[U-Boot] [PATCH 5/8] arm: Add boottime support for the ARM architecture

Wolfgang Denk wd at denx.de
Thu Nov 22 14:04:30 CET 2012


Dear Lee Jones,

In message <20121122101433.GA4328 at gmail.com> you wrote:
> Let's try to move this forward.

Actually you don't.  You insist on not changing anything on your side,
and ask others to adapt to it.

> Okay, to summarise so far:
> 
> 1. Bootloader and kernel mechanisms should be the same
> 
> So putting bootloader tracepoints in the bootlog and the kernel's
> in an internal data structure is not acceptable, as it would add
> too much extra overhead to link them together and parse.

OK.  But this appears a new requirement - your original implementation
did not bother about this, using ATAGs here and somethign else
there...

> 2. The kernel bootlog is not the correct place for tracepoints
> 
> If we were to adhere to point No1 and bootloader & kernel
> entries would be placed into the bootlog; no self respecting
> kernel engineer/maintainer will allow 100's of spurious
> tracepoint entries in the kernel log, regardless of log level.

I wonder about the self-assuredness you speak for all of them.  Has
this been dicussed in full context before?

> Actually, putting it in DT has lots of advantages. 1) DT works
> cross-architecture and cross-platform, so your architecture
> independent box is inherently ticked 2) DT already carries
> non-hardware specific information such as the kernel cmdline.
> I don't see how adding <10 (but would more likely to be 2-3)
> tracepoint entries would completely break convention. We can
> either get the kernel driver to scrub the entries if you'd be
> that offended by keeping them in.

Hm... in accordance to No. 1 above your kernel code will add new
entries to the device tree while the kernel is booting?  So instead of
"adding <10" it now will be adding "100's of spurious tracepoint
entries" to the DT?

Are you sure this is a good idea?  [Not considering if it's actually
possible.]

But then, if you drop item 1, then what's wrong with "<10 (but would
more likely to be 2-3)" additional log messages?


Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
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Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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