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diff --git a/Documentation/man4/wdt_mpc5xxx.4 b/Documentation/man4/wdt_mpc5xxx.4 deleted file mode 100755 index ca41e2895e..0000000000 --- a/Documentation/man4/wdt_mpc5xxx.4 +++ /dev/null @@ -1,214 +0,0 @@ -.\" Hey Emacs! This file is -*- nroff -*- source. -.\" -.\" Copyright 2002 Detlev Zundel (dzu@denx.de) -.\" -.\" Permission is granted to make and distribute verbatim copies of this -.\" manual provided the copyright notice and this permission notice are -.\" preserved on all copies. -.\" -.\" Permission is granted to copy and distribute modified versions of this -.\" manual under the conditions for verbatim copying, provided that the -.\" entire resulting derived work is distributed under the terms of a -.\" permission notice identical to this one -.\" -.TH WDT_MPC5XXX "Denx specific extensions" -.SH NAME -wdt_mpc5xxx \- Watchdog driver -.SH SYNOPSIS -.B #include <linux/asm/wdt_mpc5xxx.h> -.SH DESCRIPTION -The -.B wdt_mpc5xxx -driver implements a character device with major number 10 and minor -number 130. It is a software abstraction of the hardware watchdog -with two different APIs. While the driver periodically triggers the -hardware watchdog, the software can setup independent timeout periods. - -.SH "REGULAR API" -The regular API provides a facility to setup a watchdog behaviour -.I shared -by all processes using the driver. This interface uses read(2), -write(2) and the first two ioctl(2) calls listed below. The -parameterless ioctl(2) calls select the operational mode of the -driver, which can be -.I open-only -or -.I always. - -In open-only mode, the watchdog will not expire if the device file is -not opened by any process, while in always -mode the behaviour is independent of the device file being opened. - -Reading from the device file will return an unsigned integer denoting -the number of seconds left till the watchdog expires. Writing an -unsigned integer to the device file will set the expiration period in -seconds. Note that the hardware watchdog will be triggered -independently with a configurable period. See the section -CONFIGURATION for details. - -An expiration of the watchdog will trigger a hard-reset of the machine. - -.SH "CHAIN API" -The second API, which is implemented only through calls to ioctl(2), -can be used to register configurable -.I watchdog chains -from either user or kernel space. A watchdog chain -is identified by an unsigned integer and can contain up to three -.I action stages. -A -.I time interval -in seconds and an -.I action -is associated with each stage. When the chain is not reset before the -interval elapses, the associated action is triggered and the chain -moves on to the next stage. - -A chain can request to kill the registering process if the interval -elapses. In this case a restarted process can register with the -driver giving the same identifier and reset the chain. This is the -main reason why there is no association between chains and processes -or open device files. - -For a detailed description of the possible chain configurations, see -the description of the -.B WDT_REGISTER -ioctl call. - -Note that when mixing the two interfaces, the second API takes -precedence. That is, expiry of the interval set by writing to the -device file while a chain is registered, will not trigger any actions. - -Also note that the default operational mode of the driver, -i.e. open-only or always can only be configured in the source-code. - -.SH IOCTLS -.TP -WDT_OPEN_ONLY -This parameterless call selects the -.I open-only -operational mode of the driver as described above. - -.TP -WDT_ALWAYS -Also a parameterless call, this sets the driver to the -.I always -operational mode. - -.TP -WDT_REGISTER -This and the two following ioctls constitute the -.I chain interface -described above. The parameter given to the call is a pointer to a -structure with the following layout: - - typedef struct wdt_param { - unsigned chainid; - unsigned long timer_count[3]; - int action[3]; - int signal; - } wdt_param_t; - -Each stage is configured with entries in the arrays -.I timer_count -and -.I action. -The timer_count contains the length of the interval in seconds -while action contains one of the constants -.B WDT_ACTION_SIGNAL, WDT_ACTION_KILL, -.B WDT_ACTION_REBOOT -and -.B WDT_ACTION_RESET. -A timer_count of zero signals the end of the chain. - -The ACTION_SIGNAL will send the configurable signal with number -.I signal -to the registering process, while ACTION_KILL signals SIGKILL which -can not be caught by the registered process. -ACTION_REBOOT tries a soft reboot and ACTION_RESET -triggers a hard-reset of the machine. - -When stages of the chain are to be left unused, they should be filled -with zero entries. - -Note that internally a hard-reset stage is appended as a stop entry -ensuring a chain will never exceed its stages. - -.TP -WDT_RESET -This call resets the chain denoted by the unsigned integer passed to -it. When reset, a chain will expire beginning with stage zero again. - -.TP -WDT_UNREGISTER -As closing the device file will not have any effect on chains, a -process must unregister a chain if the service is no longer needed. -This can be done with this ioctl taking an unsigned integer as a -parameter denoting the chain to be unregistered. - -.SH "IOCTL RESULT VALUES" -On successful completion, the above calls to ioctl(2) return 0. When -invalid parameters are provided or an error occurs, a negative value -will be returned and -.B errno -set accordingly. Specifically -.B "EINVAL, EFAULT, ENOMEM" -can be returned. - -.SH "KERNEL INTERFACE" -Modules can also register with the chain API of the watchdog driver. -For this the three functions -.B wdt_register_mon_chain, wdt_reset_mon_chain -and -.B wdt_unregister_mon_chain -are exported from the driver. The first function takes one argument, -namely a pointer to a -.I wdt_param -structure. The other two calls take a pointer to an unsigned integer -as a parameter, namely the chain id of the chain to be reset or -unregistered. - -.SH CONFIGURATION -The driver is configurable through parameters passed to the driver -through the Linux commandline as -.B "wdt=<opts>". -Multiple options can be seperated by -commas, as usual. - -.B timeout:<n> -will set the expiry period of the regular driver API to <n> seconds. - -.B period:<n> -sets the period with which the hardware watchdog is triggered to <n> -jiffies. This usually means 1/100th of a second. The default for the -MPC5xxx is (1*HZ), resulting in 1 watchdog trigger per second. - -.B off -will disable the software APIs of the driver but still trigger the -hardware watchdog as described previously. - -.SH EXAMPLE -The following code snippet registers a watchdog chain whose first -stage will expire after 3 seconds and send the SIGUSR1 signal to the -process. When 5 seconds after this the chain is not reset, the -machine will do a hard-reset. - - wdt_param_t param; - - /* Setup signal handling */ - signal(SIGUSR1, got_signal); - - param.chainid=823; - param.timer_count[0]=3; - param.action[0]=WDT_ACTION_KILL; - param.signal=SIGUSR1; - param.timer_count[1]=5; - param.action[1]=WDT_ACTION_RESET; - - /* Register chain */ - ioctl(fd, WDT_REGISTER, ¶m); - .. - /* Reset chain */ - ioctl(fd, WDT_RESET, ¶m.chainid); - -.SH FILES - /dev/watchdog |