cmd: add FDT setup for bootelf by flag

Added the ability to use FDT for ELF applications, required to run some
OS. To make FDT setup, you need to set the -d fdt_addr_r cmd option for
bootelf command. Enable by selecting CMD_ELF_FDT_SETUP.

Signed-off-by: Maxim Moskalets <Maxim.Moskalets@kaspersky.com>

cmd/Kconfig

@@ -490,6 +490,17 @@ config CMD_ELF
 	help
 	  Boot an ELF/vxWorks image from the memory.
 
+config CMD_ELF_FDT_SETUP
+	bool "Flattened Device Tree setup in bootelf cmd"
+	default n
+	depends on CMD_ELF
+	select LIB_LIBFDT
+	select LMB
+	help
+	  Do FDT setup in bootelf command optionally by param -d, which
+	  allows to bring additional system info (e.g. /memory node) to
+	  the Operating System or application.
+
 config CMD_FDT
 	bool "Flattened Device Tree utility commands"
 	default y

cmd/elf.c

@@ -38,6 +38,10 @@ static unsigned long do_bootelf_exec(ulong (*entry)(int, char * const[]),
 /* Interpreter command to boot an arbitrary ELF image from memory */
 int do_bootelf(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 {
+#if CONFIG_IS_ENABLED(CMD_ELF_FDT_SETUP)
+	struct bootm_headers img = {0};
+	unsigned long fdt_addr = 0; /* Address of the FDT */
+#endif
 	unsigned long addr; /* Address of the ELF image */
 	unsigned long rc; /* Return value from user code */
 	char *sload = NULL;
@@ -46,13 +50,25 @@ int do_bootelf(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 	/* Consume 'bootelf' */
 	argc--; argv++;
 
-	/* Check for flag. */
+	/* Check for [-p|-s] flag. */
 	if (argc >= 1 && (argv[0][0] == '-' && \
 				(argv[0][1] == 'p' || argv[0][1] == 's'))) {
 		sload = argv[0];
 		/* Consume flag. */
 		argc--; argv++;
 	}
+
+#if CONFIG_IS_ENABLED(CMD_ELF_FDT_SETUP)
+	/* Check for [-d fdt_addr_r] option. */
+	if ((argc >= 2) && (argv[0][0] == '-') && (argv[0][1] == 'd')) {
+		if (strict_strtoul(argv[1], 16, &fdt_addr) != 0)
+			return CMD_RET_USAGE;
+		/* Consume option. */
+		argc -= 2;
+		argv += 2;
+	}
+#endif
+
 	/* Check for address. */
 	if (argc >= 1 && strict_strtoul(argv[0], 16, &addr) != -EINVAL) {
 		/* Consume address */
@@ -68,6 +84,16 @@ int do_bootelf(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 	else
 		addr = load_elf_image_shdr(addr);
 
+#if CONFIG_IS_ENABLED(CMD_ELF_FDT_SETUP)
+	if (fdt_addr) {
+		printf("## Setting up FDT at 0x%08lx ...\n", fdt_addr);
+		flush();
+
+		if (image_setup_libfdt(&img, (void *)fdt_addr, NULL))
+			return 1;
+	}
+#endif
+
 	if (!env_get_autostart())
 		return rcode;
 
@@ -298,9 +324,16 @@ int do_bootvx(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 U_BOOT_CMD(
 	bootelf, CONFIG_SYS_MAXARGS, 0, do_bootelf,
 	"Boot from an ELF image in memory",
-	"[-p|-s] [address]\n"
+	"[-p|-s] "
+#if CONFIG_IS_ENABLED(CMD_ELF_FDT_SETUP)
+	"[-d fdt_addr_r] "
+#endif
+	"[address]\n"
 	"\t- load ELF image at [address] via program headers (-p)\n"
-	"\t  or via section headers (-s)"
+	"\t  or via section headers (-s)\n"
+#if CONFIG_IS_ENABLED(CMD_ELF_FDT_SETUP)
+	"\t- setup FDT image at [fdt_addr_r] (-d)"
+#endif
 );
 
 U_BOOT_CMD(