tree b0222eaf1d728eda3c988f504f6dd1d0fb5b3694
parent 7f0c3ec56b794313b8d23346f8b75bee711c739d
author Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net> 1268008952 +0000
committer Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net> 1268008952 +0000

Write granularity is chip specific

The following write granularities exist according to my datasheet
survey: - 1 bit. Each bit can be cleared individually. - 1 byte. A byte
can be written once. Further writes to an already written byte cause
the contents to be either undefined or to stay unchanged. - 128 bytes.
If less than 128 bytes are written, the rest will be erased. Each write
to a 128-byte region will trigger an automatic erase before anything is
written. Very uncommon behaviour. - 256 bytes. If less than 256 bytes
are written, the contents of the unwritten bytes are undefined.

Note that chips with default 256-byte writes, which keep the original
contents for unwritten bytes, have a granularity of 1 byte.

Handle 1-bit, 1-byte and 256-byte write granularity.

Corresponding to flashrom svn r927.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Sean Nelson <audiohacked@gmail.com>
Acked-by: David Hendricks <dhendrix@google.com>