[U-Boot] [PATCH v2 3/7] spl: nand: support redundant u-boot image

Boris Brezillon
2016-06-01T11:23:20Z

On modern NAND it's more than recommended to have a backup copy of the
u-boot binary to recover from corruption: bitflips are quite common on
MLC NANDs, and the read-disturbance will corrupt your u-boot partitition
more quickly than what you would see on an SLC NAND.

Add an extra Kconfig option to specify the offset of the redundant u-boot
image.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
---
common/spl/spl_nand.c | 8 ++++++++
drivers/mtd/nand/Kconfig | 6 ++++++
2 files changed, 14 insertions(+)

diff --git a/common/spl/spl_nand.c b/common/spl/spl_nand.c
index 612bd4a..0bf0848 100644
--- a/common/spl/spl_nand.c
+++ b/common/spl/spl_nand.c
@@ -12,6 +12,9 @@

#ifndef CONFIG_SYS_NAND_U_BOOT_OFFS
#define CONFIG_SYS_NAND_U_BOOT_OFFS CONFIG_SPL_NAND_U_BOOT_OFFS
+#define CONFIG_SYS_NAND_U_BOOT_OFFS_REDUND CONFIG_SPL_NAND_U_BOOT_OFFS_REDUND
+#else
+#define CONFIG_SYS_NAND_U_BOOT_OFFS_REDUND CONFIG_SYS_NAND_U_BOOT_OFFS
#endif

#if defined(CONFIG_SPL_NAND_RAW_ONLY)
@@ -111,6 +114,11 @@ int spl_nand_load_image(void)
#endif
/* Load u-boot */
err = spl_nand_load_element(CONFIG_SYS_NAND_U_BOOT_OFFS, header);
+#if CONFIG_SYS_NAND_U_BOOT_OFFS != CONFIG_SYS_NAND_U_BOOT_OFFS_REDUND
+ if (err)
+ err = spl_nand_load_element(CONFIG_SYS_NAND_U_BOOT_OFFS_REDUND,
+ header);
+#endif
nand_deselect();
return err;
}
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 4b0f92c..2f1d1f7 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -110,6 +110,12 @@ config SPL_NAND_U_BOOT_OFFS
Set the offset from the start of the nand where u-boot should be
loaded from.

+config SPL_NAND_U_BOOT_OFFS_REDUND
+ hex "Location in NAND to read U-Boot from"
+ default SPL_NAND_U_BOOT_OFFS
+ help
+ Set the offset from the start of the nand where u-boot should be
+ loaded from.

config SPL_NAND_DENALI
bool "Support Denali NAND controller for SPL"
--
2.7.4