[PATCH] rtc/tpo: Handle disabled TPO in opal_get_tpo_time()

[Alexandre Belloni]

On 19/05/2017 at 15:35:09 +0530, Vaibhav Jain wrote:
> On PowerNV platform when Timed-Power-On(TPO) is disabled, read of
> stored TPO yields value with all date components set to '0' inside
> opal_get_tpo_time(). The function opal_to_tm() then converts it to an
> offset from year 1900 yielding alarm-time == "1900-00-01
> 00:00:00". This causes problems with __rtc_read_alarm() that
> expecting an offset from "1970-00-01 00:00:00" and returned alarm-time
> results in a -ve value for time64_t. Which ultimately results in this
> error reported in kernel logs with a seemingly garbage value:
> 
> "rtc rtc0: invalid alarm value: -2-1--1041528741
> 2005511117:71582844:32"
> 
> We fix this by explicitly handling the case of all alarm date-time
> components being '0' inside opal_get_tpo_time() and returning -ENOENT
> in such a case. This signals generic rtc that no alarm is set and it
> bails out from the alarm initialization flow without reporting the
> above error.
> 
> Signed-off-by: Vaibhav Jain <vaibhav at linux.vnet.ibm.com>
> Reported-by: Steve Best <sbest at redhat.com>
> ---
>  drivers/rtc/rtc-opal.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
Applied, thanks.

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com