Re: [PATCH] MIPS: add support for gzip/bzip2/lzma compressed kernel images

[Ralf Baechle <ralf@linux-mips.org>]

On Mon, Aug 10, 2009 at 04:53:09PM +0200, Ithamar R. Adema wrote:

> Ralf Baechle wrote:
>> Printing is hardware specific; the debug code will need to be changed for
>> practically every MIPS platform on the planet, so I'm not too fond of the
>> idea unless somebody comes up with a cleaner infrastructure to do so.
>> Unfortunately we're not setup very well to do configuration detection etc.
>> in that debug code without adding tons of baggage.
>>   
> Would mimicing the uncompress.h header as used in the ARM architecture  
> be an idea? Maybe have one that does nothing in mach-generic and let the  
> machines that want debug output define their own that actually does IO.
>
> Just a header, defining putc()-ish functions, most architectures already  
> have code for that, so it should be trivial for them to implement it, if  
> wanted...
>
> Just an idea...

Oh, I wasn't trying to kill the debug code entirely but pointing out some
difficulties.  For some platforms the code would be a little larger and
more complex.  It could be as bad as dynamically detecting a console and
running PPP to talk to it.  Or having to carry fonts along and render
output into a complex graphics card.  but we can still deciede if the
feature is useful enough on a per platform base.

An implementation would probably look something like you pointed out
though I haven't seen the ARM header you mentioned.  Ideally code could
be shared with early printk.

  Ralf