bootstd: Add setup for the bootflow tests

We need to create a disk image with a partition table and a DOS-format
filesystem containing a few files. Provide a fallback binary for CI since
it does not seem able to detect the loopback partitions.

Add this to a dm_init test so that it happens when needed.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/py/tests/bootstd/mmc1.img.xz b/test/py/tests/bootstd/mmc1.img.xz
new file mode 100644
index 0000000..4e7f39b
--- /dev/null
+++ b/test/py/tests/bootstd/mmc1.img.xz
Binary files differ
diff --git a/test/py/tests/test_ut.py b/test/py/tests/test_ut.py
index 01c2b3f..35fb393 100644
--- a/test/py/tests/test_ut.py
+++ b/test/py/tests/test_ut.py
@@ -1,9 +1,102 @@
 # SPDX-License-Identifier: GPL-2.0
 # Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
 
+import gzip
+import os
 import os.path
 import pytest
 
+import u_boot_utils
+
+def mkdir_cond(dirname):
+    """Create a directory if it doesn't already exist
+
+    Args:
+        dirname: Name of directory to create
+    """
+    if not os.path.exists(dirname):
+        os.mkdir(dirname)
+
+def setup_bootflow_image(u_boot_console):
+    """Create a 20MB disk image with a single FAT partition"""
+    cons = u_boot_console
+    fname = os.path.join(cons.config.source_dir, 'mmc1.img')
+    mnt = os.path.join(cons.config.persistent_data_dir, 'mnt')
+    mkdir_cond(mnt)
+
+    u_boot_utils.run_and_log(cons, 'qemu-img create %s 20M' % fname)
+    u_boot_utils.run_and_log(cons, 'sudo sfdisk %s' % fname,
+                             stdin=b'type=c')
+
+    loop = None
+    mounted = False
+    complete = False
+    try:
+        out = u_boot_utils.run_and_log(cons,
+                                       'sudo losetup --show -f -P %s' % fname)
+        loop = out.strip()
+        fatpart = '%sp1' % loop
+        u_boot_utils.run_and_log(cons, 'sudo mkfs.vfat %s' % fatpart)
+        u_boot_utils.run_and_log(
+            cons, 'sudo mount -o loop %s %s -o uid=%d,gid=%d' %
+            (fatpart, mnt, os.getuid(), os.getgid()))
+        mounted = True
+
+        vmlinux = 'vmlinuz-5.3.7-301.fc31.armv7hl'
+        initrd = 'initramfs-5.3.7-301.fc31.armv7hl.img'
+        dtbdir = 'dtb-5.3.7-301.fc31.armv7hl'
+        script = '''# extlinux.conf generated by appliance-creator
+ui menu.c32
+menu autoboot Welcome to Fedora-Workstation-armhfp-31-1.9. Automatic boot in # second{,s}. Press a key for options.
+menu title Fedora-Workstation-armhfp-31-1.9 Boot Options.
+menu hidden
+timeout 20
+totaltimeout 600
+
+label Fedora-Workstation-armhfp-31-1.9 (5.3.7-301.fc31.armv7hl)
+        kernel /%s
+        append ro root=UUID=9732b35b-4cd5-458b-9b91-80f7047e0b8a rhgb quiet LANG=en_US.UTF-8 cma=192MB cma=256MB
+        fdtdir /%s/
+        initrd /%s''' % (vmlinux, dtbdir, initrd)
+        ext = os.path.join(mnt, 'extlinux')
+        mkdir_cond(ext)
+
+        with open(os.path.join(ext, 'extlinux.conf'), 'w') as fd:
+            print(script, file=fd)
+
+        inf = os.path.join(cons.config.persistent_data_dir, 'inf')
+        with open(inf, 'wb') as fd:
+            fd.write(gzip.compress(b'vmlinux'))
+        u_boot_utils.run_and_log(cons, 'mkimage -f auto -d %s %s' %
+                                 (inf, os.path.join(mnt, vmlinux)))
+
+        with open(os.path.join(mnt, initrd), 'w') as fd:
+            print('initrd', file=fd)
+
+        mkdir_cond(os.path.join(mnt, dtbdir))
+
+        dtb_file = os.path.join(mnt, '%s/sandbox.dtb' % dtbdir)
+        u_boot_utils.run_and_log(
+            cons, 'dtc -o %s' % dtb_file, stdin=b'/dts-v1/; / {};')
+        complete = True
+    except ValueError as exc:
+        print('Falled to create image, failing back to prepared copy: %s',
+              str(exc))
+    finally:
+        if mounted:
+            u_boot_utils.run_and_log(cons, 'sudo umount %s' % mnt)
+        if loop:
+            u_boot_utils.run_and_log(cons, 'sudo losetup -d %s' % loop)
+
+    if not complete:
+        # Use a prepared image since we cannot create one
+        infname = os.path.join(cons.config.source_dir,
+                               'test/py/tests/bootstd/mmc1.img.xz')
+        u_boot_utils.run_and_log(
+            cons,
+            ['sh', '-c', 'xz -dc %s >%s' % (infname, fname)])
+
+
 @pytest.mark.buildconfigspec('ut_dm')
 def test_ut_dm_init(u_boot_console):
     """Initialize data for ut dm tests."""
@@ -21,6 +114,16 @@
         with open(fn, 'wb') as fh:
             fh.write(data)
 
+@pytest.mark.buildconfigspec('cmd_bootflow')
+def test_ut_dm_init_bootstd(u_boot_console):
+    """Initialise data for bootflow tests"""
+
+    setup_bootflow_image(u_boot_console)
+
+    # Restart so that the new mmc1.img is picked up
+    u_boot_console.restart_uboot()
+
+
 def test_ut(u_boot_console, ut_subtest):
     """Execute a "ut" subtest.