[PATCHv2 0/4] watchdog: add TI K3 SoC watchdog support

[PATCHv2 0/4] watchdog: add TI K3 SoC watchdog support

[Tero Kristo]

Hi,

Changes from v1:

- Apply the last_hw_keepalive time fix always when starting a watchdog
- Only query fck rate during probe, not during runtime
- Add better documentation of HW limitations for RTI watchdog under
  driver code
- Drop unnecessary WARN_ON

-Tero


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[PATCHv2 1/4] dt-bindings: watchdog: Add support for TI K3 RTI watchdog

[Tero Kristo]

TI K3 SoCs contain an RTI (Real Time Interrupt) module which can be
used to implement a windowed watchdog functionality. Windowed watchdog
will generate an error if it is petted outside the time window, either
too early or too late.

Cc: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Tero Kristo <t-kristo@ti.com>
---
 .../bindings/watchdog/ti,rti-wdt.yaml         | 52 +++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml

diff --git a/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml b/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
new file mode 100644
index 000000000000..3813f59fb6c3
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/watchdog/ti,rti-wdt.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments K3 SoC Watchdog Timer
+
+maintainers:
+  - Tero Kristo <t-kristo@ti.com>
+
+description: |+
+  The TI K3 SoC watchdog timer is implemented via the RTI (Real Time
+  Interrupt) IP module. This timer adds a support for windowed watchdog
+  mode, which will signal an error if it is pinged outside the watchdog
+  time window, meaning either too early or too late. The error signal
+  generated can be routed to either interrupt a safety controller or
+  to directly reset the SoC.
+
+properties:
+  compatible:
+    enum:
+      - ti,rti-wdt
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+
+examples:
+  - |
+    /*
+     * RTI WDT in main domain on J721e SoC. Assigned clocks are used to
+     * select the source clock for the watchdog, forcing it to tick with
+     * a 32kHz clock in this case.
+     */
+    #include <dt-bindings/soc/ti,sci_pm_domain.h>
+
+    main_rti0: rti@2200000 {
+        compatible = "ti,rti-wdt";
+        reg = <0x0 0x2200000 0x0 0x100>;
+        clocks = <&k3_clks 252 1>;
+        power-domains = <&k3_pds 252 TI_SCI_PD_EXCLUSIVE>;
+        assigned-clocks = <&k3_clks 252 1>;
+        assigned-clock-parents = <&k3_clks 252 5>;
+    };
-- 
2.17.1

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Re: [PATCHv2 1/4] dt-bindings: watchdog: Add support for TI K3 RTI watchdog

[Rob Herring]

On Mon, Mar 02, 2020 at 10:04:23PM +0200, Tero Kristo wrote:
> TI K3 SoCs contain an RTI (Real Time Interrupt) module which can be
> used to implement a windowed watchdog functionality. Windowed watchdog
> will generate an error if it is petted outside the time window, either
> too early or too late.
> 
> Cc: Rob Herring <robh@kernel.org>
> Cc: devicetree@vger.kernel.org
> Signed-off-by: Tero Kristo <t-kristo@ti.com>
> ---
>  .../bindings/watchdog/ti,rti-wdt.yaml         | 52 +++++++++++++++++++
>  1 file changed, 52 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml b/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
> new file mode 100644
> index 000000000000..3813f59fb6c3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
> @@ -0,0 +1,52 @@
> +# SPDX-License-Identifier: GPL-2.0

Dual license new bindings please:

(GPL-2.0-only OR BSD-2-Clause)

> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/watchdog/ti,rti-wdt.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Texas Instruments K3 SoC Watchdog Timer
> +
> +maintainers:
> +  - Tero Kristo <t-kristo@ti.com>
> +
> +description: |+

You can drop '|+' as there's no formatting to preserve.

> +  The TI K3 SoC watchdog timer is implemented via the RTI (Real Time
> +  Interrupt) IP module. This timer adds a support for windowed watchdog
> +  mode, which will signal an error if it is pinged outside the watchdog
> +  time window, meaning either too early or too late. The error signal
> +  generated can be routed to either interrupt a safety controller or
> +  to directly reset the SoC.
> +

Reference the common watchdog.yaml schema.

> +properties:
> +  compatible:
> +    enum:
> +      - ti,rti-wdt

Should be SoC specific possibly with a fallback.

> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +
> +examples:
> +  - |
> +    /*
> +     * RTI WDT in main domain on J721e SoC. Assigned clocks are used to
> +     * select the source clock for the watchdog, forcing it to tick with
> +     * a 32kHz clock in this case.
> +     */
> +    #include <dt-bindings/soc/ti,sci_pm_domain.h>
> +
> +    main_rti0: rti@2200000 {

watchdog@...

> +        compatible = "ti,rti-wdt";
> +        reg = <0x0 0x2200000 0x0 0x100>;
> +        clocks = <&k3_clks 252 1>;
> +        power-domains = <&k3_pds 252 TI_SCI_PD_EXCLUSIVE>;

Not documented.

> +        assigned-clocks = <&k3_clks 252 1>;
> +        assigned-clock-parents = <&k3_clks 252 5>;

Not documented.

> +    };
> -- 
> 2.17.1
> 
> --
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

Re: [PATCHv2 1/4] dt-bindings: watchdog: Add support for TI K3 RTI watchdog

[Tero Kristo]

On 10/03/2020 21:37, Rob Herring wrote:
> On Mon, Mar 02, 2020 at 10:04:23PM +0200, Tero Kristo wrote:
>> TI K3 SoCs contain an RTI (Real Time Interrupt) module which can be
>> used to implement a windowed watchdog functionality. Windowed watchdog
>> will generate an error if it is petted outside the time window, either
>> too early or too late.
>>
>> Cc: Rob Herring <robh@kernel.org>
>> Cc: devicetree@vger.kernel.org
>> Signed-off-by: Tero Kristo <t-kristo@ti.com>
>> ---
>>   .../bindings/watchdog/ti,rti-wdt.yaml         | 52 +++++++++++++++++++
>>   1 file changed, 52 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml b/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
>> new file mode 100644
>> index 000000000000..3813f59fb6c3
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
>> @@ -0,0 +1,52 @@
>> +# SPDX-License-Identifier: GPL-2.0
> 
> Dual license new bindings please:
> 
> (GPL-2.0-only OR BSD-2-Clause)

Ok, will fix this.

> 
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/watchdog/ti,rti-wdt.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Texas Instruments K3 SoC Watchdog Timer
>> +
>> +maintainers:
>> +  - Tero Kristo <t-kristo@ti.com>
>> +
>> +description: |+
> 
> You can drop '|+' as there's no formatting to preserve.

Ok.

> 
>> +  The TI K3 SoC watchdog timer is implemented via the RTI (Real Time
>> +  Interrupt) IP module. This timer adds a support for windowed watchdog
>> +  mode, which will signal an error if it is pinged outside the watchdog
>> +  time window, meaning either too early or too late. The error signal
>> +  generated can be routed to either interrupt a safety controller or
>> +  to directly reset the SoC.
>> +
> 
> Reference the common watchdog.yaml schema.

I believe you mean just adding:

allOf:
   - $ref: "watchdog.yaml#"


> 
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - ti,rti-wdt
> 
> Should be SoC specific possibly with a fallback.

Ok, will change this.

> 
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  clocks:
>> +    maxItems: 1
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - clocks
>> +
>> +examples:
>> +  - |
>> +    /*
>> +     * RTI WDT in main domain on J721e SoC. Assigned clocks are used to
>> +     * select the source clock for the watchdog, forcing it to tick with
>> +     * a 32kHz clock in this case.
>> +     */
>> +    #include <dt-bindings/soc/ti,sci_pm_domain.h>
>> +
>> +    main_rti0: rti@2200000 {
> 
> watchdog@...

Right.

> 
>> +        compatible = "ti,rti-wdt";
>> +        reg = <0x0 0x2200000 0x0 0x100>;
>> +        clocks = <&k3_clks 252 1>;
>> +        power-domains = <&k3_pds 252 TI_SCI_PD_EXCLUSIVE>;
> 
> Not documented.

For this and assigned-clocks below...

> 
>> +        assigned-clocks = <&k3_clks 252 1>;
>> +        assigned-clock-parents = <&k3_clks 252 5>;
> 
> Not documented.

Ok will fix these, I was grepping for examples under the yaml files and 
some seem to document these standard props, some not. But, I guess 
everything listed in the examples should be documented.

Sorry all this yaml stuff is still pretty new to me. >.<

-Tero

> 
>> +    };
>> -- 
>> 2.17.1
>>
>> --

--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

[PATCHv2 2/4] watchdog: reset last_hw_keepalive time at start

[Tero Kristo]

Currently the watchdog core does not initialize the last_hw_keepalive
time during watchdog startup. This will cause the watchdog to be pinged
immediately if enough time has passed from the system boot-up time, and
some types of watchdogs like K3 RTI does not like this.

To avoid the issue, setup the last_hw_keepalive time during watchdog
startup.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
---
v2:
  * apply functionality always instead of being behind a flag

 drivers/watchdog/watchdog_dev.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 8b5c742f24e8..7e4cd34a8c20 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -282,6 +282,7 @@ static int watchdog_start(struct watchdog_device *wdd)
 	if (err == 0) {
 		set_bit(WDOG_ACTIVE, &wdd->status);
 		wd_data->last_keepalive = started_at;
+		wd_data->last_hw_keepalive = started_at;
 		watchdog_update_worker(wdd);
 	}
 
-- 
2.17.1

--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

Re: [PATCHv2 2/4] watchdog: reset last_hw_keepalive time at start

[Guenter Roeck]

On Mon, Mar 02, 2020 at 10:04:24PM +0200, Tero Kristo wrote:
> Currently the watchdog core does not initialize the last_hw_keepalive
> time during watchdog startup. This will cause the watchdog to be pinged
> immediately if enough time has passed from the system boot-up time, and
> some types of watchdogs like K3 RTI does not like this.
> 
> To avoid the issue, setup the last_hw_keepalive time during watchdog
> startup.
> 
> Signed-off-by: Tero Kristo <t-kristo@ti.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
> v2:
>   * apply functionality always instead of being behind a flag
> 
>  drivers/watchdog/watchdog_dev.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
> index 8b5c742f24e8..7e4cd34a8c20 100644
> --- a/drivers/watchdog/watchdog_dev.c
> +++ b/drivers/watchdog/watchdog_dev.c
> @@ -282,6 +282,7 @@ static int watchdog_start(struct watchdog_device *wdd)
>  	if (err == 0) {
>  		set_bit(WDOG_ACTIVE, &wdd->status);
>  		wd_data->last_keepalive = started_at;
> +		wd_data->last_hw_keepalive = started_at;
>  		watchdog_update_worker(wdd);
>  	}
>  
> -- 
> 2.17.1
> 
> --
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

[PATCHv2 3/4] watchdog: Add K3 RTI watchdog support

[Tero Kristo]

Texas Instruments K3 SoCs contain an RTI (Real Time Interrupt) module
which can be used as a watchdog. This IP provides a support for
windowed watchdog mode, in which the watchdog must be petted within
a certain time window. If it is petted either too soon, or too late,
a watchdog error will be triggered.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
---
v2:
  * Added better documentation within the driver code
  * Dropped fck handle, instead get the fck rate during probe only
  * Modified the max_hw_heartbeat calculation logic a bit

 drivers/watchdog/Kconfig   |   8 ++
 drivers/watchdog/Makefile  |   1 +
 drivers/watchdog/rti_wdt.c | 254 +++++++++++++++++++++++++++++++++++++
 3 files changed, 261 insertions(+)
 create mode 100644 drivers/watchdog/rti_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index cec868f8db3f..81faf47d44a6 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -583,6 +583,14 @@ config DAVINCI_WATCHDOG
 	  NOTE: once enabled, this timer cannot be disabled.
 	  Say N if you are unsure.
 
+config K3_RTI_WATCHDOG
+	tristate "Texas Instruments K3 RTI watchdog"
+	depends on ARCH_K3 || COMPILE_TEST
+	select WATCHDOG_CORE
+	help
+	  Say Y here if you want to include support for the K3 watchdog
+	  timer (RTI module) available in the K3 generation of processors.
+
 config ORION_WATCHDOG
 	tristate "Orion watchdog"
 	depends on ARCH_ORION5X || ARCH_DOVE || MACH_DOVE || ARCH_MVEBU || (COMPILE_TEST && !ARCH_EBSA110)
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 2ee352bf3372..6de2e4ceef19 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -57,6 +57,7 @@ obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
 obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
 obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
 obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
+obj-$(CONFIG_K3_RTI_WATCHDOG) += rti_wdt.o
 obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
 obj-$(CONFIG_SUNXI_WATCHDOG) += sunxi_wdt.o
 obj-$(CONFIG_RN5T618_WATCHDOG) += rn5t618_wdt.o
diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
new file mode 100644
index 000000000000..7a46c40891e2
--- /dev/null
+++ b/drivers/watchdog/rti_wdt.c
@@ -0,0 +1,254 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Watchdog driver for the K3 RTI module
+ *
+ * (c) Copyright 2019-2020 Texas Instruments Inc.
+ * All rights reserved.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+#define DEFAULT_HEARTBEAT 60
+
+/* Max heartbeat is calculated at 32kHz source clock */
+#define MAX_HEARTBEAT	1000
+
+/* Timer register set definition */
+#define RTIDWDCTRL	0x90
+#define RTIDWDPRLD	0x94
+#define RTIWDSTATUS	0x98
+#define RTIWDKEY	0x9c
+#define RTIDWDCNTR	0xa0
+#define RTIWWDRXCTRL	0xa4
+#define RTIWWDSIZECTRL	0xa8
+
+#define RTIWWDRX_NMI	0xa
+
+#define RTIWWDSIZE_50P	0x50
+
+#define WDENABLE_KEY	0xa98559da
+
+#define WDKEY_SEQ0		0xe51a
+#define WDKEY_SEQ1		0xa35c
+
+#define WDT_PRELOAD_SHIFT	13
+
+#define WDT_PRELOAD_MAX		0xfff
+
+#define DWDST			BIT(1)
+
+static int heartbeat;
+
+/*
+ * struct to hold data for each WDT device
+ * @base - base io address of WD device
+ * @freq - source clock frequency of WDT
+ * @wdd  - hold watchdog device as is in WDT core
+ */
+struct rti_wdt_device {
+	void __iomem		*base;
+	unsigned long		freq;
+	struct watchdog_device	wdd;
+};
+
+static int rti_wdt_start(struct watchdog_device *wdd)
+{
+	u32 timer_margin;
+	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
+
+	/* set timeout period */
+	timer_margin = (u64)wdd->timeout * wdt->freq;
+	timer_margin >>= WDT_PRELOAD_SHIFT;
+	if (timer_margin > WDT_PRELOAD_MAX)
+		timer_margin = WDT_PRELOAD_MAX;
+	writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
+
+	/*
+	 * RTI only supports a windowed mode, where the watchdog can only
+	 * be petted during the open window; not too early or not too late.
+	 * The HW configuration options only allow for the open window size
+	 * to be 50% or less than that; we obviouly want to configure the open
+	 * window as large as possible so we select the 50% option. To avoid
+	 * any glitches, we accommodate 5% safety margin also, so we setup
+	 * the min_hw_hearbeat at 55% of the timeout period.
+	 */
+	wdd->min_hw_heartbeat_ms = 11 * wdd->timeout * 1000 / 20;
+
+	/* Generate NMI when wdt expires */
+	writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
+
+	/* Open window size 50%; this is the largest window size available */
+	writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
+
+	readl_relaxed(wdt->base + RTIWWDSIZECTRL);
+
+	/* enable watchdog */
+	writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
+	return 0;
+}
+
+static int rti_wdt_ping(struct watchdog_device *wdd)
+{
+	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
+
+	/* put watchdog in service state */
+	writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
+	/* put watchdog in active state */
+	writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
+
+	return 0;
+}
+
+static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
+{
+	u64 timer_counter;
+	u32 val;
+	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
+
+	/* if timeout has occurred then return 0 */
+	val = readl_relaxed(wdt->base + RTIWDSTATUS);
+	if (val & DWDST)
+		return 0;
+
+	timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
+
+	do_div(timer_counter, wdt->freq);
+
+	return timer_counter;
+}
+
+static const struct watchdog_info rti_wdt_info = {
+	.options = WDIOF_KEEPALIVEPING,
+	.identity = "K3 RTI Watchdog",
+};
+
+static const struct watchdog_ops rti_wdt_ops = {
+	.owner		= THIS_MODULE,
+	.start		= rti_wdt_start,
+	.ping		= rti_wdt_ping,
+	.get_timeleft	= rti_wdt_get_timeleft,
+};
+
+static int rti_wdt_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+	struct device *dev = &pdev->dev;
+	struct resource *wdt_mem;
+	struct watchdog_device *wdd;
+	struct rti_wdt_device *wdt;
+	struct clk *clk;
+
+	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(clk)) {
+		if (PTR_ERR(clk) != -EPROBE_DEFER)
+			dev_err(dev, "failed to get clock\n");
+		return PTR_ERR(clk);
+	}
+
+	wdt->freq = clk_get_rate(clk);
+	if (!wdt->freq) {
+		dev_err(dev, "Failed to get fck rate.\n");
+		return -EINVAL;
+	}
+
+	devm_clk_put(dev, clk);
+
+	pm_runtime_enable(dev);
+	ret = pm_runtime_get_sync(dev);
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "runtime pm failed\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, wdt);
+
+	wdd = &wdt->wdd;
+	wdd->info = &rti_wdt_info;
+	wdd->ops = &rti_wdt_ops;
+	wdd->min_timeout = 1;
+	wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
+		wdt->freq * 1000;
+	wdd->timeout = DEFAULT_HEARTBEAT;
+	wdd->parent = dev;
+
+	watchdog_init_timeout(wdd, heartbeat, dev);
+
+	watchdog_set_drvdata(wdd, wdt);
+	watchdog_set_nowayout(wdd, 1);
+	watchdog_set_restart_priority(wdd, 128);
+
+	wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	wdt->base = devm_ioremap_resource(dev, wdt_mem);
+	if (IS_ERR(wdt->base)) {
+		ret = PTR_ERR(wdt->base);
+		goto err_iomap;
+	}
+
+	ret = watchdog_register_device(wdd);
+	if (ret) {
+		dev_err(dev, "cannot register watchdog device\n");
+		goto err_iomap;
+	}
+
+	return 0;
+
+err_iomap:
+	pm_runtime_put_sync(&pdev->dev);
+
+	return ret;
+}
+
+static int rti_wdt_remove(struct platform_device *pdev)
+{
+	struct rti_wdt_device *wdt = platform_get_drvdata(pdev);
+
+	watchdog_unregister_device(&wdt->wdd);
+	pm_runtime_put(&pdev->dev);
+
+	return 0;
+}
+
+static const struct of_device_id rti_wdt_of_match[] = {
+	{ .compatible = "ti,rti-wdt", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, rti_wdt_of_match);
+
+static struct platform_driver rti_wdt_driver = {
+	.driver = {
+		.name = "rti-wdt",
+		.of_match_table = rti_wdt_of_match,
+	},
+	.probe = rti_wdt_probe,
+	.remove = rti_wdt_remove,
+};
+
+module_platform_driver(rti_wdt_driver);
+
+MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");
+MODULE_DESCRIPTION("K3 RTI Watchdog Driver");
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat,
+		 "Watchdog heartbeat period in seconds from 1 to "
+		 __MODULE_STRING(MAX_HEARTBEAT) ", default "
+		 __MODULE_STRING(DEFAULT_HEARTBEAT));
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rti-wdt");
-- 
2.17.1

--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

Re: [PATCHv2 3/4] watchdog: Add K3 RTI watchdog support

[Guenter Roeck]

On Mon, Mar 02, 2020 at 10:04:25PM +0200, Tero Kristo wrote:
> Texas Instruments K3 SoCs contain an RTI (Real Time Interrupt) module
> which can be used as a watchdog. This IP provides a support for
> windowed watchdog mode, in which the watchdog must be petted within
> a certain time window. If it is petted either too soon, or too late,
> a watchdog error will be triggered.
> 
> Signed-off-by: Tero Kristo <t-kristo@ti.com>
> ---
> v2:
>   * Added better documentation within the driver code
>   * Dropped fck handle, instead get the fck rate during probe only
>   * Modified the max_hw_heartbeat calculation logic a bit
> 
>  drivers/watchdog/Kconfig   |   8 ++
>  drivers/watchdog/Makefile  |   1 +
>  drivers/watchdog/rti_wdt.c | 254 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 261 insertions(+)
>  create mode 100644 drivers/watchdog/rti_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index cec868f8db3f..81faf47d44a6 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -583,6 +583,14 @@ config DAVINCI_WATCHDOG
>  	  NOTE: once enabled, this timer cannot be disabled.
>  	  Say N if you are unsure.
>  
> +config K3_RTI_WATCHDOG
> +	tristate "Texas Instruments K3 RTI watchdog"
> +	depends on ARCH_K3 || COMPILE_TEST
> +	select WATCHDOG_CORE
> +	help
> +	  Say Y here if you want to include support for the K3 watchdog
> +	  timer (RTI module) available in the K3 generation of processors.
> +
>  config ORION_WATCHDOG
>  	tristate "Orion watchdog"
>  	depends on ARCH_ORION5X || ARCH_DOVE || MACH_DOVE || ARCH_MVEBU || (COMPILE_TEST && !ARCH_EBSA110)
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 2ee352bf3372..6de2e4ceef19 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -57,6 +57,7 @@ obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
>  obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
>  obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
>  obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
> +obj-$(CONFIG_K3_RTI_WATCHDOG) += rti_wdt.o
>  obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
>  obj-$(CONFIG_SUNXI_WATCHDOG) += sunxi_wdt.o
>  obj-$(CONFIG_RN5T618_WATCHDOG) += rn5t618_wdt.o
> diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
> new file mode 100644
> index 000000000000..7a46c40891e2
> --- /dev/null
> +++ b/drivers/watchdog/rti_wdt.c
> @@ -0,0 +1,254 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Watchdog driver for the K3 RTI module
> + *
> + * (c) Copyright 2019-2020 Texas Instruments Inc.
> + * All rights reserved.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/types.h>
> +#include <linux/watchdog.h>
> +
> +#define DEFAULT_HEARTBEAT 60
> +
> +/* Max heartbeat is calculated at 32kHz source clock */
> +#define MAX_HEARTBEAT	1000
> +
> +/* Timer register set definition */
> +#define RTIDWDCTRL	0x90
> +#define RTIDWDPRLD	0x94
> +#define RTIWDSTATUS	0x98
> +#define RTIWDKEY	0x9c
> +#define RTIDWDCNTR	0xa0
> +#define RTIWWDRXCTRL	0xa4
> +#define RTIWWDSIZECTRL	0xa8
> +
> +#define RTIWWDRX_NMI	0xa
> +
> +#define RTIWWDSIZE_50P	0x50
> +
> +#define WDENABLE_KEY	0xa98559da
> +
> +#define WDKEY_SEQ0		0xe51a
> +#define WDKEY_SEQ1		0xa35c
> +
> +#define WDT_PRELOAD_SHIFT	13
> +
> +#define WDT_PRELOAD_MAX		0xfff
> +
> +#define DWDST			BIT(1)
> +
> +static int heartbeat;
> +
> +/*
> + * struct to hold data for each WDT device
> + * @base - base io address of WD device
> + * @freq - source clock frequency of WDT
> + * @wdd  - hold watchdog device as is in WDT core
> + */
> +struct rti_wdt_device {
> +	void __iomem		*base;
> +	unsigned long		freq;
> +	struct watchdog_device	wdd;
> +};
> +
> +static int rti_wdt_start(struct watchdog_device *wdd)
> +{
> +	u32 timer_margin;
> +	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
> +
> +	/* set timeout period */
> +	timer_margin = (u64)wdd->timeout * wdt->freq;
> +	timer_margin >>= WDT_PRELOAD_SHIFT;
> +	if (timer_margin > WDT_PRELOAD_MAX)
> +		timer_margin = WDT_PRELOAD_MAX;
> +	writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
> +
> +	/*
> +	 * RTI only supports a windowed mode, where the watchdog can only
> +	 * be petted during the open window; not too early or not too late.
> +	 * The HW configuration options only allow for the open window size
> +	 * to be 50% or less than that; we obviouly want to configure the open
> +	 * window as large as possible so we select the 50% option. To avoid
> +	 * any glitches, we accommodate 5% safety margin also, so we setup
> +	 * the min_hw_hearbeat at 55% of the timeout period.
> +	 */
> +	wdd->min_hw_heartbeat_ms = 11 * wdd->timeout * 1000 / 20;
> +
> +	/* Generate NMI when wdt expires */
> +	writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
> +
> +	/* Open window size 50%; this is the largest window size available */
> +	writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
> +
> +	readl_relaxed(wdt->base + RTIWWDSIZECTRL);
> +
> +	/* enable watchdog */
> +	writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
> +	return 0;
> +}
> +
> +static int rti_wdt_ping(struct watchdog_device *wdd)
> +{
> +	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
> +
> +	/* put watchdog in service state */
> +	writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
> +	/* put watchdog in active state */
> +	writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
> +
> +	return 0;
> +}
> +
> +static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
> +{
> +	u64 timer_counter;
> +	u32 val;
> +	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
> +
> +	/* if timeout has occurred then return 0 */
> +	val = readl_relaxed(wdt->base + RTIWDSTATUS);
> +	if (val & DWDST)
> +		return 0;
> +
> +	timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
> +
> +	do_div(timer_counter, wdt->freq);
> +
> +	return timer_counter;
> +}
> +
> +static const struct watchdog_info rti_wdt_info = {
> +	.options = WDIOF_KEEPALIVEPING,
> +	.identity = "K3 RTI Watchdog",
> +};
> +
> +static const struct watchdog_ops rti_wdt_ops = {
> +	.owner		= THIS_MODULE,
> +	.start		= rti_wdt_start,
> +	.ping		= rti_wdt_ping,
> +	.get_timeleft	= rti_wdt_get_timeleft,
> +};
> +
> +static int rti_wdt_probe(struct platform_device *pdev)
> +{
> +	int ret = 0;
> +	struct device *dev = &pdev->dev;
> +	struct resource *wdt_mem;
> +	struct watchdog_device *wdd;
> +	struct rti_wdt_device *wdt;
> +	struct clk *clk;
> +
> +	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
> +	if (!wdt)
> +		return -ENOMEM;
> +
> +	clk = devm_clk_get(dev, NULL);
> +	if (IS_ERR(clk)) {
> +		if (PTR_ERR(clk) != -EPROBE_DEFER)
> +			dev_err(dev, "failed to get clock\n");
> +		return PTR_ERR(clk);
> +	}
> +
> +	wdt->freq = clk_get_rate(clk);
> +	if (!wdt->freq) {
> +		dev_err(dev, "Failed to get fck rate.\n");
> +		return -EINVAL;
> +	}
> +
> +	devm_clk_put(dev, clk);
> +
Are you sure about this ? Doesn't this mean that the clock may be stopped ?
Normally the reason for using devm_ functions during probe is that release
functions are called automatically when the device is removed. Calling
the release function dorectly is unusual and most of the time wrong.

Thanks,
Guenter

> +	pm_runtime_enable(dev);
> +	ret = pm_runtime_get_sync(dev);
> +	if (ret) {
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(&pdev->dev, "runtime pm failed\n");
> +		return ret;
> +	}
> +
> +	platform_set_drvdata(pdev, wdt);
> +
> +	wdd = &wdt->wdd;
> +	wdd->info = &rti_wdt_info;
> +	wdd->ops = &rti_wdt_ops;
> +	wdd->min_timeout = 1;
> +	wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
> +		wdt->freq * 1000;
> +	wdd->timeout = DEFAULT_HEARTBEAT;
> +	wdd->parent = dev;
> +
> +	watchdog_init_timeout(wdd, heartbeat, dev);
> +
> +	watchdog_set_drvdata(wdd, wdt);
> +	watchdog_set_nowayout(wdd, 1);
> +	watchdog_set_restart_priority(wdd, 128);
> +
> +	wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	wdt->base = devm_ioremap_resource(dev, wdt_mem);
> +	if (IS_ERR(wdt->base)) {
> +		ret = PTR_ERR(wdt->base);
> +		goto err_iomap;
> +	}
> +
> +	ret = watchdog_register_device(wdd);
> +	if (ret) {
> +		dev_err(dev, "cannot register watchdog device\n");
> +		goto err_iomap;
> +	}
> +
> +	return 0;
> +
> +err_iomap:
> +	pm_runtime_put_sync(&pdev->dev);
> +
> +	return ret;
> +}
> +
> +static int rti_wdt_remove(struct platform_device *pdev)
> +{
> +	struct rti_wdt_device *wdt = platform_get_drvdata(pdev);
> +
> +	watchdog_unregister_device(&wdt->wdd);
> +	pm_runtime_put(&pdev->dev);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id rti_wdt_of_match[] = {
> +	{ .compatible = "ti,rti-wdt", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, rti_wdt_of_match);
> +
> +static struct platform_driver rti_wdt_driver = {
> +	.driver = {
> +		.name = "rti-wdt",
> +		.of_match_table = rti_wdt_of_match,
> +	},
> +	.probe = rti_wdt_probe,
> +	.remove = rti_wdt_remove,
> +};
> +
> +module_platform_driver(rti_wdt_driver);
> +
> +MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");
> +MODULE_DESCRIPTION("K3 RTI Watchdog Driver");
> +
> +module_param(heartbeat, int, 0);
> +MODULE_PARM_DESC(heartbeat,
> +		 "Watchdog heartbeat period in seconds from 1 to "
> +		 __MODULE_STRING(MAX_HEARTBEAT) ", default "
> +		 __MODULE_STRING(DEFAULT_HEARTBEAT));
> +
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:rti-wdt");
> -- 
> 2.17.1
> 
> --
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

Re: [PATCHv2 3/4] watchdog: Add K3 RTI watchdog support

[Tero Kristo]

On 03/03/2020 23:18, Guenter Roeck wrote:
> On Mon, Mar 02, 2020 at 10:04:25PM +0200, Tero Kristo wrote:
>> Texas Instruments K3 SoCs contain an RTI (Real Time Interrupt) module
>> which can be used as a watchdog. This IP provides a support for
>> windowed watchdog mode, in which the watchdog must be petted within
>> a certain time window. If it is petted either too soon, or too late,
>> a watchdog error will be triggered.
>>
>> Signed-off-by: Tero Kristo <t-kristo@ti.com>
>> ---
>> v2:
>>    * Added better documentation within the driver code
>>    * Dropped fck handle, instead get the fck rate during probe only
>>    * Modified the max_hw_heartbeat calculation logic a bit
>>
>>   drivers/watchdog/Kconfig   |   8 ++
>>   drivers/watchdog/Makefile  |   1 +
>>   drivers/watchdog/rti_wdt.c | 254 +++++++++++++++++++++++++++++++++++++
>>   3 files changed, 261 insertions(+)
>>   create mode 100644 drivers/watchdog/rti_wdt.c
>>
>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> index cec868f8db3f..81faf47d44a6 100644
>> --- a/drivers/watchdog/Kconfig
>> +++ b/drivers/watchdog/Kconfig
>> @@ -583,6 +583,14 @@ config DAVINCI_WATCHDOG
>>   	  NOTE: once enabled, this timer cannot be disabled.
>>   	  Say N if you are unsure.
>>   
>> +config K3_RTI_WATCHDOG
>> +	tristate "Texas Instruments K3 RTI watchdog"
>> +	depends on ARCH_K3 || COMPILE_TEST
>> +	select WATCHDOG_CORE
>> +	help
>> +	  Say Y here if you want to include support for the K3 watchdog
>> +	  timer (RTI module) available in the K3 generation of processors.
>> +
>>   config ORION_WATCHDOG
>>   	tristate "Orion watchdog"
>>   	depends on ARCH_ORION5X || ARCH_DOVE || MACH_DOVE || ARCH_MVEBU || (COMPILE_TEST && !ARCH_EBSA110)
>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
>> index 2ee352bf3372..6de2e4ceef19 100644
>> --- a/drivers/watchdog/Makefile
>> +++ b/drivers/watchdog/Makefile
>> @@ -57,6 +57,7 @@ obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
>>   obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
>>   obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
>>   obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
>> +obj-$(CONFIG_K3_RTI_WATCHDOG) += rti_wdt.o
>>   obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
>>   obj-$(CONFIG_SUNXI_WATCHDOG) += sunxi_wdt.o
>>   obj-$(CONFIG_RN5T618_WATCHDOG) += rn5t618_wdt.o
>> diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
>> new file mode 100644
>> index 000000000000..7a46c40891e2
>> --- /dev/null
>> +++ b/drivers/watchdog/rti_wdt.c
>> @@ -0,0 +1,254 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Watchdog driver for the K3 RTI module
>> + *
>> + * (c) Copyright 2019-2020 Texas Instruments Inc.
>> + * All rights reserved.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/device.h>
>> +#include <linux/err.h>
>> +#include <linux/io.h>
>> +#include <linux/kernel.h>
>> +#include <linux/mod_devicetable.h>
>> +#include <linux/module.h>
>> +#include <linux/moduleparam.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/types.h>
>> +#include <linux/watchdog.h>
>> +
>> +#define DEFAULT_HEARTBEAT 60
>> +
>> +/* Max heartbeat is calculated at 32kHz source clock */
>> +#define MAX_HEARTBEAT	1000
>> +
>> +/* Timer register set definition */
>> +#define RTIDWDCTRL	0x90
>> +#define RTIDWDPRLD	0x94
>> +#define RTIWDSTATUS	0x98
>> +#define RTIWDKEY	0x9c
>> +#define RTIDWDCNTR	0xa0
>> +#define RTIWWDRXCTRL	0xa4
>> +#define RTIWWDSIZECTRL	0xa8
>> +
>> +#define RTIWWDRX_NMI	0xa
>> +
>> +#define RTIWWDSIZE_50P	0x50
>> +
>> +#define WDENABLE_KEY	0xa98559da
>> +
>> +#define WDKEY_SEQ0		0xe51a
>> +#define WDKEY_SEQ1		0xa35c
>> +
>> +#define WDT_PRELOAD_SHIFT	13
>> +
>> +#define WDT_PRELOAD_MAX		0xfff
>> +
>> +#define DWDST			BIT(1)
>> +
>> +static int heartbeat;
>> +
>> +/*
>> + * struct to hold data for each WDT device
>> + * @base - base io address of WD device
>> + * @freq - source clock frequency of WDT
>> + * @wdd  - hold watchdog device as is in WDT core
>> + */
>> +struct rti_wdt_device {
>> +	void __iomem		*base;
>> +	unsigned long		freq;
>> +	struct watchdog_device	wdd;
>> +};
>> +
>> +static int rti_wdt_start(struct watchdog_device *wdd)
>> +{
>> +	u32 timer_margin;
>> +	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
>> +
>> +	/* set timeout period */
>> +	timer_margin = (u64)wdd->timeout * wdt->freq;
>> +	timer_margin >>= WDT_PRELOAD_SHIFT;
>> +	if (timer_margin > WDT_PRELOAD_MAX)
>> +		timer_margin = WDT_PRELOAD_MAX;
>> +	writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
>> +
>> +	/*
>> +	 * RTI only supports a windowed mode, where the watchdog can only
>> +	 * be petted during the open window; not too early or not too late.
>> +	 * The HW configuration options only allow for the open window size
>> +	 * to be 50% or less than that; we obviouly want to configure the open
>> +	 * window as large as possible so we select the 50% option. To avoid
>> +	 * any glitches, we accommodate 5% safety margin also, so we setup
>> +	 * the min_hw_hearbeat at 55% of the timeout period.
>> +	 */
>> +	wdd->min_hw_heartbeat_ms = 11 * wdd->timeout * 1000 / 20;
>> +
>> +	/* Generate NMI when wdt expires */
>> +	writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
>> +
>> +	/* Open window size 50%; this is the largest window size available */
>> +	writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
>> +
>> +	readl_relaxed(wdt->base + RTIWWDSIZECTRL);
>> +
>> +	/* enable watchdog */
>> +	writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
>> +	return 0;
>> +}
>> +
>> +static int rti_wdt_ping(struct watchdog_device *wdd)
>> +{
>> +	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
>> +
>> +	/* put watchdog in service state */
>> +	writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
>> +	/* put watchdog in active state */
>> +	writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
>> +
>> +	return 0;
>> +}
>> +
>> +static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
>> +{
>> +	u64 timer_counter;
>> +	u32 val;
>> +	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
>> +
>> +	/* if timeout has occurred then return 0 */
>> +	val = readl_relaxed(wdt->base + RTIWDSTATUS);
>> +	if (val & DWDST)
>> +		return 0;
>> +
>> +	timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
>> +
>> +	do_div(timer_counter, wdt->freq);
>> +
>> +	return timer_counter;
>> +}
>> +
>> +static const struct watchdog_info rti_wdt_info = {
>> +	.options = WDIOF_KEEPALIVEPING,
>> +	.identity = "K3 RTI Watchdog",
>> +};
>> +
>> +static const struct watchdog_ops rti_wdt_ops = {
>> +	.owner		= THIS_MODULE,
>> +	.start		= rti_wdt_start,
>> +	.ping		= rti_wdt_ping,
>> +	.get_timeleft	= rti_wdt_get_timeleft,
>> +};
>> +
>> +static int rti_wdt_probe(struct platform_device *pdev)
>> +{
>> +	int ret = 0;
>> +	struct device *dev = &pdev->dev;
>> +	struct resource *wdt_mem;
>> +	struct watchdog_device *wdd;
>> +	struct rti_wdt_device *wdt;
>> +	struct clk *clk;
>> +
>> +	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
>> +	if (!wdt)
>> +		return -ENOMEM;
>> +
>> +	clk = devm_clk_get(dev, NULL);
>> +	if (IS_ERR(clk)) {
>> +		if (PTR_ERR(clk) != -EPROBE_DEFER)
>> +			dev_err(dev, "failed to get clock\n");
>> +		return PTR_ERR(clk);
>> +	}
>> +
>> +	wdt->freq = clk_get_rate(clk);
>> +	if (!wdt->freq) {
>> +		dev_err(dev, "Failed to get fck rate.\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	devm_clk_put(dev, clk);
>> +
> Are you sure about this ? Doesn't this mean that the clock may be stopped ?
> Normally the reason for using devm_ functions during probe is that release
> functions are called automatically when the device is removed. Calling
> the release function dorectly is unusual and most of the time wrong.

clk_get / clk_put does not enable / disable a clock by itself, this is 
just used to fetch a clock handle. But you are right, we are never 
calling clk_enable on it either, because at least the 32kHz clock we are 
interested in is of type always-on and can never be disabled.

I can keep the clock handle and call enable/disable on it in the 
probe/remove if you think that would be neater.

-Tero

> 
> Thanks,
> Guenter
> 
>> +	pm_runtime_enable(dev);
>> +	ret = pm_runtime_get_sync(dev);
>> +	if (ret) {
>> +		if (ret != -EPROBE_DEFER)
>> +			dev_err(&pdev->dev, "runtime pm failed\n");
>> +		return ret;
>> +	}
>> +
>> +	platform_set_drvdata(pdev, wdt);
>> +
>> +	wdd = &wdt->wdd;
>> +	wdd->info = &rti_wdt_info;
>> +	wdd->ops = &rti_wdt_ops;
>> +	wdd->min_timeout = 1;
>> +	wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
>> +		wdt->freq * 1000;
>> +	wdd->timeout = DEFAULT_HEARTBEAT;
>> +	wdd->parent = dev;
>> +
>> +	watchdog_init_timeout(wdd, heartbeat, dev);
>> +
>> +	watchdog_set_drvdata(wdd, wdt);
>> +	watchdog_set_nowayout(wdd, 1);
>> +	watchdog_set_restart_priority(wdd, 128);
>> +
>> +	wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	wdt->base = devm_ioremap_resource(dev, wdt_mem);
>> +	if (IS_ERR(wdt->base)) {
>> +		ret = PTR_ERR(wdt->base);
>> +		goto err_iomap;
>> +	}
>> +
>> +	ret = watchdog_register_device(wdd);
>> +	if (ret) {
>> +		dev_err(dev, "cannot register watchdog device\n");
>> +		goto err_iomap;
>> +	}
>> +
>> +	return 0;
>> +
>> +err_iomap:
>> +	pm_runtime_put_sync(&pdev->dev);
>> +
>> +	return ret;
>> +}
>> +
>> +static int rti_wdt_remove(struct platform_device *pdev)
>> +{
>> +	struct rti_wdt_device *wdt = platform_get_drvdata(pdev);
>> +
>> +	watchdog_unregister_device(&wdt->wdd);
>> +	pm_runtime_put(&pdev->dev);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id rti_wdt_of_match[] = {
>> +	{ .compatible = "ti,rti-wdt", },
>> +	{},
>> +};
>> +MODULE_DEVICE_TABLE(of, rti_wdt_of_match);
>> +
>> +static struct platform_driver rti_wdt_driver = {
>> +	.driver = {
>> +		.name = "rti-wdt",
>> +		.of_match_table = rti_wdt_of_match,
>> +	},
>> +	.probe = rti_wdt_probe,
>> +	.remove = rti_wdt_remove,
>> +};
>> +
>> +module_platform_driver(rti_wdt_driver);
>> +
>> +MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");
>> +MODULE_DESCRIPTION("K3 RTI Watchdog Driver");
>> +
>> +module_param(heartbeat, int, 0);
>> +MODULE_PARM_DESC(heartbeat,
>> +		 "Watchdog heartbeat period in seconds from 1 to "
>> +		 __MODULE_STRING(MAX_HEARTBEAT) ", default "
>> +		 __MODULE_STRING(DEFAULT_HEARTBEAT));
>> +
>> +MODULE_LICENSE("GPL");
>> +MODULE_ALIAS("platform:rti-wdt");
>> -- 
>> 2.17.1
>>
>> --

--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

Re: [PATCHv2 3/4] watchdog: Add K3 RTI watchdog support

[Guenter Roeck]

On 3/3/20 10:57 PM, Tero Kristo wrote:
> On 03/03/2020 23:18, Guenter Roeck wrote:
>> On Mon, Mar 02, 2020 at 10:04:25PM +0200, Tero Kristo wrote:
>>> Texas Instruments K3 SoCs contain an RTI (Real Time Interrupt) module
>>> which can be used as a watchdog. This IP provides a support for
>>> windowed watchdog mode, in which the watchdog must be petted within
>>> a certain time window. If it is petted either too soon, or too late,
>>> a watchdog error will be triggered.
>>>
>>> Signed-off-by: Tero Kristo <t-kristo@ti.com>
>>> ---
>>> v2:
>>>    * Added better documentation within the driver code
>>>    * Dropped fck handle, instead get the fck rate during probe only
>>>    * Modified the max_hw_heartbeat calculation logic a bit
>>>
>>>   drivers/watchdog/Kconfig   |   8 ++
>>>   drivers/watchdog/Makefile  |   1 +
>>>   drivers/watchdog/rti_wdt.c | 254 +++++++++++++++++++++++++++++++++++++
>>>   3 files changed, 261 insertions(+)
>>>   create mode 100644 drivers/watchdog/rti_wdt.c
>>>
>>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>>> index cec868f8db3f..81faf47d44a6 100644
>>> --- a/drivers/watchdog/Kconfig
>>> +++ b/drivers/watchdog/Kconfig
>>> @@ -583,6 +583,14 @@ config DAVINCI_WATCHDOG
>>>         NOTE: once enabled, this timer cannot be disabled.
>>>         Say N if you are unsure.
>>>   +config K3_RTI_WATCHDOG
>>> +    tristate "Texas Instruments K3 RTI watchdog"
>>> +    depends on ARCH_K3 || COMPILE_TEST
>>> +    select WATCHDOG_CORE
>>> +    help
>>> +      Say Y here if you want to include support for the K3 watchdog
>>> +      timer (RTI module) available in the K3 generation of processors.
>>> +
>>>   config ORION_WATCHDOG
>>>       tristate "Orion watchdog"
>>>       depends on ARCH_ORION5X || ARCH_DOVE || MACH_DOVE || ARCH_MVEBU || (COMPILE_TEST && !ARCH_EBSA110)
>>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
>>> index 2ee352bf3372..6de2e4ceef19 100644
>>> --- a/drivers/watchdog/Makefile
>>> +++ b/drivers/watchdog/Makefile
>>> @@ -57,6 +57,7 @@ obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
>>>   obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
>>>   obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
>>>   obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
>>> +obj-$(CONFIG_K3_RTI_WATCHDOG) += rti_wdt.o
>>>   obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
>>>   obj-$(CONFIG_SUNXI_WATCHDOG) += sunxi_wdt.o
>>>   obj-$(CONFIG_RN5T618_WATCHDOG) += rn5t618_wdt.o
>>> diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
>>> new file mode 100644
>>> index 000000000000..7a46c40891e2
>>> --- /dev/null
>>> +++ b/drivers/watchdog/rti_wdt.c
>>> @@ -0,0 +1,254 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/*
>>> + * Watchdog driver for the K3 RTI module
>>> + *
>>> + * (c) Copyright 2019-2020 Texas Instruments Inc.
>>> + * All rights reserved.
>>> + */
>>> +
>>> +#include <linux/clk.h>
>>> +#include <linux/device.h>
>>> +#include <linux/err.h>
>>> +#include <linux/io.h>
>>> +#include <linux/kernel.h>
>>> +#include <linux/mod_devicetable.h>
>>> +#include <linux/module.h>
>>> +#include <linux/moduleparam.h>
>>> +#include <linux/platform_device.h>
>>> +#include <linux/pm_runtime.h>
>>> +#include <linux/types.h>
>>> +#include <linux/watchdog.h>
>>> +
>>> +#define DEFAULT_HEARTBEAT 60
>>> +
>>> +/* Max heartbeat is calculated at 32kHz source clock */
>>> +#define MAX_HEARTBEAT    1000
>>> +
>>> +/* Timer register set definition */
>>> +#define RTIDWDCTRL    0x90
>>> +#define RTIDWDPRLD    0x94
>>> +#define RTIWDSTATUS    0x98
>>> +#define RTIWDKEY    0x9c
>>> +#define RTIDWDCNTR    0xa0
>>> +#define RTIWWDRXCTRL    0xa4
>>> +#define RTIWWDSIZECTRL    0xa8
>>> +
>>> +#define RTIWWDRX_NMI    0xa
>>> +
>>> +#define RTIWWDSIZE_50P    0x50
>>> +
>>> +#define WDENABLE_KEY    0xa98559da
>>> +
>>> +#define WDKEY_SEQ0        0xe51a
>>> +#define WDKEY_SEQ1        0xa35c
>>> +
>>> +#define WDT_PRELOAD_SHIFT    13
>>> +
>>> +#define WDT_PRELOAD_MAX        0xfff
>>> +
>>> +#define DWDST            BIT(1)
>>> +
>>> +static int heartbeat;
>>> +
>>> +/*
>>> + * struct to hold data for each WDT device
>>> + * @base - base io address of WD device
>>> + * @freq - source clock frequency of WDT
>>> + * @wdd  - hold watchdog device as is in WDT core
>>> + */
>>> +struct rti_wdt_device {
>>> +    void __iomem        *base;
>>> +    unsigned long        freq;
>>> +    struct watchdog_device    wdd;
>>> +};
>>> +
>>> +static int rti_wdt_start(struct watchdog_device *wdd)
>>> +{
>>> +    u32 timer_margin;
>>> +    struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
>>> +
>>> +    /* set timeout period */
>>> +    timer_margin = (u64)wdd->timeout * wdt->freq;
>>> +    timer_margin >>= WDT_PRELOAD_SHIFT;
>>> +    if (timer_margin > WDT_PRELOAD_MAX)
>>> +        timer_margin = WDT_PRELOAD_MAX;
>>> +    writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
>>> +
>>> +    /*
>>> +     * RTI only supports a windowed mode, where the watchdog can only
>>> +     * be petted during the open window; not too early or not too late.
>>> +     * The HW configuration options only allow for the open window size
>>> +     * to be 50% or less than that; we obviouly want to configure the open
>>> +     * window as large as possible so we select the 50% option. To avoid
>>> +     * any glitches, we accommodate 5% safety margin also, so we setup
>>> +     * the min_hw_hearbeat at 55% of the timeout period.
>>> +     */
>>> +    wdd->min_hw_heartbeat_ms = 11 * wdd->timeout * 1000 / 20;
>>> +
>>> +    /* Generate NMI when wdt expires */
>>> +    writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
>>> +
>>> +    /* Open window size 50%; this is the largest window size available */
>>> +    writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
>>> +
>>> +    readl_relaxed(wdt->base + RTIWWDSIZECTRL);
>>> +
>>> +    /* enable watchdog */
>>> +    writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
>>> +    return 0;
>>> +}
>>> +
>>> +static int rti_wdt_ping(struct watchdog_device *wdd)
>>> +{
>>> +    struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
>>> +
>>> +    /* put watchdog in service state */
>>> +    writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
>>> +    /* put watchdog in active state */
>>> +    writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
>>> +{
>>> +    u64 timer_counter;
>>> +    u32 val;
>>> +    struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
>>> +
>>> +    /* if timeout has occurred then return 0 */
>>> +    val = readl_relaxed(wdt->base + RTIWDSTATUS);
>>> +    if (val & DWDST)
>>> +        return 0;
>>> +
>>> +    timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
>>> +
>>> +    do_div(timer_counter, wdt->freq);
>>> +
>>> +    return timer_counter;
>>> +}
>>> +
>>> +static const struct watchdog_info rti_wdt_info = {
>>> +    .options = WDIOF_KEEPALIVEPING,
>>> +    .identity = "K3 RTI Watchdog",
>>> +};
>>> +
>>> +static const struct watchdog_ops rti_wdt_ops = {
>>> +    .owner        = THIS_MODULE,
>>> +    .start        = rti_wdt_start,
>>> +    .ping        = rti_wdt_ping,
>>> +    .get_timeleft    = rti_wdt_get_timeleft,
>>> +};
>>> +
>>> +static int rti_wdt_probe(struct platform_device *pdev)
>>> +{
>>> +    int ret = 0;
>>> +    struct device *dev = &pdev->dev;
>>> +    struct resource *wdt_mem;
>>> +    struct watchdog_device *wdd;
>>> +    struct rti_wdt_device *wdt;
>>> +    struct clk *clk;
>>> +
>>> +    wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
>>> +    if (!wdt)
>>> +        return -ENOMEM;
>>> +
>>> +    clk = devm_clk_get(dev, NULL);
>>> +    if (IS_ERR(clk)) {
>>> +        if (PTR_ERR(clk) != -EPROBE_DEFER)
>>> +            dev_err(dev, "failed to get clock\n");
>>> +        return PTR_ERR(clk);
>>> +    }
>>> +
>>> +    wdt->freq = clk_get_rate(clk);
>>> +    if (!wdt->freq) {
>>> +        dev_err(dev, "Failed to get fck rate.\n");
>>> +        return -EINVAL;
>>> +    }
>>> +
>>> +    devm_clk_put(dev, clk);
>>> +
>> Are you sure about this ? Doesn't this mean that the clock may be stopped ?
>> Normally the reason for using devm_ functions during probe is that release
>> functions are called automatically when the device is removed. Calling
>> the release function dorectly is unusual and most of the time wrong.
> 
> clk_get / clk_put does not enable / disable a clock by itself, this is just used to fetch a clock handle. But you are right, we are never calling clk_enable on it either, because at least the 32kHz clock we are interested in is of type always-on and can never be disabled.
> 
> I can keep the clock handle and call enable/disable on it in the probe/remove if you think that would be neater.
> 

If it isn't needed to be held, you should use clk_get / clk_put,
and not the devm_ functions.

Guenter

[PATCHv3 3/4] watchdog: Add K3 RTI watchdog support

[Tero Kristo]

Texas Instruments K3 SoCs contain an RTI (Real Time Interrupt) module
which can be used as a watchdog. This IP provides a support for
windowed watchdog mode, in which the watchdog must be petted within
a certain time window. If it is petted either too soon, or too late,
a watchdog error will be triggered.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
---
v3:
  * changed to use clk_get/put instead of devm_* versions of this

v2:
  * Added better documentation within the driver code
  * Dropped fck handle, instead get the fck rate during probe only
  * Modified the max_hw_heartbeat calculation logic a bit

 drivers/watchdog/Kconfig   |   8 ++
 drivers/watchdog/Makefile  |   1 +
 drivers/watchdog/rti_wdt.c | 255 +++++++++++++++++++++++++++++++++++++
 3 files changed, 261 insertions(+)
 create mode 100644 drivers/watchdog/rti_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index cec868f8db3f..81faf47d44a6 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -583,6 +583,14 @@ config DAVINCI_WATCHDOG
 	  NOTE: once enabled, this timer cannot be disabled.
 	  Say N if you are unsure.
 
+config K3_RTI_WATCHDOG
+	tristate "Texas Instruments K3 RTI watchdog"
+	depends on ARCH_K3 || COMPILE_TEST
+	select WATCHDOG_CORE
+	help
+	  Say Y here if you want to include support for the K3 watchdog
+	  timer (RTI module) available in the K3 generation of processors.
+
 config ORION_WATCHDOG
 	tristate "Orion watchdog"
 	depends on ARCH_ORION5X || ARCH_DOVE || MACH_DOVE || ARCH_MVEBU || (COMPILE_TEST && !ARCH_EBSA110)
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 2ee352bf3372..6de2e4ceef19 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -57,6 +57,7 @@ obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
 obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
 obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
 obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
+obj-$(CONFIG_K3_RTI_WATCHDOG) += rti_wdt.o
 obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
 obj-$(CONFIG_SUNXI_WATCHDOG) += sunxi_wdt.o
 obj-$(CONFIG_RN5T618_WATCHDOG) += rn5t618_wdt.o
diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
new file mode 100644
index 000000000000..7a46c40891e2
--- /dev/null
+++ b/drivers/watchdog/rti_wdt.c
@@ -0,0 +1,255 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Watchdog driver for the K3 RTI module
+ *
+ * (c) Copyright 2019-2020 Texas Instruments Inc.
+ * All rights reserved.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+#define DEFAULT_HEARTBEAT 60
+
+/* Max heartbeat is calculated at 32kHz source clock */
+#define MAX_HEARTBEAT	1000
+
+/* Timer register set definition */
+#define RTIDWDCTRL	0x90
+#define RTIDWDPRLD	0x94
+#define RTIWDSTATUS	0x98
+#define RTIWDKEY	0x9c
+#define RTIDWDCNTR	0xa0
+#define RTIWWDRXCTRL	0xa4
+#define RTIWWDSIZECTRL	0xa8
+
+#define RTIWWDRX_NMI	0xa
+
+#define RTIWWDSIZE_50P	0x50
+
+#define WDENABLE_KEY	0xa98559da
+
+#define WDKEY_SEQ0		0xe51a
+#define WDKEY_SEQ1		0xa35c
+
+#define WDT_PRELOAD_SHIFT	13
+
+#define WDT_PRELOAD_MAX		0xfff
+
+#define DWDST			BIT(1)
+
+static int heartbeat;
+
+/*
+ * struct to hold data for each WDT device
+ * @base - base io address of WD device
+ * @freq - source clock frequency of WDT
+ * @wdd  - hold watchdog device as is in WDT core
+ */
+struct rti_wdt_device {
+	void __iomem		*base;
+	unsigned long		freq;
+	struct watchdog_device	wdd;
+};
+
+static int rti_wdt_start(struct watchdog_device *wdd)
+{
+	u32 timer_margin;
+	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
+
+	/* set timeout period */
+	timer_margin = (u64)wdd->timeout * wdt->freq;
+	timer_margin >>= WDT_PRELOAD_SHIFT;
+	if (timer_margin > WDT_PRELOAD_MAX)
+		timer_margin = WDT_PRELOAD_MAX;
+	writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
+
+	/*
+	 * RTI only supports a windowed mode, where the watchdog can only
+	 * be petted during the open window; not too early or not too late.
+	 * The HW configuration options only allow for the open window size
+	 * to be 50% or less than that; we obviouly want to configure the open
+	 * window as large as possible so we select the 50% option. To avoid
+	 * any glitches, we accommodate 5% safety margin also, so we setup
+	 * the min_hw_hearbeat at 55% of the timeout period.
+	 */
+	wdd->min_hw_heartbeat_ms = 11 * wdd->timeout * 1000 / 20;
+
+	/* Generate NMI when wdt expires */
+	writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
+
+	/* Open window size 50%; this is the largest window size available */
+	writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
+
+	readl_relaxed(wdt->base + RTIWWDSIZECTRL);
+
+	/* enable watchdog */
+	writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
+	return 0;
+}
+
+static int rti_wdt_ping(struct watchdog_device *wdd)
+{
+	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
+
+	/* put watchdog in service state */
+	writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
+	/* put watchdog in active state */
+	writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
+
+	return 0;
+}
+
+static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
+{
+	u64 timer_counter;
+	u32 val;
+	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
+
+	/* if timeout has occurred then return 0 */
+	val = readl_relaxed(wdt->base + RTIWDSTATUS);
+	if (val & DWDST)
+		return 0;
+
+	timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
+
+	do_div(timer_counter, wdt->freq);
+
+	return timer_counter;
+}
+
+static const struct watchdog_info rti_wdt_info = {
+	.options = WDIOF_KEEPALIVEPING,
+	.identity = "K3 RTI Watchdog",
+};
+
+static const struct watchdog_ops rti_wdt_ops = {
+	.owner		= THIS_MODULE,
+	.start		= rti_wdt_start,
+	.ping		= rti_wdt_ping,
+	.get_timeleft	= rti_wdt_get_timeleft,
+};
+
+static int rti_wdt_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+	struct device *dev = &pdev->dev;
+	struct resource *wdt_mem;
+	struct watchdog_device *wdd;
+	struct rti_wdt_device *wdt;
+	struct clk *clk;
+
+	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	clk = clk_get(dev, NULL);
+	if (IS_ERR(clk)) {
+		if (PTR_ERR(clk) != -EPROBE_DEFER)
+			dev_err(dev, "failed to get clock\n");
+		return PTR_ERR(clk);
+	}
+
+	wdt->freq = clk_get_rate(clk);
+
+	clk_put(clk);
+
+	if (!wdt->freq) {
+		dev_err(dev, "Failed to get fck rate.\n");
+		return -EINVAL;
+	}
+
+	pm_runtime_enable(dev);
+	ret = pm_runtime_get_sync(dev);
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "runtime pm failed\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, wdt);
+
+	wdd = &wdt->wdd;
+	wdd->info = &rti_wdt_info;
+	wdd->ops = &rti_wdt_ops;
+	wdd->min_timeout = 1;
+	wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
+		wdt->freq * 1000;
+	wdd->timeout = DEFAULT_HEARTBEAT;
+	wdd->parent = dev;
+
+	watchdog_init_timeout(wdd, heartbeat, dev);
+
+	watchdog_set_drvdata(wdd, wdt);
+	watchdog_set_nowayout(wdd, 1);
+	watchdog_set_restart_priority(wdd, 128);
+
+	wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	wdt->base = devm_ioremap_resource(dev, wdt_mem);
+	if (IS_ERR(wdt->base)) {
+		ret = PTR_ERR(wdt->base);
+		goto err_iomap;
+	}
+
+	ret = watchdog_register_device(wdd);
+	if (ret) {
+		dev_err(dev, "cannot register watchdog device\n");
+		goto err_iomap;
+	}
+
+	return 0;
+
+err_iomap:
+	pm_runtime_put_sync(&pdev->dev);
+
+	return ret;
+}
+
+static int rti_wdt_remove(struct platform_device *pdev)
+{
+	struct rti_wdt_device *wdt = platform_get_drvdata(pdev);
+
+	watchdog_unregister_device(&wdt->wdd);
+	pm_runtime_put(&pdev->dev);
+
+	return 0;
+}
+
+static const struct of_device_id rti_wdt_of_match[] = {
+	{ .compatible = "ti,rti-wdt", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, rti_wdt_of_match);
+
+static struct platform_driver rti_wdt_driver = {
+	.driver = {
+		.name = "rti-wdt",
+		.of_match_table = rti_wdt_of_match,
+	},
+	.probe = rti_wdt_probe,
+	.remove = rti_wdt_remove,
+};
+
+module_platform_driver(rti_wdt_driver);
+
+MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");
+MODULE_DESCRIPTION("K3 RTI Watchdog Driver");
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat,
+		 "Watchdog heartbeat period in seconds from 1 to "
+		 __MODULE_STRING(MAX_HEARTBEAT) ", default "
+		 __MODULE_STRING(DEFAULT_HEARTBEAT));
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rti-wdt");
-- 
2.17.1

--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

Re: [PATCHv3 3/4] watchdog: Add K3 RTI watchdog support

[Guenter Roeck]

On Wed, Mar 04, 2020 at 12:42:14PM +0200, Tero Kristo wrote:
> Texas Instruments K3 SoCs contain an RTI (Real Time Interrupt) module
> which can be used as a watchdog. This IP provides a support for
> windowed watchdog mode, in which the watchdog must be petted within
> a certain time window. If it is petted either too soon, or too late,
> a watchdog error will be triggered.
> 
> Signed-off-by: Tero Kristo <t-kristo@ti.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
> v3:
>   * changed to use clk_get/put instead of devm_* versions of this
> 
> v2:
>   * Added better documentation within the driver code
>   * Dropped fck handle, instead get the fck rate during probe only
>   * Modified the max_hw_heartbeat calculation logic a bit
> 
>  drivers/watchdog/Kconfig   |   8 ++
>  drivers/watchdog/Makefile  |   1 +
>  drivers/watchdog/rti_wdt.c | 255 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 261 insertions(+)
>  create mode 100644 drivers/watchdog/rti_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index cec868f8db3f..81faf47d44a6 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -583,6 +583,14 @@ config DAVINCI_WATCHDOG
>  	  NOTE: once enabled, this timer cannot be disabled.
>  	  Say N if you are unsure.
>  
> +config K3_RTI_WATCHDOG
> +	tristate "Texas Instruments K3 RTI watchdog"
> +	depends on ARCH_K3 || COMPILE_TEST
> +	select WATCHDOG_CORE
> +	help
> +	  Say Y here if you want to include support for the K3 watchdog
> +	  timer (RTI module) available in the K3 generation of processors.
> +
>  config ORION_WATCHDOG
>  	tristate "Orion watchdog"
>  	depends on ARCH_ORION5X || ARCH_DOVE || MACH_DOVE || ARCH_MVEBU || (COMPILE_TEST && !ARCH_EBSA110)
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 2ee352bf3372..6de2e4ceef19 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -57,6 +57,7 @@ obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
>  obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
>  obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
>  obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
> +obj-$(CONFIG_K3_RTI_WATCHDOG) += rti_wdt.o
>  obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
>  obj-$(CONFIG_SUNXI_WATCHDOG) += sunxi_wdt.o
>  obj-$(CONFIG_RN5T618_WATCHDOG) += rn5t618_wdt.o
> diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
> new file mode 100644
> index 000000000000..7a46c40891e2
> --- /dev/null
> +++ b/drivers/watchdog/rti_wdt.c
> @@ -0,0 +1,255 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Watchdog driver for the K3 RTI module
> + *
> + * (c) Copyright 2019-2020 Texas Instruments Inc.
> + * All rights reserved.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/types.h>
> +#include <linux/watchdog.h>
> +
> +#define DEFAULT_HEARTBEAT 60
> +
> +/* Max heartbeat is calculated at 32kHz source clock */
> +#define MAX_HEARTBEAT	1000
> +
> +/* Timer register set definition */
> +#define RTIDWDCTRL	0x90
> +#define RTIDWDPRLD	0x94
> +#define RTIWDSTATUS	0x98
> +#define RTIWDKEY	0x9c
> +#define RTIDWDCNTR	0xa0
> +#define RTIWWDRXCTRL	0xa4
> +#define RTIWWDSIZECTRL	0xa8
> +
> +#define RTIWWDRX_NMI	0xa
> +
> +#define RTIWWDSIZE_50P	0x50
> +
> +#define WDENABLE_KEY	0xa98559da
> +
> +#define WDKEY_SEQ0		0xe51a
> +#define WDKEY_SEQ1		0xa35c
> +
> +#define WDT_PRELOAD_SHIFT	13
> +
> +#define WDT_PRELOAD_MAX		0xfff
> +
> +#define DWDST			BIT(1)
> +
> +static int heartbeat;
> +
> +/*
> + * struct to hold data for each WDT device
> + * @base - base io address of WD device
> + * @freq - source clock frequency of WDT
> + * @wdd  - hold watchdog device as is in WDT core
> + */
> +struct rti_wdt_device {
> +	void __iomem		*base;
> +	unsigned long		freq;
> +	struct watchdog_device	wdd;
> +};
> +
> +static int rti_wdt_start(struct watchdog_device *wdd)
> +{
> +	u32 timer_margin;
> +	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
> +
> +	/* set timeout period */
> +	timer_margin = (u64)wdd->timeout * wdt->freq;
> +	timer_margin >>= WDT_PRELOAD_SHIFT;
> +	if (timer_margin > WDT_PRELOAD_MAX)
> +		timer_margin = WDT_PRELOAD_MAX;
> +	writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
> +
> +	/*
> +	 * RTI only supports a windowed mode, where the watchdog can only
> +	 * be petted during the open window; not too early or not too late.
> +	 * The HW configuration options only allow for the open window size
> +	 * to be 50% or less than that; we obviouly want to configure the open
> +	 * window as large as possible so we select the 50% option. To avoid
> +	 * any glitches, we accommodate 5% safety margin also, so we setup
> +	 * the min_hw_hearbeat at 55% of the timeout period.
> +	 */
> +	wdd->min_hw_heartbeat_ms = 11 * wdd->timeout * 1000 / 20;
> +
> +	/* Generate NMI when wdt expires */
> +	writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
> +
> +	/* Open window size 50%; this is the largest window size available */
> +	writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
> +
> +	readl_relaxed(wdt->base + RTIWWDSIZECTRL);
> +
> +	/* enable watchdog */
> +	writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
> +	return 0;
> +}
> +
> +static int rti_wdt_ping(struct watchdog_device *wdd)
> +{
> +	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
> +
> +	/* put watchdog in service state */
> +	writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
> +	/* put watchdog in active state */
> +	writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
> +
> +	return 0;
> +}
> +
> +static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
> +{
> +	u64 timer_counter;
> +	u32 val;
> +	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
> +
> +	/* if timeout has occurred then return 0 */
> +	val = readl_relaxed(wdt->base + RTIWDSTATUS);
> +	if (val & DWDST)
> +		return 0;
> +
> +	timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
> +
> +	do_div(timer_counter, wdt->freq);
> +
> +	return timer_counter;
> +}
> +
> +static const struct watchdog_info rti_wdt_info = {
> +	.options = WDIOF_KEEPALIVEPING,
> +	.identity = "K3 RTI Watchdog",
> +};
> +
> +static const struct watchdog_ops rti_wdt_ops = {
> +	.owner		= THIS_MODULE,
> +	.start		= rti_wdt_start,
> +	.ping		= rti_wdt_ping,
> +	.get_timeleft	= rti_wdt_get_timeleft,
> +};
> +
> +static int rti_wdt_probe(struct platform_device *pdev)
> +{
> +	int ret = 0;
> +	struct device *dev = &pdev->dev;
> +	struct resource *wdt_mem;
> +	struct watchdog_device *wdd;
> +	struct rti_wdt_device *wdt;
> +	struct clk *clk;
> +
> +	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
> +	if (!wdt)
> +		return -ENOMEM;
> +
> +	clk = clk_get(dev, NULL);
> +	if (IS_ERR(clk)) {
> +		if (PTR_ERR(clk) != -EPROBE_DEFER)
> +			dev_err(dev, "failed to get clock\n");
> +		return PTR_ERR(clk);
> +	}
> +
> +	wdt->freq = clk_get_rate(clk);
> +
> +	clk_put(clk);
> +
> +	if (!wdt->freq) {
> +		dev_err(dev, "Failed to get fck rate.\n");
> +		return -EINVAL;
> +	}
> +
> +	pm_runtime_enable(dev);
> +	ret = pm_runtime_get_sync(dev);
> +	if (ret) {
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(&pdev->dev, "runtime pm failed\n");
> +		return ret;
> +	}
> +
> +	platform_set_drvdata(pdev, wdt);
> +
> +	wdd = &wdt->wdd;
> +	wdd->info = &rti_wdt_info;
> +	wdd->ops = &rti_wdt_ops;
> +	wdd->min_timeout = 1;
> +	wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
> +		wdt->freq * 1000;
> +	wdd->timeout = DEFAULT_HEARTBEAT;
> +	wdd->parent = dev;
> +
> +	watchdog_init_timeout(wdd, heartbeat, dev);
> +
> +	watchdog_set_drvdata(wdd, wdt);
> +	watchdog_set_nowayout(wdd, 1);
> +	watchdog_set_restart_priority(wdd, 128);
> +
> +	wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	wdt->base = devm_ioremap_resource(dev, wdt_mem);
> +	if (IS_ERR(wdt->base)) {
> +		ret = PTR_ERR(wdt->base);
> +		goto err_iomap;
> +	}
> +
> +	ret = watchdog_register_device(wdd);
> +	if (ret) {
> +		dev_err(dev, "cannot register watchdog device\n");
> +		goto err_iomap;
> +	}
> +
> +	return 0;
> +
> +err_iomap:
> +	pm_runtime_put_sync(&pdev->dev);
> +
> +	return ret;
> +}
> +
> +static int rti_wdt_remove(struct platform_device *pdev)
> +{
> +	struct rti_wdt_device *wdt = platform_get_drvdata(pdev);
> +
> +	watchdog_unregister_device(&wdt->wdd);
> +	pm_runtime_put(&pdev->dev);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id rti_wdt_of_match[] = {
> +	{ .compatible = "ti,rti-wdt", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, rti_wdt_of_match);
> +
> +static struct platform_driver rti_wdt_driver = {
> +	.driver = {
> +		.name = "rti-wdt",
> +		.of_match_table = rti_wdt_of_match,
> +	},
> +	.probe = rti_wdt_probe,
> +	.remove = rti_wdt_remove,
> +};
> +
> +module_platform_driver(rti_wdt_driver);
> +
> +MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");
> +MODULE_DESCRIPTION("K3 RTI Watchdog Driver");
> +
> +module_param(heartbeat, int, 0);
> +MODULE_PARM_DESC(heartbeat,
> +		 "Watchdog heartbeat period in seconds from 1 to "
> +		 __MODULE_STRING(MAX_HEARTBEAT) ", default "
> +		 __MODULE_STRING(DEFAULT_HEARTBEAT));
> +
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:rti-wdt");
> -- 
> 2.17.1
> 
> --
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

Re: [PATCHv3 3/4] watchdog: Add K3 RTI watchdog support

[Tero Kristo]

On 05/03/2020 00:06, Guenter Roeck wrote:
> On Wed, Mar 04, 2020 at 12:42:14PM +0200, Tero Kristo wrote:
>> Texas Instruments K3 SoCs contain an RTI (Real Time Interrupt) module
>> which can be used as a watchdog. This IP provides a support for
>> windowed watchdog mode, in which the watchdog must be petted within
>> a certain time window. If it is petted either too soon, or too late,
>> a watchdog error will be triggered.
>>
>> Signed-off-by: Tero Kristo <t-kristo@ti.com>
> 
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>

Whats the plan for merging this one + the DT binding doc? I can't see 
this in linux-next yet at least, I do see the watchdog core change from 
this series though.

-Tero

> 
>> ---
>> v3:
>>    * changed to use clk_get/put instead of devm_* versions of this
>>
>> v2:
>>    * Added better documentation within the driver code
>>    * Dropped fck handle, instead get the fck rate during probe only
>>    * Modified the max_hw_heartbeat calculation logic a bit
>>
>>   drivers/watchdog/Kconfig   |   8 ++
>>   drivers/watchdog/Makefile  |   1 +
>>   drivers/watchdog/rti_wdt.c | 255 +++++++++++++++++++++++++++++++++++++
>>   3 files changed, 261 insertions(+)
>>   create mode 100644 drivers/watchdog/rti_wdt.c
>>
>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> index cec868f8db3f..81faf47d44a6 100644
>> --- a/drivers/watchdog/Kconfig
>> +++ b/drivers/watchdog/Kconfig
>> @@ -583,6 +583,14 @@ config DAVINCI_WATCHDOG
>>   	  NOTE: once enabled, this timer cannot be disabled.
>>   	  Say N if you are unsure.
>>   
>> +config K3_RTI_WATCHDOG
>> +	tristate "Texas Instruments K3 RTI watchdog"
>> +	depends on ARCH_K3 || COMPILE_TEST
>> +	select WATCHDOG_CORE
>> +	help
>> +	  Say Y here if you want to include support for the K3 watchdog
>> +	  timer (RTI module) available in the K3 generation of processors.
>> +
>>   config ORION_WATCHDOG
>>   	tristate "Orion watchdog"
>>   	depends on ARCH_ORION5X || ARCH_DOVE || MACH_DOVE || ARCH_MVEBU || (COMPILE_TEST && !ARCH_EBSA110)
>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
>> index 2ee352bf3372..6de2e4ceef19 100644
>> --- a/drivers/watchdog/Makefile
>> +++ b/drivers/watchdog/Makefile
>> @@ -57,6 +57,7 @@ obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
>>   obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
>>   obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
>>   obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
>> +obj-$(CONFIG_K3_RTI_WATCHDOG) += rti_wdt.o
>>   obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
>>   obj-$(CONFIG_SUNXI_WATCHDOG) += sunxi_wdt.o
>>   obj-$(CONFIG_RN5T618_WATCHDOG) += rn5t618_wdt.o
>> diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
>> new file mode 100644
>> index 000000000000..7a46c40891e2
>> --- /dev/null
>> +++ b/drivers/watchdog/rti_wdt.c
>> @@ -0,0 +1,255 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Watchdog driver for the K3 RTI module
>> + *
>> + * (c) Copyright 2019-2020 Texas Instruments Inc.
>> + * All rights reserved.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/device.h>
>> +#include <linux/err.h>
>> +#include <linux/io.h>
>> +#include <linux/kernel.h>
>> +#include <linux/mod_devicetable.h>
>> +#include <linux/module.h>
>> +#include <linux/moduleparam.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/types.h>
>> +#include <linux/watchdog.h>
>> +
>> +#define DEFAULT_HEARTBEAT 60
>> +
>> +/* Max heartbeat is calculated at 32kHz source clock */
>> +#define MAX_HEARTBEAT	1000
>> +
>> +/* Timer register set definition */
>> +#define RTIDWDCTRL	0x90
>> +#define RTIDWDPRLD	0x94
>> +#define RTIWDSTATUS	0x98
>> +#define RTIWDKEY	0x9c
>> +#define RTIDWDCNTR	0xa0
>> +#define RTIWWDRXCTRL	0xa4
>> +#define RTIWWDSIZECTRL	0xa8
>> +
>> +#define RTIWWDRX_NMI	0xa
>> +
>> +#define RTIWWDSIZE_50P	0x50
>> +
>> +#define WDENABLE_KEY	0xa98559da
>> +
>> +#define WDKEY_SEQ0		0xe51a
>> +#define WDKEY_SEQ1		0xa35c
>> +
>> +#define WDT_PRELOAD_SHIFT	13
>> +
>> +#define WDT_PRELOAD_MAX		0xfff
>> +
>> +#define DWDST			BIT(1)
>> +
>> +static int heartbeat;
>> +
>> +/*
>> + * struct to hold data for each WDT device
>> + * @base - base io address of WD device
>> + * @freq - source clock frequency of WDT
>> + * @wdd  - hold watchdog device as is in WDT core
>> + */
>> +struct rti_wdt_device {
>> +	void __iomem		*base;
>> +	unsigned long		freq;
>> +	struct watchdog_device	wdd;
>> +};
>> +
>> +static int rti_wdt_start(struct watchdog_device *wdd)
>> +{
>> +	u32 timer_margin;
>> +	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
>> +
>> +	/* set timeout period */
>> +	timer_margin = (u64)wdd->timeout * wdt->freq;
>> +	timer_margin >>= WDT_PRELOAD_SHIFT;
>> +	if (timer_margin > WDT_PRELOAD_MAX)
>> +		timer_margin = WDT_PRELOAD_MAX;
>> +	writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
>> +
>> +	/*
>> +	 * RTI only supports a windowed mode, where the watchdog can only
>> +	 * be petted during the open window; not too early or not too late.
>> +	 * The HW configuration options only allow for the open window size
>> +	 * to be 50% or less than that; we obviouly want to configure the open
>> +	 * window as large as possible so we select the 50% option. To avoid
>> +	 * any glitches, we accommodate 5% safety margin also, so we setup
>> +	 * the min_hw_hearbeat at 55% of the timeout period.
>> +	 */
>> +	wdd->min_hw_heartbeat_ms = 11 * wdd->timeout * 1000 / 20;
>> +
>> +	/* Generate NMI when wdt expires */
>> +	writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
>> +
>> +	/* Open window size 50%; this is the largest window size available */
>> +	writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
>> +
>> +	readl_relaxed(wdt->base + RTIWWDSIZECTRL);
>> +
>> +	/* enable watchdog */
>> +	writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
>> +	return 0;
>> +}
>> +
>> +static int rti_wdt_ping(struct watchdog_device *wdd)
>> +{
>> +	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
>> +
>> +	/* put watchdog in service state */
>> +	writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
>> +	/* put watchdog in active state */
>> +	writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
>> +
>> +	return 0;
>> +}
>> +
>> +static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
>> +{
>> +	u64 timer_counter;
>> +	u32 val;
>> +	struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
>> +
>> +	/* if timeout has occurred then return 0 */
>> +	val = readl_relaxed(wdt->base + RTIWDSTATUS);
>> +	if (val & DWDST)
>> +		return 0;
>> +
>> +	timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
>> +
>> +	do_div(timer_counter, wdt->freq);
>> +
>> +	return timer_counter;
>> +}
>> +
>> +static const struct watchdog_info rti_wdt_info = {
>> +	.options = WDIOF_KEEPALIVEPING,
>> +	.identity = "K3 RTI Watchdog",
>> +};
>> +
>> +static const struct watchdog_ops rti_wdt_ops = {
>> +	.owner		= THIS_MODULE,
>> +	.start		= rti_wdt_start,
>> +	.ping		= rti_wdt_ping,
>> +	.get_timeleft	= rti_wdt_get_timeleft,
>> +};
>> +
>> +static int rti_wdt_probe(struct platform_device *pdev)
>> +{
>> +	int ret = 0;
>> +	struct device *dev = &pdev->dev;
>> +	struct resource *wdt_mem;
>> +	struct watchdog_device *wdd;
>> +	struct rti_wdt_device *wdt;
>> +	struct clk *clk;
>> +
>> +	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
>> +	if (!wdt)
>> +		return -ENOMEM;
>> +
>> +	clk = clk_get(dev, NULL);
>> +	if (IS_ERR(clk)) {
>> +		if (PTR_ERR(clk) != -EPROBE_DEFER)
>> +			dev_err(dev, "failed to get clock\n");
>> +		return PTR_ERR(clk);
>> +	}
>> +
>> +	wdt->freq = clk_get_rate(clk);
>> +
>> +	clk_put(clk);
>> +
>> +	if (!wdt->freq) {
>> +		dev_err(dev, "Failed to get fck rate.\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	pm_runtime_enable(dev);
>> +	ret = pm_runtime_get_sync(dev);
>> +	if (ret) {
>> +		if (ret != -EPROBE_DEFER)
>> +			dev_err(&pdev->dev, "runtime pm failed\n");
>> +		return ret;
>> +	}
>> +
>> +	platform_set_drvdata(pdev, wdt);
>> +
>> +	wdd = &wdt->wdd;
>> +	wdd->info = &rti_wdt_info;
>> +	wdd->ops = &rti_wdt_ops;
>> +	wdd->min_timeout = 1;
>> +	wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
>> +		wdt->freq * 1000;
>> +	wdd->timeout = DEFAULT_HEARTBEAT;
>> +	wdd->parent = dev;
>> +
>> +	watchdog_init_timeout(wdd, heartbeat, dev);
>> +
>> +	watchdog_set_drvdata(wdd, wdt);
>> +	watchdog_set_nowayout(wdd, 1);
>> +	watchdog_set_restart_priority(wdd, 128);
>> +
>> +	wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	wdt->base = devm_ioremap_resource(dev, wdt_mem);
>> +	if (IS_ERR(wdt->base)) {
>> +		ret = PTR_ERR(wdt->base);
>> +		goto err_iomap;
>> +	}
>> +
>> +	ret = watchdog_register_device(wdd);
>> +	if (ret) {
>> +		dev_err(dev, "cannot register watchdog device\n");
>> +		goto err_iomap;
>> +	}
>> +
>> +	return 0;
>> +
>> +err_iomap:
>> +	pm_runtime_put_sync(&pdev->dev);
>> +
>> +	return ret;
>> +}
>> +
>> +static int rti_wdt_remove(struct platform_device *pdev)
>> +{
>> +	struct rti_wdt_device *wdt = platform_get_drvdata(pdev);
>> +
>> +	watchdog_unregister_device(&wdt->wdd);
>> +	pm_runtime_put(&pdev->dev);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id rti_wdt_of_match[] = {
>> +	{ .compatible = "ti,rti-wdt", },
>> +	{},
>> +};
>> +MODULE_DEVICE_TABLE(of, rti_wdt_of_match);
>> +
>> +static struct platform_driver rti_wdt_driver = {
>> +	.driver = {
>> +		.name = "rti-wdt",
>> +		.of_match_table = rti_wdt_of_match,
>> +	},
>> +	.probe = rti_wdt_probe,
>> +	.remove = rti_wdt_remove,
>> +};
>> +
>> +module_platform_driver(rti_wdt_driver);
>> +
>> +MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");
>> +MODULE_DESCRIPTION("K3 RTI Watchdog Driver");
>> +
>> +module_param(heartbeat, int, 0);
>> +MODULE_PARM_DESC(heartbeat,
>> +		 "Watchdog heartbeat period in seconds from 1 to "
>> +		 __MODULE_STRING(MAX_HEARTBEAT) ", default "
>> +		 __MODULE_STRING(DEFAULT_HEARTBEAT));
>> +
>> +MODULE_LICENSE("GPL");
>> +MODULE_ALIAS("platform:rti-wdt");
>> -- 
>> 2.17.1
>>
>> --

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Re: [PATCHv3 3/4] watchdog: Add K3 RTI watchdog support

[Guenter Roeck]

On 4/1/20 5:44 AM, Tero Kristo wrote:
> On 05/03/2020 00:06, Guenter Roeck wrote:
>> On Wed, Mar 04, 2020 at 12:42:14PM +0200, Tero Kristo wrote:
>>> Texas Instruments K3 SoCs contain an RTI (Real Time Interrupt) module
>>> which can be used as a watchdog. This IP provides a support for
>>> windowed watchdog mode, in which the watchdog must be petted within
>>> a certain time window. If it is petted either too soon, or too late,
>>> a watchdog error will be triggered.
>>>
>>> Signed-off-by: Tero Kristo <t-kristo@ti.com>
>>
>> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> 
> Whats the plan for merging this one + the DT binding doc? I can't see this in linux-next yet at least, I do see the watchdog core change from this series though.
> 

It is in my watchdog-next branch at
git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git.

Wim usually picks it up from there.

The core patch didn't depend on DT approval, so I (and Wim) picked it up
earlier.

Guenter

Re: [PATCHv3 3/4] watchdog: Add K3 RTI watchdog support

[Tero Kristo]

On 01/04/2020 18:55, Guenter Roeck wrote:
> On 4/1/20 5:44 AM, Tero Kristo wrote:
>> On 05/03/2020 00:06, Guenter Roeck wrote:
>>> On Wed, Mar 04, 2020 at 12:42:14PM +0200, Tero Kristo wrote:
>>>> Texas Instruments K3 SoCs contain an RTI (Real Time Interrupt) module
>>>> which can be used as a watchdog. This IP provides a support for
>>>> windowed watchdog mode, in which the watchdog must be petted within
>>>> a certain time window. If it is petted either too soon, or too late,
>>>> a watchdog error will be triggered.
>>>>
>>>> Signed-off-by: Tero Kristo <t-kristo@ti.com>
>>>
>>> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
>>
>> Whats the plan for merging this one + the DT binding doc? I can't see this in linux-next yet at least, I do see the watchdog core change from this series though.
>>
> 
> It is in my watchdog-next branch at
> git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git.
> 
> Wim usually picks it up from there.
> 
> The core patch didn't depend on DT approval, so I (and Wim) picked it up
> earlier.

Ok thanks for clarification, I thought there was something like that 
going in the background but decided to double check.

-Tero
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Re: [PATCHv2 3/4] watchdog: Add K3 RTI watchdog support

[Tero Kristo]

On 04/03/2020 11:23, Guenter Roeck wrote:
> On 3/3/20 10:57 PM, Tero Kristo wrote:
>> On 03/03/2020 23:18, Guenter Roeck wrote:
>>> On Mon, Mar 02, 2020 at 10:04:25PM +0200, Tero Kristo wrote:
>>>> Texas Instruments K3 SoCs contain an RTI (Real Time Interrupt) module
>>>> which can be used as a watchdog. This IP provides a support for
>>>> windowed watchdog mode, in which the watchdog must be petted within
>>>> a certain time window. If it is petted either too soon, or too late,
>>>> a watchdog error will be triggered.
>>>>
>>>> Signed-off-by: Tero Kristo <t-kristo@ti.com>
>>>> ---
>>>> v2:
>>>>     * Added better documentation within the driver code
>>>>     * Dropped fck handle, instead get the fck rate during probe only
>>>>     * Modified the max_hw_heartbeat calculation logic a bit
>>>>
>>>>    drivers/watchdog/Kconfig   |   8 ++
>>>>    drivers/watchdog/Makefile  |   1 +
>>>>    drivers/watchdog/rti_wdt.c | 254 +++++++++++++++++++++++++++++++++++++
>>>>    3 files changed, 261 insertions(+)
>>>>    create mode 100644 drivers/watchdog/rti_wdt.c
>>>>
>>>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>>>> index cec868f8db3f..81faf47d44a6 100644
>>>> --- a/drivers/watchdog/Kconfig
>>>> +++ b/drivers/watchdog/Kconfig
>>>> @@ -583,6 +583,14 @@ config DAVINCI_WATCHDOG
>>>>          NOTE: once enabled, this timer cannot be disabled.
>>>>          Say N if you are unsure.
>>>>    +config K3_RTI_WATCHDOG
>>>> +    tristate "Texas Instruments K3 RTI watchdog"
>>>> +    depends on ARCH_K3 || COMPILE_TEST
>>>> +    select WATCHDOG_CORE
>>>> +    help
>>>> +      Say Y here if you want to include support for the K3 watchdog
>>>> +      timer (RTI module) available in the K3 generation of processors.
>>>> +
>>>>    config ORION_WATCHDOG
>>>>        tristate "Orion watchdog"
>>>>        depends on ARCH_ORION5X || ARCH_DOVE || MACH_DOVE || ARCH_MVEBU || (COMPILE_TEST && !ARCH_EBSA110)
>>>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
>>>> index 2ee352bf3372..6de2e4ceef19 100644
>>>> --- a/drivers/watchdog/Makefile
>>>> +++ b/drivers/watchdog/Makefile
>>>> @@ -57,6 +57,7 @@ obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
>>>>    obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
>>>>    obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
>>>>    obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
>>>> +obj-$(CONFIG_K3_RTI_WATCHDOG) += rti_wdt.o
>>>>    obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
>>>>    obj-$(CONFIG_SUNXI_WATCHDOG) += sunxi_wdt.o
>>>>    obj-$(CONFIG_RN5T618_WATCHDOG) += rn5t618_wdt.o
>>>> diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
>>>> new file mode 100644
>>>> index 000000000000..7a46c40891e2
>>>> --- /dev/null
>>>> +++ b/drivers/watchdog/rti_wdt.c
>>>> @@ -0,0 +1,254 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +/*
>>>> + * Watchdog driver for the K3 RTI module
>>>> + *
>>>> + * (c) Copyright 2019-2020 Texas Instruments Inc.
>>>> + * All rights reserved.
>>>> + */
>>>> +
>>>> +#include <linux/clk.h>
>>>> +#include <linux/device.h>
>>>> +#include <linux/err.h>
>>>> +#include <linux/io.h>
>>>> +#include <linux/kernel.h>
>>>> +#include <linux/mod_devicetable.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/moduleparam.h>
>>>> +#include <linux/platform_device.h>
>>>> +#include <linux/pm_runtime.h>
>>>> +#include <linux/types.h>
>>>> +#include <linux/watchdog.h>
>>>> +
>>>> +#define DEFAULT_HEARTBEAT 60
>>>> +
>>>> +/* Max heartbeat is calculated at 32kHz source clock */
>>>> +#define MAX_HEARTBEAT    1000
>>>> +
>>>> +/* Timer register set definition */
>>>> +#define RTIDWDCTRL    0x90
>>>> +#define RTIDWDPRLD    0x94
>>>> +#define RTIWDSTATUS    0x98
>>>> +#define RTIWDKEY    0x9c
>>>> +#define RTIDWDCNTR    0xa0
>>>> +#define RTIWWDRXCTRL    0xa4
>>>> +#define RTIWWDSIZECTRL    0xa8
>>>> +
>>>> +#define RTIWWDRX_NMI    0xa
>>>> +
>>>> +#define RTIWWDSIZE_50P    0x50
>>>> +
>>>> +#define WDENABLE_KEY    0xa98559da
>>>> +
>>>> +#define WDKEY_SEQ0        0xe51a
>>>> +#define WDKEY_SEQ1        0xa35c
>>>> +
>>>> +#define WDT_PRELOAD_SHIFT    13
>>>> +
>>>> +#define WDT_PRELOAD_MAX        0xfff
>>>> +
>>>> +#define DWDST            BIT(1)
>>>> +
>>>> +static int heartbeat;
>>>> +
>>>> +/*
>>>> + * struct to hold data for each WDT device
>>>> + * @base - base io address of WD device
>>>> + * @freq - source clock frequency of WDT
>>>> + * @wdd  - hold watchdog device as is in WDT core
>>>> + */
>>>> +struct rti_wdt_device {
>>>> +    void __iomem        *base;
>>>> +    unsigned long        freq;
>>>> +    struct watchdog_device    wdd;
>>>> +};
>>>> +
>>>> +static int rti_wdt_start(struct watchdog_device *wdd)
>>>> +{
>>>> +    u32 timer_margin;
>>>> +    struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
>>>> +
>>>> +    /* set timeout period */
>>>> +    timer_margin = (u64)wdd->timeout * wdt->freq;
>>>> +    timer_margin >>= WDT_PRELOAD_SHIFT;
>>>> +    if (timer_margin > WDT_PRELOAD_MAX)
>>>> +        timer_margin = WDT_PRELOAD_MAX;
>>>> +    writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
>>>> +
>>>> +    /*
>>>> +     * RTI only supports a windowed mode, where the watchdog can only
>>>> +     * be petted during the open window; not too early or not too late.
>>>> +     * The HW configuration options only allow for the open window size
>>>> +     * to be 50% or less than that; we obviouly want to configure the open
>>>> +     * window as large as possible so we select the 50% option. To avoid
>>>> +     * any glitches, we accommodate 5% safety margin also, so we setup
>>>> +     * the min_hw_hearbeat at 55% of the timeout period.
>>>> +     */
>>>> +    wdd->min_hw_heartbeat_ms = 11 * wdd->timeout * 1000 / 20;
>>>> +
>>>> +    /* Generate NMI when wdt expires */
>>>> +    writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
>>>> +
>>>> +    /* Open window size 50%; this is the largest window size available */
>>>> +    writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
>>>> +
>>>> +    readl_relaxed(wdt->base + RTIWWDSIZECTRL);
>>>> +
>>>> +    /* enable watchdog */
>>>> +    writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int rti_wdt_ping(struct watchdog_device *wdd)
>>>> +{
>>>> +    struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
>>>> +
>>>> +    /* put watchdog in service state */
>>>> +    writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
>>>> +    /* put watchdog in active state */
>>>> +    writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
>>>> +{
>>>> +    u64 timer_counter;
>>>> +    u32 val;
>>>> +    struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
>>>> +
>>>> +    /* if timeout has occurred then return 0 */
>>>> +    val = readl_relaxed(wdt->base + RTIWDSTATUS);
>>>> +    if (val & DWDST)
>>>> +        return 0;
>>>> +
>>>> +    timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
>>>> +
>>>> +    do_div(timer_counter, wdt->freq);
>>>> +
>>>> +    return timer_counter;
>>>> +}
>>>> +
>>>> +static const struct watchdog_info rti_wdt_info = {
>>>> +    .options = WDIOF_KEEPALIVEPING,
>>>> +    .identity = "K3 RTI Watchdog",
>>>> +};
>>>> +
>>>> +static const struct watchdog_ops rti_wdt_ops = {
>>>> +    .owner        = THIS_MODULE,
>>>> +    .start        = rti_wdt_start,
>>>> +    .ping        = rti_wdt_ping,
>>>> +    .get_timeleft    = rti_wdt_get_timeleft,
>>>> +};
>>>> +
>>>> +static int rti_wdt_probe(struct platform_device *pdev)
>>>> +{
>>>> +    int ret = 0;
>>>> +    struct device *dev = &pdev->dev;
>>>> +    struct resource *wdt_mem;
>>>> +    struct watchdog_device *wdd;
>>>> +    struct rti_wdt_device *wdt;
>>>> +    struct clk *clk;
>>>> +
>>>> +    wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
>>>> +    if (!wdt)
>>>> +        return -ENOMEM;
>>>> +
>>>> +    clk = devm_clk_get(dev, NULL);
>>>> +    if (IS_ERR(clk)) {
>>>> +        if (PTR_ERR(clk) != -EPROBE_DEFER)
>>>> +            dev_err(dev, "failed to get clock\n");
>>>> +        return PTR_ERR(clk);
>>>> +    }
>>>> +
>>>> +    wdt->freq = clk_get_rate(clk);
>>>> +    if (!wdt->freq) {
>>>> +        dev_err(dev, "Failed to get fck rate.\n");
>>>> +        return -EINVAL;
>>>> +    }
>>>> +
>>>> +    devm_clk_put(dev, clk);
>>>> +
>>> Are you sure about this ? Doesn't this mean that the clock may be stopped ?
>>> Normally the reason for using devm_ functions during probe is that release
>>> functions are called automatically when the device is removed. Calling
>>> the release function dorectly is unusual and most of the time wrong.
>>
>> clk_get / clk_put does not enable / disable a clock by itself, this is just used to fetch a clock handle. But you are right, we are never calling clk_enable on it either, because at least the 32kHz clock we are interested in is of type always-on and can never be disabled.
>>
>> I can keep the clock handle and call enable/disable on it in the probe/remove if you think that would be neater.
>>
> 
> If it isn't needed to be held, you should use clk_get / clk_put,
> and not the devm_ functions.

Ok, changed this and posted v3 of patch #3 only.

-Tero

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[PATCHv2 4/4] arm64: dts: ti: k3-j721e-main: Add MAIN domain watchdog entries

[Tero Kristo]

Add DT entries for main domain watchdog0 and 1 instances.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
---
 arch/arm64/boot/dts/ti/k3-j721e-main.dtsi | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-j721e-main.dtsi b/arch/arm64/boot/dts/ti/k3-j721e-main.dtsi
index 0b9d14b838a1..7ab989496c2c 100644
--- a/arch/arm64/boot/dts/ti/k3-j721e-main.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-j721e-main.dtsi
@@ -963,4 +963,22 @@
 
 		status = "disabled";
 	};
+
+	main_rti0: rti@2200000 {
+		compatible = "ti,rti-wdt";
+		reg = <0x0 0x2200000 0x0 0x100>;
+		clocks = <&k3_clks 252 1>;
+		power-domains = <&k3_pds 252 TI_SCI_PD_EXCLUSIVE>;
+		assigned-clocks = <&k3_clks 252 1>;
+		assigned-clock-parents = <&k3_clks 252 5>;
+	};
+
+	main_rti1: rti@2210000 {
+		compatible = "ti,rti-wdt";
+		reg = <0x0 0x2210000 0x0 0x100>;
+		clocks = <&k3_clks 253 1>;
+		power-domains = <&k3_pds 253 TI_SCI_PD_EXCLUSIVE>;
+		assigned-clocks = <&k3_clks 253 1>;
+		assigned-clock-parents = <&k3_clks 253 5>;
+	};
 };
-- 
2.17.1

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