[U-Boot] [PATCH v3 02/15] sysreset-uclass: ensure udevice is probed before requesting reset

Álvaro Fernández Rojas
2017-04-19T09:18:39Z

This is what I think it's going on:
sysreset_walk():
- calls uclass_first_device():
- Calls uclass_find_first_device():
- device is found.
- ret is set to 0.
- Calls uclass_get_device_tail():
- ret == 0 -> doesn't return.
- dev != null -> assert is true.
- Calls device_probe():
- It fails *somewhere* and goes to fail WITHOUT setting dev to NULL.
- ret != 0 -> returns without setting devp = dev.
- dev is NOT NULL but device is not probed.
- Tries to get ops from a not probed device -> Exception.
So basically it's a bug related to device_probe not nulling dev when failing and sysreset_walk() checking only if the device is not null and not the actual return of uclass_first_device() and uclass_next_device()...

On Wed, Apr 19, 2017 at 7:28 AM +0200, "Álvaro Fernández Rojas" <noltari@gmail.com> wrote:

Hi Simon,

El 19/04/2017 a las 2:13, Simon Glass escribió:
> Hi Alvaro,
>
> On 18 April 2017 at 14:38, Álvaro Fernández Rojas wrote:
>> This causes exceptions for drivers that aren't probed when reboot is
>> requested.
>>
>> Signed-off-by: Álvaro Fernández Rojas
>> ---
>> v3: add new patch to ensure that the device is probed
>>
>> drivers/sysreset/sysreset-uclass.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/sysreset/sysreset-uclass.c b/drivers/sysreset/sysreset-uclass.c
>> index 3566d17..329dc2e 100644
>> --- a/drivers/sysreset/sysreset-uclass.c
>> +++ b/drivers/sysreset/sysreset-uclass.c
>> @@ -34,6 +34,9 @@ int sysreset_walk(enum sysreset_t type)
>> for (uclass_first_device(UCLASS_SYSRESET, &dev);
>> dev;
>> uclass_next_device(&dev)) {
>> + if (!device_active(dev) && device_probe(dev))
>> + continue;
>
> uclass_first_device() should activate the device. Can you please dig
> into what is going on here?
I'll try to investigate it later today or tomorrow...
Could this be related to core/uclass: uclass_get_device_tail: always set devp?
http://patchwork.ozlabs.org/patch/751929/

>
>> +
>> ret = sysreset_request(dev, type);
>> if (ret == -EINPROGRESS)
>> break;
>> --
>> 2.1.4
>>
>
> Regards,
> Simon
>
Regards,
Álvaro.