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Date: Wed, 24 Jul 2019 12:31:59 +0300
From: Dmitry Osipenko <digetx@...il.com>
To: Sowjanya Komatineni <skomatineni@...dia.com>,
thierry.reding@...il.com, jonathanh@...dia.com, tglx@...utronix.de,
jason@...edaemon.net, marc.zyngier@....com,
linus.walleij@...aro.org, stefan@...er.ch, mark.rutland@....com
Cc: pdeschrijver@...dia.com, pgaikwad@...dia.com, sboyd@...nel.org,
linux-clk@...r.kernel.org, linux-gpio@...r.kernel.org,
jckuo@...dia.com, josephl@...dia.com, talho@...dia.com,
linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org,
mperttunen@...dia.com, spatra@...dia.com, robh+dt@...nel.org,
devicetree@...r.kernel.org
Subject: Re: [PATCH V6 16/21] soc/tegra: pmc: Add pmc wake support for
tegra210
24.07.2019 2:39, Sowjanya Komatineni пишет:
>
> On 7/23/19 7:27 AM, Dmitry Osipenko wrote:
>> 23.07.2019 6:43, Dmitry Osipenko пишет:
>>> 23.07.2019 6:31, Sowjanya Komatineni пишет:
>>>> On 7/22/19 8:25 PM, Dmitry Osipenko wrote:
>>>>> 23.07.2019 6:09, Sowjanya Komatineni пишет:
>>>>>> On 7/22/19 8:03 PM, Dmitry Osipenko wrote:
>>>>>>> 23.07.2019 4:52, Sowjanya Komatineni пишет:
>>>>>>>> On 7/22/19 6:41 PM, Dmitry Osipenko wrote:
>>>>>>>>> 23.07.2019 4:08, Dmitry Osipenko пишет:
>>>>>>>>>> 23.07.2019 3:58, Dmitry Osipenko пишет:
>>>>>>>>>>> 21.07.2019 22:40, Sowjanya Komatineni пишет:
>>>>>>>>>>>> This patch implements PMC wakeup sequence for Tegra210 and
>>>>>>>>>>>> defines
>>>>>>>>>>>> common used RTC alarm wake event.
>>>>>>>>>>>>
>>>>>>>>>>>> Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
>>>>>>>>>>>> ---
>>>>>>>>>>>> drivers/soc/tegra/pmc.c | 111
>>>>>>>>>>>> ++++++++++++++++++++++++++++++++++++++++++++++++
>>>>>>>>>>>> 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_MASK 0x0c
>>>>>>>>>>>> +#define PMC_WAKE_LEVEL 0x10
>>>>>>>>>>>> +#define PMC_WAKE_STATUS 0x14
>>>>>>>>>>>> +#define PMC_SW_WAKE_STATUS 0x18
>>>>>>>>>>>> #define DPD_SAMPLE 0x020
>>>>>>>>>>>> #define DPD_SAMPLE_ENABLE BIT(0)
>>>>>>>>>>>> @@ -87,6 +93,11 @@
>>>>>>>>>>>> #define PMC_SCRATCH41 0x140
>>>>>>>>>>>> +#define PMC_WAKE2_MASK 0x160
>>>>>>>>>>>> +#define PMC_WAKE2_LEVEL 0x164
>>>>>>>>>>>> +#define PMC_WAKE2_STATUS 0x168
>>>>>>>>>>>> +#define PMC_SW_WAKE2_STATUS 0x16c
>>>>>>>>>>>> +
>>>>>>>>>>>> #define PMC_SENSOR_CTRL 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 = {
>>>>>>>>>>>> .alloc = tegra_pmc_irq_alloc,
>>>>>>>>>>>> };
>>>>>>>>>>>> +static int tegra210_pmc_irq_set_wake(struct irq_data
>>>>>>>>>>>> *data,
>>>>>>>>>>>> unsigned int on)
>>>>>>>>>>>> +{
>>>>>>>>>>>> + struct tegra_pmc *pmc = irq_data_get_irq_chip_data(data);
>>>>>>>>>>>> + unsigned int offset, bit;
>>>>>>>>>>>> + u32 value;
>>>>>>>>>>>> +
>>>>>>>>>>>> + if (data->hwirq == ULONG_MAX)
>>>>>>>>>>>> + return 0;
>>>>>>>>>>>> +
>>>>>>>>>>>> + offset = data->hwirq / 32;
>>>>>>>>>>>> + bit = data->hwirq % 32;
>>>>>>>>>>>> +
>>>>>>>>>>>> + /*
>>>>>>>>>>>> + * Latch wakeups to SW_WAKE_STATUS register to capture
>>>>>>>>>>>> events
>>>>>>>>>>>> + * that would not make it into wakeup event register
>>>>>>>>>>>> during
>>>>>>>>>>>> LP0 exit.
>>>>>>>>>>>> + */
>>>>>>>>>>>> + value = tegra_pmc_readl(pmc, PMC_CNTRL);
>>>>>>>>>>>> + value |= PMC_CNTRL_LATCH_WAKEUPS;
>>>>>>>>>>>> + tegra_pmc_writel(pmc, value, PMC_CNTRL);
>>>>>>>>>>>> + 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?
>>>>>>>>>>>
>>>>>>>>>>>> + value &= ~PMC_CNTRL_LATCH_WAKEUPS;
>>>>>>>>>>>> + tegra_pmc_writel(pmc, value, PMC_CNTRL);
>>>>>>>>>>>> + udelay(120);
>>>>>>>>>>> 120 usecs to remove latching, really?
>>>>>>>>>>>
>>>>>>>>>>>> + tegra_pmc_writel(pmc, 0, PMC_SW_WAKE_STATUS);
>>>>>>>>>>>> + tegra_pmc_writel(pmc, 0, PMC_SW_WAKE2_STATUS);
>>>>>>>>>>>> +
>>>>>>>>>>>> + tegra_pmc_writel(pmc, 0, PMC_WAKE_STATUS);
>>>>>>>>>>>> + tegra_pmc_writel(pmc, 0, PMC_WAKE2_STATUS);
>>>>>>>>>>>> +
>>>>>>>>>>>> + /* enable PMC wake */
>>>>>>>>>>>> + if (data->hwirq >= 32)
>>>>>>>>>>>> + offset = PMC_WAKE2_MASK;
>>>>>>>>>>>> + else
>>>>>>>>>>>> + offset = PMC_WAKE_MASK;
>>>>>>>>>>>> +
>>>>>>>>>>>> + value = tegra_pmc_readl(pmc, offset);
>>>>>>>>>>>> +
>>>>>>>>>>>> + if (on)
>>>>>>>>>>>> + value |= 1 << bit;
>>>>>>>>>>>> + else
>>>>>>>>>>>> + value &= ~(1 << bit);
>>>>>>>>>>>> +
>>>>>>>>>>>> + 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.
>> Actually, it will be better to simply not implement the latching until
>> it will become really needed. In general you shouldn't add into the
>> patchset anything that is unused.
>
> OK, will remove latch_wake for now.
>
> Will send next version once I get all the review feedback ..
>
That's not a bad idea. Wait for one-two weeks and if it will happen that
nobody is replying, then just issue a new version.
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