boot/uboot: add support for i.MX28 NAND format

index 3f39ee8..1b3c17c 100644
@@ -129,6 +129,63 @@ config BR2_TARGET_UBOOT_FORMAT_SD
 
 	  See doc/README.mxs (or doc/README.mx28_common before 2013.07)
 
+config BR2_TARGET_UBOOT_FORMAT_NAND
+	depends on BR2_arm
+	bool "u-boot.nand"
+	help
+	  This is Freescale i.MX28 BootStream format (.sb), with a header
+	  for booting from a NAND flash.
+
+	  U-boot includes an mxsboot tool to generate this format,
+	  starting from 2011.12.
+
+	  There are two possibilities when preparing an image writable to
+	  NAND flash:
+	  1) The NAND was not written at all yet or the BCB (Boot Control
+	  Blocks) is broken. In this case, the NAND image 'u-boot.nand'
+	  needs to written.
+	  2) The NAND flash was already written with a good BCB. This
+	  applies after 'u-boot.nand' was correctly written. There is no
+	  need to write the BCB again. In this case, the bootloader can be
+	  upgraded by writing 'u-boot.sb'.
+
+	  To satisfy both cases, the 'u-boot.nand' image obtained from
+	  mxsboot as well as the U-Boot make target 'u-boot.sb' are copied
+	  to the binaries directory.
+
+	  See doc/README.mxs (or doc/README.mx28_common before 2013.07)
+
+if BR2_TARGET_UBOOT_FORMAT_NAND
+
+config BR2_TARGET_UBOOT_FORMAT_NAND_PAGE_SIZE
+	int "NAND page size"
+	default 2048
+	help
+	  The NAND page size of the targets NAND flash in bytes as a
+	  decimal integer value.
+
+	  The value provided here is passed to the -w option of mxsboot.
+
+config BR2_TARGET_UBOOT_FORMAT_NAND_OOB_SIZE
+	int "NAND OOB size"
+	default 64
+	help
+	  The NAND OOB size of the targets NAND flash in bytes as a
+	  decimal integer value.
+
+	  The value provided here is passed to the -o option of mxsboot.
+
+config BR2_TARGET_UBOOT_FORMAT_NAND_ERASE_SIZE
+	int "NAND erase size"
+	default 131072
+	help
+	  The NAND eraseblock size of the targets NAND flash in bytes as
+	  a decimal integer value.
+
+	  The value provided here is passed to the -e option of mxsboot.
+
+endif
+
 config BR2_TARGET_UBOOT_FORMAT_CUSTOM
 	bool "Custom (specify below)"
 	help

index 630619a..d9f4398 100644
@@ -54,6 +54,10 @@ else ifeq ($(BR2_TARGET_UBOOT_FORMAT_SD),y)
 UBOOT_BIN = u-boot.sd
 UBOOT_MAKE_TARGET = u-boot.sb
 UBOOT_DEPENDENCIES += host-elftosb
+else ifeq ($(BR2_TARGET_UBOOT_FORMAT_NAND),y)
+UBOOT_BIN = u-boot.nand
+UBOOT_MAKE_TARGET = u-boot.sb
+UBOOT_DEPENDENCIES += host-elftosb
 else ifeq ($(BR2_TARGET_UBOOT_FORMAT_CUSTOM),y)
 UBOOT_BIN = $(call qstrip,$(BR2_TARGET_UBOOT_FORMAT_CUSTOM_NAME))
 else

@@ -123,6 +127,12 @@ define UBOOT_BUILD_CMDS
 		$(UBOOT_MAKE_TARGET)
 	$(if $(BR2_TARGET_UBOOT_FORMAT_SD),
 		$(@D)/tools/mxsboot sd $(@D)/u-boot.sb $(@D)/u-boot.sd)
+	$(if $(BR2_TARGET_UBOOT_FORMAT_NAND),
+		$(@D)/tools/mxsboot \
+			-w $(BR2_TARGET_UBOOT_FORMAT_NAND_PAGE_SIZE)	\
+			-o $(BR2_TARGET_UBOOT_FORMAT_NAND_OOB_SIZE)	\
+			-e $(BR2_TARGET_UBOOT_FORMAT_NAND_ERASE_SIZE)	\
+			nand $(@D)/u-boot.sb $(@D)/u-boot.nand)
 endef
 
 define UBOOT_BUILD_OMAP_IFT

@@ -132,6 +142,8 @@ endef
 
 define UBOOT_INSTALL_IMAGES_CMDS
 	cp -dpf $(@D)/$(UBOOT_BIN) $(BINARIES_DIR)/
+	$(if $(BR2_TARGET_UBOOT_FORMAT_NAND),
+		cp -dpf $(@D)/$(UBOOT_MAKE_TARGET) $(BINARIES_DIR))
 	$(if $(BR2_TARGET_UBOOT_SPL),
 		cp -dpf $(@D)/$(call qstrip,$(BR2_TARGET_UBOOT_SPL_NAME)) $(BINARIES_DIR)/)
 	$(if $(BR2_TARGET_UBOOT_ENVIMAGE),