[PATCH 0/4] Add i.MX8QXP system controller watchdog support

[PATCH 0/4] Add i.MX8QXP system controller watchdog support

[Anson Huang]

i.MX8QXP is an ARMv8 Cortex-A35 SoC with a Cortex-M4 system controller inside,
the system controller manages overall power, clock, secure RTC and watchdog
etc., so Linux kernel running on A35 needs to communicate with system
controller for watchdog operation, this system controller watchdog will
call SMC to trap to EL3 secure world ARM-Trusted-Firmware and then it will
request system controller to do the watchdog operation via IPC.

Below are the patch dependency:

The dt-binding and imx8qxp.dtsi patch are based on my thermal patch series as below:
https://patchwork.kernel.org/patch/10800699/

Anson Huang (4):
  dt-bindings: fsl: scu: add watchdog binding
  watchdog: imx_sc: Add i.MX system controller watchdog support
  arm64: defconfig: add support for i.MX system controller watchdog
  arm64: dts: freescale: imx8qxp: add watchdog support

 .../devicetree/bindings/arm/freescale/fsl,scu.txt  |  10 +
 arch/arm64/boot/dts/freescale/imx8qxp.dtsi         |   4 +
 arch/arm64/configs/defconfig                       |   1 +
 drivers/watchdog/Kconfig                           |  13 ++
 drivers/watchdog/Makefile                          |   1 +
 drivers/watchdog/imx_sc_wdt.c                      | 210 +++++++++++++++++++++
 6 files changed, 239 insertions(+)
 create mode 100644 drivers/watchdog/imx_sc_wdt.c

-- 
2.7.4

[PATCH 1/4] dt-bindings: fsl: scu: add watchdog binding

[Anson Huang]

Add i.MX8QXP system controller watchdog binding.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
Note: this patch is based on my thermal patch series: https://patchwork.kernel.org/patch/10800699/
---
 Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
index 42120cb..a3ef861 100644
--- a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
+++ b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
@@ -140,6 +140,12 @@ Required properties:
 			   resource id for thermal driver to get temperature via
 			   SCU IPC.
 
+WatchDog bindings based on SCU Message Protocol
+------------------------------------------------------------
+
+Required properties:
+- compatible: should be "fsl,imx8qxp-sc-wdt";
+
 Example (imx8qxp):
 -------------
 lsio_mu1: mailbox@5d1c0000 {
@@ -194,6 +200,10 @@ firmware {
 			tsens-num = <1>;
 			#thermal-sensor-cells = <1>;
 		};
+
+		wdog: wdog {
+			compatible = "fsl,imx8qxp-sc-wdt";
+		};
 	};
 };
 
-- 
2.7.4

[PATCH 2/4] watchdog: imx_sc: Add i.MX system controller watchdog support

[Anson Huang]

i.MX8QXP is an ARMv8 SoC which has a Cortex-M4 system controller
inside, the system controller is in charge of controlling power,
clock and watchdog etc..

This patch adds i.MX system controller watchdog driver support,
watchdog operation needs to be done in secure EL3 mode via
ARM-Trusted-Firmware, using SMC call, CPU will trap into
ARM-Trusted-Firmware and then it will request system controller
to do watchdog operation via IPC.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
 drivers/watchdog/Kconfig      |  13 +++
 drivers/watchdog/Makefile     |   1 +
 drivers/watchdog/imx_sc_wdt.c | 210 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 224 insertions(+)
 create mode 100644 drivers/watchdog/imx_sc_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 65c3c42..5c5b8ba 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -625,6 +625,19 @@ config IMX2_WDT
 	  To compile this driver as a module, choose M here: the
 	  module will be called imx2_wdt.
 
+config IMX_SC_WDT
+	tristate "IMX SC Watchdog"
+	depends on ARCH_MXC || COMPILE_TEST
+	select WATCHDOG_CORE
+	help
+	  This is the driver for the system controller watchdog
+	  on the NXP i.MX SoCs with system controller inside.
+	  If you have one of these processors and wish to have
+	  watchdog support enabled, say Y, otherwise say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called imx_sc_wdt.
+
 config UX500_WATCHDOG
 	tristate "ST-Ericsson Ux500 watchdog"
 	depends on MFD_DB8500_PRCMU
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 4e78a8c..0c9da63 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
 obj-$(CONFIG_TS4800_WATCHDOG) += ts4800_wdt.o
 obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
 obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
+obj-$(CONFIG_IMX_SC_WDT) += imx_sc_wdt.o
 obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
 obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
 obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
diff --git a/drivers/watchdog/imx_sc_wdt.c b/drivers/watchdog/imx_sc_wdt.c
new file mode 100644
index 0000000..ae52e34
--- /dev/null
+++ b/drivers/watchdog/imx_sc_wdt.c
@@ -0,0 +1,210 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2018-2019 NXP.
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/watchdog.h>
+
+#define DEFAULT_TIMEOUT 60
+/*
+ * Software timer tick implemented in scfw side, support 10ms to 0xffffffff ms
+ * in theory, but for normal case, 1s~128s is enough, you can change this max
+ * value in case it's not enough.
+ */
+#define MAX_TIMEOUT 128
+
+#define IMX_SIP_TIMER			0xC2000002
+#define IMX_SIP_TIMER_START_WDOG		0x01
+#define IMX_SIP_TIMER_STOP_WDOG		0x02
+#define IMX_SIP_TIMER_SET_WDOG_ACT	0x03
+#define IMX_SIP_TIMER_PING_WDOG		0x04
+#define IMX_SIP_TIMER_SET_TIMEOUT_WDOG	0x05
+#define IMX_SIP_TIMER_GET_WDOG_STAT	0x06
+#define IMX_SIP_TIMER_SET_PRETIME_WDOG	0x07
+
+#define SC_TIMER_WDOG_ACTION_PARTITION	0
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0000);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static unsigned int timeout = DEFAULT_TIMEOUT;
+module_param(timeout, uint, 0000);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
+		 __MODULE_STRING(DEFAULT_TIMEOUT) ")");
+
+static struct watchdog_device imx_sc_wdd;
+
+static int imx_sc_wdt_ping(struct watchdog_device *wdog)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_PING_WDOG,
+		      0, 0, 0, 0, 0, 0, &res);
+
+	return res.a0;
+}
+
+static int imx_sc_wdt_start(struct watchdog_device *wdog)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_START_WDOG,
+		      0, 0, 0, 0, 0, 0, &res);
+	if (res.a0)
+		return res.a0;
+
+	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_WDOG_ACT,
+		      SC_TIMER_WDOG_ACTION_PARTITION,
+		      0, 0, 0, 0, 0, &res);
+
+	return res.a0;
+}
+
+static int imx_sc_wdt_stop(struct watchdog_device *wdog)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_STOP_WDOG,
+		      0, 0, 0, 0, 0, 0, &res);
+
+	return res.a0;
+}
+
+static int imx_sc_wdt_set_timeout(struct watchdog_device *wdog,
+				unsigned int timeout)
+{
+	struct arm_smccc_res res;
+
+	wdog->timeout = timeout;
+	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_TIMEOUT_WDOG,
+		      timeout * 1000, 0, 0, 0, 0, 0, &res);
+
+	return res.a0;
+}
+
+static const struct watchdog_ops imx_sc_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = imx_sc_wdt_start,
+	.stop  = imx_sc_wdt_stop,
+	.ping  = imx_sc_wdt_ping,
+	.set_timeout = imx_sc_wdt_set_timeout,
+};
+
+static const struct watchdog_info imx_sc_wdt_info = {
+	.identity	= "i.MX SC watchdog timer",
+	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+			  WDIOF_MAGICCLOSE | WDIOF_PRETIMEOUT,
+};
+
+#ifdef CONFIG_PM_SLEEP
+static int imx_sc_wdt_suspend(struct device *dev)
+{
+	if (test_bit(WDOG_ACTIVE, &imx_sc_wdd.status))
+		imx_sc_wdt_stop(&imx_sc_wdd);
+
+	return 0;
+}
+
+static int imx_sc_wdt_resume(struct device *dev)
+{
+	if (test_bit(WDOG_ACTIVE, &imx_sc_wdd.status))
+		imx_sc_wdt_start(&imx_sc_wdd);
+
+	return 0;
+}
+
+static const struct dev_pm_ops imx_sc_wdt_pm_ops = {
+	.suspend = imx_sc_wdt_suspend,
+	.resume = imx_sc_wdt_resume,
+};
+
+#define IMX_SC_WDT_PM_OPS	(&imx_sc_wdt_pm_ops)
+
+#else
+
+#define IMX_SC_WDT_PM_OPS	NULL
+
+#endif
+
+static int imx_sc_wdt_probe(struct platform_device *pdev)
+{
+	struct watchdog_device *wdt = &imx_sc_wdd;
+	int err;
+
+	platform_set_drvdata(pdev, wdt);
+
+	wdt->info = &imx_sc_wdt_info;
+	wdt->ops = &imx_sc_wdt_ops;
+	wdt->min_timeout = 1;
+	wdt->max_timeout = MAX_TIMEOUT;
+	wdt->parent = &pdev->dev;
+	watchdog_set_drvdata(wdt, NULL);
+
+	err = watchdog_init_timeout(wdt, DEFAULT_TIMEOUT, &pdev->dev);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to init the wdog timeout:%d\n",
+			err);
+		return err;
+	}
+
+	err = watchdog_register_device(wdt);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to register watchdog device\n");
+		return err;
+	}
+
+	return 0;
+}
+
+static int imx_sc_wdt_remove(struct platform_device *pdev)
+{
+	struct watchdog_device *wdt = platform_get_drvdata(pdev);
+
+	imx_sc_wdt_stop(wdt);
+
+	watchdog_unregister_device(wdt);
+
+	return 0;
+}
+
+static void imx_sc_wdt_shutdown(struct platform_device *pdev)
+{
+	struct watchdog_device *wdt = platform_get_drvdata(pdev);
+
+	if (watchdog_active(wdt))
+		imx_sc_wdt_stop(wdt);
+}
+
+static const struct of_device_id imx_sc_wdt_dt_ids[] = {
+	{ .compatible = "fsl,imx8qxp-sc-wdt", },
+	{ /*sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, imx_sc_wdt_dt_ids);
+
+static struct platform_driver imx_sc_wdt_driver = {
+	.probe		= imx_sc_wdt_probe,
+	.remove		= imx_sc_wdt_remove,
+	.shutdown	= imx_sc_wdt_shutdown,
+	.driver		= {
+		.name	= "imx-sc-wdt",
+		.of_match_table = imx_sc_wdt_dt_ids,
+		.pm	= IMX_SC_WDT_PM_OPS,
+	},
+};
+
+module_platform_driver(imx_sc_wdt_driver);
+
+MODULE_AUTHOR("Robin Gong <yibin.gong@nxp.com>");
+MODULE_DESCRIPTION("NXP i.MX system controller watchdog driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

[PATCH 3/4] arm64: defconfig: add support for i.MX system controller watchdog

[Anson Huang]

Enable CONFIG_IMX_SC_WDT as module to support i.MX system
controller watchdog.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
 arch/arm64/configs/defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index 2d9c390..690f4ba 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -427,6 +427,7 @@ CONFIG_WATCHDOG=y
 CONFIG_ARM_SP805_WATCHDOG=y
 CONFIG_S3C2410_WATCHDOG=y
 CONFIG_IMX2_WDT=y
+CONFIG_IMX_SC_WDT=m
 CONFIG_MESON_GXBB_WATCHDOG=m
 CONFIG_MESON_WATCHDOG=m
 CONFIG_RENESAS_WDT=y
-- 
2.7.4

[PATCH 4/4] arm64: dts: freescale: imx8qxp: add watchdog support

[Anson Huang]

Add i.MX8QXP system controller watchdog support.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
Note: this patch is based on my thermal patch series: https://patchwork.kernel.org/patch/10800699/
---
 arch/arm64/boot/dts/freescale/imx8qxp.dtsi | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/imx8qxp.dtsi b/arch/arm64/boot/dts/freescale/imx8qxp.dtsi
index 1bf0e3b..087ba41 100644
--- a/arch/arm64/boot/dts/freescale/imx8qxp.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8qxp.dtsi
@@ -155,6 +155,10 @@
 			tsens-num = <1>;
 			#thermal-sensor-cells = <1>;
 		};
+
+		wdog: wdog {
+			compatible = "fsl,imx8qxp-sc-wdt";
+		};
 	};
 
 	timer {
-- 
2.7.4

Re: [PATCH 2/4] watchdog: imx_sc: Add i.MX system controller watchdog support

[Guenter Roeck]

On 2/14/19 3:44 AM, Anson Huang wrote:
> i.MX8QXP is an ARMv8 SoC which has a Cortex-M4 system controller
> inside, the system controller is in charge of controlling power,
> clock and watchdog etc..
> 
> This patch adds i.MX system controller watchdog driver support,
> watchdog operation needs to be done in secure EL3 mode via
> ARM-Trusted-Firmware, using SMC call, CPU will trap into
> ARM-Trusted-Firmware and then it will request system controller
> to do watchdog operation via IPC.
> 
> Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> ---
>   drivers/watchdog/Kconfig      |  13 +++
>   drivers/watchdog/Makefile     |   1 +
>   drivers/watchdog/imx_sc_wdt.c | 210 ++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 224 insertions(+)
>   create mode 100644 drivers/watchdog/imx_sc_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 65c3c42..5c5b8ba 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -625,6 +625,19 @@ config IMX2_WDT
>   	  To compile this driver as a module, choose M here: the
>   	  module will be called imx2_wdt.
>   
> +config IMX_SC_WDT
> +	tristate "IMX SC Watchdog"
> +	depends on ARCH_MXC || COMPILE_TEST
> +	select WATCHDOG_CORE
> +	help
> +	  This is the driver for the system controller watchdog
> +	  on the NXP i.MX SoCs with system controller inside.
> +	  If you have one of these processors and wish to have
> +	  watchdog support enabled, say Y, otherwise say N.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called imx_sc_wdt.
> +
>   config UX500_WATCHDOG
>   	tristate "ST-Ericsson Ux500 watchdog"
>   	depends on MFD_DB8500_PRCMU
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 4e78a8c..0c9da63 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -68,6 +68,7 @@ obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
>   obj-$(CONFIG_TS4800_WATCHDOG) += ts4800_wdt.o
>   obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
>   obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
> +obj-$(CONFIG_IMX_SC_WDT) += imx_sc_wdt.o
>   obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
>   obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
>   obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
> diff --git a/drivers/watchdog/imx_sc_wdt.c b/drivers/watchdog/imx_sc_wdt.c
> new file mode 100644
> index 0000000..ae52e34
> --- /dev/null
> +++ b/drivers/watchdog/imx_sc_wdt.c
> @@ -0,0 +1,210 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright 2018-2019 NXP.
> + */
> +
> +#include <linux/arm-smccc.h>
> +#include <linux/io.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/reboot.h>
> +#include <linux/watchdog.h>
> +
> +#define DEFAULT_TIMEOUT 60
> +/*
> + * Software timer tick implemented in scfw side, support 10ms to 0xffffffff ms
> + * in theory, but for normal case, 1s~128s is enough, you can change this max
> + * value in case it's not enough.
> + */
> +#define MAX_TIMEOUT 128
> +
> +#define IMX_SIP_TIMER			0xC2000002
> +#define IMX_SIP_TIMER_START_WDOG		0x01
> +#define IMX_SIP_TIMER_STOP_WDOG		0x02
> +#define IMX_SIP_TIMER_SET_WDOG_ACT	0x03
> +#define IMX_SIP_TIMER_PING_WDOG		0x04
> +#define IMX_SIP_TIMER_SET_TIMEOUT_WDOG	0x05
> +#define IMX_SIP_TIMER_GET_WDOG_STAT	0x06
> +#define IMX_SIP_TIMER_SET_PRETIME_WDOG	0x07
> +
> +#define SC_TIMER_WDOG_ACTION_PARTITION	0
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, bool, 0000);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
> +		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +
> +static unsigned int timeout = DEFAULT_TIMEOUT;
> +module_param(timeout, uint, 0000);
> +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
> +		 __MODULE_STRING(DEFAULT_TIMEOUT) ")");
> +
> +static struct watchdog_device imx_sc_wdd;
> +
> +static int imx_sc_wdt_ping(struct watchdog_device *wdog)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_PING_WDOG,
> +		      0, 0, 0, 0, 0, 0, &res);
> +
> +	return res.a0;
> +}
> +
> +static int imx_sc_wdt_start(struct watchdog_device *wdog)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_START_WDOG,
> +		      0, 0, 0, 0, 0, 0, &res);
> +	if (res.a0)
> +		return res.a0;
> +
> +	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_WDOG_ACT,
> +		      SC_TIMER_WDOG_ACTION_PARTITION,
> +		      0, 0, 0, 0, 0, &res);
> +
> +	return res.a0;
> +}
> +
> +static int imx_sc_wdt_stop(struct watchdog_device *wdog)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_STOP_WDOG,
> +		      0, 0, 0, 0, 0, 0, &res);
> +
> +	return res.a0;
> +}
> +
> +static int imx_sc_wdt_set_timeout(struct watchdog_device *wdog,
> +				unsigned int timeout)
> +{
> +	struct arm_smccc_res res;
> +
> +	wdog->timeout = timeout;
> +	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_TIMEOUT_WDOG,
> +		      timeout * 1000, 0, 0, 0, 0, 0, &res);
> +
> +	return res.a0;
> +}
> +
> +static const struct watchdog_ops imx_sc_wdt_ops = {
> +	.owner = THIS_MODULE,
> +	.start = imx_sc_wdt_start,
> +	.stop  = imx_sc_wdt_stop,
> +	.ping  = imx_sc_wdt_ping,
> +	.set_timeout = imx_sc_wdt_set_timeout,
> +};
> +
> +static const struct watchdog_info imx_sc_wdt_info = {
> +	.identity	= "i.MX SC watchdog timer",
> +	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
> +			  WDIOF_MAGICCLOSE | WDIOF_PRETIMEOUT,
> +};
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int imx_sc_wdt_suspend(struct device *dev)
> +{
> +	if (test_bit(WDOG_ACTIVE, &imx_sc_wdd.status))
> +		imx_sc_wdt_stop(&imx_sc_wdd);
> +

What is wrong with watchdog_active() ? It is used below ?

> +	return 0;
> +}
> +
> +static int imx_sc_wdt_resume(struct device *dev)
> +{
> +	if (test_bit(WDOG_ACTIVE, &imx_sc_wdd.status))
> +		imx_sc_wdt_start(&imx_sc_wdd);
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops imx_sc_wdt_pm_ops = {
> +	.suspend = imx_sc_wdt_suspend,
> +	.resume = imx_sc_wdt_resume,
> +};
> +
> +#define IMX_SC_WDT_PM_OPS	(&imx_sc_wdt_pm_ops)
> +
> +#else
> +
> +#define IMX_SC_WDT_PM_OPS	NULL
> +
> +#endif
> +
> +static int imx_sc_wdt_probe(struct platform_device *pdev)
> +{
> +	struct watchdog_device *wdt = &imx_sc_wdd;

Please use devm_kzalloc() and drop the static variable. You can use
dev_get_drvdata() to access it where needed.

> +	int err;
> +
> +	platform_set_drvdata(pdev, wdt);
> +
> +	wdt->info = &imx_sc_wdt_info;
> +	wdt->ops = &imx_sc_wdt_ops;
> +	wdt->min_timeout = 1;
> +	wdt->max_timeout = MAX_TIMEOUT;
> +	wdt->parent = &pdev->dev;
> +	watchdog_set_drvdata(wdt, NULL);
> +
This is quite pointless.

> +	err = watchdog_init_timeout(wdt, DEFAULT_TIMEOUT, &pdev->dev);
> +	if (err) {
> +		dev_err(&pdev->dev, "Failed to init the wdog timeout:%d\n",
> +			err);
> +		return err;
> +	}
> +
> +	err = watchdog_register_device(wdt);
> +	if (err) {
> +		dev_err(&pdev->dev, "Failed to register watchdog device\n");
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static int imx_sc_wdt_remove(struct platform_device *pdev)
> +{
> +	struct watchdog_device *wdt = platform_get_drvdata(pdev);
> +
> +	imx_sc_wdt_stop(wdt);

Any reason for not using watchdog_stop_on_unregister() ?

> +
> +	watchdog_unregister_device(wdt);
> +
> +	return 0;
> +}
> +
> +static void imx_sc_wdt_shutdown(struct platform_device *pdev)
> +{
> +	struct watchdog_device *wdt = platform_get_drvdata(pdev);
> +
> +	if (watchdog_active(wdt))
> +		imx_sc_wdt_stop(wdt);
> +}
> +
Any reason for not using watchdog_stop_on_reboot() ?

> +static const struct of_device_id imx_sc_wdt_dt_ids[] = {
> +	{ .compatible = "fsl,imx8qxp-sc-wdt", },
> +	{ /*sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, imx_sc_wdt_dt_ids);
> +
> +static struct platform_driver imx_sc_wdt_driver = {
> +	.probe		= imx_sc_wdt_probe,
> +	.remove		= imx_sc_wdt_remove,
> +	.shutdown	= imx_sc_wdt_shutdown,
> +	.driver		= {
> +		.name	= "imx-sc-wdt",
> +		.of_match_table = imx_sc_wdt_dt_ids,
> +		.pm	= IMX_SC_WDT_PM_OPS,

I prefer the use of SIMPLE_DEV_PM_OPS() together with
__maybe_unused for the pm functions instead of #ifdef.
This ensures that the unused code compiles even if PM_SLEEP
is not enabled.

Thanks,
Guenter

Re: [PATCH 4/4] arm64: dts: freescale: imx8qxp: add watchdog support

[Shawn Guo]

On Thu, Feb 14, 2019 at 11:45:14AM +0000, Anson Huang wrote:
> Add i.MX8QXP system controller watchdog support.
> 
> Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> ---
> Note: this patch is based on my thermal patch series: https://patchwork.kernel.org/patch/10800699/
> ---
>  arch/arm64/boot/dts/freescale/imx8qxp.dtsi | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/freescale/imx8qxp.dtsi b/arch/arm64/boot/dts/freescale/imx8qxp.dtsi
> index 1bf0e3b..087ba41 100644
> --- a/arch/arm64/boot/dts/freescale/imx8qxp.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8qxp.dtsi
> @@ -155,6 +155,10 @@
>  			tsens-num = <1>;
>  			#thermal-sensor-cells = <1>;
>  		};
> +
> +		wdog: wdog {

watchdog for node name.

Shawn

> +			compatible = "fsl,imx8qxp-sc-wdt";
> +		};
>  	};
>  
>  	timer {
> -- 
> 2.7.4
>