Question about uboot initialisation

[Simon Glass]

Hi Momo,

On Sun, 11 Sept 2022 at 08:29, momo aubin <aubinno at gmail.com> wrote:
>
> Hi Simon,
>
> Thanks for getting back to me.
>
> How can I avoid top posting ? i'm a new

You can do a web search for "top posting" which explains the issue
better than I can.

>
> How uboot know that the kernel has started ?

Generally it does not. U-Boot's job is typically over once it jumps to
the kernel.

> If the system is blocked during the u-boot stage, is it possible to restart all the systems ?
> It is possible to put a timer in the u-boot stage in case of the kernel has not started , can the system reboot by choosing another u-boot ?

You can use a watchdog timer to reboot the system. It can be set up in
U-Boot, then it Linux does not kick it in time, it will cause a
reboot. To choose another U-Boot, you would need to do some scripting,
or use mender. There is some work on VBE going on (U-Boot standard
boot) but it will take a while to all land.

Regards,
SImon


>
>
> Thanks for your answer in advance.
> Aubin
>
>
> On Tue, 30 Aug 2022 at 04:30, Simon Glass <sjg at chromium.org> wrote:
>>
>> Hi Aubin,
>>
>> On Mon, 29 Aug 2022 at 01:40, momo aubin <aubinno at gmail.com> wrote:
>> >
>> > Hi Simon,
>> > I got what is the 'dm tree' which is a driver model. This command could be done only in uboot stage. but i got the situation in which the initialisation of u-boot has not finished yet as showing in the following picture.
>> >
>> >
>> >  .i would like to know what is wrong in the initialisation ?
>>
>> Please try to avoid top posting.
>>
>> I think the best thing is to move to the latest U-Boot. You are about
>> 9 years behind! But as to your question, I am really not sure. If it
>> is a TI board, you could try asking them?
>>
>> Regards,
>> Simon
>>
>>
>> >
>> > Best Regard,
>> > Aubin
>> >
>> > On Mon, 29 Aug 2022 at 05:24, momo aubin <aubinno at gmail.com> wrote:
>> >>
>> >> Hi Simon,
>> >>
>> >> Thanks for your answer.
>> >>
>> >> The script that you are telling it is Env.txt right ?
>> >>
>> >> What is a 'dm tree' ? Please could you provide me more infos about this ?
>> >>
>> >> Thanks for your answer in advance.
>> >>
>> >> On Sat, 27 Aug 2022 at 02:21, Simon Glass <sjg at chromium.org> wrote:
>> >>>
>> >>> Hi Aubin,
>> >>>
>> >>> On Fri, 26 Aug 2022 at 06:41, momo aubin <aubinno at gmail.com> wrote:
>> >>> >
>> >>> > Dear all,
>> >>> >
>> >>> >
>> >>> > Is there any way that allows us to know that uboot has initialised all his
>> >>> > peripherals before starting loading kernel ?
>> >>> >
>> >>> > The goal of this check is to reset the board in case of bad initialisation
>> >>> > and choose a different uboot .
>> >>> >
>> >>> > Thanks for your answer in advance.
>> >>> > Aubin
>> >>>
>> >>> If there is a failure then it likely results in an error-return code
>> >>> from board_init_f() or board_init_r(). These generally halt U-Boot /
>> >>> cause a reboot. But this only covers the peripherals that U-Boot sets
>> >>> up early, like serial, clocks, pinctrl, MMC, PCI, etc.
>> >>>
>> >>> U-Boot typically does not init a peripheral unless it is needed for U-Boot.
>> >>>
>> >>> While U-Boot is running (e.g. a script) it may start up other
>> >>> peripherals (e.g. to read a kernel from USB) and in those cases errors
>> >>> can be handled by the script.
>> >>>
>> >>> You can use 'dm tree' to see what devices have been probed successfully.
>> >>>
>> >>> Regards,
>> >>> Simon