Re: [PATCH v8 07/16] drivers: reset: Add STM32 reset driver

Maxime Coquelin
2015-05-22T14:04:33Z

2015-05-22 0:01 GMT+02:00 Andreas Färber <afaerber@suse.de>:
> Am 21.05.2015 um 21:57 schrieb Maxime Coquelin:
>> Note that for now, I still use your bootloader.
>> I have done the changes to reset the timers in the afboot-stm32.
>> That's the reason why I asked you under which licence it is delivered
>> few months ago.
>
> Sorry, too many mails... The stm32 one is GPL-2.0, as parts of it were
> derived from a U-Boot fork. (Personally I prefer GPL-2.0+; fm4 and
> xmc4000 are MIT/X11.)

Not a problem, thanks for providing the licence.

>> I can share you the patch if you want, even if I understand it is more
>> about the concept that you are reluctant.
>>
>> On my side, I plan to move to U-Boot soon, as Kamil Lulko added STM32
>> support in mainline [1].
>
> You're free to use any bootloader you like, but you will find it
> difficult to build in USB etc. drivers given the sheer size of U-Boot.
> That was my motivation for writing the tiny one. ;)

I think the two bootloaders make sense. Indeed, using U-Boot restricts
the size of the Kernel.
I also have the stm32429i-eval board, with 32MB NOR and 32MB SD-Ram.
At least on this one I will use U-Boot, as tftp could be used to load
Kernel since it has Ethernet port.

>> In case of U-Boot, the timer reset should be de-asserted when jumping
>> into the Kernel, as Rob mentionned [0].
>
> Thanks, I've updated the xmc4000 one accordingly and can do the same for
> stm32. But you are right that I consider that an ugly workaround,
> although on the other hand my earlyprintk patches also depend on the
> bootloader setting up GPIOs and UART.

Yes, the Kernel always need to rely on the bootloader to provide a
minimal setup (clock/ddr/muxing...).

Regards,
Maxime