Patches to include/linux/watchdog.h to document the functions

Corey Minyard (minyard@acm.org)
Fri, 25 Jan 2002 15:26:41 -0600


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The include/linux/watchdog.h is, well, a little hard to read and
understand. I have attached a patch that documents this as best as I
can understand it. It also add a few small things. It would be nice to
get all the watchdogs to conform to one interface for things like
setting the timeout, they all seem to have their own unique ways of
doing a lot of things.

-Corey

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--- ./drivers/char/pcwd.c.watchdog Fri Jan 25 11:17:52 2002
+++ ./drivers/char/pcwd.c Fri Jan 25 11:20:52 2002
@@ -250,6 +250,8 @@
return -ENOTTY;

case WDIOC_GETSUPPORT:
+ if (supports_temp)
+ ident.options |= WDIOF_GETTEMP;
i = copy_to_user((void*)arg, &ident, sizeof(ident));
return i ? -EFAULT : 0;

--- ./include/linux/watchdog.h.watchdog Fri Jan 25 09:36:24 2002
+++ ./include/linux/watchdog.h Fri Jan 25 11:17:21 2002
@@ -14,22 +14,53 @@
#define WATCHDOG_IOCTL_BASE 'W'

struct watchdog_info {
- __u32 options; /* Options the card/driver supports */
+ __u32 options; /* Options the card/driver supports, see
+ WDIOF_xxx below. */
__u32 firmware_version; /* Firmware version of the card */
__u8 identity[32]; /* Identity of the board */
};

-#define WDIOC_GETSUPPORT _IOR(WATCHDOG_IOCTL_BASE, 0, struct watchdog_info)
-#define WDIOC_GETSTATUS _IOR(WATCHDOG_IOCTL_BASE, 1, int)
-#define WDIOC_GETBOOTSTATUS _IOR(WATCHDOG_IOCTL_BASE, 2, int)
-#define WDIOC_GETTEMP _IOR(WATCHDOG_IOCTL_BASE, 3, int)
-#define WDIOC_SETOPTIONS _IOR(WATCHDOG_IOCTL_BASE, 4, int)
-#define WDIOC_KEEPALIVE _IOR(WATCHDOG_IOCTL_BASE, 5, int)
-#define WDIOC_SETTIMEOUT _IOW(WATCHDOG_IOCTL_BASE, 6, int)
+/* Get information about what the watchdog timer supports. */
+#define WDIOC_GETSUPPORT _IOR(WATCHDOG_IOCTL_BASE, 0, struct watchdog_info)
+
+/* Return the current status of the watchdog. */
+#define WDIOC_GETSTATUS _IOR(WATCHDOG_IOCTL_BASE, 1, int)
+
+/* Return the status of the watchdog when the driver was started.
+ This will have set WFIOF_CARDRESET if the last reset was due to a
+ watchdog, and if the watchdog had an alternate reason (besides
+ timeout) for the reset, then one of the reason bits from the
+ WDIOF_xxx will be set. */
+#define WDIOC_GETBOOTSTATUS _IOR(WATCHDOG_IOCTL_BASE, 2, int)
+
+/* Return the current temperature (only for cards that have a
+ temperature probe). */
+#define WDIOC_GETTEMP _IOR(WATCHDOG_IOCTL_BASE, 3, int)
+
+/* Set options (see WDIOS_xxx for options). */
+#define WDIOC_SETOPTIONS _IOR(WATCHDOG_IOCTL_BASE, 4, int)
+
+/* Ping the keepalive to keep us alive for another timeout. */
+#define WDIOC_KEEPALIVE _IOR(WATCHDOG_IOCTL_BASE, 5, int)
+
+/* Set the timeout for the watchdog. The parameter is generally an
+ integer number of milliseconds, the watchdog timer will be set to
+ the first value larger than the given time. It will return EINVAL
+ if the timeout is beyond the capability of the watchdog timer. For
+ some boards, it is a custom timeout that is board dependent. Note
+ that this function will automatically does the keepalive for the
+ watchdog. */
+#define WDIOC_SETTIMEOUT _IOW(WATCHDOG_IOCTL_BASE, 6, int)

#define WDIOF_UNKNOWN -1 /* Unknown flag error */
#define WDIOS_UNKNOWN -1 /* Unknown status error */

+/* Various options a card may support returned by GETSUPPORT, and also
+ status returned by GETSTATUS. If the bit is set in the options
+ field returned by GETSUPPORT, then the value may be returned by
+ GETSTATUS. The SETTIMEOUT and GETTEMP are the only real
+ exceptions, they is returned by GETSUPPORT, indicating the card is
+ capable, but set by separate SETTIMEOUT and GETTEMP ioctls. */
#define WDIOF_OVERHEAT 0x0001 /* Reset due to CPU overheat */
#define WDIOF_FANFAULT 0x0002 /* Fan failed */
#define WDIOF_EXTERN1 0x0004 /* External relay 1 */
@@ -37,9 +68,22 @@
#define WDIOF_POWERUNDER 0x0010 /* Power bad/power fault */
#define WDIOF_CARDRESET 0x0020 /* Card previously reset the CPU */
#define WDIOF_POWEROVER 0x0040 /* Power over voltage */
+#define WDIOF_SETTIMEOUT 0x0080 /* Can the timeout be set? */
+#define WDIOF_GETTEMP 0x0100 /* Can the temperature be read? */
#define WDIOF_KEEPALIVEPING 0x8000 /* Keep alive ping reply */

-#define WDIOS_DISABLECARD 0x0001 /* Turn off the watchdog timer */
+/* The following are options that may be set by WDIOC_SETOPTIONS. */
+#define WDIOS_DISABLECARD 0x0001 /* Turn off the watchdog
+ timer. If the watchdog is
+ set to go off even if the
+ device gets closed, the
+ application can disable the
+ watchdog to prevent it from
+ resetting the card if the
+ reboot is not wanted. Note
+ that setting the timeout or
+ re-opening the driver will
+ re-enable the watchdog. */
#define WDIOS_ENABLECARD 0x0002 /* Turn on the watchdog timer */
#define WDIOS_TEMPPANIC 0x0004 /* Kernel panic on temperature trip */

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