Merge branch '2022-05-02-add-verifying-program-loader'

To quote the author:

U-Boot provides a verified-boot feature based around FIT, but there is
no standard way of implementing it for a board. At present the various
required pieces must be built up separately, to produce a working
implementation. In particular, there is no built-in support for selecting
A/B boot or recovery mode.

This series introduces VPL, a verified program loader phase for U-Boot.
Its purpose is to run the verified-boot process and decide which SPL
binary should be run. It is critical that this decision happens before
SPL runs, since SPL sets up SDRAM and we need to be able to update the
SDRAM-init code in the field.

Adding VPL into the boot flow provides a standard place to implement
verified boot. This series includes the phase itself, some useful Kconfig
options and a sandbox_vpl build for sandbox. No verfied-boot support is
provided in this series.

Most of the patches in this series are fixes and improvements to docs and
various Kconfig conditions for SPL.

4 files changed, 59 insertions, 3 deletions

diff --git a/test/py/conftest.py b/test/py/conftest.py
index 16e445cd8e..2ba34479e0 100644
--- a/test/py/conftest.py
+++ b/test/py/conftest.py
@@ -322,8 +322,11 @@ def pytest_generate_tests(metafunc):
         if fn == 'ut_subtest':
             generate_ut_subtest(metafunc, fn, '/u-boot.sym')
             continue
-        if fn == 'ut_spl_subtest':
-            generate_ut_subtest(metafunc, fn, '/spl/u-boot-spl.sym')
+        m_subtest = re.match('ut_(.)pl_subtest', fn)
+        if m_subtest:
+            spl_name = m_subtest.group(1)
+            generate_ut_subtest(
+                metafunc, fn, f'/{spl_name}pl/u-boot-{spl_name}pl.sym')
             continue
         generate_config(metafunc, fn)
 
diff --git a/test/py/tests/test_help.py b/test/py/tests/test_help.py
index d50295e5bd..bac0a29f5a 100644
--- a/test/py/tests/test_help.py
+++ b/test/py/tests/test_help.py
@@ -2,7 +2,21 @@
 # Copyright (c) 2015 Stephen Warren
 # Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
 
+import pytest
+
 def test_help(u_boot_console):
     """Test that the "help" command can be executed."""
 
     u_boot_console.run_command('help')
+
+@pytest.mark.boardspec('sandbox_vpl')
+def test_vpl_help(u_boot_console):
+    try:
+        cons = u_boot_console
+        cons.restart_uboot()
+        cons.run_command('help')
+        output = cons.get_spawn_output().replace('\r', '')
+        assert 'print command description/usage' in output
+    finally:
+        # Restart afterward to get the normal device tree back
+        u_boot_console.restart_uboot()
diff --git a/test/py/tests/test_vpl.py b/test/py/tests/test_vpl.py
new file mode 100644
index 0000000000..4af578b917
--- /dev/null
+++ b/test/py/tests/test_vpl.py
@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright 2022 Google LLC
+# Written by Simon Glass <sjg@chromium.org>
+
+import os.path
+import pytest
+
+def test_vpl(u_boot_console, ut_vpl_subtest):
+    """Execute a "ut" subtest.
+
+    The subtests are collected in function generate_ut_subtest() from linker
+    generated lists by applying a regular expression to the lines of file
+    vpl/u-boot-vpl.sym. The list entries are created using the C macro
+    UNIT_TEST().
+
+    Strict naming conventions have to be followed to match the regular
+    expression. Use UNIT_TEST(foo_test_bar, _flags, foo_test) for a test bar in
+    test suite foo that can be executed via command 'ut foo bar' and is
+    implemented in C function foo_test_bar().
+
+    Args:
+        u_boot_console (ConsoleBase): U-Boot console
+        ut_subtest (str): VPL test to be executed (e.g. 'dm platdata_phandle')
+    """
+    try:
+        cons = u_boot_console
+        cons.restart_uboot_with_flags(['-u', '-k', ut_vpl_subtest.split()[1]])
+        output = cons.get_spawn_output().replace('\r', '')
+        assert 'Failures: 0' in output
+    finally:
+        # Restart afterward in case a non-VPL test is run next. This should not
+        # happen since VPL tests are run in their own invocation of test.py, but
+        # the cost of doing this is not too great at present.
+        u_boot_console.restart_uboot()
diff --git a/test/py/u_boot_console_sandbox.py b/test/py/u_boot_console_sandbox.py
index ce4ca7e55e..cef416d738 100644
--- a/test/py/u_boot_console_sandbox.py
+++ b/test/py/u_boot_console_sandbox.py
@@ -43,7 +43,12 @@ class ConsoleSandbox(ConsoleBase):
 
         bcfg = self.config.buildconfig
         config_spl = bcfg.get('config_spl', 'n') == 'y'
-        fname = '/spl/u-boot-spl' if config_spl else '/u-boot'
+        config_vpl = bcfg.get('config_vpl', 'n') == 'y'
+        if config_vpl:
+            # Run TPL first, which runs VPL
+            fname = '/tpl/u-boot-tpl'
+        else:
+            fname = '/spl/u-boot-spl' if config_spl else '/u-boot'
         print(fname)
         cmd = []
         if self.config.gdbserver: