linux-kernel - Re: [PATCH 1/2] watchdog: davinci

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Date:   Mon, 11 Dec 2017 15:15:51 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     David Lechner <david@...hnology.com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        linux-watchdog@...r.kernel.org, Sekhar Nori <nsekhar@...com>,
        Kevin Hilman <khilman@...nel.org>,
        Wim Van Sebroeck <wim@...ana.be>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] watchdog: davinci_wdt: add restart function

On Mon, Dec 11, 2017 at 11:21:08AM -0600, David Lechner wrote:
> This adds a restart function to the davinci watchdog timer driver.
> 
> This is copied from arch/arm/mach-davinci/time.c and will allow us to
> remove the code from there.
> 
> Signed-off-by: David Lechner <david@...hnology.com>

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
>  drivers/watchdog/davinci_wdt.c | 38 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 38 insertions(+)
> 
> diff --git a/drivers/watchdog/davinci_wdt.c b/drivers/watchdog/davinci_wdt.c
> index 2f46487..3e4c592 100644
> --- a/drivers/watchdog/davinci_wdt.c
> +++ b/drivers/watchdog/davinci_wdt.c
> @@ -140,6 +140,42 @@ static unsigned int davinci_wdt_get_timeleft(struct watchdog_device *wdd)
>  	return wdd->timeout - timer_counter;
>  }
>  
> +static int davinci_wdt_restart(struct watchdog_device *wdd,
> +			       unsigned long action, void *data)
> +{
> +	struct davinci_wdt_device *davinci_wdt = watchdog_get_drvdata(wdd);
> +	u32 tgcr, wdtcr;
> +
> +	/* disable, internal clock source */
> +	iowrite32(0, davinci_wdt->base + TCR);
> +
> +	/* reset timer, set mode to 64-bit watchdog, and unreset */
> +	tgcr = 0;
> +	iowrite32(tgcr, davinci_wdt->base + TGCR);
> +	tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
> +	iowrite32(tgcr, davinci_wdt->base + TGCR);
> +
> +	/* clear counter and period regs */
> +	iowrite32(0, davinci_wdt->base + TIM12);
> +	iowrite32(0, davinci_wdt->base + TIM34);
> +	iowrite32(0, davinci_wdt->base + PRD12);
> +	iowrite32(0, davinci_wdt->base + PRD34);
> +
> +	/* put watchdog in pre-active state */
> +	wdtcr = WDKEY_SEQ0 | WDEN;
> +	iowrite32(wdtcr, davinci_wdt->base + WDTCR);
> +
> +	/* put watchdog in active state */
> +	wdtcr = WDKEY_SEQ1 | WDEN;
> +	iowrite32(wdtcr, davinci_wdt->base + WDTCR);
> +
> +	/* write an invalid value to the WDKEY field to trigger a restart */
> +	wdtcr = 0x00004000;
> +	iowrite32(wdtcr, davinci_wdt->base + WDTCR);
> +
> +	return 0;
> +}
> +
>  static const struct watchdog_info davinci_wdt_info = {
>  	.options = WDIOF_KEEPALIVEPING,
>  	.identity = "DaVinci/Keystone Watchdog",
> @@ -151,6 +187,7 @@ static const struct watchdog_ops davinci_wdt_ops = {
>  	.stop		= davinci_wdt_ping,
>  	.ping		= davinci_wdt_ping,
>  	.get_timeleft	= davinci_wdt_get_timeleft,
> +	.restart	= davinci_wdt_restart,
>  };
>  
>  static int davinci_wdt_probe(struct platform_device *pdev)
> @@ -195,6 +232,7 @@ static int davinci_wdt_probe(struct platform_device *pdev)
>  
>  	watchdog_set_drvdata(wdd, davinci_wdt);
>  	watchdog_set_nowayout(wdd, 1);
> +	watchdog_set_restart_priority(wdd, 128);
>  
>  	wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	davinci_wdt->base = devm_ioremap_resource(dev, wdt_mem);
> -- 
> 2.7.4
>