[flashrom] [PATCH] Add Altera USB-Blaster SPI programmer.

[Kyösti Mälkki]

On Mon, 2012-10-29 at 01:33 +0100, Stefan Tauner wrote: 
> Adds support for the Altera USB-Blaster programming dongle in
> Active Serial (AS) mode.
> Tested on both original product and a clone dongle.
> 
> Signed-off-by: James Laird <jhl at mafipulation.org>
> Signed-off-by: Kyösti Mälkki <kyosti.malkki at gmail.com>
> Signed-off-by: Stefan Tauner <stefan.tauner at student.tuwien.ac.at>
> ---
> 
> Rebased on Kyösti's version.
> Fixed Makefile and whitespace, cleaned up a few things,
> added a manpage... please retest on hardware.
> 
> Can someone please explain to me why send_read() does what it does?
> 

Thanks, your clean-up looks good.

Tested on both a clone with C8051F321 and the original product.

The blaster design is described here:
http://sourceforge.net/apps/mediawiki/urjtag/index.php?title=Cable_Altera_USB-Blaster

As for send_read(), to read a byte from SPI, one must first write a byte
to the USB. Stupid, but that is the design. This hardware has
particularly bad performance penalty when reading in small chunks of
pagesize or 256 bytes.

With non-blocking bulk submits in libusb-1.0, the raw read speed can be
increased by factor of 2 for clone and by 5 for original product.

Regards,
KM