4.7-stable review patch. If anyone has any objections, please let me know.
------------------ From: Alim Akhtar <[email protected]> commit 70c96dfac0e231424e17743bd52f6cd2ff1f2439 upstream. As per code flow s3c_rtc_setfreq() will get called with rtc clock disabled and in set_freq we perform h/w registers read/write, which results in a kernel crash on exynos7 platform while probing rtc driver. Below is code flow: s3c_rtc_probe() clk_prepare_enable(info->rtc_clk) // rtc clock enabled s3c_rtc_gettime() // will enable clk if not done, and disable it upon exit s3c_rtc_setfreq() //then this will be called with clk disabled This patch take cares of such issue by adding s3c_rtc_{enable/disable}_clk in s3c_rtc_setfreq(). Fixes: 24e1455493da ("drivers/rtc/rtc-s3c.c: delete duplicate clock control") Signed-off-by: Alim Akhtar <[email protected]> Reviewed-by: Krzysztof Kozlowski <[email protected]> Reviewed-by: Pankaj Dubey <[email protected]> Tested-by: Pankaj Dubey <[email protected]> Signed-off-by: Alexandre Belloni <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/rtc/rtc-s3c.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/rtc/rtc-s3c.c +++ b/drivers/rtc/rtc-s3c.c @@ -149,12 +149,14 @@ static int s3c_rtc_setfreq(struct s3c_rt if (!is_power_of_2(freq)) return -EINVAL; + s3c_rtc_enable_clk(info); spin_lock_irq(&info->pie_lock); if (info->data->set_freq) info->data->set_freq(info, freq); spin_unlock_irq(&info->pie_lock); + s3c_rtc_disable_clk(info); return 0; }
