Re: [PATCH v2 2/2] watchdog: imx2_wdt: add set_pretimeout interface

Robin Gong
2015-11-03T08:06:44Z

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);
> >
>