Re: [PATCH v12 2/5] soc: qcom: Add Sleep stats driver

[Shawn Guo <shawn.guo@linaro.org>]

On Thu, Oct 21, 2021 at 03:11:26PM +0530, Maulik Shah wrote:
> Hi Shawn,
> 
> On 10/21/2021 7:27 AM, Shawn Guo wrote:
> > On Tue, Oct 19, 2021 at 06:16:57PM +0530, Maulik Shah wrote:
> > > Hi Shawn,
> > > 
> > > On 10/19/2021 3:17 PM, Shawn Guo wrote:
> > > > On Mon, Oct 18, 2021 at 07:45:30PM +0530, Maulik Shah wrote:
> > > > > > > +static void qcom_create_soc_sleep_stat_files(struct dentry *root, void __iomem *reg,
> > > > > > > +					     struct stats_data *d,
> > > > > > > +					     const struct stats_config *config)
> > > > > > > +{
> > > > > > > +	char stat_type[sizeof(u32) + 1] = {0};
> > > > > > > +	size_t stats_offset = config->stats_offset;
> > > > > > > +	u32 offset = 0, type;
> > > > > > > +	int i, j;
> > > > > > > +
> > > > > > > +	/*
> > > > > > > +	 * On RPM targets, stats offset location is dynamic and changes from target
> > > > > > > +	 * to target and sometimes from build to build for same target.
> > > > > > > +	 *
> > > > > > > +	 * In such cases the dynamic address is present at 0x14 offset from base
> > > > > > > +	 * address in devicetree. The last 16bits indicates the stats_offset.
> > > > > > > +	 */
> > > > > > > +	if (config->dynamic_offset) {
> > > > > > > +		stats_offset = readl(reg + RPM_DYNAMIC_ADDR);
> > > > > > > +		stats_offset &= RPM_DYNAMIC_ADDR_MASK;
> > > > > > > +	}
> > > > > > > +
> > > > > > > +	for (i = 0; i < config->num_records; i++) {
> > > > > > > +		d[i].base = reg + offset + stats_offset;
> > > > > > > +
> > > > > > > +		/*
> > > > > > > +		 * Read the low power mode name and create debugfs file for it.
> > > > > > > +		 * The names read could be of below,
> > > > > > > +		 * (may change depending on low power mode supported).
> > > > > > > +		 * For rpmh-sleep-stats: "aosd", "cxsd" and "ddr".
> > > > > > > +		 * For rpm-sleep-stats: "vmin" and "vlow".
> > > > > > 
> > > > > > It reports 'vmin' and 'xosd' on MSM8939, 'vmin' and 'vlow' on SDM660.
> > > > > > I know that 'vmin' is VDD Minimization mode, and 'xosd' is XO Shutdown
> > > > > > mode.  But I'm not sure about 'vlow' mode.  Could you share some
> > > > > > information regarding what this low power mode is, and how it differs
> > > > > > from 'vmin' and 'xosd'?
> > > > > 
> > > > > vlow and xosd are same.
> > > > > vmin is xosd plus voltage minimization of chip, memory rails.
> > > > 
> > > > Thanks much for the info, Maulik!
> > > > 
> > > > I'm running your driver on qcm2290 and trying to reach vlow mode.
> > > > 
> > > > # cat /sys/kernel/debug/qcom_sleep_stats/vlow
> > > > Count: 0
> > > > Last Entered At: 0
> > > > Last Exited At: 0
> > > > Accumulated Duration: 0
> > > > Client Votes: 0x81
> > > > # echo mem > /sys/power/state
> > > > [  551.446603] PM: suspend entry (s2idle)
> > > > [  551.450948] Filesystems sync: 0.000 seconds
> > > > [  551.462828] Freezing user space processes ... (elapsed 0.002 seconds) done.
> > > > [  551.472276] OOM killer disabled.
> > > > [  551.475556] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
> > > > [  551.484461] printk: Suspending console(s) (use no_console_suspend to debug)
> > > > [  551.561280] OOM killer enabled.
> > > > [  551.564461] Restarting tasks ... done.
> > > > [  551.569652] PM: suspend exit
> > > > # cat /sys/kernel/debug/qcom_sleep_stats/vlow
> > > > Count: 0
> > > > Last Entered At: 0
> > > > Last Exited At: 0
> > > > Accumulated Duration: 0
> > > > Client Votes: 0x818081
> > > > 
> > > > The count doesn't increases along with suspend/resume cycle at the
> > > > moment.  But as you can see, 'Client Votes' field changes.  If possible,
> > > > could you shed some light on what this means?
> > > 
> > > The count will increase only when all the subsystems (APSS/Modem,etc) are in
> > > power down mode and finally RPM decides to turn off xo clock.
> > > 
> > > > 
> > > > As the comparison, I'm also running the downstream 'rpm_master_stats'
> > > > driver in the same kernel, and the 'xo_count' field of APSS does
> > > > increase along with suspend/resume cycle.  May I ask some advices what
> > > > I'm possibly missing and thus getting different result between 'vlow'
> > > > and 'rpm_master_stats' report?
> > > 
> > > The vlow is a SoC level state whereas the rpm master stats indicate
> > > individual subsystem state. Since you are running suspend-resume the APSS is
> > > going to sleep so you see xo_count incremented for it but for MPSS i see it
> > > does not increase (modem is not entering to low power mode). similarly for
> > > ADSP/CDSP it does not increment. if all of these subsystems goes to power
> > > down and then there is sufficient sleep time for the SoC then you may see
> > > vlow/vmin incrementing.
> > > 
> > > Hope this clarifies.
> > 
> > Thanks Maulik!  It's very helpful.  I have a couple of further
> > questions, if you do not mind.
> > 
> > 1. We can understand most of vlow/vmin output.  But could you help
> >     decode 'Client Votes'?  It looks like the bits are shifting along
> >     with suspend/resume cycle.
> > 
> 
> Client votes are history of client votes on xo. Each byte represents xo
> clock votes from subsystems.
> 
> 
> > 2. In the rpm_master_stats output below, I know masters (processors)
> >     APSS, MPSS, ADSP and CDSP, but not really sure what TZ is.  If it's
> >     TrustZone, shouldn't it covered by APSS?
> 
> Yes it indicates for Trustzone but should be covered by APSS.

Thanks for confirming, Maulik!

Interestingly, while I'm seeing xo_count of APSS and TZ increase together
along with suspend on downstream kernel, with my upstream based kernel,
only APSS xo_count increases and TZ always stay at 0.  I guess that's
why I cannot reach vlow mode.  Do you have any suggestion why this
happens?  I must have something missing from my kernel.  Thanks!

Shawn

> > > > # cat /sys/kernel/debug/rpm_master_stats
> > > > APSS
> > > >           shutdown_req:0x37EA3CC74
> > > >           wakeup_ind:0x0
> > > >           bringup_req:0x37F041958
> > > >           bringup_ack:0x37F042D54
> > > >           xo_last_entered_at:0x286FF36AC
> > > >           xo_last_exited_at:0x28AF94178
> > > >           xo_accumulated_duration:0x3EDD55B
> > > >           last_sleep_transition_duration:0x122f
> > > >           last_wake_transition_duration:0x11f8
> > > >           xo_count:0x1
> > > >           wakeup_reason:0x0
> > > >           numshutdowns:0x641
> > > >           active_cores:0x1
> > > >                   core0
> > > > MPSS
> > > >           shutdown_req:0x0
> > > >           wakeup_ind:0x0
> > > >           bringup_req:0x0
> > > >           bringup_ack:0x0
> > > >           xo_last_entered_at:0x0
> > > >           xo_last_exited_at:0x0
> > > >           xo_accumulated_duration:0x0
> > > >           last_sleep_transition_duration:0x0
> > > >           last_wake_transition_duration:0x0
> > > >           xo_count:0x0
> > > >           wakeup_reason:0x0
> > > >           numshutdowns:0x0
> > > >           active_cores:0x1
> > > >                   core0
> > > > ADSP
> > > >           shutdown_req:0x0
> > > >           wakeup_ind:0x0
> > > >           bringup_req:0x0
> > > >           bringup_ack:0x0
> > > >           xo_last_entered_at:0x0
> > > >           xo_last_exited_at:0x0
> > > >           xo_accumulated_duration:0x0
> > > >           last_sleep_transition_duration:0x0
> > > >           last_wake_transition_duration:0x0
> > > >           xo_count:0x0
> > > >           wakeup_reason:0x0
> > > >           numshutdowns:0x0
> > > >           active_cores:0x1
> > > >                   core0
> > > > CDSP
> > > >           shutdown_req:0x0
> > > >           wakeup_ind:0x0
> > > >           bringup_req:0x0
> > > >           bringup_ack:0x0
> > > >           xo_last_entered_at:0x0
> > > >           xo_last_exited_at:0x0
> > > >           xo_accumulated_duration:0x0
> > > >           last_sleep_transition_duration:0x0
> > > >           last_wake_transition_duration:0x0
> > > >           xo_count:0x0
> > > >           wakeup_reason:0x0
> > > >           numshutdowns:0x0
> > > >           active_cores:0x0
> > > > TZ
> > > >           shutdown_req:0x0
> > > >           wakeup_ind:0x0
> > > >           bringup_req:0x0
> > > >           bringup_ack:0x0
> > > >           xo_last_entered_at:0x0
> > > >           xo_last_exited_at:0x0
> > > >           xo_accumulated_duration:0x0
> > > >           last_sleep_transition_duration:0x0
> > > >           last_wake_transition_duration:0x0
> > > >           xo_count:0x0
> > > >           wakeup_reason:0x0
> > > >           numshutdowns:0x0
> > > >           active_cores:0x0
> 
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