scripts/lib/bsp/engine.py: add yocto_layer_create()

Add a new yocto_layer_create() function that will be used to generate
a generic yocto layer (for the new 'yocto-layer' command).

(From meta-yocto rev: 44acd01bf47c2e0a777e686c9339a6ff951fc972)

Signed-off-by: Tom Zanussi <tom.zanussi@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/lib/bsp/engine.py

@@ -1352,6 +1352,62 @@ def expand_targets(context, bsp_output_dir):
     return target_files
 
 
+def yocto_layer_create(layer_name, scripts_path, layer_output_dir, codedump, properties_file):
+    """
+    Create yocto layer
+
+    layer_name - user-defined layer name
+    scripts_path - absolute path to yocto /scripts dir
+    bsp_output_dir - dirname to create for BSP
+    codedump - dump generated code to bspgen.out
+    properties_file - use values from here if nonempty i.e no prompting
+
+    arch - the arch for a generic layer is 'generic-layer', defined in
+           scripts/lib/bsp/substrate/target/generic-layer
+    """
+    if os.path.exists(bsp_output_dir):
+        print "\nBSP output dir already exists, exiting. (%s)" % bsp_output_dir
+        sys.exit(1)
+
+    properties = None
+
+    if properties_file:
+        try:
+            infile = open(properties_file, "r")
+        except IOError:
+            print "Couldn't open properties file %s for reading, exiting" % properties_file
+            sys.exit(1)
+
+        properties = json.load(infile)
+
+    os.mkdir(bsp_output_dir)
+
+    context = create_context(machine, arch, scripts_path)
+    target_files = expand_targets(context, bsp_output_dir)
+
+    input_lines = gather_inputlines(target_files)
+
+    program_lines = []
+
+    gen_program_header_lines(program_lines)
+
+    gen_initial_property_vals(input_lines, program_lines)
+
+    if properties:
+        gen_supplied_property_vals(properties, program_lines)
+
+    gen_program_machine_lines(machine, program_lines)
+
+    if not properties:
+        gen_program_input_lines(input_lines, program_lines, context)
+
+    gen_program_lines(target_files, program_lines)
+
+    run_program_lines(program_lines, codedump)
+
+    print "New %s BSP created in %s" % (arch, bsp_output_dir)
+
+
 def yocto_bsp_create(machine, arch, scripts_path, bsp_output_dir, codedump, properties_file):
     """
     Create bsp