diff options
Diffstat (limited to 'Documentation/watchdog')
| -rw-r--r-- | Documentation/watchdog/convert_drivers_to_kernel_api.txt | 218 | ||||
| -rw-r--r-- | Documentation/watchdog/hpwdt.txt | 95 | ||||
| -rw-r--r-- | Documentation/watchdog/pcwd-watchdog.txt | 83 | ||||
| -rw-r--r-- | Documentation/watchdog/src/.gitignore | 2 | ||||
| -rw-r--r-- | Documentation/watchdog/src/Makefile | 8 | ||||
| -rw-r--r-- | Documentation/watchdog/src/watchdog-simple.c | 24 | ||||
| -rw-r--r-- | Documentation/watchdog/src/watchdog-test.c | 86 | ||||
| -rw-r--r-- | Documentation/watchdog/watchdog-api.txt | 316 | ||||
| -rw-r--r-- | Documentation/watchdog/watchdog-kernel-api.txt | 226 | ||||
| -rw-r--r-- | Documentation/watchdog/watchdog-parameters.txt | 399 | ||||
| -rw-r--r-- | Documentation/watchdog/watchdog.txt | 115 | ||||
| -rw-r--r-- | Documentation/watchdog/wdt.txt | 50 |
12 files changed, 1182 insertions, 440 deletions
diff --git a/Documentation/watchdog/convert_drivers_to_kernel_api.txt b/Documentation/watchdog/convert_drivers_to_kernel_api.txt new file mode 100644 index 00000000000..271b8850dde --- /dev/null +++ b/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/Documentation/watchdog/hpwdt.txt b/Documentation/watchdog/hpwdt.txt new file mode 100644 index 00000000000..9488078900e --- /dev/null +++ b/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/Documentation/watchdog/pcwd-watchdog.txt b/Documentation/watchdog/pcwd-watchdog.txt index 12187a33e31..4f68052395c 100644 --- a/Documentation/watchdog/pcwd-watchdog.txt +++ b/Documentation/watchdog/pcwd-watchdog.txt @@ -1,3 +1,5 @@ +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> @@ -14,86 +16,17 @@ 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 the PC - Watchdog program, available from http://ftp.bitgate.com/pcwd/. + 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 do the following: - --- Snippet of code -- -/* - * Watchdog Driver Test Program - */ - -#include <stdio.h> -#include <stdlib.h> -#include <string.h> -#include <unistd.h> -#include <fcntl.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. - */ -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. - */ -int main(int argc, char *argv[]) -{ - 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)) { - ioctl(fd, WDIOC_SETOPTIONS, WDIOS_DISABLECARD); - fprintf(stderr, "Watchdog card disabled.\n"); - fflush(stderr); - exit(0); - } else if (!strncasecmp(argv[1], "-e", 2)) { - ioctl(fd, WDIOC_SETOPTIONS, WDIOS_ENABLECARD); - fprintf(stderr, "Watchdog card enabled.\n"); - fflush(stderr); - exit(0); - } else { - fprintf(stderr, "-d to disable, -e to enable.\n"); - fprintf(stderr, "run by itself to tick the card.\n"); - fflush(stderr); - exit(0); - } - } else { - fprintf(stderr, "Watchdog Ticking Away!\n"); - fflush(stderr); - } - - while(1) { - keep_alive(); - sleep(1); - } -} --- End snippet -- + driver, simply use of modify the watchdog test program: + Documentation/watchdog/src/watchdog-test.c + Other IOCTL functions include: @@ -131,5 +64,3 @@ int main(int argc, char *argv[]) -- Ken Hollis (kenji@bitgate.com) -(This documentation may be out of date. Check - http://ftp.bitgate.com/pcwd/ for the absolute latest additions.) diff --git a/Documentation/watchdog/src/.gitignore b/Documentation/watchdog/src/.gitignore new file mode 100644 index 00000000000..ac90997dba9 --- /dev/null +++ b/Documentation/watchdog/src/.gitignore @@ -0,0 +1,2 @@ +watchdog-simple +watchdog-test diff --git a/Documentation/watchdog/src/Makefile b/Documentation/watchdog/src/Makefile new file mode 100644 index 00000000000..40e5f46e474 --- /dev/null +++ b/Documentation/watchdog/src/Makefile @@ -0,0 +1,8 @@ +# kbuild trick to avoid linker error. Can be omitted if a module is built. +obj- := dummy.o + +# List of programs to build +hostprogs-y := watchdog-simple watchdog-test + +# Tell kbuild to always build the programs +always := $(hostprogs-y) diff --git a/Documentation/watchdog/src/watchdog-simple.c b/Documentation/watchdog/src/watchdog-simple.c new file mode 100644 index 00000000000..ba45803a221 --- /dev/null +++ b/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/Documentation/watchdog/src/watchdog-test.c b/Documentation/watchdog/src/watchdog-test.c new file mode 100644 index 00000000000..3da822967ee --- /dev/null +++ b/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/Documentation/watchdog/watchdog-api.txt b/Documentation/watchdog/watchdog-api.txt index c5beb548cfc..eb7132ed8bb 100644 --- a/Documentation/watchdog/watchdog-api.txt +++ b/Documentation/watchdog/watchdog-api.txt @@ -1,3 +1,6 @@ +Last reviewed: 10/05/2007 + + The Linux Watchdog driver API. Copyright 2002 Christer Weingel <wingel@nano-system.com> @@ -22,7 +25,7 @@ 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 +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. @@ -34,38 +37,32 @@ 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: - -int main(int argc, const char *argv[]) { - int fd=open("/dev/watchdog",O_WRONLY); - if (fd==-1) { - perror("watchdog"); - exit(1); - } - while(1) { - write(fd, "\0", 1); - sleep(10); - } -} +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. 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 dameon crashes, the system -will reboot after the timeout has passed. - -Some other drivers will not disable the watchdog, unless a specific -magic character 'V' has been sent /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. +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: @@ -107,7 +104,40 @@ current timeout using the GETTIMEOUT ioctl. ioctl(fd, WDIOC_GETTIMEOUT, &timeout); printf("The timeout was is %d seconds\n", timeout); -Envinronmental monitoring: +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 pretimout will go of 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 @@ -166,6 +196,10 @@ 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 @@ -182,17 +216,16 @@ 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 farenheit. +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; right now the pcwd driver is the only one -supporting thiss ioctl. +the cards operation. int options = 0; - ioctl(fd, WDIOC_SETOPTIONS, options); + ioctl(fd, WDIOC_SETOPTIONS, &options); The following options are available: @@ -202,218 +235,3 @@ The following options are available: [FIXME -- better explanations] -Implementations in the current drivers in the kernel tree: - -Here I have tried to summarize what the different drivers support and -where they do strange things compared to the other drivers. - -acquirewdt.c -- Acquire Single Board Computer - - This driver has a hardcoded timeout of 1 minute - - Supports CONFIG_WATCHDOG_NOWAYOUT - - GETSUPPORT returns KEEPALIVEPING. GETSTATUS will return 1 if - the device is open, 0 if not. [FIXME -- isn't this rather - silly? To be able to use the ioctl, the device must be open - and so GETSTATUS will always return 1]. - -advantechwdt.c -- Advantech Single Board Computer - - Timeout that defaults to 60 seconds, supports SETTIMEOUT. - - Supports CONFIG_WATCHDOG_NOWAYOUT - - GETSUPPORT returns WDIOF_KEEPALIVEPING and WDIOF_SETTIMEOUT. - The GETSTATUS call returns if the device is open or not. - [FIXME -- silliness again?] - -booke_wdt.c -- PowerPC BookE Watchdog Timer - - Timeout default varies according to frequency, supports - SETTIMEOUT - - Watchdog can not be turned off, CONFIG_WATCHDOG_NOWAYOUT - does not make sense - - GETSUPPORT returns the watchdog_info struct, and - GETSTATUS returns the supported options. GETBOOTSTATUS - returns a 1 if the last reset was caused by the - watchdog and a 0 otherwise. This watchdog can not be - disabled once it has been started. The wdt_period kernel - parameter selects which bit of the time base changing - from 0->1 will trigger the watchdog exception. Changing - the timeout from the ioctl calls will change the - wdt_period as defined above. Finally if you would like to - replace the default Watchdog Handler you can implement the - WatchdogHandler() function in your own code. - -eurotechwdt.c -- Eurotech CPU-1220/1410 - - The timeout can be set using the SETTIMEOUT ioctl and defaults - to 60 seconds. - - Also has a module parameter "ev", event type which controls - what should happen on a timeout, the string "int" or anything - else that causes a reboot. [FIXME -- better description] - - Supports CONFIG_WATCHDOG_NOWAYOUT - - GETSUPPORT returns CARDRESET and WDIOF_SETTIMEOUT but - GETSTATUS is not supported and GETBOOTSTATUS just returns 0. - -i810-tco.c -- Intel 810 chipset - - Also has support for a lot of other i8x0 stuff, but the - watchdog is one of the things. - - The timeout is set using the module parameter "i810_margin", - which is in steps of 0.6 seconds where 2<i810_margin<64. The - driver supports the SETTIMEOUT ioctl. - - Supports CONFIG_WATCHDOG_NOWAYOUT. - - GETSUPPORT returns WDIOF_SETTIMEOUT. The GETSTATUS call - returns some kind of timer value which ist not compatible with - the other drivers. GETBOOT status returns some kind of - hardware specific boot status. [FIXME -- describe this] - -ib700wdt.c -- IB700 Single Board Computer - - Default timeout of 30 seconds and the timeout is settable - using the SETTIMEOUT ioctl. Note that only a few timeout - values are supported. - - Supports CONFIG_WATCHDOG_NOWAYOUT - - GETSUPPORT returns WDIOF_KEEPALIVEPING and WDIOF_SETTIMEOUT. - The GETSTATUS call returns if the device is open or not. - [FIXME -- silliness again?] - -machzwd.c -- MachZ ZF-Logic - - Hardcoded timeout of 10 seconds - - Has a module parameter "action" that controls what happens - when the timeout runs out which can be 0 = RESET (default), - 1 = SMI, 2 = NMI, 3 = SCI. - - Supports CONFIG_WATCHDOG_NOWAYOUT and the magic character - 'V' close handling. - - GETSUPPORT returns WDIOF_KEEPALIVEPING, and the GETSTATUS call - returns if the device is open or not. [FIXME -- silliness - again?] - -mixcomwd.c -- MixCom Watchdog - - [FIXME -- I'm unable to tell what the timeout is] - - Supports CONFIG_WATCHDOG_NOWAYOUT - - GETSUPPORT returns WDIOF_KEEPALIVEPING, GETSTATUS returns if - the device is opened or not [FIXME -- I'm not really sure how - this works, there seems to be some magic connected to - CONFIG_WATCHDOG_NOWAYOUT] - -pcwd.c -- Berkshire PC Watchdog - - Hardcoded timeout of 1.5 seconds - - Supports CONFIG_WATCHDOG_NOWAYOUT - - GETSUPPORT returns WDIOF_OVERHEAT|WDIOF_CARDRESET and both - GETSTATUS and GETBOOTSTATUS return something useful. - - The SETOPTIONS call can be used to enable and disable the card - and to ask the driver to call panic if the system overheats. - -sbc60xxwdt.c -- 60xx Single Board Computer - - Hardcoded timeout of 10 seconds - - Does not support CONFIG_WATCHDOG_NOWAYOUT, but has the magic - character 'V' close handling. - - No bits set in GETSUPPORT - -scx200.c -- National SCx200 CPUs - - Not in the kernel yet. - - The timeout is set using a module parameter "margin" which - defaults to 60 seconds. The timeout can also be set using - SETTIMEOUT and read using GETTIMEOUT. - - Supports a module parameter "nowayout" that is initialized - with the value of CONFIG_WATCHDOG_NOWAYOUT. Also supports the - magic character 'V' handling. - -shwdt.c -- SuperH 3/4 processors - - [FIXME -- I'm unable to tell what the timeout is] - - Supports CONFIG_WATCHDOG_NOWAYOUT - - GETSUPPORT returns WDIOF_KEEPALIVEPING, and the GETSTATUS call - returns if the device is open or not. [FIXME -- silliness - again?] - -softdog.c -- Software watchdog - - The timeout is set with the module parameter "soft_margin" - which defaults to 60 seconds, the timeout is also settable - using the SETTIMEOUT ioctl. - - Supports CONFIG_WATCHDOG_NOWAYOUT - - WDIOF_SETTIMEOUT bit set in GETSUPPORT - -w83877f_wdt.c -- W83877F Computer - - Hardcoded timeout of 30 seconds - - Does not support CONFIG_WATCHDOG_NOWAYOUT, but has the magic - character 'V' close handling. - - No bits set in GETSUPPORT - -w83627hf_wdt.c -- w83627hf watchdog - - Timeout that defaults to 60 seconds, supports SETTIMEOUT. - - Supports CONFIG_WATCHDOG_NOWAYOUT - - GETSUPPORT returns WDIOF_KEEPALIVEPING and WDIOF_SETTIMEOUT. - The GETSTATUS call returns if the device is open or not. - -wdt.c -- ICS WDT500/501 ISA and -wdt_pci.c -- ICS WDT500/501 PCI - - Default timeout of 60 seconds. The timeout is also settable - using the SETTIMEOUT ioctl. - - Supports CONFIG_WATCHDOG_NOWAYOUT - - GETSUPPORT returns with bits set depending on the actual - card. The WDT501 supports a lot of external monitoring, the - WDT500 much less. - -wdt285.c -- Footbridge watchdog - - The timeout is set with the module parameter "soft_margin" - which defaults to 60 seconds. The timeout is also settable - using the SETTIMEOUT ioctl. - - Does not support CONFIG_WATCHDOG_NOWAYOUT - - WDIOF_SETTIMEOUT bit set in GETSUPPORT - -wdt977.c -- Netwinder W83977AF chip - - Hardcoded timeout of 3 minutes - - Supports CONFIG_WATCHDOG_NOWAYOUT - - Does not support any ioctls at all. - diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt new file mode 100644 index 00000000000..a0438f3957c --- /dev/null +++ b/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/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt new file mode 100644 index 00000000000..692791cc674 --- /dev/null +++ b/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/Documentation/watchdog/watchdog.txt b/Documentation/watchdog/watchdog.txt deleted file mode 100644 index dffda29c879..00000000000 --- a/Documentation/watchdog/watchdog.txt +++ /dev/null @@ -1,115 +0,0 @@ - Watchdog Timer Interfaces For The Linux Operating System - - Alan Cox <alan@lxorguk.ukuu.org.uk> - - Custom Linux Driver And Program Development - - -The following watchdog drivers are currently implemented: - - ICS WDT501-P - ICS WDT501-P (no fan tachometer) - ICS WDT500-P - Software Only - SA1100 Internal Watchdog - Berkshire Products PC Watchdog Revision A & C (by Ken Hollis) - - -All six 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 -and some Berkshire 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. - -Both software and hardware watchdog drivers are available in the standard -kernel. If you are using the software watchdog, you probably also want -to use "panic=60" as a boot argument as well. - -The wdt card cannot be safely probed for. Instead you need to pass -wdt=ioaddr,irq as a boot parameter - eg "wdt=0x240,11". - -The SA1100 watchdog module can be configured with the "sa1100_margin" -commandline argument which specifies timeout value in seconds. - -The i810 TCO watchdog modules can be configured with the "i810_margin" -commandline argument which specifies the counter initial value. The counter -is decremented every 0.6 seconds and default to 50 (30 seconds). Values can -range between 3 and 63. - -The i810 TCO watchdog driver also implements the WDIOC_GETSTATUS and -WDIOC_GETBOOTSTATUS ioctl()s. WDIOC_GETSTATUS returns the actual counter value -and WDIOC_GETBOOTSTATUS returns the value of TCO2 Status Register (see Intel's -documentation for the 82801AA and 82801AB datasheet). - -Features --------- - WDT501P WDT500P Software Berkshire i810 TCO SA1100WD -Reboot Timer X X X X X X -External Reboot X X o o o X -I/O Port Monitor o o o X o o -Temperature X o o X o o -Fan Speed X o o o o o -Power Under X o o o o o -Power Over X o o o o o -Overheat X o o o o o - -The external event interfaces on the WDT boards are not currently supported. -Minor numbers are however allocated for it. - - -Example Watchdog Driver ------------------------ - -#include <stdio.h> -#include <unistd.h> -#include <fcntl.h> - -int main(int argc, const char *argv[]) -{ - int fd=open("/dev/watchdog",O_WRONLY); - if(fd==-1) - { - perror("watchdog"); - exit(1); - } - while(1) - { - write(fd,"\0",1); - fsync(fd); - sleep(10); - } -} - - -Contact Information - -People keep asking about the WDT watchdog timer hardware: The phone contacts -for Industrial Computer Source are: - -Industrial Computer Source -http://www.indcompsrc.com -ICS Advent, San Diego -6260 Sequence Dr. -San Diego, CA 92121-4371 -Phone (858) 677-0877 -FAX: (858) 677-0895 -> -ICS Advent Europe, UK -Oving Road -Chichester, -West Sussex, -PO19 4ET, UK -Phone: 00.44.1243.533900 - - -and please mention Linux when enquiring. - -For full information about the PCWD cards see the pcwd-watchdog.txt document. diff --git a/Documentation/watchdog/wdt.txt b/Documentation/watchdog/wdt.txt new file mode 100644 index 00000000000..061c2e35384 --- /dev/null +++ b/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 |