[PATCH] clocksource: sun5i: fail gracefully when clock rate is unavailable

[PATCH] clocksource: sun5i: fail gracefully when clock rate is unavailable

[Chen-Yu Tsai]

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@csie.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 3b56ea3f52af..552c5254390c 100644
--- a/drivers/clocksource/timer-sun5i.c
+++ b/drivers/clocksource/timer-sun5i.c
@@ -202,6 +202,11 @@ 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;
@@ -275,6 +280,11 @@ 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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Re: [PATCH] clocksource: sun5i: fail gracefully when clock rate is unavailable

[Maxime Ripard]

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On Thu, Jan 10, 2019 at 02:22:07PM +0800, Chen-Yu Tsai wrote:
> 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@csie.org>

Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>

Thanks!
Maxime

-- 
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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Re: [PATCH] clocksource: sun5i: fail gracefully when clock rate is unavailable

[Daniel Lezcano]

On 10/01/2019 07:22, Chen-Yu Tsai wrote:
> 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@csie.org>
> ---

Applied thanks.
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Re: [PATCH] clocksource: sun5i: fail gracefully when clock rate is unavailable

[Chen-Yu Tsai]

On Thu, Jan 10, 2019 at 5:19 PM Daniel Lezcano
<daniel.lezcano@linaro.org> wrote:
>
> On 10/01/2019 07:22, Chen-Yu Tsai wrote:
> > 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@csie.org>
> > ---
>
> Applied thanks.

I'm not seeing this in linux-next, nor the patch

    arm64: arch_timer: Workaround for Allwinner A64 timer instability

Any idea where these ended up?


Thanks
ChenYu

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Re: [PATCH] clocksource: sun5i: fail gracefully when clock rate is unavailable

[Daniel Lezcano]

On 24/01/2019 09:56, Chen-Yu Tsai wrote:
> On Thu, Jan 10, 2019 at 5:19 PM Daniel Lezcano
> <daniel.lezcano@linaro.org> wrote:
>>
>> On 10/01/2019 07:22, Chen-Yu Tsai wrote:
>>> 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@csie.org>
>>> ---
>>
>> Applied thanks.
> 
> I'm not seeing this in linux-next, nor the patch
> 
>     arm64: arch_timer: Workaround for Allwinner A64 timer instability
> 
> Any idea where these ended up?

Yeah, I have a rough idea. They are now in linux-next via the
clockevents/next branch.




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