Re: [PATCH V5 10/16] dt-bindings: PCI: tegra: Add device tree support for T194
From: Rob Herring
Date: Mon May 13 2019 - 11:22:39 EST
On Tue, May 7, 2019 at 4:20 AM Vidya Sagar <vidyas@xxxxxxxxxx> wrote:
> On 4/26/2019 9:13 PM, Rob Herring wrote:
> > On Wed, Apr 24, 2019 at 10:49:58AM +0530, Vidya Sagar wrote:
> >> Add support for Tegra194 PCIe controllers. These controllers are based
> >> on Synopsys DesignWare core IP.
> >> Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
> >> ---
> >> +- nvidia,bpmp: Must contain a phandle to BPMP controller node.
> >> +- nvidia,controller-id : Controller specific ID
> >> + 0: C0
> >> + 1: C1
> >> + 2: C2
> >> + 3: C3
> >> + 4: C4
> >> + 5: C5
> > We don't normal put device indexes into DT. Why do you need this.
> > Perhaps for accessing the BPMP? If so, make nvidia,bpmp a phandle+cell.
> BPMP needs to know the controller number to enable it hence it needs to be
> passed to BPMP. Just for accessing BPMP, I already added 'nvidia,bpmp' property.
Then make nvidia,bpmp take the phandle and this number.
> >> +- nvidia,disable-aspm-states: Controls advertisement of ASPM states
> >> + bit-0 to '1': Disables advertisement of ASPM-L0s
> >> + bit-1 to '1': Disables advertisement of ASPM-L1. This also disables
> >> + advertisement of ASPM-L1.1 and ASPM-L1.2
> >> + bit-2 to '1': Disables advertisement of ASPM-L1.1
> >> + bit-3 to '1': Disables advertisement of ASPM-L1.2
> > Can't this cover what 'supports-clkreq' does?
> Well, they are related partially. i.e. if a platform doesn't have 'supports-clkreq' set,
> then, by definition, it can't advertise support for ASPM L1.1 and L1.2 states. But, ASPM-L0s
> and ASPM-L1 states don't depend on 'supports-clkreq' property.
> Having this property gives more granularity as to support for which particular ASPM state
> shouldn't be advertised by the root port.
Okay, then it should be a common property then.