
> >>>>> On Wed, Sep 17, 2014 at 05:40:07PM +0300, Laurent Pinchart wrote:
> >>>>>> On Tuesday 16 September 2014 18:10:37 Wolfram Sang wrote:
> >>>>>>> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
> >>>>>>> 
> >>>>>>> SCIF and SCIFA can be plexed onto the same wires on Lager board.
> >>>>>>> The datasheet also describes the wires as SCIFA. So, to make use
> >>>>>>> of the bigger FIFOs switch to SCIFA instead.
> >>>>>>> 
> >>>>>>> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> >>>>>>> ---
> >>>>>>> 
> >>>>>>> Currently, I use this patch to check if the DMA RX issue is the
> >> >>>>> same on SCIF and SCIFA (yes, it is). However, I still think it
> >>>>>>> makes sense to use the bigger FIFOs. I will check this next week
> >>>>>>> with Bastian's FIFO patches. Until then, I send this as RFC to
> >>>>>>> collect opinions speaking for/against this change.
> >>>>>> 
> >>>>>> I have nothing against this change, but I believe the aliases should
> >>>>>> now be serial0 and serial1 to match the legacy code (OK, that's a
> >>>>>> lame excuse, we all know that I just want to change the aliases
> >>>>>> ;-)).
> >>>>> 
> >>>>> Thanks Laurent, I think its probably time we had that conversation
> >>>>> again. But I think that change can be done (or not ^) separately to
> >>>>> this change.
> >>>> 
> >>>> It could, but I believe it would make sense to do both in one patch,
> >>>> otherwise there will be a console serial port device mismatch between
> >>>> the legacy and multiplatform cases.
> >>> 
> >>> I'm a little confused.
> >> > Does this patch introduce such a miss-match?
> >> 
> >> Hi Laurent,
> >> 
> >> I'd like to move this forwards somehow.
> > 
> > This patch switches the Lager board to use SCIFA[01] instead of SCIF[01],
> > while keeping the Linux devices named /dev/ttySC[67]. With legacy boot,
> > SCIFA[01] are named /dev/ttySC[01]. There would thus be a mismatch in that
> > sense, even if this change doesn't prevent using the same Linux serial
> > devices on both legacy and DT boot.
> 
> So if I understand if correctly, booting with the current
> "console=ttySC6,115200"
> in /chosen/bootargs will give a working console for both legacy and
> multi-platform,
> but the underlying serial hardware block for the console differs (legacy
> uses SCIF0, multi-platform uses SCIFA0)?

As far as I understand that's correct.

-- 
Regards,

Laurent Pinchart