diff options
Diffstat (limited to 'Documentation')
7 files changed, 197 insertions, 40 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-watchdog b/Documentation/ABI/testing/sysfs-class-watchdog new file mode 100644 index 000000000000..736046b33040 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-watchdog @@ -0,0 +1,51 @@ +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 only file. While reading, it gives '1' if that + device supports nowayout feature else, it gives '0'. + +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. diff --git a/Documentation/devicetree/bindings/watchdog/alphascale-asm9260.txt b/Documentation/devicetree/bindings/watchdog/alphascale-asm9260.txt new file mode 100644 index 000000000000..75b265a04047 --- /dev/null +++ b/Documentation/devicetree/bindings/watchdog/alphascale-asm9260.txt @@ -0,0 +1,35 @@ +Alphascale asm9260 Watchdog timer + +Required properties: + +- compatible : should be "alphascale,asm9260-wdt". +- reg : Specifies base physical address and size of the registers. +- clocks : the clocks feeding the watchdog timer. See clock-bindings.txt +- clock-names : should be set to + "mod" - source for tick counter. + "ahb" - ahb gate. +- resets : phandle pointing to the system reset controller with + line index for the watchdog. +- reset-names : should be set to "wdt_rst". + +Optional properties: +- timeout-sec : shall contain the default watchdog timeout in seconds, + if unset, the default timeout is 30 seconds. +- alphascale,mode : three modes are supported + "hw" - hw reset (default). + "sw" - sw reset. + "debug" - no action is taken. + +Example: + +watchdog0: watchdog@80048000 { + compatible = "alphascale,asm9260-wdt"; + reg = <0x80048000 0x10>; + clocks = <&acc CLKID_SYS_WDT>, <&acc CLKID_AHB_WDT>; + clock-names = "mod", "ahb"; + interrupts = <55>; + resets = <&rst WDT_RESET>; + reset-names = "wdt_rst"; + timeout-sec = <30>; + alphascale,mode = "hw"; +}; diff --git a/Documentation/devicetree/bindings/watchdog/mt7621-wdt.txt b/Documentation/devicetree/bindings/watchdog/mt7621-wdt.txt new file mode 100644 index 000000000000..c15ef0ef609f --- /dev/null +++ b/Documentation/devicetree/bindings/watchdog/mt7621-wdt.txt @@ -0,0 +1,12 @@ +Ralink Watchdog Timers + +Required properties: +- compatible: must be "mediatek,mt7621-wdt" +- reg: physical base address of the controller and length of the register range + +Example: + + watchdog@100 { + compatible = "mediatek,mt7621-wdt"; + reg = <0x100 0x10>; + }; diff --git a/Documentation/devicetree/bindings/watchdog/sigma,smp8642-wdt.txt b/Documentation/devicetree/bindings/watchdog/sigma,smp8642-wdt.txt new file mode 100644 index 000000000000..5b7ec2c707d8 --- /dev/null +++ b/Documentation/devicetree/bindings/watchdog/sigma,smp8642-wdt.txt @@ -0,0 +1,18 @@ +Sigma Designs SMP86xx/SMP87xx watchdog + +Required properties: +- compatible: Should be "sigma,smp8642-wdt" +- reg: Specifies the physical address region +- clocks: Should be a phandle to the clock + +Optional properties: +- timeout-sec: watchdog timeout in seconds + +Example: + +watchdog@1fd00 { + compatible = "sigma,smp8642-wdt"; + reg = <0x1fd00 8>; + clocks = <&xtal_in_clk>; + timeout-sec = <30>; +}; diff --git a/Documentation/devicetree/bindings/watchdog/ts4800-wdt.txt b/Documentation/devicetree/bindings/watchdog/ts4800-wdt.txt new file mode 100644 index 000000000000..8f6caad4258d --- /dev/null +++ b/Documentation/devicetree/bindings/watchdog/ts4800-wdt.txt @@ -0,0 +1,25 @@ +Technologic Systems Watchdog + +Required properties: +- compatible: must be "technologic,ts4800-wdt" +- syscon: phandle / integer array that points to the syscon node which + describes the FPGA's syscon registers. + - phandle to FPGA's syscon + - offset to the watchdog register + +Optional property: +- timeout-sec: contains the watchdog timeout in seconds. + +Example: + +syscon: syscon@b0010000 { + compatible = "syscon", "simple-mfd"; + reg = <0xb0010000 0x3d>; + reg-io-width = <2>; + + wdt@e { + compatible = "technologic,ts4800-wdt"; + syscon = <&syscon 0xe>; + timeout-sec = <10>; + }; +} diff --git a/Documentation/devicetree/bindings/watchdog/ziirave-wdt.txt b/Documentation/devicetree/bindings/watchdog/ziirave-wdt.txt new file mode 100644 index 000000000000..3d878184ec3f --- /dev/null +++ b/Documentation/devicetree/bindings/watchdog/ziirave-wdt.txt @@ -0,0 +1,19 @@ +Zodiac RAVE Watchdog Timer + +Required properties: +- compatible: must be "zii,rave-wdt" +- reg: i2c slave address of device, usually 0x38 + +Optional Properties: +- timeout-sec: Watchdog timeout value in seconds. +- reset-duration-ms: Duration of the pulse generated when the watchdog times + out. Value in milliseconds. + +Example: + + watchdog@38 { + compatible = "zii,rave-wdt"; + reg = <0x38>; + timeout-sec = <30>; + reset-duration-ms = <30>; + }; diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt index d8b0d3367706..55120a055a14 100644 --- a/Documentation/watchdog/watchdog-kernel-api.txt +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -44,17 +44,18 @@ The watchdog device structure looks like this: struct watchdog_device { int id; - struct cdev cdev; - struct device *dev; struct device *parent; + const struct attribute_group **groups; const struct watchdog_info *info; const struct watchdog_ops *ops; unsigned int bootstatus; unsigned int timeout; unsigned int min_timeout; unsigned int max_timeout; + struct notifier_block reboot_nb; + struct notifier_block restart_nb; void *driver_data; - struct mutex lock; + struct watchdog_core_data *wd_data; unsigned long status; struct list_head deferred; }; @@ -64,27 +65,32 @@ It contains following fields: /dev/watchdog0 cdev (dynamic major, minor 0) as well as the old /dev/watchdog miscdev. The id is set automatically when calling watchdog_register_device. -* cdev: cdev for the dynamic /dev/watchdog<id> device nodes. This - field is also populated by watchdog_register_device. -* dev: device under the watchdog class (created by watchdog_register_device). * parent: set this to the parent device (or NULL) before calling watchdog_register_device. +* groups: List of sysfs attribute groups to create when creating the watchdog + device. * info: a pointer to a watchdog_info structure. This structure gives some additional information about the watchdog timer itself. (Like it's unique name) * ops: a pointer to the list of watchdog operations that the watchdog supports. * timeout: the watchdog timer's timeout value (in seconds). * min_timeout: the watchdog timer's minimum timeout value (in seconds). * max_timeout: the watchdog timer's maximum timeout value (in seconds). +* reboot_nb: notifier block that is registered for reboot notifications, for + internal use only. If the driver calls watchdog_stop_on_reboot, watchdog core + will stop the watchdog on such notifications. +* restart_nb: notifier block that is registered for machine restart, for + internal use only. If a watchdog is capable of restarting the machine, it + should define ops->restart. Priority can be changed through + watchdog_set_restart_priority. * bootstatus: status of the device after booting (reported with watchdog WDIOF_* status bits). * driver_data: a pointer to the drivers private data of a watchdog device. This data should only be accessed via the watchdog_set_drvdata and watchdog_get_drvdata routines. -* lock: Mutex for WatchDog Timer Driver Core internal use only. +* wd_data: a pointer to watchdog core internal data. * status: this field contains a number of status bits that give extra information about the status of the device (Like: is the watchdog timer - running/active, is the nowayout bit set, is the device opened via - the /dev/watchdog interface or not, ...). + running/active, or is the nowayout bit set). * deferred: entry in wtd_deferred_reg_list which is used to register early initialized watchdogs. @@ -100,8 +106,9 @@ struct watchdog_ops { unsigned int (*status)(struct watchdog_device *); int (*set_timeout)(struct watchdog_device *, unsigned int); unsigned int (*get_timeleft)(struct watchdog_device *); - void (*ref)(struct watchdog_device *); - void (*unref)(struct watchdog_device *); + int (*restart)(struct watchdog_device *); + void (*ref)(struct watchdog_device *) __deprecated; + void (*unref)(struct watchdog_device *) __deprecated; long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long); }; @@ -110,20 +117,6 @@ driver's operations. This module owner will be used to lock the module when the watchdog is active. (This to avoid a system crash when you unload the module and /dev/watchdog is still open). -If the watchdog_device struct is dynamically allocated, just locking the module -is not enough and a driver also needs to define the ref and unref operations to -ensure the structure holding the watchdog_device does not go away. - -The simplest (and usually sufficient) implementation of this is to: -1) Add a kref struct to the same structure which is holding the watchdog_device -2) Define a release callback for the kref which frees the struct holding both -3) Call kref_init on this kref *before* calling watchdog_register_device() -4) Define a ref operation calling kref_get on this kref -5) Define a unref operation calling kref_put on this kref -6) When it is time to cleanup: - * Do not kfree() the struct holding both, the last kref_put will do this! - * *After* calling watchdog_unregister_device() call kref_put on the kref - Some operations are mandatory and some are optional. The mandatory operations are: * start: this is a pointer to the routine that starts the watchdog timer @@ -164,34 +157,23 @@ they are supported. These optional routines/operations are: (Note: the WDIOF_SETTIMEOUT needs to be set in the options field of the watchdog's info structure). * get_timeleft: this routines returns the time that's left before a reset. -* ref: the operation that calls kref_get on the kref of a dynamically - allocated watchdog_device struct. -* unref: the operation that calls kref_put on the kref of a dynamically - allocated watchdog_device struct. +* restart: this routine restarts the machine. It returns 0 on success or a + negative errno code for failure. * ioctl: if this routine is present then it will be called first before we do our own internal ioctl call handling. This routine should return -ENOIOCTLCMD if a command is not supported. The parameters that are passed to the ioctl call are: watchdog_device, cmd and arg. +The 'ref' and 'unref' operations are no longer used and deprecated. + The status bits should (preferably) be set with the set_bit and clear_bit alike bit-operations. The status bits that are defined are: * WDOG_ACTIVE: this status bit indicates whether or not a watchdog timer device is active or not. When the watchdog is active after booting, then you should set this status bit (Note: when you register the watchdog timer device with this bit set, then opening /dev/watchdog will skip the start operation) -* WDOG_DEV_OPEN: this status bit shows whether or not the watchdog device - was opened via /dev/watchdog. - (This bit should only be used by the WatchDog Timer Driver Core). -* WDOG_ALLOW_RELEASE: this bit stores whether or not the magic close character - has been sent (so that we can support the magic close feature). - (This bit should only be used by the WatchDog Timer Driver Core). * WDOG_NO_WAY_OUT: this bit stores the nowayout setting for the watchdog. If this bit is set then the watchdog timer will not be able to stop. -* WDOG_UNREGISTERED: this bit gets set by the WatchDog Timer Driver Core - after calling watchdog_unregister_device, and then checked before calling - any watchdog_ops, so that you can be sure that no operations (other then - unref) will get called after unregister, even if userspace still holds a - reference to /dev/watchdog To set the WDOG_NO_WAY_OUT status bit (before registering your watchdog timer device) you can either: @@ -231,3 +213,18 @@ the device tree (if the module timeout parameter is invalid). Best practice is to set the default timeout value as timeout value in the watchdog_device and then use this function to set the user "preferred" timeout value. This routine returns zero on success and a negative errno code for failure. + +To disable the watchdog on reboot, the user must call the following helper: + +static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd); + +To change the priority of the restart handler the following helper should be +used: + +void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority); + +User should follow the following guidelines for setting the priority: +* 0: should be called in last resort, has limited restart capabilities +* 128: default restart handler, use if no other handler is expected to be + available, and/or if restart is sufficient to restart the entire system +* 255: highest priority, will preempt all other restart handlers |