build/images/fvm.gni

# Copyright 2018 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import("//build/compiled_action.gni")

declare_args() {
  # The size in bytes of the FVM partition on the target eMMC devices.
  # Specifying this parameter will lead build to generate a fvm.fastboot.blk
  # suitable for flashing through fastboot for eMMC devices.
  fvm_emmc_partition_size = false

  # The max size of the disk where the FVM is written. This is used for
  # preallocating metadata to determine how much the FVM can expand on disk.
  # Only applies to sparse FVM images. At sparse image construction time, the
  # build fails if the inputs are larger than `fvm_max_disk_size`. At paving
  # time, the FVM will be sized to the target's disk size up to
  # `fvm_max_disk_size`. If the size of the disk increases after initial paving,
  # the FVM will resize up to `fvm_max_disk_size`. During paving, if the target
  # FVM has declared a smaller size than `fvm_max_disk_size`, the FVM is
  # reinitialized to the larger size.
  # The default value is false which sets the max disk size to the size of the disk
  # at pave/format time.
  fvm_max_disk_size = false

  # The size of the FVM partition images "slice size". The FVM slice size is a
  # minimum size of a particular chunk of a partition that is stored within
  # FVM. A very small slice size may lead to decreased throughput. A very large
  # slice size may lead to wasted space. The selected default size of 8mb is
  # selected for conservation of space, rather than performance.
  fvm_slice_size = 8388608

  # Number of slices reserved by FVM for internal usage. A reservation
  # partition will be added to the FVM image, containing this many slices.
  # If set to 0, then no reservation partition will be added.
  fvm_reserved_slices = 0

  # The following blobfs_* and minfs_* arguments are used to determine the
  # initial dimensions of the blobfs and minfs partitions added to an FVM
  # image. If they are unset, the sizes of the input blobfs/minfs images will
  # determine the dimensions of the respective partition within FVM.
  #
  # These dimensions cannot make a partition smaller than the image provided
  # to the FVM tool; in that case, the partition dimensions would be expanded
  # to fit the input image.
  #
  # There are both board-level overrides and product-level dimensions. The
  # product-level overrides, if set, will take precedence.

  # minimum_inodes is the number of inodes to reserve for the fs
  # A value of false does not reserve any additional space than minimum
  # required for the filesystem.
  blobfs_board_minimum_inodes = false
  blobfs_product_minimum_inodes = false

  # Number of bytes to reserve for data in the fs. This is in addition
  # to what is reserved, if any, for the inodes. Data bytes constitutes
  # "usable" space of the fs.
  # A value of false does not reserve any additional space than minimum
  # required for the filesystem.
  blobfs_board_minimum_data_bytes = false
  blobfs_product_minimum_data_bytes = false
  minfs_board_minimum_data_bytes = false
  minfs_product_minimum_data_bytes = false

  # In addition to reserving space for inodes and data, fs needs additional
  # space for maintaining some internal data structures. So the
  # space required to reserve inodes and data may exceed sum of the space
  # needed for inodes and data.
  # maximum_bytes puts an upper bound on the total bytes reserved for inodes,
  # data bytes and reservation for all other internal fs metadata.
  # A value of false does not put any upper bound. A filesystem may
  # reserve few blocks required for its operations.
  blobfs_board_maximum_bytes = false
  blobfs_product_maximum_bytes = false
  minfs_board_maximum_bytes = false
  minfs_product_maximum_bytes = false

  # End of variables for blobfs/minfs dimensions

  # Specifying these variables will generate a NAND FVM image suitable for
  # directly flashing via fastboot. The NAND characteristics are required
  # in order to properly initialize the FTL metadata in the OOB area.
  # `fvm_max_disk_size` should also be nonzero or else minfs will not have any
  # room to initialize on boot.
  fvm_ftl_nand_page_size = false
  fvm_ftl_nand_oob_size = false
  fvm_ftl_nand_pages_per_block = false
  fvm_ftl_nand_block_count = false

  # How to compress the FVM image used for fastboot flashing.
  # Possible values:
  #   * "none": no compression
  #   * "default": no compression on NAND, lz4 compression on eMMC.
  #   * any other value is passed as the FVM "--compress" arg
  fvm_fastboot_compression = "default"
}