Re: LTTng for SH architecture

Mathieu Desnoyers wrote:
> I recommend that you look at the "lttng instrumentation" patches for
> each architectures. You'll find principally that include/asm-$ARCH/ltt.h
> hold the timestamping mechanism for each architecture (does SH4 have a
> 64 or 32 bits timestamp counter ? (get_cycles()))

Just FYI, I don't know much about SH4, but KFT (which I used to maintain)
has a hard-coded readclock() routine (similar to get_cycles()).

Here's the routine from the KFT patches:

#ifdef CONFIG_CPU_SH4
/*
 * In advance, start Timer Unit4(TMU4)
 * ex.
 *  *TMU4_TCR = 0x0000;
 *  *TMU4_TCOR = 0;
 *  *TMU4_TCNT = 0;
 *  *TMU_TSTR2 = (*TMU_TSTR2|0x02);
 */
#define TMU4_TCNT       ((volatile unsigned long *)0xFE100018)

static inline unsigned long __noinstrument kft_readclock(void)
{
        return (-(*TMU4_TCNT))>>CLOCK_SHIFT;
}
#endif /* CONFIG_CPU_SH4 */

Have fun.
 -- Tim

=============================
Tim Bird
Architecture Group Chair, CE Linux Forum
Senior Staff Engineer, Sony Corporation of America
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