Re: [PATCH V13 0/5] Generate device tree node for pci devices

Herve Codina
2023-09-15T17:31:48Z

Hi Andy,

On Wed, 13 Sep 2023 14:17:30 +0300
Andy Shevchenko <andriy.shevchenko@intel.com> wrote:

> On Tue, Sep 12, 2023 at 02:12:04PM -0500, Rob Herring wrote:
> > On Mon, Sep 11, 2023 at 3:37 PM Andy Shevchenko
> > <andriy.shevchenko@intel.com> wrote:
> > > On Tue, Aug 15, 2023 at 10:19:55AM -0700, Lizhi Hou wrote:
>
> ...
>
> > > Can you point out to the ACPI excerpt(s) of the description of anything related
> > > to the device(s) in question?
> >
> > I don't understand what you are asking for.
>
> Through the email thread it was mentioned that this series was tested on the
> ACPI enabled platform, Jonathan (IIRC) asked why do we need to have a shadow
> DT for the something that ACPI already describes. That's why I'm trying to
> understand if it's the case. and if so, how can we improve the approach.
>

Patches from Frank Rowand series [1] are needed to create an of_root_node if a DT
was not provided by the firmware, bootloader, etc that run the kernel.

[1]: https://lore.kernel.org/lkml/20220624034327.2542112-1-frowand.list@gmail.com/

Current Lizhi's series creates nodes from the PCI host node during the PCI
enumeration. It creates PCI-PCI bridge and PCI device nodes.

I use these series on an ACPI system.

I need one more missing component: the node related to the PCI host bridge
This was the purpose of Clement's work. This work was not sent upstream yet and I
am working on it in order to have a full tree from the of_root to the PCI device
ie:
of_root <-- Frank Rowand series
+ of_host_pci_bridge <-- Clement's work
+ pci_bridge <-- Current Lizhi series
+ pci_bridge <-- Current Lizhi series
...
+ pci_dev <-- Current Lizhi series

Hope that this status helped.

Regards,
Hervé

--
Hervé Codina, Bootlin
Embedded Linux and Kernel engineering