[PATCH] mach-shmobile: r8a7779 SMP TWD boot regression fix

[PATCH] mach-shmobile: r8a7779 SMP TWD boot regression fix

[Magnus Damm]

From: Magnus Damm <damm@opensource.se>

Fix SMP TWD boot regression on r8a7779 based platforms caused by:

4200b16 ARM: shmobile: convert to twd_local_timer_register() interface

After the merge of the above commit it has been impossible to boot
r8a7779 based SoCs with SMP enabled and CONFIG_HAVE_ARM_TWD=y. The
kernel crashes at smp_init_cpus() timing which is before the console
has been initialized, so to the user this looks like a kernel lock up
without any particular error message.

This patch fixes the regression on r8a7779 by moving the TWD
registration code from smp_init_cpus() to sys_timer->init() time. 

Signed-off-by: Magnus Damm <damm@opensource.se>
---

 Fixes 3.4-rc regression.

 Tested on the r8a7779 Marzen board on top of post v3.4-rc6:
 7ee94d97aafacf5a019b3578e0eae6daa2e2bcd5

 arch/arm/mach-shmobile/include/mach/common.h |    1 +
 arch/arm/mach-shmobile/setup-r8a7779.c       |    4 ++++
 arch/arm/mach-shmobile/smp-r8a7779.c         |    8 +++++++-
 3 files changed, 12 insertions(+), 1 deletion(-)

--- 0001/arch/arm/mach-shmobile/include/mach/common.h
+++ work/arch/arm/mach-shmobile/include/mach/common.h	2012-05-10 14:27:12.000000000 +0900
@@ -82,5 +82,6 @@ extern int r8a7779_platform_cpu_kill(uns
 extern void r8a7779_secondary_init(unsigned int cpu);
 extern int r8a7779_boot_secondary(unsigned int cpu);
 extern void r8a7779_smp_prepare_cpus(void);
+extern void r8a7779_register_twd(void);
 
 #endif /* __ARCH_MACH_COMMON_H */
--- 0001/arch/arm/mach-shmobile/setup-r8a7779.c
+++ work/arch/arm/mach-shmobile/setup-r8a7779.c	2012-05-10 14:33:41.000000000 +0900
@@ -262,10 +262,14 @@ void __init r8a7779_add_standard_devices
 			    ARRAY_SIZE(r8a7779_late_devices));
 }
 
+/* do nothing for !CONFIG_SMP or !CONFIG_HAVE_TWD */
+void __init __weak r8a7779_register_twd(void) { }
+
 static void __init r8a7779_earlytimer_init(void)
 {
 	r8a7779_clock_init();
 	shmobile_earlytimer_init();
+	r8a7779_register_twd();
 }
 
 void __init r8a7779_add_early_devices(void)
--- 0001/arch/arm/mach-shmobile/smp-r8a7779.c
+++ work/arch/arm/mach-shmobile/smp-r8a7779.c	2012-05-10 14:31:32.000000000 +0900
@@ -64,8 +64,15 @@ static void __iomem *scu_base_addr(void)
 static DEFINE_SPINLOCK(scu_lock);
 static unsigned long tmp;
 
+#ifdef CONFIG_HAVE_ARM_TWD
 static DEFINE_TWD_LOCAL_TIMER(twd_local_timer, 0xf0000600, 29);
 
+void __init r8a7779_register_twd(void)
+{
+	twd_local_timer_register(&twd_local_timer);
+}
+#endif
+
 static void modify_scu_cpu_psr(unsigned long set, unsigned long clr)
 {
 	void __iomem *scu_base = scu_base_addr();
@@ -84,7 +91,6 @@ unsigned int __init r8a7779_get_core_cou
 {
 	void __iomem *scu_base = scu_base_addr();
 
-	shmobile_twd_init(&twd_local_timer);
 	return scu_get_core_count(scu_base);
 }
 

Re: [PATCH] mach-shmobile: r8a7779 SMP TWD boot regression fix

[Marc Zyngier]

Hi Magnus,

On 10/05/12 06:57, Magnus Damm wrote:
> From: Magnus Damm <damm@opensource.se>
> 
> Fix SMP TWD boot regression on r8a7779 based platforms caused by:
> 
> 4200b16 ARM: shmobile: convert to twd_local_timer_register() interface
> 
> After the merge of the above commit it has been impossible to boot
> r8a7779 based SoCs with SMP enabled and CONFIG_HAVE_ARM_TWD=y. The
> kernel crashes at smp_init_cpus() timing which is before the console
> has been initialized, so to the user this looks like a kernel lock up
> without any particular error message.
> 
> This patch fixes the regression on r8a7779 by moving the TWD
> registration code from smp_init_cpus() to sys_timer->init() time. 
> 
> Signed-off-by: Magnus Damm <damm@opensource.se>

I'm a bit confused here. Does sh73a0 work OK? If so, why is the behavior
any different?

	M.
-- 
Jazz is not dead. It just smells funny...

Re: [PATCH] mach-shmobile: r8a7779 SMP TWD boot regression fix

[Magnus Damm]

On Thu, May 10, 2012 at 7:03 PM, Marc Zyngier <marc.zyngier@arm.com> wrote:
> Hi Magnus,
>
> On 10/05/12 06:57, Magnus Damm wrote:
>> From: Magnus Damm <damm@opensource.se>
>>
>> Fix SMP TWD boot regression on r8a7779 based platforms caused by:
>>
>> 4200b16 ARM: shmobile: convert to twd_local_timer_register() interface
>>
>> After the merge of the above commit it has been impossible to boot
>> r8a7779 based SoCs with SMP enabled and CONFIG_HAVE_ARM_TWD=y. The
>> kernel crashes at smp_init_cpus() timing which is before the console
>> has been initialized, so to the user this looks like a kernel lock up
>> without any particular error message.
>>
>> This patch fixes the regression on r8a7779 by moving the TWD
>> registration code from smp_init_cpus() to sys_timer->init() time.
>>
>> Signed-off-by: Magnus Damm <damm@opensource.se>
>
> I'm a bit confused here. Does sh73a0 work OK? If so, why is the behavior
> any different?

It doesn't,both are busted I'm afraid. But I fixed the r8a7779 one
myself and let Morimoto-san deal with sh73a0 to make sure it got fixed
and tested too.

Cheers,

/ magnus

Re: [PATCH] mach-shmobile: r8a7779 SMP TWD boot regression fix

[Marc Zyngier]

On 10/05/12 11:10, Magnus Damm wrote:
> On Thu, May 10, 2012 at 7:03 PM, Marc Zyngier <marc.zyngier@arm.com> wrote:
>> Hi Magnus,
>>
>> On 10/05/12 06:57, Magnus Damm wrote:
>>> From: Magnus Damm <damm@opensource.se>
>>>
>>> Fix SMP TWD boot regression on r8a7779 based platforms caused by:
>>>
>>> 4200b16 ARM: shmobile: convert to twd_local_timer_register() interface
>>>
>>> After the merge of the above commit it has been impossible to boot
>>> r8a7779 based SoCs with SMP enabled and CONFIG_HAVE_ARM_TWD=y. The
>>> kernel crashes at smp_init_cpus() timing which is before the console
>>> has been initialized, so to the user this looks like a kernel lock up
>>> without any particular error message.
>>>
>>> This patch fixes the regression on r8a7779 by moving the TWD
>>> registration code from smp_init_cpus() to sys_timer->init() time.
>>>
>>> Signed-off-by: Magnus Damm <damm@opensource.se>
>>
>> I'm a bit confused here. Does sh73a0 work OK? If so, why is the behavior
>> any different?
> 
> It doesn't,both are busted I'm afraid. But I fixed the r8a7779 one
> myself and let Morimoto-san deal with sh73a0 to make sure it got fixed
> and tested too.

OK. It would be good to fold these two patches into one, then.

FWIW, Acked-by: Marc Zyngier <marc.zyngier@arm.com>

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

Re: [PATCH] mach-shmobile: r8a7779 SMP TWD boot regression fix

[Magnus Damm]

On Thu, May 10, 2012 at 7:13 PM, Marc Zyngier <marc.zyngier@arm.com> wrote:
> On 10/05/12 11:10, Magnus Damm wrote:
>> On Thu, May 10, 2012 at 7:03 PM, Marc Zyngier <marc.zyngier@arm.com> wrote:
>>> Hi Magnus,
>>>
>>> On 10/05/12 06:57, Magnus Damm wrote:
>>>> From: Magnus Damm <damm@opensource.se>
>>>>
>>>> Fix SMP TWD boot regression on r8a7779 based platforms caused by:
>>>>
>>>> 4200b16 ARM: shmobile: convert to twd_local_timer_register() interface
>>>>
>>>> After the merge of the above commit it has been impossible to boot
>>>> r8a7779 based SoCs with SMP enabled and CONFIG_HAVE_ARM_TWD=y. The
>>>> kernel crashes at smp_init_cpus() timing which is before the console
>>>> has been initialized, so to the user this looks like a kernel lock up
>>>> without any particular error message.
>>>>
>>>> This patch fixes the regression on r8a7779 by moving the TWD
>>>> registration code from smp_init_cpus() to sys_timer->init() time.
>>>>
>>>> Signed-off-by: Magnus Damm <damm@opensource.se>
>>>
>>> I'm a bit confused here. Does sh73a0 work OK? If so, why is the behavior
>>> any different?
>>
>> It doesn't,both are busted I'm afraid. But I fixed the r8a7779 one
>> myself and let Morimoto-san deal with sh73a0 to make sure it got fixed
>> and tested too.
>
> OK. It would be good to fold these two patches into one, then.
>
> FWIW, Acked-by: Marc Zyngier <marc.zyngier@arm.com>

Thanks! I intentionally made them broken out since they fixed
different platforms, but that's not so important to me.

/ magnus

Re: [PATCH] mach-shmobile: r8a7779 SMP TWD boot regression fix

[Rafael J. Wysocki]

On Thursday, May 10, 2012, Magnus Damm wrote:
> On Thu, May 10, 2012 at 7:13 PM, Marc Zyngier <marc.zyngier@arm.com> wrote:
> > On 10/05/12 11:10, Magnus Damm wrote:
> >> On Thu, May 10, 2012 at 7:03 PM, Marc Zyngier <marc.zyngier@arm.com> wrote:
> >>> Hi Magnus,
> >>>
> >>> On 10/05/12 06:57, Magnus Damm wrote:
> >>>> From: Magnus Damm <damm@opensource.se>
> >>>>
> >>>> Fix SMP TWD boot regression on r8a7779 based platforms caused by:
> >>>>
> >>>> 4200b16 ARM: shmobile: convert to twd_local_timer_register() interface
> >>>>
> >>>> After the merge of the above commit it has been impossible to boot
> >>>> r8a7779 based SoCs with SMP enabled and CONFIG_HAVE_ARM_TWD=y. The
> >>>> kernel crashes at smp_init_cpus() timing which is before the console
> >>>> has been initialized, so to the user this looks like a kernel lock up
> >>>> without any particular error message.
> >>>>
> >>>> This patch fixes the regression on r8a7779 by moving the TWD
> >>>> registration code from smp_init_cpus() to sys_timer->init() time.
> >>>>
> >>>> Signed-off-by: Magnus Damm <damm@opensource.se>
> >>>
> >>> I'm a bit confused here. Does sh73a0 work OK? If so, why is the behavior
> >>> any different?
> >>
> >> It doesn't,both are busted I'm afraid. But I fixed the r8a7779 one
> >> myself and let Morimoto-san deal with sh73a0 to make sure it got fixed
> >> and tested too.
> >
> > OK. It would be good to fold these two patches into one, then.
> >
> > FWIW, Acked-by: Marc Zyngier <marc.zyngier@arm.com>
> 
> Thanks! I intentionally made them broken out since they fixed
> different platforms, but that's not so important to me.

Applied.

Thanks,
Rafael