[PATCH v2 3/4] meta/classes: added ubi-img class

[claudius.heine.ext@siemens.com]

From: Claudius Heine <ch@denx.de>

This class implements a new image type for UBI formatted nand flashes.

It allows custom ubinize configuration file templates to be placed into
the SRC_URI of the image recipe and has mechanims to replace variables
within those. It does this by using `envsubst` from the gettext project.

The interface for custom template variables is implemented via the
`UBINIZE_CFG_TMPL_VARS` bitbake variable. The value of this variable is
an array of template variable names. Each template variable name
corresponds to a flag of the `UBINIZE_CFG_TMPL_VARS` variable, with
which the value can be set.

Signed-off-by: Claudius Heine <ch@denx.de>
---
 doc/user_manual.md           |  2 +
 meta/classes/ubi-img.bbclass | 73 ++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+)
 create mode 100644 meta/classes/ubi-img.bbclass

diff --git a/doc/user_manual.md b/doc/user_manual.md
index c9924ad..c9e18e0 100644
--- a/doc/user_manual.md
+++ b/doc/user_manual.md
@@ -350,6 +350,7 @@ Isar can generate various images types for specific machine. The type of the ima
  - `ext4` - Raw ext4 filesystem image (default option for `qemuarm` machine).
  - `rpi-sdimg` - A complete, partitioned Raspberry Pi SD card image (default option for the `rpi` machine).
  - `wic-img` - A full disk image with user-specified partitions created and populated using the wic tool.
+ - `ubi-img` - A image for use on mtd nand partitions employing UBI
 
 ---
 
@@ -477,6 +478,7 @@ Isar contains additional image type classes that can be used as reference:
  - `rpi-sdimg`
  - `targz-img`
  - `ubifs-img`
+ - `ubi-img`
  - `wic-img`
 
 ---
diff --git a/meta/classes/ubi-img.bbclass b/meta/classes/ubi-img.bbclass
new file mode 100644
index 0000000..078293e
--- /dev/null
+++ b/meta/classes/ubi-img.bbclass
@@ -0,0 +1,73 @@
+# This software is a part of ISAR.
+# Copyright (C) Siemens AG, 2019
+#
+# SPDX-License-Identifier: MIT
+
+python() {
+    if not d.getVar("UBINIZE_ARGS"):
+        bb.fatal("UBINIZE_ARGS must be set")
+}
+
+UBINIZE_CFG_TMPL ??= "ubinize.cfg.tmpl"
+UBINIZE_CFG_TMPL_VARS ??= ""
+UBINIZE_CFG ??= "ubinize.cfg"
+
+inherit image
+
+UBI_IMAGE_FILE ?= "${IMAGE_FULLNAME}.ubi.img"
+
+IMAGER_INSTALL += "mtd-utils"
+
+PP = "/home/builder/${PN}"
+PP_DEPLOY = "${PP}/deploy"
+PP_ROOTFS = "${PP}/rootfs"
+PP_WORK = "${PP}/work"
+
+BUILDROOT = "${BUILDCHROOT_DIR}${PP}"
+BUILDROOT_DEPLOY = "${BUILDCHROOT_DIR}${PP_DEPLOY}"
+BUILDROOT_ROOTFS = "${BUILDCHROOT_DIR}${PP_ROOTFS}"
+BUILDROOT_WORK = "${BUILDCHROOT_DIR}${PP_WORK}"
+
+do_ubi_image[stamp-extra-info] = "${DISTRO}-${MACHINE}"
+
+def get_ubi_exports(d):
+    template_vars = (d.getVar("UBINIZE_CFG_TMPL_VARS", True) or "").split()
+    template_vars_flags = (d.getVarFlags("UBINIZE_CFG_TMPL_VARS") or {})
+    return " ".join("{}=\"{}\"".format(name, template_vars_flags[name])
+                    for name in template_vars)
+
+def get_envsubst_args(d):
+    template_vars = (d.getVar("UBINIZE_CFG_TMPL_VARS", True) or "").split()
+    return " ".join("\\${{{}}}".format(name)
+                    for name in template_vars)
+
+# Generate ubi filesystem image
+do_ubi_image() {
+    if [ ! -e "${WORKDIR}/${UBINIZE_CFG_TMPL}" -a \
+         ! -e "${WORKDIR}/${UBINIZE_CFG}" ]; then
+        die "Neigher UBINIZE_CFG_TMPL nor UBINIZE_CFG contain existing" \
+            "ubinize configuration file"
+    fi
+
+    rm -f ${DEPLOY_DIR_IMAGE}/${UBI_IMAGE_FILE}
+
+    buildchroot_do_mounts
+
+    sudo flock ${MOUNT_LOCKFILE} -c ' \
+        mkdir -p ${BUILDROOT_DEPLOY} ${BUILDROOT_ROOTFS} ${BUILDROOT_WORK}
+        mount --bind ${DEPLOY_DIR_IMAGE} ${BUILDROOT_DEPLOY}
+        mount --bind ${IMAGE_ROOTFS} ${BUILDROOT_ROOTFS}
+        mount --bind ${WORKDIR} ${BUILDROOT_WORK}
+    '
+
+    if [ -e "${WORKDIR}/${UBINIZE_CFG_TMPL}" ]; then
+        export ${@get_ubi_exports(d)}
+        envsubst "${@get_envsubst_args(d)}" \
+            < ${WORKDIR}/${UBINIZE_CFG_TMPL} > ${WORKDIR}/${UBINIZE_CFG} 
+    fi
+
+    # Create ubi image using buildchroot tools
+    sudo chroot ${BUILDCHROOT_DIR} /usr/sbin/ubinize ${UBINIZE_ARGS} \
+                -o "${PP_DEPLOY}/${UBI_IMAGE_FILE}" "${PP_WORK}/${UBINIZE_CFG}"
+}
+addtask ubi_image before do_build after do_copy_boot_files do_install_imager_deps do_unpack
-- 
2.20.1