binman: build_from_git: Add optional make path inside git repo

Add optional argument make_path to build_from git. The new argument
allows specifying the path to a Makefile in case it is not in the root
of the git repo.
Also adjust the corresponding test.

Signed-off-by: Leonard Anderweit <l.anderweit@phytec.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

tools/binman/bintool.py

@@ -329,7 +329,7 @@ class Bintool:
 
     @classmethod
     def build_from_git(cls, git_repo, make_targets, bintool_path,
-            flags=None, git_branch=None):
+            flags=None, git_branch=None, make_path=None):
         """Build a bintool from a git repo
 
         This clones the repo in a temporary directory, builds it with 'make',
@@ -343,6 +343,8 @@ class Bintool:
                 build is complete
             flags (list of str): Flags or variables to pass to make, or None
             git_branch (str): Branch of git repo, or None to use the default
+            make_path (str): Relative path inside git repo containing the
+                Makefile, or None
 
         Returns:
             tuple:
@@ -359,7 +361,10 @@ class Bintool:
             tools.run('git', 'clone', '--depth', '1', git_repo, tmpdir)
         for target in make_targets:
             print(f"- build target '{target}'")
-            cmd = ['make', '-C', tmpdir, '-j', f'{multiprocessing.cpu_count()}',
+            makedir = tmpdir
+            if make_path:
+                makedir = os.path.join(tmpdir, make_path)
+            cmd = ['make', '-C', makedir, '-j', f'{multiprocessing.cpu_count()}',
                    target]
             if flags:
                 cmd += flags

tools/binman/bintool_test.py

@@ -303,6 +303,7 @@ class TestBintool(unittest.TestCase):
                 # See Bintool.build_from_git()
                 tmpdir = cmd[2]
                 self.fname = os.path.join(tmpdir, 'pathname')
+                os.makedirs(os.path.dirname(tmpdir), exist_ok=True)
                 tools.write_file(self.fname, b'hello')
 
         expected = b'this is a test'