Re: [PATCH 1/2] watchdog: ImgTec PDC Watchdog Timer Driver

Ezequiel Garcia
2014-11-13T13:06:50Z

On 11/12/2014 12:18 PM, Naidu.Tellapati@imgtec.com wrote:
[..]
> +
> +static int pdc_wdt_keepalive(struct watchdog_device *wdt_dev)
> +{
> + struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + writel(PDC_WD_TICKLE1_MAGIC, wdt->base + PDC_WD_TICKLE1);
> + writel(PDC_WD_TICKLE2_MAGIC, wdt->base + PDC_WD_TICKLE2);
> +
> + return 0;
> +}
> +
> +static int pdc_wdt_stop(struct watchdog_device *wdt_dev)
> +{
> + unsigned int val;
> + struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + val = readl(wdt->base + PDC_WD_CONFIG);
> + val &= ~BIT(31);
> + writel(val, wdt->base + PDC_WD_CONFIG);
> + /* Must tickle to finish the stop */
> + pdc_wdt_keepalive(wdt_dev);
> +
> + return 0;
> +}
> +
> +static int pdc_wdt_set_timeout(struct watchdog_device *wdt_dev,
> + unsigned int new_timeout)
> +{
> + unsigned int val;
> + struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + if (new_timeout < PDC_WD_MIN_TIMEOUT ||
> + new_timeout > PDC_WD_MAX_TIMEOUT)
> + return -EINVAL;
> +
> + wdt->wdt_dev.timeout = new_timeout;
> +
> + /* round up to the next power of 2 */
> + new_timeout = order_base_2(new_timeout);
> + val = readl(wdt->base + PDC_WD_CONFIG);
> +
> + /* number of 32.768KHz clocks, 2^(n+1) (14 is 1 sec) */
> + val &= ~PDC_WD_CONFIG_DELAY;
> + val |= (new_timeout + MIN_TIMEOUT_SHIFT) << PDC_WD_CONFIG_DELAY_SHIFT;
> + writel(val, wdt->base + PDC_WD_CONFIG);
> +
> + return 0;
> +}
> +
> +static int pdc_wdt_set_pretimeout(struct watchdog_device *wdt_dev,
> + unsigned int new_pretimeout)
> +{
> + int delay;
> + unsigned int val;
> + struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + /*
> + * Pretimeout is measured in seconds before main timeout.
> + * Subtract and round it once, and it will effectively change
> + * if the main timeout is changed.
> + */
> + delay = wdt->wdt_dev.timeout;
> + if (!new_pretimeout)
> + new_pretimeout = PDC_WD_MAX_TIMEOUT;
> + else if (new_pretimeout > 0 && new_pretimeout < delay)
> + new_pretimeout = delay - new_pretimeout;
> + else
> + return -EINVAL;
> +
> + pretimeout = new_pretimeout;
> + new_pretimeout = ilog2(new_pretimeout);
> + val = readl(wdt->base + PDC_WD_CONFIG);
> +
> + /* number of 32.768KHz clocks, 2^(n+1) (14 is 1 sec) */
> + val &= ~PDC_WD_CONFIG_REMIND;
> + val |= (new_pretimeout + MIN_TIMEOUT_SHIFT)
> + << PDC_WD_CONFIG_REMIND_SHIFT;
> + writel(val, wdt->base + PDC_WD_CONFIG);
> + wdt->pretimeout = pretimeout;
> +
> + return 0;
> +}
> +
> +/* Start the watchdog timer (delay should already be set */
> +static int pdc_wdt_start(struct watchdog_device *wdt_dev)
> +{
> + int ret;
> + unsigned int val;
> + struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + ret = pdc_wdt_set_timeout(&wdt->wdt_dev, wdt->wdt_dev.timeout);
> + if (ret < 0)
> + return ret;
> +

Please double check it, but I think you don't need to set the timeout
here. You set the default at probe time; and then it'll get set by the
ioctl if it changes.

--
Ezequiel