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

From: Dmitry Osipenko
Date: Mon Jul 22 2019 - 21:52:45 EST

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23.07.2019 4:41, Dmitry Osipenko ÐÐÑÐÑ:
> 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>
>>>> ---
>>>> 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.

Okay, I re-read the TRM and apparently "latching" just means storing of
WAKE-event bit in the WAKE-status register if latching is enabled. Hence
the PMC_CNTRL_LATCHWAKE_EN should be enabled in tegra_pmc_suspend() and
unset in tegra_pmc_resume().

Also, apparently, on resume from suspend the interrupt should be
re-triggered in accordance to the WAKE-status, then the WAKE-status need
to be cleared.

>>>> + return 0;
>>>> +}
>>>> +
>>>> static int tegra186_pmc_irq_set_wake(struct irq_data *data, unsigned int on)
>>>> {
>>>> struct tegra_pmc *pmc = irq_data_get_irq_chip_data(data);
>>>> @@ -1954,6 +2014,49 @@ static int tegra186_pmc_irq_set_wake(struct irq_data *data, unsigned int on)
>>>> return 0;
>>>> }
>>>>
>>>> +static int tegra210_pmc_irq_set_type(struct irq_data *data, unsigned int type)
>>>> +{
>>>> + 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;
>>>> +
>>>> + if (data->hwirq >= 32)
>>>> + offset = PMC_WAKE2_LEVEL;
>>>> + else
>>>> + offset = PMC_WAKE_LEVEL;
>>>> +
>>>> + value = tegra_pmc_readl(pmc, offset);
>>>> +
>>>> + switch (type) {
>>>> + case IRQ_TYPE_EDGE_RISING:
>>>> + case IRQ_TYPE_LEVEL_HIGH:
>>>> + value |= 1 << bit;
>>>> + break;
>>>> +
>>>> + case IRQ_TYPE_EDGE_FALLING:
>>>> + case IRQ_TYPE_LEVEL_LOW:
>>>> + value &= ~(1 << bit);
>>>> + break;
>>>> +
>>>> + case IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING:
>>>> + value ^= 1 << bit;
>>>> + break;
>>>> +
>>>> + default:
>>>> + return -EINVAL;
>>>> + }
>>>> +
>>>> + tegra_pmc_writel(pmc, value, offset);
>>>
>>> Shouldn't the WAKE_LEVEL be latched as well?
>>>
>>>> + return 0;
>>>> +}
>>>> +
>>>> static int tegra186_pmc_irq_set_type(struct irq_data *data, unsigned int type)
>>>> {
>>>> struct tegra_pmc *pmc = irq_data_get_irq_chip_data(data);
>>>> @@ -2540,6 +2643,10 @@ static const struct pinctrl_pin_desc tegra210_pin_descs[] = {
>>>> TEGRA210_IO_PAD_TABLE(TEGRA_IO_PIN_DESC)
>>>> };
>>>>
>>>> +static const struct tegra_wake_event tegra210_wake_events[] = {
>>>> + TEGRA_WAKE_IRQ("rtc", 16, 2),
>>>> +};
>>>> +
>>>> static const struct tegra_pmc_soc tegra210_pmc_soc = {
>>>> .num_powergates = ARRAY_SIZE(tegra210_powergates),
>>>> .powergates = tegra210_powergates,
>>>> @@ -2557,10 +2664,14 @@ static const struct tegra_pmc_soc tegra210_pmc_soc = {
>>>> .regs = &tegra20_pmc_regs,
>>>> .init = tegra20_pmc_init,
>>>> .setup_irq_polarity = tegra20_pmc_setup_irq_polarity,
>>>> + .irq_set_wake = tegra210_pmc_irq_set_wake,
>>>> + .irq_set_type = tegra210_pmc_irq_set_type,
>>>> .reset_sources = tegra210_reset_sources,
>>>> .num_reset_sources = ARRAY_SIZE(tegra210_reset_sources),
>>>> .reset_levels = NULL,
>>>> .num_reset_levels = 0,
>>>> + .num_wake_events = ARRAY_SIZE(tegra210_wake_events),
>>>> + .wake_events = tegra210_wake_events,
>>>> };
>>>>
>>>> #define TEGRA186_IO_PAD_TABLE(_pad) \
>>>>
>>>
>>
>

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In reply to: Dmitry Osipenko: "Re: [PATCH V6 16/21] soc/tegra: pmc: Add pmc wake support for tegra210"
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