[U-Boot] [PATCH v3] warp7: Fix U-Boot corruption after saving the environment

[Fabio Estevam <festevam@gmail.com>]

U-Boot binary has grown in such a way that it goes beyond the reserved
area for the environment variables.

Running "saveenv" followed by a "reset" causes U-Boot to hang because
of this overlap.

Fix this problem by selecting CONFIG_SYS_THUMB_BUILD=y, which
generates a smaller u-boot-dtb.imx binary.

Also, in order to prevent this same problem in the future, use
CONFIG_BOARD_SIZE_LIMIT, which will detect the overlap in build-time.

CONFIG_BOARD_SIZE_LIMIT does not accept math expressions, so declare
CONFIG_ENV_OFFSET with its direct value instead.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
---
Changes since v2:
- Select CONFIG_SYS_THUMB_BUILD=y (Tom)

 configs/warp7_defconfig |  1 +
 include/configs/warp7.h | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/configs/warp7_defconfig b/configs/warp7_defconfig
index 72cdb684a7..781cbe12d7 100644
--- a/configs/warp7_defconfig
+++ b/configs/warp7_defconfig
@@ -1,4 +1,5 @@
 CONFIG_ARM=y
+CONFIG_SYS_THUMB_BUILD=y
 CONFIG_ARCH_MX7=y
 CONFIG_SYS_TEXT_BASE=0x87800000
 CONFIG_TARGET_WARP7=y
diff --git a/include/configs/warp7.h b/include/configs/warp7.h
index 9a82581c5f..af278c617e 100644
--- a/include/configs/warp7.h
+++ b/include/configs/warp7.h
@@ -125,6 +125,19 @@
 #define CONFIG_SYS_INIT_SP_ADDR \
 	(CONFIG_SYS_INIT_RAM_ADDR + CONFIG_SYS_INIT_SP_OFFSET)
 
+/*
+ * Environment starts at CONFIG_ENV_OFFSET = 0x80000 = 512k
+ *
+ * Detect overlap between U-Boot image and environment area in build-time
+ *
+ * CONFIG_BOARD_SIZE_LIMIT = CONFIG_ENV_OFFSET - u-boot.imx offset
+ * CONFIG_BOARD_SIZE_LIMIT = 512k - 1k = 511k = 523264
+ *
+ * Currently CONFIG_BOARD_SIZE_LIMIT does not handle expressions, so
+ * write the direct value here
+ */
+#define CONFIG_BOARD_SIZE_LIMIT		523264
+
 /* I2C configs */
 #define CONFIG_SYS_I2C_MXC
 #define CONFIG_SYS_I2C_SPEED		100000
-- 
2.17.1