[U-Boot] [PATCH 3/5] nand: sunxi: Add secondary U-Boot offset on second syndrome partition

[Daniel Kochmański]

Introduces CONFIG_SYS_NAND_U_BOOT_BACKUP_OFFS, pointing to backup
U-Boot instance in nand memory. In case if first header doesn't match,
tries to load bootloader from this offset. In case of both failing,
hang() is called.

Additionally define offset of backup U-boot for sunxi at start of
second syndrome partition.

Signed-off-by: Daniel Kochmański <dkochmanski at turtle-solutions.eu>
Cc: Ian Campbell <ijc at hellion.org.uk>
Cc: Hans De Goede <hdegoede at redhat.com>
---

 README                         |  4 ++++
 common/spl/spl_nand.c          | 28 +++++++++++++++++++++++++---
 include/configs/sunxi-common.h |  1 +
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/README b/README
index ee65fdb..4ccf3cb 100644
--- a/README
+++ b/README
@@ -3722,6 +3722,10 @@ FIT uImage format:
 		CONFIG_SYS_NAND_U_BOOT_OFFS
 		Location in NAND to read U-Boot from
 
+		CONFIG_SYS_NAND_U_BOOT_BACKUP_OFFS
+		Location in NAND to read backup U-Boot from, if first
+		location doesn't contain valid image.
+
 		CONFIG_SYS_NAND_U_BOOT_DST
 		Location in memory to load U-Boot to
 
diff --git a/common/spl/spl_nand.c b/common/spl/spl_nand.c
index 9d59fbb..7c44de1 100644
--- a/common/spl/spl_nand.c
+++ b/common/spl/spl_nand.c
@@ -2,6 +2,9 @@
  * Copyright (C) 2011
  * Corscience GmbH & Co. KG - Simon Schwarz <schwarz at corscience.de>
  *
+ * Copyright (C) 2015
+ * Turtle Solutions - Daniel Kochmański <dkochmanski at turtle-solutions.eu>
+ *
  * SPDX-License-Identifier:	GPL-2.0+
  */
 #include <common.h>
@@ -90,9 +93,28 @@ void spl_nand_load_image(void)
 	nand_spl_load_image(CONFIG_SYS_NAND_U_BOOT_OFFS,
 			    sizeof(*header), (void *)header);
 	spl_parse_image_header(header);
-	nand_spl_load_image(CONFIG_SYS_NAND_U_BOOT_OFFS,
-			    spl_image.size,
-			    (void *)(unsigned long)spl_image.load_addr);
+	if (header->ih_os == IH_OS_U_BOOT) {
+		nand_spl_load_image(CONFIG_SYS_NAND_U_BOOT_OFFS,
+				    spl_image.size,
+				    (void *)(unsigned long)spl_image.load_addr);
+		nand_deselect();
+		return;
+	}
+	puts("U-boot header didn't match.\n");
+#ifdef CONFIG_SYS_NAND_U_BOOT_BACKUP_OFFS
+	puts("Trying to start backup u-boot now...\n");
+	nand_spl_load_image(CONFIG_SYS_NAND_U_BOOT_BACKUP_OFFS,
+			    sizeof(*header), (void *)header);
+	spl_parse_image_header(header);
+	if (header->ih_os == IH_OS_U_BOOT) {
+		nand_spl_load_image(CONFIG_SYS_NAND_U_BOOT_BACKUP_OFFS,
+				    spl_image.size,
+				    (void *)(unsigned long)spl_image.load_addr);
+		nand_deselect();
+		return;
+	}
+#endif
+	puts("No valid u-boot image found.\n");
 	nand_deselect();
 }
 #endif
diff --git a/include/configs/sunxi-common.h b/include/configs/sunxi-common.h
index b40cdd3..15fe512 100644
--- a/include/configs/sunxi-common.h
+++ b/include/configs/sunxi-common.h
@@ -330,6 +330,7 @@ extern int soft_i2c_gpio_scl;
 #define CONFIG_NAND_SUNXI
 #define CONFIG_CMD_SPL_WRITE_SIZE		0x000400
 #define CONFIG_SYS_NAND_U_BOOT_OFFS		0x008000
+#define CONFIG_SYS_NAND_U_BOOT_BACKUP_OFFS	0x208000
 #endif /* CONFIG_SPL_NAND_SUPPORT */
 
 #define CONFIG_MISC_INIT_R
-- 
2.3.6