URL
https://opencores.org/ocsvn/or1k/or1k/trunk
Go to most recent revision |
Details |
Compare with Previous |
View Log
| Line No. |
Rev |
Author |
Line |
| 1 |
1625 |
jcastillo |
Watchdog Timer Interfaces For The Linux Operating System
|
| 2 |
|
|
|
| 3 |
|
|
Alan Cox
|
| 4 |
|
|
|
| 5 |
|
|
Custom Linux Driver And Program Development
|
| 6 |
|
|
|
| 7 |
|
|
|
| 8 |
|
|
The following watchdog drivers are currently implemented:
|
| 9 |
|
|
|
| 10 |
|
|
ICS WDT501-P
|
| 11 |
|
|
ICS WDT501-P (no fan tachometer)
|
| 12 |
|
|
ICS WDT500-P
|
| 13 |
|
|
Software Only
|
| 14 |
|
|
|
| 15 |
|
|
All four interfaces provide /dev/watchdog, which when open must be written
|
| 16 |
|
|
to within a minute or the machine will reboot. Each write delays the reboot
|
| 17 |
|
|
time another minute. In the case of the software watchdog the ability to
|
| 18 |
|
|
reboot will depend on the state of the machines and interrupts. The hardware
|
| 19 |
|
|
boards physically pull the machine down off their own onboard timers and
|
| 20 |
|
|
will reboot from almost anything.
|
| 21 |
|
|
|
| 22 |
|
|
A second temperature monitoring interface is available on the WDT501P cards
|
| 23 |
|
|
and provides /dev/temperature. This is the machine internal temperature in
|
| 24 |
|
|
degrees farenheit. Each read returns a single byte giving the temperature.
|
| 25 |
|
|
|
| 26 |
|
|
The third interface logs kernel messages on additional alert events.
|
| 27 |
|
|
|
| 28 |
|
|
Both software and hardware watchdog drivers are available in the standard
|
| 29 |
|
|
kernel. If you are using the software watchdog, you probably also want
|
| 30 |
|
|
to use "panic=60" as a boot argument as well.
|
| 31 |
|
|
|
| 32 |
|
|
Features
|
| 33 |
|
|
--------
|
| 34 |
|
|
WDT501P WDT500P Software
|
| 35 |
|
|
Reboot Timer X X X
|
| 36 |
|
|
External Reboot X X o
|
| 37 |
|
|
Temperature X o o
|
| 38 |
|
|
Fan Speed X o o
|
| 39 |
|
|
Power Under X o o
|
| 40 |
|
|
Power Over X o o
|
| 41 |
|
|
Overheat X o o
|
| 42 |
|
|
|
| 43 |
|
|
The external event interfaces on the WDT boards are not currently supported.
|
| 44 |
|
|
Minor numbers are however allocated for it.
|
| 45 |
|
|
|
| 46 |
|
|
|
| 47 |
|
|
Example Watchdog Driver
|
| 48 |
|
|
-----------------------
|
| 49 |
|
|
|
| 50 |
|
|
#include
|
| 51 |
|
|
#include
|
| 52 |
|
|
#include
|
| 53 |
|
|
|
| 54 |
|
|
int main(int argc, const char *argv[])
|
| 55 |
|
|
{
|
| 56 |
|
|
int fd=open("/dev/watchdog",O_WRONLY);
|
| 57 |
|
|
if(fd==-1)
|
| 58 |
|
|
{
|
| 59 |
|
|
perror("watchdog");
|
| 60 |
|
|
exit(1);
|
| 61 |
|
|
}
|
| 62 |
|
|
while(1)
|
| 63 |
|
|
{
|
| 64 |
|
|
write(fd,"\0",1);
|
| 65 |
|
|
sleep(10);
|
| 66 |
|
|
}
|
| 67 |
|
|
}
|
| 68 |
|
|
|
| 69 |
|
|
|
| 70 |
|
|
Contact Information
|
| 71 |
|
|
|
| 72 |
|
|
People keep asking about the WDT watchdog timer hardware: The phone contacts
|
| 73 |
|
|
for Industrial Computer Source are:
|
| 74 |
|
|
|
| 75 |
|
|
US: 619 677 0877 (sales) 0895 (fax)
|
| 76 |
|
|
UK: 01243 533900
|
| 77 |
|
|
France (1) 69.18.74.30
|
| 78 |
|
|
|
| 79 |
|
|
Industrial Computer Source
|
| 80 |
|
|
9950 Barnes Canyon Road
|
| 81 |
|
|
San Diego, CA
|
| 82 |
|
|
|
| 83 |
|
|
and please mention Linux when enquiring.
|
© copyright 1999-2024
OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.