[U-Boot] [PATCH] ARM: socfpga: Assure correct ACTLR configuration

[Marek Vasut]

On 05/31/2018 12:00 PM, Marek Vasut wrote:
> On 05/31/2018 11:52 AM, See, Chin Liang wrote:
>> On Tue, 2018-05-29 at 18:39 +0200, Marek Vasut wrote:
>>> Make sure the ARM ACTLR register has correct configuration, otherwise
>>> the Linux kernel refuses to boot. In particular, the "Write Full Line
>>> of Zeroes" bit must be cleared.
>>>
>>> Signed-off-by: Marek Vasut <marex at denx.de>
>>> Cc: Chin Liang See <chin.liang.see at intel.com>
>>> Cc: Dinh Nguyen <dinguyen at kernel.org>
>>> ---
>>> NOTE: This gem was well hidden in the Altera U-Boot fork and is
>>> really needed.
>>>       What is not entirely clear to me is WHY ? So why is this needed
>>> ?
>>
>> I vaguely recall it's related to HW constrain. And check back the
>> downstream U-Boot, actually we need to set the bit instead clearing
>> it. https://github.com/altera-opensource/u-boot-socfpga/blob/socfpga_v2
>> 014.10_arria10_bringup/arch/arm/cpu/armv7/socfpga_arria10/pl310.c
> 
> You are clearing it here:
> https://github.com/altera-opensource/u-boot-socfpga/blob/socfpga_v2014.10_arria10_bringup/arch/arm/cpu/armv7/socfpga_arria10/lowlevel_init.S#L35
> 
> The PL310 configuration is a different register. What HW constraint ?
> I'd really like to understand this problem.

Bump ? I had a report the register even has to be set to 0 , otherwise
there are ethernet problems. What is going on with this register ?

-- 
Best regards,
Marek Vasut