| Message ID | 20240110030725.710547-2-vidyas@nvidia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add support to preserve boot config in the DT flow | expand |
On Wed, Jan 10, 2024 at 08:37:24AM +0530, Vidya Sagar wrote: > The existing "linux,pci-probe-only" property applies at a system level > and it is not possible to selectively convey individual host bridge's > requirement w.r.t preserving the boot configuration done by the platform > firmware to the kernel. "preserve-boot-config" addresses that concern > and can be used to preserve the boot configuration for host bridges > selectivey. > > Signed-off-by: Vidya Sagar <vidyas@nvidia.com> > --- > V2: > * None > > Documentation/devicetree/bindings/pci/pci.txt | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/Documentation/devicetree/bindings/pci/pci.txt b/Documentation/devicetree/bindings/pci/pci.txt > index 6a8f2874a24d..0a5ff998cbe8 100644 > --- a/Documentation/devicetree/bindings/pci/pci.txt > +++ b/Documentation/devicetree/bindings/pci/pci.txt > @@ -32,6 +32,10 @@ driver implementation may support the following properties: > root port to downstream device and host bridge drivers can do programming > which depends on CLKREQ signal existence. For example, programming root port > not to advertise ASPM L1 Sub-States support if there is no CLKREQ signal. > +- preserve-boot-config: > + If present this property specifies that this host bridge is already > + configured by the platform firmware and the OS doesn't need to reconfigure > + it again. Anything new must be a schema. Don't create something new to workaround the problem. Extend the existing support. For this, make "linux,pci-probe-only" allowed in host bridge nodes. Yeah, there's the issue that this property sets a global flag, but I'd imagine the PCI maintainers would agree that some flags should/could be per bus. Rob
diff --git a/Documentation/devicetree/bindings/pci/pci.txt b/Documentation/devicetree/bindings/pci/pci.txt index 6a8f2874a24d..0a5ff998cbe8 100644 --- a/Documentation/devicetree/bindings/pci/pci.txt +++ b/Documentation/devicetree/bindings/pci/pci.txt @@ -32,6 +32,10 @@ driver implementation may support the following properties: root port to downstream device and host bridge drivers can do programming which depends on CLKREQ signal existence. For example, programming root port not to advertise ASPM L1 Sub-States support if there is no CLKREQ signal. +- preserve-boot-config: + If present this property specifies that this host bridge is already + configured by the platform firmware and the OS doesn't need to reconfigure + it again. PCI-PCI Bridge properties -------------------------
The existing "linux,pci-probe-only" property applies at a system level and it is not possible to selectively convey individual host bridge's requirement w.r.t preserving the boot configuration done by the platform firmware to the kernel. "preserve-boot-config" addresses that concern and can be used to preserve the boot configuration for host bridges selectivey. Signed-off-by: Vidya Sagar <vidyas@nvidia.com> --- V2: * None Documentation/devicetree/bindings/pci/pci.txt | 4 ++++ 1 file changed, 4 insertions(+)