Re: [PATCH v4 1/2] dt-bindings: Add bindings for BrcmSTB SCMI mailbox driver
On Thu, Nov 05, 2020 at 01:57:07PM -0500, Jim Quinlan wrote:
> On Thu, Nov 5, 2020 at 1:27 PM Sudeep Holla wrote:
> >
> > On Thu, Nov 05, 2020 at 10:28:25AM -0500, Jim Quinlan wrote:
> > > On Thu, Nov 5, 2020 at 10:13 AM Rob Herring wrote:
> > > >
> > > > On Wed, Nov 4, 2020 at 4:04 PM Jim Quinlan
> > > > wrote:
> > > > >
> > > > > On Wed, Nov 4, 2020 at 4:50 PM Rob Herring wrote:
> > > > > >
> > > > > > On Thu, Oct 29, 2020 at 03:59:06PM -0400, Jim Quinlan wrote:
> > > > > > > Bindings are added. Only one interrupt is needed because
> > > > > > > we do not yet employ the SCMI p2a channel.
> > > > > >
> > > > > > I still don't understand what this is. To repeat from v1: I thought
> > > > > > SCMI
> > > > > > was a mailbox consumer, not provider?
> > > > >
> > > > > Hi Rob,
> > > > >
> > > > > I'm not sure where I am implying that SCMI is a mailbox provider?
> > > > > Should I not mention "SCMI" in the subject line?
> > > > >
> > > > > This is just a mailbox driver, "consumed" by SCMI.Our SCMI DT node
> > > > > looks like this:
> > > > >
> > > > > brcm_scmi_mailbox: brcm_scmi_mailbox@0 {
> > > > > #mbox-cells = <1>;
> > > > > compatible = "brcm,brcmstb-mbox";
> > > > > };
> > > > >
> > > > > brcm_scmi@0 {
> > > > > compatible = "arm,scmi";
> > > > > mboxes = <_scmi_mailbox 0>;;
> > > > > mbox-names = "tx";
> > > > > shmem = <>;
> > > > > /* ... */
> > > > > };
> > > >
> > > > Okay, that makes more sense. Though it seems like this is just adding
> > > > a pointless level of indirection to turn an interrupt into a mailbox.
> > > > There's nothing more to 'the mailbox' is there?
> > >
> > > Correct. Although you can see that it uses both interrupts and SMC
> > > calls to get the job done.
> > >
> >
> > I was against having 2 separate solutions and would have raised my concern
> > again. As I mentioned earlier, either extend what we have or move the
> > existing SMC solution into this mailbox driver. Having 2 different solution
> > for this just because you have extra interrupt to deal with is definite
> > NACK from me as I had previously mentioned.
> >
> > > > So why not either
> > > > allow SCMI to have an interrupt directly
> > > Not sure here -- perhaps the SCMI folks have an answer?
> > >
> >
> > I did ask why can't you extend the existing SCMI/SMC binding to add this
> > as optional feature ?
> Hi Sudeep,
>
> Looking at the email you said, "In that case any reason why you can't
> reuse the existing smc transport for SCMI." , and I replied with the
> reason. I did not interpret your statement above as what you are
> clearly saying now: "either extend what we have or move the existing
> SMC solution into this mailbox driver. "
>
No, you are right. I didn't mention that explicitly. I wanted to, but
thought I will wait until this driver got traction to ask you to merge
them. Sorry for that. Anyways I am against having existing solution and
a mailbox for SMC, they need to be merged at any cost. Where the final
solution will be doesn't matter much to me, I am fine either way.
--
Regards,
Sudeep
Re: [PATCH v4 1/2] dt-bindings: Add bindings for BrcmSTB SCMI mailbox driver
On Thu, Nov 5, 2020 at 1:27 PM Sudeep Holla wrote:
>
> On Thu, Nov 05, 2020 at 10:28:25AM -0500, Jim Quinlan wrote:
> > On Thu, Nov 5, 2020 at 10:13 AM Rob Herring wrote:
> > >
> > > On Wed, Nov 4, 2020 at 4:04 PM Jim Quinlan
> > > wrote:
> > > >
> > > > On Wed, Nov 4, 2020 at 4:50 PM Rob Herring wrote:
> > > > >
> > > > > On Thu, Oct 29, 2020 at 03:59:06PM -0400, Jim Quinlan wrote:
> > > > > > Bindings are added. Only one interrupt is needed because
> > > > > > we do not yet employ the SCMI p2a channel.
> > > > >
> > > > > I still don't understand what this is. To repeat from v1: I thought
> > > > > SCMI
> > > > > was a mailbox consumer, not provider?
> > > >
> > > > Hi Rob,
> > > >
> > > > I'm not sure where I am implying that SCMI is a mailbox provider?
> > > > Should I not mention "SCMI" in the subject line?
> > > >
> > > > This is just a mailbox driver, "consumed" by SCMI.Our SCMI DT node
> > > > looks like this:
> > > >
> > > > brcm_scmi_mailbox: brcm_scmi_mailbox@0 {
> > > > #mbox-cells = <1>;
> > > > compatible = "brcm,brcmstb-mbox";
> > > > };
> > > >
> > > > brcm_scmi@0 {
> > > > compatible = "arm,scmi";
> > > > mboxes = <_scmi_mailbox 0>;;
> > > > mbox-names = "tx";
> > > > shmem = <>;
> > > > /* ... */
> > > > };
> > >
> > > Okay, that makes more sense. Though it seems like this is just adding
> > > a pointless level of indirection to turn an interrupt into a mailbox.
> > > There's nothing more to 'the mailbox' is there?
> >
> > Correct. Although you can see that it uses both interrupts and SMC
> > calls to get the job done.
> >
>
> I was against having 2 separate solutions and would have raised my concern
> again. As I mentioned earlier, either extend what we have or move the
> existing SMC solution into this mailbox driver. Having 2 different solution
> for this just because you have extra interrupt to deal with is definite
> NACK from me as I had previously mentioned.
>
> > > So why not either
> > > allow SCMI to have an interrupt directly
> > Not sure here -- perhaps the SCMI folks have an answer?
> >
>
> I did ask why can't you extend the existing SCMI/SMC binding to add this
> as optional feature ?
Hi Sudeep,
Looking at the email you said, "In that case any reason why you can't
reuse the existing smc transport for SCMI." , and I replied with the
reason. I did not interpret your statement above as what you are
clearly saying now: "either extend what we have or move the existing
SMC solution into this mailbox driver. "
Fair enough, I will look into this.
Regards,
Jim
>
> > > or have a generic irq mailbox driver?
>
> Fine with this too.
>
> > The SCMI implementation doesn't offer a generic irq mailbox driver
> > AFAICT. The SCMI folks recently provided an "smc transport" driver
> > in "drivers/firmware/arm_scmi/smc.c" -- it is close to what we need
> > but is missing interrupts.
>
> IIRC, you were using SGIs and it can't be represented and use today as
> is ? Am I missing something or anything has changed ?
>
> --
> Regards,
> Sudeep
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Re: [PATCH v4 1/2] dt-bindings: Add bindings for BrcmSTB SCMI mailbox driver
On Thu, Nov 05, 2020 at 10:28:25AM -0500, Jim Quinlan wrote:
> On Thu, Nov 5, 2020 at 10:13 AM Rob Herring wrote:
> >
> > On Wed, Nov 4, 2020 at 4:04 PM Jim Quinlan
> > wrote:
> > >
> > > On Wed, Nov 4, 2020 at 4:50 PM Rob Herring wrote:
> > > >
> > > > On Thu, Oct 29, 2020 at 03:59:06PM -0400, Jim Quinlan wrote:
> > > > > Bindings are added. Only one interrupt is needed because
> > > > > we do not yet employ the SCMI p2a channel.
> > > >
> > > > I still don't understand what this is. To repeat from v1: I thought SCMI
> > > > was a mailbox consumer, not provider?
> > >
> > > Hi Rob,
> > >
> > > I'm not sure where I am implying that SCMI is a mailbox provider?
> > > Should I not mention "SCMI" in the subject line?
> > >
> > > This is just a mailbox driver, "consumed" by SCMI.Our SCMI DT node
> > > looks like this:
> > >
> > > brcm_scmi_mailbox: brcm_scmi_mailbox@0 {
> > > #mbox-cells = <1>;
> > > compatible = "brcm,brcmstb-mbox";
> > > };
> > >
> > > brcm_scmi@0 {
> > > compatible = "arm,scmi";
> > > mboxes = <_scmi_mailbox 0>;;
> > > mbox-names = "tx";
> > > shmem = <>;
> > > /* ... */
> > > };
> >
> > Okay, that makes more sense. Though it seems like this is just adding
> > a pointless level of indirection to turn an interrupt into a mailbox.
> > There's nothing more to 'the mailbox' is there?
>
> Correct. Although you can see that it uses both interrupts and SMC
> calls to get the job done.
>
I was against having 2 separate solutions and would have raised my concern
again. As I mentioned earlier, either extend what we have or move the
existing SMC solution into this mailbox driver. Having 2 different solution
for this just because you have extra interrupt to deal with is definite
NACK from me as I had previously mentioned.
> > So why not either
> > allow SCMI to have an interrupt directly
> Not sure here -- perhaps the SCMI folks have an answer?
>
I did ask why can't you extend the existing SCMI/SMC binding to add this
as optional feature ?
> > or have a generic irq mailbox driver?
Fine with this too.
> The SCMI implementation doesn't offer a generic irq mailbox driver
> AFAICT. The SCMI folks recently provided an "smc transport" driver
> in "drivers/firmware/arm_scmi/smc.c" -- it is close to what we need
> but is missing interrupts.
IIRC, you were using SGIs and it can't be represented and use today as
is ? Am I missing something or anything has changed ?
--
Regards,
Sudeep
Re: [PATCH v4 1/2] dt-bindings: Add bindings for BrcmSTB SCMI mailbox driver
On Thu, Nov 5, 2020 at 10:13 AM Rob Herring wrote:
>
> On Wed, Nov 4, 2020 at 4:04 PM Jim Quinlan wrote:
> >
> > On Wed, Nov 4, 2020 at 4:50 PM Rob Herring wrote:
> > >
> > > On Thu, Oct 29, 2020 at 03:59:06PM -0400, Jim Quinlan wrote:
> > > > Bindings are added. Only one interrupt is needed because
> > > > we do not yet employ the SCMI p2a channel.
> > >
> > > I still don't understand what this is. To repeat from v1: I thought SCMI
> > > was a mailbox consumer, not provider?
> >
> > Hi Rob,
> >
> > I'm not sure where I am implying that SCMI is a mailbox provider?
> > Should I not mention "SCMI" in the subject line?
> >
> > This is just a mailbox driver, "consumed" by SCMI.Our SCMI DT node
> > looks like this:
> >
> > brcm_scmi_mailbox: brcm_scmi_mailbox@0 {
> > #mbox-cells = <1>;
> > compatible = "brcm,brcmstb-mbox";
> > };
> >
> > brcm_scmi@0 {
> > compatible = "arm,scmi";
> > mboxes = <_scmi_mailbox 0>;;
> > mbox-names = "tx";
> > shmem = <>;
> > /* ... */
> > };
>
> Okay, that makes more sense. Though it seems like this is just adding
> a pointless level of indirection to turn an interrupt into a mailbox.
> There's nothing more to 'the mailbox' is there?
Correct. Although you can see that it uses both interrupts and SMC
calls to get the job done.
> So why not either
> allow SCMI to have an interrupt directly
Not sure here -- perhaps the SCMI folks have an answer?
> or have a generic irq mailbox
> driver?
The SCMI implementation doesn't offer a generic irq mailbox driver
AFAICT. The SCMI folks recently provided an "smc transport" driver
in "drivers/firmware/arm_scmi/smc.c" -- it is close to what we need
but is missing interrupts.
Regards,
Jim Quinlan
Broadcom STB
>
> Rob
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Re: [PATCH v4 1/2] dt-bindings: Add bindings for BrcmSTB SCMI mailbox driver
On Wed, Nov 4, 2020 at 4:04 PM Jim Quinlan wrote:
>
> On Wed, Nov 4, 2020 at 4:50 PM Rob Herring wrote:
> >
> > On Thu, Oct 29, 2020 at 03:59:06PM -0400, Jim Quinlan wrote:
> > > Bindings are added. Only one interrupt is needed because
> > > we do not yet employ the SCMI p2a channel.
> >
> > I still don't understand what this is. To repeat from v1: I thought SCMI
> > was a mailbox consumer, not provider?
>
> Hi Rob,
>
> I'm not sure where I am implying that SCMI is a mailbox provider?
> Should I not mention "SCMI" in the subject line?
>
> This is just a mailbox driver, "consumed" by SCMI.Our SCMI DT node
> looks like this:
>
> brcm_scmi_mailbox: brcm_scmi_mailbox@0 {
> #mbox-cells = <1>;
> compatible = "brcm,brcmstb-mbox";
> };
>
> brcm_scmi@0 {
> compatible = "arm,scmi";
> mboxes = <_scmi_mailbox 0>;;
> mbox-names = "tx";
> shmem = <>;
> /* ... */
> };
Okay, that makes more sense. Though it seems like this is just adding
a pointless level of indirection to turn an interrupt into a mailbox.
There's nothing more to 'the mailbox' is there? So why not either
allow SCMI to have an interrupt directly or have a generic irq mailbox
driver?
Rob
Re: [PATCH v4 1/2] dt-bindings: Add bindings for BrcmSTB SCMI mailbox driver
On Wed, Nov 4, 2020 at 4:50 PM Rob Herring wrote:
>
> On Thu, Oct 29, 2020 at 03:59:06PM -0400, Jim Quinlan wrote:
> > Bindings are added. Only one interrupt is needed because
> > we do not yet employ the SCMI p2a channel.
>
> I still don't understand what this is. To repeat from v1: I thought SCMI
> was a mailbox consumer, not provider?
Hi Rob,
I'm not sure where I am implying that SCMI is a mailbox provider?
Should I not mention "SCMI" in the subject line?
This is just a mailbox driver, "consumed" by SCMI.Our SCMI DT node
looks like this:
brcm_scmi_mailbox: brcm_scmi_mailbox@0 {
#mbox-cells = <1>;
compatible = "brcm,brcmstb-mbox";
};
brcm_scmi@0 {
compatible = "arm,scmi";
mboxes = <_scmi_mailbox 0>;;
mbox-names = "tx";
shmem = <>;
/* ... */
};
Please advise,
Jim Quinlan
Broadcom STB
>
> >
> > Signed-off-by: Jim Quinlan
> > ---
> > .../bindings/mailbox/brcm,brcmstb-mbox.yaml | 39 +++
> > 1 file changed, 39 insertions(+)
> > create mode 100644
> > Documentation/devicetree/bindings/mailbox/brcm,brcmstb-mbox.yaml
> >
> > diff --git
> > a/Documentation/devicetree/bindings/mailbox/brcm,brcmstb-mbox.yaml
> > b/Documentation/devicetree/bindings/mailbox/brcm,brcmstb-mbox.yaml
> > new file mode 100644
> > index ..797c0cc609a3
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mailbox/brcm,brcmstb-mbox.yaml
> > @@ -0,0 +1,39 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$schema: "http://devicetree.org/meta-schemas/core.yaml#;
> > +$id: http://devicetree.org/schemas/mailbox/brcm,brcmstb-mbox.yaml#
> > +
> > +title: Broadcom STB mailbox driver bindings
> > +
> > +maintainers:
> > + - Jim Quinlan
> > +
> > +properties:
> > + compatible:
> > +enum:
> > + - brcm,brcmstb-mbox
> > +
> > + interrupts:
> > +items:
> > + - description: a2p return interrupt, indicates SCMI msg completion.
> > +
> > + "#mbox-cells":
> > +const: 1
> > +
> > +required:
> > + - compatible
> > + - interrupts
> > + - "#mbox-cells"
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > + - |
> > +#include
> > +mailbox {
> > + compatible = "brcm,brcmstb-mailbox";
> > + #mbox-cells = <1>;
> > + interrupts = ;
> > +};
> > +...
> > --
> > 2.17.1
> >
>
>
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Re: [PATCH v4 1/2] dt-bindings: Add bindings for BrcmSTB SCMI mailbox driver
On Thu, Oct 29, 2020 at 03:59:06PM -0400, Jim Quinlan wrote:
> Bindings are added. Only one interrupt is needed because
> we do not yet employ the SCMI p2a channel.
I still don't understand what this is. To repeat from v1: I thought SCMI
was a mailbox consumer, not provider?
>
> Signed-off-by: Jim Quinlan
> ---
> .../bindings/mailbox/brcm,brcmstb-mbox.yaml | 39 +++
> 1 file changed, 39 insertions(+)
> create mode 100644
> Documentation/devicetree/bindings/mailbox/brcm,brcmstb-mbox.yaml
>
> diff --git a/Documentation/devicetree/bindings/mailbox/brcm,brcmstb-mbox.yaml
> b/Documentation/devicetree/bindings/mailbox/brcm,brcmstb-mbox.yaml
> new file mode 100644
> index ..797c0cc609a3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/brcm,brcmstb-mbox.yaml
> @@ -0,0 +1,39 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#;
> +$id: http://devicetree.org/schemas/mailbox/brcm,brcmstb-mbox.yaml#
> +
> +title: Broadcom STB mailbox driver bindings
> +
> +maintainers:
> + - Jim Quinlan
> +
> +properties:
> + compatible:
> +enum:
> + - brcm,brcmstb-mbox
> +
> + interrupts:
> +items:
> + - description: a2p return interrupt, indicates SCMI msg completion.
> +
> + "#mbox-cells":
> +const: 1
> +
> +required:
> + - compatible
> + - interrupts
> + - "#mbox-cells"
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> +#include
> +mailbox {
> + compatible = "brcm,brcmstb-mailbox";
> + #mbox-cells = <1>;
> + interrupts = ;
> +};
> +...
> --
> 2.17.1
>
[PATCH v4 1/2] dt-bindings: Add bindings for BrcmSTB SCMI mailbox driver
Bindings are added. Only one interrupt is needed because
we do not yet employ the SCMI p2a channel.
Signed-off-by: Jim Quinlan
---
.../bindings/mailbox/brcm,brcmstb-mbox.yaml | 39 +++
1 file changed, 39 insertions(+)
create mode 100644
Documentation/devicetree/bindings/mailbox/brcm,brcmstb-mbox.yaml
diff --git a/Documentation/devicetree/bindings/mailbox/brcm,brcmstb-mbox.yaml
b/Documentation/devicetree/bindings/mailbox/brcm,brcmstb-mbox.yaml
new file mode 100644
index ..797c0cc609a3
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/brcm,brcmstb-mbox.yaml
@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$schema: "http://devicetree.org/meta-schemas/core.yaml#;
+$id: http://devicetree.org/schemas/mailbox/brcm,brcmstb-mbox.yaml#
+
+title: Broadcom STB mailbox driver bindings
+
+maintainers:
+ - Jim Quinlan
+
+properties:
+ compatible:
+enum:
+ - brcm,brcmstb-mbox
+
+ interrupts:
+items:
+ - description: a2p return interrupt, indicates SCMI msg completion.
+
+ "#mbox-cells":
+const: 1
+
+required:
+ - compatible
+ - interrupts
+ - "#mbox-cells"
+
+additionalProperties: false
+
+examples:
+ - |
+#include
+mailbox {
+ compatible = "brcm,brcmstb-mailbox";
+ #mbox-cells = <1>;
+ interrupts = ;
+};
+...
--
2.17.1
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