dt-binding: soc: qcom: Add binding for rmtfs memory

This adds the binding for describing shared memory used to exchange file
system blocks between the RMTFS client and service. A client for this is
generally found in the modem firmware and is used for accessing
persistent storage for things such as radio calibration.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>

diff --git a/Documentation/devicetree/bindings/reserved-memory/qcom,rmtfs-mem.txt b/Documentation/devicetree/bindings/reserved-memory/qcom,rmtfs-mem.txt
new file mode 100644 (file)
index 0000000..8562ba1
--- /dev/null
+++ b/Documentation/devicetree/bindings/reserved-memory/qcom,rmtfs-mem.txt
@@ -0,0 +1,51 @@
+Qualcomm Remote File System Memory binding
+
+This binding describes the Qualcomm remote filesystem memory, which serves the
+purpose of describing the shared memory region used for remote processors to
+access block device data using the Remote Filesystem protocol.
+
+- compatible:
+       Usage: required
+       Value type: <stringlist>
+       Definition: must be:
+                   "qcom,rmtfs-mem"
+
+- reg:
+       Usage: required for static allocation
+       Value type: <prop-encoded-array>
+       Definition: must specify base address and size of the memory region,
+                   as described in reserved-memory.txt
+
+- size:
+       Usage: required for dynamic allocation
+       Value type: <prop-encoded-array>
+       Definition: must specify a size of the memory region, as described in
+                   reserved-memory.txt
+
+- qcom,client-id:
+       Usage: required
+       Value type: <u32>
+       Definition: identifier of the client to use this region for buffers.
+
+- qcom,vmid:
+       Usage: optional
+       Value type: <u32>
+       Definition: vmid of the remote processor, to set up memory protection.
+
+= EXAMPLE
+The following example shows the remote filesystem memory setup for APQ8016,
+with the rmtfs region for the Hexagon DSP (id #1) located at 0x86700000.
+
+       reserved-memory {
+               #address-cells = <2>;
+               #size-cells = <2>;
+               ranges;
+
+               rmtfs@86700000 {
+                       compatible = "qcom,rmtfs-mem";
+                       reg = <0x0 0x86700000 0x0 0xe0000>;
+                       no-map;
+
+                       qcom,client-id = <1>;
+               };
+       };