Re: [PATCH V6 16/21] soc/tegra: pmc: Add pmc wake support for tegra210

[Dmitry Osipenko]

23.07.2019 6:31, Sowjanya Komatineni ÐÐÑÐÑ:
> 
> On 7/22/19 8:25 PM, Dmitry Osipenko wrote:
>> 23.07.2019 6:09, Sowjanya Komatineni ÐÐÑÐÑ:
>>> On 7/22/19 8:03 PM, Dmitry Osipenko wrote:
>>>> 23.07.2019 4:52, Sowjanya Komatineni ÐÐÑÐÑ:
>>>>> On 7/22/19 6:41 PM, Dmitry Osipenko wrote:
>>>>>> 23.07.2019 4:08, Dmitry Osipenko ÐÐÑÐÑ:
>>>>>>> 23.07.2019 3:58, Dmitry Osipenko ÐÐÑÐÑ:
>>>>>>>> 21.07.2019 22:40, Sowjanya Komatineni ÐÐÑÐÑ:
>>>>>>>>> This patch implements PMC wakeup sequence for Tegra210 and defines
>>>>>>>>> common used RTC alarm wake event.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
>>>>>>>>> ---
>>>>>>>>> ÂÂ drivers/soc/tegra/pmc.c | 111
>>>>>>>>> ++++++++++++++++++++++++++++++++++++++++++++++++
>>>>>>>>> ÂÂ 1 file changed, 111 insertions(+)
>>>>>>>>>
>>>>>>>>> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
>>>>>>>>> index 91c84d0e66ae..c556f38874e1 100644
>>>>>>>>> --- a/drivers/soc/tegra/pmc.c
>>>>>>>>> +++ b/drivers/soc/tegra/pmc.c
>>>>>>>>> @@ -57,6 +57,12 @@
>>>>>>>>>  #define PMC_CNTRL_SYSCLK_OE BIT(11) /* system clock
>>>>>>>>> enable */
>>>>>>>>>  #define PMC_CNTRL_SYSCLK_POLARITY BIT(10) /* sys clk
>>>>>>>>> polarity */
>>>>>>>>>  #define PMC_CNTRL_MAIN_RST BIT(4)
>>>>>>>>> +#define PMC_CNTRL_LATCH_WAKEUPS BIT(5)
>>>>>>> Please follow the TRM's bits naming.
>>>>>>>
>>>>>>> PMC_CNTRL_LATCHWAKE_EN
>>>>>>>
>>>>>>>>> +#define PMC_WAKE_MASKÂÂÂÂÂÂÂÂÂÂÂ 0x0c
>>>>>>>>> +#define PMC_WAKE_LEVELÂÂÂÂÂÂÂÂÂÂÂ 0x10
>>>>>>>>> +#define PMC_WAKE_STATUSÂÂÂÂÂÂÂÂÂÂÂ 0x14
>>>>>>>>> +#define PMC_SW_WAKE_STATUSÂÂÂÂÂÂÂ 0x18
>>>>>>>>> ÂÂ Â #define DPD_SAMPLEÂÂÂÂÂÂÂÂÂÂÂ 0x020
>>>>>>>>>  #define DPD_SAMPLE_ENABLE BIT(0)
>>>>>>>>> @@ -87,6 +93,11 @@
>>>>>>>>> ÂÂ Â #define PMC_SCRATCH41ÂÂÂÂÂÂÂÂÂÂÂ 0x140
>>>>>>>>> ÂÂ +#define PMC_WAKE2_MASKÂÂÂÂÂÂÂÂÂÂÂ 0x160
>>>>>>>>> +#define PMC_WAKE2_LEVELÂÂÂÂÂÂÂÂÂÂÂ 0x164
>>>>>>>>> +#define PMC_WAKE2_STATUSÂÂÂÂÂÂÂ 0x168
>>>>>>>>> +#define PMC_SW_WAKE2_STATUSÂÂÂÂÂÂÂ 0x16c
>>>>>>>>> +
>>>>>>>>> ÂÂ #define PMC_SENSOR_CTRLÂÂÂÂÂÂÂÂÂÂÂ 0x1b0
>>>>>>>>>  #define PMC_SENSOR_CTRL_SCRATCH_WRITE BIT(2)
>>>>>>>>>  #define PMC_SENSOR_CTRL_ENABLE_RST BIT(1)
>>>>>>>>> @@ -1922,6 +1933,55 @@ static const struct irq_domain_ops
>>>>>>>>> tegra_pmc_irq_domain_ops = {
>>>>>>>>> ÂÂÂÂÂÂ .alloc = tegra_pmc_irq_alloc,
>>>>>>>>> ÂÂ };
>>>>>>>>> ÂÂ +static int tegra210_pmc_irq_set_wake(struct irq_data *data,
>>>>>>>>> unsigned int on)
>>>>>>>>> +{
>>>>>>>>> +ÂÂÂ struct tegra_pmc *pmc = irq_data_get_irq_chip_data(data);
>>>>>>>>> +ÂÂÂ unsigned int offset, bit;
>>>>>>>>> +ÂÂÂ u32 value;
>>>>>>>>> +
>>>>>>>>> +ÂÂÂ if (data->hwirq == ULONG_MAX)
>>>>>>>>> +ÂÂÂÂÂÂÂ return 0;
>>>>>>>>> +
>>>>>>>>> +ÂÂÂ offset = data->hwirq / 32;
>>>>>>>>> +ÂÂÂ bit = data->hwirq % 32;
>>>>>>>>> +
>>>>>>>>> +ÂÂÂ /*
>>>>>>>>> +ÂÂÂÂ * Latch wakeups to SW_WAKE_STATUS register to capture events
>>>>>>>>> +ÂÂÂÂ * that would not make it into wakeup event register during
>>>>>>>>> LP0 exit.
>>>>>>>>> +ÂÂÂÂ */
>>>>>>>>> +ÂÂÂ value = tegra_pmc_readl(pmc, PMC_CNTRL);
>>>>>>>>> +ÂÂÂ value |= PMC_CNTRL_LATCH_WAKEUPS;
>>>>>>>>> +ÂÂÂ tegra_pmc_writel(pmc, value, PMC_CNTRL);
>>>>>>>>> +ÂÂÂ udelay(120);
>>>>>>>> Why it takes so much time to latch the values? Shouldn't some
>>>>>>>> status-bit
>>>>>>>> be polled for the completion of latching?
>>>>>>>>
>>>>>>>> Is this register-write really getting buffered in the PMC?
>>>>>>>>
>>>>>>>>> +ÂÂÂ value &= ~PMC_CNTRL_LATCH_WAKEUPS;
>>>>>>>>> +ÂÂÂ tegra_pmc_writel(pmc, value, PMC_CNTRL);
>>>>>>>>> +ÂÂÂ udelay(120);
>>>>>>>> 120 usecs to remove latching, really?
>>>>>>>>
>>>>>>>>> +ÂÂÂ tegra_pmc_writel(pmc, 0, PMC_SW_WAKE_STATUS);
>>>>>>>>> +ÂÂÂ tegra_pmc_writel(pmc, 0, PMC_SW_WAKE2_STATUS);
>>>>>>>>> +
>>>>>>>>> +ÂÂÂ tegra_pmc_writel(pmc, 0, PMC_WAKE_STATUS);
>>>>>>>>> +ÂÂÂ tegra_pmc_writel(pmc, 0, PMC_WAKE2_STATUS);
>>>>>>>>> +
>>>>>>>>> +ÂÂÂ /* enable PMC wake */
>>>>>>>>> +ÂÂÂ if (data->hwirq >= 32)
>>>>>>>>> +ÂÂÂÂÂÂÂ offset = PMC_WAKE2_MASK;
>>>>>>>>> +ÂÂÂ else
>>>>>>>>> +ÂÂÂÂÂÂÂ offset = PMC_WAKE_MASK;
>>>>>>>>> +
>>>>>>>>> +ÂÂÂ value = tegra_pmc_readl(pmc, offset);
>>>>>>>>> +
>>>>>>>>> +ÂÂÂ if (on)
>>>>>>>>> +ÂÂÂÂÂÂÂ value |= 1 << bit;
>>>>>>>>> +ÂÂÂ else
>>>>>>>>> +ÂÂÂÂÂÂÂ value &= ~(1 << bit);
>>>>>>>>> +
>>>>>>>>> +ÂÂÂ tegra_pmc_writel(pmc, value, offset);
>>>>>>>> Why the latching is done *before* writing into the WAKE registers?
>>>>>>>> What
>>>>>>>> it is latching then?
>>>>>>> I'm looking at the TRM doc and it says that latching should be done
>>>>>>> *after* writing to the WAKE_MASK / LEVEL registers.
>>>>>>>
>>>>>>> Secondly it says that it's enough to do:
>>>>>>>
>>>>>>> value = tegra_pmc_readl(pmc, PMC_CNTRL);
>>>>>>> value |= PMC_CNTRL_LATCH_WAKEUPS;
>>>>>>> tegra_pmc_writel(pmc, value, PMC_CNTRL);
>>>>>>>
>>>>>>> in order to latch. There is no need for the delay and to remove the
>>>>>>> "LATCHWAKE_EN" bit, it should be a oneshot action.
>>>>>> Although, no. TRM says "stops latching on transition from 1
>>>>>> to 0 (sequence - set to 1,set to 0)", so it's not a oneshot action.
>>>>>>
>>>>>> Have you tested this code at all? I'm wondering how it happens to
>>>>>> work
>>>>>> without a proper latching.
>>>>> Yes, ofcourse its tested and this sequence to do transition is
>>>>> recommendation from Tegra designer.
>>>>> Will check if TRM doesn't have update properly or will re-confirm
>>>>> internally on delay time...
>>>>>
>>>>> On any of the wake event PMC wakeup happens and WAKE_STATUS register
>>>>> will have bits set for all events that triggered wake.
>>>>> After wakeup PMC doesn't update SW_WAKE_STATUS register as per PMC
>>>>> design.
>>>>> SW latch register added in design helps to provide a way to capture
>>>>> those events that happen right during wakeup time and didnt make it to
>>>>> SW_WAKE_STATUS register.
>>>>> So before next suspend entry, latching all prior wake events into SW
>>>>> WAKE_STATUS and then clearing them.
>>>> I'm now wondering whether the latching cold be turned ON permanently
>>>> during of the PMC's probe, for simplicity.
>>> latching should be done on suspend-resume cycle as wake events gets
>>> generates on every suspend-resume cycle.
>> You're saying that PMC "doesn't update SW_WAKE_STATUS" after wake-up,
>> then I don't quite understand what's the point of disabling the latching
>> at all.
> When latch wake enable is set, events are latched and during 1 to 0
> transition latching is disabled.
> 
> This is to avoid sw_wake_status and wake_status showing diff events.

Okay.

> Currently driver is not relying on SW_WAKE_STATUS but its good to latch
> and clear so even at some point for some reason when SW_WAKE_STATUS is
> used, this wlil not cause mismatch with wake_status.

Then the latching need to be enabled on suspend and disabled early on
resume to get a proper WAKE status.

[snip]