[U-Boot] [PATCH V2 1/2] pci: Support parsing PCI controller DT subnodes

[Marek Vasut]

On 09/26/2018 07:42 AM, Simon Glass wrote:
> Hi Marek,
> 
> On 20 September 2018 at 17:56, Marek Vasut <marek.vasut at gmail.com> wrote:
>> On 09/20/2018 03:47 AM, Bin Meng wrote:
>> [...]
>>
>>>>>>>>> I suspect the best answer is to move the emulator so it is a direct
>>>>>>>>> child of the bus. You would need to update sandbox_pci_get_emul() to
>>>>>>>>> call device_find_first_child() on 'bus' instead of 'dev'.
>>>>>>>>
>>>>>>>> Sounds to me _way_ out of scope for this patchset.
>>>>>>>
>>>>>>> Dynamic binding is already supported on Sandbox. I guess Simon may
>>>>>>> have missed the part.
>>>>>>
>>>>>> Well, where is an example of that ? Because I am not seeing one.
>>>>>>
>>>>>
>>>>> I already pointed out in the previous email. In
>>>>> arch/sandbox/dts/test.dts, the 2nd PCI controller has two swap_case
>>>>> devices and the 3rd controller has one.
>>>>
>>>> By "second" you mean pci1: or pci2: ? Because pci1: is second , after
>>>> pci0 . It'd really help if you were clearer in what you refer to.
>>>>
>>>
>>> It's pci1. You can see there is no subnode under pci1 there yet if you
>>> type 'pci 1' from the U-Boot shell you see two PCI devices.
>>
>> I'd really appreciate it if you could be more precise when referring to
>> things.
>>
>>>>> In swap_case.c, U_BOOT_PCI_DEVICE() is there which is also a clear
>>>>> sign that the driver supports dynamic binding. Of course, the driver
>>>>> supports "compatible" too as you noticed.
>>>>
>>>> Are you talking about sandbox,dev-info DT property here ?
>>>
>>> This is the property Sandbox uses to make the dynamic binding work.
>>> You can bypass this.
>>
>> Why would I want to bypass this ?
>>
>>> The key here is that swap_case driver supports
>>> both "compatible" and dynamic binding, so you can write test cases to
>>> cover this newly added ofnode scenario.
>>
>> That's great, and after spending even more time on this (probably days
>> by now), I just keep finding more and more limitations of the virtual
>> PCI subsystem which makes writing this testcase really hard. And none of
>> that really helps fixing the real problem on my real hardware, which
>> really stays broken.
> 
> You could fix that with a 5-minute patch to add a compatible string :-)

No, that's a hack.

> The problem is that you want to do it a certain way. Yes the test
> system has limitations but it is better than what we had before (no
> tests). We should expand its capability as we add new functionality.
> 
> Regards,
> Simon
> 


-- 
Best regards,
Marek Vasut