[RFC PATCH 1/5] watchdog: Add API to trigger reboots

On 05/02/2014 03:01 AM, Will Deacon wrote:

Hi Guenter,

This looks pretty sensible to me (and the arm/arm64 bits look fine too), but
I have one question below...

On Thu, May 01, 2014 at 04:41:29PM +0100, Guenter Roeck wrote:

quoted

Some hardware implements reboot through its watchdog hardware,
for example by triggering a watchdog timeout. Platform specific
code starts to spread into watchdog drivers, typically by setting
pointers to a callback functions which is then called from the
platform reset handler.

To simplify code and provide a unified API to trigger reboots by
watchdog drivers, provide a single API to trigger such reboots
through the watchdog subsystem.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
  drivers/watchdog/watchdog_core.c |   17 +++++++++++++++++
  include/linux/watchdog.h         |   11 +++++++++++
  2 files changed, 28 insertions(+)

diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index cec9b55..4ec6e2f 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c

@@ -43,6 +43,17 @@
  static DEFINE_IDA(watchdog_ida);
  static struct class *watchdog_class;

+static struct watchdog_device *wdd_reboot_dev;
+
+void watchdog_do_reboot(enum reboot_mode mode, const char *cmd)
+{
+	if (wdd_reboot_dev) {
+		if (wdd_reboot_dev->ops->reboot)
+			wdd_reboot_dev->ops->reboot(wdd_reboot_dev, mode, cmd);
+	}
+}

What reboot_mode values would you expect a watchdog to support other than
REBOOT_HARD? Also, is the cmd even useful here?

Answer is "I don't know" in both cases. I thought about dropping the parameters,
but then I thought it does not hurt to have them around either. I am open to
suggestions and to dropping the parameters if everyone agrees that they are
useless.

Guenter