Howto implement bootchooser <-> rauc interaction

[Ahmad Fatoum]

Hello Konstantin,

On 22.12.21 15:05, Konstantin Kletschke wrote:
> I switched from doing the state in the onboard EEPROM (as said, it
> is write protected in production use) to save the state in a dead space
> in the onboard eMMC chip between MBR and first partition:
> 
> / {
> 	aliases {
> 		state = &state_eeprom;
> 	};
> 
> 	state_eeprom: state_eeprom {
> 		#address-cells = <1>;
> 		#size-cells = <1>;
> 		compatible = "barebox,state";
> 		magic = <0xcafebabe>;
> 		backend-type = "raw";
> 		backend = <&backend_state_mmc2>;
> 		backend-storage-type = "direct";
> 		backend-stridesize = <54>;
> 		last_chosen {

Here last_chosen is toplevel.


> Compiled in (relevant) variables:
> 
> * boot.default: bootchooser insidem2m_1 insidem2m_2
>   boot.watchdog_timeout: 0
>   bootchooser.default_attempts: 3
>   bootchooser.default_priority: 1
>   bootchooser.disable_on_zero_attempts: 0
>   bootchooser.reset_attempts:  (list: "power-on", "all-zero")
>   bootchooser.reset_priorities: 
>   bootchooser.retry: 0
> * bootchooser.state_prefix: state

Here you say they are inside state.*

> The userspace is no amused, however:
> 
> rauc status output:
> 
> (rauc:583): rauc-WARNING **: 18:51:57.389: Failed getting primary slot: Failed getting primary slot: No content to read

Yes RAUC has:

  #define BOOTSTATE_PREFIX "bootstate"

So that's what you need to use.

> barebox-state:
> 
> last_chosen=2
> system0.remaining_attempts=0
> system0.priority=21
> system0.ok=0
> system1.remaining_attempts=2
> system1.priority=20
> system1.ok=0

But state works correctly regardless, you can place
all sort of stuff there.

> ################ PLAN B ##################
> 
> I had a previous state device tree setup, which made userspace happy,
> but not barebox. I had a parent bootstate section containing system0 and
> system1:
> 
> / {
> 	aliases {
> 		state = &state_eeprom;
> 	};
> 
> 	state_eeprom: state_eeprom {
> 		#address-cells = <1>;
> 		#size-cells = <1>;
> 		compatible = "barebox,state";
> 		magic = <0xcafebabe>;
> 		backend-type = "raw";
> 		backend = <&backend_state_mmc2>;
> 		backend-storage-type = "direct";
> 		backend-stridesize = <54>;
> 		bootstate {

Here you have a correctly named container.

> With this device tree barebox bootschooser is unhappy:

Did you set bootchooser.boot_prefix?

> But userspace is fine:

As expected.

> I assume this has to do with bootchooser.state_prefix. If I change from
> state to bootstate (yes, brute force) I get:
> 
> global excerpt:
> 
> * bootchooser.state_prefix: bootstate
> 
> devinfo state looks the same as previous.
> 
> boot:
> 
> barebox at TI AM335x BeagleBone black:/ boot
> ERROR: bootchooser: Cannot get state 'bootstate'
> Nothing bootable found on 'bootchooser'
> Booting entry 'insidem2m_1'
> ext4 ext40: EXT2 rev 1, inode_size 256, descriptor size 64
> mounted /dev/mmc1.1 on /mnt/mmc1.1
> [...]
> 
> 
> 
> When I set:
> 
> * bootchooser.state_prefix: state.bootstate
> 
> I get best of both worlds!

Exactly. :-)

> Wall of text, two questions:
> 
> Is this resulting setup (DT with bootstate parent, state_prefix:
> state.bootstate) sane?

Ye, the final setup looks good now.

> Can the variant without the boostate variant work too? If it was the
> other way around, userspace working w/o the bootstate variant but bnot
> _with_ I would say additional configuration required or something, but
> this way... I would like to understand this fully.

RAUC hardcodes bootstate, so that's what you need to use, unless you patch
RAUC.

Cheers,
Ahmad

> 
> 
> Kind Regards
> Konstantin
> 
> 


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