[U-Boot] [PATCH] ARM: rpi: Add CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG support

[Guillaume Gardet <guillaume.gardet@free.fr>]

Le 19/08/2015 05:14, Stephen Warren a ?crit :
> On 08/18/2015 08:03 AM, Guillaume GARDET wrote:
>> Add CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG support to set 'board_rev' and
>> 'board_name' envs.
> That states what the patch does rather than why its useful to do it. Can
> you expand on why it's useful to set these variables?

Using boot scripts you may need to get the board version / revision infos, for example to select the right DTB since u-boot DTB names and kernel DTB files do not match.

>
>> diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
>> @@ -240,6 +240,12 @@ int misc_init_r(void)
>>   {
>>   	set_fdtfile();
>>   	set_usbethaddr();
>> +#ifdef CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
>> +	char str_rev[11];
>> +	sprintf(str_rev, "0x%X", rpi_board_rev);
>> +	setenv("board_rev", str_rev);
>> +	setenv("board_name", models[rpi_board_rev].name);
>> +#endif
>>   	return 0;
>>   }
> That adds a variable declaration in the middle of code. I'd suggest
> moving the new code into set_board_info() (a name that some other
> boards/SoCs that honor CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG use), and
> calling that function inside the ifdef in misc_init_r(). You can always
> make the function static and implement it before misc_init_r() so that
> the compiler is likely to inline it.

Ok, will do that.

>
> I'm not sure that models[rpi_board_rev].name contains values that are
> useful to place into an environment variable. It depends what you expect
> to do with that variable. Note that the values are not unique, and
> contain spaces, which might make the value hard to use and/or not
> reliable to differentiate between all the different types of boards.
>
> Conceptually I have no general objection to this patch, although I am a
> little worried about turning the board_name variable into some kind of ABI.
>

board_name variable should be considered to get a pretty board info print, not any kind of ABI. If people need to differentiate boards revs, just use board_rev variable.


Guillaume