linux-kernel - Re: [PATCH 1/5] wdt: sunxi: Move restart code to the watchdog driver

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Message-ID: <20140428230702.GN3134@lukather>
Date:	Mon, 28 Apr 2014 16:07:02 -0700
From:	Maxime Ripard <maxime.ripard@...e-electrons.com>
To:	Guenter Roeck <linux@...ck-us.net>
Cc:	Arnd Bergmann <arnd@...db.de>, wim@...ana.be, dbaryshkov@...il.com,
	dwmw2@...radead.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-watchdog@...r.kernel.org,
	linux-sunxi@...glegroups.com
Subject: Re: [PATCH 1/5] wdt: sunxi: Move restart code to the watchdog driver

Hi,

On Sat, Apr 26, 2014 at 08:31:07AM -0700, Guenter Roeck wrote:
> On 04/23/2014 08:04 AM, Maxime Ripard wrote:
> >Most of the watchdog code is duplicated between the machine restart code and
> >the watchdog driver. Add the restart hook to the watchdog driver, to be able to
> >remove it from the machine code eventually.
> >
> >Signed-off-by: Maxime Ripard <maxime.ripard@...e-electrons.com>
> >---
> >  drivers/watchdog/sunxi_wdt.c | 33 +++++++++++++++++++++++++++++++++
> >  1 file changed, 33 insertions(+)
> >
> >diff --git a/drivers/watchdog/sunxi_wdt.c b/drivers/watchdog/sunxi_wdt.c
> >index cd00a7836cdc..0644c45d2b60 100644
> >--- a/drivers/watchdog/sunxi_wdt.c
> >+++ b/drivers/watchdog/sunxi_wdt.c
> >@@ -14,6 +14,7 @@
> >   */
> >
> >  #include <linux/clk.h>
> >+#include <linux/delay.h>
> >  #include <linux/err.h>
> >  #include <linux/init.h>
> >  #include <linux/io.h>
> >@@ -22,9 +23,12 @@
> >  #include <linux/moduleparam.h>
> >  #include <linux/of.h>
> >  #include <linux/platform_device.h>
> >+#include <linux/reboot.h>
> >  #include <linux/types.h>
> >  #include <linux/watchdog.h>
> >
> >+#include <asm/system_misc.h>
> >+
> >  #define WDT_MAX_TIMEOUT         16
> >  #define WDT_MIN_TIMEOUT         1
> >  #define WDT_MODE_TIMEOUT(n)     ((n) << 3)
> >@@ -70,6 +74,30 @@ static const int wdt_timeout_map[] = {
> >  	[16] = 0b1011, /* 16s */
> >  };
> >
> >+static struct sunxi_wdt_dev *sunxi_restart_ctx;
> >+
> >+static void sun4i_wdt_restart(enum reboot_mode mode, const char *cmd)
> >+{
> >+	if (!sunxi_restart_ctx)
> >+		return;
> >+
> The only condition where this can happen if is there is a race between the calling
> code and the remove function below. If that race really exists, it could as well
> happen after this check, so the check does not really provide any value and can
> be removed.
> 
> Note that I find the variable name a bit misleading. It isn't a context,
> it is the poitner to sunxi_wdt_dev. What is really needed is wdt_base,
> not this pointer. Would it make more sense to provide that pointer
> directly instead, like you did in the code for the A31 ?

Hmm, right, I'll change this.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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