Date: Tue, 3 Nov 2015 16:04:48 +0800
From: Robin Gong <b38343@freescale.com>
To: Guenter Roeck <linux@roeck-us.net>
CC: <wim@iguana.be>, <linux-watchdog@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2 2/2] watchdog: imx2_wdt: add set_pretimeout interface
Message-ID: <20151103080447.GB15428@shlinux2>
References: <1446531084-15365-1-git-send-email-b38343@freescale.com>
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 <563866CD.1080306@roeck-us.net>
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On Mon, Nov 02, 2015 at 11:48:29PM -0800, Guenter Roeck wrote:
> On 11/02/2015 10:11 PM, Robin Gong wrote:
> >Enable set_pretimeout interface and trigger the pretimeout interrupt before
> >watchdog timeout event happen.
> >
> >Signed-off-by: Robin Gong <b38343@freescale.com>
> >---
> >  drivers/watchdog/imx2_wdt.c | 58 ++++++++++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 57 insertions(+), 1 deletion(-)
> >
> >diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
> >index 0bb1a1d..bd42857 100644
> >--- a/drivers/watchdog/imx2_wdt.c
> >+++ b/drivers/watchdog/imx2_wdt.c
> >@@ -24,6 +24,7 @@
> >  #include <linux/clk.h>
> >  #include <linux/delay.h>
> >  #include <linux/init.h>
> >+#include <linux/interrupt.h>
> >  #include <linux/io.h>
> >  #include <linux/jiffies.h>
> >  #include <linux/kernel.h>
> >@@ -52,12 +53,18 @@
> >  #define IMX2_WDT_WRSR		0x04		/* Reset Status Register */
> >  #define IMX2_WDT_WRSR_TOUT	(1 << 1)	/* -> Reset due to Timeout */
> >
> >+#define IMX2_WDT_WICR		0x06		/*Interrupt Control Register*/
> >+#define IMX2_WDT_WICR_WIE	(1 << 15)	/* -> Interrupt Enable */
> >+#define IMX2_WDT_WICR_WTIS	(1 << 14)	/* -> Interrupt Status */
> >+#define IMX2_WDT_WICR_WICT	(0xFF)	/* Watchdog Interrupt Timeout */
> 
> Unnecessary ( )
> 
> >+
> >  #define IMX2_WDT_WMCR		0x08		/* Misc Register */
> >
> >  #define IMX2_WDT_MAX_TIME	128
> >  #define IMX2_WDT_DEFAULT_TIME	60		/* in seconds */
> >
> >  #define WDOG_SEC_TO_COUNT(s)	((s * 2 - 1) << 8)
> >+#define WDOG_SEC_TO_PRECOUNT(s)	((s) * 2)	/* set WDOG pre timeout count*/
> >
> >  struct imx2_wdt_device {
> >  	struct clk *clk;
> >@@ -80,7 +87,8 @@ MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
> >
> >  static const struct watchdog_info imx2_wdt_info = {
> >  	.identity = "imx2+ watchdog",
> >-	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
> >+	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
> >+		   | WDIOF_PRETIMEOUT,
> >  };
> >
> >  static int imx2_restart_handler(struct notifier_block *this, unsigned long mode,
> >@@ -207,12 +215,49 @@ static inline void imx2_wdt_ping_if_active(struct watchdog_device *wdog)
> >  	}
> >  }
> >
> >+static int imx2_wdt_set_pretimeout(struct watchdog_device *wdog,
> >+				   unsigned int new_timeout)
> >+{
> >+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
> >+	u32 val;
> >+
> >+	regmap_read(wdev->regmap, IMX2_WDT_WICR, &val);
> >+	/* set the new pre-timeout value in the WSR */
> >+	val &= ~IMX2_WDT_WICR_WICT;
> >+	val |= WDOG_SEC_TO_PRECOUNT(new_timeout);
> 
> Looking into this, I think we need more information in the first patch.
> Specifically, we need a value for max_pretimeout and validate it
> (new_timeout must be smaller than 128 to avoid overflows, independent
> of the maximum timeout).
>
I think it's enough, since there is "t >= wdd->timeout" in
watchdog_pretimeout_invalid() of the first patch and wdd->timeout is never
bigger than wdd->max_timeout which setting in imx2_wdt.c as 128.
> >+
> >+	regmap_write(wdev->regmap, IMX2_WDT_WICR, val | IMX2_WDT_WICR_WIE);
> >+
> >+	wdog->pretimeout = new_timeout;
> >+
> >+	return 0;
> >+}
> >+
> >+static irqreturn_t imx2_wdt_isr(int irq, void *dev_id)
> >+{
> >+	struct platform_device *pdev = dev_id;
> >+	struct watchdog_device *wdog = platform_get_drvdata(pdev);
> >+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
> >+	u32 val;
> >+
> >+	regmap_read(wdev->regmap, IMX2_WDT_WICR, &val);
> >+	if (val & IMX2_WDT_WICR_WTIS) {
> >+		/*clear interrupt status bit*/
> >+		regmap_write(wdev->regmap, IMX2_WDT_WICR, val);
> >+		panic("pre-timeout:%d, %d Seconds remained\n", wdog->pretimeout,
> 
> "seconds" - no capital 'S'.
> 
> >+		      wdog->timeout - wdog->pretimeout);
> >+	}
> >+
> >+	return IRQ_HANDLED;
> >+}
> >+
> >  static const struct watchdog_ops imx2_wdt_ops = {
> >  	.owner = THIS_MODULE,
> >  	.start = imx2_wdt_start,
> >  	.stop = imx2_wdt_stop,
> >  	.ping = imx2_wdt_ping,
> >  	.set_timeout = imx2_wdt_set_timeout,
> >+	.set_pretimeout = imx2_wdt_set_pretimeout,
> >  };
> >
> >  static const struct regmap_config imx2_wdt_regmap_config = {
> >@@ -229,6 +274,7 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
> >  	struct resource *res;
> >  	void __iomem *base;
> >  	int ret;
> >+	int irq;
> >  	u32 val;
> >
> >  	wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
> >@@ -294,6 +340,16 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
> >  		goto disable_clk;
> >  	}
> >
> >+	irq = platform_get_irq(pdev, 0);
> >+	if (irq > 0) {
> >+		ret = devm_request_irq(&pdev->dev, irq, imx2_wdt_isr, 0,
> >+				       dev_name(&pdev->dev), pdev);
> >+		if (ret) {
> >+			dev_err(&pdev->dev, "can't get irq %d\n", irq);
> >+			goto disable_clk;
> >+		}
> >+	}
> >+
> >  	wdev->restart_handler.notifier_call = imx2_restart_handler;
> >  	wdev->restart_handler.priority = 128;
> >  	ret = register_restart_handler(&wdev->restart_handler);
> >
> 
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