Re: barebox state is not fixed up into kernel-device-tree

["Ulrich Ölmann" <u.oelmann@pengutronix.de>]

Hi Patrick,

Patrick Boettcher <patrick.boettcher@posteo.de> writes:
> On Mon, 5 Nov 2018 09:41:51 +0100
> Patrick Boettcher <patrick.boettcher@posteo.de> wrote:
>> On Mon, 05 Nov 2018 09:28:53 +0100
>> Ulrich Ölmann <u.oelmann@pengutronix.de> wrote:
>> > Patrick Boettcher <patrick.boettcher@posteo.de> writes:
>> > > I'm using a device-state (for bootchooser) which is stored in an
>> > > eeprom.
>> > >
>> > > Works fine from within barebox - read and write.
>> > >
>> > > Userspace does not see the state:
>> > >
>> > >   Neither /aliases/state nor /state found
>> > >
>> > > The displayed device-tree when booting with 'boot -v -v <name>'
>> > > does not contain the state-entry.
>> > >
>> > > However, there is a warning of a failed fixup:
>> > >
>> > >   Failed to fixup node in of_state_fixup+0x1/0x1ac: No such device
>> > >
>> > > Could it be that the eeprom-alias is missing? I'm still learning
>> > > device-tree and stuff and I'm not yet entirely sure how everything
>> > > is related.
>> > >
>> > > The partition is created within a
>> > >
>> > >   &eeprom {
>> > >      [..]
>> > >   }
>> > >
>> > > section and eeprom is defined as
>> > >
>> > >   eeprom: eeprom@52 {
>> > >
>> > >   }
>> > >
>> > > (I added the 'eeprom: '- name/alias)
>> > >
>> > > Where am I missing the link?
>> >
>> > there was a patch recently that fixed a bug in the context of
>> > partition fixups and as a result repaired the state fixup as well
>> > for some setups:
>> >
>> >   http://lists.infradead.org/pipermail/barebox/2018-October/035091.html
>> >
>> > Please check if it solves your problem. If not then please provide
>> > more insight into your devicetrees (barebox & kernel) and post a
>> > little bit more context of the state node as well as the eeprom and
>> > the aliases nodes.
>>
>> I investigated further (still doing right now). In my kernel
>> device-tree the eeprom does not have the partition definition. So
>> of_state_fixup() does not find it (I added some debug prints to
>> analyze):
>>
>>    of_find_node_by_path_from:
>>        /soc/aips-bus@02100000/i2c@021a0000/eeprom@52/partitions/state@0
>>        not found
>>
>> I wrongly assumed from mails I found in the archive that barebox is
>> fixing up even the partitions.
>>
>> Does your patch from above will be helpful in my case?
>>
>> Do I need to change the kernel-device-tree to insert the partitions
>> manually? If so, how should it look like if the state-partition in
>> barebox is defined like this:
>>
>>   &eeprom {
>> 	status = "okay";
>> 	partitions {
>> 		compatible = "fixed-partitions";
>> 		#size-cells = <1>;
>> 		#address-cells = <1>;
>> 		backend_update_eeprom: state@0 {
>> 			reg = <0x0 0x100>;
>> 			label = "barebox-state-eeprom";
>> 		};
>> 	};
>>   };
>
> After adding the partition the kernel-device-tree
>
>   &eeprom {
> 	status = "okay";
> 	partitions {
> 		backend_update_eeprom: state@0 {
> 			reg = <0x0 0x100>;
> 		};
> 	};
>   };
>
> The barebox-fixup error disappear, the dumped device tree at boot-time
> contains the state-node.
>
> However, barebox-state, run from userspace gives
>
>   of_get_devicepath: no 'label' property found
>   in /soc/aips-bus@02100000/i2c@021a0000/eeprom@52/partitions/state@0
>   Cannot find backend path in /state
>
>
> Do I need to copy all of the partition-description into the
> kernel-device-tree? Is this, what your patch addresses?

The patch is needed to fix newer barebox releases, but you are using an
old vendor patched version where it is not needed.

It looks like no fixup for the eeprom partitions in the kernel
devicetree takes place. As an alternative to adding the partitions
manually you could probably patch your barebox to register the wanted
fixup in the driver.

Best regards
Ulrich
--
Pengutronix e.K.                           | Ulrich Ölmann               |
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