From: Paul Walmsley <paul@xxxxxxxxx>
Date: Sun, 16 Jan 2011 21:08:13 +0530
Subject: [PATCH] OMAP: counter_32k: init clocksource as part of machine
timer init

Linus's master branch, currently at commit
1b59be2a6cdcb5a12e18d8315c07c94a624de48f ("Merge branch 'slab/urgent'
of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6"),
crashes during boot on OMAP4430 ES2.0 Panda:

[    0.000000] OMAP clockevent source: GPTIMER1 at 32768 Hz
[    0.000000] Unable to handle kernel NULL pointer dereference at virtual
address 00000000
[    0.000000] pgd = c0004000
[    0.000000] [00000000] *pgd=00000000
[    0.000000] Internal error: Oops: 80000005 [#1] SMP
[    0.000000] last sysfs file:
[    0.000000] Modules linked in:
[    0.000000] CPU: 0    Tainted: G        W    (2.6.37-07734-g2467802 #7)
[    0.000000] PC is at 0x0
[    0.000000] LR is at sched_clock_poll+0x2c/0x3c
[    0.000000] pc : [<00000000>]    lr : [<c0060b74>]    psr: 600001d3
[    0.000000] sp : c058bfd0  ip : c058a000  fp : 00000000
[    0.000000] r10: 00000000  r9 : 411fc092  r8 : 800330c8
[    0.000000] r7 : c05a08e0  r6 : c0034c48  r5 : c05ffc40  r4 : c0034c4c
[    0.000000] r3 : c05ffe6c  r2 : c05a0bc0  r1 : c059f098  r0 : 00000000
[    0.000000] Flags: nZCv  IRQs off  FIQs off  Mode SVC_32  ISA ARM
Segment kernel
[    0.000000] Control: 10c53c7f  Table: 8000404a  DAC: 00000017

This is due to the recent ARM init_sched_clock() changes and the late
initialization of the counter_32k clock source:

   http://marc.info/?l=linux-omap&m=129513468605208&w=2

Fix by initializing the counter_32k clocksource during the machine timer
initialization.

Reported-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Signed-off-by: Paul Walmsley <paul@xxxxxxxxx>
---
 arch/arm/mach-omap1/time.c               |    7 +++++++
 arch/arm/mach-omap2/timer-gp.c           |    8 ++++++--
 arch/arm/plat-omap/counter_32k.c         |    3 +--
 arch/arm/plat-omap/include/plat/common.h |    1 +
 4 files changed, 15 insertions(+), 4 deletions(-)

Index: linux-2.6/arch/arm/mach-omap1/time.c
===================================================================
--- linux-2.6.orig/arch/arm/mach-omap1/time.c	2011-01-12 12:31:44.000000000 +0530
+++ linux-2.6/arch/arm/mach-omap1/time.c	2011-01-18 15:17:03.804665705 +0530
@@ -244,6 +244,13 @@
 
 	omap_init_mpu_timer(rate);
 	omap_init_clocksource(rate);
+	/*
+	 * XXX Since this file seems to deal mostly with the MPU timer,
+	 * this doesn't seem like the correct place for the sync timer
+	 * clocksource init.
+	 */
+	if (!cpu_is_omap7xx() && !cpu_is_omap15xx())
+		omap_init_clocksource_32k();
 }
 
 struct sys_timer omap_timer = {
Index: linux-2.6/arch/arm/mach-omap2/timer-gp.c
===================================================================
--- linux-2.6.orig/arch/arm/mach-omap2/timer-gp.c	2011-01-12 12:31:44.000000000 +0530
+++ linux-2.6/arch/arm/mach-omap2/timer-gp.c	2011-01-18 15:18:18.484040595 +0530
@@ -42,6 +42,8 @@
 
 #include "timer-gp.h"
 
+#include <plat/common.h>
+
 /* MAX_GPTIMER_ID: number of GPTIMERs on the chip */
 #define MAX_GPTIMER_ID		12
 
@@ -178,8 +180,10 @@
  * instead, just leave default clocksource which uses the 32k
  * sync counter.  See clocksource setup in see plat-omap/common.c. 
  */
-
-static inline void __init omap2_gp_clocksource_init(void) {}
+static void __init omap2_gp_clocksource_init(void)
+{
+	omap_init_clocksource_32k();
+}
 #else
 /*
  * clocksource
Index: linux-2.6/arch/arm/plat-omap/counter_32k.c
===================================================================
--- linux-2.6.orig/arch/arm/plat-omap/counter_32k.c	2011-01-12 12:31:44.444122138 +0530
+++ linux-2.6/arch/arm/plat-omap/counter_32k.c	2011-01-18 15:17:03.804665705 +0530
@@ -160,7 +160,7 @@
 	*ts = *tsp;
 }
 
-static int __init omap_init_clocksource_32k(void)
+int __init omap_init_clocksource_32k(void)
 {
 	static char err[] __initdata = KERN_ERR
 			"%s: can't register clocksource!\n";
@@ -195,7 +195,6 @@
 	}
 	return 0;
 }
-arch_initcall(omap_init_clocksource_32k);
 
 #endif	/* !(defined(CONFIG_ARCH_OMAP730) || defined(CONFIG_ARCH_OMAP15XX)) */
 
Index: linux-2.6/arch/arm/plat-omap/include/plat/common.h
===================================================================
--- linux-2.6.orig/arch/arm/plat-omap/include/plat/common.h	2011-01-12 12:31:44.000000000 +0530
+++ linux-2.6/arch/arm/plat-omap/include/plat/common.h	2011-01-18 15:17:03.804665705 +0530
@@ -35,6 +35,7 @@
 
 extern void omap_map_common_io(void);
 extern struct sys_timer omap_timer;
+extern int __init omap_init_clocksource_32k(void);
 
 extern void omap_reserve(void);