[PATCH 9/10 v2] Generic Watchdog Timer Driver

From: Wim Van Sebroeck
Date: Sat Jun 18 2011 - 13:27:33 EST

watchdog: WatchDog Timer Driver Core - Part 9

Add support for extra ioctl calls by adding a
ioctl watchdog operation. This operation will be
called before we do our own handling of ioctl
commands. This way we can override the internal
ioctl command handling and we can also add
extra ioctl commands. The ioctl watchdog operation
should return the appropriate error codes or
-ENOIOCTLCMD if the ioctl command should be handled
through the internal ioctl handling of the framework.

Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Wim Van Sebroeck <wim@xxxxxxxxx>

diff -urN linux-2.6.38-generic-part8/Documentation/watchdog/watchdog-kernel-api.txt linux-2.6.38-generic-part9/Documentation/watchdog/watchdog-kernel-api.txt
--- linux-2.6.38-generic-part8/Documentation/watchdog/watchdog-kernel-api.txt 2011-06-17 10:03:41.326632851 +0200
+++ linux-2.6.38-generic-part9/Documentation/watchdog/watchdog-kernel-api.txt 2011-06-17 10:14:55.514632632 +0200
@@ -74,6 +74,7 @@
int (*ping)(struct watchdog_device *);
int (*status)(struct watchdog_device *);
int (*set_timeout)(struct watchdog_device *, int);
+ long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);

It is important that you first define the module owner of the watchdog timer
@@ -119,6 +120,10 @@
was just used to re-program the watchdog timer device.
(Note: the WDIOF_SETTIMEOUT needs to be set in the options field of the
watchdog's info structure).
+* ioctl: if this routine is present then it will be called first before we do
+ our own internal ioctl call handling. This routine should return -ENOIOCTLCMD
+ if a command is not supported. The parameters that are passsed to the ioctl
+ call are: watchdog_device, cmd and arg.

The status bits should (preferably) be set with the set_bit and clear_bit alike
bit-operations. The status bit's that are defined are:
diff -urN linux-2.6.38-generic-part8/drivers/watchdog/core/watchdog_dev.c linux-2.6.38-generic-part9/drivers/watchdog/core/watchdog_dev.c
--- linux-2.6.38-generic-part8/drivers/watchdog/core/watchdog_dev.c 2011-06-17 10:03:41.326632851 +0200
+++ linux-2.6.38-generic-part9/drivers/watchdog/core/watchdog_dev.c 2011-06-17 10:14:55.522632632 +0200
@@ -209,6 +209,12 @@

trace("%p, %u, %li", file, cmd, arg);

+ if (wdd->ops->ioctl) {
+ err = wdd->ops->ioctl(wdd, cmd, arg);
+ if (err != -ENOIOCTLCMD)
+ return err;
+ }
switch (cmd) {
return copy_to_user(argp, wdd->info,
diff -urN linux-2.6.38-generic-part8/include/linux/watchdog.h linux-2.6.38-generic-part9/include/linux/watchdog.h
--- linux-2.6.38-generic-part8/include/linux/watchdog.h 2011-06-17 12:17:52.893063162 +0200
+++ linux-2.6.38-generic-part9/include/linux/watchdog.h 2011-06-17 12:18:05.261063514 +0200
@@ -72,6 +72,7 @@
int (*ping)(struct watchdog_device *);
int (*status)(struct watchdog_device *);
int (*set_timeout)(struct watchdog_device *, int);
+ long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);

/* The structure that defines a watchdog device */
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