cmd: add "showlayout" command to get available mtd layouts in fdt

uboot-mtk-20220606/cmd/Kconfig

@@ -2600,5 +2600,10 @@ config CMD_GL_BTN
 	bool "GL-iNet button check command"
 	depends on BUTTON
 	default n
+
+config CMD_SHOW_MTD_LAYOUT
+	bool "Show mtd layout command"
+	depends on OF_LIBFDT
+	default n
 endmenu
 

uboot-mtk-20220606/cmd/Makefile

@@ -210,6 +210,8 @@ obj-$(CONFIG_CMD_SCP03) += scp03.o
 
 obj-$(CONFIG_CMD_GL_BTN) += glbtn.o
 
+obj-$(CONFIG_CMD_SHOW_MTD_LAYOUT) += showlayout.o
+
 obj-$(CONFIG_ARM) += arm/
 obj-$(CONFIG_RISCV) += riscv/
 obj-$(CONFIG_SANDBOX) += sandbox/

uboot-mtk-20220606/cmd/showlayout.c

@@ -0,0 +1,30 @@
+#include <common.h>
+#include <command.h>
+#include <dm/ofnode.h>
+
+
+static int do_showlayout(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
+{
+    ofnode node, layout;
+
+    node = ofnode_path("/mtd-layout");
+
+    if (ofnode_valid(node) && ofnode_get_child_count(node)) {
+        ofnode_for_each_subnode(layout, node) {
+            printf("mtd label: %s, mtdids: %s, mtdparts: %s\n", 
+                ofnode_read_string(layout, "label"), 
+                ofnode_read_string(layout, "mtdids"), 
+                ofnode_read_string(layout, "mtdparts"));
+        }
+    } else {
+        printf("get mtd layout failed!\n");
+    }
+    
+    return CMD_RET_SUCCESS;
+}
+
+U_BOOT_CMD(
+	showlayout, 2, 0, do_showlayout,
+	"Show mtd layout",
+	""
+);