drivers: smem: sandbox

Add Sandbox driver for SMEM. mostly stub operations.

Signed-off-by: Ramon Fried <ramon.fried@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/smem/Kconfig b/drivers/smem/Kconfig
index 6cf5a4e..7169d0f 100644
--- a/drivers/smem/Kconfig
+++ b/drivers/smem/Kconfig
@@ -3,6 +3,15 @@
 
 if SMEM
 
+config SANDBOX_SMEM
+    bool "Sandbox Shared Memory Manager (SMEM)"
+    depends on SANDBOX && DM
+    help
+      enable SMEM support for sandbox. This is an emulation of a real SMEM
+      manager.
+      The sandbox driver allocates a shared memory from the heap and
+      initialzies it on start.
+
 config MSM_SMEM
     bool "Qualcomm Shared Memory Manager (SMEM)"
     depends on DM