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

Guenter Roeck
2015-11-03T07:48:31Z

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).

> +
> + 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);
>