[U-Boot] [PATCH v2 3/3] common: Generic loader for file system

[Marek Vasut]

On 06/11/2018 02:42 PM, Chee, Tien Fong wrote:
> On Mon, 2018-06-11 at 13:55 +0200, Marek Vasut wrote:
>> On 06/11/2018 01:53 PM, Chee, Tien Fong wrote:
>>>
>>> On Mon, 2018-06-11 at 11:39 +0200, Marek Vasut wrote:
>>>>
>>>> On 06/11/2018 07:01 AM, Chee, Tien Fong wrote:
>>>> [...]
>>>>>
>>>>>
>>>>>>
>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> This is a configuration. You do not need (new) a DT
>>>>>>>> compatible
>>>>>>>> for
>>>>>>>> that.
>>>>>>>> So why is the DT compatible even needed in the FW loader
>>>>>>>> at
>>>>>>>> all ?
>>>>>>>>
>>>>>>> I thought DT compatible is used by driver to find the
>>>>>>> fs_loader
>>>>>>> node in
>>>>>>> DTS. May be i am wrong.
>>>>>> There should be no FW loader in the DTS. Why would there be
>>>>>> one ?
>>>>>>
>>>>>  I added DTS support for user to define storage type and
>>>>> default
>>>>> partition. So you want me to remove the DTS?
>>>>> Removing the DTS, then user can only set storage type and
>>>>> partition
>>>>> through dev instance. So, this design OK for you?
>>>> How does Linux do it ?
>>>>
>>> Linux firmware loading method is different with this
>>> Linux loading firmware with
>>> 1. Firmware search paths - which is hardcoded in root file system
>>> 2. Built-in firmware - part of kernel binaries
>>>
>>> This patch loading firmware with
>>> 1. Storage type and partition specified in DTS, but storage type
>>> can
>>> be overridden dev instance and partition through U-boot variable
>>> environment.
>>>
>>> Or:
>>>
>>> 2. Storage type can be set through dev instance, and partition
>>> through
>>> U-boot variable environment. No DTS is required.
>> And why can we not do as Linux does ?
>>
> Because we don't have root file system, but i have mimicked the search
> path in our variable environment, but with both storage type and
> partition.

OK, so user can configure environment variable to inform U-Boot where to
look for firmware, good (although, this probably fails in early env,
dunno of that's a problem).

But why do we need the DT part of things ? I don't think we do need it
at all.

-- 
Best regards,
Marek Vasut