[PATCH v1 2/4] clocksource: arm_architected_timer: support clock-frequency

[Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>]

Some platforms, like the Samsung Galaxy S8, leave CNTFRQ_EL0 unset in
the previous stage bootloader. Therefore reading it causes a hang and
the boot proccess is halted.

Since on such retail devices there is no way to set it without replacing
the entire boot chain, allow setting a value from clock-frequency
whenever it's passed.

Signed-off-by: Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>
---
 drivers/clocksource/arm_architected_timer.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/arm_architected_timer.c b/drivers/clocksource/arm_architected_timer.c
index 9a1f2d2b..daced94c 100644
--- a/drivers/clocksource/arm_architected_timer.c
+++ b/drivers/clocksource/arm_architected_timer.c
@@ -24,7 +24,16 @@ static struct clocksource cs = {
 
 static int arm_arch_timer_probe(struct device *dev)
 {
-	cs.mult = clocksource_hz2mult(get_cntfrq(), cs.shift);
+	u32 cntfrq;
+	int ret;
+
+	/* Some platforms don't set CNTFRQ_EL0 before barebox */
+	ret = of_property_read_u32(dev->of_node, "clock-frequency", &cntfrq);
+
+	if (ret)
+		cntfrq = get_cntfrq();
+
+	cs.mult = clocksource_hz2mult(cntfrq, cs.shift);
 
 	return init_clock(&cs);
 }
-- 
2.43.0