[U-Boot] [PATCH v2 3/4] arm: imx: m53evk: remove usage of mx53_dram_size

[Marek Vasut]

On 12/18/2017 11:47 AM, Patrick Brünn wrote:
>> From: Marek Vasut [mailto:marex at denx.de]
>> Sent: Montag, 18. Dezember 2017 10:17
>> On 12/18/2017 10:02 AM, linux-kernel-dev at beckhoff.com wrote:
>>> From: Patrick Bruenn <p.bruenn at beckhoff.com>
>>>
>>> Static variables are not available during board_init_f().
>>
>> They are, since the board runs from RAM at that point already.
>>
> From reading the README and common/board_f.c I got the impression,
> that dram_init() is called before it's save to access mx53_dram_size.
> And as that change seemed to cure the strange behavior I described
> in [1] and [2], I prepared a patch for my board, which ended up to be
> requested for m53evk and mx53loco, too.

Technically yes, board_init_f means it runs from FLASH and has no or
minimal storage available. On the MX53 with SPL, it's running from RAM
so it's safe to use static variables too.

>>> 'static uint32_t mx53_dram_size[2];' was used in board specific
>>> dram_init(), dram_init_banksize() and get_effective_memsize() to avoid
>>> multiple calls to get_ram_size().
>>>
>>> Reused dram initialization functions from arch/arm/mach-
>> imx/mx5/mx53_dram.c
>>>
>>> Signed-off-by: Patrick Bruenn <p.bruenn at beckhoff.com>
>>>
>>> ---
>>>
>>> Changes in v2: None
>>>
>>>
>>> Only compile tested with make m53evk_defconfig
>>
>> Are you sure this patch retains the original functionality ? Note the
>> warning ...
> 
> Effectively it changes:
>  -      return mx53_dram_size[0];
> +       return get_ram_size((void *)PHYS_SDRAM_1, 1 << 30);
> 
> So, yes I am convinced that get_effective_memsize() still returns only the size
> of the first dram bank.

I suspect that will fails on M53 due to it's split-bank configuration.
The board has two DRAM banks with a hole between them.

> However, I would be fine with just keeping the changes to my board (cx9020).
> And if anyone has a better idea of what might be the root cause of [1] and [2],
> I would absolute appreciate any input to that.

If your board also has two DRAM banks with a hole between them and you
can test if this works fine, then I'm OK with this change.

> Best regards and thanks in advance for any feedback,
> Patrick
> 
> [1] https://lists.denx.de/pipermail/u-boot/2017-November/313214.html
> [2] https://lists.denx.de/pipermail/u-boot/2017-December/314480.html
> 
> ---
> Beckhoff Automation GmbH & Co. KG | Managing Director: Dipl. Phys. Hans Beckhoff
> Registered office: Verl, Germany | Register court: Guetersloh HRA 7075
> 
> 


-- 
Best regards,
Marek Vasut