>-----Original Message----- >From: ext Kevin Hilman [mailto:khilman@xxxxxxxxxxxxxxxxxxx] >Sent: 21 October, 2009 17:15 >To: Kristo Tero (Nokia-D/Tampere) >Cc: linux-omap@xxxxxxxxxxxxxxx >Subject: Re: [PATCH 16/17] OMAP3: PM: Write voltage and clock >setup times dynamically in idle loop > ><Tero.Kristo@xxxxxxxxx> writes: > >> >> >>>-----Original Message----- >>>From: ext Kevin Hilman [mailto:khilman@xxxxxxxxxxxxxxxxxxx] >>>Sent: 20 October, 2009 20:48 >>>To: Kristo Tero (Nokia-D/Tampere) >>>Cc: linux-omap@xxxxxxxxxxxxxxx >>>Subject: Re: [PATCH 16/17] OMAP3: PM: Write voltage and clock >>>setup times dynamically in idle loop >>> >>>Tero Kristo <tero.kristo@xxxxxxxxx> writes: >>> >>>> From: Tero Kristo <tero.kristo@xxxxxxxxx> >>>> >>>> It is suggested by TI (SWPA152 February 2009) to write clksetup, >>>> voltsetup_time1, voltsetup_time2, voltsetup2 dynamically in >>>idle loop. >>> >>>Can you summarize the reasons why? >> >> Basically this optimizes the clksetup / voltsetup times >according to the sleep mode. Currently the settings are too >high in both retention and off-mode, because the hardware >appears to use for example VOLTSETUP2 even if we are not in >off-mode, adding extra delay to wakeup. Also, CLKSETUP is too >high for retention mode because oscillator is not actually >shut-off here. >> >> However, now that I think about it, it might be better to >change this in a way that it is user configurable whether we >want to change the settings or not, maybe add new items in to >the prm_setup struct for alternate settings for ret / off and >only use these if available. Some boards might actually switch >oscillator off in retention mode which would require higher setup time. >> >>> >>>> Signed-off-by: Jouni Hogander <jouni.hogander@xxxxxxxxx> >>>> --- >>>> arch/arm/mach-omap2/pm34xx.c | 36 >>>+++++++++++++++++++++++++----------- >>>> 1 files changed, 25 insertions(+), 11 deletions(-) >>>> >>>> diff --git a/arch/arm/mach-omap2/pm34xx.c >>>b/arch/arm/mach-omap2/pm34xx.c >>>> index f492142..ae83121 100644 >>>> --- a/arch/arm/mach-omap2/pm34xx.c >>>> +++ b/arch/arm/mach-omap2/pm34xx.c >>>> @@ -575,6 +575,30 @@ void omap_sram_idle(void) >>>> if (regset_save_on_suspend) >>>> pm_dbg_regset_save(1); >>>> >>>> + /* Write voltage setup times which are changed dynamically */ >>> >>>AFAICT, we only set these values at init time and they are never >>>changed. Are there some forthcoming patches that change these >>>dynamically? >> >> Following bit of the code actually changes them dynamically, you can >> see that e.g. CLKSETUP time is either prm_setup.clksetup or 0x1 >> depending on the sleep mode. > >Doh, I see now. > >> But as previously said, I think these should probably be added as >> new items to the prm_setup struct. > >Yes, I would rather see the prm_setup struct extended so these can be >passed in by board code. I'll change the patch accordingly. >>> >>>Kevin >>> >>>> + if (core_next_state == PWRDM_POWER_OFF) { >>>> + prm_write_mod_reg(0, OMAP3430_GR_MOD, >>>> + OMAP3_PRM_VOLTSETUP1_OFFSET); >>>> + prm_write_mod_reg(prm_setup.voltsetup2, OMAP3430_GR_MOD, >>>> + OMAP3_PRM_VOLTSETUP2_OFFSET); >>>> + prm_write_mod_reg(prm_setup.clksetup, OMAP3430_GR_MOD, >>>> + OMAP3_PRM_CLKSETUP_OFFSET); >>>> + } else { >>>> + prm_write_mod_reg((prm_setup.voltsetup_time2 << >>>> + OMAP3430_SETUP_TIME2_SHIFT) | >>>> + (prm_setup.voltsetup_time1 << >>>> + OMAP3430_SETUP_TIME1_SHIFT), >>>> + OMAP3430_GR_MOD, >>>OMAP3_PRM_VOLTSETUP1_OFFSET); >>>> + prm_write_mod_reg(0, OMAP3430_GR_MOD, >>>> + OMAP3_PRM_VOLTSETUP2_OFFSET); >>>> + /* >>>> + * Use static 1 as only HF_CLKOUT is turned off. >>>> + * Value taken from application note SWPA152 >>>> + */ >>>> + prm_write_mod_reg(0x1, OMAP3430_GR_MOD, >>>> + OMAP3_PRM_CLKSETUP_OFFSET); >>>> + } >>>> + >>>> /* >>>> * omap3_arm_context is the location where ARM registers >>>> * get saved. The restore path then reads from this >>>> @@ -1379,19 +1403,9 @@ static void __init configure_vc(void) >>>> OMAP3430_GR_MOD, >>>> OMAP3_PRM_VC_I2C_CFG_OFFSET); >>>> >>>> - /* Write setup times */ >>>> - prm_write_mod_reg(prm_setup.clksetup, OMAP3430_GR_MOD, >>>> - OMAP3_PRM_CLKSETUP_OFFSET); >>>> - prm_write_mod_reg((prm_setup.voltsetup_time2 << >>>> - OMAP3430_SETUP_TIME2_SHIFT) | >>>> - (prm_setup.voltsetup_time1 << >>>> - OMAP3430_SETUP_TIME1_SHIFT), >>>> - OMAP3430_GR_MOD, OMAP3_PRM_VOLTSETUP1_OFFSET); >>>> - >>>> + /* Write static setup times */ >>>> prm_write_mod_reg(prm_setup.voltoffset, OMAP3430_GR_MOD, >>>> OMAP3_PRM_VOLTOFFSET_OFFSET); >>>> - prm_write_mod_reg(prm_setup.voltsetup2, OMAP3430_GR_MOD, >>>> - OMAP3_PRM_VOLTSETUP2_OFFSET); >>>> >>>> pm_dbg_regset_init(1); >>>> pm_dbg_regset_init(2); >>>> -- >>>> 1.5.4.3 >>>> >>>> -- >>>> 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 >>> >-- 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
