Re: [PATCH v3 06/12] rtc: renesas-rtca3: Add driver for RTCA-3 available on Renesas RZ/G3S SoC

Alexandre Belloni
2024-09-03T17:36:24Z

On 03/09/2024 19:09:00+0300, claudiu beznea wrote:
> >
> > Also, w/o this change the RTC remains blocked under the following scenarios
> > if the interrupts are not disabled in remove:
>
> This intrigued me and did some further investigation. I found that
> something is wrong on the driver as described bellow.
>
> The failures described in the previous emails were due to the fact that the
> RTC counter clock was requested by the driver as devres managed resource.
> This is the clock that feeds the RTC counting logic.
>
> With the bellow diff applied on top of this series scenarios 1/ and 2/
> described in the previous email works just fine.
>
> For scenario 3/ the system is not powered up (as expected) but there are no
> more failures on the next boots.
>
> diff --git a/drivers/rtc/rtc-renesas-rtca3.c b/drivers/rtc/rtc-renesas-rtca3.c
> index f908d2a1017d..c9adcadc58c0 100644
> --- a/drivers/rtc/rtc-renesas-rtca3.c
> +++ b/drivers/rtc/rtc-renesas-rtca3.c
> @@ -747,10 +747,14 @@ static int rtca3_probe(struct platform_device *pdev)
> if (ret)
> return ret;
>
> - clk = devm_clk_get_enabled(dev, "counter");
> + clk = devm_clk_get(dev, "counter");
> if (IS_ERR(clk))
> return PTR_ERR(clk);
>
> + ret = clk_prepare_enable(clk);
> + if (ret)
> + return ret;
> +
> spin_lock_init(&priv->lock);
> atomic_set(&priv->alrm_sstep, RTCA3_ALRM_SSTEP_DONE);
> init_completion(&priv->set_alarm_completion);
> @@ -783,7 +787,7 @@ static void rtca3_remove(struct platform_device *pdev)
>
> guard(spinlock_irqsave)(&priv->lock);
>
> - rtca3_alarm_irq_set_helper(priv, RTCA3_RCR1_AIE | RTCA3_RCR1_PIE, 0);
> + //rtca3_alarm_irq_set_helper(priv, RTCA3_RCR1_AIE | RTCA3_RCR1_PIE, 0);
> }
>
> Question is: the RTC counter clock should stay on when the driver is
> unbinded, right?

Yes, the lifecycle of the RTC and its ressources is longer than the
system's as the whole point is to keep the time and date running while
the system is off.

>
> Thank you,
> Claudiu Beznea
>
> >
> > 1/ Configure wake alarm and unbind the RTC driver with the following commands:
> > # echo +10 > /sys/class/rtc/rtc0/wakealarm
> > # echo /sys/bus/platform/drivers/rtc-rtca3/1004ec00.rtc > unbind
> > # sleep 12
> > # echo /sys/bus/platform/drivers/rtc-rtca3/1004ec00.rtc > bind
> >
> > When rebinding the re-configuration of the RTC device times out:
> > [ 121.854190] rtc-rtca3 1004ec00.rtc: error -ETIMEDOUT: Failed to setup
> > the RTC!
> > [ 121.861511] rtc-rtca3 1004ec00.rtc: probe with driver rtc-rtca3 failed
> > with error -110
> > -sh: echo: write error: Connection timed out
> >
> > 2/ Configure wake alarm, unbind the RTC driver and switch to s2idle with
> > the following commands:
> > # echo s2idle > /sys/power/mem_sleep
> > # echo +10 > /sys/class/rtc/rtc0/wakealarm
> > # echo /sys/bus/platform/drivers/rtc-rtca/31004ec00.rtc > unbind
> > # echo mem > /sys/power/state
> > # #system is resumed by non RTC wakeup source (as the RTC alarm is not
> > working anymore in this case)
> > # echo /sys/bus/platform/drivers/rtc-rtca/1004ec00.rtc > bind
> >
> > The system is not waked up from RTC alarm (as expected) and the rebinding
> > fails again:
> >
> > [ 172.483688] rtc-rtca3 1004ec00.rtc: error -ETIMEDOUT: Failed to setup
> > the RTC!
> > [ 172.491003] rtc-rtca3 1004ec00.rtc: probe with driver rtc-rtca3 failed
> > with error -110
> > -sh: echo: write error: Connection timed out
> >
> > 3/ configure the RTC alarm, unbind and power off (with the following commands):
> > # echo +60 > /sys/class/rtc/rtc0/wakealarm
> > # echo /sys/bus/platform/drivers/rtc-rtca/1004ec00.rtc > unbind
> > # poweroff
> >
> > The system is not started after 60 seconds and at the next reboot the RTC
> > configuration on probe is failing the same:
> >
> > [ 0.292068] rtc-rtca3 1004ec00.rtc: error -ETIMEDOUT: Failed to setup
> > the RTC!
> > [ 0.292182] rtc-rtca3 1004ec00.rtc: probe with driver rtc-rtca3 failed
> > with error -110
> >
> > In all scenarios the RTC is recovered only if removing/re-applying the
> > power to the SoC area where it resides.
> >
> > These tests were done with the patches in this series and then I tried it
> > with the following diff on top of the patches in this series. The results
> > were the same:
> >
> > diff --git a/drivers/rtc/rtc-renesas-rtca3.c b/drivers/rtc/rtc-renesas-rtca3.c
> > index 822c055b6e4d..720fdac3adc6 100644
> > --- a/drivers/rtc/rtc-renesas-rtca3.c
> > +++ b/drivers/rtc/rtc-renesas-rtca3.c
> > @@ -586,7 +586,7 @@ static int rtca3_initial_setup(struct clk *clk, struct
> > rtca3_priv *priv)
> > usleep_range(sleep_us, sleep_us + 10);
> >
> > /* Disable alarm and carry interrupts. */
> > - mask = RTCA3_RCR1_AIE | RTCA3_RCR1_CIE;
> > + mask = RTCA3_RCR1_AIE | RTCA3_RCR1_CIE | RTCA3_RCR1_PIE;
> > ret = rtca3_alarm_irq_set_helper(priv, mask, 0);
> > if (ret)
> > return ret;
> > @@ -784,7 +784,7 @@ static void rtca3_remove(struct platform_device *pdev)
> > guard(spinlock_irqsave)(&priv->lock);
> >
> > /* Disable alarm, periodic interrupts. */
> > - rtca3_alarm_irq_set_helper(priv, RTCA3_RCR1_AIE | RTCA3_RCR1_PIE, 0);
> > + //rtca3_alarm_irq_set_helper(priv, RTCA3_RCR1_AIE | RTCA3_RCR1_PIE, 0);
> > }
> >
> > Thank you,
> > Claudiu Beznea
> >

--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering