[PATCH AUTOSEL 4.9 085/251] clocksource/drivers/sun5i: Fail gracefully when clock rate is unavailable

Sasha Levin sashal at kernel.org
Thu Jan 16 09:33:54 PST 2020


From: Chen-Yu Tsai <wens at csie.org>

[ Upstream commit e7e7e0d7beafebd11b0c065cd5fbc1e5759c5aab ]

If the clock tree is not fully populated when the timer-sun5i init code
is called, attempts to get the clock rate for the timer would fail and
return 0.

Make the init code for both clock events and clocksource check the
returned clock rate and fail gracefully if the result is 0, instead of
causing a divide by 0 exception later on.

Fixes: 4a59058f0b09 ("clocksource/drivers/sun5i: Refactor the current code")
Signed-off-by: Chen-Yu Tsai <wens at csie.org>
Acked-by: Maxime Ripard <maxime.ripard at bootlin.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano at linaro.org>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 drivers/clocksource/timer-sun5i.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/clocksource/timer-sun5i.c b/drivers/clocksource/timer-sun5i.c
index 4f87f3e76d83..c3e96de525a2 100644
--- a/drivers/clocksource/timer-sun5i.c
+++ b/drivers/clocksource/timer-sun5i.c
@@ -201,6 +201,11 @@ static int __init sun5i_setup_clocksource(struct device_node *node,
 	}
 
 	rate = clk_get_rate(clk);
+	if (!rate) {
+		pr_err("Couldn't get parent clock rate\n");
+		ret = -EINVAL;
+		goto err_disable_clk;
+	}
 
 	cs->timer.base = base;
 	cs->timer.clk = clk;
@@ -274,6 +279,11 @@ static int __init sun5i_setup_clockevent(struct device_node *node, void __iomem
 	}
 
 	rate = clk_get_rate(clk);
+	if (!rate) {
+		pr_err("Couldn't get parent clock rate\n");
+		ret = -EINVAL;
+		goto err_disable_clk;
+	}
 
 	ce->timer.base = base;
 	ce->timer.ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
-- 
2.20.1




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