bmaptool allows to drastically reduce the amount of data to transfer
when writing to an SD card. Example with a 544 MiB sdcard.img:
$ bmaptool create sdcard.img > sdcard.bmap
$ gzip sdcard.img
$ bmaptool copy sdcard.img.gz /dev/sdc
bmaptool: info: discovered bmap file 'sdcard.bmap'
bmaptool: info: block map format version 2.0
bmaptool: info: 139265 blocks of size 4096 (544.0 MiB), mapped 23918 blocks (93.4 MiB or 17.2%)
bmaptool: info: copying image 'sdcard.img.gz' to block device '/dev/sdc' using bmap file 'sdcard.bmap'
bmaptool: info: 100% copied
bmaptool: info: synchronizing '/dev/sdc'
bmaptool: info: copying time: 7.7s, copying speed 12.1 MiB/sec
So it means that instead of writing 544 MiB, only 93.4 MiB had to be
written.
In terms of implementation details, compared to the target bmap-tools
package, there are fewer "selects" that are needed because:
- The dependency on setuptools is not needed, because the package
uses the setuptools SETUP_TYPE, so host-python-setuptools is
already a build dependency.
- host-python and host-python3 are always built with Expat XML
support.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Nicolas Carrier <nicolas.carrier@orolia.com>
[Thomas: numerous reworks, add myself in DEVELOPERS]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
