[PATCH v2 0/2] Add drivers for Intel Keem Bay SoC watchdog

[PATCH v2 0/2] Add drivers for Intel Keem Bay SoC watchdog

[vijayakannan.ayyathurai]

From: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>

Hi,

This patch set adds the watchdog timer driver support for Intel Keem Bay Soc.

Patch 1 holds the driver and Patch 2 holds the Device Tree
binding documentation.

This driver was tested on the Keem Bay evaluation module board.

Thank you,
Vijay

Changes since v1:
 - Fix indentation error in the dt-bindings file.
 - Use true/false in the second arg of keembay_wdt_set_timeout_reg().
 - Fix the watchdog start sequence.
 - Avoid reduntant timeout register setting.
 - Remove min usage to find actual time at keembay_wdt_set_timeout().
 - Remove timeout configuration boundary check at
   keembay_wdt_set_pretimeout().
 - Use devm_watchdog_register_device() for wdt registration, which
   eventually supports driver unload functionality as well.

Vijayakannan Ayyathurai (2):
  watchdog: Add watchdog driver for Intel Keembay Soc
  dt-bindings: watchdog: Add bindings for Intel Keem Bay SoC

 .../bindings/watchdog/intel,keembay-wdt.yaml  |  57 ++++
 drivers/watchdog/Kconfig                      |  13 +
 drivers/watchdog/Makefile                     |   1 +
 drivers/watchdog/keembay_wdt.c                | 288 ++++++++++++++++++
 4 files changed, 359 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/intel,keembay-wdt.yaml
 create mode 100644 drivers/watchdog/keembay_wdt.c


base-commit: 3650b228f83adda7e5ee532e2b90429c03f7b9ec
prerequisite-patch-id: 822987dcf4c969ef6ac70359b088af06ba39042b
prerequisite-patch-id: 0a348762b660d0d817b8e70cc71647e83173c78c
prerequisite-patch-id: 54c661a006c7362053cb7602448d6c77419d5cf9
prerequisite-patch-id: d140d8534fb828778e0652fe5fcf6282e027f985
-- 
2.17.1

[PATCH v2 1/2] watchdog: Add watchdog driver for Intel Keembay Soc

[vijayakannan.ayyathurai]

From: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>

Intel Keembay Soc requires watchdog timer support.
Add watchdog driver to enable this.

Signed-off-by: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
Acked-by: Mark Gross <mgross@linux.intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/watchdog/Kconfig       |  13 ++
 drivers/watchdog/Makefile      |   1 +
 drivers/watchdog/keembay_wdt.c | 288 +++++++++++++++++++++++++++++++++
 3 files changed, 302 insertions(+)
 create mode 100644 drivers/watchdog/keembay_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index fd7968635e6d..f412cf2d0f1a 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -2163,4 +2163,17 @@ config USBPCWATCHDOG
 
 	  Most people will say N.
 
+config KEEMBAY_WATCHDOG
+	tristate "Intel Keem Bay SoC non-secure watchdog"
+	depends on ARCH_KEEMBAY || (ARM64 && COMPILE_TEST)
+	select WATCHDOG_CORE
+	help
+	 This option enable support for an In-secure watchdog timer driver for
+	 Intel Keem Bay SoC. This WDT has a 32 bit timer and decrements in every
+	 count unit. An interrupt will be triggered, when the count crosses
+	 the thershold configured in the register.
+
+	 To compile this driver as a module, choose M here: the
+	 module will be called keembay_wdt.
+
 endif # WATCHDOG
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 071a2e50be98..f6f9f434f407 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -146,6 +146,7 @@ obj-$(CONFIG_INTEL_MEI_WDT) += mei_wdt.o
 obj-$(CONFIG_NI903X_WDT) += ni903x_wdt.o
 obj-$(CONFIG_NIC7018_WDT) += nic7018_wdt.o
 obj-$(CONFIG_MLX_WDT) += mlx_wdt.o
+obj-$(CONFIG_KEEMBAY_WATCHDOG) += keembay_wdt.o
 
 # M68K Architecture
 obj-$(CONFIG_M54xx_WATCHDOG) += m54xx_wdt.o
diff --git a/drivers/watchdog/keembay_wdt.c b/drivers/watchdog/keembay_wdt.c
new file mode 100644
index 000000000000..1d08c7f0f16c
--- /dev/null
+++ b/drivers/watchdog/keembay_wdt.c
@@ -0,0 +1,288 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Watchdog driver for Intel Keem Bay non-secure watchdog.
+ *
+ * Copyright (C) 2020 Intel Corporation
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/limits.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/watchdog.h>
+
+/* Non-secure watchdog register offsets */
+#define TIM_WATCHDOG		0x0
+#define TIM_WATCHDOG_INT_THRES	0x4
+#define TIM_WDOG_EN		0x8
+#define TIM_SAFE		0xc
+
+#define WDT_ISR_MASK		GENMASK(9, 8)
+#define WDT_ISR_CLEAR		0x8200ff18
+#define WDT_UNLOCK		0xf1d0dead
+#define WDT_LOAD_MAX		U32_MAX
+#define WDT_LOAD_MIN		1
+#define WDT_TIMEOUT		5
+
+static unsigned int timeout = WDT_TIMEOUT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout period in seconds (default = "
+		 __MODULE_STRING(WDT_TIMEOUT) ")");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = "
+		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+struct keembay_wdt {
+	struct watchdog_device	wdd;
+	struct clk		*clk;
+	unsigned int		rate;
+	int			to_irq;
+	int			th_irq;
+	void __iomem		*base;
+};
+
+static inline u32 keembay_wdt_readl(struct keembay_wdt *wdt, u32 offset)
+{
+	return readl(wdt->base + offset);
+}
+
+static inline void keembay_wdt_writel(struct keembay_wdt *wdt,
+				      u32 offset, u32 val)
+{
+	writel(WDT_UNLOCK, wdt->base + TIM_SAFE);
+	writel(val, wdt->base + offset);
+}
+
+static void keembay_wdt_set_timeout_reg(struct watchdog_device *wdog, bool ping)
+{
+	struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
+	u32 th_val = 0;
+
+	if (ping)
+		keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout * wdt->rate);
+
+	if (!ping && wdog->pretimeout) {
+		th_val = wdog->timeout - wdog->pretimeout;
+		keembay_wdt_writel(wdt, TIM_WATCHDOG_INT_THRES, th_val * wdt->rate);
+	}
+
+	if (!ping)
+		keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout * wdt->rate);
+}
+
+static int keembay_wdt_start(struct watchdog_device *wdog)
+{
+	struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
+
+	keembay_wdt_set_timeout_reg(wdog, false);
+	keembay_wdt_writel(wdt, TIM_WDOG_EN, 1);
+
+	return 0;
+}
+
+static int keembay_wdt_stop(struct watchdog_device *wdog)
+{
+	struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
+
+	keembay_wdt_writel(wdt, TIM_WDOG_EN, 0);
+
+	return 0;
+}
+
+static int keembay_wdt_ping(struct watchdog_device *wdog)
+{
+	keembay_wdt_set_timeout_reg(wdog, true);
+
+	return 0;
+}
+
+static int keembay_wdt_set_timeout(struct watchdog_device *wdog, u32 t)
+{
+	wdog->timeout = t;
+	keembay_wdt_set_timeout_reg(wdog, false);
+
+	return 0;
+}
+
+static int keembay_wdt_set_pretimeout(struct watchdog_device *wdog, u32 t)
+{
+	wdog->pretimeout = t;
+	keembay_wdt_set_timeout_reg(wdog, false);
+
+	return 0;
+}
+
+static unsigned int keembay_wdt_get_timeleft(struct watchdog_device *wdog)
+{
+	struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
+
+	return keembay_wdt_readl(wdt, TIM_WATCHDOG) / wdt->rate;
+}
+
+/*
+ * SMC call is used to clear the interrupt bits, because the TIM_GEN_CONFIG
+ * register is in the secure bank.
+ */
+static irqreturn_t keembay_wdt_to_isr(int irq, void *dev_id)
+{
+	struct keembay_wdt *wdt = dev_id;
+	struct arm_smccc_res res;
+
+	keembay_wdt_writel(wdt, TIM_WATCHDOG, 1);
+	arm_smccc_smc(WDT_ISR_CLEAR, WDT_ISR_MASK, 0, 0, 0, 0, 0, 0, &res);
+	dev_crit(wdt->wdd.parent, "Intel Keem Bay non-sec wdt timeout.\n");
+	emergency_restart();
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t keembay_wdt_th_isr(int irq, void *dev_id)
+{
+	struct keembay_wdt *wdt = dev_id;
+	struct arm_smccc_res res;
+	u32 th_val = 0;
+
+	if (wdt->wdd.pretimeout)
+		th_val = wdt->wdd.timeout - wdt->wdd.pretimeout;
+
+	keembay_wdt_writel(wdt, TIM_WATCHDOG, th_val * wdt->rate + 1);
+	arm_smccc_smc(WDT_ISR_CLEAR, WDT_ISR_MASK, 0, 0, 0, 0, 0, 0, &res);
+	dev_crit(wdt->wdd.parent, "Intel Keem Bay non-sec wdt pre-timeout.\n");
+	watchdog_notify_pretimeout(&wdt->wdd);
+
+	return IRQ_HANDLED;
+}
+
+static const struct watchdog_info keembay_wdt_info = {
+	.identity	= "Intel Keem Bay Watchdog Timer",
+	.options	= WDIOF_SETTIMEOUT |
+			  WDIOF_PRETIMEOUT |
+			  WDIOF_MAGICCLOSE |
+			  WDIOF_KEEPALIVEPING,
+};
+
+static const struct watchdog_ops keembay_wdt_ops = {
+	.owner		= THIS_MODULE,
+	.start		= keembay_wdt_start,
+	.stop		= keembay_wdt_stop,
+	.ping		= keembay_wdt_ping,
+	.set_timeout	= keembay_wdt_set_timeout,
+	.set_pretimeout	= keembay_wdt_set_pretimeout,
+	.get_timeleft	= keembay_wdt_get_timeleft,
+};
+
+static int keembay_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct keembay_wdt *wdt;
+	int ret;
+
+	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	wdt->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(wdt->base))
+		return PTR_ERR(wdt->base);
+
+	/* we do not need to enable the clock as it is enabled by default */
+	wdt->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(wdt->clk))
+		return dev_err_probe(dev, PTR_ERR(wdt->clk), "Failed to get clock\n");
+
+	wdt->rate = clk_get_rate(wdt->clk);
+	if (!wdt->rate)
+		return dev_err_probe(dev, -EINVAL, "Failed to get clock rate\n");
+
+	wdt->th_irq = platform_get_irq_byname(pdev, "threshold");
+	if (wdt->th_irq < 0)
+		return dev_err_probe(dev, wdt->th_irq, "Failed to get IRQ for threshold\n");
+
+	ret = devm_request_irq(dev, wdt->th_irq, keembay_wdt_th_isr, 0,
+			       "keembay-wdt", wdt);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to request IRQ for threshold\n");
+
+	wdt->to_irq = platform_get_irq_byname(pdev, "timeout");
+	if (wdt->to_irq < 0)
+		return dev_err_probe(dev, wdt->to_irq, "Failed to get IRQ for timeout\n");
+
+	ret = devm_request_irq(dev, wdt->to_irq, keembay_wdt_to_isr, 0,
+			       "keembay-wdt", wdt);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to request IRQ for timeout\n");
+
+	wdt->wdd.parent		= dev;
+	wdt->wdd.info		= &keembay_wdt_info;
+	wdt->wdd.ops		= &keembay_wdt_ops;
+	wdt->wdd.min_timeout	= WDT_LOAD_MIN;
+	wdt->wdd.max_timeout	= WDT_LOAD_MAX / wdt->rate;
+	wdt->wdd.timeout	= WDT_TIMEOUT;
+
+	watchdog_set_drvdata(&wdt->wdd, wdt);
+	watchdog_set_nowayout(&wdt->wdd, nowayout);
+	watchdog_init_timeout(&wdt->wdd, timeout, dev);
+	keembay_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout);
+
+	ret = devm_watchdog_register_device(dev, &wdt->wdd);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register watchdog device.\n");
+
+	platform_set_drvdata(pdev, wdt);
+	dev_info(dev, "Initial timeout %d sec%s.\n",
+		 wdt->wdd.timeout, nowayout ? ", nowayout" : "");
+
+	return 0;
+}
+
+static int __maybe_unused keembay_wdt_suspend(struct device *dev)
+{
+	struct keembay_wdt *wdt = dev_get_drvdata(dev);
+
+	if (watchdog_active(&wdt->wdd))
+		return keembay_wdt_stop(&wdt->wdd);
+
+	return 0;
+}
+
+static int __maybe_unused keembay_wdt_resume(struct device *dev)
+{
+	struct keembay_wdt *wdt = dev_get_drvdata(dev);
+
+	if (watchdog_active(&wdt->wdd))
+		return keembay_wdt_start(&wdt->wdd);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(keembay_wdt_pm_ops, keembay_wdt_suspend,
+			 keembay_wdt_resume);
+
+static const struct of_device_id keembay_wdt_match[] = {
+	{ .compatible = "intel,keembay-wdt" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, keembay_wdt_match);
+
+static struct platform_driver keembay_wdt_driver = {
+	.probe		= keembay_wdt_probe,
+	.driver		= {
+		.name		= "keembay_wdt",
+		.of_match_table	= keembay_wdt_match,
+		.pm		= &keembay_wdt_pm_ops,
+	},
+};
+
+module_platform_driver(keembay_wdt_driver);
+
+MODULE_DESCRIPTION("Intel Keem Bay SoC watchdog driver");
+MODULE_AUTHOR("Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com");
+MODULE_LICENSE("GPL v2");
-- 
2.17.1

[PATCH v2 2/2] dt-bindings: watchdog: Add bindings for Intel Keem Bay SoC

[vijayakannan.ayyathurai]

From: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>

Add Device Tree binding document for Watchdog IP in the Intel Keem Bay SoC.

Signed-off-by: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
Acked-by: Mark Gross <mgross@linux.intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 .../bindings/watchdog/intel,keembay-wdt.yaml  | 57 +++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/intel,keembay-wdt.yaml

diff --git a/Documentation/devicetree/bindings/watchdog/intel,keembay-wdt.yaml b/Documentation/devicetree/bindings/watchdog/intel,keembay-wdt.yaml
new file mode 100644
index 000000000000..1437ff8a122f
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/intel,keembay-wdt.yaml
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/watchdog/intel,keembay-wdt.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Intel Keem Bay SoC non-secure Watchdog Timer
+
+maintainers:
+  - Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>
+
+properties:
+  compatible:
+    enum:
+      - intel,keembay-wdt
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  interrupts:
+    items:
+      - description: interrupt specifier for threshold interrupt line
+      - description: interrupt specifier for timeout interrupt line
+
+  interrupt-names:
+    items:
+      - const: threshold
+      - const: timeout
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-names
+  - clocks
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #define KEEM_BAY_A53_TIM
+
+    watchdog: watchdog@2033009c {
+        compatible = "intel,keembay-wdt";
+        reg = <0x2033009c 0x10>;
+        interrupts = <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 2 IRQ_TYPE_LEVEL_HIGH>;
+        interrupt-names = "threshold", "timeout";
+        clocks = <&scmi_clk KEEM_BAY_A53_TIM>;
+    };
+
+...
-- 
2.17.1

Re: [PATCH v2 0/2] Add drivers for Intel Keem Bay SoC watchdog

[mark gross]

On Wed, Nov 11, 2020 at 01:53:06AM +0800, vijayakannan.ayyathurai@intel.com wrote:
> From: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
> 
> Hi,
> 
> This patch set adds the watchdog timer driver support for Intel Keem Bay Soc.
> 
> Patch 1 holds the driver and Patch 2 holds the Device Tree
> binding documentation.
> 
> This driver was tested on the Keem Bay evaluation module board.
> 
> Thank you,
> Vijay
> 
> Changes since v1:
>  - Fix indentation error in the dt-bindings file.
>  - Use true/false in the second arg of keembay_wdt_set_timeout_reg().
>  - Fix the watchdog start sequence.
>  - Avoid reduntant timeout register setting.
>  - Remove min usage to find actual time at keembay_wdt_set_timeout().
>  - Remove timeout configuration boundary check at
>    keembay_wdt_set_pretimeout().
>  - Use devm_watchdog_register_device() for wdt registration, which
>    eventually supports driver unload functionality as well.
> 
> Vijayakannan Ayyathurai (2):
>   watchdog: Add watchdog driver for Intel Keembay Soc
>   dt-bindings: watchdog: Add bindings for Intel Keem Bay SoC
> 
>  .../bindings/watchdog/intel,keembay-wdt.yaml  |  57 ++++
>  drivers/watchdog/Kconfig                      |  13 +
>  drivers/watchdog/Makefile                     |   1 +
>  drivers/watchdog/keembay_wdt.c                | 288 ++++++++++++++++++
>  4 files changed, 359 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/watchdog/intel,keembay-wdt.yaml
>  create mode 100644 drivers/watchdog/keembay_wdt.c
> 
> 
> base-commit: 3650b228f83adda7e5ee532e2b90429c03f7b9ec
> prerequisite-patch-id: 822987dcf4c969ef6ac70359b088af06ba39042b
> prerequisite-patch-id: 0a348762b660d0d817b8e70cc71647e83173c78c
> prerequisite-patch-id: 54c661a006c7362053cb7602448d6c77419d5cf9
> prerequisite-patch-id: d140d8534fb828778e0652fe5fcf6282e027f985
these patch-id's are not helpful to me if I want to to a test build of this
patch.  Those SHA1's are not available to others unless there is a public
non-rebasing tree I can pull from.  if there is one then you should provide the
git remot URL for that otherwise I cannot fetch those prerequisites.

Maybe it would be better to list the mailing list archive URL for each change
instead.

--mark

> -- 
> 2.17.1
> 

Re: [PATCH v2 2/2] dt-bindings: watchdog: Add bindings for Intel Keem Bay SoC

[Rob Herring]

On Wed, 11 Nov 2020 01:53:08 +0800, vijayakannan.ayyathurai@intel.com wrote:
> From: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
> 
> Add Device Tree binding document for Watchdog IP in the Intel Keem Bay SoC.
> 
> Signed-off-by: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
> Acked-by: Mark Gross <mgross@linux.intel.com>
> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  .../bindings/watchdog/intel,keembay-wdt.yaml  | 57 +++++++++++++++++++
>  1 file changed, 57 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/watchdog/intel,keembay-wdt.yaml
> 

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

RE: [PATCH v2 2/2] dt-bindings: watchdog: Add bindings for Intel Keem Bay SoC

[Ayyathurai, Vijayakannan]

Hi Rob,
Thanks for reviewing this patch.

> From: Rob Herring <robh@kernel.org>
> Sent: Thursday, 12 November, 2020 4:04 AM
> Subject: Re: [PATCH v2 2/2] dt-bindings: watchdog: Add bindings for Intel
> Keem Bay SoC
> 
> On Wed, 11 Nov 2020 01:53:08 +0800, vijayakannan.ayyathurai@intel.com
> wrote:
> > From: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
> >
> > Add Device Tree binding document for Watchdog IP in the Intel Keem Bay
> SoC.
> >
> > Signed-off-by: Vijayakannan Ayyathurai
> <vijayakannan.ayyathurai@intel.com>
> > Acked-by: Mark Gross <mgross@linux.intel.com>
> > Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > ---
> >  .../bindings/watchdog/intel,keembay-wdt.yaml  | 57 +++++++++++++++++++
> >  1 file changed, 57 insertions(+)
> >  create mode 100644
> Documentation/devicetree/bindings/watchdog/intel,keembay-wdt.yaml
> >
> 
> Reviewed-by: Rob Herring <robh@kernel.org>

Thanks,
Vijay

RE: [PATCH v2 0/2] Add drivers for Intel Keem Bay SoC watchdog

[Ayyathurai, Vijayakannan]

Hi,

> From: Ayyathurai, Vijayakannan <vijayakannan.ayyathurai@intel.com>
> Sent: Wednesday, 11 November, 2020 1:53 AM
> Subject: [PATCH v2 0/2] Add drivers for Intel Keem Bay SoC watchdog
> 
> From: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
> 
> Hi,
> 
> This patch set adds the watchdog timer driver support for Intel Keem Bay Soc.
> 
> Patch 1 holds the driver and Patch 2 holds the Device Tree
> binding documentation.
> 
> This driver was tested on the Keem Bay evaluation module board.
> 
> Thank you,
> Vijay
> 
> Changes since v1:
>  - Fix indentation error in the dt-bindings file.
>  - Use true/false in the second arg of keembay_wdt_set_timeout_reg().
>  - Fix the watchdog start sequence.
>  - Avoid reduntant timeout register setting.
>  - Remove min usage to find actual time at keembay_wdt_set_timeout().
>  - Remove timeout configuration boundary check at
>    keembay_wdt_set_pretimeout().
>  - Use devm_watchdog_register_device() for wdt registration, which
>    eventually supports driver unload functionality as well.
> 

Please consider review this patch and let me know 
if there is further feedback.

> Vijayakannan Ayyathurai (2):
>   watchdog: Add watchdog driver for Intel Keembay Soc
>   dt-bindings: watchdog: Add bindings for Intel Keem Bay SoC
> 
>  .../bindings/watchdog/intel,keembay-wdt.yaml  |  57 ++++
>  drivers/watchdog/Kconfig                      |  13 +
>  drivers/watchdog/Makefile                     |   1 +
>  drivers/watchdog/keembay_wdt.c                | 288 ++++++++++++++++++
>  4 files changed, 359 insertions(+)
>  create mode 100644
> Documentation/devicetree/bindings/watchdog/intel,keembay-wdt.yaml
>  create mode 100644 drivers/watchdog/keembay_wdt.c
> 
> 
> base-commit: 3650b228f83adda7e5ee532e2b90429c03f7b9ec
> --
> 2.17.1

Thanks,
Vijay

Re: [PATCH v2 1/2] watchdog: Add watchdog driver for Intel Keembay Soc

[Guenter Roeck]

On Wed, Nov 11, 2020 at 01:53:07AM +0800, vijayakannan.ayyathurai@intel.com wrote:
> From: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
> 
> Intel Keembay Soc requires watchdog timer support.
> Add watchdog driver to enable this.
> 
> Signed-off-by: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
> Acked-by: Mark Gross <mgross@linux.intel.com>
> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/watchdog/Kconfig       |  13 ++
>  drivers/watchdog/Makefile      |   1 +
>  drivers/watchdog/keembay_wdt.c | 288 +++++++++++++++++++++++++++++++++
>  3 files changed, 302 insertions(+)
>  create mode 100644 drivers/watchdog/keembay_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index fd7968635e6d..f412cf2d0f1a 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -2163,4 +2163,17 @@ config USBPCWATCHDOG
>  
>  	  Most people will say N.
>  
> +config KEEMBAY_WATCHDOG
> +	tristate "Intel Keem Bay SoC non-secure watchdog"
> +	depends on ARCH_KEEMBAY || (ARM64 && COMPILE_TEST)
> +	select WATCHDOG_CORE
> +	help
> +	 This option enable support for an In-secure watchdog timer driver for
> +	 Intel Keem Bay SoC. This WDT has a 32 bit timer and decrements in every
> +	 count unit. An interrupt will be triggered, when the count crosses
> +	 the thershold configured in the register.
> +
> +	 To compile this driver as a module, choose M here: the
> +	 module will be called keembay_wdt.
> +
>  endif # WATCHDOG
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 071a2e50be98..f6f9f434f407 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -146,6 +146,7 @@ obj-$(CONFIG_INTEL_MEI_WDT) += mei_wdt.o
>  obj-$(CONFIG_NI903X_WDT) += ni903x_wdt.o
>  obj-$(CONFIG_NIC7018_WDT) += nic7018_wdt.o
>  obj-$(CONFIG_MLX_WDT) += mlx_wdt.o
> +obj-$(CONFIG_KEEMBAY_WATCHDOG) += keembay_wdt.o
>  
>  # M68K Architecture
>  obj-$(CONFIG_M54xx_WATCHDOG) += m54xx_wdt.o
> diff --git a/drivers/watchdog/keembay_wdt.c b/drivers/watchdog/keembay_wdt.c
> new file mode 100644
> index 000000000000..1d08c7f0f16c
> --- /dev/null
> +++ b/drivers/watchdog/keembay_wdt.c
> @@ -0,0 +1,288 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Watchdog driver for Intel Keem Bay non-secure watchdog.
> + *
> + * Copyright (C) 2020 Intel Corporation
> + */
> +
> +#include <linux/arm-smccc.h>
> +#include <linux/bits.h>
> +#include <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/limits.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/platform_device.h>
> +#include <linux/reboot.h>
> +#include <linux/watchdog.h>
> +
> +/* Non-secure watchdog register offsets */
> +#define TIM_WATCHDOG		0x0
> +#define TIM_WATCHDOG_INT_THRES	0x4
> +#define TIM_WDOG_EN		0x8
> +#define TIM_SAFE		0xc
> +
> +#define WDT_ISR_MASK		GENMASK(9, 8)
> +#define WDT_ISR_CLEAR		0x8200ff18
> +#define WDT_UNLOCK		0xf1d0dead
> +#define WDT_LOAD_MAX		U32_MAX
> +#define WDT_LOAD_MIN		1
> +#define WDT_TIMEOUT		5
> +
> +static unsigned int timeout = WDT_TIMEOUT;
> +module_param(timeout, int, 0);
> +MODULE_PARM_DESC(timeout, "Watchdog timeout period in seconds (default = "
> +		 __MODULE_STRING(WDT_TIMEOUT) ")");
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, bool, 0);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = "
> +		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +
> +struct keembay_wdt {
> +	struct watchdog_device	wdd;
> +	struct clk		*clk;
> +	unsigned int		rate;
> +	int			to_irq;
> +	int			th_irq;
> +	void __iomem		*base;
> +};
> +
> +static inline u32 keembay_wdt_readl(struct keembay_wdt *wdt, u32 offset)
> +{
> +	return readl(wdt->base + offset);
> +}
> +
> +static inline void keembay_wdt_writel(struct keembay_wdt *wdt,
> +				      u32 offset, u32 val)
> +{
> +	writel(WDT_UNLOCK, wdt->base + TIM_SAFE);
> +	writel(val, wdt->base + offset);
> +}
> +
> +static void keembay_wdt_set_timeout_reg(struct watchdog_device *wdog, bool ping)
> +{
> +	struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
> +	u32 th_val = 0;
> +
> +	if (ping)
> +		keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout * wdt->rate);
> +
> +	if (!ping && wdog->pretimeout) {
> +		th_val = wdog->timeout - wdog->pretimeout;
> +		keembay_wdt_writel(wdt, TIM_WATCHDOG_INT_THRES, th_val * wdt->rate);
> +	}
> +
> +	if (!ping)
> +		keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout * wdt->rate);

I am a bit at loss here. This seems unnecessarily complex. Why not just the following ?

	if (!ping && wdog->pretimeout) {
		th_val = wdog->timeout - wdog->pretimeout;
		keembay_wdt_writel(wdt, TIM_WATCHDOG_INT_THRES, th_val * wdt->rate);
	}
	keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout * wdt->rate);

Thanks,
Guenter

RE: [PATCH v2 1/2] watchdog: Add watchdog driver for Intel Keembay Soc

[Ayyathurai, Vijayakannan]

Hi Guenter,

> From: Guenter Roeck <linux@roeck-us.net>
> 
> On Wed, Nov 11, 2020 at 01:53:07AM +0800,
> vijayakannan.ayyathurai@intel.com wrote:
> > From: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
> >
> > Intel Keembay Soc requires watchdog timer support.
> > Add watchdog driver to enable this.
> >
> > +static void keembay_wdt_set_timeout_reg(struct watchdog_device *wdog,
> bool ping)
> > +{
> > +	struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
> > +	u32 th_val = 0;
> > +
> > +	if (ping)
> > +		keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout *
> wdt->rate);
> > +
> > +	if (!ping && wdog->pretimeout) {
> > +		th_val = wdog->timeout - wdog->pretimeout;
> > +		keembay_wdt_writel(wdt, TIM_WATCHDOG_INT_THRES, th_val
> * wdt->rate);
> > +	}
> > +
> > +	if (!ping)
> > +		keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout *
> wdt->rate);
> 
> I am a bit at loss here. This seems unnecessarily complex. Why not just the
> following ?
> 

Sure. I can follow the below way.
Let me know if there is further comments to improve for the next version.

> 	if (!ping && wdog->pretimeout) {
> 		th_val = wdog->timeout - wdog->pretimeout;
> 		keembay_wdt_writel(wdt, TIM_WATCHDOG_INT_THRES, th_val
> * wdt->rate);
> 	}
> 	keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout * wdt-
> >rate);
> 
> Thanks,
> Guenter

Thanks,
Vijay

Re: [PATCH v2 1/2] watchdog: Add watchdog driver for Intel Keembay Soc

[Guenter Roeck]

On Tue, Dec 01, 2020 at 06:19:09AM +0000, Ayyathurai, Vijayakannan wrote:
> Hi Guenter,
> 
> > From: Guenter Roeck <linux@roeck-us.net>
> > 
> > On Wed, Nov 11, 2020 at 01:53:07AM +0800,
> > vijayakannan.ayyathurai@intel.com wrote:
> > > From: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
> > >
> > > Intel Keembay Soc requires watchdog timer support.
> > > Add watchdog driver to enable this.
> > >
> > > +static void keembay_wdt_set_timeout_reg(struct watchdog_device *wdog,
> > bool ping)
> > > +{
> > > +	struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
> > > +	u32 th_val = 0;
> > > +
> > > +	if (ping)
> > > +		keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout *
> > wdt->rate);
> > > +
> > > +	if (!ping && wdog->pretimeout) {
> > > +		th_val = wdog->timeout - wdog->pretimeout;
> > > +		keembay_wdt_writel(wdt, TIM_WATCHDOG_INT_THRES, th_val
> > * wdt->rate);
> > > +	}
> > > +
> > > +	if (!ping)
> > > +		keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout *
> > wdt->rate);
> > 
> > I am a bit at loss here. This seems unnecessarily complex. Why not just the
> > following ?
> > 
> 
> Sure. I can follow the below way.
> Let me know if there is further comments to improve for the next version.
> 
No, that was all. Driver looks good otherwise.

Guenter

> > 	if (!ping && wdog->pretimeout) {
> > 		th_val = wdog->timeout - wdog->pretimeout;
> > 		keembay_wdt_writel(wdt, TIM_WATCHDOG_INT_THRES, th_val
> > * wdt->rate);
> > 	}
> > 	keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout * wdt-
> > >rate);
> > 
> > Thanks,
> > Guenter
> 
> Thanks,
> Vijay