Re: [PATCH -next] xtensa: Fix build error due to missing include file

[Guenter Roeck <linux@roeck-us.net>]

On 07/24/2016 08:18 AM, Rob Herring wrote:
> On Sun, Jul 24, 2016 at 9:20 AM, Max Filippov <jcmvbkbc@gmail.com> wrote:
>> On Sun, Jul 24, 2016 at 9:00 AM, Guenter Roeck <linux@roeck-us.net> wrote:
>>> On 07/23/2016 05:45 PM, Max Filippov wrote:
>>>>
>>>> On Sun, Jul 24, 2016 at 3:24 AM, Guenter Roeck <linux@roeck-us.net> wrote:
>>>>>
>>>>> Commit 69d99e6c0d621f ("xtensa: Remove unnecessary of_platform_populate
>>>>> with default match table") dropped various include files from
>>>>> arch/xtensa/kernel/setup.c. This results in the following build error.
>>>>>
>>>>> arch/xtensa/kernel/setup.c: In function ‘xtensa_dt_io_area’:
>>>>> arch/xtensa/kernel/setup.c:213:2: error:
>>>>>           implicit declaration of function ‘of_read_ulong’
>>>>>
>>>>> Fixes: 69d99e6c0d621f ("xtensa: Remove unnecessary of_platform_populate
>>>>> with default match table")
>>>>> Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
>>>>> Cc: Rob Herring <robh@kernel.org>
>>>>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>>>>> ---
>>>>> I would suggest to merge this patch into the commit causing the problem
>>>>> if possible.
>>>>>
>>>>>    arch/xtensa/kernel/setup.c | 1 +
>>>>>    1 file changed, 1 insertion(+)
>>>>
>>>>
>>>> Acked-by: Max Filippov <jcmvbkbc@gmail.com>
>>>>
>>>
>>> Heads up: xtensa images build after this patch, but the image that
>>> previously failed to build (generic_kc705_defconfig) doesn't boot,
>>> at least not with qemu. I don't know if this is caused by 69d99e6c0d621f
>>> or by some other patch.
>>
>> It seems to be booting, but serial console is non-functional.
>> With commit 69d99e6c0d621f ("xtensa: Remove unnecessary of_platform_populate
>> with default match table") I see the following message during boot:
>>
>> [    6.375284] of_serial fd050020.serial: clk or clock-frequency not defined
>>
>> Reverting that commit fixes serial console for me.
>> Any suggestions on what might go wrong?
>
> Probably the init order changed somehow and deferred probe is not
> supported correctly.
>

While the message is due to -EPROBE_DEFER (and there should really be no message
in this case), I suspect that the underlying problem is that of_clk_init() is
now called way too early, before the clock source is fully initialized.
Specifically, the call now happens before the message "clocksource: Switched
to clocksource ccount", which at least looks suspicious.

If I move of_clk_init() back into xtensa_device_probe(), to be called as
device_initcall(), everything is fine.

Guenter