legacy_apps: Add README

Add instructions to fetch libraries and build legacy apps and tests.

Signed-off-by: Tanmay Shah <[email protected]>

examples/legacy_apps/README.md

@@ -0,0 +1,66 @@
+# Summary
+
+This directory contains legacy applications and tests examples.
+These applications were moved from open-amp repository.
+
+
+# Initialization
+
+The first step is to initialize the workspace folder (``my-workspace``) where
+the examples and all Zephyr modules will be cloned. You can do
+that by running:
+
+```shell
+# initialize my-workspace for the example-application (main branch)
+west init -m https://github.com/OpenAMP/openamp-system-reference --mf examples/legacy_apps/west.yml --mr main my-workspace
+# update modules
+cd my-workspace
+west update
+```
+
+# Build
+
+Following steps to build legacy apps on host machine.
+
+```
+export PROJECT_ROOT=$PWD
+```
+
+## Build libmetal
+```shell
+  $ cd $PROJECT_ROOT/libmetal
+  $ cmake . -Bbuild -DCMAKE_INSTALL_PREFIX=$PROJECT_ROOT/target
+  $ make -C build VERBOSE=1 install
+```
+
+## Build open_amp
+```shell
+  $ cd $PROJECT_ROOT/open-amp
+  $ cmake . -Bbuild -DCMAKE_INCLUDE_PATH=$PROJECT_ROOT/libmetal/build/lib/include/   -DCMAKE_LIBRARY_PATH=$PROJECT_ROOT/libmetal/build/lib/ -DCMAKE_INSTALL_PREFIX=$PROJECT_ROOT/target
+  $ make -C build VERBOSE=1 install
+```
+## Build legacy Apps
+```shell
+  $ cd $PROJECT_ROOT/openamp-system-reference/examples/legacy_apps
+  $ cmake -Bbuild \
+-DCMAKE_INCLUDE_PATH="$PROJECT_ROOT/libmetal/build/lib/include/;$PROJECT_ROOT/open-amp/build/lib/include/" \
+-DCMAKE_LIBRARY_PATH="$PROJECT_ROOT/libmetal/build/lib/;$PROJECT_ROOT/open-amp/build/lib/" \
+-DCMAKE_INSTALL_PREFIX=$PROJECT_ROOT/target
+  $ make -C build VERBOSE=1 install
+```
+
+## Run application on a Linux PC
+It is possible to run application on a Linux PC to communicate between two Linux processes.
+
+```shell
+  $ cd $PROJECT_ROOT/target
+  $ echo "################### run ping test #####################"
+  $ LD_LIBRARY_PATH=./lib  ./bin/rpmsg-echo-static &
+  $ sleep 1
+  $ LD_LIBRARY_PATH=./lib  ./bin//msg-test-rpmsg-ping-static 1
+
+  $ echo "################### run ping test #####################"
+  $ LD_LIBRARY_PATH=./lib  ./bin/rpmsg-nocopy-echo-static &
+  $ sleep 1
+  $ LD_LIBRARY_PATH=./lib  ./bin//rpmsg-nocopy-ping-static  1
+```