Re: [RFC PATCH 02/21] dt-bindings: PCI: Endpoint: Add DT bindings for PCI EPF Device
From: Rob Herring
Date: Tue Oct 15 2019 - 14:42:49 EST
On Thu, Sep 26, 2019 at 04:59:14PM +0530, Kishon Vijay Abraham I wrote:
> Add device tree bindings for PCI endpoint function device. The
> nodes for PCI endpoint function device should be attached to
> PCI endpoint function bus.
>
> Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
> ---
> .../bindings/pci/endpoint/pci-epf.txt | 28 +++++++++++++++++++
> 1 file changed, 28 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/pci/endpoint/pci-epf.txt
This and the previous patch for the bus should be combined and please
convert to a schema.
>
> diff --git a/Documentation/devicetree/bindings/pci/endpoint/pci-epf.txt b/Documentation/devicetree/bindings/pci/endpoint/pci-epf.txt
> new file mode 100644
> index 000000000000..f006395fd526
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pci/endpoint/pci-epf.txt
> @@ -0,0 +1,28 @@
> +PCI Endpoint Function Device
> +
> +This describes the generic bindings to be used when a device has to be
> +exposed to the remote host over PCIe. The device could be an actual
> +peripheral in the platform or a virtual device created by the software.
> +
> +epcs : phandle to the endpoint controller device
> +epc-names : the names of the endpoint controller device corresponding
> + to the EPCs present in the *epcs* phandle
Other than the NTB case, I'd expect the parent device to be the
controller. Let's make NTB the exception...
> +vendor-id: used to identify device manufacturer
> +device-id: used to identify a particular device
> +baseclass-code: used to classify the type of function the device performs
> +subclass-code: used to identify more specifically the function of the device
Are these codes standard?
Powerpc has "class-code" already...
> +subsys-vendor-id: used to identify vendor of the add-in card or subsystem
Powerpc has "subsystem-vendor-id" already...
> +subsys-id: used to specify an id that is specific to a vendor
> +
> +Example:
> +Following is an example of NTB device exposed to the remote host.
> +
> +ntb {
This is going to need some sort of addressing (which implies 'reg')? If
not, I don't understand why you have 2 levels.
> + compatible = "pci-epf-ntb";
> + epcs = <&pcie0_ep>, <&pcie1_ep>;
> + epc-names = "primary", "secondary";
> + vendor-id = /bits/ 16 <0x104c>;
> + device-id = /bits/ 16 <0xb00d>;
These have a long history in OF and should be 32-bits (yes, we've let
some cases of 16-bit creep in).
> + num-mws = <4>;
Doesn't this apply to more than NTB?
Can't you just get the length of 'mws-size'?
> + mws-size = <0x100000>, <0x100000>, <0x100000>, <0x100000>;
Need to support 64-bit sizes?
> +};
> --
> 2.17.1
>