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SubjectRe: [PATCH v2 2/3] microblaze: remove redundant early_printk support
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On 13.4.2018 16:11, Rob Herring wrote:
> On Tue, Apr 10, 2018 at 8:44 AM, Michal Simek <michal.simek@xilinx.com> wrote:
>> Hi Rob,
>>
>> On 28.3.2018 04:06, Rob Herring wrote:
>>> With earlycon support now enabled, the arch specific early_printk support
>>> can be removed.
>>
>> earlycon is not the full replacement of early_printk support as is
>> designed right now.
>> Definitely current early_printk is pretty old and contains code
>> duplication but it starts much earlier then earlycon.
>
> Yes, essentially it's after MMU enabling rather than before. But it is
> still before any h/w specific setup (dependent on the DT) which is
> where one would typically fail to boot. Generally, I've found before
> DT unflattening to be early enough. What can go wrong at this early
> stage? Memory is flaky or you've passed in bad memory ranges or image
> locations. An earlier console may or may not help there and those
> problems are easier to debug in the bootloader.
>
> So it is a question of what you want to maintain.
>
>>> Signed-off-by: Rob Herring <robh@kernel.org>
>>> Cc: Michal Simek <monstr@monstr.eu>
>>> ---
>>> v2:
>>> - Fix booting. The setup_memory call needed to be before the
>>> parse_early_param call.
>>
>> What's the reason for calling setup_memory before parse_early_param?
>> Is there any dependency?
>
> Yes, either fixmap or ioremap (in your case) has to be functional when
> earlycon is setup which happens via parse_early_param.

Ok. Let's add it and see if there is any issue. Do you have any code
which depends on this series?

Thanks,
Michal


--
Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel - Xilinx Microblaze
Maintainer of Linux kernel - Xilinx Zynq ARM and ZynqMP ARM64 SoCs
U-Boot custodian - Xilinx Microblaze/Zynq/ZynqMP SoCs


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