barebox-state setup

[Sascha Hauer]

On Tue, May 02, 2017 at 03:24:10PM +0200, Andreas Wilhelm wrote:
> Hello,
> 
> I am using barebox state to exchange data between barebox and linux. From barebox I can access and change the state without any problems. If I try to access the state using the barebox-state util included with dt-utils (v2017.03.0), I get the following error:
> 
> > # barebox-state -g myvar
> > of_get_devicepath: no 'label' property found in /soc/aips-bus at 02000000/spba-bus at 02000000/ecspi at 02008000/m25p80 at 0
> > Cannot find backend path in /state
> 
> This problem does not occur when using version 2016.08.0 of dt-utils. However, in this version I experienced an other problem. Even with backend-storage-type set to "circular" barebox attempted to storte data in "direct" mode:
> 
> > WARNING, no stridesize given although we use a direct file
> > write. Starting in degraded mode
> > Failed to initialize desired amount of direct buckets, only 1 of 3
> > succeeded
> 
> Furthermore changing the state from within barebox worked just fine, while changing it using dt-utils from within a booted linux didn't.
> 
> The barebox state is stored in NOR-flash and configured in barebox as followed:
> 
> > state: state {
> >     magic = <0x27031977>;
> >     compatible = "barebox,state";
> >     backend-type = "raw";
> >     backend = &flash, "partname:barebox-state";

Please use "backend = &barebox_state;" with a partition like this:

barebox_state: partition at 0 {
	reg = <0x0 0x40000>;
};

> Within the linux kernel I use the following configuration

Note that barebox will rewrite the state node in the device tree passed
to Linux to make sure that both are consistent. You do not need to add a
state node to the Linux device tree manually. Unfortunately the
rewriting of the device node does not work correctly if you use the
"partname:" binding above in barebox.

Sascha

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |