[PATCH V3 1/2] dt-bindings: mailbox : arm,mhu: Convert to Json-schema

[PATCH V3 1/2] dt-bindings: mailbox : arm,mhu: Convert to Json-schema

[Viresh Kumar]

Convert the DT binding over to Json-schema.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
V3: New patch.

 .../devicetree/bindings/mailbox/arm,mhu.yaml  | 86 +++++++++++++++++++
 .../devicetree/bindings/mailbox/arm-mhu.txt   | 43 ----------
 2 files changed, 86 insertions(+), 43 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
 delete mode 100644 Documentation/devicetree/bindings/mailbox/arm-mhu.txt

diff --git a/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml b/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
new file mode 100644
index 000000000000..4e840cedb2e4
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
@@ -0,0 +1,86 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/arm,mhu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ARM MHU Mailbox Controller
+
+maintainers:
+  - Jassi Brar <jaswinder.singh@linaro.org>
+
+description: |
+  The ARM's Message-Handling-Unit (MHU) is a mailbox controller that has 3
+  independent channels/links to communicate with remote processor(s).  MHU links
+  are hardwired on a platform. A link raises interrupt for any received data.
+  However, there is no specified way of knowing if the sent data has been read
+  by the remote. This driver assumes the sender polls STAT register and the
+  remote clears it after having read the data.  The last channel is specified to
+  be a 'Secure' resource, hence can't be used by Linux running NS.
+
+# We need a select here so we don't match all nodes with 'arm,primecell'
+select:
+  properties:
+    compatible:
+      contains:
+        const: arm,mhu
+  required:
+    - compatible
+
+properties:
+  compatible:
+    items:
+      - const: arm,mhu
+      - const: arm,primecell
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    description: |
+      Interrupt information corresponding to each of the 3 links of MHU,
+      low-priority non-secure, high-priority non-secure, and secure.
+    maxItems: 3
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: apb_pclk
+
+  '#mbox-cells':
+    description: Index of the channel.
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - '#mbox-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        mhuA: mailbox@2b1f0000 {
+            #mbox-cells = <1>;
+            compatible = "arm,mhu", "arm,primecell";
+            reg = <0 0x2b1f0000 0 0x1000>;
+            interrupts = <0 36 4>, /* LP-NonSecure */
+                         <0 35 4>, /* HP-NonSecure */
+                         <0 37 4>; /* Secure */
+            clocks = <&clock 0 2 1>;
+            clock-names = "apb_pclk";
+        };
+
+        mhu_client_scb: scb@2e000000 {
+            compatible = "fujitsu,mb86s70-scb-1.0";
+            reg = <0 0x2e000000 0 0x4000>;
+            mboxes = <&mhuA 1>; /* HP-NonSecure */
+        };
+    };
diff --git a/Documentation/devicetree/bindings/mailbox/arm-mhu.txt b/Documentation/devicetree/bindings/mailbox/arm-mhu.txt
deleted file mode 100644
index 4971f03f0b33..000000000000
--- a/Documentation/devicetree/bindings/mailbox/arm-mhu.txt
+++ /dev/null
@@ -1,43 +0,0 @@
-ARM MHU Mailbox Driver
-======================
-
-The ARM's Message-Handling-Unit (MHU) is a mailbox controller that has
-3 independent channels/links to communicate with remote processor(s).
- MHU links are hardwired on a platform. A link raises interrupt for any
-received data. However, there is no specified way of knowing if the sent
-data has been read by the remote. This driver assumes the sender polls
-STAT register and the remote clears it after having read the data.
-The last channel is specified to be a 'Secure' resource, hence can't be
-used by Linux running NS.
-
-Mailbox Device Node:
-====================
-
-Required properties:
---------------------
-- compatible:		Shall be "arm,mhu" & "arm,primecell"
-- reg:			Contains the mailbox register address range (base
-			address and length)
-- #mbox-cells		Shall be 1 - the index of the channel needed.
-- interrupts:		Contains the interrupt information corresponding to
-			each of the 3 links of MHU.
-
-Example:
---------
-
-	mhu: mailbox@2b1f0000 {
-		#mbox-cells = <1>;
-		compatible = "arm,mhu", "arm,primecell";
-		reg = <0 0x2b1f0000 0x1000>;
-		interrupts = <0 36 4>, /* LP-NonSecure */
-			     <0 35 4>, /* HP-NonSecure */
-			     <0 37 4>; /* Secure */
-		clocks = <&clock 0 2 1>;
-		clock-names = "apb_pclk";
-	};
-
-	mhu_client: scb@2e000000 {
-		compatible = "fujitsu,mb86s70-scb-1.0";
-		reg = <0 0x2e000000 0x4000>;
-		mboxes = <&mhu 1>; /* HP-NonSecure */
-	};
-- 
2.25.0.rc1.19.g042ed3e048af

[PATCH V3 2/2] dt-bindings: mailbox: add doorbell support to ARM MHU

[Viresh Kumar]

From: Sudeep Holla <sudeep.holla@arm.com>

The ARM MHU's reference manual states following:

"The MHU drives the signal using a 32-bit register, with all 32 bits
logically ORed together. The MHU provides a set of registers to enable
software to set, clear, and check the status of each of the bits of this
register independently.  The use of 32 bits for each interrupt line
enables software to provide more information about the source of the
interrupt. For example, each bit of the register can be associated with
a type of event that can contribute to raising the interrupt."

This patch thus extends the MHU controller's DT binding to add support
for doorbell mode.

Though the same MHU hardware controller is used in the two modes, A new
compatible string is added here to represent the combination of the MHU
hardware and the firmware sitting on the other side (which expects each
bit to represent a different signal now).

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Co-developed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
V3: Update the json schema and fix number of interrupt lines.

 .../devicetree/bindings/mailbox/arm,mhu.yaml  | 60 +++++++++++++++++--
 1 file changed, 54 insertions(+), 6 deletions(-)

diff --git a/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml b/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
index 4e840cedb2e4..88980ba005a4 100644
--- a/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
+++ b/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
@@ -18,20 +18,40 @@ description: |
   remote clears it after having read the data.  The last channel is specified to
   be a 'Secure' resource, hence can't be used by Linux running NS.
 
+  The MHU hardware also allows operations in doorbell mode. The MHU drives the
+  interrupt signal using a 32-bit register, with all 32-bits logically ORed
+  together. It provides a set of registers to enable software to set, clear and
+  check the status of each of the bits of this register independently. The use
+  of 32 bits per interrupt line enables software to provide more information
+  about the source of the interrupt. For example, each bit of the register can
+  be associated with a type of event that can contribute to raising the
+  interrupt. Each of the 32-bits can be used as "doorbell" to alert the remote
+  processor.
+
 # We need a select here so we don't match all nodes with 'arm,primecell'
 select:
   properties:
     compatible:
       contains:
-        const: arm,mhu
+        enum:
+          - arm,mhu
+          - arm,mhu-doorbell
   required:
     - compatible
 
 properties:
   compatible:
-    items:
-      - const: arm,mhu
-      - const: arm,primecell
+    oneOf:
+      - description: Data transfer mode
+        items:
+          - const: arm,mhu
+          - const: arm,primecell
+
+      - description: Doorbell mode
+        items:
+          - const: arm,mhu-doorbell
+          - const: arm,primecell
+
 
   reg:
     maxItems: 1
@@ -50,8 +70,11 @@ description: |
       - const: apb_pclk
 
   '#mbox-cells':
-    description: Index of the channel.
-    const: 1
+    description: |
+      Set to 1 in data transfer mode and represents index of the channel.
+      Set to 2 in doorbell mode and represents index of the channel and doorbell
+      number.
+    enum: [ 1, 2 ]
 
 required:
   - compatible
@@ -62,6 +85,7 @@ description: |
 additionalProperties: false
 
 examples:
+  # Data transfer mode.
   - |
     soc {
         #address-cells = <2>;
@@ -84,3 +108,27 @@ additionalProperties: false
             mboxes = <&mhuA 1>; /* HP-NonSecure */
         };
     };
+
+  # Doorbell mode.
+  - |
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        mhuB: mailbox@2b2f0000 {
+            #mbox-cells = <2>;
+            compatible = "arm,mhu-doorbell", "arm,primecell";
+            reg = <0 0x2b2f0000 0 0x1000>;
+            interrupts = <0 36 4>, /* LP-NonSecure */
+                         <0 35 4>, /* HP-NonSecure */
+                         <0 37 4>; /* Secure */
+            clocks = <&clock 0 2 1>;
+            clock-names = "apb_pclk";
+        };
+
+        mhu_client_scpi: scpi@2f000000 {
+            compatible = "arm,scpi";
+            reg = <0 0x2f000000 0 0x200>;
+            mboxes = <&mhuB 1 4>; /* HP-NonSecure, 5th doorbell */
+        };
+    };
-- 
2.25.0.rc1.19.g042ed3e048af

Re: [PATCH V3 1/2] dt-bindings: mailbox : arm,mhu: Convert to Json-schema

[Rob Herring]

On Thu, Sep 10, 2020 at 03:25:18PM +0530, Viresh Kumar wrote:
> Convert the DT binding over to Json-schema.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
> V3: New patch.
> 
>  .../devicetree/bindings/mailbox/arm,mhu.yaml  | 86 +++++++++++++++++++
>  .../devicetree/bindings/mailbox/arm-mhu.txt   | 43 ----------
>  2 files changed, 86 insertions(+), 43 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
>  delete mode 100644 Documentation/devicetree/bindings/mailbox/arm-mhu.txt
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml b/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
> new file mode 100644
> index 000000000000..4e840cedb2e4
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
> @@ -0,0 +1,86 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mailbox/arm,mhu.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: ARM MHU Mailbox Controller
> +
> +maintainers:
> +  - Jassi Brar <jaswinder.singh@linaro.org>

Ideally, this should be someone familiar with the h/w, not the subsystem 
maintainer. Sudeep or you in this case?
 
> +
> +description: |
> +  The ARM's Message-Handling-Unit (MHU) is a mailbox controller that has 3
> +  independent channels/links to communicate with remote processor(s).  MHU links
> +  are hardwired on a platform. A link raises interrupt for any received data.
> +  However, there is no specified way of knowing if the sent data has been read
> +  by the remote. This driver assumes the sender polls STAT register and the
> +  remote clears it after having read the data.  The last channel is specified to
> +  be a 'Secure' resource, hence can't be used by Linux running NS.
> +
> +# We need a select here so we don't match all nodes with 'arm,primecell'
> +select:
> +  properties:
> +    compatible:
> +      contains:
> +        const: arm,mhu
> +  required:
> +    - compatible
> +
> +properties:
> +  compatible:
> +    items:
> +      - const: arm,mhu
> +      - const: arm,primecell
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    description: |
> +      Interrupt information corresponding to each of the 3 links of MHU,
> +      low-priority non-secure, high-priority non-secure, and secure.
> +    maxItems: 3

items:
  - description: low-priority non-secure
  - description: high-priority non-secure
  - description: Secure

> +
> +  clocks:
> +    maxItems: 1
> +
> +  clock-names:
> +    items:
> +      - const: apb_pclk
> +
> +  '#mbox-cells':
> +    description: Index of the channel.
> +    const: 1
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - '#mbox-cells'
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    soc {
> +        #address-cells = <2>;
> +        #size-cells = <2>;
> +
> +        mhuA: mailbox@2b1f0000 {
> +            #mbox-cells = <1>;
> +            compatible = "arm,mhu", "arm,primecell";
> +            reg = <0 0x2b1f0000 0 0x1000>;
> +            interrupts = <0 36 4>, /* LP-NonSecure */
> +                         <0 35 4>, /* HP-NonSecure */
> +                         <0 37 4>; /* Secure */
> +            clocks = <&clock 0 2 1>;
> +            clock-names = "apb_pclk";
> +        };
> +
> +        mhu_client_scb: scb@2e000000 {
> +            compatible = "fujitsu,mb86s70-scb-1.0";
> +            reg = <0 0x2e000000 0 0x4000>;
> +            mboxes = <&mhuA 1>; /* HP-NonSecure */
> +        };
> +    };
> diff --git a/Documentation/devicetree/bindings/mailbox/arm-mhu.txt b/Documentation/devicetree/bindings/mailbox/arm-mhu.txt
> deleted file mode 100644
> index 4971f03f0b33..000000000000
> --- a/Documentation/devicetree/bindings/mailbox/arm-mhu.txt
> +++ /dev/null
> @@ -1,43 +0,0 @@
> -ARM MHU Mailbox Driver
> -======================
> -
> -The ARM's Message-Handling-Unit (MHU) is a mailbox controller that has
> -3 independent channels/links to communicate with remote processor(s).
> - MHU links are hardwired on a platform. A link raises interrupt for any
> -received data. However, there is no specified way of knowing if the sent
> -data has been read by the remote. This driver assumes the sender polls
> -STAT register and the remote clears it after having read the data.
> -The last channel is specified to be a 'Secure' resource, hence can't be
> -used by Linux running NS.
> -
> -Mailbox Device Node:
> -====================
> -
> -Required properties:
> ---------------------
> -- compatible:		Shall be "arm,mhu" & "arm,primecell"
> -- reg:			Contains the mailbox register address range (base
> -			address and length)
> -- #mbox-cells		Shall be 1 - the index of the channel needed.
> -- interrupts:		Contains the interrupt information corresponding to
> -			each of the 3 links of MHU.
> -
> -Example:
> ---------
> -
> -	mhu: mailbox@2b1f0000 {
> -		#mbox-cells = <1>;
> -		compatible = "arm,mhu", "arm,primecell";
> -		reg = <0 0x2b1f0000 0x1000>;
> -		interrupts = <0 36 4>, /* LP-NonSecure */
> -			     <0 35 4>, /* HP-NonSecure */
> -			     <0 37 4>; /* Secure */
> -		clocks = <&clock 0 2 1>;
> -		clock-names = "apb_pclk";
> -	};
> -
> -	mhu_client: scb@2e000000 {
> -		compatible = "fujitsu,mb86s70-scb-1.0";
> -		reg = <0 0x2e000000 0x4000>;
> -		mboxes = <&mhu 1>; /* HP-NonSecure */
> -	};
> -- 
> 2.25.0.rc1.19.g042ed3e048af
> 

Re: [PATCH V3 1/2] dt-bindings: mailbox : arm,mhu: Convert to Json-schema

[Rob Herring]

On Thu, Sep 10, 2020 at 03:25:18PM +0530, Viresh Kumar wrote:
> Convert the DT binding over to Json-schema.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
> V3: New patch.
> 
>  .../devicetree/bindings/mailbox/arm,mhu.yaml  | 86 +++++++++++++++++++
>  .../devicetree/bindings/mailbox/arm-mhu.txt   | 43 ----------
>  2 files changed, 86 insertions(+), 43 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
>  delete mode 100644 Documentation/devicetree/bindings/mailbox/arm-mhu.txt
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml b/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
> new file mode 100644
> index 000000000000..4e840cedb2e4
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
> @@ -0,0 +1,86 @@
> +# SPDX-License-Identifier: GPL-2.0

Also, as Jassi/Linaro is the only author of the txt file, please dual 
license.

Rob

Re: [PATCH V3 2/2] dt-bindings: mailbox: add doorbell support to ARM MHU

[Rob Herring]

On Thu, 10 Sep 2020 15:25:19 +0530, Viresh Kumar wrote:
> From: Sudeep Holla <sudeep.holla@arm.com>
> 
> The ARM MHU's reference manual states following:
> 
> "The MHU drives the signal using a 32-bit register, with all 32 bits
> logically ORed together. The MHU provides a set of registers to enable
> software to set, clear, and check the status of each of the bits of this
> register independently.  The use of 32 bits for each interrupt line
> enables software to provide more information about the source of the
> interrupt. For example, each bit of the register can be associated with
> a type of event that can contribute to raising the interrupt."
> 
> This patch thus extends the MHU controller's DT binding to add support
> for doorbell mode.
> 
> Though the same MHU hardware controller is used in the two modes, A new
> compatible string is added here to represent the combination of the MHU
> hardware and the firmware sitting on the other side (which expects each
> bit to represent a different signal now).
> 
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> Co-developed-by: Viresh Kumar <viresh.kumar@linaro.org>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
> V3: Update the json schema and fix number of interrupt lines.
> 
>  .../devicetree/bindings/mailbox/arm,mhu.yaml  | 60 +++++++++++++++++--
>  1 file changed, 54 insertions(+), 6 deletions(-)
> 

Reviewed-by: Rob Herring <robh@kernel.org>

Re: [PATCH V3 1/2] dt-bindings: mailbox : arm,mhu: Convert to Json-schema

[Jassi Brar]

On Tue, Sep 15, 2020 at 2:35 PM Rob Herring <robh@kernel.org> wrote:
>
> On Thu, Sep 10, 2020 at 03:25:18PM +0530, Viresh Kumar wrote:
> > Convert the DT binding over to Json-schema.
> >
> > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> > ---
> > V3: New patch.
> >
> >  .../devicetree/bindings/mailbox/arm,mhu.yaml  | 86 +++++++++++++++++++
> >  .../devicetree/bindings/mailbox/arm-mhu.txt   | 43 ----------
> >  2 files changed, 86 insertions(+), 43 deletions(-)
> >  create mode 100644 Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
> >  delete mode 100644 Documentation/devicetree/bindings/mailbox/arm-mhu.txt
> >
> > diff --git a/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml b/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
> > new file mode 100644
> > index 000000000000..4e840cedb2e4
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
> > @@ -0,0 +1,86 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/mailbox/arm,mhu.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: ARM MHU Mailbox Controller
> > +
> > +maintainers:
> > +  - Jassi Brar <jaswinder.singh@linaro.org>
>
> Ideally, this should be someone familiar with the h/w, not the subsystem
> maintainer. Sudeep or you in this case?
>
If you are ok with the content of this file, maybe I am not as
unfamiliar with MHU as you think :D   I wrote the original doc/binding
that this yaml is translated from.
Maybe Viresh/Sudeep should be the maintainer of the mhu doorbell bindings ?

Re: [PATCH V3 1/2] dt-bindings: mailbox : arm,mhu: Convert to Json-schema

[Rob Herring]

On Tue, Sep 15, 2020 at 1:49 PM Jassi Brar <jassisinghbrar@gmail.com> wrote:
>
> On Tue, Sep 15, 2020 at 2:35 PM Rob Herring <robh@kernel.org> wrote:
> >
> > On Thu, Sep 10, 2020 at 03:25:18PM +0530, Viresh Kumar wrote:
> > > Convert the DT binding over to Json-schema.
> > >
> > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> > > ---
> > > V3: New patch.
> > >
> > >  .../devicetree/bindings/mailbox/arm,mhu.yaml  | 86 +++++++++++++++++++
> > >  .../devicetree/bindings/mailbox/arm-mhu.txt   | 43 ----------
> > >  2 files changed, 86 insertions(+), 43 deletions(-)
> > >  create mode 100644 Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
> > >  delete mode 100644 Documentation/devicetree/bindings/mailbox/arm-mhu.txt
> > >
> > > diff --git a/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml b/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
> > > new file mode 100644
> > > index 000000000000..4e840cedb2e4
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/mailbox/arm,mhu.yaml
> > > @@ -0,0 +1,86 @@
> > > +# SPDX-License-Identifier: GPL-2.0
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/mailbox/arm,mhu.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: ARM MHU Mailbox Controller
> > > +
> > > +maintainers:
> > > +  - Jassi Brar <jaswinder.singh@linaro.org>
> >
> > Ideally, this should be someone familiar with the h/w, not the subsystem
> > maintainer. Sudeep or you in this case?
> >
> If you are ok with the content of this file, maybe I am not as
> unfamiliar with MHU as you think :D   I wrote the original doc/binding
> that this yaml is translated from.

You're right, I'd already forgotten this comment when I checked for
licensing afterwards and saw you wrote it. It's just a common thing
I'm commenting on.

> Maybe Viresh/Sudeep should be the maintainer of the mhu doorbell bindings ?

I'm sure at this point, no one does. :)

Rob