[PATCH v3 0/6] Add watchdog timer support for Tegra186/194/234 SoCs

[PATCH v3 0/6] Add watchdog timer support for Tegra186/194/234 SoCs

[Kartik]

The native timers IP block found on Tegra SoCs implements a watchdog
timer that can be used to recover from system hangs. This series of
patches adds support for watchdog timers available on Tegra186,
Tegra194 and Tegra234 SOC's.

To keep the history intact, I added Tegra234 driver change as separate.
The original patchset is an old one authored by Thierry.

Kartik (4):
  dt-bindings: timer: Add Tegra186 & Tegra234 Timer
  clocksource/drivers/timer-tegra186: Add support for Tegra234 SoC
  arm64: tegra: Enable native timers on Tegra186
  arm64: tegra: Enable native timers on Tegra234

Thierry Reding (2):
  clocksource: Add Tegra186 timers support
  arm64: tegra: Enable native timers on Tegra194

 .../bindings/timer/nvidia,tegra186-timer.yaml | 109 ++++
 arch/arm64/boot/dts/nvidia/tegra186.dtsi      |   2 +-
 arch/arm64/boot/dts/nvidia/tegra194.dtsi      |  16 +
 arch/arm64/boot/dts/nvidia/tegra234.dtsi      |  22 +
 drivers/clocksource/Kconfig                   |   8 +
 drivers/clocksource/Makefile                  |   1 +
 drivers/clocksource/timer-tegra186.c          | 514 ++++++++++++++++++
 7 files changed, 671 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/timer/nvidia,tegra186-timer.yaml
 create mode 100644 drivers/clocksource/timer-tegra186.c

-- 
2.17.1

[PATCH v3 1/6] dt-bindings: timer: Add Tegra186 & Tegra234 Timer

[Kartik]

The Tegra186 timer provides ten 29-bit timer counters and one 32-bit
timestamp counter. The Tegra234 timer provides sixteen 29-bit timer
counters and one 32-bit timestamp counter. Each NV timer selects its
timing reference signal from the 1 MHz reference generated by USEC,
TSC or either clk_m or OSC. Each TMR can be programmed to generate
one-shot, periodic, or watchdog interrupts.

Signed-off-by: Kartik <kkartik@nvidia.com>
---
 .../bindings/timer/nvidia,tegra186-timer.yaml | 109 ++++++++++++++++++
 1 file changed, 109 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..db8b5595540f
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/nvidia,tegra186-timer.yaml
@@ -0,0 +1,109 @@
+# 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 timer
+
+maintainers:
+  - Thierry Reding <treding@nvidia.com>
+
+description: >
+  The Tegra timer provides 29-bit timer counters and a 32-bit timestamp
+  counter. Each NV timer selects its timing reference signal from the 1 MHz
+  reference generated by USEC, TSC or either clk_m or OSC. Each TMR can be
+  programmed to generate one-shot, periodic, or watchdog interrupts.
+
+
+properties:
+  compatible:
+    oneOf:
+      - const: nvidia,tegra186-timer
+        description: >
+          The Tegra186 timer provides ten 29-bit timer counters.
+      - const: nvidia,tegra234-timer
+        description: >
+          The Tegra234 timer provides sixteen 29-bit timer counters.
+
+  reg:
+    maxItems: 1
+
+  interrupts: true
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: nvidia,tegra186-timer
+    then:
+      properties:
+        interrupts:
+          maxItems: 10
+          description: >
+            One per each timer channels 0 through 9.
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: nvidia,tegra234-timer
+    then:
+      properties:
+        interrupts:
+          maxItems: 16
+          description: >
+            One per each timer channels 0 through 15.
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.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>;
+    };
+
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    timer@2080000 {
+        compatible = "nvidia,tegra234-timer";
+        reg = <0x02080000 0x00121000>;
+        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>,
+                     <GIC_SPI 10 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 11 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 12 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 14 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 15 IRQ_TYPE_LEVEL_HIGH>;
+    };
-- 
2.17.1

[PATCH v3 2/6] clocksource: Add Tegra186 timers support

[Kartik]

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>
Signed-off-by: Kartik <kkartik@nvidia.com>
---
 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 49960eb22f19..5bbc4aacff4c 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -156,6 +156,14 @@ 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 59c8909df9f3..64ab547de97b 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -36,6 +36,7 @@ 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");
-- 
2.17.1

[PATCH v3 3/6] clocksource/drivers/timer-tegra186: Add support for Tegra234 SoC

[Kartik]

The timer IP block present on Tegra234 SoC supports watchdog timer
functionality that can be used to recover from system hangs. The
watchdog timer uses a timer in the background for countdown.

Signed-off-by: Kartik <kkartik@nvidia.com>
---
 drivers/clocksource/timer-tegra186.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/clocksource/timer-tegra186.c b/drivers/clocksource/timer-tegra186.c
index 4515517c87a5..ea742889ee06 100644
--- a/drivers/clocksource/timer-tegra186.c
+++ b/drivers/clocksource/timer-tegra186.c
@@ -486,8 +486,14 @@ static const struct tegra186_timer_soc tegra186_timer = {
 	.num_wdts = 3,
 };
 
+static const struct tegra186_timer_soc tegra234_timer = {
+	.num_timers = 16,
+	.num_wdts = 3,
+};
+
 static const struct of_device_id tegra186_timer_of_match[] = {
 	{ .compatible = "nvidia,tegra186-timer", .data = &tegra186_timer },
+	{ .compatible = "nvidia,tegra234-timer", .data = &tegra234_timer },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, tegra186_timer_of_match);
-- 
2.17.1

[PATCH v3 4/6] arm64: tegra: Enable native timers on Tegra186

[Kartik]

Enable the native timers on Tegra186 chips to allow using the watchdog
functionality to recover from system hangs.

Signed-off-by: Kartik <kkartik@nvidia.com>
---
 arch/arm64/boot/dts/nvidia/tegra186.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/nvidia/tegra186.dtsi b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
index a87b52434939..a07acdaf345f 100644
--- a/arch/arm64/boot/dts/nvidia/tegra186.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
@@ -599,7 +599,7 @@
 			     <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
 			     <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>,
 			     <GIC_SPI 9 IRQ_TYPE_LEVEL_HIGH>;
-		status = "disabled";
+		status = "okay";
 	};
 
 	uarta: serial@3100000 {
-- 
2.17.1

[PATCH v3 5/6] arm64: tegra: Enable native timers on Tegra194

[Kartik]

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 and
enable the device tree node on Tegra194.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Kartik <kkartik@nvidia.com>
---
 arch/arm64/boot/dts/nvidia/tegra194.dtsi | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/arm64/boot/dts/nvidia/tegra194.dtsi b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
index 9566c6388ed9..4b37aec69448 100644
--- a/arch/arm64/boot/dts/nvidia/tegra194.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
@@ -698,6 +698,22 @@
 			};
 		};
 
+		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>;
+			status = "okay";
+		};
+
 		uarta: serial@3100000 {
 			compatible = "nvidia,tegra194-uart", "nvidia,tegra20-uart";
 			reg = <0x03100000 0x40>;
-- 
2.17.1

[PATCH v3 6/6] arm64: tegra: Enable native timers on Tegra234

[Kartik]

The native timers IP block found on NVIDIA Tegra SoCs implements a
watchdog timer that can be used to recover from system hangs. Add and
enable the device tree node on Tegra234.

Signed-off-by: Kartik <kkartik@nvidia.com>
---
 arch/arm64/boot/dts/nvidia/tegra234.dtsi | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/arch/arm64/boot/dts/nvidia/tegra234.dtsi b/arch/arm64/boot/dts/nvidia/tegra234.dtsi
index cf611eff7f6b..aa8ceb3c329b 100644
--- a/arch/arm64/boot/dts/nvidia/tegra234.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra234.dtsi
@@ -519,6 +519,28 @@
 			status = "okay";
 		};
 
+		timer@2080000 {
+			compatible = "nvidia,tegra234-timer";
+			reg = <0x02080000 0x00121000>;
+			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>,
+				     <GIC_SPI 10 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 11 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 12 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 14 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 15 IRQ_TYPE_LEVEL_HIGH>;
+			status = "okay";
+		};
+
 		gpio: gpio@2200000 {
 			compatible = "nvidia,tegra234-gpio";
 			reg-names = "security", "gpio";
-- 
2.17.1

Re: [PATCH v3 1/6] dt-bindings: timer: Add Tegra186 & Tegra234 Timer

[Rob Herring]

On Mon, 04 Jul 2022 13:43:37 +0530, Kartik wrote:
> The Tegra186 timer provides ten 29-bit timer counters and one 32-bit
> timestamp counter. The Tegra234 timer provides sixteen 29-bit timer
> counters and one 32-bit timestamp counter. Each NV timer selects its
> timing reference signal from the 1 MHz reference generated by USEC,
> TSC or either clk_m or OSC. Each TMR can be programmed to generate
> one-shot, periodic, or watchdog interrupts.
> 
> Signed-off-by: Kartik <kkartik@nvidia.com>
> ---
>  .../bindings/timer/nvidia,tegra186-timer.yaml | 109 ++++++++++++++++++
>  1 file changed, 109 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/timer/nvidia,tegra186-timer.yaml
> 

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

Re: [PATCH v3 0/6] Add watchdog timer support for Tegra186/194/234 SoCs

[Thierry Reding]

[-- Attachment #1: Type: text/plain, Size: 1513 bytes --]

On Mon, Jul 04, 2022 at 01:43:36PM +0530, Kartik wrote:
> The native timers IP block found on Tegra SoCs implements a watchdog
> timer that can be used to recover from system hangs. This series of
> patches adds support for watchdog timers available on Tegra186,
> Tegra194 and Tegra234 SOC's.
> 
> To keep the history intact, I added Tegra234 driver change as separate.
> The original patchset is an old one authored by Thierry.
> 
> Kartik (4):
>   dt-bindings: timer: Add Tegra186 & Tegra234 Timer
>   clocksource/drivers/timer-tegra186: Add support for Tegra234 SoC
>   arm64: tegra: Enable native timers on Tegra186
>   arm64: tegra: Enable native timers on Tegra234
> 
> Thierry Reding (2):
>   clocksource: Add Tegra186 timers support
>   arm64: tegra: Enable native timers on Tegra194
> 
>  .../bindings/timer/nvidia,tegra186-timer.yaml | 109 ++++
>  arch/arm64/boot/dts/nvidia/tegra186.dtsi      |   2 +-
>  arch/arm64/boot/dts/nvidia/tegra194.dtsi      |  16 +
>  arch/arm64/boot/dts/nvidia/tegra234.dtsi      |  22 +
>  drivers/clocksource/Kconfig                   |   8 +
>  drivers/clocksource/Makefile                  |   1 +
>  drivers/clocksource/timer-tegra186.c          | 514 ++++++++++++++++++
>  7 files changed, 671 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/devicetree/bindings/timer/nvidia,tegra186-timer.yaml
>  create mode 100644 drivers/clocksource/timer-tegra186.c

Applied patches 1 and 4-6 to the Tegra tree, thanks.

Thierry

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Re: [PATCH v3 3/6] clocksource/drivers/timer-tegra186: Add support for Tegra234 SoC

[Thierry Reding]

[-- Attachment #1: Type: text/plain, Size: 453 bytes --]

On Mon, Jul 04, 2022 at 01:43:39PM +0530, Kartik wrote:
> The timer IP block present on Tegra234 SoC supports watchdog timer
> functionality that can be used to recover from system hangs. The
> watchdog timer uses a timer in the background for countdown.
> 
> Signed-off-by: Kartik <kkartik@nvidia.com>
> ---
>  drivers/clocksource/timer-tegra186.c | 6 ++++++
>  1 file changed, 6 insertions(+)

Acked-by: Thierry Reding <treding@nvidia.com>

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Re: [PATCH v3 2/6] clocksource: Add Tegra186 timers support

[Thierry Reding]

[-- Attachment #1: Type: text/plain, Size: 979 bytes --]

On Mon, Jul 04, 2022 at 01:43:38PM +0530, Kartik wrote:
> 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>
> Signed-off-by: Kartik <kkartik@nvidia.com>
> ---
>  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

Daniel, any more work needed on this? Looks good to me, so:

Acked-by: Thierry Reding <treding@nvidia.com>

I've picked up patches 1 and 4-6 into the Tegra tree, so you only need
to take patches 2 and 3.

Thanks,
Thierry

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Re: [PATCH v3 2/6] clocksource: Add Tegra186 timers support

[Daniel Lezcano]

On 08/07/2022 16:47, Thierry Reding wrote:
> On Mon, Jul 04, 2022 at 01:43:38PM +0530, Kartik wrote:
>> 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>
>> Signed-off-by: Kartik <kkartik@nvidia.com>
>> ---
>>   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
> 
> Daniel, any more work needed on this? Looks good to me, so:
> 
> Acked-by: Thierry Reding <treding@nvidia.com>
> 
> I've picked up patches 1 and 4-6 into the Tegra tree, so you only need
> to take patches 2 and 3.

Applied, thanks


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[tip: timers/core] clocksource/drivers/timer-tegra186: Add support for Tegra234 SoC

[tip-bot2 for Kartik]

The following commit has been merged into the timers/core branch of tip:

Commit-ID:     07385a6055a8649593052703b1bfd6aef49db02a
Gitweb:        https://git.kernel.org/tip/07385a6055a8649593052703b1bfd6aef49db02a
Author:        Kartik <kkartik@nvidia.com>
AuthorDate:    Mon, 04 Jul 2022 13:43:39 +05:30
Committer:     Daniel Lezcano <daniel.lezcano@linaro.org>
CommitterDate: Sat, 16 Jul 2022 00:38:50 +02:00

clocksource/drivers/timer-tegra186: Add support for Tegra234 SoC

The timer IP block present on Tegra234 SoC supports watchdog timer
functionality that can be used to recover from system hangs. The
watchdog timer uses a timer in the background for countdown.

Signed-off-by: Kartik <kkartik@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/1656922422-25823-4-git-send-email-kkartik@nvidia.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/timer-tegra186.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/clocksource/timer-tegra186.c b/drivers/clocksource/timer-tegra186.c
index 4515517..ea74288 100644
--- a/drivers/clocksource/timer-tegra186.c
+++ b/drivers/clocksource/timer-tegra186.c
@@ -486,8 +486,14 @@ static const struct tegra186_timer_soc tegra186_timer = {
 	.num_wdts = 3,
 };
 
+static const struct tegra186_timer_soc tegra234_timer = {
+	.num_timers = 16,
+	.num_wdts = 3,
+};
+
 static const struct of_device_id tegra186_timer_of_match[] = {
 	{ .compatible = "nvidia,tegra186-timer", .data = &tegra186_timer },
+	{ .compatible = "nvidia,tegra234-timer", .data = &tegra234_timer },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, tegra186_timer_of_match);

[tip: timers/core] clocksource: Add Tegra186 timers support

[tip-bot2 for Thierry Reding]

The following commit has been merged into the timers/core branch of tip:

Commit-ID:     42cee19a9f839f2d60f1cd237d6905d8649127aa
Gitweb:        https://git.kernel.org/tip/42cee19a9f839f2d60f1cd237d6905d8649127aa
Author:        Thierry Reding <treding@nvidia.com>
AuthorDate:    Mon, 04 Jul 2022 13:43:38 +05:30
Committer:     Daniel Lezcano <daniel.lezcano@linaro.org>
CommitterDate: Sat, 16 Jul 2022 00:38:50 +02:00

clocksource: Add Tegra186 timers support

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>
Signed-off-by: Kartik <kkartik@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/1656922422-25823-3-git-send-email-kkartik@nvidia.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 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 0367a1c..2dcdf02 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -150,6 +150,14 @@ 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 9c85ee2..685430d 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -36,6 +36,7 @@ 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 0000000..4515517
--- /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");