[meta-xilinx] [U-BOOT PATCH] zynq_common: Add uEnv.txt boot environment load support

[Nathan Rossi]

> -----Original Message-----
> From: Michal Simek [mailto:michal.simek at xilinx.com]
> Sent: Wednesday, September 04, 2013 2:42 PM
> To: Philip Balister
> Cc: Michal Simek; Nathan Rossi; git; meta-xilinx at yoctoproject.org;
> Jagannadha Sutradharudu Teki
> Subject: Re: [U-BOOT PATCH] zynq_common: Add uEnv.txt boot environment
> load support
>
> On 09/03/2013 09:43 PM, Philip Balister wrote:
> > On 09/02/2013 03:40 AM, Michal Simek wrote:
> >> Hi,
> >>
> >> On 08/30/2013 08:13 AM, Nathan Rossi wrote:
> >>> Add support for using a uEnv.txt file for loading and or modifying the
> >>> existing boot environment during a Zynq "sdboot". If the environment
> >>> fails to load during the "sdboot" continue booting from SD normally.
> >>>
> >>> This uEnv.txt and bootenv/uenv default environment variables are based
> >>> on the implementation used in omap3_beagle.h.
> >>>
> >>> Signed-off-by: Nathan Rossi <nathan.rossi at xilinx.com>
> >>> ---
> >>> Hi All,
> >>>
> >>> This is a feature that has been requested by some users of the meta-
> xilinx
> >>> layer. It is the additional of an optional 'uEnv.txt' boot environment
> file
> >>> which allows the modification of the SD boot. It is very useful for
> development
> >>> purposes and also in production environments. (There are also some
> specific
> >>> development boards that would greatly benefit from this, specifcally
> the
> >>> Parallella board which cannot directly boot from SD card due to its
> use of SD_1
> >>> instead of SD_0, this would make boot environment modifications
> significantly
> >>> easier)
> >>>
> >>> Philip has done an initial implementation of this feature see:
> >>> https://github.com/balister/meta-
> xilinx/commit/8b66cb1edb65c34c332888e907aec4333422af6b#L1R1
> >>>
> >>> However I would like to see this accepted into the u-boot-xlnx for the
> next
> >>> release. So I have reworked Philip's initial implementation (based on
> some
> >>> comments from Michal).
> >>>
> >>> When this is accepted into the master-next branch of u-boot-xlnx I
> will backport
> >>> it for use in the Yocto meta-xilinx layer.
> >>>
> >>> Regards,
> >>> Nathan
> >>> ---
> >>>  include/configs/zynq_common.h |   28 ++++++++++++++++++++++------
> >>>  1 file changed, 22 insertions(+), 6 deletions(-)
> >>
> >> Applied to the master-next.
> >
> > I built u-boot-2013.07 + this patch and it failed to ru the commands
> > from the uEnv.txt file until I increased the value of SYS_MAXARGS.
> >
>
> Nathan: Have you tested that patch?
>
> Thanks,
> Michal
>
>

Hi Michal,

Yes I tested the patch, however I did not test long environment variables which appears to be the issue that Philip has. This is the uEnv.txt he is using. https://github.com/balister/meta-xilinx/blob/boot-bin-1/recipes-bsp/u-boot/u-boot-xlnx/zedboard-zynq7/uEnv.txt-sd-boot

Which is not an issue with the uEnv commands, but merely an issue with environment variables in u-boot in general. Other platforms that use the uEnv.txt implementation tend to increase the CONFIG_SYS_MAXARGS definition to a value above the default but not all do.

omap3_beagle (which increases it to 32)
http://git.denx.de/?p=u-boot.git;a=blob;f=include/configs/omap3_beagle.h;h=c1245e7b841e1c633b217ba0daf933abe363df0f;hb=HEAD#l324
omap3_mvblx.h (which sets it to 16)
http://git.denx.de/?p=u-boot.git;a=blob;f=include/configs/omap3_mvblx.h;h=0c88419f245eff14a7b8cd2b3244fec6d05fc088;hb=HEAD#l220

Is 'CONFIG_SYS_MAXARGS' something that u-boot-xlnx would want to have increased, or does it affect the expectations of U-Boot to significantly?

Regards,
Nathan


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