minitests: Update Zephyr test's Makefiles and add README Signed-off-by: Tomasz Michalak <tmichalak@antmicro.com>

diff --git a/minitests/litex/zephyr/zcu104/README.md b/minitests/litex/zephyr/zcu104/README.md
new file mode 100644
index 0000000..351646d
--- /dev/null
+++ b/minitests/litex/zephyr/zcu104/README.md

@@ -0,0 +1,12 @@
+# Zephyr on Litex minitest
+
+This folder contains a minitest for Zephyr running on Litex SoC.
+
+## Synthesis+implementation
+
+There are two flows supported - Vivado only and Yosys-Vivado.
+In order to run them choose `make vivado` or `make yosys-vivado` respectively in the `src` directory.
+
+##Running the design on hardware
+
+In order to connect to the serial terminal use the baudrate rate of 115200.

diff --git a/minitests/litex/zephyr/zcu104/src/Makefile b/minitests/litex/zephyr/zcu104/src/Makefile
index 6776691..68bf326 100644
--- a/minitests/litex/zephyr/zcu104/src/Makefile
+++ b/minitests/litex/zephyr/zcu104/src/Makefile

@@ -1,2 +1,10 @@
 vivado:
 	python3 runme.py
+
+yosys-vivado:
+	mkdir -p build
+	cp mem* build/
+	env USE_YOSYS=1 python3 runme.py
+
+clean:
+	rm -rf build

diff --git a/minitests/litex/zephyr/zcu104/src/runme.py b/minitests/litex/zephyr/zcu104/src/runme.py
index 1286388..db071bf 100755
--- a/minitests/litex/zephyr/zcu104/src/runme.py
+++ b/minitests/litex/zephyr/zcu104/src/runme.py

@@ -18,15 +18,6 @@
     {'name': os.path.realpath('top.xdc'), 'file_type': 'xdc'},
 ]
 
-mem_init = [
-    {'name': os.path.realpath('mem.init'), 'file_type': 'init'},
-    {'name': os.path.realpath('mem_1.init'), 'file_type': 'init'},
-    {'name': os.path.realpath('mem_2.init'), 'file_type': 'init'},
-]
-
-if synth_tool == 'vivado':
-    files.extend(mem_init)
-
 tool = 'vivado'
 
 edam = {