diff options
Diffstat (limited to 'kernel/Documentation/watchdog')
| -rw-r--r-- | kernel/Documentation/watchdog/Makefile | 1 | ||||
| -rw-r--r-- | kernel/Documentation/watchdog/convert_drivers_to_kernel_api.txt | 218 | ||||
| -rw-r--r-- | kernel/Documentation/watchdog/hpwdt.txt | 95 | ||||
| -rw-r--r-- | kernel/Documentation/watchdog/pcwd-watchdog.txt | 66 | ||||
| -rw-r--r-- | kernel/Documentation/watchdog/src/.gitignore | 2 | ||||
| -rw-r--r-- | kernel/Documentation/watchdog/src/Makefile | 5 | ||||
| -rw-r--r-- | kernel/Documentation/watchdog/src/watchdog-simple.c | 24 | ||||
| -rw-r--r-- | kernel/Documentation/watchdog/src/watchdog-test.c | 86 | ||||
| -rw-r--r-- | kernel/Documentation/watchdog/watchdog-api.txt | 237 | ||||
| -rw-r--r-- | kernel/Documentation/watchdog/watchdog-kernel-api.txt | 226 | ||||
| -rw-r--r-- | kernel/Documentation/watchdog/watchdog-parameters.txt | 399 | ||||
| -rw-r--r-- | kernel/Documentation/watchdog/wdt.txt | 50 |
12 files changed, 1409 insertions, 0 deletions
diff --git a/kernel/Documentation/watchdog/Makefile b/kernel/Documentation/watchdog/Makefile new file mode 100644 index 000000000..6018f45f2 --- /dev/null +++ b/kernel/Documentation/watchdog/Makefile @@ -0,0 +1 @@ +subdir-y := src diff --git a/kernel/Documentation/watchdog/convert_drivers_to_kernel_api.txt b/kernel/Documentation/watchdog/convert_drivers_to_kernel_api.txt new file mode 100644 index 000000000..271b8850d --- /dev/null +++ b/kernel/Documentation/watchdog/convert_drivers_to_kernel_api.txt @@ -0,0 +1,218 @@ +Converting old watchdog drivers to the watchdog framework +by Wolfram Sang <w.sang@pengutronix.de> +========================================================= + +Before the watchdog framework came into the kernel, every driver had to +implement the API on its own. Now, as the framework factored out the common +components, those drivers can be lightened making it a user of the framework. +This document shall guide you for this task. The necessary steps are described +as well as things to look out for. + + +Remove the file_operations struct +--------------------------------- + +Old drivers define their own file_operations for actions like open(), write(), +etc... These are now handled by the framework and just call the driver when +needed. So, in general, the 'file_operations' struct and assorted functions can +go. Only very few driver-specific details have to be moved to other functions. +Here is a overview of the functions and probably needed actions: + +- open: Everything dealing with resource management (file-open checks, magic + close preparations) can simply go. Device specific stuff needs to go to the + driver specific start-function. Note that for some drivers, the start-function + also serves as the ping-function. If that is the case and you need start/stop + to be balanced (clocks!), you are better off refactoring a separate start-function. + +- close: Same hints as for open apply. + +- write: Can simply go, all defined behaviour is taken care of by the framework, + i.e. ping on write and magic char ('V') handling. + +- ioctl: While the driver is allowed to have extensions to the IOCTL interface, + the most common ones are handled by the framework, supported by some assistance + from the driver: + + WDIOC_GETSUPPORT: + Returns the mandatory watchdog_info struct from the driver + + WDIOC_GETSTATUS: + Needs the status-callback defined, otherwise returns 0 + + WDIOC_GETBOOTSTATUS: + Needs the bootstatus member properly set. Make sure it is 0 if you + don't have further support! + + WDIOC_SETOPTIONS: + No preparations needed + + WDIOC_KEEPALIVE: + If wanted, options in watchdog_info need to have WDIOF_KEEPALIVEPING + set + + WDIOC_SETTIMEOUT: + Options in watchdog_info need to have WDIOF_SETTIMEOUT set + and a set_timeout-callback has to be defined. The core will also + do limit-checking, if min_timeout and max_timeout in the watchdog + device are set. All is optional. + + WDIOC_GETTIMEOUT: + No preparations needed + + WDIOC_GETTIMELEFT: + It needs get_timeleft() callback to be defined. Otherwise it + will return EOPNOTSUPP + + Other IOCTLs can be served using the ioctl-callback. Note that this is mainly + intended for porting old drivers; new drivers should not invent private IOCTLs. + Private IOCTLs are processed first. When the callback returns with + -ENOIOCTLCMD, the IOCTLs of the framework will be tried, too. Any other error + is directly given to the user. + +Example conversion: + +-static const struct file_operations s3c2410wdt_fops = { +- .owner = THIS_MODULE, +- .llseek = no_llseek, +- .write = s3c2410wdt_write, +- .unlocked_ioctl = s3c2410wdt_ioctl, +- .open = s3c2410wdt_open, +- .release = s3c2410wdt_release, +-}; + +Check the functions for device-specific stuff and keep it for later +refactoring. The rest can go. + + +Remove the miscdevice +--------------------- + +Since the file_operations are gone now, you can also remove the 'struct +miscdevice'. The framework will create it on watchdog_dev_register() called by +watchdog_register_device(). + +-static struct miscdevice s3c2410wdt_miscdev = { +- .minor = WATCHDOG_MINOR, +- .name = "watchdog", +- .fops = &s3c2410wdt_fops, +-}; + + +Remove obsolete includes and defines +------------------------------------ + +Because of the simplifications, a few defines are probably unused now. Remove +them. Includes can be removed, too. For example: + +- #include <linux/fs.h> +- #include <linux/miscdevice.h> (if MODULE_ALIAS_MISCDEV is not used) +- #include <linux/uaccess.h> (if no custom IOCTLs are used) + + +Add the watchdog operations +--------------------------- + +All possible callbacks are defined in 'struct watchdog_ops'. You can find it +explained in 'watchdog-kernel-api.txt' in this directory. start(), stop() and +owner must be set, the rest are optional. You will easily find corresponding +functions in the old driver. Note that you will now get a pointer to the +watchdog_device as a parameter to these functions, so you probably have to +change the function header. Other changes are most likely not needed, because +here simply happens the direct hardware access. If you have device-specific +code left from the above steps, it should be refactored into these callbacks. + +Here is a simple example: + ++static struct watchdog_ops s3c2410wdt_ops = { ++ .owner = THIS_MODULE, ++ .start = s3c2410wdt_start, ++ .stop = s3c2410wdt_stop, ++ .ping = s3c2410wdt_keepalive, ++ .set_timeout = s3c2410wdt_set_heartbeat, ++}; + +A typical function-header change looks like: + +-static void s3c2410wdt_keepalive(void) ++static int s3c2410wdt_keepalive(struct watchdog_device *wdd) + { +... ++ ++ return 0; + } + +... + +- s3c2410wdt_keepalive(); ++ s3c2410wdt_keepalive(&s3c2410_wdd); + + +Add the watchdog device +----------------------- + +Now we need to create a 'struct watchdog_device' and populate it with the +necessary information for the framework. The struct is also explained in detail +in 'watchdog-kernel-api.txt' in this directory. We pass it the mandatory +watchdog_info struct and the newly created watchdog_ops. Often, old drivers +have their own record-keeping for things like bootstatus and timeout using +static variables. Those have to be converted to use the members in +watchdog_device. Note that the timeout values are unsigned int. Some drivers +use signed int, so this has to be converted, too. + +Here is a simple example for a watchdog device: + ++static struct watchdog_device s3c2410_wdd = { ++ .info = &s3c2410_wdt_ident, ++ .ops = &s3c2410wdt_ops, ++}; + + +Handle the 'nowayout' feature +----------------------------- + +A few drivers use nowayout statically, i.e. there is no module parameter for it +and only CONFIG_WATCHDOG_NOWAYOUT determines if the feature is going to be +used. This needs to be converted by initializing the status variable of the +watchdog_device like this: + + .status = WATCHDOG_NOWAYOUT_INIT_STATUS, + +Most drivers, however, also allow runtime configuration of nowayout, usually +by adding a module parameter. The conversion for this would be something like: + + watchdog_set_nowayout(&s3c2410_wdd, nowayout); + +The module parameter itself needs to stay, everything else related to nowayout +can go, though. This will likely be some code in open(), close() or write(). + + +Register the watchdog device +---------------------------- + +Replace misc_register(&miscdev) with watchdog_register_device(&watchdog_dev). +Make sure the return value gets checked and the error message, if present, +still fits. Also convert the unregister case. + +- ret = misc_register(&s3c2410wdt_miscdev); ++ ret = watchdog_register_device(&s3c2410_wdd); + +... + +- misc_deregister(&s3c2410wdt_miscdev); ++ watchdog_unregister_device(&s3c2410_wdd); + + +Update the Kconfig-entry +------------------------ + +The entry for the driver now needs to select WATCHDOG_CORE: + ++ select WATCHDOG_CORE + + +Create a patch and send it to upstream +-------------------------------------- + +Make sure you understood Documentation/SubmittingPatches and send your patch to +linux-watchdog@vger.kernel.org. We are looking forward to it :) + diff --git a/kernel/Documentation/watchdog/hpwdt.txt b/kernel/Documentation/watchdog/hpwdt.txt new file mode 100644 index 000000000..948807890 --- /dev/null +++ b/kernel/Documentation/watchdog/hpwdt.txt @@ -0,0 +1,95 @@ +Last reviewed: 06/02/2009 + + HP iLO2 NMI Watchdog Driver + NMI sourcing for iLO2 based ProLiant Servers + Documentation and Driver by + Thomas Mingarelli <thomas.mingarelli@hp.com> + + The HP iLO2 NMI Watchdog driver is a kernel module that provides basic + watchdog functionality and the added benefit of NMI sourcing. Both the + watchdog functionality and the NMI sourcing capability need to be enabled + by the user. Remember that the two modes are not dependent on one another. + A user can have the NMI sourcing without the watchdog timer and vice-versa. + + Watchdog functionality is enabled like any other common watchdog driver. That + is, an application needs to be started that kicks off the watchdog timer. A + basic application exists in the Documentation/watchdog/src directory called + watchdog-test.c. Simply compile the C file and kick it off. If the system + gets into a bad state and hangs, the HP ProLiant iLO 2 timer register will + not be updated in a timely fashion and a hardware system reset (also known as + an Automatic Server Recovery (ASR)) event will occur. + + The hpwdt driver also has four (4) module parameters. They are the following: + + soft_margin - allows the user to set the watchdog timer value + allow_kdump - allows the user to save off a kernel dump image after an NMI + nowayout - basic watchdog parameter that does not allow the timer to + be restarted or an impending ASR to be escaped. + priority - determines whether or not the hpwdt driver is first on the + die_notify list to handle NMIs or last. The default value + for this module parameter is 0 or LAST. If the user wants to + enable NMI sourcing then reload the hpwdt driver with + priority=1 (and boot with nmi_watchdog=0). + + NOTE: More information about watchdog drivers in general, including the ioctl + interface to /dev/watchdog can be found in + Documentation/watchdog/watchdog-api.txt and Documentation/IPMI.txt. + + The priority parameter was introduced due to other kernel software that relied + on handling NMIs (like oprofile). Keeping hpwdt's priority at 0 (or LAST) + enables the users of NMIs for non critical events to be work as expected. + + The NMI sourcing capability is disabled by default due to the inability to + distinguish between "NMI Watchdog Ticks" and "HW generated NMI events" in the + Linux kernel. What this means is that the hpwdt nmi handler code is called + each time the NMI signal fires off. This could amount to several thousands of + NMIs in a matter of seconds. If a user sees the Linux kernel's "dazed and + confused" message in the logs or if the system gets into a hung state, then + the hpwdt driver can be reloaded with the "priority" module parameter set + (priority=1). + + 1. If the kernel has not been booted with nmi_watchdog turned off then + edit /boot/grub/menu.lst and place the nmi_watchdog=0 at the end of the + currently booting kernel line. + 2. reboot the sever + 3. Once the system comes up perform a rmmod hpwdt + 4. insmod /lib/modules/`uname -r`/kernel/drivers/char/watchdog/hpwdt.ko priority=1 + + Now, the hpwdt can successfully receive and source the NMI and provide a log + message that details the reason for the NMI (as determined by the HP BIOS). + + Below is a list of NMIs the HP BIOS understands along with the associated + code (reason): + + No source found 00h + + Uncorrectable Memory Error 01h + + ASR NMI 1Bh + + PCI Parity Error 20h + + NMI Button Press 27h + + SB_BUS_NMI 28h + + ILO Doorbell NMI 29h + + ILO IOP NMI 2Ah + + ILO Watchdog NMI 2Bh + + Proc Throt NMI 2Ch + + Front Side Bus NMI 2Dh + + PCI Express Error 2Fh + + DMA controller NMI 30h + + Hypertransport/CSI Error 31h + + + + -- Tom Mingarelli + (thomas.mingarelli@hp.com) diff --git a/kernel/Documentation/watchdog/pcwd-watchdog.txt b/kernel/Documentation/watchdog/pcwd-watchdog.txt new file mode 100644 index 000000000..4f6805239 --- /dev/null +++ b/kernel/Documentation/watchdog/pcwd-watchdog.txt @@ -0,0 +1,66 @@ +Last reviewed: 10/05/2007 + + Berkshire Products PC Watchdog Card + Support for ISA Cards Revision A and C + Documentation and Driver by Ken Hollis <kenji@bitgate.com> + + The PC Watchdog is a card that offers the same type of functionality that + the WDT card does, only it doesn't require an IRQ to run. Furthermore, + the Revision C card allows you to monitor any IO Port to automatically + trigger the card into being reset. This way you can make the card + monitor hard drive status, or anything else you need. + + The Watchdog Driver has one basic role: to talk to the card and send + signals to it so it doesn't reset your computer ... at least during + normal operation. + + The Watchdog Driver will automatically find your watchdog card, and will + attach a running driver for use with that card. After the watchdog + drivers have initialized, you can then talk to the card using a PC + Watchdog program. + + I suggest putting a "watchdog -d" before the beginning of an fsck, and + a "watchdog -e -t 1" immediately after the end of an fsck. (Remember + to run the program with an "&" to run it in the background!) + + If you want to write a program to be compatible with the PC Watchdog + driver, simply use of modify the watchdog test program: + Documentation/watchdog/src/watchdog-test.c + + + Other IOCTL functions include: + + WDIOC_GETSUPPORT + This returns the support of the card itself. This + returns in structure "PCWDS" which returns: + options = WDIOS_TEMPPANIC + (This card supports temperature) + firmware_version = xxxx + (Firmware version of the card) + + WDIOC_GETSTATUS + This returns the status of the card, with the bits of + WDIOF_* bitwise-anded into the value. (The comments + are in linux/pcwd.h) + + WDIOC_GETBOOTSTATUS + This returns the status of the card that was reported + at bootup. + + WDIOC_GETTEMP + This returns the temperature of the card. (You can also + read /dev/watchdog, which gives a temperature update + every second.) + + WDIOC_SETOPTIONS + This lets you set the options of the card. You can either + enable or disable the card this way. + + WDIOC_KEEPALIVE + This pings the card to tell it not to reset your computer. + + And that's all she wrote! + + -- Ken Hollis + (kenji@bitgate.com) + diff --git a/kernel/Documentation/watchdog/src/.gitignore b/kernel/Documentation/watchdog/src/.gitignore new file mode 100644 index 000000000..ac90997db --- /dev/null +++ b/kernel/Documentation/watchdog/src/.gitignore @@ -0,0 +1,2 @@ +watchdog-simple +watchdog-test diff --git a/kernel/Documentation/watchdog/src/Makefile b/kernel/Documentation/watchdog/src/Makefile new file mode 100644 index 000000000..4a892c304 --- /dev/null +++ b/kernel/Documentation/watchdog/src/Makefile @@ -0,0 +1,5 @@ +# List of programs to build +hostprogs-y := watchdog-simple watchdog-test + +# Tell kbuild to always build the programs +always := $(hostprogs-y) diff --git a/kernel/Documentation/watchdog/src/watchdog-simple.c b/kernel/Documentation/watchdog/src/watchdog-simple.c new file mode 100644 index 000000000..ba45803a2 --- /dev/null +++ b/kernel/Documentation/watchdog/src/watchdog-simple.c @@ -0,0 +1,24 @@ +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <fcntl.h> + +int main(void) +{ + int fd = open("/dev/watchdog", O_WRONLY); + int ret = 0; + if (fd == -1) { + perror("watchdog"); + exit(EXIT_FAILURE); + } + while (1) { + ret = write(fd, "\0", 1); + if (ret != 1) { + ret = -1; + break; + } + sleep(10); + } + close(fd); + return ret; +} diff --git a/kernel/Documentation/watchdog/src/watchdog-test.c b/kernel/Documentation/watchdog/src/watchdog-test.c new file mode 100644 index 000000000..3da822967 --- /dev/null +++ b/kernel/Documentation/watchdog/src/watchdog-test.c @@ -0,0 +1,86 @@ +/* + * Watchdog Driver Test Program + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <fcntl.h> +#include <signal.h> +#include <sys/ioctl.h> +#include <linux/types.h> +#include <linux/watchdog.h> + +int fd; + +/* + * This function simply sends an IOCTL to the driver, which in turn ticks + * the PC Watchdog card to reset its internal timer so it doesn't trigger + * a computer reset. + */ +static void keep_alive(void) +{ + int dummy; + + ioctl(fd, WDIOC_KEEPALIVE, &dummy); +} + +/* + * The main program. Run the program with "-d" to disable the card, + * or "-e" to enable the card. + */ + +static void term(int sig) +{ + close(fd); + fprintf(stderr, "Stopping watchdog ticks...\n"); + exit(0); +} + +int main(int argc, char *argv[]) +{ + int flags; + + fd = open("/dev/watchdog", O_WRONLY); + + if (fd == -1) { + fprintf(stderr, "Watchdog device not enabled.\n"); + fflush(stderr); + exit(-1); + } + + if (argc > 1) { + if (!strncasecmp(argv[1], "-d", 2)) { + flags = WDIOS_DISABLECARD; + ioctl(fd, WDIOC_SETOPTIONS, &flags); + fprintf(stderr, "Watchdog card disabled.\n"); + fflush(stderr); + goto end; + } else if (!strncasecmp(argv[1], "-e", 2)) { + flags = WDIOS_ENABLECARD; + ioctl(fd, WDIOC_SETOPTIONS, &flags); + fprintf(stderr, "Watchdog card enabled.\n"); + fflush(stderr); + goto end; + } else { + fprintf(stderr, "-d to disable, -e to enable.\n"); + fprintf(stderr, "run by itself to tick the card.\n"); + fflush(stderr); + goto end; + } + } else { + fprintf(stderr, "Watchdog Ticking Away!\n"); + fflush(stderr); + } + + signal(SIGINT, term); + + while(1) { + keep_alive(); + sleep(1); + } +end: + close(fd); + return 0; +} diff --git a/kernel/Documentation/watchdog/watchdog-api.txt b/kernel/Documentation/watchdog/watchdog-api.txt new file mode 100644 index 000000000..b3a701f48 --- /dev/null +++ b/kernel/Documentation/watchdog/watchdog-api.txt @@ -0,0 +1,237 @@ +Last reviewed: 10/05/2007 + + +The Linux Watchdog driver API. + +Copyright 2002 Christer Weingel <wingel@nano-system.com> + +Some parts of this document are copied verbatim from the sbc60xxwdt +driver which is (c) Copyright 2000 Jakob Oestergaard <jakob@ostenfeld.dk> + +This document describes the state of the Linux 2.4.18 kernel. + +Introduction: + +A Watchdog Timer (WDT) is a hardware circuit that can reset the +computer system in case of a software fault. You probably knew that +already. + +Usually a userspace daemon will notify the kernel watchdog driver via the +/dev/watchdog special device file that userspace is still alive, at +regular intervals. When such a notification occurs, the driver will +usually tell the hardware watchdog that everything is in order, and +that the watchdog should wait for yet another little while to reset +the system. If userspace fails (RAM error, kernel bug, whatever), the +notifications cease to occur, and the hardware watchdog will reset the +system (causing a reboot) after the timeout occurs. + +The Linux watchdog API is a rather ad-hoc construction and different +drivers implement different, and sometimes incompatible, parts of it. +This file is an attempt to document the existing usage and allow +future driver writers to use it as a reference. + +The simplest API: + +All drivers support the basic mode of operation, where the watchdog +activates as soon as /dev/watchdog is opened and will reboot unless +the watchdog is pinged within a certain time, this time is called the +timeout or margin. The simplest way to ping the watchdog is to write +some data to the device. So a very simple watchdog daemon would look +like this source file: see Documentation/watchdog/src/watchdog-simple.c + +A more advanced driver could for example check that a HTTP server is +still responding before doing the write call to ping the watchdog. + +When the device is closed, the watchdog is disabled, unless the "Magic +Close" feature is supported (see below). This is not always such a +good idea, since if there is a bug in the watchdog daemon and it +crashes the system will not reboot. Because of this, some of the +drivers support the configuration option "Disable watchdog shutdown on +close", CONFIG_WATCHDOG_NOWAYOUT. If it is set to Y when compiling +the kernel, there is no way of disabling the watchdog once it has been +started. So, if the watchdog daemon crashes, the system will reboot +after the timeout has passed. Watchdog devices also usually support +the nowayout module parameter so that this option can be controlled at +runtime. + +Magic Close feature: + +If a driver supports "Magic Close", the driver will not disable the +watchdog unless a specific magic character 'V' has been sent to +/dev/watchdog just before closing the file. If the userspace daemon +closes the file without sending this special character, the driver +will assume that the daemon (and userspace in general) died, and will +stop pinging the watchdog without disabling it first. This will then +cause a reboot if the watchdog is not re-opened in sufficient time. + +The ioctl API: + +All conforming drivers also support an ioctl API. + +Pinging the watchdog using an ioctl: + +All drivers that have an ioctl interface support at least one ioctl, +KEEPALIVE. This ioctl does exactly the same thing as a write to the +watchdog device, so the main loop in the above program could be +replaced with: + + while (1) { + ioctl(fd, WDIOC_KEEPALIVE, 0); + sleep(10); + } + +the argument to the ioctl is ignored. + +Setting and getting the timeout: + +For some drivers it is possible to modify the watchdog timeout on the +fly with the SETTIMEOUT ioctl, those drivers have the WDIOF_SETTIMEOUT +flag set in their option field. The argument is an integer +representing the timeout in seconds. The driver returns the real +timeout used in the same variable, and this timeout might differ from +the requested one due to limitation of the hardware. + + int timeout = 45; + ioctl(fd, WDIOC_SETTIMEOUT, &timeout); + printf("The timeout was set to %d seconds\n", timeout); + +This example might actually print "The timeout was set to 60 seconds" +if the device has a granularity of minutes for its timeout. + +Starting with the Linux 2.4.18 kernel, it is possible to query the +current timeout using the GETTIMEOUT ioctl. + + ioctl(fd, WDIOC_GETTIMEOUT, &timeout); + printf("The timeout was is %d seconds\n", timeout); + +Pretimeouts: + +Some watchdog timers can be set to have a trigger go off before the +actual time they will reset the system. This can be done with an NMI, +interrupt, or other mechanism. This allows Linux to record useful +information (like panic information and kernel coredumps) before it +resets. + + pretimeout = 10; + ioctl(fd, WDIOC_SETPRETIMEOUT, &pretimeout); + +Note that the pretimeout is the number of seconds before the time +when the timeout will go off. It is not the number of seconds until +the pretimeout. So, for instance, if you set the timeout to 60 seconds +and the pretimeout to 10 seconds, the pretimeout will go off in 50 +seconds. Setting a pretimeout to zero disables it. + +There is also a get function for getting the pretimeout: + + ioctl(fd, WDIOC_GETPRETIMEOUT, &timeout); + printf("The pretimeout was is %d seconds\n", timeout); + +Not all watchdog drivers will support a pretimeout. + +Get the number of seconds before reboot: + +Some watchdog drivers have the ability to report the remaining time +before the system will reboot. The WDIOC_GETTIMELEFT is the ioctl +that returns the number of seconds before reboot. + + ioctl(fd, WDIOC_GETTIMELEFT, &timeleft); + printf("The timeout was is %d seconds\n", timeleft); + +Environmental monitoring: + +All watchdog drivers are required return more information about the system, +some do temperature, fan and power level monitoring, some can tell you +the reason for the last reboot of the system. The GETSUPPORT ioctl is +available to ask what the device can do: + + struct watchdog_info ident; + ioctl(fd, WDIOC_GETSUPPORT, &ident); + +the fields returned in the ident struct are: + + identity a string identifying the watchdog driver + firmware_version the firmware version of the card if available + options a flags describing what the device supports + +the options field can have the following bits set, and describes what +kind of information that the GET_STATUS and GET_BOOT_STATUS ioctls can +return. [FIXME -- Is this correct?] + + WDIOF_OVERHEAT Reset due to CPU overheat + +The machine was last rebooted by the watchdog because the thermal limit was +exceeded + + WDIOF_FANFAULT Fan failed + +A system fan monitored by the watchdog card has failed + + WDIOF_EXTERN1 External relay 1 + +External monitoring relay/source 1 was triggered. Controllers intended for +real world applications include external monitoring pins that will trigger +a reset. + + WDIOF_EXTERN2 External relay 2 + +External monitoring relay/source 2 was triggered + + WDIOF_POWERUNDER Power bad/power fault + +The machine is showing an undervoltage status + + WDIOF_CARDRESET Card previously reset the CPU + +The last reboot was caused by the watchdog card + + WDIOF_POWEROVER Power over voltage + +The machine is showing an overvoltage status. Note that if one level is +under and one over both bits will be set - this may seem odd but makes +sense. + + WDIOF_KEEPALIVEPING Keep alive ping reply + +The watchdog saw a keepalive ping since it was last queried. + + WDIOF_SETTIMEOUT Can set/get the timeout + +The watchdog can do pretimeouts. + + WDIOF_PRETIMEOUT Pretimeout (in seconds), get/set + + +For those drivers that return any bits set in the option field, the +GETSTATUS and GETBOOTSTATUS ioctls can be used to ask for the current +status, and the status at the last reboot, respectively. + + int flags; + ioctl(fd, WDIOC_GETSTATUS, &flags); + + or + + ioctl(fd, WDIOC_GETBOOTSTATUS, &flags); + +Note that not all devices support these two calls, and some only +support the GETBOOTSTATUS call. + +Some drivers can measure the temperature using the GETTEMP ioctl. The +returned value is the temperature in degrees fahrenheit. + + int temperature; + ioctl(fd, WDIOC_GETTEMP, &temperature); + +Finally the SETOPTIONS ioctl can be used to control some aspects of +the cards operation. + + int options = 0; + ioctl(fd, WDIOC_SETOPTIONS, &options); + +The following options are available: + + WDIOS_DISABLECARD Turn off the watchdog timer + WDIOS_ENABLECARD Turn on the watchdog timer + WDIOS_TEMPPANIC Kernel panic on temperature trip + +[FIXME -- better explanations] + diff --git a/kernel/Documentation/watchdog/watchdog-kernel-api.txt b/kernel/Documentation/watchdog/watchdog-kernel-api.txt new file mode 100644 index 000000000..a0438f395 --- /dev/null +++ b/kernel/Documentation/watchdog/watchdog-kernel-api.txt @@ -0,0 +1,226 @@ +The Linux WatchDog Timer Driver Core kernel API. +=============================================== +Last reviewed: 12-Feb-2013 + +Wim Van Sebroeck <wim@iguana.be> + +Introduction +------------ +This document does not describe what a WatchDog Timer (WDT) Driver or Device is. +It also does not describe the API which can be used by user space to communicate +with a WatchDog Timer. If you want to know this then please read the following +file: Documentation/watchdog/watchdog-api.txt . + +So what does this document describe? It describes the API that can be used by +WatchDog Timer Drivers that want to use the WatchDog Timer Driver Core +Framework. This framework provides all interfacing towards user space so that +the same code does not have to be reproduced each time. This also means that +a watchdog timer driver then only needs to provide the different routines +(operations) that control the watchdog timer (WDT). + +The API +------- +Each watchdog timer driver that wants to use the WatchDog Timer Driver Core +must #include <linux/watchdog.h> (you would have to do this anyway when +writing a watchdog device driver). This include file contains following +register/unregister routines: + +extern int watchdog_register_device(struct watchdog_device *); +extern void watchdog_unregister_device(struct watchdog_device *); + +The watchdog_register_device routine registers a watchdog timer device. +The parameter of this routine is a pointer to a watchdog_device structure. +This routine returns zero on success and a negative errno code for failure. + +The watchdog_unregister_device routine deregisters a registered watchdog timer +device. The parameter of this routine is the pointer to the registered +watchdog_device structure. + +The watchdog device structure looks like this: + +struct watchdog_device { + int id; + struct cdev cdev; + struct device *dev; + struct device *parent; + const struct watchdog_info *info; + const struct watchdog_ops *ops; + unsigned int bootstatus; + unsigned int timeout; + unsigned int min_timeout; + unsigned int max_timeout; + void *driver_data; + struct mutex lock; + unsigned long status; +}; + +It contains following fields: +* id: set by watchdog_register_device, id 0 is special. It has both a + /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. +* 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). +* 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. +* 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, ...). + +The list of watchdog operations is defined as: + +struct watchdog_ops { + struct module *owner; + /* mandatory operations */ + int (*start)(struct watchdog_device *); + int (*stop)(struct watchdog_device *); + /* optional operations */ + int (*ping)(struct watchdog_device *); + 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 *); + long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long); +}; + +It is important that you first define the module owner of the watchdog timer +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 + 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. 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. + +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: +* 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 + parameter. It returns zero on success or a negative errno code for failure. + Most hardware that does not support this as a separate function uses the + start function to restart the watchdog timer hardware. And that's also what + the watchdog timer driver core does: to send a keepalive ping to the watchdog + timer hardware it will either use the ping operation (when available) or the + start operation (when the ping operation is not available). + (Note: the WDIOC_KEEPALIVE ioctl call will only be active when the + WDIOF_KEEPALIVEPING bit has been set in the option field on the watchdog's + info structure). +* status: this routine checks the status of the watchdog timer device. The + status of the device is reported with watchdog WDIOF_* status flags/bits. +* set_timeout: this routine checks and changes the timeout 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 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). + (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. +* 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 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: + * set it statically in your watchdog_device struct with + .status = WATCHDOG_NOWAYOUT_INIT_STATUS, + (this will set the value the same as CONFIG_WATCHDOG_NOWAYOUT) or + * use the following helper function: + static inline void watchdog_set_nowayout(struct watchdog_device *wdd, int nowayout) + +Note: The WatchDog Timer Driver Core supports the magic close feature and +the nowayout feature. To use the magic close feature you must set the +WDIOF_MAGICCLOSE bit in the options field of the watchdog's info structure. +The nowayout feature will overrule the magic close feature. + +To get or set driver specific data the following two helper functions should be +used: + +static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data) +static inline void *watchdog_get_drvdata(struct watchdog_device *wdd) + +The watchdog_set_drvdata function allows you to add driver specific data. The +arguments of this function are the watchdog device where you want to add the +driver specific data to and a pointer to the data itself. + +The watchdog_get_drvdata function allows you to retrieve driver specific data. +The argument of this function is the watchdog device where you want to retrieve +data from. The function returns the pointer to the driver specific data. + +To initialize the timeout field, the following function can be used: + +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. +This routine returns zero on success and a negative errno code for failure. diff --git a/kernel/Documentation/watchdog/watchdog-parameters.txt b/kernel/Documentation/watchdog/watchdog-parameters.txt new file mode 100644 index 000000000..692791cc6 --- /dev/null +++ b/kernel/Documentation/watchdog/watchdog-parameters.txt @@ -0,0 +1,399 @@ +This file provides information on the module parameters of many of +the Linux watchdog drivers. Watchdog driver parameter specs should +be listed here unless the driver has its own driver-specific information +file. + + +See Documentation/kernel-parameters.txt for information on +providing kernel parameters for builtin drivers versus loadable +modules. + + +------------------------------------------------- +acquirewdt: +wdt_stop: Acquire WDT 'stop' io port (default 0x43) +wdt_start: Acquire WDT 'start' io port (default 0x443) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +advantechwdt: +wdt_stop: Advantech WDT 'stop' io port (default 0x443) +wdt_start: Advantech WDT 'start' io port (default 0x443) +timeout: Watchdog timeout in seconds. 1<= timeout <=63, default=60. +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +alim1535_wdt: +timeout: Watchdog timeout in seconds. (0 < timeout < 18000, default=60 +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +alim7101_wdt: +timeout: Watchdog timeout in seconds. (1<=timeout<=3600, default=30 +use_gpio: Use the gpio watchdog (required by old cobalt boards). + default=0/off/no +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +ar7_wdt: +margin: Watchdog margin in seconds (default=60) +nowayout: Disable watchdog shutdown on close + (default=kernel config parameter) +------------------------------------------------- +at32ap700x_wdt: +timeout: Timeout value. Limited to be 1 or 2 seconds. (default=2) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +at91rm9200_wdt: +wdt_time: Watchdog time in seconds. (default=5) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +at91sam9_wdt: +heartbeat: Watchdog heartbeats in seconds. (default = 15) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +bcm47xx_wdt: +wdt_time: Watchdog time in seconds. (default=30) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +bfin_wdt: +timeout: Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default=20) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +coh901327_wdt: +margin: Watchdog margin in seconds (default 60s) +------------------------------------------------- +cpu5wdt: +port: base address of watchdog card, default is 0x91 +verbose: be verbose, default is 0 (no) +ticks: count down ticks, default is 10000 +------------------------------------------------- +cpwd: +wd0_timeout: Default watchdog0 timeout in 1/10secs +wd1_timeout: Default watchdog1 timeout in 1/10secs +wd2_timeout: Default watchdog2 timeout in 1/10secs +------------------------------------------------- +da9052wdt: +timeout: Watchdog timeout in seconds. 2<= timeout <=131, default=2.048s +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +davinci_wdt: +heartbeat: Watchdog heartbeat period in seconds from 1 to 600, default 60 +------------------------------------------------- +ep93xx_wdt: +nowayout: Watchdog cannot be stopped once started +timeout: Watchdog timeout in seconds. (1<=timeout<=3600, default=TBD) +------------------------------------------------- +eurotechwdt: +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +io: Eurotech WDT io port (default=0x3f0) +irq: Eurotech WDT irq (default=10) +ev: Eurotech WDT event type (default is `int') +------------------------------------------------- +gef_wdt: +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +geodewdt: +timeout: Watchdog timeout in seconds. 1<= timeout <=131, default=60. +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +i6300esb: +heartbeat: Watchdog heartbeat in seconds. (1<heartbeat<2046, default=30) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +iTCO_wdt: +heartbeat: Watchdog heartbeat in seconds. + (2<heartbeat<39 (TCO v1) or 613 (TCO v2), default=30) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +iTCO_vendor_support: +vendorsupport: iTCO vendor specific support mode, default=0 (none), + 1=SuperMicro Pent3, 2=SuperMicro Pent4+, 911=Broken SMI BIOS +------------------------------------------------- +ib700wdt: +timeout: Watchdog timeout in seconds. 0<= timeout <=30, default=30. +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +ibmasr: +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +imx2_wdt: +timeout: Watchdog timeout in seconds (default 60 s) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +indydog: +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +iop_wdt: +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +it8712f_wdt: +margin: Watchdog margin in seconds (default 60) +nowayout: Disable watchdog shutdown on close + (default=kernel config parameter) +------------------------------------------------- +it87_wdt: +nogameport: Forbid the activation of game port, default=0 +nocir: Forbid the use of CIR (workaround for some buggy setups); set to 1 if +system resets despite watchdog daemon running, default=0 +exclusive: Watchdog exclusive device open, default=1 +timeout: Watchdog timeout in seconds, default=60 +testmode: Watchdog test mode (1 = no reboot), default=0 +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +ixp2000_wdt: +heartbeat: Watchdog heartbeat in seconds (default 60s) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +ixp4xx_wdt: +heartbeat: Watchdog heartbeat in seconds (default 60s) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +ks8695_wdt: +wdt_time: Watchdog time in seconds. (default=5) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +machzwd: +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +action: after watchdog resets, generate: + 0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI +------------------------------------------------- +max63xx_wdt: +heartbeat: Watchdog heartbeat period in seconds from 1 to 60, default 60 +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +nodelay: Force selection of a timeout setting without initial delay + (max6373/74 only, default=0) +------------------------------------------------- +mixcomwd: +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +mpc8xxx_wdt: +timeout: Watchdog timeout in ticks. (0<timeout<65536, default=65535) +reset: Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +mv64x60_wdt: +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +nuc900_wdt: +heartbeat: Watchdog heartbeats in seconds. + (default = 15) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +omap_wdt: +timer_margin: initial watchdog timeout (in seconds) +------------------------------------------------- +orion_wdt: +heartbeat: Initial watchdog heartbeat in seconds +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +pc87413_wdt: +io: pc87413 WDT I/O port (default: io). +timeout: Watchdog timeout in minutes (default=timeout). +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +pika_wdt: +heartbeat: Watchdog heartbeats in seconds. (default = 15) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +pnx4008_wdt: +heartbeat: Watchdog heartbeat period in seconds from 1 to 60, default 19 +nowayout: Set to 1 to keep watchdog running after device release +------------------------------------------------- +pnx833x_wdt: +timeout: Watchdog timeout in Mhz. (68Mhz clock), default=2040000000 (30 seconds) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +start_enabled: Watchdog is started on module insertion (default=1) +------------------------------------------------- +rc32434_wdt: +timeout: Watchdog timeout value, in seconds (default=20) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +riowd: +riowd_timeout: Watchdog timeout in minutes (default=1) +------------------------------------------------- +s3c2410_wdt: +tmr_margin: Watchdog tmr_margin in seconds. (default=15) +tmr_atboot: Watchdog is started at boot time if set to 1, default=0 +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +soft_noboot: Watchdog action, set to 1 to ignore reboots, 0 to reboot +debug: Watchdog debug, set to >1 for debug, (default 0) +------------------------------------------------- +sa1100_wdt: +margin: Watchdog margin in seconds (default 60s) +------------------------------------------------- +sb_wdog: +timeout: Watchdog timeout in microseconds (max/default 8388607 or 8.3ish secs) +------------------------------------------------- +sbc60xxwdt: +wdt_stop: SBC60xx WDT 'stop' io port (default 0x45) +wdt_start: SBC60xx WDT 'start' io port (default 0x443) +timeout: Watchdog timeout in seconds. (1<=timeout<=3600, default=30) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +sbc7240_wdt: +timeout: Watchdog timeout in seconds. (1<=timeout<=255, default=30) +nowayout: Disable watchdog when closing device file +------------------------------------------------- +sbc8360: +timeout: Index into timeout table (0-63) (default=27 (60s)) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +sbc_epx_c3: +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +sbc_fitpc2_wdt: +margin: Watchdog margin in seconds (default 60s) +nowayout: Watchdog cannot be stopped once started +------------------------------------------------- +sc1200wdt: +isapnp: When set to 0 driver ISA PnP support will be disabled (default=1) +io: io port +timeout: range is 0-255 minutes, default is 1 +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +sc520_wdt: +timeout: Watchdog timeout in seconds. (1 <= timeout <= 3600, default=30) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +sch311x_wdt: +force_id: Override the detected device ID +therm_trip: Should a ThermTrip trigger the reset generator +timeout: Watchdog timeout in seconds. 1<= timeout <=15300, default=60 +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +scx200_wdt: +margin: Watchdog margin in seconds +nowayout: Disable watchdog shutdown on close +------------------------------------------------- +shwdt: +clock_division_ratio: Clock division ratio. Valid ranges are from 0x5 (1.31ms) + to 0x7 (5.25ms). (default=7) +heartbeat: Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default=30 +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +smsc37b787_wdt: +timeout: range is 1-255 units, default is 60 +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +softdog: +soft_margin: Watchdog soft_margin in seconds. + (0 < soft_margin < 65536, default=60) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +soft_noboot: Softdog action, set to 1 to ignore reboots, 0 to reboot + (default=0) +------------------------------------------------- +stmp3xxx_wdt: +heartbeat: Watchdog heartbeat period in seconds from 1 to 4194304, default 19 +------------------------------------------------- +tegra_wdt: +heartbeat: Watchdog heartbeats in seconds. (default = 120) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +ts72xx_wdt: +timeout: Watchdog timeout in seconds. (1 <= timeout <= 8, default=8) +nowayout: Disable watchdog shutdown on close +------------------------------------------------- +twl4030_wdt: +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +txx9wdt: +timeout: Watchdog timeout in seconds. (0<timeout<N, default=60) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +w83627hf_wdt: +wdt_io: w83627hf/thf WDT io port (default 0x2E) +timeout: Watchdog timeout in seconds. 1 <= timeout <= 255, default=60. +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +w83697hf_wdt: +wdt_io: w83697hf/hg WDT io port (default 0x2e, 0 = autodetect) +timeout: Watchdog timeout in seconds. 1<= timeout <=255 (default=60) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +early_disable: Watchdog gets disabled at boot time (default=1) +------------------------------------------------- +w83697ug_wdt: +wdt_io: w83697ug/uf WDT io port (default 0x2e) +timeout: Watchdog timeout in seconds. 1<= timeout <=255 (default=60) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +w83877f_wdt: +timeout: Watchdog timeout in seconds. (1<=timeout<=3600, default=30) +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +w83977f_wdt: +timeout: Watchdog timeout in seconds (15..7635), default=45) +testmode: Watchdog testmode (1 = no reboot), default=0 +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +wafer5823wdt: +timeout: Watchdog timeout in seconds. 1 <= timeout <= 255, default=60. +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +wdt285: +soft_margin: Watchdog timeout in seconds (default=60) +------------------------------------------------- +wdt977: +timeout: Watchdog timeout in seconds (60..15300, default=60) +testmode: Watchdog testmode (1 = no reboot), default=0 +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +wm831x_wdt: +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- +wm8350_wdt: +nowayout: Watchdog cannot be stopped once started + (default=kernel config parameter) +------------------------------------------------- diff --git a/kernel/Documentation/watchdog/wdt.txt b/kernel/Documentation/watchdog/wdt.txt new file mode 100644 index 000000000..061c2e353 --- /dev/null +++ b/kernel/Documentation/watchdog/wdt.txt @@ -0,0 +1,50 @@ +Last Reviewed: 10/05/2007 + + WDT Watchdog Timer Interfaces For The Linux Operating System + Alan Cox <alan@lxorguk.ukuu.org.uk> + + ICS WDT501-P + ICS WDT501-P (no fan tachometer) + ICS WDT500-P + +All the interfaces provide /dev/watchdog, which when open must be written +to within a timeout or the machine will reboot. Each write delays the reboot +time another timeout. In the case of the software watchdog the ability to +reboot will depend on the state of the machines and interrupts. The hardware +boards physically pull the machine down off their own onboard timers and +will reboot from almost anything. + +A second temperature monitoring interface is available on the WDT501P cards. +This provides /dev/temperature. This is the machine internal temperature in +degrees Fahrenheit. Each read returns a single byte giving the temperature. + +The third interface logs kernel messages on additional alert events. + +The ICS ISA-bus wdt card cannot be safely probed for. Instead you need to +pass IO address and IRQ boot parameters. E.g.: + wdt.io=0x240 wdt.irq=11 + +Other "wdt" driver parameters are: + heartbeat Watchdog heartbeat in seconds (default 60) + nowayout Watchdog cannot be stopped once started (kernel + build parameter) + tachometer WDT501-P Fan Tachometer support (0=disable, default=0) + type WDT501-P Card type (500 or 501, default=500) + +Features +-------- + WDT501P WDT500P +Reboot Timer X X +External Reboot X X +I/O Port Monitor o o +Temperature X o +Fan Speed X o +Power Under X o +Power Over X o +Overheat X o + +The external event interfaces on the WDT boards are not currently supported. +Minor numbers are however allocated for it. + + +Example Watchdog Driver: see Documentation/watchdog/src/watchdog-simple.c |