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63 lines
2.1 KiB
63 lines
2.1 KiB
============================================================ |
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WDT Watchdog Timer Interfaces For The Linux Operating System |
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Last Reviewed: 10/05/2007 |
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Alan Cox <[email protected]> |
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- ICS WDT501-P |
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- ICS WDT501-P (no fan tachometer) |
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- ICS WDT500-P |
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All the interfaces provide /dev/watchdog, which when open must be written |
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to within a timeout or the machine will reboot. Each write delays the reboot |
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time another timeout. In the case of the software watchdog the ability to |
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reboot will depend on the state of the machines and interrupts. The hardware |
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boards physically pull the machine down off their own onboard timers and |
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will reboot from almost anything. |
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A second temperature monitoring interface is available on the WDT501P cards. |
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This provides /dev/temperature. This is the machine internal temperature in |
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degrees Fahrenheit. Each read returns a single byte giving the temperature. |
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The third interface logs kernel messages on additional alert events. |
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The ICS ISA-bus wdt card cannot be safely probed for. Instead you need to |
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pass IO address and IRQ boot parameters. E.g.:: |
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wdt.io=0x240 wdt.irq=11 |
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Other "wdt" driver parameters are: |
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=========== ====================================================== |
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heartbeat Watchdog heartbeat in seconds (default 60) |
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nowayout Watchdog cannot be stopped once started (kernel |
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build parameter) |
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tachometer WDT501-P Fan Tachometer support (0=disable, default=0) |
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type WDT501-P Card type (500 or 501, default=500) |
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=========== ====================================================== |
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Features |
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-------- |
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================ ======= ======= |
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WDT501P WDT500P |
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================ ======= ======= |
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Reboot Timer X X |
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External Reboot X X |
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I/O Port Monitor o o |
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Temperature X o |
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Fan Speed X o |
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Power Under X o |
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Power Over X o |
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Overheat X o |
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================ ======= ======= |
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The external event interfaces on the WDT boards are not currently supported. |
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Minor numbers are however allocated for it. |
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Example Watchdog Driver: |
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see samples/watchdog/watchdog-simple.c
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