[PATCH v3 0/7] clocksource: Add NVIDIA Tegra186 timers support

[PATCH v3 0/7] clocksource: Add NVIDIA Tegra186 timers support

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

This set of patches adds the device tree bindings and a simplified
driver for the timers found on Tegra186 and later SoCs. The driver
itself currently only exposes a couple of clock sources and a
watchdog, which in turn relies on the counter provided by one of
the timers. The timers themselves are not used at the moment because
the SoC also has an architected timer and there's currently no use
for the additional timers provided by this hardware block.

I suggest that patches 1 & 2 go through the clocksource tree, while
I can carry the DTS changes in the Tegra tree for v5.8.

Changes in v3:
- request IRQ at the end of ->probe() to avoid potential race condition
- only enable/disable watchdog when it's active
- use _relaxed variants of register accessors
- drop unneeded tegra186_timer.irq field

Changes in v2:
- address review comments on the bindings
- make the driver buildable as a module
- support various clock sources

Thierry

Thierry Reding (7):
  dt-bindings: timer: Add bindings for NVIDIA Tegra186 timers
  clocksource: Add Tegra186 timers support
  arm64: tegra: Order nodes by unit-address on Tegra194
  arm64: tegra: Add native timer support on Tegra186
  arm64: tegra: Enable native timers on Jetson TX2
  arm64: tegra: Add native timer support on Tegra194
  arm64: tegra: Enable native timers on Jetson AGX Xavier

 .../bindings/timer/nvidia,tegra186-timer.yaml |  61 +++
 .../arm64/boot/dts/nvidia/tegra186-p3310.dtsi |   4 +
 arch/arm64/boot/dts/nvidia/tegra186.dtsi      |  16 +
 .../arm64/boot/dts/nvidia/tegra194-p2888.dtsi |   4 +
 arch/arm64/boot/dts/nvidia/tegra194.dtsi      |  81 +--
 drivers/clocksource/Kconfig                   |   8 +
 drivers/clocksource/Makefile                  |   1 +
 drivers/clocksource/timer-tegra186.c          | 508 ++++++++++++++++++
 8 files changed, 651 insertions(+), 32 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/timer/nvidia,tegra186-timer.yaml
 create mode 100644 drivers/clocksource/timer-tegra186.c

-- 
2.24.1

[PATCH v3 1/7] dt-bindings: timer: Add bindings for NVIDIA Tegra186 timers

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

The NVIDIA Tegra186 SoC contains an IP block that provides a register
interface for ten timers with a 29-bit counter that can generate one-
shot, periodic or watchdog interrupts.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
Changes in v2:
- add required properties section
- add additionalProperties: false
- do not show status in example

 .../bindings/timer/nvidia,tegra186-timer.yaml | 61 +++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/nvidia,tegra186-timer.yaml

diff --git a/Documentation/devicetree/bindings/timer/nvidia,tegra186-timer.yaml b/Documentation/devicetree/bindings/timer/nvidia,tegra186-timer.yaml
new file mode 100644
index 000000000000..d722cd267bf9
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/nvidia,tegra186-timer.yaml
@@ -0,0 +1,61 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/timer/nvidia,tegra186-timer.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NVIDIA Tegra186 timers
+
+maintainers:
+  - Thierry Reding <thierry.reding@gmail.com>
+  - Jonathan Hunter <jonathanh@nvidia.com>
+
+description: |
+  The Tegra186 timer provides ten 29-bit timer counters and one 32-bit TSC
+  (timestamp counter). The timers run at either a fixed 1 MHz clock rate
+  derived from the oscillator clock. Each timer can be programmed to raise
+  one-shot, periodic, or watchdog interrupts.
+
+properties:
+  compatible:
+    oneOf:
+      - description: NVIDIA Tegra186
+        items:
+          - const: nvidia,tegra186-timer
+
+      - description: NVIDIA Tegra194
+        items:
+          - const: nvidia,tegra194-timer
+          - const: nvidia,tegra186-timer
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 10
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    timer@3010000 {
+        compatible = "nvidia,tegra186-timer";
+        reg = <0x03010000 0x000e0000>;
+        interrupts = <GIC_SPI 0 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 2 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 4 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 5 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 6 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 9 IRQ_TYPE_LEVEL_HIGH>;
+    };
-- 
2.24.1

Re: [PATCH v3 1/7] dt-bindings: timer: Add bindings for NVIDIA Tegra186 timers

[Rob Herring]

On Fri,  3 Apr 2020 22:22:03 +0200, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
> 
> The NVIDIA Tegra186 SoC contains an IP block that provides a register
> interface for ten timers with a 29-bit counter that can generate one-
> shot, periodic or watchdog interrupts.
> 
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
> Changes in v2:
> - add required properties section
> - add additionalProperties: false
> - do not show status in example
> 
>  .../bindings/timer/nvidia,tegra186-timer.yaml | 61 +++++++++++++++++++
>  1 file changed, 61 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/timer/nvidia,tegra186-timer.yaml
> 

Reviewed-by: Rob Herring <robh@kernel.org>

[PATCH v3 2/7] clocksource: Add Tegra186 timers support

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

Currently this only supports a single watchdog, which uses a timer in
the background for countdown. Eventually the timers could be used for
various time-keeping tasks, but by default the architected timer will
already provide that functionality.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
Changes in v3:
- request IRQ at the end of ->probe() to avoid race condition
- only enable/disable watchdog when it's active
- use _relaxed variants of register accessors
- drop tegra186_timer.irq field

Changes in v2:
- add dependency on WATCHDOG && WATCHDOG_CORE
- expose TSC, OSC and USEC clocksources
- implement suspend/resume support
- make driver tristate

 drivers/clocksource/Kconfig          |   8 +
 drivers/clocksource/Makefile         |   1 +
 drivers/clocksource/timer-tegra186.c | 508 +++++++++++++++++++++++++++
 3 files changed, 517 insertions(+)
 create mode 100644 drivers/clocksource/timer-tegra186.c

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index f2142e6bbea3..385573c215d8 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -149,6 +149,14 @@ config TEGRA_TIMER
 	help
 	  Enables support for the Tegra driver.
 
+config TEGRA186_TIMER
+	tristate "NVIDIA Tegra186 timer driver"
+	depends on ARCH_TEGRA || COMPILE_TEST
+	depends on WATCHDOG && WATCHDOG_CORE
+	help
+	  Enables support for the timers and watchdogs found on NVIDIA
+	  Tegra186 and later SoCs.
+
 config VT8500_TIMER
 	bool "VT8500 timer driver" if COMPILE_TEST
 	depends on HAS_IOMEM
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 641ba5383ab5..ffa7950f4b7c 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_SUN4I_TIMER)	+= timer-sun4i.o
 obj-$(CONFIG_SUN5I_HSTIMER)	+= timer-sun5i.o
 obj-$(CONFIG_MESON6_TIMER)	+= timer-meson6.o
 obj-$(CONFIG_TEGRA_TIMER)	+= timer-tegra.o
+obj-$(CONFIG_TEGRA186_TIMER)	+= timer-tegra186.o
 obj-$(CONFIG_VT8500_TIMER)	+= timer-vt8500.o
 obj-$(CONFIG_NSPIRE_TIMER)	+= timer-zevio.o
 obj-$(CONFIG_BCM_KONA_TIMER)	+= bcm_kona_timer.o
diff --git a/drivers/clocksource/timer-tegra186.c b/drivers/clocksource/timer-tegra186.c
new file mode 100644
index 000000000000..4515517c87a5
--- /dev/null
+++ b/drivers/clocksource/timer-tegra186.c
@@ -0,0 +1,508 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2019-2020 NVIDIA Corporation. All rights reserved.
+ */
+
+#include <linux/clocksource.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/watchdog.h>
+
+/* shared registers */
+#define TKETSC0 0x000
+#define TKETSC1 0x004
+#define TKEUSEC 0x008
+#define TKEOSC  0x00c
+
+#define TKEIE(x) (0x100 + ((x) * 4))
+#define  TKEIE_WDT_MASK(x, y) ((y) << (16 + 4 * (x)))
+
+/* timer registers */
+#define TMRCR 0x000
+#define  TMRCR_ENABLE BIT(31)
+#define  TMRCR_PERIODIC BIT(30)
+#define  TMRCR_PTV(x) ((x) & 0x0fffffff)
+
+#define TMRSR 0x004
+#define  TMRSR_INTR_CLR BIT(30)
+
+#define TMRCSSR 0x008
+#define  TMRCSSR_SRC_USEC (0 << 0)
+
+/* watchdog registers */
+#define WDTCR 0x000
+#define  WDTCR_SYSTEM_POR_RESET_ENABLE BIT(16)
+#define  WDTCR_SYSTEM_DEBUG_RESET_ENABLE BIT(15)
+#define  WDTCR_REMOTE_INT_ENABLE BIT(14)
+#define  WDTCR_LOCAL_FIQ_ENABLE BIT(13)
+#define  WDTCR_LOCAL_INT_ENABLE BIT(12)
+#define  WDTCR_PERIOD_MASK (0xff << 4)
+#define  WDTCR_PERIOD(x) (((x) & 0xff) << 4)
+#define  WDTCR_TIMER_SOURCE_MASK 0xf
+#define  WDTCR_TIMER_SOURCE(x) ((x) & 0xf)
+
+#define WDTCMDR 0x008
+#define  WDTCMDR_DISABLE_COUNTER BIT(1)
+#define  WDTCMDR_START_COUNTER BIT(0)
+
+#define WDTUR 0x00c
+#define  WDTUR_UNLOCK_PATTERN 0x0000c45a
+
+struct tegra186_timer_soc {
+	unsigned int num_timers;
+	unsigned int num_wdts;
+};
+
+struct tegra186_tmr {
+	struct tegra186_timer *parent;
+	void __iomem *regs;
+	unsigned int index;
+	unsigned int hwirq;
+};
+
+struct tegra186_wdt {
+	struct watchdog_device base;
+
+	void __iomem *regs;
+	unsigned int index;
+	bool locked;
+
+	struct tegra186_tmr *tmr;
+};
+
+static inline struct tegra186_wdt *to_tegra186_wdt(struct watchdog_device *wdd)
+{
+	return container_of(wdd, struct tegra186_wdt, base);
+}
+
+struct tegra186_timer {
+	const struct tegra186_timer_soc *soc;
+	struct device *dev;
+	void __iomem *regs;
+
+	struct tegra186_wdt *wdt;
+	struct clocksource usec;
+	struct clocksource tsc;
+	struct clocksource osc;
+};
+
+static void tmr_writel(struct tegra186_tmr *tmr, u32 value, unsigned int offset)
+{
+	writel_relaxed(value, tmr->regs + offset);
+}
+
+static void wdt_writel(struct tegra186_wdt *wdt, u32 value, unsigned int offset)
+{
+	writel_relaxed(value, wdt->regs + offset);
+}
+
+static u32 wdt_readl(struct tegra186_wdt *wdt, unsigned int offset)
+{
+	return readl_relaxed(wdt->regs + offset);
+}
+
+static struct tegra186_tmr *tegra186_tmr_create(struct tegra186_timer *tegra,
+						unsigned int index)
+{
+	unsigned int offset = 0x10000 + index * 0x10000;
+	struct tegra186_tmr *tmr;
+
+	tmr = devm_kzalloc(tegra->dev, sizeof(*tmr), GFP_KERNEL);
+	if (!tmr)
+		return ERR_PTR(-ENOMEM);
+
+	tmr->parent = tegra;
+	tmr->regs = tegra->regs + offset;
+	tmr->index = index;
+	tmr->hwirq = 0;
+
+	return tmr;
+}
+
+static const struct watchdog_info tegra186_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
+	.identity = "NVIDIA Tegra186 WDT",
+};
+
+static void tegra186_wdt_disable(struct tegra186_wdt *wdt)
+{
+	/* unlock and disable the watchdog */
+	wdt_writel(wdt, WDTUR_UNLOCK_PATTERN, WDTUR);
+	wdt_writel(wdt, WDTCMDR_DISABLE_COUNTER, WDTCMDR);
+
+	/* disable timer */
+	tmr_writel(wdt->tmr, 0, TMRCR);
+}
+
+static void tegra186_wdt_enable(struct tegra186_wdt *wdt)
+{
+	struct tegra186_timer *tegra = wdt->tmr->parent;
+	u32 value;
+
+	/* unmask hardware IRQ, this may have been lost across powergate */
+	value = TKEIE_WDT_MASK(wdt->index, 1);
+	writel(value, tegra->regs + TKEIE(wdt->tmr->hwirq));
+
+	/* clear interrupt */
+	tmr_writel(wdt->tmr, TMRSR_INTR_CLR, TMRSR);
+
+	/* select microsecond source */
+	tmr_writel(wdt->tmr, TMRCSSR_SRC_USEC, TMRCSSR);
+
+	/* configure timer (system reset happens on the fifth expiration) */
+	value = TMRCR_PTV(wdt->base.timeout * USEC_PER_SEC / 5) |
+		TMRCR_PERIODIC | TMRCR_ENABLE;
+	tmr_writel(wdt->tmr, value, TMRCR);
+
+	if (!wdt->locked) {
+		value = wdt_readl(wdt, WDTCR);
+
+		/* select the proper timer source */
+		value &= ~WDTCR_TIMER_SOURCE_MASK;
+		value |= WDTCR_TIMER_SOURCE(wdt->tmr->index);
+
+		/* single timer period since that's already configured */
+		value &= ~WDTCR_PERIOD_MASK;
+		value |= WDTCR_PERIOD(1);
+
+		/* enable local interrupt for WDT petting */
+		value |= WDTCR_LOCAL_INT_ENABLE;
+
+		/* enable local FIQ and remote interrupt for debug dump */
+		if (0)
+			value |= WDTCR_REMOTE_INT_ENABLE |
+				 WDTCR_LOCAL_FIQ_ENABLE;
+
+		/* enable system debug reset (doesn't properly reboot) */
+		if (0)
+			value |= WDTCR_SYSTEM_DEBUG_RESET_ENABLE;
+
+		/* enable system POR reset */
+		value |= WDTCR_SYSTEM_POR_RESET_ENABLE;
+
+		wdt_writel(wdt, value, WDTCR);
+	}
+
+	wdt_writel(wdt, WDTCMDR_START_COUNTER, WDTCMDR);
+}
+
+static int tegra186_wdt_start(struct watchdog_device *wdd)
+{
+	struct tegra186_wdt *wdt = to_tegra186_wdt(wdd);
+
+	tegra186_wdt_enable(wdt);
+
+	return 0;
+}
+
+static int tegra186_wdt_stop(struct watchdog_device *wdd)
+{
+	struct tegra186_wdt *wdt = to_tegra186_wdt(wdd);
+
+	tegra186_wdt_disable(wdt);
+
+	return 0;
+}
+
+static int tegra186_wdt_ping(struct watchdog_device *wdd)
+{
+	struct tegra186_wdt *wdt = to_tegra186_wdt(wdd);
+
+	tegra186_wdt_disable(wdt);
+	tegra186_wdt_enable(wdt);
+
+	return 0;
+}
+
+static int tegra186_wdt_set_timeout(struct watchdog_device *wdd,
+				    unsigned int timeout)
+{
+	struct tegra186_wdt *wdt = to_tegra186_wdt(wdd);
+
+	if (watchdog_active(&wdt->base))
+		tegra186_wdt_disable(wdt);
+
+	wdt->base.timeout = timeout;
+
+	if (watchdog_active(&wdt->base))
+		tegra186_wdt_enable(wdt);
+
+	return 0;
+}
+
+static const struct watchdog_ops tegra186_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = tegra186_wdt_start,
+	.stop = tegra186_wdt_stop,
+	.ping = tegra186_wdt_ping,
+	.set_timeout = tegra186_wdt_set_timeout,
+};
+
+static struct tegra186_wdt *tegra186_wdt_create(struct tegra186_timer *tegra,
+						unsigned int index)
+{
+	unsigned int offset = 0x10000, source;
+	struct tegra186_wdt *wdt;
+	u32 value;
+	int err;
+
+	offset += tegra->soc->num_timers * 0x10000 + index * 0x10000;
+
+	wdt = devm_kzalloc(tegra->dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return ERR_PTR(-ENOMEM);
+
+	wdt->regs = tegra->regs + offset;
+	wdt->index = index;
+
+	/* read the watchdog configuration since it might be locked down */
+	value = wdt_readl(wdt, WDTCR);
+
+	if (value & WDTCR_LOCAL_INT_ENABLE)
+		wdt->locked = true;
+
+	source = value & WDTCR_TIMER_SOURCE_MASK;
+
+	wdt->tmr = tegra186_tmr_create(tegra, source);
+	if (IS_ERR(wdt->tmr))
+		return ERR_CAST(wdt->tmr);
+
+	wdt->base.info = &tegra186_wdt_info;
+	wdt->base.ops = &tegra186_wdt_ops;
+	wdt->base.min_timeout = 1;
+	wdt->base.max_timeout = 255;
+	wdt->base.parent = tegra->dev;
+
+	err = watchdog_init_timeout(&wdt->base, 5, tegra->dev);
+	if (err < 0) {
+		dev_err(tegra->dev, "failed to initialize timeout: %d\n", err);
+		return ERR_PTR(err);
+	}
+
+	err = devm_watchdog_register_device(tegra->dev, &wdt->base);
+	if (err < 0) {
+		dev_err(tegra->dev, "failed to register WDT: %d\n", err);
+		return ERR_PTR(err);
+	}
+
+	return wdt;
+}
+
+static u64 tegra186_timer_tsc_read(struct clocksource *cs)
+{
+	struct tegra186_timer *tegra = container_of(cs, struct tegra186_timer,
+						    tsc);
+	u32 hi, lo, ss;
+
+	hi = readl_relaxed(tegra->regs + TKETSC1);
+
+	/*
+	 * The 56-bit value of the TSC is spread across two registers that are
+	 * not synchronized. In order to read them atomically, ensure that the
+	 * high 24 bits match before and after reading the low 32 bits.
+	 */
+	do {
+		/* snapshot the high 24 bits */
+		ss = hi;
+
+		lo = readl_relaxed(tegra->regs + TKETSC0);
+		hi = readl_relaxed(tegra->regs + TKETSC1);
+	} while (hi != ss);
+
+	return (u64)hi << 32 | lo;
+}
+
+static int tegra186_timer_tsc_init(struct tegra186_timer *tegra)
+{
+	tegra->tsc.name = "tsc";
+	tegra->tsc.rating = 300;
+	tegra->tsc.read = tegra186_timer_tsc_read;
+	tegra->tsc.mask = CLOCKSOURCE_MASK(56);
+	tegra->tsc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+
+	return clocksource_register_hz(&tegra->tsc, 31250000);
+}
+
+static u64 tegra186_timer_osc_read(struct clocksource *cs)
+{
+	struct tegra186_timer *tegra = container_of(cs, struct tegra186_timer,
+						    osc);
+
+	return readl_relaxed(tegra->regs + TKEOSC);
+}
+
+static int tegra186_timer_osc_init(struct tegra186_timer *tegra)
+{
+	tegra->osc.name = "osc";
+	tegra->osc.rating = 300;
+	tegra->osc.read = tegra186_timer_osc_read;
+	tegra->osc.mask = CLOCKSOURCE_MASK(32);
+	tegra->osc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+
+	return clocksource_register_hz(&tegra->osc, 38400000);
+}
+
+static u64 tegra186_timer_usec_read(struct clocksource *cs)
+{
+	struct tegra186_timer *tegra = container_of(cs, struct tegra186_timer,
+						    usec);
+
+	return readl_relaxed(tegra->regs + TKEUSEC);
+}
+
+static int tegra186_timer_usec_init(struct tegra186_timer *tegra)
+{
+	tegra->usec.name = "usec";
+	tegra->usec.rating = 300;
+	tegra->usec.read = tegra186_timer_usec_read;
+	tegra->usec.mask = CLOCKSOURCE_MASK(32);
+	tegra->usec.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+
+	return clocksource_register_hz(&tegra->usec, USEC_PER_SEC);
+}
+
+static irqreturn_t tegra186_timer_irq(int irq, void *data)
+{
+	struct tegra186_timer *tegra = data;
+
+	if (watchdog_active(&tegra->wdt->base)) {
+		tegra186_wdt_disable(tegra->wdt);
+		tegra186_wdt_enable(tegra->wdt);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int tegra186_timer_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct tegra186_timer *tegra;
+	unsigned int irq;
+	int err;
+
+	tegra = devm_kzalloc(dev, sizeof(*tegra), GFP_KERNEL);
+	if (!tegra)
+		return -ENOMEM;
+
+	tegra->soc = of_device_get_match_data(dev);
+	dev_set_drvdata(dev, tegra);
+	tegra->dev = dev;
+
+	tegra->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(tegra->regs))
+		return PTR_ERR(tegra->regs);
+
+	err = platform_get_irq(pdev, 0);
+	if (err < 0)
+		return err;
+
+	irq = err;
+
+	/* create a watchdog using a preconfigured timer */
+	tegra->wdt = tegra186_wdt_create(tegra, 0);
+	if (IS_ERR(tegra->wdt)) {
+		err = PTR_ERR(tegra->wdt);
+		dev_err(dev, "failed to create WDT: %d\n", err);
+		return err;
+	}
+
+	err = tegra186_timer_tsc_init(tegra);
+	if (err < 0) {
+		dev_err(dev, "failed to register TSC counter: %d\n", err);
+		return err;
+	}
+
+	err = tegra186_timer_osc_init(tegra);
+	if (err < 0) {
+		dev_err(dev, "failed to register OSC counter: %d\n", err);
+		goto unregister_tsc;
+	}
+
+	err = tegra186_timer_usec_init(tegra);
+	if (err < 0) {
+		dev_err(dev, "failed to register USEC counter: %d\n", err);
+		goto unregister_osc;
+	}
+
+	err = devm_request_irq(dev, irq, tegra186_timer_irq, 0,
+			       "tegra186-timer", tegra);
+	if (err < 0) {
+		dev_err(dev, "failed to request IRQ#%u: %d\n", irq, err);
+		goto unregister_usec;
+	}
+
+	return 0;
+
+unregister_usec:
+	clocksource_unregister(&tegra->usec);
+unregister_osc:
+	clocksource_unregister(&tegra->osc);
+unregister_tsc:
+	clocksource_unregister(&tegra->tsc);
+	return err;
+}
+
+static int tegra186_timer_remove(struct platform_device *pdev)
+{
+	struct tegra186_timer *tegra = platform_get_drvdata(pdev);
+
+	clocksource_unregister(&tegra->usec);
+	clocksource_unregister(&tegra->osc);
+	clocksource_unregister(&tegra->tsc);
+
+	return 0;
+}
+
+static int __maybe_unused tegra186_timer_suspend(struct device *dev)
+{
+	struct tegra186_timer *tegra = dev_get_drvdata(dev);
+
+	if (watchdog_active(&tegra->wdt->base))
+		tegra186_wdt_disable(tegra->wdt);
+
+	return 0;
+}
+
+static int __maybe_unused tegra186_timer_resume(struct device *dev)
+{
+	struct tegra186_timer *tegra = dev_get_drvdata(dev);
+
+	if (watchdog_active(&tegra->wdt->base))
+		tegra186_wdt_enable(tegra->wdt);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(tegra186_timer_pm_ops, tegra186_timer_suspend,
+			 tegra186_timer_resume);
+
+static const struct tegra186_timer_soc tegra186_timer = {
+	.num_timers = 10,
+	.num_wdts = 3,
+};
+
+static const struct of_device_id tegra186_timer_of_match[] = {
+	{ .compatible = "nvidia,tegra186-timer", .data = &tegra186_timer },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, tegra186_timer_of_match);
+
+static struct platform_driver tegra186_wdt_driver = {
+	.driver = {
+		.name = "tegra186-timer",
+		.pm = &tegra186_timer_pm_ops,
+		.of_match_table = tegra186_timer_of_match,
+	},
+	.probe = tegra186_timer_probe,
+	.remove = tegra186_timer_remove,
+};
+module_platform_driver(tegra186_wdt_driver);
+
+MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
+MODULE_DESCRIPTION("NVIDIA Tegra186 timers driver");
+MODULE_LICENSE("GPL v2");
-- 
2.24.1

Re: [PATCH v3 2/7] clocksource: Add Tegra186 timers support

[Dmitry Osipenko]

03.04.2020 23:22, Thierry Reding пишет:
...
> +config TEGRA186_TIMER
> +	tristate "NVIDIA Tegra186 timer driver"
> +	depends on ARCH_TEGRA || COMPILE_TEST
> +	depends on WATCHDOG && WATCHDOG_CORE
> +	help
> +	  Enables support for the timers and watchdogs found on NVIDIA
> +	  Tegra186 and later SoCs.

Personally, I'd like to see this in drivers/watchdog/ because I've seen
cases where subsys maintainers are doing bulk-changes to drivers and
missing those that reside outside of the subsys directory.

But, that's not to me to decide, so I don't really mind.

...
> +static void tegra186_wdt_enable(struct tegra186_wdt *wdt)
> +{
> +	struct tegra186_timer *tegra = wdt->tmr->parent;
> +	u32 value;
> +
> +	/* unmask hardware IRQ, this may have been lost across powergate */
> +	value = TKEIE_WDT_MASK(wdt->index, 1);
> +	writel(value, tegra->regs + TKEIE(wdt->tmr->hwirq));

Perhaps this one also could be relaxed, for consistency. Sorry for
missing it in v2 :)

Re: [PATCH v3 2/7] clocksource: Add Tegra186 timers support

[Dmitry Osipenko]

03.04.2020 23:22, Thierry Reding пишет:
...
> +static irqreturn_t tegra186_timer_irq(int irq, void *data)
> +{
> +	struct tegra186_timer *tegra = data;
> +
> +	if (watchdog_active(&tegra->wdt->base)) {
> +		tegra186_wdt_disable(tegra->wdt);
> +		tegra186_wdt_enable(tegra->wdt);
> +	}

Shouldn't this return IRQ_NONE if watchdog is inactive?

> +	return IRQ_HANDLED;
> +}

Re: [PATCH v3 2/7] clocksource: Add Tegra186 timers support

[Dmitry Osipenko]

03.04.2020 23:51, Dmitry Osipenko пишет:
> 03.04.2020 23:22, Thierry Reding пишет:
> ...
>> +static irqreturn_t tegra186_timer_irq(int irq, void *data)
>> +{
>> +	struct tegra186_timer *tegra = data;
>> +
>> +	if (watchdog_active(&tegra->wdt->base)) {
>> +		tegra186_wdt_disable(tegra->wdt);
>> +		tegra186_wdt_enable(tegra->wdt);
>> +	}
> 
> Shouldn't this return IRQ_NONE if watchdog is inactive?
> 
>> +	return IRQ_HANDLED;
>> +}
> 

Could you please explain why this interrupt handler is needed at all?
Shouldn't the watchdog's core take care of the pinging?

Re: [PATCH v3 2/7] clocksource: Add Tegra186 timers support

[Dmitry Osipenko]

03.04.2020 23:22, Thierry Reding пишет:
...
> +static int tegra186_wdt_set_timeout(struct watchdog_device *wdd,
> +				    unsigned int timeout)
> +{
> +	struct tegra186_wdt *wdt = to_tegra186_wdt(wdd);
> +
> +	if (watchdog_active(&wdt->base))
> +		tegra186_wdt_disable(wdt);

Could this and other tegra186_wdt_enable/disable occurrences race with
the interrupt handler?

Shouldn't IRQ be disabled/enable in a such cases to avoid the races?

> +	wdt->base.timeout = timeout;
> +
> +	if (watchdog_active(&wdt->base))
> +		tegra186_wdt_enable(wdt);
> +
> +	return 0;
> +}

[PATCH v3 3/7] arm64: tegra: Order nodes by unit-address on Tegra194

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

The pin controller device tree node was accidentally added in the wrong
place. Move it to the correct location to keep nodes ordered by unit-
address.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 arch/arm64/boot/dts/nvidia/tegra194.dtsi | 64 ++++++++++++------------
 1 file changed, 32 insertions(+), 32 deletions(-)

diff --git a/arch/arm64/boot/dts/nvidia/tegra194.dtsi b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
index f4ede86e32b4..019f66f03a97 100644
--- a/arch/arm64/boot/dts/nvidia/tegra194.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
@@ -45,6 +45,38 @@ gpio: gpio@2200000 {
 			gpio-controller;
 		};
 
+		pinmux: pinmux@2430000 {
+			compatible = "nvidia,tegra194-pinmux";
+			reg = <0x2430000 0x17000
+			       0xc300000 0x4000>;
+
+			status = "okay";
+
+			pex_rst_c5_out_state: pex_rst_c5_out {
+				pex_rst {
+					nvidia,pins = "pex_l5_rst_n_pgg1";
+					nvidia,schmitt = <TEGRA_PIN_DISABLE>;
+					nvidia,lpdr = <TEGRA_PIN_ENABLE>;
+					nvidia,enable-input = <TEGRA_PIN_DISABLE>;
+					nvidia,io-high-voltage = <TEGRA_PIN_ENABLE>;
+					nvidia,tristate = <TEGRA_PIN_DISABLE>;
+					nvidia,pull = <TEGRA_PIN_PULL_NONE>;
+				};
+			};
+
+			clkreq_c5_bi_dir_state: clkreq_c5_bi_dir {
+				clkreq {
+					nvidia,pins = "pex_l5_clkreq_n_pgg0";
+					nvidia,schmitt = <TEGRA_PIN_DISABLE>;
+					nvidia,lpdr = <TEGRA_PIN_ENABLE>;
+					nvidia,enable-input = <TEGRA_PIN_ENABLE>;
+					nvidia,io-high-voltage = <TEGRA_PIN_ENABLE>;
+					nvidia,tristate = <TEGRA_PIN_DISABLE>;
+					nvidia,pull = <TEGRA_PIN_PULL_NONE>;
+				};
+			};
+		};
+
 		ethernet@2490000 {
 			compatible = "nvidia,tegra194-eqos",
 				     "nvidia,tegra186-eqos",
@@ -139,38 +171,6 @@ agic: interrupt-controller@2a40000 {
 			};
 		};
 
-		pinmux: pinmux@2430000 {
-			compatible = "nvidia,tegra194-pinmux";
-			reg = <0x2430000 0x17000
-			       0xc300000 0x4000>;
-
-			status = "okay";
-
-			pex_rst_c5_out_state: pex_rst_c5_out {
-				pex_rst {
-					nvidia,pins = "pex_l5_rst_n_pgg1";
-					nvidia,schmitt = <TEGRA_PIN_DISABLE>;
-					nvidia,lpdr = <TEGRA_PIN_ENABLE>;
-					nvidia,enable-input = <TEGRA_PIN_DISABLE>;
-					nvidia,io-high-voltage = <TEGRA_PIN_ENABLE>;
-					nvidia,tristate = <TEGRA_PIN_DISABLE>;
-					nvidia,pull = <TEGRA_PIN_PULL_NONE>;
-				};
-			};
-
-			clkreq_c5_bi_dir_state: clkreq_c5_bi_dir {
-				clkreq {
-					nvidia,pins = "pex_l5_clkreq_n_pgg0";
-					nvidia,schmitt = <TEGRA_PIN_DISABLE>;
-					nvidia,lpdr = <TEGRA_PIN_ENABLE>;
-					nvidia,enable-input = <TEGRA_PIN_ENABLE>;
-					nvidia,io-high-voltage = <TEGRA_PIN_ENABLE>;
-					nvidia,tristate = <TEGRA_PIN_DISABLE>;
-					nvidia,pull = <TEGRA_PIN_PULL_NONE>;
-				};
-			};
-		};
-
 		mc: memory-controller@2c00000 {
 			compatible = "nvidia,tegra194-mc";
 			reg = <0x02c00000 0x100000>,
-- 
2.24.1

[PATCH v3 4/7] arm64: tegra: Add native timer support on Tegra186

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

The native timers IP block found on NVIDIA Tegra SoCs implements a
watchdog timer that can be used to recover from system hangs. Add the
device tree node on Tegra186.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 arch/arm64/boot/dts/nvidia/tegra186.dtsi | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/arm64/boot/dts/nvidia/tegra186.dtsi b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
index 58100fb9cd8b..4dfa70e93693 100644
--- a/arch/arm64/boot/dts/nvidia/tegra186.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
@@ -167,6 +167,22 @@ emc: external-memory-controller@2c60000 {
 		};
 	};
 
+	timer@3010000 {
+		compatible = "nvidia,tegra186-timer";
+		reg = <0x0 0x03010000 0x0 0x000e0000>;
+		interrupts = <GIC_SPI 0 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 2 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 4 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 5 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 6 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 9 IRQ_TYPE_LEVEL_HIGH>;
+		status = "disabled";
+	};
+
 	uarta: serial@3100000 {
 		compatible = "nvidia,tegra186-uart", "nvidia,tegra20-uart";
 		reg = <0x0 0x03100000 0x0 0x40>;
-- 
2.24.1

[PATCH v3 5/7] arm64: tegra: Enable native timers on Jetson TX2

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

Enable the native timers on Jetson TX2 to allow using the watchdog
functionality to recover from system hangs, for example.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 arch/arm64/boot/dts/nvidia/tegra186-p3310.dtsi | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/boot/dts/nvidia/tegra186-p3310.dtsi b/arch/arm64/boot/dts/nvidia/tegra186-p3310.dtsi
index da96de04d003..9aa17744c4a0 100644
--- a/arch/arm64/boot/dts/nvidia/tegra186-p3310.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra186-p3310.dtsi
@@ -58,6 +58,10 @@ memory-controller@2c00000 {
 		status = "okay";
 	};
 
+	timer@3010000 {
+		status = "okay";
+	};
+
 	serial@3100000 {
 		status = "okay";
 	};
-- 
2.24.1

Re: [PATCH v3 5/7] arm64: tegra: Enable native timers on Jetson TX2

[Dmitry Osipenko]

03.04.2020 23:22, Thierry Reding пишет:
> From: Thierry Reding <treding@nvidia.com>
> 
> Enable the native timers on Jetson TX2 to allow using the watchdog
> functionality to recover from system hangs, for example.
> 
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
>  arch/arm64/boot/dts/nvidia/tegra186-p3310.dtsi | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/nvidia/tegra186-p3310.dtsi b/arch/arm64/boot/dts/nvidia/tegra186-p3310.dtsi
> index da96de04d003..9aa17744c4a0 100644
> --- a/arch/arm64/boot/dts/nvidia/tegra186-p3310.dtsi
> +++ b/arch/arm64/boot/dts/nvidia/tegra186-p3310.dtsi
> @@ -58,6 +58,10 @@ memory-controller@2c00000 {
>  		status = "okay";
>  	};
>  
> +	timer@3010000 {
> +		status = "okay";
> +	};

Why timer needs to be enabled per-board?

[PATCH v3 6/7] arm64: tegra: Add native timer support on Tegra194

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

The native timers IP block found on NVIDIA Tegra SoCs implements a
watchdog timer that can be used to recover from system hangs. Add the
device tree node on Tegra194.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 arch/arm64/boot/dts/nvidia/tegra194.dtsi | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/arch/arm64/boot/dts/nvidia/tegra194.dtsi b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
index 019f66f03a97..a0a5b44ff9bb 100644
--- a/arch/arm64/boot/dts/nvidia/tegra194.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
@@ -213,6 +213,23 @@ emc: external-memory-controller@2c60000 {
 			};
 		};
 
+		timer@3010000 {
+			compatible = "nvidia,tegra194-timer",
+				     "nvidia,tegra186-timer";
+			reg = <0x03010000 0x000e0000>;
+			interrupts = <GIC_SPI 0 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 2 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 4 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 5 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 6 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 9 IRQ_TYPE_LEVEL_HIGH>;
+			status = "disabled";
+		};
+
 		uarta: serial@3100000 {
 			compatible = "nvidia,tegra194-uart", "nvidia,tegra20-uart";
 			reg = <0x03100000 0x40>;
-- 
2.24.1

[PATCH v3 7/7] arm64: tegra: Enable native timers on Jetson AGX Xavier

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

Enable the native timers on Jetson AGX Xavier to allow using the
watchdog functionality to recover from system hangs, for example.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 arch/arm64/boot/dts/nvidia/tegra194-p2888.dtsi | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/boot/dts/nvidia/tegra194-p2888.dtsi b/arch/arm64/boot/dts/nvidia/tegra194-p2888.dtsi
index 623f7d7d216b..d68588f2709e 100644
--- a/arch/arm64/boot/dts/nvidia/tegra194-p2888.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra194-p2888.dtsi
@@ -52,6 +52,10 @@ memory-controller@2c00000 {
 			status = "okay";
 		};
 
+		timer@3010000 {
+			status = "okay";
+		};
+
 		serial@3110000 {
 			status = "okay";
 		};
-- 
2.24.1