[PATCH v4 1/2] dt-bindings: firmware: arm,scmi: Document arm,no-completion-irq property

[PATCH v4 1/2] dt-bindings: firmware: arm,scmi: Document arm,no-completion-irq property

[Marek Vasut]

Document new property arm,no-completion-irq . This optional property
is intended for hardware that does not generate completion interrupts
and can be used to unconditionally enable forced polling mode of
operation.

With this property set, such implementations which do not generate
interrupts can be interacted with, until they are fixed to generate
interrupts properly.

Note that, because the original base protocol exchange also requires
some sort of completion mechanism, it is not possible to query SCMI
itself for this property and it must be described in DT. While this
does look a bit like policy, the SCMI provider is part of the
hardware, hence DT.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Cristian Marussi <cristian.marussi@arm.com>
Cc: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: arm-scmi@vger.kernel.org
Cc: devicetree@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-renesas-soc@vger.kernel.org
---
V2: s@mean@&t and limit poll transport to mailbox/shmem only
V3: - Reformat the commit message, expand property description to
      explicitly spell out this is hardware description.
    - Rename property from arm,poll-transport to arm,no-completion-irq
V4: - Update first paragraph of commit message and property description
    - Add RB from Rob
---
 .../devicetree/bindings/firmware/arm,scmi.yaml         | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
index be817fd9cc34b..d06cca9273c48 100644
--- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
+++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
@@ -146,6 +146,13 @@ properties:
       this platform. If set, the value should be non-zero.
     minimum: 1
 
+  arm,no-completion-irq:
+    type: boolean
+    description:
+      This optional property is intended for hardware that does not generate
+      completion interrupts and can be used to unconditionally enable forced
+      polling mode of operation.
+
   arm,smc-id:
     $ref: /schemas/types.yaml#/definitions/uint32
     description:
@@ -379,6 +386,9 @@ then:
     - shmem
 
 else:
+  properties:
+    arm,no-completion-irq: false
+
   if:
     properties:
       compatible:
-- 
2.51.0

[PATCH v4 2/2] firmware: arm_scmi: Implement arm,no-completion-irq property

[Marek Vasut]

Implement new property arm,no-completion-irq, which sets all SCMI
operation into poll mode. This is meant to work around uncooperative
SCP implementations, which do not generate completion interrupts.
This applies to mbox/shmem based implementations.

With this property set, such implementations which do not generate
interrupts can be interacted with, until they are fixed to generate
interrupts properly.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Cristian Marussi <cristian.marussi@arm.com>
Cc: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: arm-scmi@vger.kernel.org
Cc: devicetree@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-renesas-soc@vger.kernel.org
---
V2: Drop no IRQ handling from SMC transport and update commit message
V3: Rename property from arm,poll-transport to arm,no-completion-irq
V4: No change
---
 drivers/firmware/arm_scmi/common.h | 4 ++++
 drivers/firmware/arm_scmi/driver.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 7c35c95fddbaf..7c9617d080a02 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -235,6 +235,9 @@ struct scmi_transport_ops {
  *		      to have an execution latency lesser-equal to the threshold
  *		      should be considered for atomic mode operation: such
  *		      decision is finally left up to the SCMI drivers.
+ * @no_completion_irq: Flag to indicate that this transport has no completion
+ *		       interrupt and has to be polled. This is similar to the
+ *		       force_polling below, except this is set via DT property.
  * @force_polling: Flag to force this whole transport to use SCMI core polling
  *		   mechanism instead of completion interrupts even if available.
  * @sync_cmds_completed_on_ret: Flag to indicate that the transport assures
@@ -254,6 +257,7 @@ struct scmi_desc {
 	int max_msg;
 	int max_msg_size;
 	unsigned int atomic_threshold;
+	bool no_completion_irq;
 	const bool force_polling;
 	const bool sync_cmds_completed_on_ret;
 	const bool atomic_enabled;
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 3e76a3204ba4f..f167194f7cf67 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -2735,6 +2735,7 @@ static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
 	cinfo->is_p2a = !tx;
 	cinfo->rx_timeout_ms = info->desc->max_rx_timeout_ms;
 	cinfo->max_msg_size = info->desc->max_msg_size;
+	cinfo->no_completion_irq = info->desc->no_completion_irq;
 
 	/* Create a unique name for this transport device */
 	snprintf(name, 32, "__scmi_transport_device_%s_%02X",
@@ -3150,6 +3151,9 @@ static const struct scmi_desc *scmi_transport_setup(struct device *dev)
 	if (ret && ret != -EINVAL)
 		dev_err(dev, "Malformed arm,max-msg DT property.\n");
 
+	trans->desc.no_completion_irq = of_property_read_bool(dev->of_node,
+							      "arm,no-completion-irq");
+
 	dev_info(dev,
 		 "SCMI max-rx-timeout: %dms / max-msg-size: %dbytes / max-msg: %d\n",
 		 trans->desc.max_rx_timeout_ms, trans->desc.max_msg_size,
-- 
2.51.0

Re: [PATCH v4 2/2] firmware: arm_scmi: Implement arm,no-completion-irq property

[Cristian Marussi]

On Sat, Jan 17, 2026 at 02:02:29AM +0100, Marek Vasut wrote:
> Implement new property arm,no-completion-irq, which sets all SCMI
> operation into poll mode. This is meant to work around uncooperative
> SCP implementations, which do not generate completion interrupts.
> This applies to mbox/shmem based implementations.
> 
> With this property set, such implementations which do not generate
> interrupts can be interacted with, until they are fixed to generate
> interrupts properly.
> 
> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> ---
> Cc: Conor Dooley <conor+dt@kernel.org>
> Cc: Cristian Marussi <cristian.marussi@arm.com>
> Cc: Florian Fainelli <florian.fainelli@broadcom.com>
> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Sudeep Holla <sudeep.holla@arm.com>
> Cc: arm-scmi@vger.kernel.org
> Cc: devicetree@vger.kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-renesas-soc@vger.kernel.org
> ---
> V2: Drop no IRQ handling from SMC transport and update commit message
> V3: Rename property from arm,poll-transport to arm,no-completion-irq
> V4: No change
> ---
>  drivers/firmware/arm_scmi/common.h | 4 ++++
>  drivers/firmware/arm_scmi/driver.c | 4 ++++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
> index 7c35c95fddbaf..7c9617d080a02 100644
> --- a/drivers/firmware/arm_scmi/common.h
> +++ b/drivers/firmware/arm_scmi/common.h
> @@ -235,6 +235,9 @@ struct scmi_transport_ops {
>   *		      to have an execution latency lesser-equal to the threshold
>   *		      should be considered for atomic mode operation: such
>   *		      decision is finally left up to the SCMI drivers.
> + * @no_completion_irq: Flag to indicate that this transport has no completion
> + *		       interrupt and has to be polled. This is similar to the
> + *		       force_polling below, except this is set via DT property.
>   * @force_polling: Flag to force this whole transport to use SCMI core polling
>   *		   mechanism instead of completion interrupts even if available.
>   * @sync_cmds_completed_on_ret: Flag to indicate that the transport assures
> @@ -254,6 +257,7 @@ struct scmi_desc {
>  	int max_msg;
>  	int max_msg_size;
>  	unsigned int atomic_threshold;
> +	bool no_completion_irq;
>  	const bool force_polling;
>  	const bool sync_cmds_completed_on_ret;
>  	const bool atomic_enabled;
> diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
> index 3e76a3204ba4f..f167194f7cf67 100644
> --- a/drivers/firmware/arm_scmi/driver.c
> +++ b/drivers/firmware/arm_scmi/driver.c
> @@ -2735,6 +2735,7 @@ static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
>  	cinfo->is_p2a = !tx;
>  	cinfo->rx_timeout_ms = info->desc->max_rx_timeout_ms;
>  	cinfo->max_msg_size = info->desc->max_msg_size;
> +	cinfo->no_completion_irq = info->desc->no_completion_irq;
>  
>  	/* Create a unique name for this transport device */
>  	snprintf(name, 32, "__scmi_transport_device_%s_%02X",
> @@ -3150,6 +3151,9 @@ static const struct scmi_desc *scmi_transport_setup(struct device *dev)
>  	if (ret && ret != -EINVAL)
>  		dev_err(dev, "Malformed arm,max-msg DT property.\n");
>  
> +	trans->desc.no_completion_irq = of_property_read_bool(dev->of_node,
> +							      "arm,no-completion-irq");
> +
>  	dev_info(dev,
>  		 "SCMI max-rx-timeout: %dms / max-msg-size: %dbytes / max-msg: %d\n",
>  		 trans->desc.max_rx_timeout_ms, trans->desc.max_msg_size,

LGTM.

Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>

Thanks,
Cristian

Re: [PATCH v4 2/2] firmware: arm_scmi: Implement arm,no-completion-irq property

[Marek Vasut]

On 1/19/26 5:57 PM, Cristian Marussi wrote:
> On Sat, Jan 17, 2026 at 02:02:29AM +0100, Marek Vasut wrote:
>> Implement new property arm,no-completion-irq, which sets all SCMI
>> operation into poll mode. This is meant to work around uncooperative
>> SCP implementations, which do not generate completion interrupts.
>> This applies to mbox/shmem based implementations.
>>
>> With this property set, such implementations which do not generate
>> interrupts can be interacted with, until they are fixed to generate
>> interrupts properly.
>>
>> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
>> ---
>> Cc: Conor Dooley <conor+dt@kernel.org>
>> Cc: Cristian Marussi <cristian.marussi@arm.com>
>> Cc: Florian Fainelli <florian.fainelli@broadcom.com>
>> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
>> Cc: Rob Herring <robh@kernel.org>
>> Cc: Sudeep Holla <sudeep.holla@arm.com>
>> Cc: arm-scmi@vger.kernel.org
>> Cc: devicetree@vger.kernel.org
>> Cc: linux-arm-kernel@lists.infradead.org
>> Cc: linux-renesas-soc@vger.kernel.org
>> ---
>> V2: Drop no IRQ handling from SMC transport and update commit message
>> V3: Rename property from arm,poll-transport to arm,no-completion-irq
>> V4: No change
>> ---
>>   drivers/firmware/arm_scmi/common.h | 4 ++++
>>   drivers/firmware/arm_scmi/driver.c | 4 ++++
>>   2 files changed, 8 insertions(+)
>>
>> diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
>> index 7c35c95fddbaf..7c9617d080a02 100644
>> --- a/drivers/firmware/arm_scmi/common.h
>> +++ b/drivers/firmware/arm_scmi/common.h
>> @@ -235,6 +235,9 @@ struct scmi_transport_ops {
>>    *		      to have an execution latency lesser-equal to the threshold
>>    *		      should be considered for atomic mode operation: such
>>    *		      decision is finally left up to the SCMI drivers.
>> + * @no_completion_irq: Flag to indicate that this transport has no completion
>> + *		       interrupt and has to be polled. This is similar to the
>> + *		       force_polling below, except this is set via DT property.
>>    * @force_polling: Flag to force this whole transport to use SCMI core polling
>>    *		   mechanism instead of completion interrupts even if available.
>>    * @sync_cmds_completed_on_ret: Flag to indicate that the transport assures
>> @@ -254,6 +257,7 @@ struct scmi_desc {
>>   	int max_msg;
>>   	int max_msg_size;
>>   	unsigned int atomic_threshold;
>> +	bool no_completion_irq;
>>   	const bool force_polling;
>>   	const bool sync_cmds_completed_on_ret;
>>   	const bool atomic_enabled;
>> diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
>> index 3e76a3204ba4f..f167194f7cf67 100644
>> --- a/drivers/firmware/arm_scmi/driver.c
>> +++ b/drivers/firmware/arm_scmi/driver.c
>> @@ -2735,6 +2735,7 @@ static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
>>   	cinfo->is_p2a = !tx;
>>   	cinfo->rx_timeout_ms = info->desc->max_rx_timeout_ms;
>>   	cinfo->max_msg_size = info->desc->max_msg_size;
>> +	cinfo->no_completion_irq = info->desc->no_completion_irq;
>>   
>>   	/* Create a unique name for this transport device */
>>   	snprintf(name, 32, "__scmi_transport_device_%s_%02X",
>> @@ -3150,6 +3151,9 @@ static const struct scmi_desc *scmi_transport_setup(struct device *dev)
>>   	if (ret && ret != -EINVAL)
>>   		dev_err(dev, "Malformed arm,max-msg DT property.\n");
>>   
>> +	trans->desc.no_completion_irq = of_property_read_bool(dev->of_node,
>> +							      "arm,no-completion-irq");
>> +
>>   	dev_info(dev,
>>   		 "SCMI max-rx-timeout: %dms / max-msg-size: %dbytes / max-msg: %d\n",
>>   		 trans->desc.max_rx_timeout_ms, trans->desc.max_msg_size,
> 
> LGTM.
> 
> Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>

Is there anything left to do with these patches, or can this now be 
picked up ?

Thank you.

Re: [PATCH v4 2/2] firmware: arm_scmi: Implement arm,no-completion-irq property

[Wolfram Sang]

Hi all,

> > > Implement new property arm,no-completion-irq, which sets all SCMI
> > > operation into poll mode. This is meant to work around uncooperative
> > > SCP implementations, which do not generate completion interrupts.
> > > This applies to mbox/shmem based implementations.
> > > 
> > > With this property set, such implementations which do not generate
> > > interrupts can be interacted with, until they are fixed to generate
> > > interrupts properly.
> > > 
> > > Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> > > ---

...

> > 
> > LGTM.
> > 
> > Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
> 
> Is there anything left to do with these patches, or can this now be picked
> up ?

Would love to see this going in. I also work with the firmware which
needs this functionality.

All the best,

   Wolfram

Re: [PATCH v4 2/2] firmware: arm_scmi: Implement arm,no-completion-irq property

[Cristian Marussi]

On Mon, Feb 09, 2026 at 11:56:25AM +0100, Wolfram Sang wrote:
> Hi all,
> 
> > > > Implement new property arm,no-completion-irq, which sets all SCMI
> > > > operation into poll mode. This is meant to work around uncooperative
> > > > SCP implementations, which do not generate completion interrupts.
> > > > This applies to mbox/shmem based implementations.
> > > > 
> > > > With this property set, such implementations which do not generate
> > > > interrupts can be interacted with, until they are fixed to generate
> > > > interrupts properly.
> > > > 
> > > > Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> > > > ---
> 
> ...
> 
> > > 
> > > LGTM.
> > > 
> > > Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
> > 
> > Is there anything left to do with these patches, or can this now be picked
> > up ?
> 
> Would love to see this going in. I also work with the firmware which
> needs this functionality.

I have not seen anymore push back around this, but I think it was late
anyway to be picked up as an update for this cycle given that it was
already -rc6 when the last series landed...so I guess it could picked up
now for the next cycle ...but I have not checked with Sudeep..

Thanks,
Cristian

Re: [PATCH v4 2/2] firmware: arm_scmi: Implement arm,no-completion-irq property

[Sudeep Holla]

On Mon, Feb 09, 2026 at 11:53:19AM +0100, Marek Vasut wrote:
> On 1/19/26 5:57 PM, Cristian Marussi wrote:
> > On Sat, Jan 17, 2026 at 02:02:29AM +0100, Marek Vasut wrote:
> > > Implement new property arm,no-completion-irq, which sets all SCMI
> > > operation into poll mode. This is meant to work around uncooperative
> > > SCP implementations, which do not generate completion interrupts.
> > > This applies to mbox/shmem based implementations.
> > > 
> > > With this property set, such implementations which do not generate
> > > interrupts can be interacted with, until they are fixed to generate
> > > interrupts properly.
> > > 
> > > Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> > > ---
> > > Cc: Conor Dooley <conor+dt@kernel.org>
> > > Cc: Cristian Marussi <cristian.marussi@arm.com>
> > > Cc: Florian Fainelli <florian.fainelli@broadcom.com>
> > > Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> > > Cc: Rob Herring <robh@kernel.org>
> > > Cc: Sudeep Holla <sudeep.holla@arm.com>
> > > Cc: arm-scmi@vger.kernel.org
> > > Cc: devicetree@vger.kernel.org
> > > Cc: linux-arm-kernel@lists.infradead.org
> > > Cc: linux-renesas-soc@vger.kernel.org
> > > ---
> > > V2: Drop no IRQ handling from SMC transport and update commit message
> > > V3: Rename property from arm,poll-transport to arm,no-completion-irq
> > > V4: No change
> > > ---
> > >   drivers/firmware/arm_scmi/common.h | 4 ++++
> > >   drivers/firmware/arm_scmi/driver.c | 4 ++++
> > >   2 files changed, 8 insertions(+)
> > > 
> > > diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
> > > index 7c35c95fddbaf..7c9617d080a02 100644
> > > --- a/drivers/firmware/arm_scmi/common.h
> > > +++ b/drivers/firmware/arm_scmi/common.h
> > > @@ -235,6 +235,9 @@ struct scmi_transport_ops {
> > >    *		      to have an execution latency lesser-equal to the threshold
> > >    *		      should be considered for atomic mode operation: such
> > >    *		      decision is finally left up to the SCMI drivers.
> > > + * @no_completion_irq: Flag to indicate that this transport has no completion
> > > + *		       interrupt and has to be polled. This is similar to the
> > > + *		       force_polling below, except this is set via DT property.
> > >    * @force_polling: Flag to force this whole transport to use SCMI core polling
> > >    *		   mechanism instead of completion interrupts even if available.
> > >    * @sync_cmds_completed_on_ret: Flag to indicate that the transport assures
> > > @@ -254,6 +257,7 @@ struct scmi_desc {
> > >   	int max_msg;
> > >   	int max_msg_size;
> > >   	unsigned int atomic_threshold;
> > > +	bool no_completion_irq;
> > >   	const bool force_polling;
> > >   	const bool sync_cmds_completed_on_ret;
> > >   	const bool atomic_enabled;
> > > diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
> > > index 3e76a3204ba4f..f167194f7cf67 100644
> > > --- a/drivers/firmware/arm_scmi/driver.c
> > > +++ b/drivers/firmware/arm_scmi/driver.c
> > > @@ -2735,6 +2735,7 @@ static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
> > >   	cinfo->is_p2a = !tx;
> > >   	cinfo->rx_timeout_ms = info->desc->max_rx_timeout_ms;
> > >   	cinfo->max_msg_size = info->desc->max_msg_size;
> > > +	cinfo->no_completion_irq = info->desc->no_completion_irq;
> > >   	/* Create a unique name for this transport device */
> > >   	snprintf(name, 32, "__scmi_transport_device_%s_%02X",
> > > @@ -3150,6 +3151,9 @@ static const struct scmi_desc *scmi_transport_setup(struct device *dev)
> > >   	if (ret && ret != -EINVAL)
> > >   		dev_err(dev, "Malformed arm,max-msg DT property.\n");
> > > +	trans->desc.no_completion_irq = of_property_read_bool(dev->of_node,
> > > +							      "arm,no-completion-irq");
> > > +
> > >   	dev_info(dev,
> > >   		 "SCMI max-rx-timeout: %dms / max-msg-size: %dbytes / max-msg: %d\n",
> > >   		 trans->desc.max_rx_timeout_ms, trans->desc.max_msg_size,
> > 
> > LGTM.
> > 
> > Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
> 
> Is there anything left to do with these patches, or can this now be picked
> up ?
> 

As I had mentioned here[1], I am happy with it and I will pick it up for
v7.1 once I start collecting the patches after v7.0-rc1. It just came in after
I had sent my PR to SoC team for v7.0

-- 
Regards,
Sudeep

[1] https://lore.kernel.org/all/aW5jwtoYCFs-Pzpk@bogus/

Re: [PATCH v4 2/2] firmware: arm_scmi: Implement arm,no-completion-irq property

[Marek Vasut]

On 2/9/26 4:44 PM, Sudeep Holla wrote:
> On Mon, Feb 09, 2026 at 11:53:19AM +0100, Marek Vasut wrote:
>> On 1/19/26 5:57 PM, Cristian Marussi wrote:
>>> On Sat, Jan 17, 2026 at 02:02:29AM +0100, Marek Vasut wrote:
>>>> Implement new property arm,no-completion-irq, which sets all SCMI
>>>> operation into poll mode. This is meant to work around uncooperative
>>>> SCP implementations, which do not generate completion interrupts.
>>>> This applies to mbox/shmem based implementations.
>>>>
>>>> With this property set, such implementations which do not generate
>>>> interrupts can be interacted with, until they are fixed to generate
>>>> interrupts properly.
>>>>
>>>> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
>>>> ---
>>>> Cc: Conor Dooley <conor+dt@kernel.org>
>>>> Cc: Cristian Marussi <cristian.marussi@arm.com>
>>>> Cc: Florian Fainelli <florian.fainelli@broadcom.com>
>>>> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
>>>> Cc: Rob Herring <robh@kernel.org>
>>>> Cc: Sudeep Holla <sudeep.holla@arm.com>
>>>> Cc: arm-scmi@vger.kernel.org
>>>> Cc: devicetree@vger.kernel.org
>>>> Cc: linux-arm-kernel@lists.infradead.org
>>>> Cc: linux-renesas-soc@vger.kernel.org
>>>> ---
>>>> V2: Drop no IRQ handling from SMC transport and update commit message
>>>> V3: Rename property from arm,poll-transport to arm,no-completion-irq
>>>> V4: No change
>>>> ---
>>>>    drivers/firmware/arm_scmi/common.h | 4 ++++
>>>>    drivers/firmware/arm_scmi/driver.c | 4 ++++
>>>>    2 files changed, 8 insertions(+)
>>>>
>>>> diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
>>>> index 7c35c95fddbaf..7c9617d080a02 100644
>>>> --- a/drivers/firmware/arm_scmi/common.h
>>>> +++ b/drivers/firmware/arm_scmi/common.h
>>>> @@ -235,6 +235,9 @@ struct scmi_transport_ops {
>>>>     *		      to have an execution latency lesser-equal to the threshold
>>>>     *		      should be considered for atomic mode operation: such
>>>>     *		      decision is finally left up to the SCMI drivers.
>>>> + * @no_completion_irq: Flag to indicate that this transport has no completion
>>>> + *		       interrupt and has to be polled. This is similar to the
>>>> + *		       force_polling below, except this is set via DT property.
>>>>     * @force_polling: Flag to force this whole transport to use SCMI core polling
>>>>     *		   mechanism instead of completion interrupts even if available.
>>>>     * @sync_cmds_completed_on_ret: Flag to indicate that the transport assures
>>>> @@ -254,6 +257,7 @@ struct scmi_desc {
>>>>    	int max_msg;
>>>>    	int max_msg_size;
>>>>    	unsigned int atomic_threshold;
>>>> +	bool no_completion_irq;
>>>>    	const bool force_polling;
>>>>    	const bool sync_cmds_completed_on_ret;
>>>>    	const bool atomic_enabled;
>>>> diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
>>>> index 3e76a3204ba4f..f167194f7cf67 100644
>>>> --- a/drivers/firmware/arm_scmi/driver.c
>>>> +++ b/drivers/firmware/arm_scmi/driver.c
>>>> @@ -2735,6 +2735,7 @@ static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
>>>>    	cinfo->is_p2a = !tx;
>>>>    	cinfo->rx_timeout_ms = info->desc->max_rx_timeout_ms;
>>>>    	cinfo->max_msg_size = info->desc->max_msg_size;
>>>> +	cinfo->no_completion_irq = info->desc->no_completion_irq;
>>>>    	/* Create a unique name for this transport device */
>>>>    	snprintf(name, 32, "__scmi_transport_device_%s_%02X",
>>>> @@ -3150,6 +3151,9 @@ static const struct scmi_desc *scmi_transport_setup(struct device *dev)
>>>>    	if (ret && ret != -EINVAL)
>>>>    		dev_err(dev, "Malformed arm,max-msg DT property.\n");
>>>> +	trans->desc.no_completion_irq = of_property_read_bool(dev->of_node,
>>>> +							      "arm,no-completion-irq");
>>>> +
>>>>    	dev_info(dev,
>>>>    		 "SCMI max-rx-timeout: %dms / max-msg-size: %dbytes / max-msg: %d\n",
>>>>    		 trans->desc.max_rx_timeout_ms, trans->desc.max_msg_size,
>>>
>>> LGTM.
>>>
>>> Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
>>
>> Is there anything left to do with these patches, or can this now be picked
>> up ?
>>
> 
> As I had mentioned here[1], I am happy with it and I will pick it up for
> v7.1 once I start collecting the patches after v7.0-rc1. It just came in after
> I had sent my PR to SoC team for v7.0
OK, thank you

Re: [PATCH v4 2/2] firmware: arm_scmi: Implement arm,no-completion-irq property

[Wolfram Sang]

> As I had mentioned here[1], I am happy with it and I will pick it up for
> v7.1 once I start collecting the patches after v7.0-rc1. It just came in after
> I had sent my PR to SoC team for v7.0

Great, 7.1 is good, thank you!

Re: [PATCH v4 1/2] dt-bindings: firmware: arm,scmi: Document arm,no-completion-irq property

[Cristian Marussi]

On Sat, Jan 17, 2026 at 02:02:28AM +0100, Marek Vasut wrote:
> Document new property arm,no-completion-irq . This optional property
> is intended for hardware that does not generate completion interrupts
> and can be used to unconditionally enable forced polling mode of
> operation.
> 
> With this property set, such implementations which do not generate
> interrupts can be interacted with, until they are fixed to generate
> interrupts properly.
> 
> Note that, because the original base protocol exchange also requires
> some sort of completion mechanism, it is not possible to query SCMI
> itself for this property and it must be described in DT. While this
> does look a bit like policy, the SCMI provider is part of the
> hardware, hence DT.
> 
> Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> ---
> Cc: Conor Dooley <conor+dt@kernel.org>
> Cc: Cristian Marussi <cristian.marussi@arm.com>
> Cc: Florian Fainelli <florian.fainelli@broadcom.com>
> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Sudeep Holla <sudeep.holla@arm.com>
> Cc: arm-scmi@vger.kernel.org
> Cc: devicetree@vger.kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-renesas-soc@vger.kernel.org
> ---
> V2: s@mean@&t and limit poll transport to mailbox/shmem only
> V3: - Reformat the commit message, expand property description to
>       explicitly spell out this is hardware description.
>     - Rename property from arm,poll-transport to arm,no-completion-irq
> V4: - Update first paragraph of commit message and property description
>     - Add RB from Rob
> ---
>  .../devicetree/bindings/firmware/arm,scmi.yaml         | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> index be817fd9cc34b..d06cca9273c48 100644
> --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> @@ -146,6 +146,13 @@ properties:
>        this platform. If set, the value should be non-zero.
>      minimum: 1
>  
> +  arm,no-completion-irq:
> +    type: boolean
> +    description:

Shouldn't these two points have to be swapped as per Sudeep and Rob
suggestions ?

    description:
	....
    type: boolean

> +      This optional property is intended for hardware that does not generate
> +      completion interrupts and can be used to unconditionally enable forced
> +      polling mode of operation.
> +
>    arm,smc-id:
>      $ref: /schemas/types.yaml#/definitions/uint32
>      description:
> @@ -379,6 +386,9 @@ then:
>      - shmem
>  
>  else:
> +  properties:
> +    arm,no-completion-irq: false
> +
>    if:
>      properties:

With the above corrected, LGTM.

Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>

Thanks,
Cristian

Re: [PATCH v4 1/2] dt-bindings: firmware: arm,scmi: Document arm,no-completion-irq property

[Sudeep Holla]

On Mon, Jan 19, 2026 at 04:53:45PM +0000, Cristian Marussi wrote:
> On Sat, Jan 17, 2026 at 02:02:28AM +0100, Marek Vasut wrote:
> > Document new property arm,no-completion-irq . This optional property
> > is intended for hardware that does not generate completion interrupts
> > and can be used to unconditionally enable forced polling mode of
> > operation.
> > 
> > With this property set, such implementations which do not generate
> > interrupts can be interacted with, until they are fixed to generate
> > interrupts properly.
> > 
> > Note that, because the original base protocol exchange also requires
> > some sort of completion mechanism, it is not possible to query SCMI
> > itself for this property and it must be described in DT. While this
> > does look a bit like policy, the SCMI provider is part of the
> > hardware, hence DT.
> > 
> > Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
> > Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> > ---
> > Cc: Conor Dooley <conor+dt@kernel.org>
> > Cc: Cristian Marussi <cristian.marussi@arm.com>
> > Cc: Florian Fainelli <florian.fainelli@broadcom.com>
> > Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> > Cc: Rob Herring <robh@kernel.org>
> > Cc: Sudeep Holla <sudeep.holla@arm.com>
> > Cc: arm-scmi@vger.kernel.org
> > Cc: devicetree@vger.kernel.org
> > Cc: linux-arm-kernel@lists.infradead.org
> > Cc: linux-renesas-soc@vger.kernel.org
> > ---
> > V2: s@mean@&t and limit poll transport to mailbox/shmem only
> > V3: - Reformat the commit message, expand property description to
> >       explicitly spell out this is hardware description.
> >     - Rename property from arm,poll-transport to arm,no-completion-irq
> > V4: - Update first paragraph of commit message and property description
> >     - Add RB from Rob
> > ---
> >  .../devicetree/bindings/firmware/arm,scmi.yaml         | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> > index be817fd9cc34b..d06cca9273c48 100644
> > --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> > +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> > @@ -146,6 +146,13 @@ properties:
> >        this platform. If set, the value should be non-zero.
> >      minimum: 1
> >  
> > +  arm,no-completion-irq:
> > +    type: boolean
> > +    description:
> 
> Shouldn't these two points have to be swapped as per Sudeep and Rob
> suggestions ?
> 
>     description:
> 	....
>     type: boolean
> 

I was just referring to the points covered under the `description` and not
the order of `type` and `description`. I am not sure if there is any such
requirement as well. I am happy with this version, but this needs to wait
for the merge window following the next as I have already sent the PR to
SoC teams.

-- 
Regards,
Sudeep

Re: [PATCH v4 1/2] dt-bindings: firmware: arm,scmi: Document arm,no-completion-irq property

[Rob Herring]

On Mon, Jan 19, 2026 at 05:02:58PM +0000, Sudeep Holla wrote:
> On Mon, Jan 19, 2026 at 04:53:45PM +0000, Cristian Marussi wrote:
> > On Sat, Jan 17, 2026 at 02:02:28AM +0100, Marek Vasut wrote:
> > > Document new property arm,no-completion-irq . This optional property
> > > is intended for hardware that does not generate completion interrupts
> > > and can be used to unconditionally enable forced polling mode of
> > > operation.
> > > 
> > > With this property set, such implementations which do not generate
> > > interrupts can be interacted with, until they are fixed to generate
> > > interrupts properly.
> > > 
> > > Note that, because the original base protocol exchange also requires
> > > some sort of completion mechanism, it is not possible to query SCMI
> > > itself for this property and it must be described in DT. While this
> > > does look a bit like policy, the SCMI provider is part of the
> > > hardware, hence DT.
> > > 
> > > Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
> > > Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> > > ---
> > > Cc: Conor Dooley <conor+dt@kernel.org>
> > > Cc: Cristian Marussi <cristian.marussi@arm.com>
> > > Cc: Florian Fainelli <florian.fainelli@broadcom.com>
> > > Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> > > Cc: Rob Herring <robh@kernel.org>
> > > Cc: Sudeep Holla <sudeep.holla@arm.com>
> > > Cc: arm-scmi@vger.kernel.org
> > > Cc: devicetree@vger.kernel.org
> > > Cc: linux-arm-kernel@lists.infradead.org
> > > Cc: linux-renesas-soc@vger.kernel.org
> > > ---
> > > V2: s@mean@&t and limit poll transport to mailbox/shmem only
> > > V3: - Reformat the commit message, expand property description to
> > >       explicitly spell out this is hardware description.
> > >     - Rename property from arm,poll-transport to arm,no-completion-irq
> > > V4: - Update first paragraph of commit message and property description
> > >     - Add RB from Rob
> > > ---
> > >  .../devicetree/bindings/firmware/arm,scmi.yaml         | 10 ++++++++++
> > >  1 file changed, 10 insertions(+)
> > > 
> > > diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> > > index be817fd9cc34b..d06cca9273c48 100644
> > > --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> > > +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> > > @@ -146,6 +146,13 @@ properties:
> > >        this platform. If set, the value should be non-zero.
> > >      minimum: 1
> > >  
> > > +  arm,no-completion-irq:
> > > +    type: boolean
> > > +    description:
> > 
> > Shouldn't these two points have to be swapped as per Sudeep and Rob
> > suggestions ?
> > 
> >     description:
> > 	....
> >     type: boolean
> > 
> 
> I was just referring to the points covered under the `description` and not
> the order of `type` and `description`. I am not sure if there is any such
> requirement as well.

There isn't. The only preference is to be consistent within a file of 
description either first or last.

Rob

Re: [PATCH v4 1/2] dt-bindings: firmware: arm,scmi: Document arm,no-completion-irq property

[Marek Vasut]

On 1/19/26 5:53 PM, Cristian Marussi wrote:

[...]

>> diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
>> index be817fd9cc34b..d06cca9273c48 100644
>> --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
>> +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
>> @@ -146,6 +146,13 @@ properties:
>>         this platform. If set, the value should be non-zero.
>>       minimum: 1
>>   
>> +  arm,no-completion-irq:
>> +    type: boolean
>> +    description:
> 
> Shouldn't these two points have to be swapped as per Sudeep and Rob
> suggestions ?
> 
>      description:
> 	....
>      type: boolean
> 
>> +      This optional property is intended for hardware that does not generate
>> +      completion interrupts and can be used to unconditionally enable forced
>> +      polling mode of operation.
>> +
>>     arm,smc-id:
>>       $ref: /schemas/types.yaml#/definitions/uint32
>>       description:

They were referring to the content of the description: . Note that the 
type precedes the description: , see e.g. arm,smc-id above or any of the 
other properties.

Re: [PATCH v4 1/2] dt-bindings: firmware: arm,scmi: Document arm,no-completion-irq property

[Sudeep Holla]

On Sat, 17 Jan 2026 02:02:28 +0100, Marek Vasut wrote:
> Document new property arm,no-completion-irq . This optional property
> is intended for hardware that does not generate completion interrupts
> and can be used to unconditionally enable forced polling mode of
> operation.
> 
> With this property set, such implementations which do not generate
> interrupts can be interacted with, until they are fixed to generate
> interrupts properly.
> 
> [...]

Applied to sudeep.holla/linux (for-next/scmi/updates), thanks!

[1/2] dt-bindings: firmware: arm,scmi: Document arm,no-completion-irq property
      https://git.kernel.org/sudeep.holla/c/0c5453bf8437
[2/2] firmware: arm_scmi: Implement arm,no-completion-irq property
      https://git.kernel.org/sudeep.holla/c/d8283ac2c8fb
--
Regards,
Sudeep