ADLINK CSA-5200 - Manual (Page 36)

36
CSA-5200
PROTOTYPE
static ssize_t write(struct file *file, const char __user *data,size_t len, loff_t *ppos)
DESCRIPTION
This function is used to write information to be given to watchdog device.
int write(int handle, void *buf, int nbyte) may be used in client to call this feature.
PARAMETERS
handle
[IN] File handle to the watchdog;
buf
[IN] Buffer to write;
nbyte
[IN] Count of bytes;
RETURN
Number of bytes actually written: success
-1: error
6.2.3 ioctl
The Watchdog Driver provides several ioctl options:
WDIOS_DISABLECARD
, used to turn off the watchdog timer. The Watchdog Driver support
module parameter WATCHDOG_NOWAYOUT. If it is set, there is no way of disabling the
watchdog once it has been started. So, if the watchdog daemon crashes, the system will
reboot after the timeout has passed.
WDIOS_ENABLECARD , used to turn on the watchdog timer.
WDIOC_SETOPTIONS
, used to set the watchdog status.
WDIOC_GETSTATUS
, used to determines the status supported by watchdog ioctl. The
status bit of the device does not allow distinguishing between a regular system reset and a
watchdog forced reset. But, in test mode it is useful, so it is supported through
WDIOC_GETSTATUS watchdog ioctl. Additionally the driver reports the keepalive signal and
the acception of the magic.
WDIOC_SETTIMEOUT
, used to change the watchdog timeout parameter (1s-255s). The
Watchdog Driver support module parameter DEFAULT_TIMEOUT. If it set then the
Watchdog Driver will use it as the watchdog timeout parameter. If it is not set, the default
watchdog timeout parameter is 5s.
WDIOC_GETTIMEOUT , used to query the watchdog timeout parameter.
WDIOC_KEEPALIVE
, used to feed the watchdog, just like the write () interface.
WDIOC_ENABLEBYPS
, which is a custom command, used to enable the LAN bypass.
Defined as below:
#define WDIOC_ENABLEBYPS _IOR(WATCHDOG_IOCTL_BASE, 101, int)
WDIOC_DISABLEBYPS , which is a custom command, used to disable the LAN bypass.
Defined as below:
#define WDIOC_DISABLEBYPS _IOR(WATCHDOG_IOCTL_BASE, 102, int)
PROTOTYPE
static long ioctl(struct file *file, unsigned int cmd, unsigned long arg)