[PATCH] clocksource/drivers/imx-tpm: exclude sched clock for ARM64

From: Peng Fan (OSS)
Date: Wed Jan 05 2022 - 07:44:01 EST


From: Peng Fan <peng.fan@xxxxxxx>

For ARM64 platform such as i.MX8ULP which has ARMv8 generic timer as sched
clock, which is much faster compared with tpm sched clock. Reading the
tpm count register in i.MX8ULP requires about 290ns, this is slow and
introduce scheduler latency. So exclude tpm sched clock for ARM64
platform.

Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
---
drivers/clocksource/timer-imx-tpm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clocksource/timer-imx-tpm.c b/drivers/clocksource/timer-imx-tpm.c
index 2cdc077a39f5..2bd530b9adc4 100644
--- a/drivers/clocksource/timer-imx-tpm.c
+++ b/drivers/clocksource/timer-imx-tpm.c
@@ -150,10 +150,10 @@ static int __init tpm_clocksource_init(void)
tpm_delay_timer.read_current_timer = &tpm_read_current_timer;
tpm_delay_timer.freq = timer_of_rate(&to_tpm) >> 3;
register_current_timer_delay(&tpm_delay_timer);
-#endif

sched_clock_register(tpm_read_sched_clock, counter_width,
timer_of_rate(&to_tpm) >> 3);
+#endif

return clocksource_mmio_init(timer_base + TPM_CNT,
"imx-tpm",
--
2.25.1