> -----Original Message----- > From: Cousson, Benoit > Sent: Wednesday, October 14, 2009 11:06 AM > To: Pandita, Vikram; linux-omap@xxxxxxxxxxxxxxx > > >From: Pandita, Vikram > > > > > >Proposals for OPP table handling for OMAP34xx/35xx/36xx/44xx > > > >Thanks to all the community members for taking time for this discussion. > >This will aid upsteaming of 35xx/36xx/44xx in coming future. > > > >Attendees: Kevin Hilman, Paul, Nishant M, Santosh, Madhu, Benoit, > Rajendra, > >Benoit, Vikram > > > >Problem Statement: > > OMAP34xx has certain opp requirements (3420/3430/3440) > > OMAP35xx reuses the opp's from 34xx > > OMAP36xx has a totally new set of opps > > OMAP44xx has a totally new set of opps > > > >Solution: > > Align on a common approach to take for the Opp table definitions. > > > >Define Separate Tables for each family as follows: > >Step 1: Go with this approach: > > 3420(65nm) : new arrays [defer for now] > > 3430/35xx(65nm) : new arrays ** > > 3440(65nm) : new arrays [defer for now] > > 3630(45nm) : new arrays > > Omap4(45nm) : new arrays > > > > * new arrays = (mpu, dsp, l3) > > ** Check this valid flag. Kevin can take this base on comments > > http://marc.info/?l=linux-omap&m=125512448216071&w=2 > > between 3430/35xx, opp's can be managed with a flag and same > >table re-used > > 35xx has requirement for 720Mhz opp > > > >Step 2: > >Kevin suggestion: > >Define accessor APIs get the OPPs > >Check Users of accessor API > > DVFS > > constraints > > sysfs debug > > Define accessor api's eg: > > index = get_opp(VDD1_OPP1); > > num = get_max_opp(VDD1); > > set_opp(index); > > I think we should as well change the naming and use the less confusing > naming we are using on OMAP3630/4430. > OPPs are now named using the performance delta from the nominal frequency. > OPP25, OPP50, OPP80, OPP100, OPP120... NAK for two reasons: a) h/w changes language of OPP definitions every other silicons -> OPP100 is not more informative than OPP1 or OPPX for that matter - with proper comments, even something like /* OPP25 - 25% of nominal performance */ #define VDD1_OPP_REAAAALLLY_SLOW_OPP 1 Makes sense. b) if you look at discussion - we really DON'T want to use OPP definitions anymore - we would like folks to use frequency for precisely that reason - it is frequency that matters in the system. c) the field for OPP idx is probably redundant once we have proper APIs in place. > > Regards, > Benoit > > >Step 3: > > Paul suggestion: > > VSEL values in opp table should be in terms of voltage > > Non TWL IC's need this > > > >Step4: > > Paul suggestion: > > VDD1 VDD2 dependencies for different chips > > Inter-connect load predictor is absent on omap3 and hence VDD1-vdd2 > >dependency > > OMAP4 > > interconnect loading can be measured from registers > > Multi-cores dependency > > > >Step 5: > > Paul suggestion: > > Board files adding OPPs, Modifying OPPs > > Eg: Pendora passing its own opp > > Regards, Nishanth Menon -- 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
