[PATCH net-next v2 1/2] dt-bindings: net: qcom,bam-dmux: Add memory-region and qcom,vmid properties
From: Vishnu Santhosh <hidden>
Date: 2026-09-20 03:03:05
Also in:
linux-arm-msm, linux-devicetree, lkml
Subsystem:
arm/qualcomm mailing list, networking drivers, open firmware and flattened device tree bindings, qualcomm bam-dmux wwan network driver, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Stephan Gerhold, Linus Torvalds
Some Qualcomm SoCs, such as Shikra, run the modem in a separate security domain with restricted access to system memory. BAM-DMUX DMA mappings must therefore be constrained to a designated region that can be shared with the modem. Add an optional memory-region property to reference a restricted DMA pool used for BAM-DMUX mappings, and a qcom,vmid property to identify the remote execution environment that is granted access to the pool through SCM. Require memory-region whenever qcom,vmid is specified. Co-developed-by: Deepak Kumar Singh <redacted> Signed-off-by: Deepak Kumar Singh <redacted> Signed-off-by: Vishnu Santhosh <redacted> --- .../devicetree/bindings/net/qcom,bam-dmux.yaml | 38 ++++++++++++++++++++++ 1 file changed, 38 insertions(+)
diff --git a/Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml b/Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml
index 33746c238513d72366bc52359fb10f275475b331..5351269b0ab72ede808ae47b55d57580af209038 100644
--- a/Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml
+++ b/Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml@@ -72,6 +72,24 @@ properties: - const: tx - const: rx + memory-region: + maxItems: 1 + description: + Phandle to a reserved-memory node compatible with restricted-dma-pool. + The BAM-DMUX device uses the pool for DMA mappings. + + qcom,vmid: + $ref: /schemas/types.yaml#/definitions/uint32-array + minItems: 1 + maxItems: 1 + items: + minimum: 1 + maximum: 63 + description: + VMID of the remote execution environment that is granted access to the + restricted DMA pool through SCM. The local execution environment is + retained automatically and must not be specified. + required: - compatible - interrupts
@@ -81,12 +99,29 @@ required: - dmas - dma-names +dependencies: + qcom,vmid: [ memory-region ] + additionalProperties: false examples: - | + #include <dt-bindings/firmware/qcom,scm.h> #include <dt-bindings/interrupt-controller/irq.h> + reserved-memory { + #address-cells = <1>; + #size-cells = <1>; + ranges; + + bam_dmux_pool: restricted-dma-pool { + compatible = "restricted-dma-pool"; + size = <0x40000>; + alignment = <0x40000>; + alloc-ranges = <0x80000000 0x80000000>; + }; + }; + mpss: remoteproc { bam-dmux { compatible = "qcom,bam-dmux";
@@ -100,5 +135,8 @@ examples: dmas = <&bam_dmux_dma 4>, <&bam_dmux_dma 5>; dma-names = "tx", "rx"; + + memory-region = <&bam_dmux_pool>; + qcom,vmid = <QCOM_SCM_VMID_NAV>; }; };
--
2.34.1