0001 What: /sys/class/watchdog/watchdogn/bootstatus
0002 Date: August 2015
0003 Contact: Wim Van Sebroeck <wim@iguana.be>
0004 Description:
0005 It is a read only file. It contains status of the watchdog
0006 device at boot. It is equivalent to WDIOC_GETBOOTSTATUS of
0007 ioctl interface.
0008
0009 What: /sys/class/watchdog/watchdogn/identity
0010 Date: August 2015
0011 Contact: Wim Van Sebroeck <wim@iguana.be>
0012 Description:
0013 It is a read only file. It contains identity string of
0014 watchdog device.
0015
0016 What: /sys/class/watchdog/watchdogn/nowayout
0017 Date: August 2015
0018 Contact: Wim Van Sebroeck <wim@iguana.be>
0019 Description:
0020 It is a read/write file. While reading, it gives '1'
0021 if the device has the nowayout feature set, otherwise
0022 it gives '0'. Writing a '1' to the file enables the
0023 nowayout feature. Once set, the nowayout feature
0024 cannot be disabled, so writing a '0' either has no
0025 effect (if the feature was already disabled) or
0026 results in a permission error.
0027
0028 What: /sys/class/watchdog/watchdogn/state
0029 Date: August 2015
0030 Contact: Wim Van Sebroeck <wim@iguana.be>
0031 Description:
0032 It is a read only file. It gives active/inactive status of
0033 watchdog device.
0034
0035 What: /sys/class/watchdog/watchdogn/status
0036 Date: August 2015
0037 Contact: Wim Van Sebroeck <wim@iguana.be>
0038 Description:
0039 It is a read only file. It contains watchdog device's
0040 internal status bits. It is equivalent to WDIOC_GETSTATUS
0041 of ioctl interface.
0042
0043 What: /sys/class/watchdog/watchdogn/timeleft
0044 Date: August 2015
0045 Contact: Wim Van Sebroeck <wim@iguana.be>
0046 Description:
0047 It is a read only file. It contains value of time left for
0048 reset generation. It is equivalent to WDIOC_GETTIMELEFT of
0049 ioctl interface.
0050
0051 What: /sys/class/watchdog/watchdogn/timeout
0052 Date: August 2015
0053 Contact: Wim Van Sebroeck <wim@iguana.be>
0054 Description:
0055 It is a read only file. It is read to know about current
0056 value of timeout programmed.
0057
0058 What: /sys/class/watchdog/watchdogn/pretimeout
0059 Date: December 2016
0060 Contact: Wim Van Sebroeck <wim@iguana.be>
0061 Description:
0062 It is a read only file. It specifies the time in seconds before
0063 timeout when the pretimeout interrupt is delivered. Pretimeout
0064 is an optional feature.
0065
0066 What: /sys/class/watchdog/watchdogn/pretimeout_avaialable_governors
0067 Date: February 2017
0068 Contact: Wim Van Sebroeck <wim@iguana.be>
0069 Description:
0070 It is a read only file. It shows the pretimeout governors
0071 available for this watchdog.
0072
0073 What: /sys/class/watchdog/watchdogn/pretimeout_governor
0074 Date: February 2017
0075 Contact: Wim Van Sebroeck <wim@iguana.be>
0076 Description:
0077 It is a read/write file. When read, the currently assigned
0078 pretimeout governor is returned. When written, it sets
0079 the pretimeout governor.
0080
0081 What: /sys/class/watchdog/watchdog1/access_cs0
0082 Date: August 2019
0083 Contact: Ivan Mikhaylov <i.mikhaylov@yadro.com>,
0084 Alexander Amelkin <a.amelkin@yadro.com>
0085 Description:
0086 It is a read/write file. This attribute exists only if the
0087 system has booted from the alternate flash chip due to
0088 expiration of a watchdog timer of AST2400/AST2500 when
0089 alternate boot function was enabled with 'aspeed,alt-boot'
0090 devicetree option for that watchdog or with an appropriate
0091 h/w strapping (for WDT2 only).
0092
0093 At alternate flash the 'access_cs0' sysfs node provides:
0094
0095 ast2400:
0096 a way to get access to the primary SPI flash
0097 chip at CS0 after booting from the alternate
0098 chip at CS1.
0099 ast2500:
0100 a way to restore the normal address mapping
0101 from (CS0->CS1, CS1->CS0) to (CS0->CS0,
0102 CS1->CS1).
0103
0104 Clearing the boot code selection and timeout counter also
0105 resets to the initial state the chip select line mapping. When
0106 the SoC is in normal mapping state (i.e. booted from CS0),
0107 clearing those bits does nothing for both versions of the SoC.
0108 For alternate boot mode (booted from CS1 due to wdt2
0109 expiration) the behavior differs as described above.
0110
0111 This option can be used with wdt2 (watchdog1) only.
0112
0113 When read, the current status of the boot code selection is
0114 shown. When written with any non-zero value, it clears
0115 the boot code selection and the timeout counter, which results
0116 in chipselect reset for AST2400/AST2500.
