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SubjectRe: [PATCH V5 10/16] dt-bindings: PCI: tegra: Add device tree support for T194
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On 5/13/2019 8:50 PM, Rob Herring wrote:
> On Tue, May 7, 2019 at 4:20 AM Vidya Sagar <vidyas@nvidia.com> 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@nvidia.com>
>>>> ---
>
>>>> +- 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.
Ok. I'll take care of it in next patch series.

>
>
>>>> +- 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.
I'm planning to remove this given we have sysfs way (Heiner's patch series @
http://patchwork.ozlabs.org/project/linux-pci/list/?series=107392 to control which ASPM states
can be enabled run time. In case if that is not going to work for a given use case, I'll push
patches separately for controlling ASPM states advertisement/working.

>
> Rob
>

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