common: env_nand: Ensure that we have nand_info[0] prior to use

Now that nand_info[] is an array of pointers we need to ensure that it's
been populated prior to use.  We may for example have ENV in NAND set in
configurations that run on boards with and without NAND (where default
env is fine enough, such as omap3_beagle and beagleboard (NAND) vs
beagle xM (no NAND)).

Fixes: b616d9b0a7 ("nand: Embed mtd_info in struct nand_chip")
Cc: Scott Wood <oss@buserror.net>
Signed-off-by: Tom Rini <trini@konsulko.com>
Acked-by: Scott Wood <oss@buserror.net>

common/env_nand.c

@@ -163,6 +163,9 @@ static int erase_and_write_env(const struct env_location *location,
 {
 	int ret = 0;
 
+	if (!nand_info[0])
+		return 1;
+
 	printf("Erasing %s...\n", location->name);
 	if (nand_erase_opts(nand_info[0], &location->erase_opts))
 		return 1;
@@ -247,10 +250,10 @@ static int readenv(size_t offset, u_char *buf)
 	size_t blocksize, len;
 	u_char *char_ptr;
 
-	blocksize = nand_info[0]->erasesize;
-	if (!blocksize)
+	if (!nand_info[0])
 		return 1;
 
+	blocksize = nand_info[0]->erasesize;
 	len = min(blocksize, (size_t)CONFIG_ENV_SIZE);
 
 	while (amount_loaded < CONFIG_ENV_SIZE && offset < end) {
@@ -387,12 +390,12 @@ void env_relocate_spec(void)
 	ALLOC_CACHE_ALIGN_BUFFER(char, buf, CONFIG_ENV_SIZE);
 
 #if defined(CONFIG_ENV_OFFSET_OOB)
-	ret = get_nand_env_oob(nand_info[0], &nand_env_oob_offset);
 	/*
 	 * If unable to read environment offset from NAND OOB then fall through
 	 * to the normal environment reading code below
 	 */
-	if (!ret) {
+	if (nand_info[0] && !get_nand_env_oob(nand_info[0],
+					      &nand_env_oob_offset)) {
 		printf("Found Environment offset in OOB..\n");
 	} else {
 		set_default_env("!no env offset in OOB");