tools: add support for setting the CSF into imximage

Add support for setting the CSF (Command Sequence File) pointer
which is used for HAB (High Assurance Boot) in the imximage by
adding e.g.

CSF 0x2000

in the imximage.cfg file.

This will set the CSF pointer accordingly just after the padded
data image area. The boot_data.length is adjusted with the
value from the imximage.cfg config file.

The resulting u-boot.imx can be signed with the FSL HAB tooling.
The generated CSF block needs to be appended to the u-boot.imx.

Signed-off-by: Stefano Babic <sbabic@denx.de>

2 files changed, 75 insertions, 3 deletions

diff --git a/doc/README.imximage b/doc/README.imximage
index 802eb90..dcda200 100644
--- a/doc/README.imximage
+++ b/doc/README.imximage
@@ -15,9 +15,6 @@ Booting from NOR flash does not require to use this image type.
 For more details refer Chapter 2 - System Boot and section 2.14
 (flash header description) of the processor's manual.
 
-This implementation does not use at the moment the secure boot feature
-of the processor. The image is generated disabling all security fields.
-
 Command syntax:
 --------------
 ./tools/mkimage -l <mx u-boot_file>
@@ -86,6 +83,33 @@ Configuration command line syntax:
 				Example:
 				BOOT_FROM spi
 
+	CSF			value
+
+				Total size of CSF (Command Sequence File)
+				used for Secure Boot/ High Assurance Boot
+				(HAB).
+
+				Using this command will populate the IVT
+				(Initial Vector Table) CSF pointer and adjust
+				the length fields only. The CSF itself needs
+				to be generated with Freescale tools and
+				'manually' appended to the u-boot.imx file.
+
+				The CSF is then simply concatenated
+				to the u-boot image, making a signed bootloader,
+				that the processor can verify
+				if the fuses for the keys are burned.
+
+				Further infos how to configure the SOC to verify
+				the bootloader can be found in the "High
+				Assurance Boot Version Application Programming
+				Interface Reference Manual" as part of the
+				Freescale Code Signing Tool, available on the
+				manufacturer's website.
+
+				Example:
+				CSF 0x2000
+
 	DATA			type address value
 
 				type: word=4, halfword=2, byte=1
diff --git a/doc/README.mxc_hab b/doc/README.mxc_hab
new file mode 100644
index 0000000..97f8b7d
--- /dev/null
+++ b/doc/README.mxc_hab
@@ -0,0 +1,48 @@
+High Assurance Boot (HAB) for i.MX6 CPUs
+
+To authenticate U-Boot only by the CPU there is no code required in
+U-Boot itself. However, the U-Boot image to be programmed into the
+boot media needs to be properly constructed, i.e. it must contain a
+proper Command Sequence File (CSF).
+
+The Initial Vector Table contains a pointer to the CSF. Please see
+doc/README.imximage for how to prepare u-boot.imx.
+
+The CSF itself is being generated by Freescale HAB tools.
+
+mkimage will output additional information about "HAB Blocks"
+which can be used in the Freescale tooling to authenticate U-Boot
+(entries in the CSF file).
+
+Image Type:   Freescale IMX Boot Image
+Image Ver:    2 (i.MX53/6 compatible)
+Data Size:    327680 Bytes = 320.00 kB = 0.31 MB
+Load Address: 177ff420
+Entry Point:  17800000
+HAB Blocks:   177ff400 00000000 0004dc00
+              ^^^^^^^^ ^^^^^^^^ ^^^^^^^^
+		|	|	   |
+		|	|	   -------- (1)
+		|	|
+		|	------------------- (2)
+		|
+		--------------------------- (3)
+
+(1)	Size of area in file u-boot.imx to sign
+	This area should include the IVT, the Boot Data the DCD
+	and U-Boot itself.
+(2)	Start of area in u-boot.imx to sign
+(3)	Start of area in RAM to authenticate
+
+CONFIG_SECURE_BOOT currently enables only an additional command
+'hab_status' in U-Boot to retrieve the HAB status and events. This
+can be useful while developing and testing HAB.
+
+Commands to generate a signed U-Boot using Freescale HAB tools:
+cst --o U-Boot_CSF.bin < U-Boot.CSF
+objcopy -I binary -O binary --pad-to 0x2000 --gap-fill=0x00 \
+	U-Boot_CSF.bin U-Boot_CSF_pad.bin
+cat u-boot.imx U-Boot_CSF_pad.bin > u-boot-signed.imx
+
+NOTE: U-Boot_CSF.bin needs to be padded to the value specified in
+the imximage.cfg file.