[U-Boot] [EXT] Re: [PATCH 1/3] arm64: mvebu: Trigger PCI devices scan at early init stage

[Simon Glass]

Hi,

On 2 April 2017 at 05:50, Konstantin Porotchkin <kostap at marvell.com> wrote:
> Hi, Simon,
>
> On 04/01/2017 07:23 AM, Simon Glass wrote:
>>
>> External Email
>>
>> ----------------------------------------------------------------------
>>
>> Hi Konstanitin,
>>
>> On 30 March 2017 at 07:58, Konstantin Porotchkin <kostap at marvell.com>
>> wrote:
>>>
>>>
>>>
>>> On 03/30/2017 04:31 PM, Stefan Roese wrote:
>>>>
>>>>
>>>> (adding Simon to Cc for PCI related question)
>>>>
>>>> On 28.03.2017 17:36, kostap at marvell.com wrote:
>>>>>
>>>>>
>>>>> From: Konstantin Porotchkin <kostap at marvell.com>
>>>>>
>>>>> Add PCIe initialization at early init stage.
>>>>> This operation has a side effect of detecting all PCIe
>>>>> plug-in cards, so the operator is not obligated to issue
>>>>> "pci enum" command though CLI for this purpose.
>>>>
>>>>
>>>>
>>>> I'm not sure, if this should be handled this way. Simon, how
>>>> is such a default PCI scan with DM supposed to get done? Is
>>>> there a way do do this automatically without the need that
>>>> the user has to issue "pci enum" manually?
>>>
>>>
>>> I was not sure either, but did not see any other way of doing so.
>>> I asked to add this change by our Robot/Jenkins automation test team.
>>
>>
>> It seems reasonable. We actually have some platforms that require PCI
>> buses to be probed before we know what devices are in the system, and
>> some of these are important.
>>
>> For example, if your network controller is on PCI then U-Boot will not
>> know about it (unless you have it in the device tree) until PCI is
>> probed.
>>
>> I am wondering whether we should add a uclass flag that indicates that
>> uclass members should be automatically probed on start-up?
>>
>> It would not be set for SATA, but would be for PCI.
>
> Thank you for your explanation.
> So, as the bottom line - Can I leave the PCIe init call in place and remove
> the SATA devices walk through from this patch?
> In my case the PCIe devices should be initialized for detection of a network
> card.
>

I think we should add a new DM_UC_FLAG_AUTO_PROBE to uclass.h which
causes U-Boot to probe all devices in that uclass. This code could be
added to dm_init_and_scan(). You could set the flag for PCI. Do you
want to work up a patch for that?

This is your board code so I don't have a strong opinion on exactly
what you do here - but I'd prefer to figure out a generic solution.

> Thanks
> Kosta
>
>>
>>>>
>>>>
>>>>> Also convert the SATA first device scan to a walk through
>>>>> all availabel SATA devices.
>>>>
>>>>
>>>>
>>>> This should be done in a separate patch. But seeing this,
>>>> won't this SATA / AHCI code be gone completely from this
>>>> file, once this is converted into a "real" DM AHCI / SCSI
>>>> driver (please look at my preliminary patch for this).
>>>
>>>
>>> Will check your patch, thank you.
>>> Maybe this change has to be completely removed if Simon guide me to the
>>> right solution for automatic PCIe enumeration.
>>>
>>
>> Regards,
>> Simon
>>

Regards,
Simon