summaryrefslogtreecommitdiffstats
path: root/Documentation/ABI/testing/sysfs-class-watchdog
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--Documentation/ABI/testing/sysfs-class-watchdog116
1 files changed, 116 insertions, 0 deletions
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.