[U-Boot] [PATCH] pci: Support parsing PCI controller DT subnodes

[Marek Vasut]

On 08/08/2018 05:32 PM, Bin Meng wrote:
> Hi Marek,
> 
> On Wed, Aug 8, 2018 at 10:33 PM, Marek Vasut <marek.vasut at gmail.com> wrote:
>> On 08/08/2018 03:39 PM, Bin Meng wrote:
>>> Hi Marek,
>>>
>>> On Wed, Aug 8, 2018 at 9:24 PM, Marek Vasut <marek.vasut at gmail.com> wrote:
>>>> On 08/08/2018 03:14 PM, Bin Meng wrote:
>>>>> Hi Marek,
>>>>>
>>>>> On Wed, Aug 8, 2018 at 9:03 PM, Marek Vasut <marek.vasut at gmail.com> wrote:
>>>>>> The PCI controller can have DT subnodes describing extra properties
>>>>>> of particular PCI devices, ie. a PHY attached to an EHCI controller
>>>>>> on a PCI bus. This patch parses those DT subnodes and assigns a node
>>>>>> to the PCI device instance, so that the driver can extract details
>>>>>> from that node and ie. configure the PHY using the PHY subsystem.
>>>>>>
>>>>>> Signed-off-by: Marek Vasut <marek.vasut+renesas at gmail.com>
>>>>>> Cc: Simon Glass <sjg at chromium.org>
>>>>>> ---
>>>>>>  drivers/pci/pci-uclass.c | 14 ++++++++++++++
>>>>>>  1 file changed, 14 insertions(+)
>>>>>>
>>>>>> diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
>>>>>> index 46e9c71bdf..306bea0dbf 100644
>>>>>> --- a/drivers/pci/pci-uclass.c
>>>>>> +++ b/drivers/pci/pci-uclass.c
>>>>>> @@ -662,6 +662,8 @@ static int pci_find_and_bind_driver(struct udevice *parent,
>>>>>>                 for (id = entry->match;
>>>>>>                      id->vendor || id->subvendor || id->class_mask;
>>>>>>                      id++) {
>>>>>> +                       ofnode node;
>>>>>> +
>>>>>>                         if (!pci_match_one_id(id, find_id))
>>>>>>                                 continue;
>>>>>>
>>>>>> @@ -691,6 +693,18 @@ static int pci_find_and_bind_driver(struct udevice *parent,
>>>>>>                                 goto error;
>>>>>>                         debug("%s: Match found: %s\n", __func__, drv->name);
>>>>>>                         dev->driver_data = find_id->driver_data;
>>>>>> +
>>>>>> +                       dev_for_each_subnode(node, parent) {
>>>>>> +                               phys_addr_t df, size;
>>>>>> +                               df = ofnode_get_addr_size(node, "reg", &size);
>>>>>> +
>>>>>> +                               if (PCI_FUNC(df) == PCI_FUNC(bdf) &&
>>>>>> +                                   PCI_DEV(df) == PCI_DEV(bdf)) {
>>>>>> +                                       dev->node = node;
>>>>>> +                                       break;
>>>>>> +                               }
>>>>>
>>>>> The function pci_find_and_bind_driver() is supposed to bind devices
>>>>> that are NOT in the device tree. Adding device tree access in this
>>>>> routine is quite odd. You can add the EHCI controller that need such
>>>>> PHY subnodes in the device tree and there is no need to modify
>>>>> anything I believe. If you are looking for an example, please check
>>>>> pciuart0 in arch/x86/dts/crownbay.dts.
>>>>
>>>> Well this does not work for me, the EHCI PCI doesn't get a DT node
>>>> assigned, check r8a7794.dtsi for the PCI devices I use.
>>>>
>>>
>>> I think that's because you don't specify a "compatible" string for
>>> these two EHCI PCI nodes.
>>
>> That's perfectly fine, why should I specify it ? Linux has no problem
>> with it either.
>>
> 
> Without a "compatible" string, DM does not bind any device in the
> device tree to a driver, hence no device node created. This is not
> Linux.

DT is NOT Linux specific, it is OS-agnostic, DT describes hardware and
hardware only. If U-Boot cannot parse DT correctly, U-Boot is broken and
must be fixed.

This is a fix. If there is a better fix, I am open to it.

-- 
Best regards,
Marek Vasut