[U-Boot] [PATCH 1/3] i.MX6: mx6qsabrelite: add CONFIG_REVISION_TAG

[Eric Nelson <eric.nelson@boundarydevices.com>]

On 03/04/2012 01:59 PM, Marek Vasut wrote:
>> On 03/02/2012 03:59 PM, Marek Vasut wrote:
>>>>    Freescale 2.6.38 (Non-DT) kernels require the revision atag to
>>>>    enable the VPU.
>>>>
>>>> Signed-off-by: Eric Nelson<eric.nelson@boundarydevices.com>
>>>> ---
>>>>
>>>>    board/freescale/mx6qsabrelite/mx6qsabrelite.c |    7 +++++++
>>>>    include/configs/mx6qsabrelite.h               |    1 +
>>>>    2 files changed, 8 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/board/freescale/mx6qsabrelite/mx6qsabrelite.c
>>>> b/board/freescale/mx6qsabrelite/mx6qsabrelite.c index db1bea9..590030b
>>>> 100644
>>>> --- a/board/freescale/mx6qsabrelite/mx6qsabrelite.c
>>>> +++ b/board/freescale/mx6qsabrelite/mx6qsabrelite.c
>>>> @@ -215,6 +215,13 @@ int board_mmc_init(bd_t *bis)
>>>>
>>>>    }
>>>>    #endif
>>>>
>>>> +#ifdef CONFIG_REVISION_TAG
>>>> +u32 get_board_rev(void)
>>>> +{
>>>> +	return 0x63000 ;
>>>> +}
>>>> +#endif
>>>> +
>>>>
>>>>    #ifdef CONFIG_MXC_SPI
>>>>    iomux_v3_cfg_t ecspi1_pads[] = {
>>>>
>>>>    	/* SS1 */
>>>>
>>>> diff --git a/include/configs/mx6qsabrelite.h
>>>> b/include/configs/mx6qsabrelite.h index 93000f0..85f6f7a 100644
>>>> --- a/include/configs/mx6qsabrelite.h
>>>> +++ b/include/configs/mx6qsabrelite.h
>>>> @@ -33,6 +33,7 @@
>>>>
>>>>    #define CONFIG_CMDLINE_TAG
>>>>    #define CONFIG_SETUP_MEMORY_TAGS
>>>>    #define CONFIG_INITRD_TAG
>>>>
>>>> +#define CONFIG_REVISION_TAG
>>>
>>> I think you can avoid this define altogether, you're using it anyway.
>>
>> Hi Marek,
>>
>> I'm not sure I understand.
>>
>> I need to define CONFIG_REVISION_TAG in order to get bootm to add
>> the tag:
>> 	http://git.denx.de/?p=u-
> boot.git;a=blob;f=arch/arm/lib/bootm.c;h=afa0093df
>> 7620606ee12b4dc1dd2ee37adee347c;hb=master#l137
>>
>> I made get_board_rev() conditional so we can get rid of it if (once)
>> we're only using DT kernels.
>
> You have CONFIG_REVISION_TAG set unconditionally, so you don't need the macro
> around that get_revision() function. I might be wrong.
>

You're right. Its just that I did that deliberately so you can save the
(admittedly) small amount of code by editing mx6qsabrelite.h.

Since U-Boot doesn't really have a configuration step, I find that
folks tend to tweak the board configuration file quite a bit based
on their needs.

Though it's a bit of a hack, we even formalized it on our i.MX5x products
to allow customers to keep their git repositories clean:
	http://boundarydevices.com/blogs/customizing-u-boot-on-i-mx