fdt: Add option to default to most compatible conf in a fit image

When booting a fit image with multiple configurations, the user either has to
specify which configuration to use explicitly, or there has to be a default
defined which is chosen automatically. This change adds an option to change
that behavior so that a configuration can be selected explicitly, or the
configuration which has the device tree that claims to be compatible with the
earliest item in U-Boot's device tree.

In other words, if U-Boot claimed to be compatible with A, B, and then C, and
the configurations claimed to be compatible with A, D and B, D and D, E, the
first configuration, A, D, would be chosen. Both the first and second
configurations match, but the first one matches a more specific entry in
U-Boot's device tree. The order in the kernel's device tree is ignored.

Signed-off-by: Gabe Black <gabeblack@google.com>

Commit-Ready: Gabe Black <gabeblack@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c
index d256ddfaa6..4dbe952bb0 100644
--- a/common/cmd_bootm.c
+++ b/common/cmd_bootm.c
@@ -949,8 +949,19 @@ static void *boot_get_kernel(cmd_tbl_t *cmdtp, int flag, int argc,
 			 * node
 			 */
 			bootstage_mark(BOOTSTAGE_ID_FIT_NO_UNIT_NAME);
+#ifdef CONFIG_FIT_BEST_MATCH
+			if (fit_uname_config)
+				cfg_noffset =
+					fit_conf_get_node(fit_hdr,
+							  fit_uname_config);
+			else
+				cfg_noffset =
+					fit_conf_find_compat(fit_hdr,
+							     gd->fdt_blob);
+#else
 			cfg_noffset = fit_conf_get_node(fit_hdr,
 							fit_uname_config);
+#endif
 			if (cfg_noffset < 0) {
 				bootstage_error(BOOTSTAGE_ID_FIT_NO_UNIT_NAME);
 				return NULL;