sandbox: Add a -T flag to use the test device tree

U-Boot already supports using -D to indicate that it should use the normal
device tree. It is sometimes useful to run with the test device tree, e.g.
when running a test. Add a -T option for this along with some
documentation.

It can be used like this:

   /tmp/b/sandbox/u-boot -T -c "ut dm pci_busdev"

(this will use /tmp/b/sandbox/arch/sandbox/dts/test.dtb as the DT)

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/doc/arch/sandbox.rst b/doc/arch/sandbox.rst
index 5c0caebcbf..54933b5675 100644
--- a/doc/arch/sandbox.rst
+++ b/doc/arch/sandbox.rst
@@ -103,6 +103,8 @@ A device tree binary file can be provided with -d. If you edit the source
 (it is stored at arch/sandbox/dts/sandbox.dts) you must rebuild U-Boot to
 recreate the binary file.
 
+To use the default device tree, use -D. To use the test device tree, use -T.
+
 To execute commands directly, use the -c option. You can specify a single
 command, or multiple commands separated by a semicolon, as is normal in
 U-Boot. Be careful with quoting as the shell will normally process and
@@ -499,6 +501,13 @@ run natively on your board if desired (and enabled).
 
 To run all tests use "make check".
 
+To run a single test in an existing sandbox build, you can use -T to use the
+test device tree, and -c to select the test:
+
+  /tmp/b/sandbox/u-boot -T -c "ut dm pci_busdev"
+
+This runs dm_test_pci_busdev() which is in test/dm/pci.c
+
 
 Memory Map
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