Re: [PATCH v5 1/5] dt-bindings: arm: coresight-tnoc: Drop arm,primecell to bind on platform bus

[Jie Gan]

On 7/9/2026 4:46 PM, Krzysztof Kozlowski wrote:
> On 09/07/2026 10:34, Jie Gan wrote:
> > On 7/9/2026 3:59 PM, Krzysztof Kozlowski wrote:
> > > On Tue, Jul 07, 2026 at 05:08:49PM +0800, Jie Gan wrote:
> > > > The TNOC compatible previously required the two-string AMBA form
> > > > "qcom,coresight-tnoc", "arm,primecell", which forces the device onto the
> > > > AMBA bus.
> > > >
> > > > Change the compatible to a single "qcom,coresight-tnoc" string with no
> > > > "arm,primecell" entry, so the device is created on the platform bus and
> > > > bound by the platform driver through its compatible string.
> > >
> > > I asked already: this is not a valid reason. References to Linux
> > > structures are not correct here. If this is your reason, then answer is:
> > > fix drivers, by renaming or doing whatever is necessary to platform bus
> > > to behave like amba bus.
> >
> > The issue is that we are not allowed to introduce a DT property to
> > bypass the AMBA bus validation, which reads the Component ID (CID)
>
> It is the first time "bypass the AMBU bus validation" appears in this
> patch. You do not see that as a problem?
>
> Again, third time and the last: describe the actual hardware and the
> actual problem coming from the hardware.

Understood, will focus on describe the hardware and the hardware issue.

Commit message description updated like below:

The Aggregator TraceNoC hardware exposes CID registers, but the 
Component ID value read from those registers is 0 instead of a valid 
AMBA Component ID. As a result, the device cannot be identified by the 
AMBA bus and is not discovered as an AMBA device.

Since the hardware does not provide a valid AMBA identification, 
describe the Aggregator TraceNoC using a dedicated compatible string and 
bind it to the existing platform driver.

Thanks,
Jie

> Best regards,
> Krzysztof