Re: [PATCH v2 2/4] dt-bindings: interconnect: Add Qualcomm IPQ9574 support

[Varadarajan Narayanan <quic_varada@quicinc.com>]

On Tue, Mar 26, 2024 at 07:49:00AM +0100, Krzysztof Kozlowski wrote:
> On 25/03/2024 11:20, Varadarajan Narayanan wrote:
> > Add master/slave ids for Qualcomm IPQ9574 Network-On-Chip
> > interfaces. This will be used by the gcc-ipq9574 driver
> > that will for providing interconnect services using the
> > icc-clk framework.
> >
> > Signed-off-by: Varadarajan Narayanan <quic_varada@quicinc.com>
> > ---
> > v2: Rename master slave macros
> >     Fix license identifier
>
> Both patches should be squashed. Header is parts of bindings and your
> previous patch adds the interconnects, doesn't it?
>
>
> > ---
> >  .../dt-bindings/interconnect/qcom,ipq9574.h   | 62 +++++++++++++++++++
> >  1 file changed, 62 insertions(+)
> >  create mode 100644 include/dt-bindings/interconnect/qcom,ipq9574.h
> >
> > diff --git a/include/dt-bindings/interconnect/qcom,ipq9574.h b/include/dt-bindings/interconnect/qcom,ipq9574.h
> > new file mode 100644
> > index 000000000000..b7b32aa6bbb1
> > --- /dev/null
> > +++ b/include/dt-bindings/interconnect/qcom,ipq9574.h
> > @@ -0,0 +1,62 @@
> > +/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
> > +#ifndef INTERCONNECT_QCOM_IPQ9574_H
> > +#define INTERCONNECT_QCOM_IPQ9574_H
> > +
> > +#define IPQ_APPS_ID			9574	/* some unique value */
>
> Why random unique values are bindings? Why this cannot be 0? Please
> explain how this is used by DTS and driver.

This 'id' is not used by the driver or DTS. It is a unique id that
is initialized for the node by the interconnect driver framework.
A random value was chosen such that it does not conflict with an
already existing node id. Chose 9574 based on this comment from
clk-cbf-msm8996.c

	/* Random ID that doesn't clash with main qnoc and OSM */
	#define CBF_MASTER_NODE 2000

> > +#define IPQ_NSS_ID			(IPQ_APPS_ID * 2)
>
> This does not seem right.

Doubled the NSS id so that APPS node ids dont clash.

Thanks
Varada