[PATCH v2 6/7] clocksource: mips-gic-timer: Refine rating computation

From: Jiaxun Yang
Date: Wed Jun 12 2024 - 04:56:21 EST


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@xxxxxxxxxxx>
---
v2: Fix number of zeros for 10 MHz
---
drivers/clocksource/mips-gic-timer.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c
index b3ae38f36720..7a03d94c028a 100644
--- a/drivers/clocksource/mips-gic-timer.c
+++ b/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)

--
2.43.0