On Mon, 11 Jan 2016 14:58:12 +0100 "R. Diez" <rdiezmail-flashrom@yahoo.de> wrote:

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.

The reading serves a purpose (more than one actually)... one that does not give an advantage in your case though. flashrom can decide which blocks need to be rewritten and which can be left alone after reading the initial contents. This actually speeds up the process dramatically in many use cases. flashrom also reads the whole chip after writing to verify everything is fine which would slow you down even further. That's the way it is and it won't change anytime soon but we are aware of it. -- Kind regards/Mit freundlichen Grüßen, Stefan Tauner

Hi Ruben, On 11.01.2016 14:58, R. Diez wrote:

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.

If you can switch your production line to use flashrom on a Raspberry Pi or a Beaglebone Black for SPI programming with the SPI pins on those boards, reading a flash chip will only take seconds and writes will be really fast as well because the per-command latency is almost zero. With a SPI frequency of 8 MHz and a flash chip size of 8 MiB, reading the whole chip on a RPi or BBB takes roughly 9 seconds (to be precise, 8388608/256*(4+256)*8/8000000 seconds). For FT2232 based programmers, you get a lot of USB overhead (mostly latency) which makes reading slow, but writing is even worse. Regards, Carl-Daniel