[linuxsh-dev] Re: [linux-sh:01327] a patch for kernel/time.c

[Jesper S. <js...@re...>]

>>>>> "ebihara" == ebihara  <ebi...@si...> writes:

ebihara> hello all.  time.c didn't work well for detecting busclock
ebihara> and moduleclock.  so i made a patch for 'time.c'. (sh3 only)

This is the wrong approach. Well, it may work for your board, but may
mess up other boards.

I've just done a rewrite of the clock setup configuration in eCos,
supporting 7707, 7708, 7709A and 7729. And let me tell you, it's
seriously non-trivial to get right. And I have the benefit of being
able to rely on a compile time configuration to get it right.

IMO it's a serious mistake that the CPUs don't include a version
register of some sort so they can be properly identified at runtime
[does anybody know of a non-documented version register, by any
chance?]. Add to that some way to figure out which clock mode the CPU
is configured to use, and it would actually be possible to compute all
the magic at run time.

As it is, the clock setup code in Linux needs a very careful
rewrite. And no, I'm not volunteering just now :) Some rainy Sunday,
maybe.

Btw, I know that David Woodhouse fixed something in the clock
calibration code for SH. I'll try to get around to fishing out that
patch some time this week and submit it for inclusion in the Linux/SH
kernel.

Jesper