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

Bin Meng
2018-08-08T15:32:44Z

Hi Marek,

On Wed, Aug 8, 2018 at 10:33 PM, Marek Vasut <marek.vasut@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@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@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@gmail.com>
>>>>> Cc: Simon Glass <sjg@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.

Regards,
Bin