[linuxsh-dev] [PATCH] better module clock calibration

[Philipp R. <pr...@pa...>]

I just submitted a patch to sourceforge that changes our clock calibration
mechanism to calibrate the timer clock rather than the CPU clock;  this
means it is more portable now (no assembly, and no CPU-specific constant);
it's also much faster (1/128 - 1/64 second rather than 1 - 2 seconds),
while not losing a lot of accuracy.

The original version also included a version of gettimeoffset, but the one
SUGIOKA Toshinobu has written at the same time as I is nicer.

There is also a very slight bugfix which I would like to paste here:

        /* Start TMU0 */
+       ctrl_outb(0, TMU_TSTR);
        ctrl_outb(TMU_TOCR_INIT, TMU_TOCR);
        ctrl_outw(TMU0_TCR_INIT, TMU0_TCR);
        ctrl_outl(interval, TMU0_TCOR);

Without this, the kernel wouldn't boot correctly if TMU0 was already
started.  Since head.S says:

 *   Hardware (including on-chip modules) may or may not be initialized. 

this sounds like the right thing to do to me.

The updated version of the patch (against current CVS) is attached.