[PATCH RFC 0/2] Support mailbox interface in qcom,smsm driver

[PATCH RFC 0/2] Support mailbox interface in qcom,smsm driver

[Luca Weiss]

Take a shot at converting the last driver that requires direct
"qcom,ipc*" syscon references in devicetree by allowing the smsm driver
to use the mailbox interface to achieve the same effect.

I'm not very happy about how the devicetree change looks in the end.
Perhaps it's better to use mbox-names to not have <0> elements in dt,
and reference the items by name from the driver?

e.g. this change for msm8226 could be represented differently.

-		qcom,ipc-1 = <&apcs 8 13>;
-		qcom,ipc-2 = <&apcs 8 9>;
-		qcom,ipc-3 = <&apcs 8 19>;
+		mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>;

vs. for example:

-		qcom,ipc-1 = <&apcs 8 13>;
-		qcom,ipc-2 = <&apcs 8 9>;
-		qcom,ipc-3 = <&apcs 8 19>;
+		mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
+		mbox-names = "ipc-1", "ipc-2", "ipc-3";

But also here the name with 'ipc-N' is probably not particularly
fitting?

Please let me know your thoughts and any suggestions.

Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
---
Luca Weiss (2):
      dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc
      soc: qcom: smsm: Support using mailbox interface

 .../devicetree/bindings/soc/qcom/qcom,smsm.yaml    | 48 ++++++++++++++++----
 drivers/soc/qcom/smsm.c                            | 51 +++++++++++++++++++++-
 2 files changed, 90 insertions(+), 9 deletions(-)
---
base-commit: ed30a4a51bb196781c8058073ea720133a65596f
change-id: 20240424-smsm-mbox-0666f35eae44

Best regards,
-- 
Luca Weiss <luca@z3ntu.xyz>

[PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Luca Weiss]

The qcom,ipc-N properties are essentially providing a reference to a
mailbox, so allow using the mboxes property to do the same in a more
structured way.

Since multiple SMSM hosts are supported, we need to be able to provide
the correct mailbox for each host. The old qcom,ipc-N properties map to
the mboxes property by index, starting at 0 since that's a valid SMSM
host also.

The new example shows how an smsm node with just qcom,ipc-3 should be
specified with the mboxes property.

Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
---
 .../devicetree/bindings/soc/qcom/qcom,smsm.yaml    | 48 ++++++++++++++++++----
 1 file changed, 40 insertions(+), 8 deletions(-)

diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
index db67cf043256..b12589171169 100644
--- a/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
+++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
@@ -33,6 +33,13 @@ properties:
       specifier of the column in the subscription matrix representing the local
       processor.
 
+  mboxes:
+    minItems: 1
+    maxItems: 5
+    description:
+      Reference to the mailbox representing the outgoing doorbell in APCS for
+      this client.
+
   '#size-cells':
     const: 0
 
@@ -98,15 +105,18 @@ required:
   - '#address-cells'
   - '#size-cells'
 
-anyOf:
+oneOf:
   - required:
-      - qcom,ipc-1
-  - required:
-      - qcom,ipc-2
-  - required:
-      - qcom,ipc-3
-  - required:
-      - qcom,ipc-4
+      - mboxes
+  - anyOf:
+      - required:
+          - qcom,ipc-1
+      - required:
+          - qcom,ipc-2
+      - required:
+          - qcom,ipc-3
+      - required:
+          - qcom,ipc-4
 
 additionalProperties: false
 
@@ -136,3 +146,25 @@ examples:
             #interrupt-cells = <2>;
         };
     };
+  # Example using mboxes property
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    shared-memory {
+        compatible = "qcom,smsm";
+        #address-cells = <1>;
+        #size-cells = <0>;
+        mboxes = <0>, <0>, <0>, <&apcs 19>;
+
+        apps@0 {
+            reg = <0>;
+            #qcom,smem-state-cells = <1>;
+        };
+
+        wcnss@7 {
+            reg = <7>;
+            interrupts = <GIC_SPI 144 IRQ_TYPE_EDGE_RISING>;
+            interrupt-controller;
+            #interrupt-cells = <2>;
+        };
+    };

-- 
2.44.0

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Rob Herring]

On Wed, Apr 24, 2024 at 07:21:51PM +0200, Luca Weiss wrote:
> The qcom,ipc-N properties are essentially providing a reference to a
> mailbox, so allow using the mboxes property to do the same in a more
> structured way.

Can we mark qcom,ipc-N as deprecated then?
 
> Since multiple SMSM hosts are supported, we need to be able to provide
> the correct mailbox for each host. The old qcom,ipc-N properties map to
> the mboxes property by index, starting at 0 since that's a valid SMSM
> host also.
> 
> The new example shows how an smsm node with just qcom,ipc-3 should be
> specified with the mboxes property.
> 
> Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
> ---
>  .../devicetree/bindings/soc/qcom/qcom,smsm.yaml    | 48 ++++++++++++++++++----
>  1 file changed, 40 insertions(+), 8 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
> index db67cf043256..b12589171169 100644
> --- a/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
> +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
> @@ -33,6 +33,13 @@ properties:
>        specifier of the column in the subscription matrix representing the local
>        processor.
>  
> +  mboxes:
> +    minItems: 1
> +    maxItems: 5

Need to define what each entry is.

> +    description:
> +      Reference to the mailbox representing the outgoing doorbell in APCS for
> +      this client.
> +
>    '#size-cells':
>      const: 0
>  
> @@ -98,15 +105,18 @@ required:
>    - '#address-cells'
>    - '#size-cells'
>  
> -anyOf:
> +oneOf:
>    - required:
> -      - qcom,ipc-1
> -  - required:
> -      - qcom,ipc-2
> -  - required:
> -      - qcom,ipc-3
> -  - required:
> -      - qcom,ipc-4
> +      - mboxes
> +  - anyOf:
> +      - required:
> +          - qcom,ipc-1
> +      - required:
> +          - qcom,ipc-2
> +      - required:
> +          - qcom,ipc-3
> +      - required:
> +          - qcom,ipc-4
>  
>  additionalProperties: false
>  
> @@ -136,3 +146,25 @@ examples:
>              #interrupt-cells = <2>;
>          };
>      };
> +  # Example using mboxes property
> +  - |
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +    shared-memory {
> +        compatible = "qcom,smsm";
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +        mboxes = <0>, <0>, <0>, <&apcs 19>;
> +
> +        apps@0 {
> +            reg = <0>;
> +            #qcom,smem-state-cells = <1>;
> +        };
> +
> +        wcnss@7 {
> +            reg = <7>;
> +            interrupts = <GIC_SPI 144 IRQ_TYPE_EDGE_RISING>;
> +            interrupt-controller;
> +            #interrupt-cells = <2>;
> +        };
> +    };
> 
> -- 
> 2.44.0
> 

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Luca Weiss]

On Donnerstag, 25. April 2024 18:17:15 MESZ Rob Herring wrote:
> On Wed, Apr 24, 2024 at 07:21:51PM +0200, Luca Weiss wrote:
> > The qcom,ipc-N properties are essentially providing a reference to a
> > mailbox, so allow using the mboxes property to do the same in a more
> > structured way.
> 
> Can we mark qcom,ipc-N as deprecated then?

Yes, that should be ok. Will also send a similar change to the other bindings
that support both qcom,ipc and mboxes.

>  
> > Since multiple SMSM hosts are supported, we need to be able to provide
> > the correct mailbox for each host. The old qcom,ipc-N properties map to
> > the mboxes property by index, starting at 0 since that's a valid SMSM
> > host also.
> > 
> > The new example shows how an smsm node with just qcom,ipc-3 should be
> > specified with the mboxes property.
> > 
> > Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
> > ---
> >  .../devicetree/bindings/soc/qcom/qcom,smsm.yaml    | 48 ++++++++++++++++++----
> >  1 file changed, 40 insertions(+), 8 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
> > index db67cf043256..b12589171169 100644
> > --- a/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
> > +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
> > @@ -33,6 +33,13 @@ properties:
> >        specifier of the column in the subscription matrix representing the local
> >        processor.
> >  
> > +  mboxes:
> > +    minItems: 1
> > +    maxItems: 5
> 
> Need to define what each entry is.

The entry is (description from qcom,ipc-N)

  "the outgoing ipc bit used for signaling the N:th remote processor."

So you want me to add 5 times e.g.

- the IPC mailbox used for signaling the 0th remote processor
- the IPC mailbox used for signaling the 1st remote processor

etc? I don't really have any extra knowledge on smsm to be able to write
something better there..

Also what are your thoughts on this binding vs the alternative I wrote
in the cover letter? I'm not really happy about how the properties are
represented.

Regards
Luca


> 
> > +    description:
> > +      Reference to the mailbox representing the outgoing doorbell in APCS for
> > +      this client.
> > +
> >    '#size-cells':
> >      const: 0
> >  
> > @@ -98,15 +105,18 @@ required:
> >    - '#address-cells'
> >    - '#size-cells'
> >  
> > -anyOf:
> > +oneOf:
> >    - required:
> > -      - qcom,ipc-1
> > -  - required:
> > -      - qcom,ipc-2
> > -  - required:
> > -      - qcom,ipc-3
> > -  - required:
> > -      - qcom,ipc-4
> > +      - mboxes
> > +  - anyOf:
> > +      - required:
> > +          - qcom,ipc-1
> > +      - required:
> > +          - qcom,ipc-2
> > +      - required:
> > +          - qcom,ipc-3
> > +      - required:
> > +          - qcom,ipc-4
> >  
> >  additionalProperties: false
> >  
> > @@ -136,3 +146,25 @@ examples:
> >              #interrupt-cells = <2>;
> >          };
> >      };
> > +  # Example using mboxes property
> > +  - |
> > +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> > +
> > +    shared-memory {
> > +        compatible = "qcom,smsm";
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +        mboxes = <0>, <0>, <0>, <&apcs 19>;
> > +
> > +        apps@0 {
> > +            reg = <0>;
> > +            #qcom,smem-state-cells = <1>;
> > +        };
> > +
> > +        wcnss@7 {
> > +            reg = <7>;
> > +            interrupts = <GIC_SPI 144 IRQ_TYPE_EDGE_RISING>;
> > +            interrupt-controller;
> > +            #interrupt-cells = <2>;
> > +        };
> > +    };
> > 
> 

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Luca Weiss]

Hi Rob,

Any feedback on the below topic?

Regards
Luca

On Donnerstag, 25. April 2024 20:54:40 MESZ Luca Weiss wrote:
> On Donnerstag, 25. April 2024 18:17:15 MESZ Rob Herring wrote:
> > On Wed, Apr 24, 2024 at 07:21:51PM +0200, Luca Weiss wrote:
> > > The qcom,ipc-N properties are essentially providing a reference to a
> > > mailbox, so allow using the mboxes property to do the same in a more
> > > structured way.
> > 
> > Can we mark qcom,ipc-N as deprecated then?
> 
> Yes, that should be ok. Will also send a similar change to the other bindings
> that support both qcom,ipc and mboxes.
> 
> >  
> > > Since multiple SMSM hosts are supported, we need to be able to provide
> > > the correct mailbox for each host. The old qcom,ipc-N properties map to
> > > the mboxes property by index, starting at 0 since that's a valid SMSM
> > > host also.
> > > 
> > > The new example shows how an smsm node with just qcom,ipc-3 should be
> > > specified with the mboxes property.
> > > 
> > > Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
> > > ---
> > >  .../devicetree/bindings/soc/qcom/qcom,smsm.yaml    | 48 ++++++++++++++++++----
> > >  1 file changed, 40 insertions(+), 8 deletions(-)
> > > 
> > > diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
> > > index db67cf043256..b12589171169 100644
> > > --- a/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
> > > +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
> > > @@ -33,6 +33,13 @@ properties:
> > >        specifier of the column in the subscription matrix representing the local
> > >        processor.
> > >  
> > > +  mboxes:
> > > +    minItems: 1
> > > +    maxItems: 5
> > 
> > Need to define what each entry is.
> 
> The entry is (description from qcom,ipc-N)
> 
>   "the outgoing ipc bit used for signaling the N:th remote processor."
> 
> So you want me to add 5 times e.g.
> 
> - the IPC mailbox used for signaling the 0th remote processor
> - the IPC mailbox used for signaling the 1st remote processor
> 
> etc? I don't really have any extra knowledge on smsm to be able to write
> something better there..
> 
> Also what are your thoughts on this binding vs the alternative I wrote
> in the cover letter? I'm not really happy about how the properties are
> represented.
> 
> Regards
> Luca
> 
> 
> > 
> > > +    description:
> > > +      Reference to the mailbox representing the outgoing doorbell in APCS for
> > > +      this client.
> > > +
> > >    '#size-cells':
> > >      const: 0
> > >  
> > > @@ -98,15 +105,18 @@ required:
> > >    - '#address-cells'
> > >    - '#size-cells'
> > >  
> > > -anyOf:
> > > +oneOf:
> > >    - required:
> > > -      - qcom,ipc-1
> > > -  - required:
> > > -      - qcom,ipc-2
> > > -  - required:
> > > -      - qcom,ipc-3
> > > -  - required:
> > > -      - qcom,ipc-4
> > > +      - mboxes
> > > +  - anyOf:
> > > +      - required:
> > > +          - qcom,ipc-1
> > > +      - required:
> > > +          - qcom,ipc-2
> > > +      - required:
> > > +          - qcom,ipc-3
> > > +      - required:
> > > +          - qcom,ipc-4
> > >  
> > >  additionalProperties: false
> > >  
> > > @@ -136,3 +146,25 @@ examples:
> > >              #interrupt-cells = <2>;
> > >          };
> > >      };
> > > +  # Example using mboxes property
> > > +  - |
> > > +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> > > +
> > > +    shared-memory {
> > > +        compatible = "qcom,smsm";
> > > +        #address-cells = <1>;
> > > +        #size-cells = <0>;
> > > +        mboxes = <0>, <0>, <0>, <&apcs 19>;
> > > +
> > > +        apps@0 {
> > > +            reg = <0>;
> > > +            #qcom,smem-state-cells = <1>;
> > > +        };
> > > +
> > > +        wcnss@7 {
> > > +            reg = <7>;
> > > +            interrupts = <GIC_SPI 144 IRQ_TYPE_EDGE_RISING>;
> > > +            interrupt-controller;
> > > +            #interrupt-cells = <2>;
> > > +        };
> > > +    };
> > > 
> > 
> 
> 

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Krzysztof Kozlowski]

On 15/05/2024 17:06, Luca Weiss wrote:
> Hi Rob,
> 
> Any feedback on the below topic?

Can be explained in description, like
mboxes:
  description: Each entry corresponds to one remote processor
  maxItems: 5

Best regards,
Krzysztof

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Luca Weiss]

On Montag, 20. Mai 2024 08:46:39 MESZ Krzysztof Kozlowski wrote:
> On 15/05/2024 17:06, Luca Weiss wrote:
> > Hi Rob,
> > 
> > Any feedback on the below topic?
> 
> Can be explained in description, like
> mboxes:
>   description: Each entry corresponds to one remote processor
>   maxItems: 5

Hi Krzysztof

Ack, sounds good.

Maybe also from you, any opinion between these two binding styles?

So first using index of mboxes for the numbering, where for the known
usages the first element (and sometimes the 3rd - ipc-2) are empty <>.

The second variant is using mbox-names to get the correct channel-mbox
mapping.

-               qcom,ipc-1 = <&apcs 8 13>;
-               qcom,ipc-2 = <&apcs 8 9>;
-               qcom,ipc-3 = <&apcs 8 19>;
+               mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>;

vs.

-               qcom,ipc-1 = <&apcs 8 13>;
-               qcom,ipc-2 = <&apcs 8 9>;
-               qcom,ipc-3 = <&apcs 8 19>;
+               mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
+               mbox-names = "ipc-1", "ipc-2", "ipc-3";

Regards
Luca

> 
> Best regards,
> Krzysztof
> 
> 

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Krzysztof Kozlowski]

On 20/05/2024 17:11, Luca Weiss wrote:
> Hi Krzysztof
> 
> Ack, sounds good.
> 
> Maybe also from you, any opinion between these two binding styles?
> 
> So first using index of mboxes for the numbering, where for the known
> usages the first element (and sometimes the 3rd - ipc-2) are empty <>.
> 
> The second variant is using mbox-names to get the correct channel-mbox
> mapping.
> 
> -               qcom,ipc-1 = <&apcs 8 13>;
> -               qcom,ipc-2 = <&apcs 8 9>;
> -               qcom,ipc-3 = <&apcs 8 19>;
> +               mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>;
> 
> vs.
> 
> -               qcom,ipc-1 = <&apcs 8 13>;
> -               qcom,ipc-2 = <&apcs 8 9>;
> -               qcom,ipc-3 = <&apcs 8 19>;
> +               mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
> +               mbox-names = "ipc-1", "ipc-2", "ipc-3";

Sorry, don't get, ipc-1 is the first mailbox, so why would there be <0>
in first case? Anyway, the question is if you need to know that some
mailbox is missing. But then it is weird to name them "ipc-1" etc.

Best regards,
Krzysztof

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Luca Weiss]

On Dienstag, 21. Mai 2024 10:58:07 MESZ Krzysztof Kozlowski wrote:
> On 20/05/2024 17:11, Luca Weiss wrote:
> > Hi Krzysztof
> > 
> > Ack, sounds good.
> > 
> > Maybe also from you, any opinion between these two binding styles?
> > 
> > So first using index of mboxes for the numbering, where for the known
> > usages the first element (and sometimes the 3rd - ipc-2) are empty <>.
> > 
> > The second variant is using mbox-names to get the correct channel-mbox
> > mapping.
> > 
> > -               qcom,ipc-1 = <&apcs 8 13>;
> > -               qcom,ipc-2 = <&apcs 8 9>;
> > -               qcom,ipc-3 = <&apcs 8 19>;
> > +               mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>;
> > 
> > vs.
> > 
> > -               qcom,ipc-1 = <&apcs 8 13>;
> > -               qcom,ipc-2 = <&apcs 8 9>;
> > -               qcom,ipc-3 = <&apcs 8 19>;
> > +               mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
> > +               mbox-names = "ipc-1", "ipc-2", "ipc-3";
> 
> Sorry, don't get, ipc-1 is the first mailbox, so why would there be <0>
> in first case?

Actually not, ipc-0 would be permissible by the driver, used for the 0th host

e.g. from:

	/* Iterate over all hosts to check whom wants a kick */
	for (host = 0; host < smsm->num_hosts; host++) {
		hostp = &smsm->hosts[host];

Even though no mailbox is specified in any upstream dts for this 0th host I
didn't want the bindings to restrict that, that's why in the first example
there's an empty element (<0>) for the 0th smsm host

> Anyway, the question is if you need to know that some
> mailbox is missing. But then it is weird to name them "ipc-1" etc.

In either case we'd just query the mbox (either by name or index) and then
see if it's there? Not quite sure I understand the sentence..
Pretty sure either binding would work the same way.

Regards
Luca

> 
> Best regards,
> Krzysztof
> 
> 

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Krzysztof Kozlowski]

On 21/05/2024 22:35, Luca Weiss wrote:
> On Dienstag, 21. Mai 2024 10:58:07 MESZ Krzysztof Kozlowski wrote:
>> On 20/05/2024 17:11, Luca Weiss wrote:
>>> Hi Krzysztof
>>>
>>> Ack, sounds good.
>>>
>>> Maybe also from you, any opinion between these two binding styles?
>>>
>>> So first using index of mboxes for the numbering, where for the known
>>> usages the first element (and sometimes the 3rd - ipc-2) are empty <>.
>>>
>>> The second variant is using mbox-names to get the correct channel-mbox
>>> mapping.
>>>
>>> -               qcom,ipc-1 = <&apcs 8 13>;
>>> -               qcom,ipc-2 = <&apcs 8 9>;
>>> -               qcom,ipc-3 = <&apcs 8 19>;
>>> +               mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>;
>>>
>>> vs.
>>>
>>> -               qcom,ipc-1 = <&apcs 8 13>;
>>> -               qcom,ipc-2 = <&apcs 8 9>;
>>> -               qcom,ipc-3 = <&apcs 8 19>;
>>> +               mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
>>> +               mbox-names = "ipc-1", "ipc-2", "ipc-3";
>>
>> Sorry, don't get, ipc-1 is the first mailbox, so why would there be <0>
>> in first case?
> 
> Actually not, ipc-0 would be permissible by the driver, used for the 0th host
> 
> e.g. from:
> 
> 	/* Iterate over all hosts to check whom wants a kick */
> 	for (host = 0; host < smsm->num_hosts; host++) {
> 		hostp = &smsm->hosts[host];
> 
> Even though no mailbox is specified in any upstream dts for this 0th host I
> didn't want the bindings to restrict that, that's why in the first example
> there's an empty element (<0>) for the 0th smsm host
> 
>> Anyway, the question is if you need to know that some
>> mailbox is missing. But then it is weird to name them "ipc-1" etc.
> 
> In either case we'd just query the mbox (either by name or index) and then
> see if it's there? Not quite sure I understand the sentence..
> Pretty sure either binding would work the same way.

The question is: does the driver care only about having some mailboxes
or the driver cares about each specific mailbox? IOW, is skipping ipc-0
important for the driver?


Best regards,
Krzysztof

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Luca Weiss]

On Mittwoch, 22. Mai 2024 08:49:43 MESZ Krzysztof Kozlowski wrote:
> On 21/05/2024 22:35, Luca Weiss wrote:
> > On Dienstag, 21. Mai 2024 10:58:07 MESZ Krzysztof Kozlowski wrote:
> >> On 20/05/2024 17:11, Luca Weiss wrote:
> >>> Hi Krzysztof
> >>>
> >>> Ack, sounds good.
> >>>
> >>> Maybe also from you, any opinion between these two binding styles?
> >>>
> >>> So first using index of mboxes for the numbering, where for the known
> >>> usages the first element (and sometimes the 3rd - ipc-2) are empty <>.
> >>>
> >>> The second variant is using mbox-names to get the correct channel-mbox
> >>> mapping.
> >>>
> >>> -               qcom,ipc-1 = <&apcs 8 13>;
> >>> -               qcom,ipc-2 = <&apcs 8 9>;
> >>> -               qcom,ipc-3 = <&apcs 8 19>;
> >>> +               mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>;
> >>>
> >>> vs.
> >>>
> >>> -               qcom,ipc-1 = <&apcs 8 13>;
> >>> -               qcom,ipc-2 = <&apcs 8 9>;
> >>> -               qcom,ipc-3 = <&apcs 8 19>;
> >>> +               mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
> >>> +               mbox-names = "ipc-1", "ipc-2", "ipc-3";
> >>
> >> Sorry, don't get, ipc-1 is the first mailbox, so why would there be <0>
> >> in first case?
> > 
> > Actually not, ipc-0 would be permissible by the driver, used for the 0th host
> > 
> > e.g. from:
> > 
> > 	/* Iterate over all hosts to check whom wants a kick */
> > 	for (host = 0; host < smsm->num_hosts; host++) {
> > 		hostp = &smsm->hosts[host];
> > 
> > Even though no mailbox is specified in any upstream dts for this 0th host I
> > didn't want the bindings to restrict that, that's why in the first example
> > there's an empty element (<0>) for the 0th smsm host
> > 
> >> Anyway, the question is if you need to know that some
> >> mailbox is missing. But then it is weird to name them "ipc-1" etc.
> > 
> > In either case we'd just query the mbox (either by name or index) and then
> > see if it's there? Not quite sure I understand the sentence..
> > Pretty sure either binding would work the same way.
> 
> The question is: does the driver care only about having some mailboxes
> or the driver cares about each specific mailbox? IOW, is skipping ipc-0
> important for the driver?

There's nothing special from driver side about any mailbox. Some SoCs have
a mailbox for e.g. hosts 1&2&3, some have only 1&3, and apq8064 even has
1&2&3&4.

And if the driver doesn't find a mailbox for a host, it just ignores it
but then of course it can't 'ring' the mailbox for that host when necessary.

Not sure how much more I can add here, to be fair I barely understand what
this driver is doing myself apart from the obvious.

Regards
Luca

> 
> 
> Best regards,
> Krzysztof
> 
> 

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Krzysztof Kozlowski]

On 22/05/2024 19:34, Luca Weiss wrote:
> On Mittwoch, 22. Mai 2024 08:49:43 MESZ Krzysztof Kozlowski wrote:
>> On 21/05/2024 22:35, Luca Weiss wrote:
>>> On Dienstag, 21. Mai 2024 10:58:07 MESZ Krzysztof Kozlowski wrote:
>>>> On 20/05/2024 17:11, Luca Weiss wrote:
>>>>> Hi Krzysztof
>>>>>
>>>>> Ack, sounds good.
>>>>>
>>>>> Maybe also from you, any opinion between these two binding styles?
>>>>>
>>>>> So first using index of mboxes for the numbering, where for the known
>>>>> usages the first element (and sometimes the 3rd - ipc-2) are empty <>.
>>>>>
>>>>> The second variant is using mbox-names to get the correct channel-mbox
>>>>> mapping.
>>>>>
>>>>> -               qcom,ipc-1 = <&apcs 8 13>;
>>>>> -               qcom,ipc-2 = <&apcs 8 9>;
>>>>> -               qcom,ipc-3 = <&apcs 8 19>;
>>>>> +               mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>;
>>>>>
>>>>> vs.
>>>>>
>>>>> -               qcom,ipc-1 = <&apcs 8 13>;
>>>>> -               qcom,ipc-2 = <&apcs 8 9>;
>>>>> -               qcom,ipc-3 = <&apcs 8 19>;
>>>>> +               mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
>>>>> +               mbox-names = "ipc-1", "ipc-2", "ipc-3";
>>>>
>>>> Sorry, don't get, ipc-1 is the first mailbox, so why would there be <0>
>>>> in first case?
>>>
>>> Actually not, ipc-0 would be permissible by the driver, used for the 0th host
>>>
>>> e.g. from:
>>>
>>> 	/* Iterate over all hosts to check whom wants a kick */
>>> 	for (host = 0; host < smsm->num_hosts; host++) {
>>> 		hostp = &smsm->hosts[host];
>>>
>>> Even though no mailbox is specified in any upstream dts for this 0th host I
>>> didn't want the bindings to restrict that, that's why in the first example
>>> there's an empty element (<0>) for the 0th smsm host
>>>
>>>> Anyway, the question is if you need to know that some
>>>> mailbox is missing. But then it is weird to name them "ipc-1" etc.
>>>
>>> In either case we'd just query the mbox (either by name or index) and then
>>> see if it's there? Not quite sure I understand the sentence..
>>> Pretty sure either binding would work the same way.
>>
>> The question is: does the driver care only about having some mailboxes
>> or the driver cares about each specific mailbox? IOW, is skipping ipc-0
>> important for the driver?
> 
> There's nothing special from driver side about any mailbox. Some SoCs have
> a mailbox for e.g. hosts 1&2&3, some have only 1&3, and apq8064 even has
> 1&2&3&4.
> 
> And if the driver doesn't find a mailbox for a host, it just ignores it
> but then of course it can't 'ring' the mailbox for that host when necessary.
> 
> Not sure how much more I can add here, to be fair I barely understand what
> this driver is doing myself apart from the obvious.

From what you said, it looks like it is enough to just list mailboxes,
e.g. for ipc-1, ipc-2 and ipc-4 (so no ipc-0 and ipc-3):

mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;

Best regards,
Krzysztof

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Luca Weiss]

On Donnerstag, 23. Mai 2024 08:02:13 MESZ Krzysztof Kozlowski wrote:
> On 22/05/2024 19:34, Luca Weiss wrote:
> > On Mittwoch, 22. Mai 2024 08:49:43 MESZ Krzysztof Kozlowski wrote:
> >> On 21/05/2024 22:35, Luca Weiss wrote:
> >>> On Dienstag, 21. Mai 2024 10:58:07 MESZ Krzysztof Kozlowski wrote:
> >>>> On 20/05/2024 17:11, Luca Weiss wrote:
> >>>>> Hi Krzysztof
> >>>>>
> >>>>> Ack, sounds good.
> >>>>>
> >>>>> Maybe also from you, any opinion between these two binding styles?
> >>>>>
> >>>>> So first using index of mboxes for the numbering, where for the known
> >>>>> usages the first element (and sometimes the 3rd - ipc-2) are empty <>.
> >>>>>
> >>>>> The second variant is using mbox-names to get the correct channel-mbox
> >>>>> mapping.
> >>>>>
> >>>>> -               qcom,ipc-1 = <&apcs 8 13>;
> >>>>> -               qcom,ipc-2 = <&apcs 8 9>;
> >>>>> -               qcom,ipc-3 = <&apcs 8 19>;
> >>>>> +               mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>;
> >>>>>
> >>>>> vs.
> >>>>>
> >>>>> -               qcom,ipc-1 = <&apcs 8 13>;
> >>>>> -               qcom,ipc-2 = <&apcs 8 9>;
> >>>>> -               qcom,ipc-3 = <&apcs 8 19>;
> >>>>> +               mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
> >>>>> +               mbox-names = "ipc-1", "ipc-2", "ipc-3";
> >>>>
> >>>> Sorry, don't get, ipc-1 is the first mailbox, so why would there be <0>
> >>>> in first case?
> >>>
> >>> Actually not, ipc-0 would be permissible by the driver, used for the 0th host
> >>>
> >>> e.g. from:
> >>>
> >>> 	/* Iterate over all hosts to check whom wants a kick */
> >>> 	for (host = 0; host < smsm->num_hosts; host++) {
> >>> 		hostp = &smsm->hosts[host];
> >>>
> >>> Even though no mailbox is specified in any upstream dts for this 0th host I
> >>> didn't want the bindings to restrict that, that's why in the first example
> >>> there's an empty element (<0>) for the 0th smsm host
> >>>
> >>>> Anyway, the question is if you need to know that some
> >>>> mailbox is missing. But then it is weird to name them "ipc-1" etc.
> >>>
> >>> In either case we'd just query the mbox (either by name or index) and then
> >>> see if it's there? Not quite sure I understand the sentence..
> >>> Pretty sure either binding would work the same way.
> >>
> >> The question is: does the driver care only about having some mailboxes
> >> or the driver cares about each specific mailbox? IOW, is skipping ipc-0
> >> important for the driver?
> > 
> > There's nothing special from driver side about any mailbox. Some SoCs have
> > a mailbox for e.g. hosts 1&2&3, some have only 1&3, and apq8064 even has
> > 1&2&3&4.
> > 
> > And if the driver doesn't find a mailbox for a host, it just ignores it
> > but then of course it can't 'ring' the mailbox for that host when necessary.
> > 
> > Not sure how much more I can add here, to be fair I barely understand what
> > this driver is doing myself apart from the obvious.
> 
> From what you said, it looks like it is enough to just list mailboxes,
> e.g. for ipc-1, ipc-2 and ipc-4 (so no ipc-0 and ipc-3):

No, for sure we need also the possibility to list ipc-3.

And my point is that I'm not sure if any platform will ever need ipc-0, but
the code to use that if it ever exists is there - the driver always
tries getting an mbox (currently just syscon of course) for every host
from 0 to n.

These are the current (non-mbox-API) mboxes provided to smsm:

$ git grep qcom,ipc- arch/
arch/arm/boot/dts/qcom/qcom-apq8064.dtsi:               qcom,ipc-1 = <&l2cc 8 4>;
arch/arm/boot/dts/qcom/qcom-apq8064.dtsi:               qcom,ipc-2 = <&l2cc 8 14>;
arch/arm/boot/dts/qcom/qcom-apq8064.dtsi:               qcom,ipc-3 = <&l2cc 8 23>;
arch/arm/boot/dts/qcom/qcom-apq8064.dtsi:               qcom,ipc-4 = <&sps_sic_non_secure 0x4094 0>;
arch/arm/boot/dts/qcom/qcom-msm8974.dtsi:               qcom,ipc-1 = <&apcs 8 13>;
arch/arm/boot/dts/qcom/qcom-msm8974.dtsi:               qcom,ipc-2 = <&apcs 8 9>;
arch/arm/boot/dts/qcom/qcom-msm8974.dtsi:               qcom,ipc-3 = <&apcs 8 19>;
arch/arm64/boot/dts/qcom/msm8916.dtsi:          qcom,ipc-1 = <&apcs 8 13>;
arch/arm64/boot/dts/qcom/msm8916.dtsi:          qcom,ipc-3 = <&apcs 8 19>;
arch/arm64/boot/dts/qcom/msm8939.dtsi:          qcom,ipc-1 = <&apcs1_mbox 8 13>;
arch/arm64/boot/dts/qcom/msm8939.dtsi:          qcom,ipc-3 = <&apcs1_mbox 8 19>;
arch/arm64/boot/dts/qcom/msm8953.dtsi:          qcom,ipc-1 = <&apcs 8 13>;
arch/arm64/boot/dts/qcom/msm8953.dtsi:          qcom,ipc-3 = <&apcs 8 19>;
arch/arm64/boot/dts/qcom/msm8976.dtsi:          qcom,ipc-1 = <&apcs 8 13>;
arch/arm64/boot/dts/qcom/msm8976.dtsi:          qcom,ipc-2 = <&apcs 8 9>;
arch/arm64/boot/dts/qcom/msm8976.dtsi:          qcom,ipc-3 = <&apcs 8 19>;

> 
> mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
> 
> Best regards,
> Krzysztof
> 
> 

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Krzysztof Kozlowski]

On 23/05/2024 08:16, Luca Weiss wrote:
> On Donnerstag, 23. Mai 2024 08:02:13 MESZ Krzysztof Kozlowski wrote:
>> On 22/05/2024 19:34, Luca Weiss wrote:
>>> On Mittwoch, 22. Mai 2024 08:49:43 MESZ Krzysztof Kozlowski wrote:
>>>> On 21/05/2024 22:35, Luca Weiss wrote:
>>>>> On Dienstag, 21. Mai 2024 10:58:07 MESZ Krzysztof Kozlowski wrote:
>>>>>> On 20/05/2024 17:11, Luca Weiss wrote:
>>>>>>> Hi Krzysztof
>>>>>>>
>>>>>>> Ack, sounds good.
>>>>>>>
>>>>>>> Maybe also from you, any opinion between these two binding styles?
>>>>>>>
>>>>>>> So first using index of mboxes for the numbering, where for the known
>>>>>>> usages the first element (and sometimes the 3rd - ipc-2) are empty <>.
>>>>>>>
>>>>>>> The second variant is using mbox-names to get the correct channel-mbox
>>>>>>> mapping.
>>>>>>>
>>>>>>> -               qcom,ipc-1 = <&apcs 8 13>;
>>>>>>> -               qcom,ipc-2 = <&apcs 8 9>;
>>>>>>> -               qcom,ipc-3 = <&apcs 8 19>;
>>>>>>> +               mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>;
>>>>>>>
>>>>>>> vs.
>>>>>>>
>>>>>>> -               qcom,ipc-1 = <&apcs 8 13>;
>>>>>>> -               qcom,ipc-2 = <&apcs 8 9>;
>>>>>>> -               qcom,ipc-3 = <&apcs 8 19>;
>>>>>>> +               mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
>>>>>>> +               mbox-names = "ipc-1", "ipc-2", "ipc-3";
>>>>>>
>>>>>> Sorry, don't get, ipc-1 is the first mailbox, so why would there be <0>
>>>>>> in first case?
>>>>>
>>>>> Actually not, ipc-0 would be permissible by the driver, used for the 0th host
>>>>>
>>>>> e.g. from:
>>>>>
>>>>> 	/* Iterate over all hosts to check whom wants a kick */
>>>>> 	for (host = 0; host < smsm->num_hosts; host++) {
>>>>> 		hostp = &smsm->hosts[host];
>>>>>
>>>>> Even though no mailbox is specified in any upstream dts for this 0th host I
>>>>> didn't want the bindings to restrict that, that's why in the first example
>>>>> there's an empty element (<0>) for the 0th smsm host
>>>>>
>>>>>> Anyway, the question is if you need to know that some
>>>>>> mailbox is missing. But then it is weird to name them "ipc-1" etc.
>>>>>
>>>>> In either case we'd just query the mbox (either by name or index) and then
>>>>> see if it's there? Not quite sure I understand the sentence..
>>>>> Pretty sure either binding would work the same way.
>>>>
>>>> The question is: does the driver care only about having some mailboxes
>>>> or the driver cares about each specific mailbox? IOW, is skipping ipc-0
>>>> important for the driver?
>>>
>>> There's nothing special from driver side about any mailbox. Some SoCs have
>>> a mailbox for e.g. hosts 1&2&3, some have only 1&3, and apq8064 even has
>>> 1&2&3&4.
>>>
>>> And if the driver doesn't find a mailbox for a host, it just ignores it
>>> but then of course it can't 'ring' the mailbox for that host when necessary.
>>>
>>> Not sure how much more I can add here, to be fair I barely understand what
>>> this driver is doing myself apart from the obvious.
>>
>> From what you said, it looks like it is enough to just list mailboxes,
>> e.g. for ipc-1, ipc-2 and ipc-4 (so no ipc-0 and ipc-3):
> 
> No, for sure we need also the possibility to list ipc-3.

? You can list it, what's the problem>

> 
> And my point is that I'm not sure if any platform will ever need ipc-0, but
> the code to use that if it ever exists is there - the driver always
> tries getting an mbox (currently just syscon of course) for every host
> from 0 to n.
> 
> These are the current (non-mbox-API) mboxes provided to smsm:
> 
> $ git grep qcom,ipc- arch/
> arch/arm/boot/dts/qcom/qcom-apq8064.dtsi:               qcom,ipc-1 = <&l2cc 8 4>;
> arch/arm/boot/dts/qcom/qcom-apq8064.dtsi:               qcom,ipc-2 = <&l2cc 8 14>;
> arch/arm/boot/dts/qcom/qcom-apq8064.dtsi:               qcom,ipc-3 = <&l2cc 8 23>;
> arch/arm/boot/dts/qcom/qcom-apq8064.dtsi:               qcom,ipc-4 = <&sps_sic_non_secure 0x4094 0>;
> arch/arm/boot/dts/qcom/qcom-msm8974.dtsi:               qcom,ipc-1 = <&apcs 8 13>;
> arch/arm/boot/dts/qcom/qcom-msm8974.dtsi:               qcom,ipc-2 = <&apcs 8 9>;
> arch/arm/boot/dts/qcom/qcom-msm8974.dtsi:               qcom,ipc-3 = <&apcs 8 19>;
> arch/arm64/boot/dts/qcom/msm8916.dtsi:          qcom,ipc-1 = <&apcs 8 13>;
> arch/arm64/boot/dts/qcom/msm8916.dtsi:          qcom,ipc-3 = <&apcs 8 19>;
> arch/arm64/boot/dts/qcom/msm8939.dtsi:          qcom,ipc-1 = <&apcs1_mbox 8 13>;
> arch/arm64/boot/dts/qcom/msm8939.dtsi:          qcom,ipc-3 = <&apcs1_mbox 8 19>;
> arch/arm64/boot/dts/qcom/msm8953.dtsi:          qcom,ipc-1 = <&apcs 8 13>;
> arch/arm64/boot/dts/qcom/msm8953.dtsi:          qcom,ipc-3 = <&apcs 8 19>;
> arch/arm64/boot/dts/qcom/msm8976.dtsi:          qcom,ipc-1 = <&apcs 8 13>;
> arch/arm64/boot/dts/qcom/msm8976.dtsi:          qcom,ipc-2 = <&apcs 8 9>;
> arch/arm64/boot/dts/qcom/msm8976.dtsi:          qcom,ipc-3 = <&apcs 8 19>;
> 
>>
>> mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;

So which case is not covered?

Best regards,
Krzysztof

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Luca Weiss]

On Donnerstag, 23. Mai 2024 08:19:11 MESZ Krzysztof Kozlowski wrote:
> On 23/05/2024 08:16, Luca Weiss wrote:
> > On Donnerstag, 23. Mai 2024 08:02:13 MESZ Krzysztof Kozlowski wrote:
> >> On 22/05/2024 19:34, Luca Weiss wrote:
> >>> On Mittwoch, 22. Mai 2024 08:49:43 MESZ Krzysztof Kozlowski wrote:
> >>>> On 21/05/2024 22:35, Luca Weiss wrote:
> >>>>> On Dienstag, 21. Mai 2024 10:58:07 MESZ Krzysztof Kozlowski wrote:
> >>>>>> On 20/05/2024 17:11, Luca Weiss wrote:
> >>>>>>> Hi Krzysztof
> >>>>>>>
> >>>>>>> Ack, sounds good.
> >>>>>>>
> >>>>>>> Maybe also from you, any opinion between these two binding styles?
> >>>>>>>
> >>>>>>> So first using index of mboxes for the numbering, where for the known
> >>>>>>> usages the first element (and sometimes the 3rd - ipc-2) are empty <>.
> >>>>>>>
> >>>>>>> The second variant is using mbox-names to get the correct channel-mbox
> >>>>>>> mapping.
> >>>>>>>
> >>>>>>> -               qcom,ipc-1 = <&apcs 8 13>;
> >>>>>>> -               qcom,ipc-2 = <&apcs 8 9>;
> >>>>>>> -               qcom,ipc-3 = <&apcs 8 19>;
> >>>>>>> +               mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>;
> >>>>>>>
> >>>>>>> vs.
> >>>>>>>
> >>>>>>> -               qcom,ipc-1 = <&apcs 8 13>;
> >>>>>>> -               qcom,ipc-2 = <&apcs 8 9>;
> >>>>>>> -               qcom,ipc-3 = <&apcs 8 19>;
> >>>>>>> +               mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
> >>>>>>> +               mbox-names = "ipc-1", "ipc-2", "ipc-3";
> >>>>>>
> >>>>>> Sorry, don't get, ipc-1 is the first mailbox, so why would there be <0>
> >>>>>> in first case?
> >>>>>
> >>>>> Actually not, ipc-0 would be permissible by the driver, used for the 0th host
> >>>>>
> >>>>> e.g. from:
> >>>>>
> >>>>> 	/* Iterate over all hosts to check whom wants a kick */
> >>>>> 	for (host = 0; host < smsm->num_hosts; host++) {
> >>>>> 		hostp = &smsm->hosts[host];
> >>>>>
> >>>>> Even though no mailbox is specified in any upstream dts for this 0th host I
> >>>>> didn't want the bindings to restrict that, that's why in the first example
> >>>>> there's an empty element (<0>) for the 0th smsm host
> >>>>>
> >>>>>> Anyway, the question is if you need to know that some
> >>>>>> mailbox is missing. But then it is weird to name them "ipc-1" etc.
> >>>>>
> >>>>> In either case we'd just query the mbox (either by name or index) and then
> >>>>> see if it's there? Not quite sure I understand the sentence..
> >>>>> Pretty sure either binding would work the same way.
> >>>>
> >>>> The question is: does the driver care only about having some mailboxes
> >>>> or the driver cares about each specific mailbox? IOW, is skipping ipc-0
> >>>> important for the driver?
> >>>
> >>> There's nothing special from driver side about any mailbox. Some SoCs have
> >>> a mailbox for e.g. hosts 1&2&3, some have only 1&3, and apq8064 even has
> >>> 1&2&3&4.
> >>>
> >>> And if the driver doesn't find a mailbox for a host, it just ignores it
> >>> but then of course it can't 'ring' the mailbox for that host when necessary.
> >>>
> >>> Not sure how much more I can add here, to be fair I barely understand what
> >>> this driver is doing myself apart from the obvious.
> >>
> >> From what you said, it looks like it is enough to just list mailboxes,
> >> e.g. for ipc-1, ipc-2 and ipc-4 (so no ipc-0 and ipc-3):
> > 
> > No, for sure we need also the possibility to list ipc-3.
> 
> ? You can list it, what's the problem>

Maybe we're talking past each other...

You asked why this wouldn't work:

  e.g. for ipc-1, ipc-2 and ipc-4 (so no ipc-0 and ipc-3):
  mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;

How would we know that the 3rd mailbox (&apcs 19) is for the 4th host
(previous ipc-4)?

1. If we use mboxes with indexes we'd need to have <0> values for
"smsm hosts" where we don't have a mailbox for - this is at least
for the 2nd smsm host (qcom,ipc-2) for a bunch of SoCs.

2. If we use mboxes with mbox-names then we could skip that since we
can directly specify which "smsm host" a given mailbox is for.

My only question really is whether 1. or 2. is a better idea.

Is this clearer now or still not?


> 
> > 
> > And my point is that I'm not sure if any platform will ever need ipc-0, but
> > the code to use that if it ever exists is there - the driver always
> > tries getting an mbox (currently just syscon of course) for every host
> > from 0 to n.
> > 
> > These are the current (non-mbox-API) mboxes provided to smsm:
> > 
> > $ git grep qcom,ipc- arch/
> > arch/arm/boot/dts/qcom/qcom-apq8064.dtsi:               qcom,ipc-1 = <&l2cc 8 4>;
> > arch/arm/boot/dts/qcom/qcom-apq8064.dtsi:               qcom,ipc-2 = <&l2cc 8 14>;
> > arch/arm/boot/dts/qcom/qcom-apq8064.dtsi:               qcom,ipc-3 = <&l2cc 8 23>;
> > arch/arm/boot/dts/qcom/qcom-apq8064.dtsi:               qcom,ipc-4 = <&sps_sic_non_secure 0x4094 0>;
> > arch/arm/boot/dts/qcom/qcom-msm8974.dtsi:               qcom,ipc-1 = <&apcs 8 13>;
> > arch/arm/boot/dts/qcom/qcom-msm8974.dtsi:               qcom,ipc-2 = <&apcs 8 9>;
> > arch/arm/boot/dts/qcom/qcom-msm8974.dtsi:               qcom,ipc-3 = <&apcs 8 19>;
> > arch/arm64/boot/dts/qcom/msm8916.dtsi:          qcom,ipc-1 = <&apcs 8 13>;
> > arch/arm64/boot/dts/qcom/msm8916.dtsi:          qcom,ipc-3 = <&apcs 8 19>;
> > arch/arm64/boot/dts/qcom/msm8939.dtsi:          qcom,ipc-1 = <&apcs1_mbox 8 13>;
> > arch/arm64/boot/dts/qcom/msm8939.dtsi:          qcom,ipc-3 = <&apcs1_mbox 8 19>;
> > arch/arm64/boot/dts/qcom/msm8953.dtsi:          qcom,ipc-1 = <&apcs 8 13>;
> > arch/arm64/boot/dts/qcom/msm8953.dtsi:          qcom,ipc-3 = <&apcs 8 19>;
> > arch/arm64/boot/dts/qcom/msm8976.dtsi:          qcom,ipc-1 = <&apcs 8 13>;
> > arch/arm64/boot/dts/qcom/msm8976.dtsi:          qcom,ipc-2 = <&apcs 8 9>;
> > arch/arm64/boot/dts/qcom/msm8976.dtsi:          qcom,ipc-3 = <&apcs 8 19>;
> > 
> >>
> >> mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
> 
> So which case is not covered?
> 
> Best regards,
> Krzysztof
> 
> 

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Krzysztof Kozlowski]

On 24/05/2024 19:55, Luca Weiss wrote:
> On Donnerstag, 23. Mai 2024 08:19:11 MESZ Krzysztof Kozlowski wrote:
>> On 23/05/2024 08:16, Luca Weiss wrote:
>>> On Donnerstag, 23. Mai 2024 08:02:13 MESZ Krzysztof Kozlowski wrote:
>>>> On 22/05/2024 19:34, Luca Weiss wrote:
>>>>> On Mittwoch, 22. Mai 2024 08:49:43 MESZ Krzysztof Kozlowski wrote:
>>>>>> On 21/05/2024 22:35, Luca Weiss wrote:
>>>>>>> On Dienstag, 21. Mai 2024 10:58:07 MESZ Krzysztof Kozlowski wrote:
>>>>>>>> On 20/05/2024 17:11, Luca Weiss wrote:
>>>>>>>>> Hi Krzysztof
>>>>>>>>>
>>>>>>>>> Ack, sounds good.
>>>>>>>>>
>>>>>>>>> Maybe also from you, any opinion between these two binding styles?
>>>>>>>>>
>>>>>>>>> So first using index of mboxes for the numbering, where for the known
>>>>>>>>> usages the first element (and sometimes the 3rd - ipc-2) are empty <>.
>>>>>>>>>
>>>>>>>>> The second variant is using mbox-names to get the correct channel-mbox
>>>>>>>>> mapping.
>>>>>>>>>
>>>>>>>>> -               qcom,ipc-1 = <&apcs 8 13>;
>>>>>>>>> -               qcom,ipc-2 = <&apcs 8 9>;
>>>>>>>>> -               qcom,ipc-3 = <&apcs 8 19>;
>>>>>>>>> +               mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>;
>>>>>>>>>
>>>>>>>>> vs.
>>>>>>>>>
>>>>>>>>> -               qcom,ipc-1 = <&apcs 8 13>;
>>>>>>>>> -               qcom,ipc-2 = <&apcs 8 9>;
>>>>>>>>> -               qcom,ipc-3 = <&apcs 8 19>;
>>>>>>>>> +               mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
>>>>>>>>> +               mbox-names = "ipc-1", "ipc-2", "ipc-3";
>>>>>>>>
>>>>>>>> Sorry, don't get, ipc-1 is the first mailbox, so why would there be <0>
>>>>>>>> in first case?
>>>>>>>
>>>>>>> Actually not, ipc-0 would be permissible by the driver, used for the 0th host
>>>>>>>
>>>>>>> e.g. from:
>>>>>>>
>>>>>>> 	/* Iterate over all hosts to check whom wants a kick */
>>>>>>> 	for (host = 0; host < smsm->num_hosts; host++) {
>>>>>>> 		hostp = &smsm->hosts[host];
>>>>>>>
>>>>>>> Even though no mailbox is specified in any upstream dts for this 0th host I
>>>>>>> didn't want the bindings to restrict that, that's why in the first example
>>>>>>> there's an empty element (<0>) for the 0th smsm host
>>>>>>>
>>>>>>>> Anyway, the question is if you need to know that some
>>>>>>>> mailbox is missing. But then it is weird to name them "ipc-1" etc.
>>>>>>>
>>>>>>> In either case we'd just query the mbox (either by name or index) and then
>>>>>>> see if it's there? Not quite sure I understand the sentence..
>>>>>>> Pretty sure either binding would work the same way.
>>>>>>
>>>>>> The question is: does the driver care only about having some mailboxes
>>>>>> or the driver cares about each specific mailbox? IOW, is skipping ipc-0
>>>>>> important for the driver?
>>>>>
>>>>> There's nothing special from driver side about any mailbox. Some SoCs have
>>>>> a mailbox for e.g. hosts 1&2&3, some have only 1&3, and apq8064 even has
>>>>> 1&2&3&4.
>>>>>
>>>>> And if the driver doesn't find a mailbox for a host, it just ignores it
>>>>> but then of course it can't 'ring' the mailbox for that host when necessary.
>>>>>
>>>>> Not sure how much more I can add here, to be fair I barely understand what
>>>>> this driver is doing myself apart from the obvious.
>>>>
>>>> From what you said, it looks like it is enough to just list mailboxes,
>>>> e.g. for ipc-1, ipc-2 and ipc-4 (so no ipc-0 and ipc-3):
>>>
>>> No, for sure we need also the possibility to list ipc-3.
>>
>> ? You can list it, what's the problem>
> 
> Maybe we're talking past each other...
> 
> You asked why this wouldn't work:
> 
>   e.g. for ipc-1, ipc-2 and ipc-4 (so no ipc-0 and ipc-3):
>   mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
> 
> How would we know that the 3rd mailbox (&apcs 19) is for the 4th host
> (previous ipc-4)?
> 
> 1. If we use mboxes with indexes we'd need to have <0> values for
> "smsm hosts" where we don't have a mailbox for - this is at least
> for the 2nd smsm host (qcom,ipc-2) for a bunch of SoCs.
> 
> 2. If we use mboxes with mbox-names then we could skip that since we
> can directly specify which "smsm host" a given mailbox is for.
> 
> My only question really is whether 1. or 2. is a better idea.
> 
> Is this clearer now or still not?


So again, does the driver care about missing entry? If so, why?

Best regards,
Krzysztof

Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Luca Weiss]

On Samstag, 25. Mai 2024 18:47:08 MESZ Krzysztof Kozlowski wrote:
> On 24/05/2024 19:55, Luca Weiss wrote:
> > On Donnerstag, 23. Mai 2024 08:19:11 MESZ Krzysztof Kozlowski wrote:
> >> On 23/05/2024 08:16, Luca Weiss wrote:
> >>> On Donnerstag, 23. Mai 2024 08:02:13 MESZ Krzysztof Kozlowski wrote:
> >>>> On 22/05/2024 19:34, Luca Weiss wrote:
> >>>>> On Mittwoch, 22. Mai 2024 08:49:43 MESZ Krzysztof Kozlowski wrote:
> >>>>>> On 21/05/2024 22:35, Luca Weiss wrote:
> >>>>>>> On Dienstag, 21. Mai 2024 10:58:07 MESZ Krzysztof Kozlowski wrote:
> >>>>>>>> On 20/05/2024 17:11, Luca Weiss wrote:
> >>>>>>>>> Hi Krzysztof
> >>>>>>>>>
> >>>>>>>>> Ack, sounds good.
> >>>>>>>>>
> >>>>>>>>> Maybe also from you, any opinion between these two binding styles?
> >>>>>>>>>
> >>>>>>>>> So first using index of mboxes for the numbering, where for the known
> >>>>>>>>> usages the first element (and sometimes the 3rd - ipc-2) are empty <>.
> >>>>>>>>>
> >>>>>>>>> The second variant is using mbox-names to get the correct channel-mbox
> >>>>>>>>> mapping.
> >>>>>>>>>
> >>>>>>>>> -               qcom,ipc-1 = <&apcs 8 13>;
> >>>>>>>>> -               qcom,ipc-2 = <&apcs 8 9>;
> >>>>>>>>> -               qcom,ipc-3 = <&apcs 8 19>;
> >>>>>>>>> +               mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>;
> >>>>>>>>>
> >>>>>>>>> vs.
> >>>>>>>>>
> >>>>>>>>> -               qcom,ipc-1 = <&apcs 8 13>;
> >>>>>>>>> -               qcom,ipc-2 = <&apcs 8 9>;
> >>>>>>>>> -               qcom,ipc-3 = <&apcs 8 19>;
> >>>>>>>>> +               mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
> >>>>>>>>> +               mbox-names = "ipc-1", "ipc-2", "ipc-3";
> >>>>>>>>
> >>>>>>>> Sorry, don't get, ipc-1 is the first mailbox, so why would there be <0>
> >>>>>>>> in first case?
> >>>>>>>
> >>>>>>> Actually not, ipc-0 would be permissible by the driver, used for the 0th host
> >>>>>>>
> >>>>>>> e.g. from:
> >>>>>>>
> >>>>>>> 	/* Iterate over all hosts to check whom wants a kick */
> >>>>>>> 	for (host = 0; host < smsm->num_hosts; host++) {
> >>>>>>> 		hostp = &smsm->hosts[host];
> >>>>>>>
> >>>>>>> Even though no mailbox is specified in any upstream dts for this 0th host I
> >>>>>>> didn't want the bindings to restrict that, that's why in the first example
> >>>>>>> there's an empty element (<0>) for the 0th smsm host
> >>>>>>>
> >>>>>>>> Anyway, the question is if you need to know that some
> >>>>>>>> mailbox is missing. But then it is weird to name them "ipc-1" etc.
> >>>>>>>
> >>>>>>> In either case we'd just query the mbox (either by name or index) and then
> >>>>>>> see if it's there? Not quite sure I understand the sentence..
> >>>>>>> Pretty sure either binding would work the same way.
> >>>>>>
> >>>>>> The question is: does the driver care only about having some mailboxes
> >>>>>> or the driver cares about each specific mailbox? IOW, is skipping ipc-0
> >>>>>> important for the driver?
> >>>>>
> >>>>> There's nothing special from driver side about any mailbox. Some SoCs have
> >>>>> a mailbox for e.g. hosts 1&2&3, some have only 1&3, and apq8064 even has
> >>>>> 1&2&3&4.
> >>>>>
> >>>>> And if the driver doesn't find a mailbox for a host, it just ignores it
> >>>>> but then of course it can't 'ring' the mailbox for that host when necessary.
> >>>>>
> >>>>> Not sure how much more I can add here, to be fair I barely understand what
> >>>>> this driver is doing myself apart from the obvious.
> >>>>
> >>>> From what you said, it looks like it is enough to just list mailboxes,
> >>>> e.g. for ipc-1, ipc-2 and ipc-4 (so no ipc-0 and ipc-3):
> >>>
> >>> No, for sure we need also the possibility to list ipc-3.
> >>
> >> ? You can list it, what's the problem>
> > 
> > Maybe we're talking past each other...
> > 
> > You asked why this wouldn't work:
> > 
> >   e.g. for ipc-1, ipc-2 and ipc-4 (so no ipc-0 and ipc-3):
> >   mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
> > 
> > How would we know that the 3rd mailbox (&apcs 19) is for the 4th host
> > (previous ipc-4)?
> > 
> > 1. If we use mboxes with indexes we'd need to have <0> values for
> > "smsm hosts" where we don't have a mailbox for - this is at least
> > for the 2nd smsm host (qcom,ipc-2) for a bunch of SoCs.
> > 
> > 2. If we use mboxes with mbox-names then we could skip that since we
> > can directly specify which "smsm host" a given mailbox is for.
> > 
> > My only question really is whether 1. or 2. is a better idea.
> > 
> > Is this clearer now or still not?
> 
> 
> So again, does the driver care about missing entry? If so, why?

What do you mean with "care"?

I didn't change any behavior to what's happening now, if e.g. qcom,ipc-3
is not set right now then the driver is okay with that and just won't
ring the mailbox for that smsm host.

The behavior will be the same with mbox, if a mbox for e.g. the 3rd smsm
host is not set, the driver is okay with that but then of course won't do
anything for that host.

See the driver patch for details, or is something unclear there?

Regards
Luca

> 
> Best regards,
> Krzysztof
> 
> 

[PATCH RFC 2/2] soc: qcom: smsm: Support using mailbox interface

[Luca Weiss]

Add support for using the mbox interface instead of manually writing to
the syscon. With this change the driver will attempt to get the mailbox
first, and if that fails it will fall back to the existing way of using
qcom,ipc-* properties and converting to syscon.

Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
---
 drivers/soc/qcom/smsm.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 50 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/qcom/smsm.c b/drivers/soc/qcom/smsm.c
index e7c7e9a640a6..ffe78ae34386 100644
--- a/drivers/soc/qcom/smsm.c
+++ b/drivers/soc/qcom/smsm.c
@@ -5,6 +5,7 @@
  */
 
 #include <linux/interrupt.h>
+#include <linux/mailbox_client.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of_irq.h>
@@ -71,6 +72,7 @@ struct smsm_host;
  * @lock:	spinlock for read-modify-write of the outgoing state
  * @entries:	context for each of the entries
  * @hosts:	context for each of the hosts
+ * @mbox_client: mailbox client handle
  */
 struct qcom_smsm {
 	struct device *dev;
@@ -88,6 +90,8 @@ struct qcom_smsm {
 
 	struct smsm_entry *entries;
 	struct smsm_host *hosts;
+
+	struct mbox_client mbox_client;
 };
 
 /**
@@ -120,11 +124,14 @@ struct smsm_entry {
  * @ipc_regmap:	regmap for outgoing interrupt
  * @ipc_offset:	offset in @ipc_regmap for outgoing interrupt
  * @ipc_bit:	bit in @ipc_regmap + @ipc_offset for outgoing interrupt
+ * @mbox_chan:	apcs ipc mailbox channel handle
  */
 struct smsm_host {
 	struct regmap *ipc_regmap;
 	int ipc_offset;
 	int ipc_bit;
+
+	struct mbox_chan *mbox_chan;
 };
 
 /**
@@ -172,7 +179,13 @@ static int smsm_update_bits(void *data, u32 mask, u32 value)
 		hostp = &smsm->hosts[host];
 
 		val = readl(smsm->subscription + host);
-		if (val & changes && hostp->ipc_regmap) {
+		if (!(val & changes))
+			continue;
+
+		if (hostp->mbox_chan) {
+			mbox_send_message(hostp->mbox_chan, NULL);
+			mbox_client_txdone(hostp->mbox_chan, 0);
+		} else if (hostp->ipc_regmap) {
 			regmap_write(hostp->ipc_regmap,
 				     hostp->ipc_offset,
 				     BIT(hostp->ipc_bit));
@@ -352,6 +365,28 @@ static const struct irq_domain_ops smsm_irq_ops = {
 	.xlate = irq_domain_xlate_twocell,
 };
 
+/**
+ * smsm_parse_mbox() - requests an mbox channel
+ * @smsm:	smsm driver context
+ * @host_id:	index of the remote host to be resolved
+ *
+ * Requests the desired channel using the mbox interface which is needed for
+ * sending the outgoing interrupts to a remove hosts - identified by @host_id.
+ */
+static int smsm_parse_mbox(struct qcom_smsm *smsm, unsigned int host_id)
+{
+	struct smsm_host *host = &smsm->hosts[host_id];
+	int ret = 0;
+
+	host->mbox_chan = mbox_request_channel(&smsm->mbox_client, host_id);
+	if (IS_ERR(host->mbox_chan)) {
+		ret = PTR_ERR(host->mbox_chan);
+		host->mbox_chan = NULL;
+	}
+
+	return ret;
+}
+
 /**
  * smsm_parse_ipc() - parses a qcom,ipc-%d device tree property
  * @smsm:	smsm driver context
@@ -521,8 +556,16 @@ static int qcom_smsm_probe(struct platform_device *pdev)
 			     "qcom,local-host",
 			     &smsm->local_host);
 
+	smsm->mbox_client.dev = &pdev->dev;
+	smsm->mbox_client.knows_txdone = true;
+
 	/* Parse the host properties */
 	for (id = 0; id < smsm->num_hosts; id++) {
+		/* Try using mbox interface first, otherwise fall back to syscon */
+		ret = smsm_parse_mbox(smsm, id);
+		if (!ret)
+			continue;
+
 		ret = smsm_parse_ipc(smsm, id);
 		if (ret < 0)
 			goto out_put;
@@ -609,6 +652,9 @@ static int qcom_smsm_probe(struct platform_device *pdev)
 
 	qcom_smem_state_unregister(smsm->state);
 out_put:
+	for (id = 0; id < smsm->num_hosts; id++)
+		mbox_free_channel(smsm->hosts[id].mbox_chan);
+
 	of_node_put(local_node);
 	return ret;
 }
@@ -622,6 +668,9 @@ static void qcom_smsm_remove(struct platform_device *pdev)
 		if (smsm->entries[id].domain)
 			irq_domain_remove(smsm->entries[id].domain);
 
+	for (id = 0; id < smsm->num_hosts; id++)
+		mbox_free_channel(smsm->hosts[id].mbox_chan);
+
 	qcom_smem_state_unregister(smsm->state);
 }
 

-- 
2.44.0

Re: [PATCH RFC 2/2] soc: qcom: smsm: Support using mailbox interface

[Konrad Dybcio]

On 4/24/24 19:21, Luca Weiss wrote:
> Add support for using the mbox interface instead of manually writing to
> the syscon. With this change the driver will attempt to get the mailbox
> first, and if that fails it will fall back to the existing way of using
> qcom,ipc-* properties and converting to syscon.
> 
> Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
> ---

Looks good!

Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Konrad