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

[Ezequiel Garcia <ezequiel.garcia-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org>]

On 11/12/2014 12:18 PM, Naidu.Tellapati-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org 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
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