diff mbox

pxa_defconfig runtime failures due to 'ARM: pxa: activate pinctrl for device-tree machines'

Message ID 87a8jah9ok.fsf@belgarion.home (mailing list archive)
State New, archived
Headers show

Commit Message

Robert Jarzmik May 28, 2016, 8:24 a.m. UTC
Guenter Roeck <linux@roeck-us.net> writes:

> Hi,
>
> your mainline commit f806dac5938b ("ARM: pxa: activate pinctrl for device-tree
> machines") causes various non-devicetree systems to fail with the following
> error messages when running a pxa_defconfig image.
Ah yes, you're right.

>
> During boot:
>
> Can't request reset_gpio
>
> At reboot:
>
> reboot: Restarting system
> ------------[ cut here ]------------
> kernel BUG at arch/arm/mach-pxa/reset.c:59!
> ...
>
> Added logging shows that the error seen when trying to request the reset gpio
> is -EPROBE_DEFER, and that the pxa gpio driver is not instantiated.
>
> This is seen when attempting to run akita, borzoi, spitz, terrier, or tosa
> in qemu with pxa_defconfig. Reverting your patch fixes the problem.
>
> Is this on purpose ?
Well no :)
The real reason behind is that gpio handling for pxa in its current state cannot
be built for _both_ a devicetree machine (ie. pxa-dt.c) and a non devicetree
machine (ie. corgi, tosa, ...).

This is turn is because for devicetree a pinctrl is enforced for the machine,
and a pinctrl driver is required. If it's not available, pxa_gpio_request()
fails on pinctrl_request_gpio() and returns -EPROBE_DEFER.

Now the true chicken and egg problem is than machine files,
ie. arch/arm/mach-pxa/xxx.c are using gpio before the drivers are probed, in the
init_machine() function, and that's why pinctrl/gpio for legacy machine files is
a bit difficult.

> Unless I am missing something, it effectively means that
> pxa_defconfig no longer works for pxa3xx systems, since those do not support
> devicetree (or at least there is no devicetree file which includes
> pxa3xx.dtsi).
I'd rather say that pxa_defconfig doesn't work anymore on any legacy system.
Its first purpose was to ensure compilation coverage of all legacy pxa systems.
Its second one was to have a single kernel bootable on all legacy pxa systems.

Therefore, would you tell me if the patch in [1] fixes your issue ?

Cheers.

Comments

Guenter Roeck May 28, 2016, 9:17 p.m. UTC | #1
On 05/28/2016 01:24 AM, Robert Jarzmik wrote:
> Guenter Roeck <linux@roeck-us.net> writes:
>
>> Hi,
>>
>> your mainline commit f806dac5938b ("ARM: pxa: activate pinctrl for device-tree
>> machines") causes various non-devicetree systems to fail with the following
>> error messages when running a pxa_defconfig image.
> Ah yes, you're right.
>
>>
>> During boot:
>>
>> Can't request reset_gpio
>>
>> At reboot:
>>
>> reboot: Restarting system
>> ------------[ cut here ]------------
>> kernel BUG at arch/arm/mach-pxa/reset.c:59!
>> ...
>>
>> Added logging shows that the error seen when trying to request the reset gpio
>> is -EPROBE_DEFER, and that the pxa gpio driver is not instantiated.
>>
>> This is seen when attempting to run akita, borzoi, spitz, terrier, or tosa
>> in qemu with pxa_defconfig. Reverting your patch fixes the problem.
>>
>> Is this on purpose ?
> Well no :)
> The real reason behind is that gpio handling for pxa in its current state cannot
> be built for _both_ a devicetree machine (ie. pxa-dt.c) and a non devicetree
> machine (ie. corgi, tosa, ...).
>
> This is turn is because for devicetree a pinctrl is enforced for the machine,
> and a pinctrl driver is required. If it's not available, pxa_gpio_request()
> fails on pinctrl_request_gpio() and returns -EPROBE_DEFER.
>
> Now the true chicken and egg problem is than machine files,
> ie. arch/arm/mach-pxa/xxx.c are using gpio before the drivers are probed, in the
> init_machine() function, and that's why pinctrl/gpio for legacy machine files is
> a bit difficult.
>
>> Unless I am missing something, it effectively means that
>> pxa_defconfig no longer works for pxa3xx systems, since those do not support
>> devicetree (or at least there is no devicetree file which includes
>> pxa3xx.dtsi).
> I'd rather say that pxa_defconfig doesn't work anymore on any legacy system.
> Its first purpose was to ensure compilation coverage of all legacy pxa systems.
> Its second one was to have a single kernel bootable on all legacy pxa systems.
>
> Therefore, would you tell me if the patch in [1] fixes your issue ?
>

Yes, it does. It is actually the workaround I deployed for my test builds,
since I thought that the change was on purpose.

Thanks,
Guenter
Robert Jarzmik May 31, 2016, 6:27 a.m. UTC | #2
Guenter Roeck <linux@roeck-us.net> writes:

> On 05/28/2016 01:24 AM, Robert Jarzmik wrote:
>> Guenter Roeck <linux@roeck-us.net> writes:
>>
>>> Hi,
>> I'd rather say that pxa_defconfig doesn't work anymore on any legacy system.
>> Its first purpose was to ensure compilation coverage of all legacy pxa systems.
>> Its second one was to have a single kernel bootable on all legacy pxa systems.
>>
>> Therefore, would you tell me if the patch in [1] fixes your issue ?
>>
>
> Yes, it does. It is actually the workaround I deployed for my test builds,
> since I thought that the change was on purpose.

Good. Can I take that as a Tested-by ?

Cheers.
Guenter Roeck May 31, 2016, 2:53 p.m. UTC | #3
On 05/30/2016 11:27 PM, Robert Jarzmik wrote:
> Guenter Roeck <linux@roeck-us.net> writes:
>
>> On 05/28/2016 01:24 AM, Robert Jarzmik wrote:
>>> Guenter Roeck <linux@roeck-us.net> writes:
>>>
>>>> Hi,
>>> I'd rather say that pxa_defconfig doesn't work anymore on any legacy system.
>>> Its first purpose was to ensure compilation coverage of all legacy pxa systems.
>>> Its second one was to have a single kernel bootable on all legacy pxa systems.
>>>
>>> Therefore, would you tell me if the patch in [1] fixes your issue ?
>>>
>>
>> Yes, it does. It is actually the workaround I deployed for my test builds,
>> since I thought that the change was on purpose.
>
> Good. Can I take that as a Tested-by ?
>
Yes.

Guenter
diff mbox

Patch

diff --git a/arch/arm/configs/pxa_defconfig b/arch/arm/configs/pxa_defconfig
index dc5517eaf09f..a016ecc0084b 100644
--- a/arch/arm/configs/pxa_defconfig
+++ b/arch/arm/configs/pxa_defconfig
@@ -26,8 +26,6 @@  CONFIG_PARTITION_ADVANCED=y
 CONFIG_LDM_PARTITION=y
 CONFIG_CMDLINE_PARTITION=y
 CONFIG_ARCH_PXA=y
-CONFIG_MACH_PXA27X_DT=y
-CONFIG_MACH_PXA3XX_DT=y
 CONFIG_ARCH_LUBBOCK=y
 CONFIG_MACH_MAINSTONE=y
 CONFIG_MACH_ZYLONITE300=y