Re: [PATCH] arm64: dts: qcom: shikra: Add BAM-DMUX support

[Vishnu Santhosh <vishnu.santhosh@oss.qualcomm.com>]

On 11-06-2026 02:25 pm, Stephan Gerhold wrote:
> On Thu, Jun 11, 2026 at 02:11:59PM +0530, Vishnu Santhosh wrote:
>> Add required nodes to enable the upstream BAM-DMUX WWAN driver on
>> Qualcomm Shikra SoC.
>>
>> The SMSM (Shared Memory State Machine) node provides the power
>> control signaling between the AP and modem for BAM-DMUX. The
>> BAM DMA controller node describes the A2 modem BAM hardware as a
>> standard DMA controller. The BAM-DMUX node references the DMA
>> channels and the pc/pc-ack interrupt lines from the modem SMSM
>> entry for power control signaling.
>>
>> Signed-off-by: Vishnu Santhosh <vishnu.santhosh@oss.qualcomm.com>
> I'm quite surprised to see this 15+ years(?) old hardware block being
> brought back to a new SoC. Is Shikra not using IPA?
>
>> ---
>>   arch/arm64/boot/dts/qcom/shikra.dtsi | 51 ++++++++++++++++++++++++++++++++++++
>>   1 file changed, 51 insertions(+)
>>
>> diff --git a/arch/arm64/boot/dts/qcom/shikra.dtsi b/arch/arm64/boot/dts/qcom/shikra.dtsi
>> index a4334d99c1f35ee851ca8266ec37d4a200a07ee5..3e59d5f6323c0d857f376316faa26c503e67f6bc 100644
>> --- a/arch/arm64/boot/dts/qcom/shikra.dtsi
>> +++ b/arch/arm64/boot/dts/qcom/shikra.dtsi
>> @@ -17,6 +17,23 @@ / {
>>   	#address-cells = <2>;
>>   	#size-cells = <2>;
>>   
>> +	bam_dmux: bam-dmux {
>> +		compatible = "qcom,bam-dmux";
>> +
>> +		interrupts-extended = <&modem_smsm 1 IRQ_TYPE_EDGE_BOTH>,
>> +				      <&modem_smsm 11 IRQ_TYPE_EDGE_BOTH>;
>> +		interrupt-names = "pc",
>> +				  "pc-ack";
>> +
>> +		qcom,smem-states = <&apps_smsm 1>,
>> +				   <&apps_smsm 11>;
>> +		qcom,smem-state-names = "pc",
>> +					"pc-ack";
>> +
>> +		dmas = <&bam_dmux_dma 4>, <&bam_dmux_dma 5>;
>> +		dma-names = "tx", "rx";
>> +	};
> This should be a child node of the modem remoteproc. See msm8916.dtsi
> for example.
>
>> +
>>   	clocks {
>>   		xo_board: xo-board {
>>   			compatible = "fixed-clock";
>> @@ -314,6 +331,28 @@ lmcu_dtb_mem: lmcu-dtb@b4702000 {
>>   		};
>>   	};
>>   
>> +	smsm {
>> +		compatible = "qcom,smsm";
>> +
>> +		#address-cells = <1>;
>> +		#size-cells = <0>;
>> +
>> +		mboxes = <0>, <&apcs_glb 13>;
>> +
>> +		apps_smsm: apps@0 {
>> +			reg = <0>;
>> +			#qcom,smem-state-cells = <1>;
>> +		};
>> +
>> +		modem_smsm: modem@1 {
>> +			reg = <1>;
>> +			interrupts = <GIC_SPI 69 IRQ_TYPE_EDGE_RISING 0>;
>> +
>> +			interrupt-controller;
>> +			#interrupt-cells = <2>;
>> +		};
>> +	};
>> +
>>   	soc: soc@0 {
>>   		compatible = "simple-bus";
>>   
>> @@ -640,6 +679,18 @@ &clk_virt SLAVE_QUP_CORE_0 RPM_ALWAYS_TAG>,
>>   			};
>>   		};
>>   
>> +		bam_dmux_dma: dma-controller@6044000 {
>> +			compatible = "qcom,bam-v1.7.0";
>> +			reg = <0x0 0x06044000 0x0 0x19000>;
>> +			interrupts = <GIC_SPI 74 IRQ_TYPE_EDGE_RISING 0>;
>> +			#dma-cells = <1>;
>> +			qcom,ee = <0>;
>> +
>> +			num-channels = <6>;
>> +			qcom,num-ees = <1>;
>> +			qcom,powered-remotely;
>> +		};
>> +
>>   		sram@c11e000 {
>>   			compatible = "qcom,shikra-imem", "mmio-sram";
>>   			reg = <0x0 0x0c11e000 0x0 0x1000>;
>>
>> ---
>> base-commit: ba3e43a9e601636f5edb54e259a74f96ca3b8fd8
>> change-id: 20260603-qcom-shikra-dts-bam-dmux-7fdcbb6fb662
>> prerequisite-message-id: <20260527-shikra-dt-v4-0-b5ca1fa0b392@oss.qualcomm.com>
>> prerequisite-patch-id: 3a689e8dda5fd2755b689d94d095806b3f2e6eed
>> prerequisite-patch-id: 2acc300a68ed8c5364fb5f2f7d28fc0d56ab07bf
>> prerequisite-patch-id: 2357cac636e019eaf14d6a493a1c72bca56fe405
>> prerequisite-patch-id: 2885f299e711582da312ca9d13983d296a3dd5dc
>> prerequisite-patch-id: 91af5f3c01e766a53ce8de69aa21847a2d6bbbf8
>>
> If the DT isn't merged yet, you can also just squash that into the
> existing series that adds the modem remoteproc.
>
> Thanks,
> Stephan

Since the existing series is already in a stable state, the author
does not want to add any more patches to it. Therefore, I will
update the current patch with the DT changes you suggested and
submit a separate patch to incorporate the corresponding driver
changes.


Thanks,
Vishnu