[U-Boot] [PATCH 0/11] MIPS: bootm updates

[Daniel Schwierzeck]

2013/6/25 Daniel Schwierzeck <daniel.schwierzeck at gmail.com>:
> Hi Thomas,
>

oops, I hit the send key too early

> Am 21.06.2013 21:59 schrieb "Langer Thomas (LQDE RD ST PON SW)"
> <thomas.langer at lantiq.com>:
>
>
>>
>> Hello Daniel,
>>
>> sorry for being late with my questions.
>>
>> Daniel Schwierzeck wrote on 2013-06-09:
>> >   MIPS: bootm: refactor initialisation of kernel cmdline
>> >   MIPS: bootm: refactor initialisation of kernel environment
>> >   MIPS: bootm: make initialisation of Linux environment optional
>> >   MIPS: bootm: add support for generic relocation of init ramdisks
>> >   MIPS: bootm: automatically initialise kernel cmdline variable 'mem'
>> >   MIPS: bootm: automatically initialise kernel cmdline variables
>> > 'rd_start' and 'rd_size'
>>
>> These patches changing the style, how parameters are given to the kernel
>> (using cmdline instead of environment)
>
> The environment is still available
>
>>
>> Can you explain a little, why this is necessary?
>> Please give some references to the corresponding kernel changes or
>> discussions, if possible.
>
> the current U-Boot kernel interface emulates the YAMON interface. But almost
> all boards supported by the kernel are bootloader agnostic or don't use
> U-Boot.

The generic kernel interface for mem and initramfs is either commandline or
device tree. IMHO it makes no sense to add bootloader specific code like
environment parsing to the kernel. So I want to support the generic interfaces
in U-Boot. The old environment code is still available.

>
>>
>> And how about backward compatibility? Will it still be possible to boot
>> older kernels?

I had no problems in my tests. Also a Lantiq BSP kernel boots fine.

>>
>> When you automatically add  the variable 'mem', will it still be possible
>> to override the memory size by manually adding it to the bootargs?
>>

I think you are referring to Lantiq's way of passing memory sizes for
voice firmware
to the kernel. Indeed this won't work anymore. I can add an additional
if condition around
the automatic code. Anyway I think it is better to always pass the
full memory size to
the kernel and reserve firmware memory by allocating contiguous DMA memory.
Then there is no need for propietary or bootloader-specific boot interfaces.

--
Best regards,
Daniel