Convert cypress firmware to be compiled by sdcc

[mithro]

Currently we use the closed source Kiel UV2 software for compiling the Cypress firmware.

We'd like to use open source tools instead, the sdcc compiler has support for the 8051 chip inside the chip and a number of people have already done a lot of the work. Take a look at the links below;

Links

• https://www.google.com.au/search?q=sdcc+cypress+ez+usb+firmware
• http://www.linux-usb.org/ezusb/
• http://braiden.org/?p=59
• https://github.com/hansiglaser/ezusb-firmware
• http://allmybrain.com/2009/04/14/fx2-cystream-throughput-test-with-sdcc-and-fx2lib/

[shenki]

I did a bit of reading. It looks like there are two options for developing an open source (no Cypress copyrights) SDCC built firmware:

• ezusb-firmware, a complete re-implementation of the headers and hardware support
• fx2lib, a LGPL library that is similar (at least in terms of filename?) to Cypress' code

allmybrain.com appears to be a good source of ideas for potential speedups when using fx2lib, should we require it down the track. They provide benchmarks of their implementation. I took at look at the source, and got it to build with a modern fx2lib and sdcc. The result is here https://github.com/shenki/cystream.git, if someone can test it using the included Python script that would be useful. (There appears to be a fx2 python module in fx2lib/examples that must be built in order to use this script).

At this stage, ezusb-firmware looks simpler, I suggest using this as a starting point for a re-implementation of the firmware.

[kripton]

The sigrok project also uses sdcc: http://sigrok.org/wiki/Fx2lafw code: http://sigrok.org/gitweb/?p=sigrok-firmware-fx2lafw.git;a=tree

[mithro]

Tim has started some of this work at https://github.com/mithro/HDMI2USB/tree/cypress-firmware

[mithro]

Example porting document can be found at http://www.danielclemente.com/placa_pi/index.en.html

[cfelton]

I haven't looked at the HDMI2USB FX2 firmware yet but I wrote and compiled previous FX2 code using SDCC for the USBP project and used it for a couple boards including this one. I am sure the firmware I used was the bare-minimal (I should go look at the source ...).

Are there are specific issues (road-blocks) you are currently dealing with?

[mithro]

@cfelton Lack of time is the major roadblock like always. I think I have a good handle on what needs to be done. The steps are,

• Add my newly ported .a52 descriptor information on an existing FOSS firmware (probably going to use the libFPGAlink firmware).
• Get the USB to FIFO bits working.
• Start adding new features!

New feature wise, I'd like the cypress to boot up and use JTAG to query the Spartan before enumeration. This is so it can include the serial number and use different usb ids if the FPGA had good firmware or not. Hence using a firmware which already does JTAG stuff makes sense.

[cfelton]

@mithro Yes, leveraging the existing JTAG is good! Isn't the JTAG in the FW very thin, it requires all the JTAG stream (commands) to be created by the host?

[mithro]

@cfelton Yes, you are correct - the JTAG implementations are extremely thin - basically just the bitbanging of the JTAG signals with correct transition timings. It should be pretty simple to make the firmware do the operations though because we only need some very specific operations rather than generic JTAG support.

The two possibility base firmware are;

• NeroJTAG @ https://github.com/makestuff/libfpgalink/tree/master/firmware/fx2
• fpga4u @ https://fpga4u.epfl.ch/wiki/FX2

[mithro]

Currently investigating using the libfpgalink FX2 firmware as base. Asked the original author for advice in https://github.com/makestuff/libfpgalink/issues/30

[mithro]

Fixed.

[mithro]

The HDMI2USB-jahanzeb-firmware is no longer under development.

All active development is now on the HDMI2USB-misoc-firmware which supports both the Atlys and Opsis boards and has loads of other new features!