Subject: [PATCHv2 5/5] ARM: picoxcell: implement watchdog restart

From: [email-masked] (Jamie Iles)
Date: Sun, 18 Dec 2011 09:41:13 +0000

On Sun, Dec 18, 2011 at 08:13:27AM +0000, Russell King - ARM Linux wrote:
> On Sat, Dec 17, 2011 at 09:17:00PM +0100, Arnd Bergmann wrote:
> > > +static void picoxcell_wdt_restart(char mode, const char *cmd)
> > > +{
> > > +	/*
> > > +	 * Configure the watchdog to reset with the shortest possible timeout
> > > +	 * and give it chance to do the reset.
> > > +	 */
> > > +	if (wdt_regs) {
> > > +		__raw_writel(WDT_CTRL_REG_EN_MASK, wdt_regs + WDT_CTRL_REG_OFFS);
> > > +		__raw_writel(0, wdt_regs + WDT_TIMEOUT_REG_OFFS);
> > > +		mdelay(500);
> > > +	}
> > > +}
> > 
> > Does this work if the real watchdog is still running, on a preemtible kernel?
> > 
> > Also, please always use writel_relaxed instead of __raw_writel, and try to use
> > msleep instead of mdelay by default. If msleep doesn't work here because it
> > actually causes the system not to be reset, just add a comment.
> 
> Restarting can be called from atomic contexts, so any function which may
> sleep must not be used.  That include sioremap.

Thanks for clarifying Russell.  I'll add a comment or two to that effect 
and change the __raw_writel's to writel_relaxed().

Thanks,

Jamie