soc: qcom: Add device tree binding for SMEM

Add device tree binding documentation for the Qualcom Shared Memory
Manager.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Andy Gross <agross@codeaurora.org>

diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smem.txt b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.txt
new file mode 100644 (file)
index 0000000..9326cdf
--- /dev/null
+++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.txt
@@ -0,0 +1,57 @@
+Qualcomm Shared Memory Manager binding
+
+This binding describes the Qualcomm Shared Memory Manager, used to share data
+between various subsystems and OSes in Qualcomm platforms.
+
+- compatible:
+       Usage: required
+       Value type: <stringlist>
+       Definition: must be:
+                   "qcom,smem"
+
+- memory-region:
+       Usage: required
+       Value type: <prop-encoded-array>
+       Definition: handle to memory reservation for main SMEM memory region.
+
+- qcom,rpm-msg-ram:
+       Usage: required
+       Value type: <prop-encoded-array>
+       Definition: handle to RPM message memory resource
+
+- hwlocks:
+       Usage: required
+       Value type: <prop-encoded-array>
+       Definition: reference to a hwspinlock used to protect allocations from
+                   the shared memory
+
+= EXAMPLE
+The following example shows the SMEM setup for MSM8974, with a main SMEM region
+at 0xfa00000 and the RPM message ram at 0xfc428000:
+
+       reserved-memory {
+               #address-cells = <1>;
+               #size-cells = <1>;
+               ranges;
+
+               smem_region: smem@fa00000 {
+                       reg = <0xfa00000 0x200000>;
+                       no-map;
+               };
+       };
+
+       smem@fa00000 {
+               compatible = "qcom,smem";
+
+               memory-region = <&smem_region>;
+               qcom,rpm-msg-ram = <&rpm_msg_ram>;
+
+               hwlocks = <&tcsr_mutex 3>;
+       };
+
+       soc {
+               rpm_msg_ram: memory@fc428000 {
+                       compatible = "qcom,rpm-msg-ram";
+                       reg = <0xfc428000 0x4000>;
+               };
+       };