Re: State of LDP3430 platform

Paul Walmsley
2011-01-16T04:32:04Z

On Sat, 15 Jan 2011, Russell King - ARM Linux wrote:

> On Sat, Jan 15, 2011 at 12:38:46PM -0700, Paul Walmsley wrote:
> > On Fri, 14 Jan 2011, Tony Lindgren wrote:
> >
> > > * Paul Walmsley <paul@pwsan.com> [101207 19:30]:
> > > > On Tue, 7 Dec 2010, Paul Walmsley wrote:
> > > >
> > > > Regarding the watchdog problem, unfortunately, I can't reproduce on the
> > > > BeagleBoard with v2.6.37-rc5 with either omap2plus_defconfig or
> > > > omap2plus_defconfig without CONFIG_WATCHDOG. If you send along your
> > > > .config, one of us can try to reproduce the problem with it. Do the
> > > > 2.6.38 hwmod and wdt patchsets fix the problem for .38, at least?
> > >
> > > I've been seeing this on my omap4 panda. While debugging it, I left
> > > u-boot console only running for a few minutes to see if that stays up.
> > > It did.. And after doing that somehow now my panda boots all the way
> > > and stays up. Weird.
> >
> > Hmmm, do you think the watchdog is what's killing it? I don't think
> > leaving u-boot running would affect that?
>
> Right, well, the LDP3430 (and probably all OMAP) is broken by my
> init_sched_clock() changes because I gave up with testing on OMAP
> platforms.
>
> Why does OMAP initialize its clock sources soo late, outside of
> the timer initialization? This means you have no counter in place
> (except for the jiffies counter) during early boot.
>
> Is there a reason why OMAP uniquely does this?

I don't think so.

Patch attached.

- Paul

[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@arm.linux.org.uk>
Signed-off-by: Paul Walmsley <paul@pwsan.com>

---
arch/arm/mach-omap1/time.c | 7 +++++++
arch/arm/mach-omap2/timer-gp.c | 10 ++++++++--
arch/arm/plat-omap/counter_32k.c | 3 +--
arch/arm/plat-omap/include/plat/common.h | 1 +
4 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mach-omap1/time.c b/arch/arm/mach-omap1/time.c
index ed7a61f..6ec65e5 100644
--- a/arch/arm/mach-omap1/time.c
+++ b/arch/arm/mach-omap1/time.c
@@ -244,6 +244,13 @@ static void __init omap_timer_init(void)

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 = {
diff --git a/arch/arm/mach-omap2/timer-gp.c b/arch/arm/mach-omap2/timer-gp.c
index 4e48e78..57d53e0 100644
--- a/arch/arm/mach-omap2/timer-gp.c
+++ b/arch/arm/mach-omap2/timer-gp.c
@@ -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

@@ -176,10 +178,14 @@ static void __init omap2_gp_clockevent_init(void)
/*
* When 32k-timer is enabled, don't use GPTimer for clocksource
* instead, just leave default clocksource which uses the 32k
- * sync counter. See clocksource setup in see plat-omap/common.c.
+ * sync counter. See clocksource setup in plat-omap/timer-32k.c
*/

-static inline void __init omap2_gp_clocksource_init(void) {}
+static void __init omap2_gp_clocksource_init(void)
+{
+ omap_init_clocksource_32k();
+}
+
#else
/*
* clocksource
diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c
index ea46440..0367998 100644
--- a/arch/arm/plat-omap/counter_32k.c
+++ b/arch/arm/plat-omap/counter_32k.c
@@ -160,7 +160,7 @@ void read_persistent_clock(struct timespec *ts)
*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 @@ static int __init omap_init_clocksource_32k(void)
}
return 0;
}
-arch_initcall(omap_init_clocksource_32k);

#endif /* !(defined(CONFIG_ARCH_OMAP730) || defined(CONFIG_ARCH_OMAP15XX)) */

diff --git a/arch/arm/plat-omap/include/plat/common.h b/arch/arm/plat-omap/include/plat/common.h
index 6b8088e..84c707f 100644
--- a/arch/arm/plat-omap/include/plat/common.h
+++ b/arch/arm/plat-omap/include/plat/common.h
@@ -35,6 +35,7 @@ struct sys_timer;

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);

--
1.7.2.3