> -----Original Message----- > From: "Högander" Jouni [mailto:jouni.hogander@xxxxxxxxx] > Sent: Thursday, July 03, 2008 11:28 AM > To: ext Rajendra Nayak > Cc: linux-omap@xxxxxxxxxxxxxxx > Subject: Re: [PATCH 00/11] OMAP3 CPUidle patches > > "ext Rajendra Nayak" <rnayak@xxxxxx> writes: > > > Hi, > > > > The following patches define and enable all of the below > mentioned C states for OMAP3. > > These are tested with a minimal kernel config on > OMAP3430sdp as most drivers today don't have context > save/restore in place and > > some even lack aggresive clock handling. > > These apply on top of the workaround patch set submitted by Jouni. > > ([PATCH 0/6] 34XX: PM: Workarounds to get omap3 to retention 4th.) > > > > The following is neccessay even with a minimal config to > achieve OFF. > > $ echo 1 > /sys/power/sleep_while_idle > > $ echo 1 > /sys/power/clocks_off_while_idle > > > > The following C states are defined > > C0 - System executing code > > C1 - MPU WFI + Core active > > C2 - MPU CSWR + Core active > > C3 - MPU OFF + Core active > > C4 - MPU CSWR + Core CSWR > > C5 - MPU OFF + Core CSWR > > C6 - MPU OFF + Core OFF > > > > regards, > > Rajendra > > One more general comment on these patches as I looked at the code > after applying them. > > Most of the code in omap3_enter_idle in cpuidle34xx.c could be shared > between suspend/pm_idle/cpuidle. I would do these changes to share > this code between these three things: > > 1. read mpu_pd pwrst, neon_pd pwrst, core_pd pwrst values in > omap_sram_idle in pm34xx.c > > 2. Move all the logic from omap3_enter_idle to omap_sram_idle. Use > values read in previous step to decide wether ctx savings/restores > are needed, what should be written to neon_pd next_pwrst, wether > omap2_gpio_prepare_for/resume_after_retention is needed, wether to > disable/enable serial and gpio clocks. > > Basically what is left into omap3_enter_idle is writing next pwrsts > and cpuidle related stuff, something like this: > > static int omap3_enter_idle(struct cpuidle_device *dev, > struct cpuidle_state *state) > { > struct omap3_processor_cx *cx = cpuidle_get_statedata(state); > struct timespec ts_preidle, ts_postidle, ts_idle; > struct powerdomain *mpu_pd, *core_pd; > > current_cx_state = *cx; > > if (cx->type == OMAP3_STATE_C0) { > /* Do nothing for C0, not even a wfi */ > return 0; > } > > local_irq_disable(); > local_fiq_disable(); > > /* Used to keep track of the total time in idle */ > getnstimeofday(&ts_preidle); > > if (cx->type > OMAP3_STATE_C1) > sched_clock_idle_sleep_event(); /* about to > enter deep idle */ > > mpu_pd = pwrdm_lookup("mpu_pwrdm"); > core_pd = pwrdm_lookup("core_pwrdm"); > > pwrdm_set_next_pwrst(mpu_pd, cx->mpu_state); > pwrdm_set_next_pwrst(core_pd, cx->core_state); > > if (omap_irq_pending()) > goto return_sleep_time; > > /* Execute ARM wfi */ > omap_sram_idle(); > > return_sleep_time: > getnstimeofday(&ts_postidle); > ts_idle = timespec_sub(ts_postidle, ts_preidle); > > if (cx->type > OMAP3_STATE_C1) > sched_clock_idle_wakeup_event(timespec_to_ns(&ts_idle)); > > local_irq_enable(); > local_fiq_disable(); > > return (u32)timespec_to_ns(&ts_idle)/1000; > } > > If this is not done, we need to copy paste code from omap3_enter_idle > into suspend code anyway if we want to use offmode in it. It would be > more nice to have one funcion with this logic shared between > suspend/pm_idle/cpuidle rather than two or even three copies of it. Yes, all this looks good to me. > > -- > Jouni Högander > > -- 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
