[U-Boot] spl: add size check including devicetree

[Simon Goldschmidt]

Am 22.03.2019 um 14:03 schrieb Tom Rini:
> On Fri, Mar 01, 2019 at 10:34:17PM +0100, Simon Goldschmidt wrote:
> 
>> Current linker based size checks do not account for the devicetree,
>> as this is added after linker stage.
>>
>> This patch moves the logic behind U-Boot proper BOARD_SIZE_CHECK
>> into a common function that is called for SPL, too.
>>
>> For SPL, CONFIG_SPL_MAX_SIZE is used to check u-boot-spl-dtb.bin.
>>
>> This is RFC for two reasons:
>> - scripts/Kbuild.include might not be the perfect place for this
>>    new function but was the only place I found included by both
>>    /Makefile and /scripts/Makefile.spl
>> - CONFIG_SPL_MAX_SIZE at least for some boards defines the size
>>    of the initially available SRAM. However, this check checks the
>>    SPL binary only. Initial SRAM must hold gd, heap and stack in
>>    addition to that.
>>
>> Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>
> 
> So, a problem is that we need to get at values after they've been
> pre-processed:
> /bin/sh: 1: printf: (SRAM_SCRATCH_SPACE_ADDR - CONFIG_SPL_TEXT_BASE): expected numeric value
> spl/u-boot-spl-dtb.bin exceeds file size limit:
>    limit:  0 bytes
>    actual: 124970 bytes
>    excess: 124970 bytes
> ../scripts/Makefile.spl:266: recipe for target 'spl/u-boot-spl-dtb.bin' failed

Right. We could run the define through libt/asm-offsets.c (just like 
GENERATED_GBL_DATA_SIZE is created), but how would we get the result 
back into the Makefile?

Regards,
Simon