[PATCH V9, RESEND, 0/2] watchdog: mtk: support pre-timeout when the bark irq is available

[PATCH V9, RESEND, 0/2] watchdog: mtk: support pre-timeout when the bark irq is available

[Wang Qing]

Use the bark interrupt as the pretimeout notifier if available.
The pretimeout notification shall occur at timeout-sec/2.

Wang Qing (2):
  watchdog: mtk: support pre-timeout when the bark irq is available
  doc: mtk-wdt: support pre-timeout when the bark irq is available

 .../devicetree/bindings/watchdog/mtk-wdt.txt       |  5 ++
 drivers/watchdog/mtk_wdt.c                         | 77 ++++++++++++++++++++--
 2 files changed, 77 insertions(+), 5 deletions(-)

-- 
2.7.4


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[PATCH V9, RESEND, 1/2] watchdog: mtk: support pre-timeout when the bark irq is available

[Wang Qing]

Use the bark interrupt as the pretimeout notifier if available.

When the watchdog timer expires in dual mode, an interrupt will be
triggered first, then the timing restarts. The reset signal will be
initiated when the timer expires again.

The pretimeout notification shall occur at timeout-sec/2.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wang Qing <wangqing@vivo.com>
---
 drivers/watchdog/mtk_wdt.c | 77 +++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 72 insertions(+), 5 deletions(-)

diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
index 97ca993..7bb0774
--- a/drivers/watchdog/mtk_wdt.c
+++ b/drivers/watchdog/mtk_wdt.c
@@ -25,9 +25,10 @@
 #include <linux/reset-controller.h>
 #include <linux/types.h>
 #include <linux/watchdog.h>
+#include <linux/interrupt.h>
 
 #define WDT_MAX_TIMEOUT		31
-#define WDT_MIN_TIMEOUT		1
+#define WDT_MIN_TIMEOUT		2
 #define WDT_LENGTH_TIMEOUT(n)	((n) << 5)
 
 #define WDT_LENGTH		0x04
@@ -187,12 +188,19 @@ static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
 	u32 reg;
 
 	wdt_dev->timeout = timeout;
+	/*
+	 * In dual mode, irq will be triggered at timeout / 2
+	 * the real timeout occurs at timeout
+	 */
+	if (wdt_dev->pretimeout)
+		wdt_dev->pretimeout = timeout / 2;
 
 	/*
 	 * One bit is the value of 512 ticks
 	 * The clock has 32 KHz
 	 */
-	reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY;
+	reg = WDT_LENGTH_TIMEOUT((timeout - wdt_dev->pretimeout) << 6)
+			| WDT_LENGTH_KEY;
 	iowrite32(reg, wdt_base + WDT_LENGTH);
 
 	mtk_wdt_ping(wdt_dev);
@@ -239,13 +247,48 @@ static int mtk_wdt_start(struct watchdog_device *wdt_dev)
 		return ret;
 
 	reg = ioread32(wdt_base + WDT_MODE);
-	reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
+	if (wdt_dev->pretimeout)
+		reg |= (WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
+	else
+		reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
 	reg |= (WDT_MODE_EN | WDT_MODE_KEY);
 	iowrite32(reg, wdt_base + WDT_MODE);
 
 	return 0;
 }
 
+static int mtk_wdt_set_pretimeout(struct watchdog_device *wdd,
+				  unsigned int timeout)
+{
+	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdd);
+	void __iomem *wdt_base = mtk_wdt->wdt_base;
+	u32 reg = ioread32(wdt_base + WDT_MODE);
+
+	if (timeout && !wdd->pretimeout) {
+		wdd->pretimeout = wdd->timeout / 2;
+		reg |= (WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
+	} else if (!timeout && wdd->pretimeout) {
+		wdd->pretimeout = 0;
+		reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
+	} else {
+		return 0;
+	}
+
+	reg |= WDT_MODE_KEY;
+	iowrite32(reg, wdt_base + WDT_MODE);
+
+	return mtk_wdt_set_timeout(wdd, wdd->timeout);
+}
+
+static irqreturn_t mtk_wdt_isr(int irq, void *arg)
+{
+	struct watchdog_device *wdd = arg;
+
+	watchdog_notify_pretimeout(wdd);
+
+	return IRQ_HANDLED;
+}
+
 static const struct watchdog_info mtk_wdt_info = {
 	.identity	= DRV_NAME,
 	.options	= WDIOF_SETTIMEOUT |
@@ -253,12 +296,21 @@ static const struct watchdog_info mtk_wdt_info = {
 			  WDIOF_MAGICCLOSE,
 };
 
+static const struct watchdog_info mtk_wdt_pt_info = {
+	.identity	= DRV_NAME,
+	.options	= WDIOF_SETTIMEOUT |
+			  WDIOF_PRETIMEOUT |
+			  WDIOF_KEEPALIVEPING |
+			  WDIOF_MAGICCLOSE,
+};
+
 static const struct watchdog_ops mtk_wdt_ops = {
 	.owner		= THIS_MODULE,
 	.start		= mtk_wdt_start,
 	.stop		= mtk_wdt_stop,
 	.ping		= mtk_wdt_ping,
 	.set_timeout	= mtk_wdt_set_timeout,
+	.set_pretimeout	= mtk_wdt_set_pretimeout,
 	.restart	= mtk_wdt_restart,
 };
 
@@ -267,7 +319,7 @@ static int mtk_wdt_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct mtk_wdt_dev *mtk_wdt;
 	const struct mtk_wdt_data *wdt_data;
-	int err;
+	int err, irq;
 
 	mtk_wdt = devm_kzalloc(dev, sizeof(*mtk_wdt), GFP_KERNEL);
 	if (!mtk_wdt)
@@ -279,7 +331,22 @@ static int mtk_wdt_probe(struct platform_device *pdev)
 	if (IS_ERR(mtk_wdt->wdt_base))
 		return PTR_ERR(mtk_wdt->wdt_base);
 
-	mtk_wdt->wdt_dev.info = &mtk_wdt_info;
+	irq = platform_get_irq(pdev, 0);
+	if (irq > 0) {
+		err = devm_request_irq(&pdev->dev, irq, mtk_wdt_isr, 0, "wdt_bark",
+				       &mtk_wdt->wdt_dev);
+		if (err)
+			return err;
+
+		mtk_wdt->wdt_dev.info = &mtk_wdt_pt_info;
+		mtk_wdt->wdt_dev.pretimeout = WDT_MAX_TIMEOUT / 2;
+	} else {
+		if (irq == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+
+		mtk_wdt->wdt_dev.info = &mtk_wdt_info;
+	}
+
 	mtk_wdt->wdt_dev.ops = &mtk_wdt_ops;
 	mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
 	mtk_wdt->wdt_dev.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT * 1000;
-- 
2.7.4


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[PATCH V9, RESEND, 2/2] doc: mtk-wdt: support pre-timeout when the bark irq is available

[Wang Qing]

Add description of pre-timeout in mtk-wdt.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wang Qing <wangqing@vivo.com>
---
 Documentation/devicetree/bindings/watchdog/mtk-wdt.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
index e36ba60..8e27777
--- a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
+++ b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
@@ -1,5 +1,8 @@
 Mediatek SoCs Watchdog timer
 
+The watchdog supports a pre-timeout interrupt that fires timeout-sec/2
+before the expiry.
+
 Required properties:
 
 - compatible should contain:
@@ -17,6 +20,7 @@ Required properties:
 - reg : Specifies base physical address and size of the registers.
 
 Optional properties:
+- interrupts: Watchdog pre-timeout (bark) interrupt.
 - timeout-sec: contains the watchdog timeout in seconds.
 - #reset-cells: Should be 1.
 
@@ -26,6 +30,7 @@ watchdog: watchdog@10007000 {
 	compatible = "mediatek,mt8183-wdt",
 		     "mediatek,mt6589-wdt";
 	reg = <0 0x10007000 0 0x100>;
+	interrupts = <GIC_SPI 139 IRQ_TYPE_NONE>;
 	timeout-sec = <10>;
 	#reset-cells = <1>;
 };
-- 
2.7.4


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Re: [PATCH V9,RESEND,0/2] watchdog: mtk: support pre-timeout when the bark irq is available

[Guenter Roeck]

On Mon, May 31, 2021 at 09:51:33AM +0800, Wang Qing wrote:
> Use the bark interrupt as the pretimeout notifier if available.
> The pretimeout notification shall occur at timeout-sec/2.
> 
> Wang Qing (2):
>   watchdog: mtk: support pre-timeout when the bark irq is available
>   doc: mtk-wdt: support pre-timeout when the bark irq is available
> 
>  .../devicetree/bindings/watchdog/mtk-wdt.txt       |  5 ++
>  drivers/watchdog/mtk_wdt.c                         | 77 ++++++++++++++++++++--
>  2 files changed, 77 insertions(+), 5 deletions(-)
> 

The series is already included in my watchdog-next branch, making this just
noise. On top of that, it is v2 without change log, meaning I have no idea
what changed since v1 and if it is different to the version I queued.
If it wasn't queued already, you'd get a message telling you to resubmit
with change log. As it is, I'll keep my version and drop this one.
Wim to decide what to do with it.

Guenter

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