[U-Boot] user-space ===>> U-Boot ====>> user-space ?
Wolfgang Denk
wd at denx.de
Tue Oct 12 07:16:30 CEST 2010
Dear bosmith,
In message <29939469.post at talk.nabble.com> you wrote:
>
> Is there a simple way to send data from a Linux user-space program to
> U-Boot?
> How about from U-Boot up to a user-space program?
I know of two communication methods:
Using the environment (and fw_printenv/fw_setenv in Linux user space),
and using a shared log buffer (which may be a bit difficult to read /
process in U-Boot if that should be needed).
> The data may change often enough that using fw_printenv and fw_setenv might
> wear out the NAND storage area for the environment.
Then put all this stuff in a UBI partition, and use the "env import" /
"env export" features in U-Boot to access it (or extend the code to
handle environment in a UBI partition directly).
> The use-case is to have two kernel images, two root file systems, and to let
> a user-space application specify which to use and then force a reboot. The
> system will not lose power during this reboot.
And you think you will switch betweent these two so often that using
the environment would wear out the NAND? I think you are too
pessimistic.
> This seems like a common enough problem. Has anyone solved it before?
Most people use the environment for this purpose.
Best regards,
Wolfgang Denk
--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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