2022-06-01 19:42:49

by Krzysztof Kozlowski

[permalink] [raw]
Subject: [PATCH v4 1/4] dt-bindings: interconnect: qcom,sdm845-cpu-bwmon: add BWMON device

Add bindings for the Qualcomm Bandwidth Monitor device providing
performance data on interconnects. The bindings describe only BWMON
version 4, e.g. the instance on SDM845 between CPU and Last Level Cache
Controller.

Signed-off-by: Krzysztof Kozlowski <[email protected]>
Reviewed-by: Rob Herring <[email protected]>
Acked-by: Georgi Djakov <[email protected]>
---
.../interconnect/qcom,sdm845-cpu-bwmon.yaml | 97 +++++++++++++++++++
1 file changed, 97 insertions(+)
create mode 100644 Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml

diff --git a/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
new file mode 100644
index 000000000000..8c82e06ee432
--- /dev/null
+++ b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
@@ -0,0 +1,97 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interconnect/qcom,sdm845-cpu-bwmon.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Interconnect Bandwidth Monitor
+
+maintainers:
+ - Krzysztof Kozlowski <[email protected]>
+
+description:
+ Bandwidth Monitor measures current throughput on buses between various NoC
+ fabrics and provides information when it crosses configured thresholds.
+
+properties:
+ compatible:
+ enum:
+ - qcom,sdm845-cpu-bwmon # BWMON v4
+
+ interconnects:
+ maxItems: 2
+
+ interconnect-names:
+ items:
+ - const: ddr
+ - const: l3c
+
+ interrupts:
+ maxItems: 1
+
+ operating-points-v2: true
+ opp-table: true
+
+ reg:
+ # Currently described BWMON v4 and v5 use one register address space.
+ # BWMON v2 uses two register spaces - not yet described.
+ maxItems: 1
+
+required:
+ - compatible
+ - interconnects
+ - interconnect-names
+ - interrupts
+ - operating-points-v2
+ - opp-table
+ - reg
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/interconnect/qcom,osm-l3.h>
+ #include <dt-bindings/interconnect/qcom,sdm845.h>
+ #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+ pmu@1436400 {
+ compatible = "qcom,sdm845-cpu-bwmon";
+ reg = <0x01436400 0x600>;
+
+ interrupts = <GIC_SPI 581 IRQ_TYPE_LEVEL_HIGH>;
+
+ interconnects = <&gladiator_noc MASTER_APPSS_PROC 3 &mem_noc SLAVE_EBI1 3>,
+ <&osm_l3 MASTER_OSM_L3_APPS &osm_l3 SLAVE_OSM_L3>;
+ interconnect-names = "ddr", "l3c";
+
+ operating-points-v2 = <&cpu_bwmon_opp_table>;
+
+ cpu_bwmon_opp_table: opp-table {
+ compatible = "operating-points-v2";
+
+ opp-0 {
+ opp-peak-kBps = <800000 4800000>;
+ };
+ opp-1 {
+ opp-peak-kBps = <1804000 9216000>;
+ };
+ opp-2 {
+ opp-peak-kBps = <2188000 11980800>;
+ };
+ opp-3 {
+ opp-peak-kBps = <3072000 15052800>;
+ };
+ opp-4 {
+ opp-peak-kBps = <4068000 19353600>;
+ };
+ opp-5 {
+ opp-peak-kBps = <5412000 20889600>;
+ };
+ opp-6 {
+ opp-peak-kBps = <6220000 22425600>;
+ };
+ opp-7 {
+ opp-peak-kBps = <7216000 25497600>;
+ };
+ };
+ };
--
2.34.1



2022-06-07 17:32:48

by Krzysztof Kozlowski

[permalink] [raw]
Subject: Re: [PATCH v4 1/4] dt-bindings: interconnect: qcom,sdm845-cpu-bwmon: add BWMON device

On 06/06/2022 23:11, Bjorn Andersson wrote:
> On Wed 01 Jun 03:11 PDT 2022, Krzysztof Kozlowski wrote:
>
>> Add bindings for the Qualcomm Bandwidth Monitor device providing
>> performance data on interconnects. The bindings describe only BWMON
>> version 4, e.g. the instance on SDM845 between CPU and Last Level Cache
>> Controller.
>>
>> Signed-off-by: Krzysztof Kozlowski <[email protected]>
>> Reviewed-by: Rob Herring <[email protected]>
>> Acked-by: Georgi Djakov <[email protected]>
>> ---
>> .../interconnect/qcom,sdm845-cpu-bwmon.yaml | 97 +++++++++++++++++++
>> 1 file changed, 97 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
>> new file mode 100644
>> index 000000000000..8c82e06ee432
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
>> @@ -0,0 +1,97 @@
>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/interconnect/qcom,sdm845-cpu-bwmon.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Qualcomm Interconnect Bandwidth Monitor
>> +
>> +maintainers:
>> + - Krzysztof Kozlowski <[email protected]>
>> +
>> +description:
>> + Bandwidth Monitor measures current throughput on buses between various NoC
>> + fabrics and provides information when it crosses configured thresholds.
>> +
>> +properties:
>> + compatible:
>> + enum:
>> + - qcom,sdm845-cpu-bwmon # BWMON v4
>
> It seems the thing that's called bwmon v4 is compatible with a number of
> different platforms, should we add a generic compatible to the binding
> as well, to avoid having to update the implementation for each SoC?
>
> (I.e. "qcom,sdm845-cpu-bwmon", "qcom,bwmon-v4")

I am hesitant. I could not find BWMON IP block versioning in the
Qualcomm docs. Only the downstream sources had it. Therefore I think it
is more applicable to use this one as fallback for other boards, e.g.:

"qcom,sdm660-cpu-bwmon", "qcom,sdm845-cpu-bwmon"
(even if the number is a bit odd - newer comes as last compatible).

What's your preference?

Best regards,
Krzysztof

2022-06-08 03:55:09

by Bjorn Andersson

[permalink] [raw]
Subject: Re: [PATCH v4 1/4] dt-bindings: interconnect: qcom,sdm845-cpu-bwmon: add BWMON device

On Wed 01 Jun 03:11 PDT 2022, Krzysztof Kozlowski wrote:

> Add bindings for the Qualcomm Bandwidth Monitor device providing
> performance data on interconnects. The bindings describe only BWMON
> version 4, e.g. the instance on SDM845 between CPU and Last Level Cache
> Controller.
>
> Signed-off-by: Krzysztof Kozlowski <[email protected]>
> Reviewed-by: Rob Herring <[email protected]>
> Acked-by: Georgi Djakov <[email protected]>
> ---
> .../interconnect/qcom,sdm845-cpu-bwmon.yaml | 97 +++++++++++++++++++
> 1 file changed, 97 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
>
> diff --git a/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
> new file mode 100644
> index 000000000000..8c82e06ee432
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
> @@ -0,0 +1,97 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/interconnect/qcom,sdm845-cpu-bwmon.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Qualcomm Interconnect Bandwidth Monitor
> +
> +maintainers:
> + - Krzysztof Kozlowski <[email protected]>
> +
> +description:
> + Bandwidth Monitor measures current throughput on buses between various NoC
> + fabrics and provides information when it crosses configured thresholds.
> +
> +properties:
> + compatible:
> + enum:
> + - qcom,sdm845-cpu-bwmon # BWMON v4

It seems the thing that's called bwmon v4 is compatible with a number of
different platforms, should we add a generic compatible to the binding
as well, to avoid having to update the implementation for each SoC?

(I.e. "qcom,sdm845-cpu-bwmon", "qcom,bwmon-v4")

Regards,
Bjorn

> +
> + interconnects:
> + maxItems: 2
> +
> + interconnect-names:
> + items:
> + - const: ddr
> + - const: l3c
> +
> + interrupts:
> + maxItems: 1
> +
> + operating-points-v2: true
> + opp-table: true
> +
> + reg:
> + # Currently described BWMON v4 and v5 use one register address space.
> + # BWMON v2 uses two register spaces - not yet described.
> + maxItems: 1
> +
> +required:
> + - compatible
> + - interconnects
> + - interconnect-names
> + - interrupts
> + - operating-points-v2
> + - opp-table
> + - reg
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/interconnect/qcom,osm-l3.h>
> + #include <dt-bindings/interconnect/qcom,sdm845.h>
> + #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> + pmu@1436400 {
> + compatible = "qcom,sdm845-cpu-bwmon";
> + reg = <0x01436400 0x600>;
> +
> + interrupts = <GIC_SPI 581 IRQ_TYPE_LEVEL_HIGH>;
> +
> + interconnects = <&gladiator_noc MASTER_APPSS_PROC 3 &mem_noc SLAVE_EBI1 3>,
> + <&osm_l3 MASTER_OSM_L3_APPS &osm_l3 SLAVE_OSM_L3>;
> + interconnect-names = "ddr", "l3c";
> +
> + operating-points-v2 = <&cpu_bwmon_opp_table>;
> +
> + cpu_bwmon_opp_table: opp-table {
> + compatible = "operating-points-v2";
> +
> + opp-0 {
> + opp-peak-kBps = <800000 4800000>;
> + };
> + opp-1 {
> + opp-peak-kBps = <1804000 9216000>;
> + };
> + opp-2 {
> + opp-peak-kBps = <2188000 11980800>;
> + };
> + opp-3 {
> + opp-peak-kBps = <3072000 15052800>;
> + };
> + opp-4 {
> + opp-peak-kBps = <4068000 19353600>;
> + };
> + opp-5 {
> + opp-peak-kBps = <5412000 20889600>;
> + };
> + opp-6 {
> + opp-peak-kBps = <6220000 22425600>;
> + };
> + opp-7 {
> + opp-peak-kBps = <7216000 25497600>;
> + };
> + };
> + };
> --
> 2.34.1
>

2022-06-22 12:16:53

by Rajendra Nayak

[permalink] [raw]
Subject: Re: [PATCH v4 1/4] dt-bindings: interconnect: qcom,sdm845-cpu-bwmon: add BWMON device



On 6/7/2022 12:20 PM, Krzysztof Kozlowski wrote:
> On 06/06/2022 23:11, Bjorn Andersson wrote:
>> On Wed 01 Jun 03:11 PDT 2022, Krzysztof Kozlowski wrote:
>>
>>> Add bindings for the Qualcomm Bandwidth Monitor device providing
>>> performance data on interconnects. The bindings describe only BWMON
>>> version 4, e.g. the instance on SDM845 between CPU and Last Level Cache
>>> Controller.
>>>
>>> Signed-off-by: Krzysztof Kozlowski <[email protected]>
>>> Reviewed-by: Rob Herring <[email protected]>
>>> Acked-by: Georgi Djakov <[email protected]>
>>> ---
>>> .../interconnect/qcom,sdm845-cpu-bwmon.yaml | 97 +++++++++++++++++++
>>> 1 file changed, 97 insertions(+)
>>> create mode 100644 Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
>>>
>>> diff --git a/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
>>> new file mode 100644
>>> index 000000000000..8c82e06ee432
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
>>> @@ -0,0 +1,97 @@
>>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/interconnect/qcom,sdm845-cpu-bwmon.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: Qualcomm Interconnect Bandwidth Monitor
>>> +
>>> +maintainers:
>>> + - Krzysztof Kozlowski <[email protected]>
>>> +
>>> +description:
>>> + Bandwidth Monitor measures current throughput on buses between various NoC
>>> + fabrics and provides information when it crosses configured thresholds.
>>> +
>>> +properties:
>>> + compatible:
>>> + enum:
>>> + - qcom,sdm845-cpu-bwmon # BWMON v4
>>
>> It seems the thing that's called bwmon v4 is compatible with a number of
>> different platforms, should we add a generic compatible to the binding
>> as well, to avoid having to update the implementation for each SoC?
>>
>> (I.e. "qcom,sdm845-cpu-bwmon", "qcom,bwmon-v4")

it seems pretty useful to have the "qcom,bwmon-v4" and "qcom,bwmon-v5"
compatibles, I tried these patches on a sc7280 device which has a bwmon4
between the cpu and caches (and also has a bwmon5 between the caches and DDR)
and the driver works with zero changes.

>
> I am hesitant. I could not find BWMON IP block versioning in the
> Qualcomm docs. Only the downstream sources had it. Therefore I think it
> is more applicable to use this one as fallback for other boards, e.g.:
>
> "qcom,sdm660-cpu-bwmon", "qcom,sdm845-cpu-bwmon"
> (even if the number is a bit odd - newer comes as last compatible).
>
> What's your preference?
>
> Best regards,
> Krzysztof

2022-06-22 12:32:47

by Krzysztof Kozlowski

[permalink] [raw]
Subject: Re: [PATCH v4 1/4] dt-bindings: interconnect: qcom,sdm845-cpu-bwmon: add BWMON device

On 22/06/2022 13:58, Rajendra Nayak wrote:
>
>
> On 6/7/2022 12:20 PM, Krzysztof Kozlowski wrote:
>> On 06/06/2022 23:11, Bjorn Andersson wrote:
>>> On Wed 01 Jun 03:11 PDT 2022, Krzysztof Kozlowski wrote:
>>>
>>>> Add bindings for the Qualcomm Bandwidth Monitor device providing
>>>> performance data on interconnects. The bindings describe only BWMON
>>>> version 4, e.g. the instance on SDM845 between CPU and Last Level Cache
>>>> Controller.
>>>>
>>>> Signed-off-by: Krzysztof Kozlowski <[email protected]>
>>>> Reviewed-by: Rob Herring <[email protected]>
>>>> Acked-by: Georgi Djakov <[email protected]>
>>>> ---
>>>> .../interconnect/qcom,sdm845-cpu-bwmon.yaml | 97 +++++++++++++++++++
>>>> 1 file changed, 97 insertions(+)
>>>> create mode 100644 Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
>>>> new file mode 100644
>>>> index 000000000000..8c82e06ee432
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
>>>> @@ -0,0 +1,97 @@
>>>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: http://devicetree.org/schemas/interconnect/qcom,sdm845-cpu-bwmon.yaml#
>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>> +
>>>> +title: Qualcomm Interconnect Bandwidth Monitor
>>>> +
>>>> +maintainers:
>>>> + - Krzysztof Kozlowski <[email protected]>
>>>> +
>>>> +description:
>>>> + Bandwidth Monitor measures current throughput on buses between various NoC
>>>> + fabrics and provides information when it crosses configured thresholds.
>>>> +
>>>> +properties:
>>>> + compatible:
>>>> + enum:
>>>> + - qcom,sdm845-cpu-bwmon # BWMON v4
>>>
>>> It seems the thing that's called bwmon v4 is compatible with a number of
>>> different platforms, should we add a generic compatible to the binding
>>> as well, to avoid having to update the implementation for each SoC?
>>>
>>> (I.e. "qcom,sdm845-cpu-bwmon", "qcom,bwmon-v4")
>
> it seems pretty useful to have the "qcom,bwmon-v4" and "qcom,bwmon-v5"
> compatibles, I tried these patches on a sc7280 device which has a bwmon4
> between the cpu and caches (and also has a bwmon5 between the caches and DDR)
> and the driver works with zero changes.

The trouble with naming it v4 is that such versioning does not exist in
documentation. At least I failed to find it. Neither there is clear
mapping between SoC and block version.

The only indication about BWMON versioning comes from downstream
sources, which I find not enough to justify usage of versions for blocks.

Therefore as per DT recommendation (which I am enforcing on others) I am
not planning put there bwmon-v4.

Best regards,
Krzysztof

2022-06-26 03:30:05

by Bjorn Andersson

[permalink] [raw]
Subject: Re: [PATCH v4 1/4] dt-bindings: interconnect: qcom,sdm845-cpu-bwmon: add BWMON device

On Wed 22 Jun 06:58 CDT 2022, Rajendra Nayak wrote:

>
>
> On 6/7/2022 12:20 PM, Krzysztof Kozlowski wrote:
> > On 06/06/2022 23:11, Bjorn Andersson wrote:
> > > On Wed 01 Jun 03:11 PDT 2022, Krzysztof Kozlowski wrote:
> > >
> > > > Add bindings for the Qualcomm Bandwidth Monitor device providing
> > > > performance data on interconnects. The bindings describe only BWMON
> > > > version 4, e.g. the instance on SDM845 between CPU and Last Level Cache
> > > > Controller.
> > > >
> > > > Signed-off-by: Krzysztof Kozlowski <[email protected]>
> > > > Reviewed-by: Rob Herring <[email protected]>
> > > > Acked-by: Georgi Djakov <[email protected]>
> > > > ---
> > > > .../interconnect/qcom,sdm845-cpu-bwmon.yaml | 97 +++++++++++++++++++
> > > > 1 file changed, 97 insertions(+)
> > > > create mode 100644 Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
> > > > new file mode 100644
> > > > index 000000000000..8c82e06ee432
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
> > > > @@ -0,0 +1,97 @@
> > > > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> > > > +%YAML 1.2
> > > > +---
> > > > +$id: http://devicetree.org/schemas/interconnect/qcom,sdm845-cpu-bwmon.yaml#
> > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > +
> > > > +title: Qualcomm Interconnect Bandwidth Monitor
> > > > +
> > > > +maintainers:
> > > > + - Krzysztof Kozlowski <[email protected]>
> > > > +
> > > > +description:
> > > > + Bandwidth Monitor measures current throughput on buses between various NoC
> > > > + fabrics and provides information when it crosses configured thresholds.
> > > > +
> > > > +properties:
> > > > + compatible:
> > > > + enum:
> > > > + - qcom,sdm845-cpu-bwmon # BWMON v4
> > >
> > > It seems the thing that's called bwmon v4 is compatible with a number of
> > > different platforms, should we add a generic compatible to the binding
> > > as well, to avoid having to update the implementation for each SoC?
> > >
> > > (I.e. "qcom,sdm845-cpu-bwmon", "qcom,bwmon-v4")
>
> it seems pretty useful to have the "qcom,bwmon-v4" and "qcom,bwmon-v5"
> compatibles, I tried these patches on a sc7280 device which has a bwmon4
> between the cpu and caches (and also has a bwmon5 between the caches and DDR)
> and the driver works with zero changes.
>

But does the '4' and '5' has a relation to the hardware? Or is just the
4th and 5th register layout supported by the downstream driver?

Regards,
Bjorn

2022-06-28 10:49:33

by Rajendra Nayak

[permalink] [raw]
Subject: Re: [PATCH v4 1/4] dt-bindings: interconnect: qcom,sdm845-cpu-bwmon: add BWMON device



On 6/26/2022 8:49 AM, Bjorn Andersson wrote:
> On Wed 22 Jun 06:58 CDT 2022, Rajendra Nayak wrote:
>
>>
>>
>> On 6/7/2022 12:20 PM, Krzysztof Kozlowski wrote:
>>> On 06/06/2022 23:11, Bjorn Andersson wrote:
>>>> On Wed 01 Jun 03:11 PDT 2022, Krzysztof Kozlowski wrote:
>>>>
>>>>> Add bindings for the Qualcomm Bandwidth Monitor device providing
>>>>> performance data on interconnects. The bindings describe only BWMON
>>>>> version 4, e.g. the instance on SDM845 between CPU and Last Level Cache
>>>>> Controller.
>>>>>
>>>>> Signed-off-by: Krzysztof Kozlowski <[email protected]>
>>>>> Reviewed-by: Rob Herring <[email protected]>
>>>>> Acked-by: Georgi Djakov <[email protected]>
>>>>> ---
>>>>> .../interconnect/qcom,sdm845-cpu-bwmon.yaml | 97 +++++++++++++++++++
>>>>> 1 file changed, 97 insertions(+)
>>>>> create mode 100644 Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
>>>>> new file mode 100644
>>>>> index 000000000000..8c82e06ee432
>>>>> --- /dev/null
>>>>> +++ b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
>>>>> @@ -0,0 +1,97 @@
>>>>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>>>>> +%YAML 1.2
>>>>> +---
>>>>> +$id: http://devicetree.org/schemas/interconnect/qcom,sdm845-cpu-bwmon.yaml#
>>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>>> +
>>>>> +title: Qualcomm Interconnect Bandwidth Monitor
>>>>> +
>>>>> +maintainers:
>>>>> + - Krzysztof Kozlowski <[email protected]>
>>>>> +
>>>>> +description:
>>>>> + Bandwidth Monitor measures current throughput on buses between various NoC
>>>>> + fabrics and provides information when it crosses configured thresholds.
>>>>> +
>>>>> +properties:
>>>>> + compatible:
>>>>> + enum:
>>>>> + - qcom,sdm845-cpu-bwmon # BWMON v4
>>>>
>>>> It seems the thing that's called bwmon v4 is compatible with a number of
>>>> different platforms, should we add a generic compatible to the binding
>>>> as well, to avoid having to update the implementation for each SoC?
>>>>
>>>> (I.e. "qcom,sdm845-cpu-bwmon", "qcom,bwmon-v4")
>>
>> it seems pretty useful to have the "qcom,bwmon-v4" and "qcom,bwmon-v5"
>> compatibles, I tried these patches on a sc7280 device which has a bwmon4
>> between the cpu and caches (and also has a bwmon5 between the caches and DDR)
>> and the driver works with zero changes.
>>
>
> But does the '4' and '5' has a relation to the hardware? Or is just the
> 4th and 5th register layout supported by the downstream driver?

Right, it was just based on the downstream driver register layouts, i could not
find these numbers in HW specs anywhere, but that said I do see 2 instances of
these, one of them called the LAGG bwmon which is the one between the LLCC and DDR
and is documented as part of the LLCC specs. I'll try and dig somemore into the
documentation to see how we could define compatibles to match hw revs.

>
> Regards,
> Bjorn