from richard: update reboot code for the pi2

Reference: /n/atom/patch/applied/pi2reboot
Date: Mon Jan  4 17:53:29 CET 2016
Signed-off-by: quanstro@quanstro.net

--- /sys/src/9/bcm/fns.h	Mon Jan  4 17:53:14 2016
+++ /sys/src/9/bcm/fns.h	Mon Jan  4 17:53:16 2016
@@ -64,6 +64,7 @@
 extern void irqenable(int, void (*)(Ureg*, void*), void*);
 extern void intrcpushutdown(void);
 #define intrenable(i, f, a, b, n) irqenable((i), (f), (a))
+extern void intrshutdown(void);
 extern void intrsoff(void);
 extern int l2ap(int);
 extern void l2cacheuwbinv(void);
--- /sys/src/9/bcm/main.c	Mon Jan  4 17:53:18 2016
+++ /sys/src/9/bcm/main.c	Mon Jan  4 17:53:19 2016
@@ -659,6 +659,11 @@
 	if (m->machno != 0)
 		procwired(up, 0);
 
+	/* setup reboot trampoline function */
+	f = (void*)REBOOTADDR;
+	memmove(f, rebootcode, sizeof(rebootcode));
+	cachedwbse(f, sizeof(rebootcode));
+
 	shutdown(0);
 
 	/*
@@ -684,15 +689,11 @@
 	clockshutdown();
 
 	splfhi();
-	intrsoff();
+	intrshutdown();
 
-	/* setup reboot trampoline function */
-	f = (void*)REBOOTADDR;
-	memmove(f, rebootcode, sizeof(rebootcode));
+	/* off we go - never to return */
 	cacheuwbinv();
 	l2cacheuwbinv();
-
-	/* off we go - never to return */
 	(*f)(PADDR(entry), PADDR(code), size);
 
 	iprint("loaded kernel returned!\n");