PERFORCE change 103389 for review

[Warner Losh]

http://perforce.freebsd.org/chv.cgi?CH=103389

Change 103389 by imp at imp_bugs on 2006/08/07 19:04:23

	Implement watchdog.  The OS has 30s to load and get to the point
	of disabling the watchdog before we reboot.  64s is the absolute
	max, and 30s seemed a good number.  Usually it takes like 5s-10s.

Affected files ...

.. //depot/projects/arm/src/sys/boot/arm/at91/libat91/lib.h#13 edit
.. //depot/projects/arm/src/sys/boot/arm/at91/libat91/reset.c#2 edit

Differences ...

==== //depot/projects/arm/src/sys/boot/arm/at91/libat91/lib.h#13 (text) ====

@@ -40,7 +40,8 @@
 /* XMODEM protocol */
 int xmodem_rx(char *dst);
 
-/* Reboot! Reset! */
+/*  */
+void start_wdog(void);
 void reset(void);
 
 /* Delay us */

==== //depot/projects/arm/src/sys/boot/arm/at91/libat91/reset.c#2 (text+ko) ====

@@ -28,10 +28,11 @@
 #include "lib.h"
 
 /*
- * int getc(int seconds)
+ * void reset()
  * 
- * Reads a character from the DBGU port, if one is available within about
- * seconds seconds.  It assumes that DBGU has already been initialized.
+ * Forces a reset of the system.  Uses watchdog timer of '1', which
+ * corresponds to 128 / SLCK seconds (SLCK is 32,768 Hz, so 128/32768 is
+ * 1 / 256 ~= 5.4ms
  */
 void
 reset(void)
@@ -40,3 +41,17 @@
 	AT91C_BASE_ST->ST_WDMR = 1 | AT91C_ST_RSTEN;
 	AT91C_BASE_ST->ST_CR = AT91C_ST_WDRST;
 }
+
+/*
+ * void start_wdog()
+ *
+ * Starts a watchdog timer.  We force the boot process to get to the point
+ * it can kick the watch dog part of the ST part for the OS's driver.
+ */
+void
+start_wdog(void)
+{
+	// The following should effect a reset after 30 seconds.
+	AT91C_BASE_ST->ST_WDMR = (30 * (32768 / 128)) | AT91C_ST_RSTEN;
+	AT91C_BASE_ST->ST_CR = AT91C_ST_WDRST;
+}