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Message-ID: <563835C0.5010204@roeck-us.net>
Date: Mon, 2 Nov 2015 20:19:12 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Robin Gong <b38343@...escale.com>, wim@...ana.be
Cc: linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v1 2/2] watchdog: imx2_wdt: add set_pretimeout interface
On 11/02/2015 07:29 PM, Robin Gong wrote:
> Enable set_pretimeout interface and trigger the pretimeout interrupt before
> watchdog timeout event happen.
>
> Signed-off-by: Robin Gong <b38343@...escale.com>
> ---
> drivers/watchdog/imx2_wdt.c | 67 ++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 66 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
> index 0bb1a1d..d3c6b07 100644
> --- a/drivers/watchdog/imx2_wdt.c
> +++ b/drivers/watchdog/imx2_wdt.c
> @@ -24,7 +24,9 @@
> #include <linux/clk.h>
> #include <linux/delay.h>
> #include <linux/init.h>
> +#include <linux/interrupt.h>
> #include <linux/io.h>
> +#include <linux/irq.h>
Are those two new includes both needed ?
> #include <linux/jiffies.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> @@ -52,12 +54,18 @@
> #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 << 0) /* Watchdog Interrupt Timeout */
> +
"<< 0" doesn't really add any value here.
> #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*/
>
((s) * 2)
Ah yes, WDOG_SEC_TO_COUNT should also use (s).
> struct imx2_wdt_device {
> struct clk *clk;
> @@ -80,7 +88,8 @@ 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 +216,59 @@ static inline void imx2_wdt_ping_if_active(struct watchdog_device *wdog)
> }
> }
>
> +static int imx2_wdt_check_pretimeout_set(struct imx2_wdt_device *wdev)
> +{
> + u32 val;
> +
> + regmap_read(wdev->regmap, IMX2_WDT_WICR, &val);
> + return (val & IMX2_WDT_WICR_WIE) ? 1 : 0;
I don't understand the point of this function.
You check if IMX2_WDT_WICR_WIE is set,
> +}
> +
> +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);
> +
What is the time here ? Is pretimeout the number of seconds
until the interrupt occurs, or the number of seconds before the actual
timeout (as per API) ?
> + if (!imx2_wdt_check_pretimeout_set(wdev))
> + val |= IMX2_WDT_WICR_WIE; /*enable*/
if IMX2_WDT_WICR_WIE is not set, you set it,
> +
> + regmap_write(wdev->regmap, IMX2_WDT_WICR, val);
> +
and write the result unconditionally. Unless I am missing something,
regmap_write, wdev->regmap, IMX2_WDT_WICR, val | IMX2_WDT_WICR_WIE);
would accomplish exactly the same.
> + 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);
> + dev_warn(&pdev->dev, "pre-timeout:%d, %d Seconds remained\n",
> + wdog->pretimeout, wdog->timeout - wdog->pretimeout);
The idea here is that this should trigger a panic.
> + }
> + 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 +285,7 @@ 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);
> @@ -253,6 +310,14 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
> return PTR_ERR(wdev->clk);
> }
>
> + irq = platform_get_irq(pdev, 0);
This makes the irq mandatory. What if a platform doesn't have one configured ?
> + 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);
You got it, but you could not request it.
This is also a bit early, as the interrupt handler uses variables which are not yet
initialized.
> + return ret;
> + }
> +
> wdog = &wdev->wdog;
> wdog->info = &imx2_wdt_info;
> wdog->ops = &imx2_wdt_ops;
>
--
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