Hi Lokesh On Tue, 25 Nov 2014, Lokesh Vutla wrote: > Hi Paul, > On Thursday 20 November 2014 10:26 PM, Paul Walmsley wrote: > > On Thu, 20 Nov 2014, Lokesh Vutla wrote: > > > >> On Monday 17 November 2014 10:13 AM, Lokesh Vutla wrote: > >>> RTC IP have kicker feature which prevents spurious writes to its registers. > >>> In order to write into any of the RTC registers, KICK values has te be > >>> written to KICK registers. Currently hwmod is updating the IDLEMODE in rtc > >>> sysconfig register without writing into any kick register which is a noop. > >>> When autoidle is allowed for rtc, interruts are not received until IDLEMODE > >>> is set to SIDLE_SMART_WKUP. > >>> Adding a reset function to unlock RTC registers so that IDLEMODE is > >>> updated. > >> Ping..!! > >> Is this patch acceptable? > > > > Lokesh > > > > 1. This looks like a fix. Is this intended to go in as a v3.18-rc patch, > > or against v3.19? If so it would be very helpful for the maintainers if > > you were to state that somewhere. > Yes. This is a fix, intended to go in 3.18-rc. Sorry should have > mentioned it. A few questions. Do you know when this problem started (in terms of kernel versions)? Also: the patch description states that this is only a problem when autoidle is allowed for RTC. What enables autoidle for RTC - the RTCSS driver? Or does hwmod wind up doing this after the RTCSS driver unlocks it? > > 2. Your patch unlocks the RTC registers, but never relocks it. This seems > > to defeat the point of the spurious write protection. Shouldn't your > > patch only unlock the RTC immediately before the hwmod code touches the > > RTC registers, and then relock it immediately afterwards, per SPRUHZ6 > > section 23.4.3.3? If so then the .reset function pointer is the wrong > > place for this; I would suggest adding some .lock and .unlock function > > pointers that are to be called before and after any register write to the > > IP block. > Yeah I agree with you. > Currently rtc driver unlocks these kick registers in probe and leaves it unlocks for > further use. > But if hwmod does unlock and lock for every sysconfig write driver should also > implement unlock and lock for every rtc register write, which adds an extra overhead. > I am not sure if some one writes into rtc registers other than hwmod and driver. > IMO we can leave it unlocked as the driver does. I would think that the best approach would be to set up .lock and .unlock function pointers, then add a temporary hwmod flag that, if set, would prevent the .lock function from ever being called. Then once the driver is fixed, that flag can be dropped. > > 3. Your macros don't mention DRA7xx specifically. Does this sequence > > apply to some other TI chips, or just DRA7xx? Please document this in a > > comment above the macros, and possibly change the name of the macros to > > refer to DRA7XX. > This sequence applies to AM43xx and AM33xx also. So made it generic. > Ill document it. OK but it would need more than just documentation, right? Wouldn't the hwmod data also need to be modified for AM33xx/AM43xx to add the .reset function pointer? Any reason why folks wouldn't have seen this problem on AM33xx/AM43xx? - Paul -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
