[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <1b7064bc-7008-2c1c-2398-143401bbc368@suse.de>
Date: Wed, 25 Jul 2018 00:15:44 +0200
From: Andreas Färber <afaerber@...e.de>
To: linux-mips@...ux-mips.org
Cc: Ralf Baechle <ralf@...ux-mips.org>,
Paul Burton <paul.burton@...s.com>,
James Hogan <jhogan@...nel.org>, linux-kernel@...r.kernel.org,
Ian Pozella <Ian.Pozella@...tec.com>,
James Hartley <james.hartley@...drel.com>,
Rahul Bedarkar <rahulbedarkar89@...il.com>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>, devicetree@...r.kernel.org
Subject: Re: [PATCH 04/15] MIPS: dts: img: pistachio_marduk: Switch mmc to 1
bit mode
Am 22.07.2018 um 23:19 schrieb Andreas Färber:
> From: Ian Pozella <Ian.Pozella@...tec.com>
>
> The mmc block in Pistachio allows 1 to 8 data bits to be used.
> Marduk uses 4 bits allowing the upper 4 bits to be allocated
> to the Mikrobus ports. However these bits are still connected
> internally meaning the mmc block recieves signals on all data lines
"receives"
I had fixed a number of typos from the downstream patches already, but
this one slipped through.
Regards,
Andreas
> and seems the internal HW CRC checks get corrupted by this erroneous
> data.
>
> We cannot control what data is sent on these lines because they go
> to external ports. 1 bit mode does not exhibit the issue hence the
> safe default is to use this. If a user knows that in their use case
> they will not use the upper bits then they can set to 4 bit mode in
> order to improve performance.
>
> Also make sure that the upper 4 bits don't get allocated to the mmc
> driver (the default is to assign all 8 pins) so they can be allocated
> to other drivers. Allocating all 4 despite setting 1 bit mode as this
> matches what is there in hardware.
>
> Signed-off-by: Ian Pozella <Ian.Pozella@...tec.com>
> Signed-off-by: Andreas Färber <afaerber@...e.de>
[snip]
--
SUSE Linux GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Powered by blists - more mailing lists