Per region file arguments: Difference between revisions
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[-i <region>[:<file>]]... -r|-w|-v [<filename>] | [-i <region>[:<file>]]... -r|-w|-v [<filename>] | ||
Where '''<filename>''' can be given anywhere on the command line ( | Where '''<filename>''' can be given anywhere on the command line (non-positional, matching legacy flashrom behavior) | ||
==== Rules: ==== | ==== Rules: ==== |
Revision as of 06:11, 27 November 2018
Current chromium impl.
Current chromium flashrom implements the syntax like this:
[-i <region>[:<file>]]... -r|-w|-v [<filename>]
Where <filename> can be given anywhere on the command line (non-positional, matching legacy flashrom behavior)
Rules:
- Argument to -r/-w/-v is optional.
- If used, it tells flashrom to operate on a ROM-sized file.
- If not, flashrom will only operate on region-sized files.
- If no argument to -r/-w/-v is specified, then files must be specified via -i arguments.
- -r/-w/-v and -i options are non-positional, allowing commands to be easily constructed dynamically by higher-level logic.
- For reading:
- If -i region:<file> is used, read content from region into <file>.
- If any -i region:<file> is specified along with -r <filename>, read all included regions into <filename> and all included regions with a <file> specified into the respective file
- For writing and verifying:
- If -i region:<file> is used, write content from <file> to region or verify content from <file> against region.
- If any -i region:<file> is specified along with -w <filename>, the data of -i region:<file> will overwrite data in <filename>. This is useful for patching specific regions of a generic image, for example if you have a release image for a platform and wish to patch it with machine-specific data (such as MAC address) at manufacturing time.
- Regions with files specified via -i region:<file> must not overlap
More examples: https://www.chromium.org/chromium-os/packages/cros-flashrom#TOC-Partial-Reads-and-Writes
More explicit alternative
[-i <region>]... (-r|-w|-v [<region>:]<filename>)...
Easier to implement, no optional arguments, no non-positional arguments.
Rules for sanity:
- combinations of -r/-w/-v are not allowed
- -r/-w/-v <filename> (i.e. without a <region>) may only be specified once
- if no -r/-w/-v <filename> (i.e. without a <region>) is specified, no -i arguments may be given either
optionally, stricter
Never mix <region>:<file> with the old -i syntax in one invocation:
([-i <region>]... (-r|-w|-v <filename>) | (-r|-w|-v <region>:<filename>)...)
Files not matching the region's size
Both syntaxes can be extended for files that are smaller than the region:
<region>[<filename>
would denote that the file's contents should be placed at the start/bottom of the region,
<region>]<filename>
that the file's contents should be placed at the end/top of the region. By default the uncovered part of the region should be kept as is, unless
--pad
is specified, in which case the uncovered part would be padded with the flash chip's erased state (usually 0xff).
Additonal rules
- Beside `:`, `[` and `]` wouldn't be allowed in region names.