Re: [PATCH] arm64: dts: qcom: shikra: Add qcom,vmid to BAM-DMA node

On 31-07-2026 02:49 am, Bjorn Andersson wrote:
> On Tue, Jul 14, 2026 at 02:01:53PM +0530, Vishnu Santhosh wrote:
>> On the Qualcomm Shikra SoC the mDSP (VMID 43 / QCOM_SCM_VMID_NAV) is
>> the AXI master for BAM descriptor FIFO accesses. The XPU enforces
>> per-region access control; without an SCM assignment granting NAV
>> access, the first DMA transfer triggers an XPU violation.
>>
> I'm a bit puzzled about your plan here.
>
> You posted this on July 14th, that's 3 days after I asked you to rebase
> patch [1]. This patch literally says that [1] is broken and untested.

The XPU violation itself wasn't visible against the base bam-dmux
enablement alone. It only showed up once the access-control policy was
enabled, which happened to land close to when [1] was posted upstream.
That's why this series followed so soon after.

>> Add qcom,vmid = <QCOM_SCM_VMID_NAV> to the bam_dmux_dma controller
>> node so bam_dma SCM-assigns each channel descriptor FIFO at
>> allocation. BAM-DMUX itself is a singleton and no longer needs a DT
>> property for its destination VMID: the driver now selects
>> QCOM_SCM_VMID_NAV internally via the qcom,shikra-bam-dmux compatible's
>> match data.
>>
>> Co-developed-by: Deepak Kumar Singh <[email protected]>
>> Signed-off-by: Deepak Kumar Singh <[email protected]>
>> Signed-off-by: Vishnu Santhosh <[email protected]>
>> ---
>> This depends on three separate series:
>>
>> - "arm64: dts: qcom: shikra: Add BAM-DMUX support" [1], which adds
>>    the bam_dmux and bam_dmux_dma nodes this series modifies.
>> - "arm64: dts: qcom: Extend Shikra device tree with CDSP, LPAICP,
>>    MPSS remoteproc PAS and peripherals" [2], which is still under
>>    review and adds the "remoteproc_mpss" node that [1] attaches
>>    bam_dmux to.
>> - "dt-bindings: dma: qcom,bam-dma: Add optional qcom,vmid property" [3]
>>    and "dt-bindings: net: qcom,bam-dmux: Add qcom,shikra-bam-dmux
>>    compatible" [4], which introduce the qcom,shikra-bam-dma and
>>    qcom,shikra-bam-dmux compatibles this series relies on for the
>>    qcom,vmid property to validate under dt-schema.
>>
>> [1] https://lore.kernel.org/all/20260711-qcom-shikra-dts-bam-dmux-v2-1-d5b33ee32138@oss.qualcomm.com/
> Changes was requested on July 11th
>
>> [2] https://lore.kernel.org/all/[email protected]/
> Changes was requested on July 13th
>
>> [3] https://lore.kernel.org/all/20260714-qcom-bam-dma-vmid-ext-v1-0-cef87c57b7dc@oss.qualcomm.com/
>> [4] https://lore.kernel.org/all/20260714-qcom-bam-dmux-vmid-ext-v1-0-3f29da7cca76@oss.qualcomm.com/
> Might be wrong on the timezones, but I think you had change requests in
> your inbox by the time you posted this series.
>
>
> What do you want me to do with this patch?

Understood the mistake. I should have waited for [1]'s dependencies to land, then folded this vmid
change into [1] itself.  I will do that and post these changes as [1]'s next revision.

Please drop this patch.

>
>> ---
>>   arch/arm64/boot/dts/qcom/shikra.dtsi | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm64/boot/dts/qcom/shikra.dtsi b/arch/arm64/boot/dts/qcom/shikra.dtsi
>> index 246ea74d1fb1e293f0428d342301886dc52cb179..cb824da1757921edf0befe5480bf489ee1d8c727 100644
>> --- a/arch/arm64/boot/dts/qcom/shikra.dtsi
>> +++ b/arch/arm64/boot/dts/qcom/shikra.dtsi
>> @@ -5,6 +5,7 @@
>>   
>>   #include <dt-bindings/clock/qcom,rpmcc.h>
>>   #include <dt-bindings/clock/qcom,shikra-gcc.h>
>> +#include <dt-bindings/firmware/qcom,scm.h>
>>   #include <dt-bindings/interconnect/qcom,icc.h>
>>   #include <dt-bindings/interconnect/qcom,osm-l3.h>
>>   #include <dt-bindings/dma/qcom-gpi.h>
>> @@ -1888,7 +1889,7 @@ glink-edge {
>>   			};
>>   
>>   			bam_dmux: bam-dmux {
>> -				compatible = "qcom,bam-dmux";
>> +				compatible = "qcom,shikra-bam-dmux", "qcom,bam-dmux";
>>   
>>   				interrupts-extended = <&modem_smsm 1 IRQ_TYPE_EDGE_BOTH>,
>>   						      <&modem_smsm 11 IRQ_TYPE_EDGE_BOTH>;
>> @@ -2030,7 +2031,7 @@ glink-edge {
>>   		};
>>   
>>   		bam_dmux_dma: dma-controller@6044000 {
>> -			compatible = "qcom,bam-v1.7.0";
>> +			compatible = "qcom,shikra-bam-dma", "qcom,bam-v1.7.0";
>>   			reg = <0x0 0x06044000 0x0 0x19000>;
>>   			interrupts = <GIC_SPI 74 IRQ_TYPE_EDGE_RISING 0>;
>>   			#dma-cells = <1>;
>> @@ -2039,6 +2040,7 @@ bam_dmux_dma: dma-controller@6044000 {
>>   			num-channels = <6>;
>>   			qcom,num-ees = <1>;
>>   			qcom,powered-remotely;
>> +			qcom,vmid = <QCOM_SCM_VMID_NAV>;
>>   		};
>>   
>>   		sram@c11e000 {
>>
>> ---
>> base-commit: 3b029c035b34bbc693405ddf759f0e9b920c27f1
>> change-id: 20260714-b4-qcom-shikra-dts-bam-dmux-vmid-ext-1b4f793e035c
>> prerequisite-change-id: 20260525-shikra-dt-m1-082dec382e7f:v6
>> prerequisite-patch-id: 48ecd66c06c4fad81f91283c26ec57d95bbde29d
>> prerequisite-patch-id: 7d92e5a301d09616840e54dc9e4a81f30a64383c
>> prerequisite-patch-id: be1a16f53e23dd5ab90210a056c9da3559c6186d
>> prerequisite-patch-id: 3eff04500c55100c763aeac1f1f8c5768d500500
>> prerequisite-patch-id: ab22c5fdb2fa65b78ffef76bbe4459c8d5ffe7b2
>> prerequisite-patch-id: cb24efedb648271ef5c60ace96e2366d89254e8f
>> prerequisite-patch-id: 8be7df0395c5847a988c7e814c7db878b5932b11
>> prerequisite-patch-id: 0510992d022cef7317b6efee6765ac78c0225356
>> prerequisite-patch-id: de4327fcbe81f92a337f429b74e8220969a5b79f
>> prerequisite-patch-id: e13435365cba0b6ecfcea6d9e5ab72838fba23a7
>> prerequisite-patch-id: 90f78668eb969c16ed8c2485d75a60a183fc4b8e
>> prerequisite-change-id: 20260603-qcom-shikra-dts-bam-dmux-7fdcbb6fb662:v2
>> prerequisite-patch-id: 59bb0a7828e41f546f734f127d81da83c0adcda9
>> prerequisite-patch-id: 197da6bcb15cadc47869dba88c8020987b25c335
>> prerequisite-patch-id: 8ec9c1eb03f052ae232ed54117abed38672c23f6
>> prerequisite-patch-id: 350db4f4bcdfc0fad9ed57cd5b1723f85ad44f5d
>> prerequisite-patch-id: b5d7f75df02fde56181f576a936baf09d0a72276
>> prerequisite-patch-id: 3ce52e07ae57139c2e2b71a29ed7d7250f6fcc87
>> prerequisite-patch-id: 3a689e8dda5fd2755b689d94d095806b3f2e6eed
>> prerequisite-patch-id: ac83151a889855498d36288ddd36216d451340c8
>> prerequisite-patch-id: 2357cac636e019eaf14d6a493a1c72bca56fe405
>> prerequisite-patch-id: 2885f299e711582da312ca9d13983d296a3dd5dc
>> prerequisite-patch-id: 91af5f3c01e766a53ce8de69aa21847a2d6bbbf8
>> prerequisite-patch-id: 48ecd66c06c4fad81f91283c26ec57d95bbde29d
>> prerequisite-patch-id: 7d92e5a301d09616840e54dc9e4a81f30a64383c
>> prerequisite-patch-id: be1a16f53e23dd5ab90210a056c9da3559c6186d
>> prerequisite-patch-id: 3eff04500c55100c763aeac1f1f8c5768d500500
>> prerequisite-patch-id: ab22c5fdb2fa65b78ffef76bbe4459c8d5ffe7b2
>> prerequisite-patch-id: cb24efedb648271ef5c60ace96e2366d89254e8f
>> prerequisite-patch-id: 8be7df0395c5847a988c7e814c7db878b5932b11
>> prerequisite-patch-id: 0510992d022cef7317b6efee6765ac78c0225356
>> prerequisite-patch-id: de4327fcbe81f92a337f429b74e8220969a5b79f
>> prerequisite-patch-id: 968bffc36646412f8289b917f37e762a4297bcc8
>> prerequisite-patch-id: 35944403bd4480caad12657342da15ea71c6afbd
>> prerequisite-patch-id: 65b485474126f4a2ab3f69a0b8e146b3b04c2c1a
>> prerequisite-change-id: 20260714-qcom-bam-dma-vmid-ext-8a3bd3c5c00e:v1
>> prerequisite-patch-id: b61d337d6c8fc4b20bff5a057b3f3335d89c57c3
>> prerequisite-patch-id: 91d3d344ec3e35ef7a3cec0a2ef90fefaf10a039
>> prerequisite-patch-id: 9e23abde2db60a3ad3a00d060bfb91f68c0aa798
>> prerequisite-patch-id: 4fa3350725e5b9d442247756d2b51d03f99b86bc
> So this patch has almost been tested upstream, only 38 patches delta?
>
> Regards,
> Bjorn

Understood. That's a lot of unlanded prerequisites to stack a patch on.
I'll be mindful next time.


Thanks,
Vishnu

>
>> Best regards,
>> -- 
>> Vishnu Santhosh <[email protected]>
>>