[PATCH v4 0/4] ARM: meson: watchdog driver

[PATCH v4 0/4] ARM: meson: watchdog driver

[Carlo Caione]

This patchset adds support for the watchdog found on Amlogic MesonX SoCs. The
watchdog is used also to reboot the device.

DTSI and multi_v7_defconfig are updated and proper documentation is added.

No documentation is provided by Amlogic, the code is reverse-engineered by the
code available at http://openlinux.amlogic.com:8000/download/

This patchset depends on:
[1] [PATCH 0/6] ARM: meson: initial support for MesonX SoCs
[2] [PATCH 0/2] ARM: meson: add clocksource support

Changes since v3:
* addressed checkpatch warning

Changes since v2:
* changed compatible to "amlogic,meson6-wdt"
* removed useless code
* code refactored

Changes since v1:
* added restart handler support

Carlo Caione (4):
  ARM: docs: add documentation binding for meson watchdog
  ARM: meson: add watchdog driver
  ARM: DTS: meson: update DTSI to add watchdog node
  ARM: defconfig: update multi_v7_defconfig

 .../devicetree/bindings/watchdog/meson6-wdt.txt    |  13 ++
 arch/arm/boot/dts/meson.dtsi                       |   5 +
 arch/arm/configs/multi_v7_defconfig                |   1 +
 drivers/watchdog/Kconfig                           |  10 +
 drivers/watchdog/Makefile                          |   1 +
 drivers/watchdog/meson_wdt.c                       | 236 +++++++++++++++++++++
 6 files changed, 266 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/meson6-wdt.txt
 create mode 100644 drivers/watchdog/meson_wdt.c

-- 
1.9.1

[PATCH v4 1/4] ARM: docs: add documentation binding for meson watchdog

[Carlo Caione]

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Carlo Caione <carlo@caione.org>
---
 Documentation/devicetree/bindings/watchdog/meson6-wdt.txt | 13 +++++++++++++
 1 file changed, 13 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/meson6-wdt.txt

diff --git a/Documentation/devicetree/bindings/watchdog/meson6-wdt.txt b/Documentation/devicetree/bindings/watchdog/meson6-wdt.txt
new file mode 100644
index 0000000..9200fc2
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/meson6-wdt.txt
@@ -0,0 +1,13 @@
+Meson SoCs Watchdog timer
+
+Required properties:
+
+- compatible : should be "amlogic,meson6-wdt"
+- reg : Specifies base physical address and size of the registers.
+
+Example:
+
+wdt: watchdog at c1109900 {
+	compatible = "amlogic,meson6-wdt";
+	reg = <0xc1109900 0x8>;
+};
-- 
1.9.1

[PATCH v4 2/4] ARM: meson: add watchdog driver

[Carlo Caione]

This patch adds the watchdog driver for the Amlogic Meson SoCs used also
to reboot the device.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Carlo Caione <carlo@caione.org>
---
 drivers/watchdog/Kconfig     |  10 ++
 drivers/watchdog/Makefile    |   1 +
 drivers/watchdog/meson_wdt.c | 236 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 247 insertions(+)
 create mode 100644 drivers/watchdog/meson_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index f57312f..836cb00 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -443,6 +443,16 @@ config TEGRA_WATCHDOG
 	  To compile this driver as a module, choose M here: the
 	  module will be called tegra_wdt.
 
+config MESON_WATCHDOG
+	tristate "Amlogic Meson SoCs watchdog support"
+	depends on ARCH_MESON
+	select WATCHDOG_CORE
+	help
+	  Say Y here to include support for the watchdog timer
+	  in Amlogic Meson SoCs.
+	  To compile this driver as a module, choose M here: the
+	  module will be called meson_wdt.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 468c320..e7a9259 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_MOXART_WDT) += moxart_wdt.o
 obj-$(CONFIG_SIRFSOC_WATCHDOG) += sirfsoc_wdt.o
 obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o
 obj-$(CONFIG_TEGRA_WATCHDOG) += tegra_wdt.o
+obj-$(CONFIG_MESON_WATCHDOG) += meson_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/meson_wdt.c b/drivers/watchdog/meson_wdt.c
new file mode 100644
index 0000000..37f9f5ec
--- /dev/null
+++ b/drivers/watchdog/meson_wdt.c
@@ -0,0 +1,236 @@
+/*
+ *      Meson Watchdog Driver
+ *
+ *      Copyright (c) 2014 Carlo Caione
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/notifier.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+#define DRV_NAME		"meson_wdt"
+
+#define MESON_WDT_TC		0x00
+#define MESON_WDT_TC_EN		BIT(22)
+#define MESON_WDT_TC_TM_MASK	0x3fffff
+#define MESON_WDT_DC_RESET	(3 << 24)
+
+#define MESON_WDT_RESET		0x04
+
+#define MESON_WDT_TIMEOUT	30
+#define MESON_WDT_MIN_TIMEOUT	1
+#define MESON_WDT_MAX_TIMEOUT	(MESON_WDT_TC_TM_MASK / 100000)
+
+#define MESON_SEC_TO_TC(s)	((s) * 100000)
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+static unsigned int timeout = MESON_WDT_TIMEOUT;
+
+struct meson_wdt_dev {
+	struct watchdog_device wdt_dev;
+	void __iomem *wdt_base;
+	struct notifier_block restart_handler;
+};
+
+static int meson_restart_handle(struct notifier_block *this, unsigned long mode,
+				void *cmd)
+{
+	u32 tc_reboot = MESON_WDT_DC_RESET | MESON_WDT_TC_EN | 100;
+	struct meson_wdt_dev *meson_wdt = container_of(this,
+						       struct meson_wdt_dev,
+						       restart_handler);
+
+	while (1) {
+		writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC);
+		mdelay(5);
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int meson_wdt_ping(struct watchdog_device *wdt_dev)
+{
+	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
+
+	writel(0, meson_wdt->wdt_base + MESON_WDT_RESET);
+
+	return 0;
+}
+
+static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev,
+				     unsigned int timeout)
+{
+	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
+	u32 reg;
+
+	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
+	reg &= ~MESON_WDT_TC_TM_MASK;
+	reg |= MESON_SEC_TO_TC(timeout);
+	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
+}
+
+static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev,
+				 unsigned int timeout)
+{
+	wdt_dev->timeout = timeout;
+
+	meson_wdt_change_timeout(wdt_dev, timeout);
+	meson_wdt_ping(wdt_dev);
+
+	return 0;
+}
+
+static int meson_wdt_stop(struct watchdog_device *wdt_dev)
+{
+	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
+	u32 reg;
+
+	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
+	reg &= ~MESON_WDT_TC_EN;
+	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
+
+	return 0;
+}
+
+static int meson_wdt_start(struct watchdog_device *wdt_dev)
+{
+	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
+	u32 reg;
+
+	meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout);
+	meson_wdt_ping(wdt_dev);
+
+	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
+	reg |= MESON_WDT_TC_EN;
+	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
+
+	return 0;
+}
+
+static const struct watchdog_info meson_wdt_info = {
+	.identity	= DRV_NAME,
+	.options	= WDIOF_SETTIMEOUT |
+			  WDIOF_KEEPALIVEPING |
+			  WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_ops meson_wdt_ops = {
+	.owner		= THIS_MODULE,
+	.start		= meson_wdt_start,
+	.stop		= meson_wdt_stop,
+	.ping		= meson_wdt_ping,
+	.set_timeout	= meson_wdt_set_timeout,
+};
+
+static int meson_wdt_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct meson_wdt_dev *meson_wdt;
+	int err;
+
+	meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL);
+	if (!meson_wdt)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	meson_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(meson_wdt->wdt_base))
+		return PTR_ERR(meson_wdt->wdt_base);
+
+	meson_wdt->wdt_dev.parent = &pdev->dev;
+	meson_wdt->wdt_dev.info = &meson_wdt_info;
+	meson_wdt->wdt_dev.ops = &meson_wdt_ops;
+	meson_wdt->wdt_dev.timeout = MESON_WDT_TIMEOUT;
+	meson_wdt->wdt_dev.max_timeout = MESON_WDT_MAX_TIMEOUT;
+	meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT;
+
+	watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt);
+
+	watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, &pdev->dev);
+	watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout);
+
+	meson_wdt_stop(&meson_wdt->wdt_dev);
+
+	err = watchdog_register_device(&meson_wdt->wdt_dev);
+	if (err)
+		return err;
+
+	platform_set_drvdata(pdev, meson_wdt);
+
+	meson_wdt->restart_handler.notifier_call = meson_restart_handle;
+	meson_wdt->restart_handler.priority = 128;
+	err = register_restart_handler(&meson_wdt->restart_handler);
+	if (err)
+		dev_err(&pdev->dev,
+			"cannot register restart handler (err=%d)\n", err);
+
+	dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
+		 meson_wdt->wdt_dev.timeout, nowayout);
+
+	return 0;
+}
+
+static int meson_wdt_remove(struct platform_device *pdev)
+{
+	struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);
+
+	unregister_restart_handler(&meson_wdt->restart_handler);
+
+	watchdog_unregister_device(&meson_wdt->wdt_dev);
+
+	return 0;
+}
+
+static void meson_wdt_shutdown(struct platform_device *pdev)
+{
+	struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);
+
+	meson_wdt_stop(&meson_wdt->wdt_dev);
+}
+
+static const struct of_device_id meson_wdt_dt_ids[] = {
+	{ .compatible = "amlogic,meson6-wdt" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);
+
+static struct platform_driver meson_wdt_driver = {
+	.probe		= meson_wdt_probe,
+	.remove		= meson_wdt_remove,
+	.shutdown	= meson_wdt_shutdown,
+	.driver		= {
+		.owner		= THIS_MODULE,
+		.name		= DRV_NAME,
+		.of_match_table	= meson_wdt_dt_ids,
+	},
+};
+
+module_platform_driver(meson_wdt_driver);
+
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
+
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+		 "Watchdog cannot be stopped once started (default="
+		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
+MODULE_DESCRIPTION("Meson Watchdog Timer Driver");
-- 
1.9.1

[PATCH v4 3/4] ARM: DTS: meson: update DTSI to add watchdog node

[Carlo Caione]

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Carlo Caione <carlo@caione.org>
---
 arch/arm/boot/dts/meson.dtsi | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/boot/dts/meson.dtsi b/arch/arm/boot/dts/meson.dtsi
index 55feb14..e6539ea 100644
--- a/arch/arm/boot/dts/meson.dtsi
+++ b/arch/arm/boot/dts/meson.dtsi
@@ -70,6 +70,11 @@
 		#size-cells = <1>;
 		ranges;
 
+		wdt: watchdog at c1109900 {
+			compatible = "amlogic,meson6-wdt";
+			reg = <0xc1109900 0x8>;
+		};
+
 		uart_AO: serial at c81004c0 {
 			compatible = "amlogic,meson-uart";
 			reg = <0xc81004c0 0x14>;
-- 
1.9.1

[PATCH v4 4/4] ARM: defconfig: update multi_v7_defconfig

[Carlo Caione]

Update the multi_v7_defconfig enabling the watchdog driver for Meson
SoCs.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Carlo Caione <carlo@caione.org>
---
 arch/arm/configs/multi_v7_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/configs/multi_v7_defconfig b/arch/arm/configs/multi_v7_defconfig
index 5b44796..560e6a9 100644
--- a/arch/arm/configs/multi_v7_defconfig
+++ b/arch/arm/configs/multi_v7_defconfig
@@ -242,6 +242,7 @@ CONFIG_ST_THERMAL_MEMMAP=y
 CONFIG_WATCHDOG=y
 CONFIG_ORION_WATCHDOG=y
 CONFIG_SUNXI_WATCHDOG=y
+CONFIG_MESON_WATCHDOG=y
 CONFIG_MFD_AS3722=y
 CONFIG_MFD_BCM590XX=y
 CONFIG_MFD_CROS_EC=y
-- 
1.9.1

[PATCH v4 3/4] ARM: DTS: meson: update DTSI to add watchdog node

[Carlo Caione]

On Sat, Sep 20, 2014 at 7:06 PM, Carlo Caione <carlo@caione.org> wrote:
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> Signed-off-by: Carlo Caione <carlo@caione.org>
> ---
>  arch/arm/boot/dts/meson.dtsi | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/arch/arm/boot/dts/meson.dtsi b/arch/arm/boot/dts/meson.dtsi
> index 55feb14..e6539ea 100644
> --- a/arch/arm/boot/dts/meson.dtsi
> +++ b/arch/arm/boot/dts/meson.dtsi
> @@ -70,6 +70,11 @@
>                 #size-cells = <1>;
>                 ranges;
>
> +               wdt: watchdog at c1109900 {
> +                       compatible = "amlogic,meson6-wdt";
> +                       reg = <0xc1109900 0x8>;
> +               };
> +
>                 uart_AO: serial at c81004c0 {
>                         compatible = "amlogic,meson-uart";
>                         reg = <0xc81004c0 0x14>;

Hi Arnd and Guenter,
who is supposed to take in this patch? The basic support for the SoC
is already in the arm-soc tree (thanks Arnd) and the other three
patches of this patchset are going in through Guenter tree (thanks
Guenter).

BR,

-- 
Carlo Caione

[PATCH v4 3/4] ARM: DTS: meson: update DTSI to add watchdog node

[Arnd Bergmann]

On Friday 26 September 2014 10:04:45 Carlo Caione wrote:
> Hi Arnd and Guenter,
> who is supposed to take in this patch? The basic support for the SoC
> is already in the arm-soc tree (thanks Arnd) and the other three
> patches of this patchset are going in through Guenter tree (thanks
> Guenter).
> 

It should go through the arm-soc tree.

	Arnd

[PATCH v4 3/4] ARM: DTS: meson: update DTSI to add watchdog node

[Carlo Caione]

On Fri, Sep 26, 2014 at 11:16 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Friday 26 September 2014 10:04:45 Carlo Caione wrote:
>> Hi Arnd and Guenter,
>> who is supposed to take in this patch? The basic support for the SoC
>> is already in the arm-soc tree (thanks Arnd) and the other three
>> patches of this patchset are going in through Guenter tree (thanks
>> Guenter).
>>
>
> It should go through the arm-soc tree.

Could you take it?

Thanks,

-- 
Carlo Caione

[PATCH v4 3/4] ARM: DTS: meson: update DTSI to add watchdog node

[Carlo Caione]

On Fri, Sep 26, 2014 at 11:16 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Friday 26 September 2014 10:04:45 Carlo Caione wrote:
>> Hi Arnd and Guenter,
>> who is supposed to take in this patch? The basic support for the SoC
>> is already in the arm-soc tree (thanks Arnd) and the other three
>> patches of this patchset are going in through Guenter tree (thanks
>> Guenter).
>>
>
> It should go through the arm-soc tree.

Arnd,
do you want me to submit a standalone patch for this?

Thanks,

-- 
Carlo Caione