clocksource/drivers/mips-gic-timer: Refine rating computation

It is a good clocksource which usually go as fast as CPU core
and have a low access latency, so raise the base of rating
from Good to desired when we know that it has a stable frequency.

Increase frequency addend dividend to 10000000 (10MHz) to
reasonably accommodate multi GHz level clock, also cap rating
within current level.
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Link: https://lore.kernel.org/r/20240612-mips-clks-v2-6-a57e6f49f3db@flygoat.comSigned-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/clocksource/mips-gic-timer.c

@@ -197,7 +197,11 @@ static int __init __gic_clocksource_init(void)
 	gic_clocksource.mask = CLOCKSOURCE_MASK(count_width);
 
 	/* Calculate a somewhat reasonable rating value. */
-	gic_clocksource.rating = 200 + gic_frequency / 10000000;
+	if (mips_cm_revision() >= CM_REV_CM3 || !IS_ENABLED(CONFIG_CPU_FREQ))
+		gic_clocksource.rating = 300; /* Good when frequecy is stable */
+	else
+		gic_clocksource.rating = 200;
+	gic_clocksource.rating += clamp(gic_frequency / 10000000, 0, 99);
 
 	ret = clocksource_register_hz(&gic_clocksource, gic_frequency);
 	if (ret < 0)