[flashrom] flashrom as programmer slow because it reads the whole SPI Flash contents before writing anything

[R. Diez]

Hi all:

I am trying to use flashrom with a fast generic FTDI FT2232H adapter as 
an SPI Flash programmer in a small production line.

The SPI Flash chip can hold 8 MiB of data, but we are only using the 
first 512 KiB of it.

I found flashrom to be surprisingly slow. I started digging and the step 
"Reading old flash chip contents..." is taking minutes. It looks like 
flashrom is reading the whole contents before writing anything at all.

I am using 7.5 MHz at the moment. I cannot pump up the frequency too 
much, as I am still using flywires to connect the SPI flash chip to the 
programmer.

I know that the flash chips are empty (0xFF), so flashrom does not need 
to read anything beforehand. If it is going to read anything, the first 
512 KiB would suffice, because I am not touching anything else.

I found the following in the source code:

   int read_all_first = 1; /* FIXME: Make this configurable. */

I also found the following message about it:

   http://www.flashrom.org/pipermail/flashrom/2011-December/008440.html

I guess the corresponding command-line argument is still missing.

I cannot tell how hard it would be to code and test the missing parts. 
The "Development Guidelines" are several pages long. There are very many 
unmerged patches in the pipeline, and some of them are years old. The 
repository is in Subversion. In summary, not very encouraging.

Does anybody know of some fork or alternative that does not read 
everything before writing any data at all?

Please copy me on any answers because I am not subscribed to the mailing 
list.

Regards,
   rdiez