Subject: [PATCH 0/3] ARM: OMAP2+: hwmod: RTC: Add lock and unlock hooks

From: [email-masked] (Tero Kristo)
Date: Thu, 16 Jul 2015 10:09:23 +0300

On 07/16/2015 03:15 AM, Paul Walmsley wrote:
> On Tue, 14 Jul 2015, Tero Kristo wrote:
>
>> On 07/14/2015 01:09 PM, Lokesh Vutla wrote:
>>> Hi,
>>> On Wednesday 10 June 2015 02:56 PM, Lokesh Vutla wrote:
>>>> Some IP blocks like RTC, needs an additional unlocking mechanism for
>>>> writing to its registers. This patch adds optional lock and unlock
>>>> function pointers to the IP block's hwmod data which gets executed
>>>> before and after writing into IP sysconfig register.
>>>> And also hook lock and unlock functions to AMx3xx, DRA7 RTC hwmod data,
>>>> so that sysconfig registers are updated properly.
>>> ping on this series.
>>>
>>> Thanks and regards,
>>> Lokesh
>>
>
> [...]
>
>> It is also racy, as there is no locking in place to avoid concurrent access to
>> the lock/unlock registers across hwmod+driver.
>
> I don't see the race.  Where is it?

See drivers/rtc/rtc-omap.c, am3352_rtc_unlock and am3352_rtc_lock.

That code is accessing the exact same registers.

-Tero