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authorKumar Gala <galak@freescale.com>2005-09-03 18:55:33 -0400
committerLinus Torvalds <torvalds@evo.osdl.org>2005-09-05 03:05:56 -0400
commita2f40ccd294d14e5aca464c1913e8e0d8de35fca (patch)
treed900ebdbf37656d77acf7934db40021b21d49fde /Documentation/watchdog/watchdog-api.txt
parent886b9fa49900b055e20cd98f379fda49835d1ee6 (diff)
[PATCH] ppc32: Added support for the Book-E style Watchdog Timer
PowerPC 40x and Book-E processors support a watchdog timer at the processor core level. The timer has implementation dependent timeout frequencies that can be configured by software. One the first Watchdog timeout we get a critical exception. It is left to board specific code to determine what should happen at this point. If nothing is done and another timeout period expires the processor may attempt to reset the machine. Command line parameters: wdt=0 : disable watchdog (default) wdt=1 : enable watchdog wdt_period=N : N sets the value of the Watchdog Timer Period. The Watchdog Timer Period meaning is implementation specific. Check User Manual for the processor for more details. This patch is based off of work done by Takeharu Kato. Signed-off-by: Matt McClintock <msm@freescale.com> Signed-off-by: Kumar Gala <kumar.gala@freescale.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'Documentation/watchdog/watchdog-api.txt')
-rw-r--r--Documentation/watchdog/watchdog-api.txt20
1 files changed, 20 insertions, 0 deletions
diff --git a/Documentation/watchdog/watchdog-api.txt b/Documentation/watchdog/watchdog-api.txt
index 28388aa700c6..c5beb548cfc4 100644
--- a/Documentation/watchdog/watchdog-api.txt
+++ b/Documentation/watchdog/watchdog-api.txt
@@ -228,6 +228,26 @@ advantechwdt.c -- Advantech Single Board Computer
228 The GETSTATUS call returns if the device is open or not. 228 The GETSTATUS call returns if the device is open or not.
229 [FIXME -- silliness again?] 229 [FIXME -- silliness again?]
230 230
231booke_wdt.c -- PowerPC BookE Watchdog Timer
232
233 Timeout default varies according to frequency, supports
234 SETTIMEOUT
235
236 Watchdog can not be turned off, CONFIG_WATCHDOG_NOWAYOUT
237 does not make sense
238
239 GETSUPPORT returns the watchdog_info struct, and
240 GETSTATUS returns the supported options. GETBOOTSTATUS
241 returns a 1 if the last reset was caused by the
242 watchdog and a 0 otherwise. This watchdog can not be
243 disabled once it has been started. The wdt_period kernel
244 parameter selects which bit of the time base changing
245 from 0->1 will trigger the watchdog exception. Changing
246 the timeout from the ioctl calls will change the
247 wdt_period as defined above. Finally if you would like to
248 replace the default Watchdog Handler you can implement the
249 WatchdogHandler() function in your own code.
250
231eurotechwdt.c -- Eurotech CPU-1220/1410 251eurotechwdt.c -- Eurotech CPU-1220/1410
232 252
233 The timeout can be set using the SETTIMEOUT ioctl and defaults 253 The timeout can be set using the SETTIMEOUT ioctl and defaults