--- zzzz-none-000/linux-4.4.271/drivers/mtd/cmdlinepart.c	2021-06-03 06:22:09.000000000 +0000
+++ dakota-7530ac-750/linux-4.4.271/drivers/mtd/cmdlinepart.c	2023-01-11 09:25:42.000000000 +0000
@@ -46,6 +46,22 @@
  *
  * 1 NOR Flash with 2 partitions, 1 NAND with one
  * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
+ *
+ * ==========================================================================
+ * AVM extensions
+ * --------------
+ *
+ *  A new command line parameter 'mtdparts_ext' was introduced with
+ *  same format as 'mtdparts' above.
+ *
+ *  The semantics of 'mtdparts' force a complete override of previously
+ *  given parameters in case another 'mtdparts' entry is found.
+ *
+ *  All 'mtdparts_ext' entries however are appended.
+ *  When the parser kicks in the first time, the kernel's 'mtdparts'
+ *  is appended to the 'mtdparts_ext' collection, so that the system is fed
+ *  with the complete information.
+ * ==========================================================================
  */
 
 #define pr_fmt(fmt)	"mtd: " fmt
@@ -83,6 +99,9 @@
 static char *mtdparts;
 static char *cmdline;
 static int cmdline_parsed;
+#define AVM_MAX_MTDPARTS_EXT 64
+static const char *avm_cmdline_ext[AVM_MAX_MTDPARTS_EXT + 1] __maybe_unused;
+static unsigned int num_avm_cmdline_ext __maybe_unused;
 
 /*
  * Parse one partition definition for an MTD. Since there can be many
@@ -216,6 +235,51 @@
 	return parts;
 }
 
+#ifdef CONFIG_MTD_CMDLINE_PARTS_EXT
+static char *mtdpart_ext_build_cmdline(void)
+{
+	char *cmdline_joined;
+	unsigned int arg_n;
+	size_t len;
+
+	if (cmdline)
+		avm_cmdline_ext[num_avm_cmdline_ext++] = cmdline;
+
+	if (num_avm_cmdline_ext == 0)
+		return NULL;
+
+	len = 0;
+	for (arg_n = 0; arg_n < num_avm_cmdline_ext; ++arg_n)
+		len += strlen(avm_cmdline_ext[arg_n]);
+
+	/* Reserve room for added ';' */
+	len += num_avm_cmdline_ext - 1;
+
+	cmdline_joined = kzalloc(len + 1, GFP_KERNEL);
+	if (!cmdline_joined)
+		return ERR_PTR(-ENOMEM);
+
+	for (arg_n = 0; arg_n < num_avm_cmdline_ext; ++arg_n) {
+		if (arg_n)
+			strcat(cmdline_joined, ";");
+		strcat(cmdline_joined, avm_cmdline_ext[arg_n]);
+	}
+
+	return cmdline_joined;
+}
+
+static int __init mtdpart_setup_ext(char *s)
+{
+	if (num_avm_cmdline_ext < AVM_MAX_MTDPARTS_EXT)
+		avm_cmdline_ext[num_avm_cmdline_ext++] = s;
+	else
+		pr_err("Too many mtdparts_ext arguments, discarding arg \"%s\"\n",
+				s);
+	return 1;
+}
+__setup("mtdparts_ext=", mtdpart_setup_ext);
+#endif
+
 /*
  * Parse the command line.
  */
@@ -343,7 +407,18 @@
 
 	/* parse command line */
 	if (!cmdline_parsed) {
-		err = mtdpart_setup_real(cmdline);
+		char *ext_cmdline = cmdline;
+
+#ifdef CONFIG_MTD_CMDLINE_PARTS_EXT
+		ext_cmdline = mtdpart_ext_build_cmdline();
+		if (IS_ERR(ext_cmdline))
+			return PTR_ERR(ext_cmdline);
+#endif
+		err = mtdpart_setup_real(ext_cmdline);
+
+		if (ext_cmdline != cmdline)
+			kfree(ext_cmdline);
+
 		if (err)
 			return err;
 	}
@@ -407,7 +482,6 @@
 	cmdline = s;
 	return 1;
 }
-
 __setup("mtdparts=", mtdpart_setup);
 
 static struct mtd_part_parser cmdline_parser = {