nerves_system_br

# Firmware configuration file for the Beaglebone Black

define(FINALIZE_FW, "/tmp/finalize.fw")

# Default paths if not specified via the commandline
define(ROOTFS, "${NERVES_SYSTEM}/images/rootfs.squashfs")

# This configuration file will create an image that
# has an MBR and the following 3 partitions:
#
# +----------------------------+
# | MBR                        |
# +----------------------------+
# | Boot partition (FAT32)     |
# | u-boot.img                 |
# | uenv.txt                   |
# | zImage                     |
# +----------------------------+
# | p1*: Rootfs A (squashfs)   |
# +----------------------------+
# | p1*: Rootfs B (squashfs)   |
# +----------------------------+
# | p2: Application (FAT32)    |
# +----------------------------+
#
# The p1 partition points to whichever of Rootfs A or B that
# is active.

# The boot partition contains MLO, u-boot.img, zImage, and has
# room for a debug uEnv.txt if desired
define(BOOT_PART_OFFSET, 63)
define(BOOT_PART_COUNT, 16321)

# Let the rootfs have room to grow up to 128 MiB and align
# it to the nearest 1 MB boundary
define(ROOTFS_A_PART_OFFSET, 16384)
define(ROOTFS_A_PART_COUNT, 289044)
define(ROOTFS_B_PART_OFFSET, 305428)
define(ROOTFS_B_PART_COUNT, 289044)

# Application partition
# NOTE: Keep the total amount used under 1.78 GiB so that
#       everything fits in the "2 GB" eMMC.
define(APP_PART_OFFSET, 594472)
define(APP_PART_COUNT, 1048576)

# Firmware metadata
meta-product = "Nerves Firmware"
meta-description = ""
meta-version = ${NERVES_SDK_VERSION}
meta-platform = "bbb"
meta-architecture = "arm"
meta-author = "Frank Hunleth"

# File resources are listed in the order that they are included in the .fw file
# This is important, since this is the order that they're written on a firmware
# update due to the event driven nature of the update system.
file-resource MLO {
    host-path = "${NERVES_SYSTEM}/images/MLO"
}
file-resource u-boot.img {
    host-path = "${NERVES_SYSTEM}/images/u-boot.img"
}
file-resource boot.scr {
    host-path = "${NERVES_SYSTEM}/images/boot.scr"
}
file-resource zImage {
    host-path = "${NERVES_SYSTEM}/images/zImage"
}
file-resource am335x-boneblack.dtb {
    host-path = "${NERVES_SYSTEM}/images/am335x-boneblack.dtb"
}
file-resource rootfs.img {
    host-path = ${ROOTFS}
}

mbr mbr-a {
    partition 0 {
        block-offset = ${BOOT_PART_OFFSET}
        block-count = ${BOOT_PART_COUNT}
        type = 0xc # FAT32
        boot = true
    }
    partition 1 {
        block-offset = ${ROOTFS_A_PART_OFFSET}
        block-count = ${ROOTFS_A_PART_COUNT}
        type = 0x83 # Linux
    }
    partition 2 {
        block-offset = ${APP_PART_OFFSET}
        block-count = ${APP_PART_COUNT}
        type = 0xc # FAT32
    }
    # partition 3 is unused
}

mbr mbr-b {
    partition 0 {
        block-offset = ${BOOT_PART_OFFSET}
        block-count = ${BOOT_PART_COUNT}
        type = 0xc # FAT32
        boot = true
    }
    partition 1 {
        block-offset = ${ROOTFS_B_PART_OFFSET}
        block-count = ${ROOTFS_B_PART_COUNT}
        type = 0x83 # Linux
    }
    partition 2 {
        block-offset = ${APP_PART_OFFSET}
        block-count = ${APP_PART_COUNT}
        type = 0xc # FAT32
    }
    # partition 3 is unused
}

# This firmware task writes everything to the destination media
task complete {
    # Only match if not mounted
    require-unmounted-destination = true

    # Everything that gets written can be verified on the fly.
    # This speeds things up, since we don't care about detecting
    # errors before data gets written.
    verify-on-the-fly = true

    on-init {
        mbr_write(mbr-a)

        fat_mkfs(${BOOT_PART_OFFSET}, ${BOOT_PART_COUNT})
        fat_setlabel(${BOOT_PART_OFFSET}, "BOOT")
    }

    on-resource MLO { fat_write(${BOOT_PART_OFFSET}, "MLO") }
    on-resource u-boot.img { fat_write(${BOOT_PART_OFFSET}, "u-boot.img") }
    on-resource boot.scr { fat_write(${BOOT_PART_OFFSET}, "boot.scr") }
    on-resource zImage { fat_write(${BOOT_PART_OFFSET}, "zImage") }
    on-resource am335x-boneblack.dtb { fat_write(${BOOT_PART_OFFSET}, "am335x-boneblack.dtb") }

    on-resource rootfs.img {
        # write to the first rootfs partition
        raw_write(${ROOTFS_A_PART_OFFSET})
    }

    on-finish {
        # Initialize the app partition last so that the boot
        # partition can be written in one go.
        fat_mkfs(${APP_PART_OFFSET}, ${APP_PART_COUNT})
        fat_setlabel(${APP_PART_OFFSET}, "APPDATA")
    }
}

task upgrade.a {
    # This task upgrades the A partition
    require-partition1-offset = ${ROOTFS_B_PART_OFFSET}

    # Since the upgrade won't run until it has been finalized, it's ok
    # to write data as it is read.
    verify-on-the-fly = true

    on-init {
        # Erase any old saved files from previous upgrades
        fat_rm(${BOOT_PART_OFFSET}, "zImage.pre")
        fat_rm(${BOOT_PART_OFFSET}, "am335x-boneblack.dtb.pre")
        fat_rm(${BOOT_PART_OFFSET}, "boot.scr.pre")
    }

    # Write the new firmware and Linux images, but don't
    # commit them. That way if the user aborts midway, we
    # still are using the original firmware.
    on-resource zImage { fat_write(${BOOT_PART_OFFSET}, "zImage.new") }
    on-resource boot.scr { fat_write(${BOOT_PART_OFFSET}, "boot.scr.new") }
    on-resource am335x-boneblack.dtb { fat_write(${BOOT_PART_OFFSET}, "am335x-boneblack.dtb.new") }

    on-resource rootfs.img {
        # write to the first rootfs partition
        raw_write(${ROOTFS_A_PART_OFFSET})
    }

    on-finish {
        # Until this .fw is run, the system will still boot to the old firmware
        fw_create(${FINALIZE_FW})
        # Add an empty file to flag mbr-a to be written
        fw_add_local_file(${FINALIZE_FW}, "write.mbr-a", "/dev/null")
    }

    on-error {
        # Clean up in case something goes wrong
        fat_rm(${BOOT_PART_OFFSET}, "zImage.new")
        fat_rm(${BOOT_PART_OFFSET}, "am335x-boneblack.dtb.new")
        fat_rm(${BOOT_PART_OFFSET}, "boot.scr.new")
    }
}

task upgrade.b {
    # This task upgrades the B partition
    require-partition1-offset = ${ROOTFS_A_PART_OFFSET}

    # Since the upgrade won't run until it has been finalized, it's ok
    # to write data as it is read.
    verify-on-the-fly = true

    on-init {
        fat_rm(${BOOT_PART_OFFSET}, "zImage.pre")
        fat_rm(${BOOT_PART_OFFSET}, "am335x-boneblack.dtb.pre")
        fat_rm(${BOOT_PART_OFFSET}, "boot.scr.pre")
    }

    on-resource zImage { fat_write(${BOOT_PART_OFFSET}, "zImage.new") }
    on-resource boot.scr { fat_write(${BOOT_PART_OFFSET}, "boot.scr.new") }
    on-resource am335x-boneblack.dtb { fat_write(${BOOT_PART_OFFSET}, "am335x-boneblack.dtb.new") }

    on-resource rootfs.img {
        # write to the first rootfs partition
        raw_write(${ROOTFS_B_PART_OFFSET})
    }

    on-finish {
        # Until this .fw is run, the system will still boot to the old firmware
        fw_create(${FINALIZE_FW})
        # Add an empty file to flag mbr-b to be written
        fw_add_local_file(${FINALIZE_FW}, "write.mbr-b", "/dev/null")
    }

    on-error {
        # Clean up in case something goes wrong
        fat_rm(${BOOT_PART_OFFSET}, "zImage.new")
        fat_rm(${BOOT_PART_OFFSET}, "am335x-boneblack.dtb.new")
        fat_rm(${BOOT_PART_OFFSET}, "boot.scr.new")
    }
}

# This action is intended to be called from ${FINALIZE_FW} after the "upgrade" task
# has been run. It requires the "write.mbr-a" or "write.mbr-b" resources to exist
# and those don't exist until the "upgrade" task makes them.
#
# The idea here is to be as atomic as possible for switching over from the old
# firmware release to the new one. As you can see, files need to be renamed,
# so it's not atomic. Ideally we'd just perform one write to switch the active
# root filesystem and be done, but the BBB requires more work due to the kernel,
# being stored in the first FAT file system. It is likely that this can be fixed.
task on-reboot {
    on-resource write.mbr-a {
        mbr_write(mbr-a)
    }
    on-resource write.mbr-b {
        mbr_write(mbr-b)
    }
    on-finish {
        fat_mv(${BOOT_PART_OFFSET}, "zImage", "zImage.pre")
        fat_mv(${BOOT_PART_OFFSET}, "boot.scr", "boot.scr.pre")
        fat_mv(${BOOT_PART_OFFSET}, "am335x-boneblack.dtb", "am335x-boneblack.dtb.pre")

        fat_mv(${BOOT_PART_OFFSET}, "zImage.new", "zImage")
        fat_mv(${BOOT_PART_OFFSET}, "boot.scr.new", "boot.scr")
        fat_mv(${BOOT_PART_OFFSET}, "am335x-boneblack.dtb.new", "am335x-boneblack.dtb")
    }
}