kernel: Add basic fitImage support

This patch adds support for generating a kernel fitImage, which is
a a successor to the uImage format. Unlike uImage, which could only
contain the kernel image itself, the fitImage can contain all kinds
of artifacts, like the kernel image, device tree blobs, initramfs
images, binary firmwares etc. Furthermore, the fitImage supports
different kinds of checksums, not only CRC32 like the uImage did.
Last, but not least, fitImage supports signatures such that either
the whole image or it's parts can be signed and then in turn can
be verified by the bootloader.

So far we only add support for wrapping the kernel image and DTB
into the fitImage. The fitImage uses the sha1 checksum, which is
the default.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Richard Purdie <richard.purdie@linuxfoundation.org>
Cc: Koen Kooi <koen@dominion.thruhere.net>
Cc: Paul Eggleton <paul.eggleton@linux.intel.com>
Cc: Ross Burton <ross.burton@intel.com>
Cc: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 234 insertions, 0 deletions

diff --git a/meta/classes/kernel-fitimage.bbclass b/meta/classes/kernel-fitimage.bbclass
new file mode 100644
index 0000000000..2a56a54516
--- /dev/null
+++ b/meta/classes/kernel-fitimage.bbclass
@@ -0,0 +1,234 @@
+inherit kernel-uboot
+
+python __anonymous () {
+    kerneltype = d.getVar('KERNEL_IMAGETYPE', True)
+    if kerneltype == 'fitImage':
+        depends = d.getVar("DEPENDS", True)
+        depends = "%s u-boot-mkimage-native dtc-native" % depends
+        d.setVar("DEPENDS", depends)
+
+	# Override KERNEL_IMAGETYPE_FOR_MAKE variable, which is internal
+	# to kernel.bbclass . We have to override it, since we pack zImage
+	# (at least for now) into the fitImage .
+        d.setVar("KERNEL_IMAGETYPE_FOR_MAKE", "zImage")
+
+        image = d.getVar('INITRAMFS_IMAGE', True)
+        if image:
+            d.appendVarFlag('do_assemble_fitimage', 'depends', ' ${INITRAMFS_IMAGE}:do_rootfs')
+}
+
+#
+# Emit the fitImage ITS header
+#
+fitimage_emit_fit_header() {
+	cat << EOF >> fit-image.its
+/dts-v1/;
+
+/ {
+        description = "U-Boot fitImage for ${DISTRO_NAME}/${PV}/${MACHINE}";
+        #address-cells = <1>;
+EOF
+}
+
+#
+# Emit the fitImage section bits
+#
+# $1 ... Section bit type: imagestart - image section start
+#                          confstart  - configuration section start
+#                          sectend    - section end
+#                          fitend     - fitimage end
+#
+fitimage_emit_section_maint() {
+	case $1 in
+	imagestart)
+		cat << EOF >> fit-image.its
+
+        images {
+EOF
+	;;
+	confstart)
+		cat << EOF >> fit-image.its
+
+        configurations {
+EOF
+	;;
+	sectend)
+		cat << EOF >> fit-image.its
+	};
+EOF
+	;;
+	fitend)
+		cat << EOF >> fit-image.its
+};
+EOF
+	;;
+	esac
+}
+
+#
+# Emit the fitImage ITS kernel section
+#
+# $1 ... Image counter
+# $2 ... Path to kernel image
+# $3 ... Compression type
+fitimage_emit_section_kernel() {
+
+	kernel_csum="sha1"
+
+	ENTRYPOINT=${UBOOT_ENTRYPOINT}
+	if test -n "${UBOOT_ENTRYSYMBOL}"; then
+		ENTRYPOINT=`${HOST_PREFIX}nm ${S}/vmlinux | \
+			awk '$3=="${UBOOT_ENTRYSYMBOL}" {print $1}'`
+	fi
+
+	cat << EOF >> fit-image.its
+                kernel@${1} {
+                        description = "Linux kernel";
+                        data = /incbin/("${2}");
+                        type = "kernel";
+                        arch = "${UBOOT_ARCH}";
+                        os = "linux";
+                        compression = "${3}";
+                        load = <${UBOOT_LOADADDRESS}>;
+                        entry = <${ENTRYPOINT}>;
+                        hash@1 {
+                                algo = "${kernel_csum}";
+                        };
+                };
+EOF
+}
+
+#
+# Emit the fitImage ITS DTB section
+#
+# $1 ... Image counter
+# $2 ... Path to DTB image
+fitimage_emit_section_dtb() {
+
+	dtb_csum="sha1"
+
+	cat << EOF >> fit-image.its
+                fdt@${1} {
+                        description = "Flattened Device Tree blob";
+                        data = /incbin/("${2}");
+                        type = "flat_dt";
+                        arch = "${UBOOT_ARCH}";
+                        compression = "none";
+                        hash@1 {
+                                algo = "${dtb_csum}";
+                        };
+                };
+EOF
+}
+
+#
+# Emit the fitImage ITS configuration section
+#
+# $1 ... Linux kernel ID
+# $2 ... DTB image ID
+fitimage_emit_section_config() {
+
+	conf_csum="sha1"
+
+	# Test if we have any DTBs at all
+	if [ -z "${2}" ] ; then
+		conf_desc="Boot Linux kernel"
+		fdt_line=""
+	else
+		conf_desc="Boot Linux kernel with FDT blob"
+		fdt_line="fdt = \"fdt@${2}\";"
+	fi
+	kernel_line="kernel = \"kernel@${1}\";"
+
+	cat << EOF >> fit-image.its
+                default = "conf@1";
+                conf@1 {
+                        description = "${conf_desc}";
+			${kernel_line}
+			${fdt_line}
+                        hash@1 {
+                                algo = "${conf_csum}";
+                        };
+                };
+EOF
+}
+
+do_assemble_fitimage() {
+	if test "x${KERNEL_IMAGETYPE}" = "xfitImage" ; then
+		kernelcount=1
+		dtbcount=""
+		rm -f fit-image.its
+
+		fitimage_emit_fit_header
+
+		#
+		# Step 1: Prepare a kernel image section.
+		#
+		fitimage_emit_section_maint imagestart
+
+		uboot_prep_kimage
+		fitimage_emit_section_kernel "${kernelcount}" linux.bin "${linux_comp}"
+
+		#
+		# Step 2: Prepare a DTB image section
+		#
+		if test -n "${KERNEL_DEVICETREE}"; then
+			dtbcount=1
+			for DTB in ${KERNEL_DEVICETREE}; do
+				if echo ${DTB} | grep -q '/dts/'; then
+					bbwarn "${DTB} contains the full path to the the dts file, but only the dtb name should be used."
+					DTB=`basename ${DTB} | sed 's,\.dts$,.dtb,g'`
+				fi
+				DTB_PATH="arch/${ARCH}/boot/dts/${DTB}"
+				if [ ! -e "${DTB_PATH}" ]; then
+					DTB_PATH="arch/${ARCH}/boot/${DTB}"
+				fi
+
+				fitimage_emit_section_dtb ${dtbcount} ${DTB_PATH}
+				dtbcount=`expr ${dtbcount} + 1`
+			done
+		fi
+
+		fitimage_emit_section_maint sectend
+
+		# Force the first Kernel and DTB in the default config
+		kernelcount=1
+		dtbcount=1
+
+		#
+		# Step 3: Prepare a configurations section
+		#
+		fitimage_emit_section_maint confstart
+
+		fitimage_emit_section_config ${kernelcount} ${dtbcount}
+
+		fitimage_emit_section_maint sectend
+
+		fitimage_emit_section_maint fitend
+
+		#
+		# Step 4: Assemble the image
+		#
+		uboot-mkimage -f fit-image.its arch/${ARCH}/boot/fitImage
+	fi
+}
+
+addtask assemble_fitimage before do_install after do_compile
+
+kernel_do_deploy_append() {
+	# Update deploy directory
+	if test "x${KERNEL_IMAGETYPE}" = "xfitImage" ; then
+		cd ${B}
+		echo "Copying fit-image.its source file..."
+		its_base_name="${KERNEL_IMAGETYPE}-its-${PV}-${PR}-${MACHINE}-${DATETIME}"
+		its_symlink_name=${KERNEL_IMAGETYPE}-its-${MACHINE}
+		install -m 0644 fit-image.its ${DEPLOYDIR}/${its_base_name}.its
+		linux_bin_base_name="${KERNEL_IMAGETYPE}-linux.bin-${PV}-${PR}-${MACHINE}-${DATETIME}"
+		linux_bin_symlink_name=${KERNEL_IMAGETYPE}-linux.bin-${MACHINE}
+		install -m 0644 linux.bin ${DEPLOYDIR}/${linux_bin_base_name}.bin
+
+		cd ${DEPLOYDIR}
+		ln -sf ${its_base_name}.its ${its_symlink_name}.its
+		ln -sf ${linux_bin_base_name}.bin ${linux_bin_symlink_name}.bin
+	fi
+}