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| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-watchdog | 116 |
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diff --git a/Documentation/ABI/testing/sysfs-class-watchdog b/Documentation/ABI/testing/sysfs-class-watchdog new file mode 100644 index 000000000..585caecda --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-watchdog @@ -0,0 +1,116 @@ +What: /sys/class/watchdog/watchdogn/bootstatus +Date: August 2015 +Contact: Wim Van Sebroeck <wim@iguana.be> +Description: + It is a read only file. It contains status of the watchdog + device at boot. It is equivalent to WDIOC_GETBOOTSTATUS of + ioctl interface. + +What: /sys/class/watchdog/watchdogn/identity +Date: August 2015 +Contact: Wim Van Sebroeck <wim@iguana.be> +Description: + It is a read only file. It contains identity string of + watchdog device. + +What: /sys/class/watchdog/watchdogn/nowayout +Date: August 2015 +Contact: Wim Van Sebroeck <wim@iguana.be> +Description: + It is a read/write file. While reading, it gives '1' + if the device has the nowayout feature set, otherwise + it gives '0'. Writing a '1' to the file enables the + nowayout feature. Once set, the nowayout feature + cannot be disabled, so writing a '0' either has no + effect (if the feature was already disabled) or + results in a permission error. + +What: /sys/class/watchdog/watchdogn/state +Date: August 2015 +Contact: Wim Van Sebroeck <wim@iguana.be> +Description: + It is a read only file. It gives active/inactive status of + watchdog device. + +What: /sys/class/watchdog/watchdogn/status +Date: August 2015 +Contact: Wim Van Sebroeck <wim@iguana.be> +Description: + It is a read only file. It contains watchdog device's + internal status bits. It is equivalent to WDIOC_GETSTATUS + of ioctl interface. + +What: /sys/class/watchdog/watchdogn/timeleft +Date: August 2015 +Contact: Wim Van Sebroeck <wim@iguana.be> +Description: + It is a read only file. It contains value of time left for + reset generation. It is equivalent to WDIOC_GETTIMELEFT of + ioctl interface. + +What: /sys/class/watchdog/watchdogn/timeout +Date: August 2015 +Contact: Wim Van Sebroeck <wim@iguana.be> +Description: + It is a read only file. It is read to know about current + value of timeout programmed. + +What: /sys/class/watchdog/watchdogn/pretimeout +Date: December 2016 +Contact: Wim Van Sebroeck <wim@iguana.be> +Description: + It is a read only file. It specifies the time in seconds before + timeout when the pretimeout interrupt is delivered. Pretimeout + is an optional feature. + +What: /sys/class/watchdog/watchdogn/pretimeout_avaialable_governors +Date: February 2017 +Contact: Wim Van Sebroeck <wim@iguana.be> +Description: + It is a read only file. It shows the pretimeout governors + available for this watchdog. + +What: /sys/class/watchdog/watchdogn/pretimeout_governor +Date: February 2017 +Contact: Wim Van Sebroeck <wim@iguana.be> +Description: + It is a read/write file. When read, the currently assigned + pretimeout governor is returned. When written, it sets + the pretimeout governor. + +What: /sys/class/watchdog/watchdog1/access_cs0 +Date: August 2019 +Contact: Ivan Mikhaylov <i.mikhaylov@yadro.com>, + Alexander Amelkin <a.amelkin@yadro.com> +Description: + It is a read/write file. This attribute exists only if the + system has booted from the alternate flash chip due to + expiration of a watchdog timer of AST2400/AST2500 when + alternate boot function was enabled with 'aspeed,alt-boot' + devicetree option for that watchdog or with an appropriate + h/w strapping (for WDT2 only). + + At alternate flash the 'access_cs0' sysfs node provides: + + ast2400: + a way to get access to the primary SPI flash + chip at CS0 after booting from the alternate + chip at CS1. + ast2500: + a way to restore the normal address mapping + from (CS0->CS1, CS1->CS0) to (CS0->CS0, + CS1->CS1). + + Clearing the boot code selection and timeout counter also + resets to the initial state the chip select line mapping. When + the SoC is in normal mapping state (i.e. booted from CS0), + clearing those bits does nothing for both versions of the SoC. + For alternate boot mode (booted from CS1 due to wdt2 + expiration) the behavior differs as described above. + + This option can be used with wdt2 (watchdog1) only. + + When read, the current status of the boot code selection is + shown. When written with any non-zero value, it clears + the boot code selection and the timeout counter, which results + in chipselect reset for AST2400/AST2500. |