From: Fu Wei fu.wei@linaro.org

The sbsa-gwdt.txt documentation in devicetree/bindings/watchdog is for introducing SBSA(Server Base System Architecture) Generic Watchdog device node info into FDT.

Acked-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Fu Wei fu.wei@linaro.org --- .../devicetree/bindings/watchdog/sbsa-gwdt.txt | 36 ++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt

diff --git a/Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt b/Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt new file mode 100644 index 0000000..010e5c4 --- /dev/null +++ b/Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt @@ -0,0 +1,36 @@ +* SBSA(Server Base System Architecture) Generic Watchdog + +The SBSA Generic Watchdog Timer is used for resetting the system after +two stages of timeout. +More details: ARM-DEN-0029 - Server Base System Architecture (SBSA) + +Required properties: +- compatible : Should at least contain "arm,sbsa-gwdt". + +- reg : base physical address of the frames and length of memory mapped region. + +- reg-names : Should contain the resource reg names to show the order of + the values in "reg". + Must include the following entries : "refresh", "control". + +- interrupts : Should at least contain WS0 interrupt, + the WS1 Signal is optional. + +- interrupt-names : Should contain the resource interrupt names. + Must include the following entries : "ws0". "ws1" is optional. + +Optional properties +- timeout-sec : Watchdog pre-timeout and timeout values (in seconds). + The first is timeout values, then pre-timeout. + +Example for FVP Foundation Model v8: + +watchdog@2a440000 { + compatible = "arm,sbsa-gwdt"; + reg = <0x0 0x2a440000 0 0x1000>, + <0x0 0x2a450000 0 0x1000>; + reg-names = "control", "refresh"; + interrupts = <0 27 4>; + interrupt-names = "ws0"; + timeout-sec = <10 5>; +};

From: Fu Wei fu.wei@linaro.org

This can be a example of adding SBSA Generic Watchdog device node into some dts files for the Soc which contains SBSA Generic Watchdog.

Acked-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Fu Wei fu.wei@linaro.org --- arch/arm64/boot/dts/arm/foundation-v8.dts | 10 ++++++++++ 1 file changed, 10 insertions(+)

diff --git a/arch/arm64/boot/dts/arm/foundation-v8.dts b/arch/arm64/boot/dts/arm/foundation-v8.dts index 4eac8dc..7b80203 100644 --- a/arch/arm64/boot/dts/arm/foundation-v8.dts +++ b/arch/arm64/boot/dts/arm/foundation-v8.dts @@ -237,4 +237,14 @@ }; }; }; + watchdog@2a440000 { + compatible = "arm,sbsa-gwdt"; + reg = <0x0 0x2a440000 0 0x1000>, + <0x0 0x2a450000 0 0x1000>; + reg-names = "control", + "refresh"; + interrupts = <0 27 4>; + interrupt-names = "ws0"; + timeout-sec = <10 5>; + }; };

From: Fu Wei fu.wei@linaro.org

Also update Documentation/watchdog/watchdog-kernel-api.txt to introduce: (1)the new elements in the watchdog_device and watchdog_ops struct; (2)the new API "watchdog_init_timeouts"

Reasons: (1)kernel already has two watchdog drivers are using "pretimeout": drivers/char/ipmi/ipmi_watchdog.c drivers/watchdog/kempld_wdt.c(but the definition is different) (2)some other drivers are going to use this: ARM SBSA Generic Watchdog

Signed-off-by: Fu Wei fu.wei@linaro.org --- Documentation/watchdog/watchdog-kernel-api.txt | 47 ++++++++++-- drivers/watchdog/watchdog_core.c | 98 ++++++++++++++++++-------- drivers/watchdog/watchdog_dev.c | 53 ++++++++++++++ include/linux/watchdog.h | 39 ++++++++-- 4 files changed, 200 insertions(+), 37 deletions(-)

diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt index a0438f3..d1b1238 100644 --- a/Documentation/watchdog/watchdog-kernel-api.txt +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -49,6 +49,9 @@ struct watchdog_device { unsigned int timeout; unsigned int min_timeout; unsigned int max_timeout; + unsigned int pretimeout; + unsigned int min_pretimeout; + unsigned int max_pretimeout; void *driver_data; struct mutex lock; unsigned long status; @@ -70,6 +73,9 @@ It contains following fields: * 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). +* pretimeout: the watchdog timer's pretimeout value (in seconds). +* min_pretimeout: the watchdog timer's minimum pretimeout value (in seconds). +* max_pretimeout: the watchdog timer's maximum pretimeout value (in seconds). * 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. @@ -92,6 +98,7 @@ struct watchdog_ops { int (*ping)(struct watchdog_device *); unsigned int (*status)(struct watchdog_device *); int (*set_timeout)(struct watchdog_device *, unsigned int); + int (*set_pretimeout)(struct watchdog_device *, unsigned int); unsigned int (*get_timeleft)(struct watchdog_device *); void (*ref)(struct watchdog_device *); void (*unref)(struct watchdog_device *); @@ -153,9 +160,19 @@ they are supported. These optional routines/operations are: and -EIO for "could not write value to the watchdog". On success this routine should set the timeout value of the watchdog_device to the achieved timeout value (which may be different from the requested one - because the watchdog does not necessarily has a 1 second resolution). + because the watchdog does not necessarily has a 1 second resolution; + If the driver supports pretimeout, then the timeout value must be greater + than that). (Note: the WDIOF_SETTIMEOUT needs to be set in the options field of the watchdog's info structure). +* set_pretimeout: this routine checks and changes the pretimeout of the + watchdog timer device. It returns 0 on success, -EINVAL for "parameter out of + range" and -EIO for "could not write value to the watchdog". On success this + routine should set the pretimeout value of the watchdog_device to the + achieved pretimeout value (which may be different from the requested one + because the watchdog does not necessarily has a 1 second resolution). + (Note: the WDIOF_PRETIMEOUT 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. @@ -219,8 +236,28 @@ extern int watchdog_init_timeout(struct watchdog_device *wdd, unsigned int timeout_parm, struct device *dev);

The watchdog_init_timeout function allows you to initialize the timeout field -using the module timeout parameter or by retrieving the timeout-sec property from -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. +using the module timeout parameter or by retrieving the first element of +the timeout-sec property from 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. + +Some watchdog timers have two stage of timeouts (timeout and pretimeout), +to initialize the timeout and pretimeout fields at the same time, the following +function can be used: + +int watchdog_init_timeouts(struct watchdog_device *wdd, + unsigned int pretimeout_parm, + unsigned int timeout_parm, + struct device *dev); + +The watchdog_init_timeouts function allows you to initialize the pretimeout and +timeout fields using the module pretimeout and timeout parameter or by +retrieving the elements in the timeout-sec property (the first element is for +timeout, the second one is for pretimeout) from the device tree (if the module +pretimeout and timeout parameter are invalid). +Best practice is to set the default pretimeout and timeout value as pretimeout +and timeout value in the watchdog_device and then use this function to set the +user "preferred" pretimeout value. This routine returns zero on success and a negative errno code for failure. diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c index cec9b55..a45e8bb 100644 --- a/drivers/watchdog/watchdog_core.c +++ b/drivers/watchdog/watchdog_core.c @@ -46,57 +46,99 @@ static struct class *watchdog_class; static void watchdog_check_min_max_timeout(struct watchdog_device *wdd) { /* - * Check that we have valid min and max timeout values, if - * not reset them both to 0 (=not used or unknown) + * Check that we have valid min and max pretimeout and timeout values, + * if not, reset them all to 0 (=not used or unknown) */ - if (wdd->min_timeout > wdd->max_timeout) { - pr_info("Invalid min and max timeout values, resetting to 0!\n"); + if (wdd->min_pretimeout > wdd->max_pretimeout || + wdd->min_timeout > wdd->max_timeout || + wdd->min_timeout < wdd->min_pretimeout || + wdd->max_timeout < wdd->max_pretimeout) { + pr_info("Invalid min or max timeouts, resetting to 0\n"); + wdd->min_pretimeout = 0; + wdd->max_pretimeout = 0; wdd->min_timeout = 0; wdd->max_timeout = 0; } }

/** - * watchdog_init_timeout() - initialize the timeout field + * watchdog_init_timeouts() - initialize the pretimeout and timeout field + * @pretimeout_parm: pretimeout module parameter * @timeout_parm: timeout module parameter * @dev: Device that stores the timeout-sec property * - * Initialize the timeout field of the watchdog_device struct with either the - * timeout module parameter (if it is valid value) or the timeout-sec property - * (only if it is a valid value and the timeout_parm is out of bounds). - * If none of them are valid then we keep the old value (which should normally - * be the default timeout value. + * Initialize the pretimeout and timeout field of the watchdog_device struct + * with both the pretimeout and timeout module parameters (if they are valid) or + * the timeout-sec property (only if they are valid and the pretimeout_parm or + * timeout_parm is out of bounds). If one of them is invalid, then we keep + * the old value (which should normally be the default timeout value). * * A zero is returned on success and -EINVAL for failure. */ -int watchdog_init_timeout(struct watchdog_device *wdd, - unsigned int timeout_parm, struct device *dev) +int watchdog_init_timeouts(struct watchdog_device *wdd, + unsigned int pretimeout_parm, + unsigned int timeout_parm, + struct device *dev) { - unsigned int t = 0; - int ret = 0; + int ret = 0, length = 0; + u32 timeouts[2] = {0}; + struct property *prop;

watchdog_check_min_max_timeout(wdd);

- /* try to get the timeout module parameter first */ - if (!watchdog_timeout_invalid(wdd, timeout_parm) && timeout_parm) { - wdd->timeout = timeout_parm; - return ret; - } - if (timeout_parm) + /* + * Try to get the pretimeout module parameter first. + * Note: zero is a valid value for pretimeout. + */ + if (watchdog_pretimeout_invalid(wdd, pretimeout_parm)) + ret = -EINVAL; + + /* + * Try to get the timeout module parameter, + * if it's valid and pretimeout is valid(ret == 0), + * assignment and return zero. Otherwise, try dtb. + */ + if (timeout_parm && !ret) { + if (!watchdog_timeout_invalid(wdd, timeout_parm)) { + wdd->timeout = timeout_parm; + wdd->pretimeout = pretimeout_parm; + return 0; + } ret = -EINVAL; + }

- /* try to get the timeout_sec property */ + /* + * Either at least one of the module parameters is invalid, + * or timeout_parm is 0. Try to get the timeout_sec property. + */ if (dev == NULL || dev->of_node == NULL) return ret; - of_property_read_u32(dev->of_node, "timeout-sec", &t); - if (!watchdog_timeout_invalid(wdd, t) && t) - wdd->timeout = t; - else - ret = -EINVAL;

- return ret; + prop = of_find_property(dev->of_node, "timeout-sec", &length); + if (prop && length > 0 && length <= sizeof(u32) * 2) { + of_property_read_u32_array(dev->of_node, + "timeout-sec", timeouts, + length / sizeof(u32)); + if (length == sizeof(u32) * 2) { + if (watchdog_pretimeout_invalid(wdd, timeouts[1])) + return -EINVAL; + ret = 0; + } else { + ret = -EINVAL; + } + + if (!watchdog_timeout_invalid(wdd, timeouts[0]) && + timeouts[0]) { + wdd->timeout = timeouts[0]; + if (!ret) + wdd->pretimeout = timeouts[1]; + return 0; + } + } + + return -EINVAL; } -EXPORT_SYMBOL_GPL(watchdog_init_timeout); +EXPORT_SYMBOL_GPL(watchdog_init_timeouts);

/** * watchdog_register_device() - register a watchdog device diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 6aaefba..af0777e 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -218,6 +218,38 @@ out_timeout: }

/* + * watchdog_set_pretimeout: set the watchdog timer pretimeout + * @wddev: the watchdog device to set the timeout for + * @pretimeout: pretimeout to set in seconds + */ + +static int watchdog_set_pretimeout(struct watchdog_device *wddev, + unsigned int pretimeout) +{ + int err; + + if (!wddev->ops->set_pretimeout || + !(wddev->info->options & WDIOF_PRETIMEOUT)) + return -EOPNOTSUPP; + + if (watchdog_pretimeout_invalid(wddev, pretimeout)) + return -EINVAL; + + mutex_lock(&wddev->lock); + + if (test_bit(WDOG_UNREGISTERED, &wddev->status)) { + err = -ENODEV; + goto out_pretimeout; + } + + err = wddev->ops->set_pretimeout(wddev, pretimeout); + +out_pretimeout: + mutex_unlock(&wddev->lock); + return err; +} + +/* * watchdog_get_timeleft: wrapper to get the time left before a reboot * @wddev: the watchdog device to get the remaining time from * @timeleft: the time that's left @@ -388,6 +420,27 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd, if (wdd->timeout == 0) return -EOPNOTSUPP; return put_user(wdd->timeout, p); + case WDIOC_SETPRETIMEOUT: + /* check if we support the pretimeout */ + if (!(wdd->info->options & WDIOF_PRETIMEOUT)) + return -EOPNOTSUPP; + if (get_user(val, p)) + return -EFAULT; + err = watchdog_set_pretimeout(wdd, val); + if (err < 0) + return err; + /* + * If the watchdog is active then we send a keepalive ping + * to make sure that the watchdog keeps running (and if + * possible that it takes the new pretimeout) + */ + watchdog_ping(wdd); + /* Fall */ + case WDIOC_GETPRETIMEOUT: + /* check if we support the pretimeout */ + if (wdd->info->options & WDIOF_PRETIMEOUT) + return put_user(wdd->pretimeout, p); + return -EOPNOTSUPP; case WDIOC_GETTIMELEFT: err = watchdog_get_timeleft(wdd, &val); if (err) diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index a746bf5..47a87cb 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -25,6 +25,7 @@ struct watchdog_device; * @ping: The routine that sends a keepalive ping to the watchdog device. * @status: The routine that shows the status of the watchdog device. * @set_timeout:The routine for setting the watchdog devices timeout value. + * @set_pretimeout:The routine for setting the watchdog devices pretimeout value * @get_timeleft:The routine that get's the time that's left before a reset. * @ref: The ref operation for dyn. allocated watchdog_device structs * @unref: The unref operation for dyn. allocated watchdog_device structs @@ -44,6 +45,7 @@ struct watchdog_ops { int (*ping)(struct watchdog_device *); unsigned int (*status)(struct watchdog_device *); int (*set_timeout)(struct watchdog_device *, unsigned int); + int (*set_pretimeout)(struct watchdog_device *, unsigned int); unsigned int (*get_timeleft)(struct watchdog_device *); void (*ref)(struct watchdog_device *); void (*unref)(struct watchdog_device *); @@ -62,6 +64,9 @@ struct watchdog_ops { * @timeout: The watchdog devices timeout value. * @min_timeout:The watchdog devices minimum timeout value. * @max_timeout:The watchdog devices maximum timeout value. + * @pretimeout: The watchdog devices pretimeout value. + * @min_pretimeout:The watchdog devices minimum pretimeout value. + * @max_pretimeout:The watchdog devices maximum pretimeout value. * @driver-data:Pointer to the drivers private data. * @lock: Lock for watchdog core internal use only. * @status: Field that contains the devices internal status bits. @@ -86,6 +91,9 @@ struct watchdog_device { unsigned int timeout; unsigned int min_timeout; unsigned int max_timeout; + unsigned int pretimeout; + unsigned int min_pretimeout; + unsigned int max_pretimeout; void *driver_data; struct mutex lock; unsigned long status; @@ -116,8 +124,22 @@ static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool noway /* Use the following function to check if a timeout value is invalid */ static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t) { - return ((wdd->max_timeout != 0) && - (t < wdd->min_timeout || t > wdd->max_timeout)); + return (wdd->max_timeout && + (t < wdd->min_timeout || t > wdd->max_timeout)) || + (wdd->pretimeout && t <= wdd->pretimeout); +} + +/* + * Use the following function to check if a pretimeout value is invalid. + * It can be "0", that means we don't use pretimeout. + * This function returns false, when pretimeout is 0. + */ +static inline bool watchdog_pretimeout_invalid(struct watchdog_device *wdd, + unsigned int t) +{ + return t && ((wdd->max_pretimeout && + (t < wdd->min_pretimeout || t > wdd->max_pretimeout)) || + (wdd->timeout && t >= wdd->timeout)); }

/* Use the following functions to manipulate watchdog driver specific data */ @@ -132,8 +154,17 @@ static inline void *watchdog_get_drvdata(struct watchdog_device *wdd) }

/* drivers/watchdog/watchdog_core.c */ -extern int watchdog_init_timeout(struct watchdog_device *wdd, - unsigned int timeout_parm, struct device *dev); +int watchdog_init_timeouts(struct watchdog_device *wdd, + unsigned int pretimeout_parm, + unsigned int timeout_parm, + struct device *dev); +static inline int watchdog_init_timeout(struct watchdog_device *wdd, + unsigned int timeout_parm, + struct device *dev) +{ + return watchdog_init_timeouts(wdd, 0, timeout_parm, dev); +} + extern int watchdog_register_device(struct watchdog_device *); extern void watchdog_unregister_device(struct watchdog_device *);