cmd: mtdparts: support runtime generated mtdparts

Some CPUs contains boot ROM code capable reading first few blocks
(where SPL resides) of NAND flash and executing it. It is wise to
create separate partition here for SPL. As block size depends on
NAND chip used, we could either use worst case (biggest) partition
size or base its size on actual block size. This patch adds support
for the latter option.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>

cmd/mtdparts.c

@@ -109,17 +109,17 @@ DECLARE_GLOBAL_DATA_PTR;
 #define MTD_WRITEABLE_CMD		1
 
 /* default values for mtdids and mtdparts variables */
-#if defined(MTDIDS_DEFAULT)
-static const char *const mtdids_default = MTDIDS_DEFAULT;
-#else
-static const char *const mtdids_default = NULL;
+#if !defined(MTDIDS_DEFAULT)
+#define MTDIDS_DEFAULT NULL
 #endif
-
-#if defined(MTDPARTS_DEFAULT)
-static const char *const mtdparts_default = MTDPARTS_DEFAULT;
-#else
-static const char *const mtdparts_default = NULL;
+#if !defined(MTDPARTS_DEFAULT)
+#define MTDPARTS_DEFAULT NULL
 #endif
+#if defined(CONFIG_SYS_MTDPARTS_RUNTIME)
+extern void board_mtdparts_default(const char **mtdids, const char **mtdparts);
+#endif
+static const char *mtdids_default = MTDIDS_DEFAULT;
+static const char *mtdparts_default = MTDPARTS_DEFAULT;
 
 /* copies of last seen 'mtdids', 'mtdparts' and 'partition' env variables */
 #define MTDIDS_MAXLEN		128
@@ -1725,6 +1725,9 @@ int mtdparts_init(void)
 		memset(last_ids, 0, MTDIDS_MAXLEN);
 		memset(last_parts, 0, MTDPARTS_MAXLEN);
 		memset(last_partition, 0, PARTITION_MAXLEN);
+#if defined(CONFIG_SYS_MTDPARTS_RUNTIME)
+		board_mtdparts_default(&mtdids_default, &mtdparts_default);
+#endif
 		use_defaults = 1;
 		initialized = 1;
 	}