Messages in this thread | | | Subject | Re: [RFC PATCH 2/2] rtc: s3c: Add s3c_rtc_{enable/disable}_clk in s3c_rtc_setfreq() | From | Krzysztof Kozlowski <> | Date | Tue, 05 Jul 2016 10:16:25 +0200 |
| |
On 07/04/2016 01:03 PM, Alim Akhtar wrote: > As per code flow it is possible that s3c_rtc_setfreq() might get called > with rtc clock disabled and in set_freq we perform h/w registers read/write, > which might results in a kernel crash while probing rtc driver. > Below is one such case: > 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
The indentation suggests levels of calls (chain) not sequence. This should be: 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().
What I don't get is that you wrote "it is *possible* that s3c_rtc_setfreq() *might* get called". From my understanding this will happen always because src_rtc_gettime() always disables the clocks.
Why it does not happen always?
Best regards, Krzysztof
| |