[U-Boot] [PATCH] mx6qsabresd: Add basic support

[stefano babic]

Am 14/04/2012 22:13, schrieb Wolfgang Denk:
> Dear Stefano,
> 
> In message <4F898CA5.8070308 at denx.de> you wrote:
>>
>> The start address CONFIG_SYS_MEMTEST_START is the lowest address of the
>> SDRAM that can be accessed, that is MMDC0_ARB_BASE_ADDR (0x10000000) for
>> i.MX6.
> 
> But it _should_ be the lowest address that can _safely_ be used for
> such tests, i. e. the range MEMTEST_START - MEMTEST_START must neither
> contain the exception vectors, not U-Boot's code, stack or malloc arena.
> 
>> dynamically, also the last RAM address that can be tested should be
>> computed at run time and not at compile time with CONFIG_SYS_MEMTEST_END.
> 
> CONFIG_SYS_MEMTEST_END is NOT the end of physical RAM, but the end of
> the range that can be tested without crashing U-Boot...

Well, but why do we have to define at compile time this value, that in
most cases can be wrong ? Why should "mtest" use a default value if not
all parameters are passed ? IMHO it is better if mtest returns with an
error if end address is not provided.

> 
> Such a patch would be wrong.

Really I think it is better to get rid completely of
CONFIG_SYS_MEMTEST_START and CONFIG_SYS_MEMTEST_END without trying to
make some (maybe wrong) assumptions, and let mtest doing its job

Best regards,
Stefano Babic

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