Thread (15 messages) 15 messages, 5 authors, 2011-06-27
STALE5489d

[PATCH] omap3: beagle: Use GPTIMERi 1 for clockevents

From: tony@atomide.com (Tony Lindgren)
Date: 2011-06-27 10:14:28
Also in: linux-omap

* Paul Walmsley [off-list ref] [110625 15:42]:
On Sun, 26 Jun 2011, Premi, Sanjeev wrote:
quoted
[sp] I didn't include a reason - because the problem may not
     be reproducible on the public trees.

     During tests performed in internal development trees, the
     BogoMIPS calculations @ 1GHz wouldn't go beyond "830-850"
     range. While there was no such inconsistency on OMAP3EVM.
There are some other reasons to avoid GPTIMER12 when possible, which you 
should probably put in the patch description.  The most important, in my 
view, is that the clock source for GPTIMER12 is much less frequency-stable 
than the clock sources for GPTIMER1.  So using GPTIMER12 can result in 
major time skew over a fairly short interval.

I've been meaning to send a patch like this for some time, so I'm happy to 
see this fixed.
This fix will cause bad dependency issues with sys_timer.

This patch has a dependency to omap3_beagle_init_rev, which depends on
the mux framework and gpio framework. Not cool for init_early. We just
want to initialize sys_timer early without any complicated dependencies.

The best way to fix this is to set a separate machine ID for the properly
working beagle boards like xm, then just set the .timer entry to omap3_timer
for working beagle boards and omap3_secure_timer for non-working beagle
boards. The rest of the board-*.c file can be shared.

The above assumes the patches in devel-timer branch where we no longer
have the non-standard timer interface, but use the sys_timer entries
instead like we should.

Regards,

Tony
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