linux-kernel - Re: [PATCH 3/3] watchdog/aspeed: add support for dual boot

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Message-ID: <550d98a41f8c36effb8147201d6c5fdc762994ea.camel@yadro.com>
Date:   Thu, 22 Aug 2019 17:24:27 +0300
From:   Ivan Mikhaylov <i.mikhaylov@...ro.com>
To:     Guenter Roeck <linux@...ck-us.net>
CC:     Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Joel Stanley <joel@....id.au>,
        Andrew Jeffery <andrew@...id.au>,
        <linux-watchdog@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-aspeed@...ts.ozlabs.org>, <linux-kernel@...r.kernel.org>,
        "Alexander Amelkin" <a.amelkin@...ro.com>
Subject: Re: [PATCH 3/3] watchdog/aspeed: add support for dual boot

On Thu, 2019-08-22 at 06:55 -0700, Guenter Roeck wrote:
> On Thu, Aug 22, 2019 at 12:15:20PM +0300, Ivan Mikhaylov wrote:
> > On Wed, 2019-08-21 at 09:32 -0700, Guenter Roeck wrote:
> > > > +	writel(WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION,
> > > > +			wdt->base + WDT_CLEAR_TIMEOUT_STATUS);
> > > > +	wdt->wdd.bootstatus |= WDIOF_EXTERN1;
> > > 
> > > The variable reflects the _boot status_. It should not change after
> > > booting.
> > 
> > Okay, then perhaps may we set 'status' handler for watchdog device and
> > check 
> > 'status' file? Right now 'bootstatus' and 'status' are same because there is
> > no
> > handler for 'status'.
> > 
> 
> You would still have to redefine one of the status bits to mean something
> driver specific. You would also still have two different flags to read
> and control cs0 - to read the status, you would read an ioctl (or the
> status sysfs attribute), to write it you would write into access_cs0.
> 
> I guess I must be missing something. What is the problem with using
> access_cs0 for both ?
> 
> Guenter
> 

There is no problem, I'll do that way, thanks!