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

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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@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.
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.
LATCHWAKE_EN - When set, enables latching and stops latching on
transition from 1 to 0
There is recommendation of min 120uSec for this transition to stop
latching. Will double-check why 120uSec
Yes, please check.

+	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?
WAKE_LEVELs dont need any latch as they are the levels SW sets for wake
trigger and they are not status
Okay.

[snip]




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