From 70f3997667fb127333862977ba4fd3e855fbf617 Mon Sep 17 00:00:00 2001 From: Kyle Roeschley Date: Thu, 25 Feb 2016 11:28:00 -0600 Subject: watchdog: ni903x_wdt: Add NI 903x/913x watchdog driver Add support for the watchdog timer on NI cRIO-903x and cDAQ-913x real- time controllers. Signed-off-by: Jeff Westfahl Signed-off-by: Kyle Roeschley Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- Documentation/watchdog/watchdog-parameters.txt | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation/watchdog') diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt index 9f9ec9f76039..53dfc73e0171 100644 --- a/Documentation/watchdog/watchdog-parameters.txt +++ b/Documentation/watchdog/watchdog-parameters.txt @@ -200,6 +200,11 @@ mv64x60_wdt: nowayout: Watchdog cannot be stopped once started (default=kernel config parameter) ------------------------------------------------- +ni903x_wdt: +timeout: Initial watchdog timeout in seconds (0 Date: Mon, 29 Feb 2016 16:46:47 +0800 Subject: Documentation: add sbsa-gwdt driver documentation The sbsa-gwdt.txt documentation in devicetree/bindings/watchdog is for introducing SBSA(Server Base System Architecture) Generic Watchdog device node info into FDT. Also add sbsa-gwdt introduction in watchdog-parameters.txt Acked-by: Arnd Bergmann Acked-by: Rob Herring Signed-off-by: Fu Wei Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- .../devicetree/bindings/watchdog/sbsa-gwdt.txt | 31 ++++++++++++++++++++++ Documentation/watchdog/watchdog-parameters.txt | 7 +++++ 2 files changed, 38 insertions(+) create mode 100644 Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt (limited to 'Documentation/watchdog') diff --git a/Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt b/Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt new file mode 100644 index 000000000000..6f2d5f91964d --- /dev/null +++ b/Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt @@ -0,0 +1,31 @@ +* SBSA (Server Base System Architecture) Generic Watchdog + +The SBSA Generic Watchdog Timer is used to force a reset of the system +after two stages of timeout have elapsed. A detailed definition of the +watchdog timer can be found in the ARM document: ARM-DEN-0029 - Server +Base System Architecture (SBSA) + +Required properties: +- compatible: Should at least contain "arm,sbsa-gwdt". + +- reg: Each entry specifies the base physical address of a register frame + and the length of that frame; currently, two frames must be defined, + in this order: + 1: Watchdog control frame; + 2: Refresh frame. + +- interrupts: Should contain the Watchdog Signal 0 (WS0) SPI (Shared + Peripheral Interrupt) number of SBSA Generic Watchdog. + +Optional properties +- timeout-sec: Watchdog timeout values (in seconds). + +Example for FVP Foundation Model v8: + +watchdog@2a440000 { + compatible = "arm,sbsa-gwdt"; + reg = <0x0 0x2a440000 0 0x1000>, + <0x0 0x2a450000 0 0x1000>; + interrupts = <0 27 4>; + timeout-sec = <30>; +}; diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt index 53dfc73e0171..beb0ae7bb3e6 100644 --- a/Documentation/watchdog/watchdog-parameters.txt +++ b/Documentation/watchdog/watchdog-parameters.txt @@ -289,6 +289,13 @@ sbc_fitpc2_wdt: margin: Watchdog margin in seconds (default 60s) nowayout: Watchdog cannot be stopped once started ------------------------------------------------- +sbsa_gwdt: +timeout: Watchdog timeout in seconds. (default 10s) +action: Watchdog action at the first stage timeout, + set to 0 to ignore, 1 to panic. (default=0) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- sc1200wdt: isapnp: When set to 0 driver ISA PnP support will be disabled (default=1) io: io port -- cgit v1.2.3-58-ga151 From fb32e9b9deeb5df2913deb7d2ae8c36f4f66ecf3 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Sun, 28 Feb 2016 13:12:14 -0800 Subject: watchdog: Make set_timeout function optional For some watchdogs, the watchdog driver handles timeout changes without explicitly setting any registers. In this situation, the watchdog driver might only set the 'timeout' variable but do nothing else. This can as well be handled by the infrastructure, so make the set_timeout callback optional. If WDIOF_SETTIMEOUT is configured but the .set_timeout callback is not available, update the timeout variable in the infrastructure code. Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- Documentation/watchdog/watchdog-kernel-api.txt | 5 +++++ drivers/watchdog/watchdog_dev.c | 11 +++++++++-- 2 files changed, 14 insertions(+), 2 deletions(-) (limited to 'Documentation/watchdog') diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt index 55120a055a14..dd8f912c0576 100644 --- a/Documentation/watchdog/watchdog-kernel-api.txt +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -156,6 +156,11 @@ they are supported. These optional routines/operations are: because the watchdog does not necessarily has a 1 second resolution). (Note: the WDIOF_SETTIMEOUT needs to be set in the options field of the watchdog's info structure). + If the watchdog driver does not have to perform any action but setting the + watchdog_device.timeout, this callback can be omitted. + If set_timeout is not provided but, WDIOF_SETTIMEOUT is set, the watchdog + infrastructure updates the timeout value of the watchdog_device internally + to the requested value. * get_timeleft: this routines returns the time that's left before a reset. * restart: this routine restarts the machine. It returns 0 on success or a negative errno code for failure. diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index ba2ecce4aae6..b5e700186ae0 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -183,13 +183,20 @@ static unsigned int watchdog_get_status(struct watchdog_device *wdd) static int watchdog_set_timeout(struct watchdog_device *wdd, unsigned int timeout) { - if (!wdd->ops->set_timeout || !(wdd->info->options & WDIOF_SETTIMEOUT)) + int err = 0; + + if (!(wdd->info->options & WDIOF_SETTIMEOUT)) return -EOPNOTSUPP; if (watchdog_timeout_invalid(wdd, timeout)) return -EINVAL; - return wdd->ops->set_timeout(wdd, timeout); + if (wdd->ops->set_timeout) + err = wdd->ops->set_timeout(wdd, timeout); + else + wdd->timeout = timeout; + + return err; } /* -- cgit v1.2.3-58-ga151 From 664a39236e718f9f03fa73fc01006da9ced04efc Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Sun, 28 Feb 2016 13:12:15 -0800 Subject: watchdog: Introduce hardware maximum heartbeat in watchdog core Introduce an optional hardware maximum heartbeat in the watchdog core. The hardware maximum heartbeat can be lower than the maximum timeout. Drivers can set the maximum hardware heartbeat value in the watchdog data structure. If the configured timeout exceeds the maximum hardware heartbeat, the watchdog core enables a timer function to assist sending keepalive requests to the watchdog driver. Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- Documentation/watchdog/watchdog-kernel-api.txt | 19 +++- drivers/watchdog/watchdog_dev.c | 129 +++++++++++++++++++++++-- include/linux/watchdog.h | 28 ++++-- 3 files changed, 158 insertions(+), 18 deletions(-) (limited to 'Documentation/watchdog') diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt index dd8f912c0576..15a02595ade1 100644 --- a/Documentation/watchdog/watchdog-kernel-api.txt +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -52,6 +52,7 @@ struct watchdog_device { unsigned int timeout; unsigned int min_timeout; unsigned int max_timeout; + unsigned int max_hw_heartbeat_ms; struct notifier_block reboot_nb; struct notifier_block restart_nb; void *driver_data; @@ -73,8 +74,18 @@ It contains following fields: 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). + This is the time after which the system will reboot if user space does + not send a heartbeat request if WDOG_ACTIVE is set. * min_timeout: the watchdog timer's minimum timeout value (in seconds). -* max_timeout: the watchdog timer's maximum timeout value (in seconds). + If set, the minimum configurable value for 'timeout'. +* max_timeout: the watchdog timer's maximum timeout value (in seconds), + as seen from userspace. If set, the maximum configurable value for + 'timeout'. Not used if max_hw_heartbeat_ms is non-zero. +* max_hw_heartbeat_ms: Maximum hardware heartbeat, in milli-seconds. + If set, the infrastructure will send heartbeats to the watchdog driver + if 'timeout' is larger than max_hw_heartbeat_ms, unless WDOG_ACTIVE + is set and userspace failed to send a heartbeat for at least 'timeout' + 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. @@ -153,7 +164,11 @@ 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 have a 1 second resolution). + Drivers implementing max_hw_heartbeat_ms set the hardware watchdog heartbeat + to the minimum of timeout and max_hw_heartbeat_ms. Those drivers set the + timeout value of the watchdog_device either to the requested timeout value + (if it is larger than max_hw_heartbeat_ms), or to the achieved timeout value. (Note: the WDIOF_SETTIMEOUT needs to be set in the options field of the watchdog's info structure). If the watchdog driver does not have to perform any action but setting the diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index b5e700186ae0..e668a9e8b648 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -36,6 +36,7 @@ #include /* For the -ENODEV/... values */ #include /* For file operations */ #include /* For __init/__exit/... */ +#include /* For timeout functions */ #include /* For printk/panic/... */ #include /* For data references */ #include /* For handling misc devices */ @@ -44,6 +45,7 @@ #include /* For memory functions */ #include /* For standard types (like size_t) */ #include /* For watchdog specific items */ +#include /* For workqueue */ #include /* For copy_to_user/put_user/... */ #include "watchdog_core.h" @@ -61,6 +63,8 @@ struct watchdog_core_data { struct cdev cdev; struct watchdog_device *wdd; struct mutex lock; + unsigned long last_keepalive; + struct delayed_work work; unsigned long status; /* Internal status bits */ #define _WDOG_DEV_OPEN 0 /* Opened ? */ #define _WDOG_ALLOW_RELEASE 1 /* Did we receive the magic char ? */ @@ -71,6 +75,76 @@ static dev_t watchdog_devt; /* Reference to watchdog device behind /dev/watchdog */ static struct watchdog_core_data *old_wd_data; +static struct workqueue_struct *watchdog_wq; + +static inline bool watchdog_need_worker(struct watchdog_device *wdd) +{ + /* All variables in milli-seconds */ + unsigned int hm = wdd->max_hw_heartbeat_ms; + unsigned int t = wdd->timeout * 1000; + + /* + * A worker to generate heartbeat requests is needed if all of the + * following conditions are true. + * - Userspace activated the watchdog. + * - The driver provided a value for the maximum hardware timeout, and + * thus is aware that the framework supports generating heartbeat + * requests. + * - Userspace requests a longer timeout than the hardware can handle. + */ + return watchdog_active(wdd) && hm && t > hm; +} + +static long watchdog_next_keepalive(struct watchdog_device *wdd) +{ + struct watchdog_core_data *wd_data = wdd->wd_data; + unsigned int timeout_ms = wdd->timeout * 1000; + unsigned long keepalive_interval; + unsigned long last_heartbeat; + unsigned long virt_timeout; + unsigned int hw_heartbeat_ms; + + virt_timeout = wd_data->last_keepalive + msecs_to_jiffies(timeout_ms); + hw_heartbeat_ms = min(timeout_ms, wdd->max_hw_heartbeat_ms); + keepalive_interval = msecs_to_jiffies(hw_heartbeat_ms / 2); + + /* + * To ensure that the watchdog times out wdd->timeout seconds + * after the most recent ping from userspace, the last + * worker ping has to come in hw_heartbeat_ms before this timeout. + */ + last_heartbeat = virt_timeout - msecs_to_jiffies(hw_heartbeat_ms); + return min_t(long, last_heartbeat - jiffies, keepalive_interval); +} + +static inline void watchdog_update_worker(struct watchdog_device *wdd) +{ + struct watchdog_core_data *wd_data = wdd->wd_data; + + if (watchdog_need_worker(wdd)) { + long t = watchdog_next_keepalive(wdd); + + if (t > 0) + mod_delayed_work(watchdog_wq, &wd_data->work, t); + } else { + cancel_delayed_work(&wd_data->work); + } +} + +static int __watchdog_ping(struct watchdog_device *wdd) +{ + int err; + + if (wdd->ops->ping) + err = wdd->ops->ping(wdd); /* ping the watchdog */ + else + err = wdd->ops->start(wdd); /* restart watchdog */ + + watchdog_update_worker(wdd); + + return err; +} + /* * watchdog_ping: ping the watchdog. * @wdd: the watchdog device to ping @@ -85,17 +159,28 @@ static struct watchdog_core_data *old_wd_data; static int watchdog_ping(struct watchdog_device *wdd) { - int err; + struct watchdog_core_data *wd_data = wdd->wd_data; if (!watchdog_active(wdd)) return 0; - if (wdd->ops->ping) - err = wdd->ops->ping(wdd); /* ping the watchdog */ - else - err = wdd->ops->start(wdd); /* restart watchdog */ + wd_data->last_keepalive = jiffies; + return __watchdog_ping(wdd); +} - return err; +static void watchdog_ping_work(struct work_struct *work) +{ + struct watchdog_core_data *wd_data; + struct watchdog_device *wdd; + + wd_data = container_of(to_delayed_work(work), struct watchdog_core_data, + work); + + mutex_lock(&wd_data->lock); + wdd = wd_data->wdd; + if (wdd && watchdog_active(wdd)) + __watchdog_ping(wdd); + mutex_unlock(&wd_data->lock); } /* @@ -111,14 +196,20 @@ static int watchdog_ping(struct watchdog_device *wdd) static int watchdog_start(struct watchdog_device *wdd) { + struct watchdog_core_data *wd_data = wdd->wd_data; + unsigned long started_at; int err; if (watchdog_active(wdd)) return 0; + started_at = jiffies; err = wdd->ops->start(wdd); - if (err == 0) + if (err == 0) { set_bit(WDOG_ACTIVE, &wdd->status); + wd_data->last_keepalive = started_at; + watchdog_update_worker(wdd); + } return err; } @@ -137,6 +228,7 @@ static int watchdog_start(struct watchdog_device *wdd) static int watchdog_stop(struct watchdog_device *wdd) { + struct watchdog_core_data *wd_data = wdd->wd_data; int err; if (!watchdog_active(wdd)) @@ -149,8 +241,10 @@ static int watchdog_stop(struct watchdog_device *wdd) } err = wdd->ops->stop(wdd); - if (err == 0) + if (err == 0) { clear_bit(WDOG_ACTIVE, &wdd->status); + cancel_delayed_work(&wd_data->work); + } return err; } @@ -196,6 +290,8 @@ static int watchdog_set_timeout(struct watchdog_device *wdd, else wdd->timeout = timeout; + watchdog_update_worker(wdd); + return err; } @@ -616,6 +712,8 @@ static int watchdog_release(struct inode *inode, struct file *file) watchdog_ping(wdd); } + cancel_delayed_work_sync(&wd_data->work); + /* make sure that /dev/watchdog can be re-opened */ clear_bit(_WDOG_DEV_OPEN, &wd_data->status); @@ -665,6 +763,11 @@ static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno) wd_data->wdd = wdd; wdd->wd_data = wd_data; + if (!watchdog_wq) + return -ENODEV; + + INIT_DELAYED_WORK(&wd_data->work, watchdog_ping_work); + if (wdd->id == 0) { old_wd_data = wd_data; watchdog_miscdev.parent = wdd->parent; @@ -722,6 +825,8 @@ static void watchdog_cdev_unregister(struct watchdog_device *wdd) wdd->wd_data = NULL; mutex_unlock(&wd_data->lock); + cancel_delayed_work_sync(&wd_data->work); + kref_put(&wd_data->kref, watchdog_core_data_release); } @@ -787,6 +892,13 @@ int __init watchdog_dev_init(void) { int err; + watchdog_wq = alloc_workqueue("watchdogd", + WQ_HIGHPRI | WQ_MEM_RECLAIM, 0); + if (!watchdog_wq) { + pr_err("Failed to create watchdog workqueue\n"); + return -ENOMEM; + } + err = class_register(&watchdog_class); if (err < 0) { pr_err("couldn't register class\n"); @@ -813,4 +925,5 @@ void __exit watchdog_dev_exit(void) { unregister_chrdev_region(watchdog_devt, MAX_DOGS); class_unregister(&watchdog_class); + destroy_workqueue(watchdog_wq); } diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index 0b565f2ad242..8e82daecb7d3 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -10,8 +10,9 @@ #include -#include #include +#include +#include #include #include @@ -61,14 +62,19 @@ struct watchdog_ops { * @bootstatus: Status of the watchdog device at boot. * @timeout: The watchdog devices timeout value (in seconds). * @min_timeout:The watchdog devices minimum timeout value (in seconds). - * @max_timeout:The watchdog devices maximum timeout value (in seconds). + * @max_timeout:The watchdog devices maximum timeout value (in seconds) + * as configurable from user space. Only relevant if + * max_hw_heartbeat_ms is not provided. + * @max_hw_heartbeat_ms: + * Hardware limit for maximum timeout, in milli-seconds. + * Replaces max_timeout if specified. * @reboot_nb: The notifier block to stop watchdog on reboot. * @restart_nb: The notifier block to register a restart function. * @driver_data:Pointer to the drivers private data. * @wd_data: Pointer to watchdog core internal data. * @status: Field that contains the devices internal status bits. - * @deferred: entry in wtd_deferred_reg_list which is used to - * register early initialized watchdogs. + * @deferred: Entry in wtd_deferred_reg_list which is used to + * register early initialized watchdogs. * * The watchdog_device structure contains all information about a * watchdog timer device. @@ -89,6 +95,7 @@ struct watchdog_device { unsigned int timeout; unsigned int min_timeout; unsigned int max_timeout; + unsigned int max_hw_heartbeat_ms; struct notifier_block reboot_nb; struct notifier_block restart_nb; void *driver_data; @@ -128,13 +135,18 @@ static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigne { /* * The timeout is invalid if + * - the requested value is larger than UINT_MAX / 1000 + * (since internal calculations are done in milli-seconds), + * or * - the requested value is smaller than the configured minimum timeout, * or - * - a maximum timeout is configured, and the requested value is larger - * than the maximum timeout. + * - a maximum hardware timeout is not configured, a maximum timeout + * is configured, and the requested value is larger than the + * configured maximum timeout. */ - return t < wdd->min_timeout || - (wdd->max_timeout && t > wdd->max_timeout); + return t > UINT_MAX / 1000 || t < wdd->min_timeout || + (!wdd->max_hw_heartbeat_ms && wdd->max_timeout && + t > wdd->max_timeout); } /* Use the following functions to manipulate watchdog driver specific data */ -- cgit v1.2.3-58-ga151 From ee142889e32f564f9b5e57b68b06693ec5473074 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Sun, 28 Feb 2016 13:12:16 -0800 Subject: watchdog: Introduce WDOG_HW_RUNNING flag The WDOG_HW_RUNNING flag is expected to be set by watchdog drivers if the hardware watchdog is running. If the flag is set, the watchdog subsystem will ping the watchdog even if the watchdog device is closed. The watchdog driver stop function is now optional and may be omitted if the watchdog can not be stopped. If stopping the watchdog is not possible but the driver implements a stop function, it is responsible to set the WDOG_HW_RUNNING flag in its stop function. Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- Documentation/watchdog/watchdog-kernel-api.txt | 22 +++++++---- drivers/watchdog/watchdog_dev.c | 52 +++++++++++++++++++------- include/linux/watchdog.h | 10 +++++ 3 files changed, 64 insertions(+), 20 deletions(-) (limited to 'Documentation/watchdog') diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt index 15a02595ade1..954134a5c4a4 100644 --- a/Documentation/watchdog/watchdog-kernel-api.txt +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -137,10 +137,10 @@ are: * stop: with this routine the watchdog timer device is being stopped. The routine needs a pointer to the watchdog timer device structure as a parameter. It returns zero on success or a negative errno code for failure. - Some watchdog timer hardware can only be started and not be stopped. The - driver supporting this hardware needs to make sure that a start and stop - routine is being provided. This can be done by using a timer in the driver - that regularly sends a keepalive ping to the watchdog timer hardware. + Some watchdog timer hardware can only be started and not be stopped. + If a watchdog can not be stopped, the watchdog driver must set the + WDOG_HW_RUNNING flag in its stop function to inform the watchdog core that + the watchdog is still running. Not all watchdog timer hardware supports the same functionality. That's why all other routines/operations are optional. They only need to be provided if @@ -189,11 +189,19 @@ 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) + is active or not from user perspective. User space is expected to send + heartbeat requests to the driver while this flag is set. * 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_HW_RUNNING: Set by the watchdog driver if the hardware watchdog is + running. The bit must be set if the watchdog timer hardware can not be + stopped. The bit may also be set if the watchdog timer is running after + booting, before the watchdog device is opened. If set, the watchdog + infrastructure will send keepalives to the watchdog hardware while + WDOG_ACTIVE is not set. + Note: when you register the watchdog timer device with this bit set, + then opening /dev/watchdog will skip the start operation but send a keepalive + request instead. To set the WDOG_NO_WAY_OUT status bit (before registering your watchdog timer device) you can either: diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index e668a9e8b648..5d3a9fa4856e 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -92,7 +92,8 @@ static inline bool watchdog_need_worker(struct watchdog_device *wdd) * requests. * - Userspace requests a longer timeout than the hardware can handle. */ - return watchdog_active(wdd) && hm && t > hm; + return hm && ((watchdog_active(wdd) && t > hm) || + (t && !watchdog_active(wdd) && watchdog_hw_running(wdd))); } static long watchdog_next_keepalive(struct watchdog_device *wdd) @@ -108,6 +109,9 @@ static long watchdog_next_keepalive(struct watchdog_device *wdd) hw_heartbeat_ms = min(timeout_ms, wdd->max_hw_heartbeat_ms); keepalive_interval = msecs_to_jiffies(hw_heartbeat_ms / 2); + if (!watchdog_active(wdd)) + return keepalive_interval; + /* * To ensure that the watchdog times out wdd->timeout seconds * after the most recent ping from userspace, the last @@ -161,7 +165,7 @@ static int watchdog_ping(struct watchdog_device *wdd) { struct watchdog_core_data *wd_data = wdd->wd_data; - if (!watchdog_active(wdd)) + if (!watchdog_active(wdd) && !watchdog_hw_running(wdd)) return 0; wd_data->last_keepalive = jiffies; @@ -178,7 +182,7 @@ static void watchdog_ping_work(struct work_struct *work) mutex_lock(&wd_data->lock); wdd = wd_data->wdd; - if (wdd && watchdog_active(wdd)) + if (wdd && (watchdog_active(wdd) || watchdog_hw_running(wdd))) __watchdog_ping(wdd); mutex_unlock(&wd_data->lock); } @@ -204,7 +208,10 @@ static int watchdog_start(struct watchdog_device *wdd) return 0; started_at = jiffies; - err = wdd->ops->start(wdd); + if (watchdog_hw_running(wdd) && wdd->ops->ping) + err = wdd->ops->ping(wdd); + else + err = wdd->ops->start(wdd); if (err == 0) { set_bit(WDOG_ACTIVE, &wdd->status); wd_data->last_keepalive = started_at; @@ -228,8 +235,7 @@ static int watchdog_start(struct watchdog_device *wdd) static int watchdog_stop(struct watchdog_device *wdd) { - struct watchdog_core_data *wd_data = wdd->wd_data; - int err; + int err = 0; if (!watchdog_active(wdd)) return 0; @@ -243,7 +249,7 @@ static int watchdog_stop(struct watchdog_device *wdd) err = wdd->ops->stop(wdd); if (err == 0) { clear_bit(WDOG_ACTIVE, &wdd->status); - cancel_delayed_work(&wd_data->work); + watchdog_update_worker(wdd); } return err; @@ -641,7 +647,7 @@ static int watchdog_open(struct inode *inode, struct file *file) * If the /dev/watchdog device is open, we don't want the module * to be unloaded. */ - if (!try_module_get(wdd->ops->owner)) { + if (!watchdog_hw_running(wdd) && !try_module_get(wdd->ops->owner)) { err = -EBUSY; goto out_clear; } @@ -652,7 +658,8 @@ static int watchdog_open(struct inode *inode, struct file *file) file->private_data = wd_data; - kref_get(&wd_data->kref); + if (!watchdog_hw_running(wdd)) + kref_get(&wd_data->kref); /* dev/watchdog is a virtual (and thus non-seekable) filesystem */ return nonseekable_open(inode, file); @@ -713,15 +720,22 @@ static int watchdog_release(struct inode *inode, struct file *file) } cancel_delayed_work_sync(&wd_data->work); + watchdog_update_worker(wdd); /* make sure that /dev/watchdog can be re-opened */ clear_bit(_WDOG_DEV_OPEN, &wd_data->status); done: mutex_unlock(&wd_data->lock); - /* Allow the owner module to be unloaded again */ - module_put(wd_data->cdev.owner); - kref_put(&wd_data->kref, watchdog_core_data_release); + /* + * Allow the owner module to be unloaded again unless the watchdog + * is still running. If the watchdog is still running, it can not + * be stopped, and its driver must not be unloaded. + */ + if (!watchdog_hw_running(wdd)) { + module_put(wdd->ops->owner); + kref_put(&wd_data->kref, watchdog_core_data_release); + } return 0; } @@ -798,8 +812,20 @@ static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno) old_wd_data = NULL; kref_put(&wd_data->kref, watchdog_core_data_release); } + return err; } - return err; + + /* + * If the watchdog is running, prevent its driver from being unloaded, + * and schedule an immediate ping. + */ + if (watchdog_hw_running(wdd)) { + __module_get(wdd->ops->owner); + kref_get(&wd_data->kref); + queue_delayed_work(watchdog_wq, &wd_data->work, 0); + } + + return 0; } /* diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index 8e82daecb7d3..e2f45549b243 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -105,6 +105,7 @@ struct watchdog_device { #define WDOG_ACTIVE 0 /* Is the watchdog running/active */ #define WDOG_NO_WAY_OUT 1 /* Is 'nowayout' feature set ? */ #define WDOG_STOP_ON_REBOOT 2 /* Should be stopped on reboot */ +#define WDOG_HW_RUNNING 3 /* True if HW watchdog running */ struct list_head deferred; }; @@ -117,6 +118,15 @@ static inline bool watchdog_active(struct watchdog_device *wdd) return test_bit(WDOG_ACTIVE, &wdd->status); } +/* + * Use the following function to check whether or not the hardware watchdog + * is running + */ +static inline bool watchdog_hw_running(struct watchdog_device *wdd) +{ + return test_bit(WDOG_HW_RUNNING, &wdd->status); +} + /* Use the following function to set the nowayout feature */ static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout) { -- cgit v1.2.3-58-ga151 From d0684c8a9354953efdea214b437445c00743cf49 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Sun, 28 Feb 2016 13:12:17 -0800 Subject: watchdog: Make stop function optional Not all hardware watchdogs can be stopped. The driver for such watchdogs would typically only set the WATCHDOG_HW_RUNNING flag in its stop function. Make the stop function optional and set WATCHDOG_HW_RUNNING in the watchdog core if it is not provided. Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- Documentation/watchdog/watchdog-kernel-api.txt | 20 ++++++++++++-------- drivers/watchdog/watchdog_core.c | 2 +- drivers/watchdog/watchdog_dev.c | 6 +++++- 3 files changed, 18 insertions(+), 10 deletions(-) (limited to 'Documentation/watchdog') diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt index 954134a5c4a4..9eabca1d9355 100644 --- a/Documentation/watchdog/watchdog-kernel-api.txt +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -85,7 +85,8 @@ It contains following fields: If set, the infrastructure will send heartbeats to the watchdog driver if 'timeout' is larger than max_hw_heartbeat_ms, unless WDOG_ACTIVE is set and userspace failed to send a heartbeat for at least 'timeout' - seconds. + seconds. max_hw_heartbeat_ms must be set if a driver does not implement + the stop function. * 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. @@ -134,17 +135,20 @@ are: device. The routine needs a pointer to the watchdog timer device structure as a parameter. It returns zero on success or a negative errno code for failure. -* stop: with this routine the watchdog timer device is being stopped. - The routine needs a pointer to the watchdog timer device structure as a - parameter. It returns zero on success or a negative errno code for failure. - Some watchdog timer hardware can only be started and not be stopped. - If a watchdog can not be stopped, the watchdog driver must set the - WDOG_HW_RUNNING flag in its stop function to inform the watchdog core that - the watchdog is still running. Not all watchdog timer hardware supports the same functionality. That's why all other routines/operations are optional. They only need to be provided if they are supported. These optional routines/operations are: +* stop: with this routine the watchdog timer device is being stopped. + The routine needs a pointer to the watchdog timer device structure as a + parameter. It returns zero on success or a negative errno code for failure. + Some watchdog timer hardware can only be started and not be stopped. A + driver supporting such hardware does not have to implement the stop routine. + If a driver has no stop function, the watchdog core will set WDOG_HW_RUNNING + and start calling the driver's keepalive pings function after the watchdog + device is closed. + If a watchdog driver does not implement the stop function, it must set + max_hw_heartbeat_ms. * ping: this is the routine that sends a keepalive ping to the watchdog timer hardware. The routine needs a pointer to the watchdog timer device structure as a diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c index d9b3c9c023c4..c1658fe73d58 100644 --- a/drivers/watchdog/watchdog_core.c +++ b/drivers/watchdog/watchdog_core.c @@ -199,7 +199,7 @@ static int __watchdog_register_device(struct watchdog_device *wdd) return -EINVAL; /* Mandatory operations need to be supported */ - if (wdd->ops->start == NULL || wdd->ops->stop == NULL) + if (!wdd->ops->start || (!wdd->ops->stop && !wdd->max_hw_heartbeat_ms)) return -EINVAL; watchdog_check_min_max_timeout(wdd); diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 5d3a9fa4856e..5163c3eb3428 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -246,7 +246,11 @@ static int watchdog_stop(struct watchdog_device *wdd) return -EBUSY; } - err = wdd->ops->stop(wdd); + if (wdd->ops->stop) + err = wdd->ops->stop(wdd); + else + set_bit(WDOG_HW_RUNNING, &wdd->status); + if (err == 0) { clear_bit(WDOG_ACTIVE, &wdd->status); watchdog_update_worker(wdd); -- cgit v1.2.3-58-ga151 From 15013ad813f6544be8e79afc23672745950d59bc Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Sun, 28 Feb 2016 13:12:18 -0800 Subject: watchdog: Add support for minimum time between heartbeats Some watchdogs require a minimum time between heartbeats. Examples are the watchdogs in DA9062 and AT91SAM9x. Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- Documentation/watchdog/watchdog-kernel-api.txt | 3 +++ drivers/watchdog/watchdog_dev.c | 15 +++++++++++++++ include/linux/watchdog.h | 3 +++ 3 files changed, 21 insertions(+) (limited to 'Documentation/watchdog') diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt index 9eabca1d9355..917eeeabfa5e 100644 --- a/Documentation/watchdog/watchdog-kernel-api.txt +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -52,6 +52,7 @@ struct watchdog_device { unsigned int timeout; unsigned int min_timeout; unsigned int max_timeout; + unsigned int min_hw_heartbeat_ms; unsigned int max_hw_heartbeat_ms; struct notifier_block reboot_nb; struct notifier_block restart_nb; @@ -81,6 +82,8 @@ It contains following fields: * max_timeout: the watchdog timer's maximum timeout value (in seconds), as seen from userspace. If set, the maximum configurable value for 'timeout'. Not used if max_hw_heartbeat_ms is non-zero. +* min_hw_heartbeat_ms: Minimum time between heartbeats sent to the chip, + in milli-seconds. * max_hw_heartbeat_ms: Maximum hardware heartbeat, in milli-seconds. If set, the infrastructure will send heartbeats to the watchdog driver if 'timeout' is larger than max_hw_heartbeat_ms, unless WDOG_ACTIVE diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 5163c3eb3428..2d6110278eac 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -64,6 +64,7 @@ struct watchdog_core_data { struct watchdog_device *wdd; struct mutex lock; unsigned long last_keepalive; + unsigned long last_hw_keepalive; struct delayed_work work; unsigned long status; /* Internal status bits */ #define _WDOG_DEV_OPEN 0 /* Opened ? */ @@ -137,8 +138,19 @@ static inline void watchdog_update_worker(struct watchdog_device *wdd) static int __watchdog_ping(struct watchdog_device *wdd) { + struct watchdog_core_data *wd_data = wdd->wd_data; + unsigned long earliest_keepalive = wd_data->last_hw_keepalive + + msecs_to_jiffies(wdd->min_hw_heartbeat_ms); int err; + if (time_is_after_jiffies(earliest_keepalive)) { + mod_delayed_work(watchdog_wq, &wd_data->work, + earliest_keepalive - jiffies); + return 0; + } + + wd_data->last_hw_keepalive = jiffies; + if (wdd->ops->ping) err = wdd->ops->ping(wdd); /* ping the watchdog */ else @@ -819,6 +831,9 @@ static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno) return err; } + /* Record time of most recent heartbeat as 'just before now'. */ + wd_data->last_hw_keepalive = jiffies - 1; + /* * If the watchdog is running, prevent its driver from being unloaded, * and schedule an immediate ping. diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index e2f45549b243..51732d6c9555 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -65,6 +65,8 @@ struct watchdog_ops { * @max_timeout:The watchdog devices maximum timeout value (in seconds) * as configurable from user space. Only relevant if * max_hw_heartbeat_ms is not provided. + * @min_hw_heartbeat_ms: + * Minimum time between heartbeats, in milli-seconds. * @max_hw_heartbeat_ms: * Hardware limit for maximum timeout, in milli-seconds. * Replaces max_timeout if specified. @@ -95,6 +97,7 @@ struct watchdog_device { unsigned int timeout; unsigned int min_timeout; unsigned int max_timeout; + unsigned int min_hw_heartbeat_ms; unsigned int max_hw_heartbeat_ms; struct notifier_block reboot_nb; struct notifier_block restart_nb; -- cgit v1.2.3-58-ga151