[PATCH] Watchdog: Winsystems EPX-C3 SBC

This is a 2.6 patch that adds support for the watchdog timer built into the
EPX-C3 single board computer manufactured by Winsystems, Inc.

Driver details:

This is for x86 only.  This watchdog is pretty basic and simple.  It is
only configurable via jumpers on the SBC, and it only has either a 1.5s or
200s interval.  The watchdog can either be auto-configured to start as soon
as the machine powers up (bad idea for the 1.5s interval!) or it can be
enabled and disabled by writing to io port 0x1ee.  Petting the watchdog
involves writing any value to io port 0x1ef.

The only unfortunate thing about this watchdog (and it is not at all
uncommmon in watchdogs that linux supports) is that it is not a PCI or
ISA-PNP device and as such it isn't at all probeable.  Either the watchdog
exists as 2 bytes at 0x1ee, or it doesn't.  Thus, using this driver on a
machine that doesn't have that watchdog can potentially hang/crash the
system, etc.  So only use this driver if you in fact are on a Winsystems
EPX-C3 SBC.

Anyway this driver fits into the already-existing watchdog framework quite
nicely and I already tested it on my EPX-C3 and it works like a charm.

Signed-off-by: Calin A. Culianu <calin@ajvar.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/char/watchdog/Kconfig b/drivers/char/watchdog/Kconfig
index a6544790af60..f68aaa60fa8f 100644
--- a/drivers/char/watchdog/Kconfig
+++ b/drivers/char/watchdog/Kconfig
@@ -395,6 +395,28 @@ config MACHZ_WDT
           To compile this driver as a module, choose M here: the
           module will be called machzwd.
 
+config SBC_EPX_C3_WATCHDOG
+        tristate "Winsystems SBC EPX-C3 watchdog"
+        depends on WATCHDOG && X86
+        ---help---
+          This is the driver for the built-in watchdog timer on the EPX-C3
+          Single-board computer made by Winsystems, Inc.
+
+          *Note*: This hardware watchdog is not probeable and thus there
+          is no way to know if writing to its IO address will corrupt
+          your system or have any real effect.  The only way to be sure
+          that this driver does what you want is to make sure you
+          are runnning it on an EPX-C3 from Winsystems with the watchdog
+          timer at IO address 0x1ee and 0x1ef.  It will write to both those
+          IO ports.  Basically, the assumption is made that if you compile
+          this driver into your kernel and/or load it as a module, that you
+          know what you are doing and that you are in fact running on an
+          EPX-C3 board!
+
+          To compile this driver as a module, choose M here: the
+          module will be called sbc_epx_c3.
+
+
 # PowerPC Architecture
 
 config 8xx_WDT