clocksource/drivers/sun4i: Clear interrupts after stopping timer in probe function

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[ Upstream commit b53e7d000d ]

The bootloader (U-boot) sometimes uses this timer for various delays.
It uses it as a ongoing counter, and does comparisons on the current
counter value. The timer counter is never stopped.

In some cases when the user interacts with the bootloader, or lets
it idle for some time before loading Linux, the timer may expire,
and an interrupt will be pending. This results in an unexpected
interrupt when the timer interrupt is enabled by the kernel, at
which point the event_handler isn't set yet. This results in a NULL
pointer dereference exception, panic, and no way to reboot.

Clear any pending interrupts after we stop the timer in the probe
function to avoid this.

Cc: stable@vger.kernel.org
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

...

This commit is contained in:

Chen-Yu Tsai 2016-08-25 14:26:59 +08:00 • committed by Sasha Levin

parent 82d1894c12

commit c8ca488fa4

1 changed files with 8 additions and 1 deletions

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drivers/clocksource/sun4i_timer.c

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