fit: Support compat string property in configuration node

This patch adds support for an optional optimization to compatible
string matching where the compatible string property from the root node
of the kernel FDT can be copied into the configuration node of the FIT
image. This is most useful when using compressed FDTs or when using FDT
overlays, where the traditional extraction of the compatible string from
the kernel FDT itself is not easily possible.

Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 73 insertions, 0 deletions

diff --git a/doc/uImage.FIT/kernel_fdts_compressed.its b/doc/uImage.FIT/kernel_fdts_compressed.its
new file mode 100644
index 0000000000..8f81106efc
--- /dev/null
+++ b/doc/uImage.FIT/kernel_fdts_compressed.its
@@ -0,0 +1,73 @@
+/*
+ * U-Boot uImage source file with a kernel and multiple compressed FDT blobs.
+ * Since the FDTs are compressed, configurations must provide a compatible
+ * string to match directly.
+ */
+
+/dts-v1/;
+
+/ {
+	description = "Image with single Linux kernel and compressed FDT blobs";
+	#address-cells = <1>;
+
+	images {
+		kernel {
+			description = "Vanilla Linux kernel";
+			data = /incbin/("./vmlinux.bin.gz");
+			type = "kernel";
+			arch = "ppc";
+			os = "linux";
+			compression = "gzip";
+			load = <00000000>;
+			entry = <00000000>;
+			hash-1 {
+				algo = "crc32";
+			};
+			hash-2 {
+				algo = "sha1";
+			};
+		};
+		fdt@1 {
+			description = "Flattened Device Tree blob 1";
+			data = /incbin/("./myboard-var1.dtb");
+			type = "flat_dt";
+			arch = "ppc";
+			compression = "gzip";
+			hash-1 {
+				algo = "crc32";
+			};
+			hash-2 {
+				algo = "sha1";
+			};
+		};
+		fdt@2 {
+			description = "Flattened Device Tree blob 2";
+			data = /incbin/("./myboard-var2.dtb");
+			type = "flat_dt";
+			arch = "ppc";
+			compression = "lzma";
+			hash-1 {
+				algo = "crc32";
+			};
+			hash-2 {
+				algo = "sha1";
+			};
+		};
+	};
+
+	configurations {
+		default = "conf@1";
+		conf@1 {
+			description = "Boot Linux kernel with FDT blob 1";
+			kernel = "kernel";
+			fdt = "fdt@1";
+			compatible = "myvendor,myboard-variant1";
+		};
+		conf@2 {
+			description = "Boot Linux kernel with FDT blob 2";
+			kernel = "kernel";
+			fdt = "fdt@2";
+			compatible = "myvendor,myboard-variant2";
+		};
+	};
+};