> -----Original Message----- > From: Nishanth Menon [mailto:nm@xxxxxx] > Sent: Sunday, February 20, 2011 10:42 AM > To: Vishwanath Sripathy > Cc: linux-omap; Tony Lindgren; Kevin Hilman > Subject: Re: [PATCH 03/19] omap3+: voltage: remove initial voltage > > Vishwanath Sripathy wrote, on 02/19/2011 06:54 PM: > [..] > >> omap2_set_init_voltage should setup the curr_volt based on which > OPP > >> the system is functioning at. Blindly setting a 1.2v setting in the > >> initial structure may not even match the default voltages stored in > >> the voltage table which are supported for the domain. > >> > >> For example, OMAP3430 core domain does not use 1.2v and ends up > >> generating a warning on the first transition. > >> > [..] > >> diff --git a/arch/arm/mach-omap2/voltage.c b/arch/arm/mach- > >> omap2/voltage.c > >> index 12be525..280ee12 100644 > >> --- a/arch/arm/mach-omap2/voltage.c > >> +++ b/arch/arm/mach-omap2/voltage.c > [..] > >> /* Generic voltage parameters */ > >> - vdd->curr_volt = 1200000; > > Where do you update this parameter upon initialization? Shouldn't you > read > > the VP register and find the actual current voltage and update this > param? > > The sequence is as follows: > a) omapx_vdd_data configure is called as part of sr init sequence. > And the curr_volt with this patch is not updated at this stage. > b) somewhere down in the boot sequence, pm.c's > omap2_set_init_voltage > starts up. This looks up the current clk frequency from clock layer of > the parent device for the domain, picks up the nominal voltages stored > in the opp layer, then does a omap_voltage_scale_vdd to that voltage. In > omap_voltage_scale_vdd, The current voltage is merely picked off the vp > (in _pre_volt_scale). the last step it does is to setup vdd->curr_volt. > This can then be used by dvfs layer etc to make appropriate decisions. > > So, No, I dont think I need to update it here, it should happen as part > of the pm init sequence. > > Could you explain what problem do you foresee by doing this? What if omap_voltage_scale_vdd fails when called from omap2_set_init_voltage? Or omap2_set_init_voltage returns error even before calling omap_voltage_scale_vdd because it could not find the matching voltage for the frequency set by bootloader? Your assumption that curr_volt is always set by omap2_set_init_voltage need not be true always. Vishwa > > -- > 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
