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QONG FPGA Update using UrJtag

Abstract

This application note describes how to upgrade the FPGA with a new logic on the Freescale i.MX31 based module QONG module developed by Dave Srl. The upgrade is performed using the open source UrJTAG Universal JTAG tools.

Author

This document was written by Stefano Babic (sbabic {at} denx {dot} de).

Introduction

To offer maximum flexibility in each design, the QONG module combines the i.MX31 with a powerful FPGA, which allows adaptable I/O expansion as well as adding IP-cores for additional customized interfaces. To make use of this flexibility, it is necessary to install new versions of the FPGA code by downloading a bitstream. Also, sometimes updated versions of the FPGA code become available fixing problems and/or adding new features.

Please note that the actual bitstream contains some core functionalities that must be maintained. The bitstream delivered by Dave srl already contains an Ethernet controller that is used as main controller in U-Boot and Linux. The FPGA also contains a level shifter for the NAND flash. If a redesigned FPGA does not provide these core features neither Ethernet nor NAND flash will work.

On the QONG module, the required JTAG pins of the FPGA are connected to GPIO ports, so updates of the FPGA code can be done in software, without using external tools like a dedicated JTAG programmer.

Instead of writing custom software for this purpose, we decided to use the standard UrJTAG Universal JTAG tool.

Hardware configuration

It can be quite confusing to understand which FPGA can be updated as the evaluation boards contain an additional FPGA. This guide refers only to the FPGA present on the QONG module and does not apply to the Qong-EvbLite board, where the QONG module is integrated in the board itself and the FPGA is of a different type. For the same reason, if you have a Qong-EVB this guide refers only to the FPGA on the module, not on the motherboard. The QONG Module has an LFXP2 5E_FTBGA256 on board, while the boards are populated with an LFXP217E 256 FPBGA. Do not try to download a bitstream to an FPGA of different type, or you can damage your board. I am serious, this is not a joke. More information about the different FPGAs mounted on the QONG products can be found on the manufacturers site (Lattice).

WARNING and LEGAL DISCLAIMER

ALERT! Updating the FPGA code is a very critical operation. First of all, any attempts to meddle with the FPGA code will void any warranty you have. And if anything goes wrong your board will be broken, and you will not be able to fix it.

There is absolutely, positively NO WARRANTY, neither express or implied, offered with this documentation and software. You use this documentation and software at your own risk. In case of loss, no person or entity owes you anything whatsoever. You have been warned.

You have been warned!

How to generate the required SVF file

urjtag supports bitstreams in SVF format and if the file you generated is in another format, you must convert it before applying. The manufacturer offers a free tool for development and conversion between different formats (ispvmsystem).

Attached you will find the SVF file for the delivered bitstream. Please pay attention that the tool provided by lattice extends the SVF language using some non-standard commands, that are not interpreted by urjtag. This applies to the LOOP/ENDLOOP commands, which must be expanded into the complete list of statements.

Also attached is a simple script to convert the LOOP/ENDLOOP statements. The resulting file can be successfully interpreted by urjtag.

To get the SVF from your generated jedec file, start the ispvm tool (follow the instructions you find on the manufacturer site).

The tool should now generate a "quite" ready file for urjtag. If you open the file with an editor, you will find some comments that advise you about the incompatibility with the LOOP/ENDLOOP statements. You must also comment out the Frequency statement, as frequency will be set with urjtag. Now run the simple svf_to_urjtag.pl script attached to this page. This generates an SVF file compatible with urjtag.

For example, if qong-5C5-0.8.7.jed.svf is the output of the ispvsim tool, do the following:

./svf_to_urjtag.pl  < qong-5C5-0.8.7.jed.svf > qong-5C5-0.8.7.svf

Compiling and installing urjtag for QONG module

The gpio cable driver, required to drive some GPIOs as JTAG interface, is integrated in the actual urjtag tree. If you get urjtag via git, you do not need to apply the patch. you are now ready to install jtag on your system:

$ ./configure --disable-bus --without-libusb --host=arm-linux --target=arm-linux --enable-cable=gpio $ make $ make DESTDIR= install

--+++ Compiling and installing actual urjtag

Get sources via git from the UrJTAG home site.

--+++ Applying the patch to urjtag 0.10

On your host, download the urjtag tool and apply the patches in attachment:

$ wget http://surfnet.dl.sourceforge.net/sourceforge/urjtag/urjtag-0.10.tar.bz2
$ tar xjf urjtag-0.10.tar.bz2
$ cd urjtag-0.10
$ patch -p1 < 0001-Support-updating-FPGA-on-QONG-module.patch
$ patch -p1 < 0002-Add-definition-files-for-Lattice-XFP2-5e-256-FPGA.patch
$ autoreconf

Now you are ready to cross-compile the tool. Set up for using the ELDK toolchain as usual.

$ ./configure --disable-bus --without-libusb --host=arm-linux --target=arm-linux --enable-cable=qong_gpio
$ make 
$ make DESTDIR=<PATH_TO_INSTALL> install

You now have the urjtag tools in the subdirectory usr/local starting from the path you have chosen. You have to put this stuff on your rootfilesystem. Please be aware that:

Starting the UrjTag tool on the QONG module

on the target, you can start the jtag command:

-bash-3.2# ./jtag

UrJTAG 0.10 #1502
Copyright (C) 2002, 2003 ETC s.r.o.
Copyright (C) 2007, 2008, 2009 Kolja Waschk and the respective authors

UrJTAG is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
There is absolutely no warranty for UrJTAG.

Now you can enable the qong module:

For 0.10 Version:

jtag> cable qong_gpio
Initializing QONG GPIO JTAG Chain
qong_init:
jtag> detect
IR length: 8
Chain length: 1
Device Id: 00000001001010011001000001000011 (0x0000000001299043)
  Manufacturer: Lattice Semiconductors
  Part(0):         LFXP2-5E-FTBGA256
  Stepping:     0
  Filename:     /usr/local/share/urjtag/lattice/lfxp2-5e_ftbga256/lfxp2_5e_ftbga256

If you use the actual urjtag sources

jtag> cable gpio tdo=7 tdi=8 tck=26 tms=25
Initializing GPIO JTAG Chain
gpio_init:
jtag> detect
IR length: 8
Chain length: 1
Device Id: 00000001001010011001000001000011 (0x0000000001299043)
  Manufacturer: Lattice Semiconductors
  Part(0):         LFXP2-5E-FTBGA256
  Stepping:     0
  Filename:     /usr/local/share/urjtag/lattice/lfxp2-5e_ftbga256/lfxp2_5e_ftbga256

As you see, the driver in the actual tree has no reference anymore to the QONG module and can be used on any system with available GPIOs to drive the JTAG interface and you are able to configure the meaning of the gpios at runtime.

If detect does not work, do not try with the following commands. With detect, you can check if the jtag connection to the FPGA is working. The tool must report the FPGA ID as described here.

Setting the frequency

Now set the frequency. As you can see, I sets the frequency more than one time. It seems that computed frequency is always smaller the first time is set. Normally, there is no reason to set it multiple times and the following log will only show that the frequency remains constant after it is set for the second time.

jtag> frequency
Current TCK frequency is 0 Hz
jtag> frequency 1000000
Setting TCK frequency to 1000000 Hz
requested frequency 1000000, now calibrating delay loop
new real frequency 53508, delay 0
operating without delay
done
jtag> frequency 1000000
Setting TCK frequency to 1000000 Hz
requested frequency 1000000, now calibrating delay loop
new real frequency 60695.9, delay 0
operating without delay
done
jtag> frequency 1000000
Setting TCK frequency to 1000000 Hz
requested frequency 1000000, now calibrating delay loop
new real frequency 60696.3, delay 0
operating without delay
done
jtag> print
 No. Manufacturer              Part                 Stepping Instruction          Register
------------------------------------------------------------------------------------------------------------------
   0 Lattice Semiconductors    LFXP2-5E-FTBGA256    0        BYPASS               BYPASS

Dowloading the FPGA bitstream

You can now start the update with the svf command:

jtag> svf <your_svf_file> progress

At the beginning there are some expected errors, do not care about them. The real update starts when the progress is shown as percentage. No error is expected after that.

If everything is fine, you will get the message

Scanned device output matched expected TDO values.

Now power cycle the system and check if the update was okay as currently only the flash on the FPGA was updated, but not the SRAM containing the logic.

If everything is ok, you will see U-Boot running reporting the new FPGA version:

U-Boot 2010.03-00172-g133734b-dirty (Apr 28 2010 - 13:49:18)

CPU:   Freescale i.MX31 at 398 MHz
Board: DAVE/DENX Qong
DRAM:  128 MB
Flash: 32 MB
NAND:  128 MiB
In:    serial
Out:   serial
Err:   serial
FPGA:  version register = 0.8.7
Net:   dnet0
Hit any key to stop autoboot:  0 

If the version reported is 15.15.255, your FPGA is still unprogrammed. This means that u-boot reads only 0xFF when tries to access to the version register (or to any other register in FPGA). In this situation, network and NAND are not working. Try to repeat the procedure to restore the FPGA.


Attachment sort Action Size Date Who Comment
0001-Support-updating-FPGA-on-QONG-module.patch manage 11.9 K 29 Apr 2010 - 10:27 StefanoBabic Cable driver for QONG module
0002-Add-definition-files-for-Lattice-XFP2-5e-256-FPGA.patch manage 56.0 K 29 Apr 2010 - 10:27 StefanoBabic Description file for the Lattice FPGA
svf_to_urjtag.pl.txt manage 0.3 K 29 Apr 2010 - 11:03 StefanoBabic Script to remove incompatibilities in generated SVF file
QONG-5C5-0.8.7_woloop.SVF manage 2714.4 K 29 Apr 2010 - 11:05 StefanoBabic