[PATCH] ppc32: m8xx watchdog update

This updates m8xx_wdt as follows:

1) Remove now obsolete fpos check in the write() function. The driver is
currently non functional due to this bug.

2) Use in/out macros for register access.

3) Allows m8xx_wdt to use a kernel timer instead of the builtin RTC/PIT
for keep-alive trigger (which is responsible for servicing the watchdog
until an userspace application takes over). For instance Cyclades PRxK
boards (MPC 855T based) have a non-functional internal RTC/PIT unit.
Behaviour for boards with RTC/PIT is unchaged.

4) The last change required moving the RTCSC register setting code
to a weak function which can be overriden by board specific files.
Otherwise the timer init code trashes the register making it impossible
for m8xx_wdt to detect the situation.

Signed-off-by: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/ppc/syslib/m8xx_wdt.h b/arch/ppc/syslib/m8xx_wdt.h
index 0d81a9f..e75835f 100644
--- a/arch/ppc/syslib/m8xx_wdt.h
+++ b/arch/ppc/syslib/m8xx_wdt.h
@@ -9,8 +9,12 @@
 #ifndef _PPC_SYSLIB_M8XX_WDT_H
 #define _PPC_SYSLIB_M8XX_WDT_H
 
+extern int m8xx_has_internal_rtc;
+
 extern void m8xx_wdt_handler_install(bd_t * binfo);
 extern int m8xx_wdt_get_timeout(void);
 extern void m8xx_wdt_reset(void);
+extern void m8xx_wdt_install_timer(void);
+extern void m8xx_wdt_stop_timer(void);
 
 #endif				/* _PPC_SYSLIB_M8XX_WDT_H */