[U-Boot] [PATCH v3] cmd, fdt: add subcommand "get" to fdt header

[Heiko Schocher <hs@denx.de>]

store fdt header member with name <member> in U-Boot
Environment variable with name <var>.

for example to get the total length of the fdt and store
it in filesize, call:

fdt header get filesize totalsize

For membernames look into fdt header definition at
scripts/dtc/libfdt/libfdt.h

Signed-off-by: Heiko Schocher <hs@denx.de>
---

Changes in v3:
- add comments from Marek
  simplify for loop, use fdtp[i] -> drop ftdip++

Changes in v2:
- add obviously missing "static const char *"

 cmd/fdt.c | 40 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/cmd/fdt.c b/cmd/fdt.c
index 8a19a3fdbf..8bfa731a9e 100644
--- a/cmd/fdt.c
+++ b/cmd/fdt.c
@@ -73,6 +73,40 @@ static int fdt_value_env_set(const void *nodep, int len, const char *var)
 	return 0;
 }
 
+static const char * const fdt_member_table[] = {
+	"magic",
+	"totalsize",
+	"off_dt_struct",
+	"off_dt_strings",
+	"off_mem_rsvmap",
+	"version",
+	"last_comp_version",
+	"boot_cpuid_phys",
+	"size_dt_strings",
+	"size_dt_struct",
+};
+
+static int fdt_get_header_value(int argc, char * const argv[])
+{
+	fdt32_t *fdtp = (fdt32_t *)working_fdt;
+	ulong val;
+	int i;
+
+	if (argv[2][0] != 'g')
+		return CMD_RET_FAILURE;
+
+	for (i = 0; i < ARRAY_SIZE(fdt_member_table); i++) {
+		if (strcmp(fdt_member_table[i], argv[4]))
+			continue;
+
+		val = fdt32_to_cpu(fdtp[i]);
+		env_set_hex(argv[3], val);
+		return CMD_RET_SUCCESS;
+	}
+
+	return CMD_RET_FAILURE;
+}
+
 /*
  * Flattened Device Tree command, see the help for parameter definitions.
  */
@@ -491,6 +525,9 @@ static int do_fdt(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	 * Display header info
 	 */
 	} else if (argv[1][0] == 'h') {
+		if (argc == 5)
+			return fdt_get_header_value(argc, argv);
+
 		u32 version = fdt_version(working_fdt);
 		printf("magic:\t\t\t0x%x\n", fdt_magic(working_fdt));
 		printf("totalsize:\t\t0x%x (%d)\n", fdt_totalsize(working_fdt),
@@ -1090,7 +1127,8 @@ static char fdt_help_text[] =
 	"fdt set    <path> <prop> [<val>]    - Set <property> [to <val>]\n"
 	"fdt mknode <path> <node>            - Create a new node after <path>\n"
 	"fdt rm     <path> [<prop>]          - Delete the node or <property>\n"
-	"fdt header                          - Display header info\n"
+	"fdt header [get <var> <member>]     - Display header info\n"
+	"                                      get - get header member <member> and store it in <var>\n"
 	"fdt bootcpu <id>                    - Set boot cpuid\n"
 	"fdt memory <addr> <size>            - Add/Update memory node\n"
 	"fdt rsvmem print                    - Show current mem reserves\n"
-- 
2.17.2