classes/image_types: Add vfat image type

Adds support for creating FAT formatted file system images (useful for
boot partitions on some SoCs).

Note that FAT partitions are limited in what they can represent (no
symlinks or device files), so they can't really be used for general
purpose root file systems. As such, they are skipped when testing for
that purpose.

(From OE-Core rev: 440fa508d362b8a449beb1b82dd999e980b753b7)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 16 insertions, 1 deletions

diff --git a/meta/classes-recipe/image_types.bbclass b/meta/classes-recipe/image_types.bbclass
index fdee835e7c..4aed64e27f 100644
--- a/meta/classes-recipe/image_types.bbclass
+++ b/meta/classes-recipe/image_types.bbclass
@@ -131,6 +131,15 @@ IMAGE_CMD:erofs = "mkfs.erofs ${EXTRA_IMAGECMD} ${IMGDEPLOYDIR}/${IMAGE_NAME}.er
 IMAGE_CMD:erofs-lz4 = "mkfs.erofs -zlz4 ${EXTRA_IMAGECMD} ${IMGDEPLOYDIR}/${IMAGE_NAME}.erofs-lz4 ${IMAGE_ROOTFS}"
 IMAGE_CMD:erofs-lz4hc = "mkfs.erofs -zlz4hc ${EXTRA_IMAGECMD} ${IMGDEPLOYDIR}/${IMAGE_NAME}.erofs-lz4hc ${IMAGE_ROOTFS}"
 
+# Note that vfat can't handle all types of files that a real linux file system
+# can (e.g. device files, symlinks, etc.) and therefore it not suitable for all
+# use cases
+oe_mkvfatfs () {
+    mkfs.vfat $@ -C ${IMGDEPLOYDIR}/${IMAGE_NAME}${IMAGE_NAME_SUFFIX}.vfat ${ROOTFS_SIZE}
+    mcopy -i "${IMGDEPLOYDIR}/${IMAGE_NAME}${IMAGE_NAME_SUFFIX}.vfat" -vsmpQ ${IMAGE_ROOTFS}/* ::/
+}
+
+IMAGE_CMD:vfat = "oe_mkvfatfs ${EXTRA_IMAGECMD}"
 
 IMAGE_CMD_TAR ?= "tar"
 # ignore return code 1 "file changed as we read it" as other tasks(e.g. do_image_wic) may be hardlinking rootfs
@@ -266,6 +275,10 @@ EXTRA_IMAGECMD:ext4 ?= "-i 4096"
 EXTRA_IMAGECMD:btrfs ?= "-n 4096 --shrink"
 EXTRA_IMAGECMD:f2fs ?= ""
 
+# If a specific FAT size is needed, set it here (e.g. "-F 32"/"-F 16"/"-F 12")
+# otherwise mkfs.vfat will automatically pick one.
+EXTRA_IMAGECMD:vfat ?= ""
+
 do_image_cpio[depends] += "cpio-native:do_populate_sysroot"
 do_image_jffs2[depends] += "mtd-utils-native:do_populate_sysroot"
 do_image_cramfs[depends] += "util-linux-native:do_populate_sysroot"
@@ -285,6 +298,7 @@ do_image_f2fs[depends] += "f2fs-tools-native:do_populate_sysroot"
 do_image_erofs[depends] += "erofs-utils-native:do_populate_sysroot"
 do_image_erofs_lz4[depends] += "erofs-utils-native:do_populate_sysroot"
 do_image_erofs_lz4hc[depends] += "erofs-utils-native:do_populate_sysroot"
+do_image_vfat[depends] += "dosfstools-native:do_populate_sysroot mtools-native:do_populate_sysroot"
 
 # This variable is available to request which values are suitable for IMAGE_FSTYPES
 IMAGE_TYPES = " \
@@ -294,6 +308,7 @@ IMAGE_TYPES = " \
     ext3 ext3.gz \
     ext4 ext4.gz \
     btrfs \
+    vfat \
     squashfs squashfs-xz squashfs-lzo squashfs-lz4 squashfs-zst \
     ubi ubifs multiubi \
     tar tar.gz tar.bz2 tar.xz tar.lz4 tar.zst \
diff --git a/meta/lib/oeqa/selftest/cases/imagefeatures.py b/meta/lib/oeqa/selftest/cases/imagefeatures.py
index a5e069d0be..dc88c222bd 100644
--- a/meta/lib/oeqa/selftest/cases/imagefeatures.py
+++ b/meta/lib/oeqa/selftest/cases/imagefeatures.py
@@ -199,7 +199,7 @@ class ImageFeatures(OESelftestTestCase):
         image = 'core-image-minimal'
 
         all_image_types = set(get_bb_var("IMAGE_TYPES", image).split())
-        skip_image_types = set(('container', 'elf', 'f2fs', 'tar.zst', 'wic.zst', 'squashfs-lzo'))
+        skip_image_types = set(('container', 'elf', 'f2fs', 'tar.zst', 'wic.zst', 'squashfs-lzo', 'vfat'))
         img_types = all_image_types - skip_image_types
 
         config = """