[PATCH net-next v3 1/2] dt-bindings: net: Add schema for Qualcomm BAM-DMUX

From: Stephan Gerhold
Date: Sat Nov 27 2021 - 12:41:37 EST


The BAM Data Multiplexer provides access to the network data channels of
modems integrated into many older Qualcomm SoCs, e.g. Qualcomm MSM8916 or
MSM8974. It is built using a simple protocol layer on top of a DMA engine
(Qualcomm BAM) and bidirectional interrupts to coordinate power control.

The device tree node combines the incoming interrupt with the outgoing
interrupts (smem-states) as well as the two DMA channels, which allows
the BAM-DMUX driver to request all necessary resources.

Signed-off-by: Stephan Gerhold <stephan@xxxxxxxxxxx>
---
Changes in v2: Clarify that bam-dmux does not directly describe a hardware
block but actually a "firmware convention" that combines
different hardware blocks that are described separately.
Changes since RFC: None.
---
.../bindings/net/qcom,bam-dmux.yaml | 92 +++++++++++++++++++
1 file changed, 92 insertions(+)
create mode 100644 Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml

diff --git a/Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml b/Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml
new file mode 100644
index 000000000000..b30544410d09
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml
@@ -0,0 +1,92 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/qcom,bam-dmux.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm BAM Data Multiplexer
+
+maintainers:
+ - Stephan Gerhold <stephan@xxxxxxxxxxx>
+
+description: |
+ The BAM Data Multiplexer provides access to the network data channels
+ of modems integrated into many older Qualcomm SoCs, e.g. Qualcomm MSM8916
+ or MSM8974. It is built using a simple protocol layer on top of a DMA engine
+ (Qualcomm BAM DMA) and bidirectional interrupts to coordinate power control.
+
+ Note that this schema does not directly describe a hardware block but rather
+ a firmware convention that combines several other hardware blocks (such as the
+ DMA engine). As such it is specific to a firmware version, not a particular
+ SoC or hardware version.
+
+properties:
+ compatible:
+ const: qcom,bam-dmux
+
+ interrupts:
+ description:
+ Interrupts used by the modem to signal the AP.
+ Both interrupts must be declared as IRQ_TYPE_EDGE_BOTH.
+ items:
+ - description: Power control
+ - description: Power control acknowledgment
+
+ interrupt-names:
+ items:
+ - const: pc
+ - const: pc-ack
+
+ qcom,smem-states:
+ $ref: /schemas/types.yaml#/definitions/phandle-array
+ description: State bits used by the AP to signal the modem.
+ items:
+ - description: Power control
+ - description: Power control acknowledgment
+
+ qcom,smem-state-names:
+ description: Names for the state bits used by the AP to signal the modem.
+ items:
+ - const: pc
+ - const: pc-ack
+
+ dmas:
+ items:
+ - description: TX DMA channel phandle
+ - description: RX DMA channel phandle
+
+ dma-names:
+ items:
+ - const: tx
+ - const: rx
+
+required:
+ - compatible
+ - interrupts
+ - interrupt-names
+ - qcom,smem-states
+ - qcom,smem-state-names
+ - dmas
+ - dma-names
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/irq.h>
+
+ mpss: remoteproc {
+ bam-dmux {
+ compatible = "qcom,bam-dmux";
+
+ interrupt-parent = <&modem_smsm>;
+ interrupts = <1 IRQ_TYPE_EDGE_BOTH>, <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";
+ };
+ };
--
2.34.1