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[PATCH] ARM: sa1100: Initialize gpio after gpio subsystem has been initialized

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  [PATCH] ARM: sa1100: Initialize gpio after gpio subsystem has been initialized Guenter Roeck <linux@roeck-us.net> - 2016-03-29 20:20 +0200
    Re: [PATCH] ARM: sa1100: Initialize gpio after gpio subsystem has  been initialized Guenter Roeck <linux@roeck-us.net> - 2016-03-31 18:30 +0200
      Re: [PATCH] ARM: sa1100: Initialize gpio after gpio subsystem has  been initialized Linus Walleij <linus.walleij@linaro.org> - 2016-04-01 10:10 +0200
        Re: [PATCH] ARM: sa1100: Initialize gpio after gpio subsystem has  been initialized Guenter Roeck <linux@roeck-us.net> - 2016-04-01 16:10 +0200

#1366526 — [PATCH] ARM: sa1100: Initialize gpio after gpio subsystem has been initialized

The sa1100 gpio driver was initialized from interrupt initialization code,
which is earlier than the gpio subsystem is initialized. Since commit
ff2b13592299 ("gpio: make the gpiochip a real device"), this is fatal
and causes the system to crash.

The sa1100 gpio driver must be initialized prior to arch_initcall, since
its gpio pins are used in arch_initcall code, but after the gpio subsystem
is initialized (core_initcall). Initialize it with postcore_initcall.

Fixes: ff2b13592299 ("gpio: make the gpiochip a real device")
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---

Tested by building collie_defconfig and:

qemu-system-arm -M collie -kernel arch/arm/boot/zImage \
	-no-reboot -initrd busybox-armv4.cpio \
	--append "rdinit=/sbin/init console=ttySA1" -monitor null -nographic

 arch/arm/mach-sa1100/generic.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-sa1100/generic.c b/arch/arm/mach-sa1100/generic.c
index 345e63f4eb71..850aa7f8f649 100644
--- a/arch/arm/mach-sa1100/generic.c
+++ b/arch/arm/mach-sa1100/generic.c
@@ -321,6 +321,15 @@ static int __init sa1100_init(void)
 
 arch_initcall(sa1100_init);
 
+static int __init sa1100_gpio_init(void)
+{
+	sa1100_init_gpio();
+
+	return 0;
+}
+
+postcore_initcall(sa1100_gpio_init);
+
 void __init sa11x0_init_late(void)
 {
 	sa11x0_pm_init();
@@ -386,8 +395,6 @@ void __init sa1100_init_irq(void)
 	request_resource(&iomem_resource, &irq_resource);
 
 	sa11x0_init_irq_nodt(IRQ_GPIO0_SC, irq_resource.start);
-
-	sa1100_init_gpio();
 }
 
 /*
-- 
2.5.0

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#1368432 — Re: [PATCH] ARM: sa1100: Initialize gpio after gpio subsystem has been initialized

On Tue, Mar 29, 2016 at 11:15:49AM -0700, Guenter Roeck wrote:
> The sa1100 gpio driver was initialized from interrupt initialization code,
> which is earlier than the gpio subsystem is initialized. Since commit
> ff2b13592299 ("gpio: make the gpiochip a real device"), this is fatal
> and causes the system to crash.
> 
> The sa1100 gpio driver must be initialized prior to arch_initcall, since
> its gpio pins are used in arch_initcall code, but after the gpio subsystem
> is initialized (core_initcall). Initialize it with postcore_initcall.
> 
> Fixes: ff2b13592299 ("gpio: make the gpiochip a real device")
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Please ignore/drop this patch - a better (cleaner) fix is in the works
for gpiolib.

Thanks,
Guenter

> ---
> 
> Tested by building collie_defconfig and:
> 
> qemu-system-arm -M collie -kernel arch/arm/boot/zImage \
> 	-no-reboot -initrd busybox-armv4.cpio \
> 	--append "rdinit=/sbin/init console=ttySA1" -monitor null -nographic
> 
>  arch/arm/mach-sa1100/generic.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mach-sa1100/generic.c b/arch/arm/mach-sa1100/generic.c
> index 345e63f4eb71..850aa7f8f649 100644
> --- a/arch/arm/mach-sa1100/generic.c
> +++ b/arch/arm/mach-sa1100/generic.c
> @@ -321,6 +321,15 @@ static int __init sa1100_init(void)
>  
>  arch_initcall(sa1100_init);
>  
> +static int __init sa1100_gpio_init(void)
> +{
> +	sa1100_init_gpio();
> +
> +	return 0;
> +}
> +
> +postcore_initcall(sa1100_gpio_init);
> +
>  void __init sa11x0_init_late(void)
>  {
>  	sa11x0_pm_init();
> @@ -386,8 +395,6 @@ void __init sa1100_init_irq(void)
>  	request_resource(&iomem_resource, &irq_resource);
>  
>  	sa11x0_init_irq_nodt(IRQ_GPIO0_SC, irq_resource.start);
> -
> -	sa1100_init_gpio();
>  }
>  
>  /*
> -- 
> 2.5.0
> 

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#1369085 — Re: [PATCH] ARM: sa1100: Initialize gpio after gpio subsystem has been initialized

On Thu, Mar 31, 2016 at 6:21 PM, Guenter Roeck <linux@roeck-us.net> wrote:
> On Tue, Mar 29, 2016 at 11:15:49AM -0700, Guenter Roeck wrote:
>> The sa1100 gpio driver was initialized from interrupt initialization code,
>> which is earlier than the gpio subsystem is initialized. Since commit
>> ff2b13592299 ("gpio: make the gpiochip a real device"), this is fatal
>> and causes the system to crash.
>>
>> The sa1100 gpio driver must be initialized prior to arch_initcall, since
>> its gpio pins are used in arch_initcall code, but after the gpio subsystem
>> is initialized (core_initcall). Initialize it with postcore_initcall.
>>
>> Fixes: ff2b13592299 ("gpio: make the gpiochip a real device")
>> Cc: Linus Walleij <linus.walleij@linaro.org>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>
> Please ignore/drop this patch - a better (cleaner) fix is in the works
> for gpiolib.

This delivers though. I tested it on my also regressing iPAQ.

Yours,
Linus Walleij

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#1369336 — Re: [PATCH] ARM: sa1100: Initialize gpio after gpio subsystem has been initialized

On Fri, Apr 01, 2016 at 10:04:57AM +0200, Linus Walleij wrote:
> On Thu, Mar 31, 2016 at 6:21 PM, Guenter Roeck <linux@roeck-us.net> wrote:
> > On Tue, Mar 29, 2016 at 11:15:49AM -0700, Guenter Roeck wrote:
> >> The sa1100 gpio driver was initialized from interrupt initialization code,
> >> which is earlier than the gpio subsystem is initialized. Since commit
> >> ff2b13592299 ("gpio: make the gpiochip a real device"), this is fatal
> >> and causes the system to crash.
> >>
> >> The sa1100 gpio driver must be initialized prior to arch_initcall, since
> >> its gpio pins are used in arch_initcall code, but after the gpio subsystem
> >> is initialized (core_initcall). Initialize it with postcore_initcall.
> >>
> >> Fixes: ff2b13592299 ("gpio: make the gpiochip a real device")
> >> Cc: Linus Walleij <linus.walleij@linaro.org>
> >> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> >
> > Please ignore/drop this patch - a better (cleaner) fix is in the works
> > for gpiolib.
> 
> This delivers though. I tested it on my also regressing iPAQ.
> 
I am a bit concerned that the gpio initialization was that early on purpose,
and that by moving it we might miss some use cases. I did not find any, but that
doesn't mean that there are none. Without knowing _why_ the initialization was
that early, I would prefer not to touch the code if it can be avoided.

Thanks,
Guenter

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