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Contents

  1. D-Link DSL-G604T
  2. Device Hardware Features
  3. Linux
  4. Firmware ADAM2
  5. DSL-G604T hacking
  6. Creating a custom firmware
    1. Firmware overview
    2. Custom Firmware Distribution
    3. Toolchains
    4. Constructing the filesystem image
    5. Constructing the kernel image
  7. Serial Console
  8. AR7 Devices
    1. AR7 UART
    2. C62x DSP
    3. WiFi/VLYNQ
    4. Ethernet
  9. Other

D-Link DSL-G604T

http://www.dlink.ru/base/picz/dslg604t.jpg

Linuxdevices.com Device review

Device Hardware Features

http://www.sensi.org/~alec/images/DlinkDslG604t_PCB.jpg

Linux

D-Link DSL-G604T firmware is based on MontaVista Linux 2.4.17. 

Linux version 2.4.17_mvl21-malta-mips_fp_le (jordan@Jordan_Linux)
Compiled by gcc version 2.95.3 20010315 (release/MontaVista) 18 14:13:34 CST 2004

Serial Console BOOT log

CPU, Memory 

# cat cpuinfo
processor               : 0
cpu model               : MIPS 4KEc V4.8
BogoMIPS                : 149.91
wait instruction        : no
microsecond timers      : yes
extra interrupt vector  : yes
hardware watchpoint     : yes
VCED exceptions         : not available
VCEI exceptions         : not available

# cat meminfo
        total:    used:    free:  shared: buffers:  cached:
Mem:  14974976 13090816  1884160        0  1540096  4857856
Swap:        0        0        0
MemTotal:        14624 kB
MemFree:          1840 kB
MemShared:           0 kB
Buffers:          1504 kB
Cached:           4744 kB
SwapCached:          0 kB
Active:           3260 kB
Inactive:         4636 kB
HighTotal:           0 kB
HighFree:            0 kB
LowTotal:        14624 kB
LowFree:          1840 kB
SwapTotal:           0 kB
SwapFree:            0 kB

# cat mounts
/dev/mtdblock/0 / squashfs ro 0 0
none /dev devfs rw 0 0
proc /proc proc rw 0 0
ramfs /var ramfs rw 0 0

#df
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/mtdblock/0           1984      1984         0 100% /

Firmware ADAM2

D-Link DSL-G604T comes with ADAM2 firmware.

DSL-G604T hacking

Read this article:

http://dtors.ath.cx/index/actiontec

Creating a custom firmware

Firmware overview

D-Link DSL-G604T firmware is based on the MontaVista Linux 2.4.17.

It consists of:

Custom Firmware Distribution

There is success of AR7 port. SVN Kamikaze is work with 2.6.x kernel, Ethernet works, DSL works too, Wi-Fi is WIP. For more information see http://wiki.openwrt.org/OpenWrtDocs/Hardware/D-Link/DSL-G604T

Toolchains

http://www.linux-mips.org/wiki/index.php/Toolchains

http://www.uclibc.org/toolchains.html

Constructing the filesystem image

The filesystem image (mtd0) is a SquashFS compressed image containing all the binaries, www-interface, some Kernel modules etc. It has a maximum size of a 3392 (0x350000) kilobytes. Here's a layout of the most recent UK firmware's filesystem.

After modifying the filesystem layout you need to compress it back to squashfs image. The default kernel supports only version 1.x images. Using version 1.3r3 seems to work. 

$ mksquashfs imgdir fs-new.img -noappend
Creating little endian filesystem on fs-new.img, block size 32768.
...

After that you need to append a custom checksum to the image (at least while using the web interface for updating). This can be done with the supplied tool, TI-chksum-0.1. It's available in the D-Link's GPL tar ball. 

$ tichksum NDLinkUK_DSL-G604T_fs_V1.00B02T02.UK.20041126
File already contains the checksum, verifying
Calculated checksum is CFE70B86
Saved checksum is CFE70B86
Checksum validation successful!

$ tichksum fs-new.img
File doesn't contain the checksum, adding
Calculated checksum is 41ABB510
Added successfully

After that the filesystem image can be updated with the usual methods.

Constructing the kernel image

The Linux Kernel image is an "ADAM2 application" as required for ADAM2's "go" command. The file format is described above.

It contains a LZMA or zlib compressed linux 2.4.17 Montavista kernel an self-decompressor piggyback. The GPL source code seems to have a big patch against the default 2.4.17-montavista. Looks like it even has the needed configuration files. With default zlib compression the kernel image quite often can't fit to the 576 kilobytes, so it's necessary either to move more stuff to modules or disable some unnecessary stuff.

The "Vanilla" Linux Kernel does not provide compressed Kernel image for non-i386 architectures. See: Linux Kernel 2.4 Internals but our processor is MIPS.

The patched montavista-2.4.17 kernel tree has a make ram_zimage and make ram_zimage_pad targets. This targets generates kernel images in a SREC format (vmlinux.srec). The linux-2.4.17_mvl21/arch/mips/mips-boards/ti_avalanche/inflater/srec2bin.c utility is a tool to make an "ADAM2 application" from this MIPS SREC.

Note that adding the TI checksum adds another 8 bytes to it...

The D-Link "GPL-ed source" provides a zlib decompressor only. Take a "GPL source" from the NetgearDG834G support page. This device is based on the same TI AR7 chip and has LZMA decompressor and build scripts.

Also note that Montavista has released a toolkit which includes 2.4.20 kernel, and 2.6.x might be available soon too.

Igor Mokrushin aka McMCC has published a detailed intsruction how to make a new firmware for this device (Big Thx!)

http://mcmcc.bat.ru/dlinkt/kernel/build_kernel_rus.txt (Build HOWTO in Russian)

http://mcmcc.bat.ru/dlinkt/FW_dsl-xxxt_README.eng.txt (Modified firmware revisions)

Pre-compiled firmware: http://mcmcc.bat.ru/dlinkt/

Serial Console

TI AR7 SoC has two serial UARTs (16550 compatible).

D-Link DSL-G604T has a 5-pin connector, attached to UART_A .

ATTENTION! Do not connect a RS-232 cable directly to the DSL-G604T console port! It uses LVTTL 3.3 volt level RS-232 and it will cause serious damage of the device. You need a LVTTL <--> RS-232 +-12V converter.

It is possible to use a MAXIM MAX3232CPE or LINEARTECH LTC1386CS as converter.

http://www.sensi.org/~alec/images/DlinkDslG604t_Console.jpg Variant2 Schematic

Serial Console BOOT log

AR7 Devices

Unfortunately, this aspect of the TI AR7 isn't well documented.

UPD: Some of addresses are documented in the AR7-specific *.h files from the GPL-ed Linux distributive for this device.

Another source is a TI OMAP documentation. It seems, AR7 SoC peripherals is very similar to the OMAP16xx and OMAP730 application processors , but MIPS instead ARM9-based.

AR7 UART

# cat /proc/tty/driver/serial
serinfo:1.0 driver:5.05c revision:2001-07-08
0: uart:16550A port:A8610E00 irq:15 baud:2258 tx:4514 rx:0 RTS|DTR
1: uart:16550A port:A8610F00 irq:16 tx:0 rx:0 RTS|DTR

C62x DSP

TI TMS320C62x is a fixed-poind Digital Signal Processor core. C62x is based on the VelociTI VLIW architecture developad by TI. C62x is a member of the TI C6000 family.

WiFi/VLYNQ

1130 is a TI TNETW1130, also known as ACX111 chipset, used in DlinkDwl650Plus (PCMCIA), DlinkDwl520plus (PCI) and many other cards.

The TNETW1130 has several interfaces including VLYNQ, TI´s low power, low pin-count, high-speed serial interface. Through these interfaces, the TNETW1130 easily connects to TI´s OMAP1610, OMAP1611 and OMAP730 application processors and AR7 TNETD7300 communication processor.

VLYNQ is a serial communication interface that enables the extension of an internal bus segment to one or more external physical devices. The external devices are mapped into local, physical address space and appears as if they are on the internal bus. the external device must have a VLYNQ interface. The VLYNQ module serializes bus transactions in one device, transfers the serialized data via a VLYNQ port, and de-serializes the transaction in the external device. The VLYNQ interface is described in the TI SPRU768 document. 

# cat /proc/tiwlan/gen_reg
Usage : echo <reg base addr> <offset> <r/w> [<value>] > gen_reg

VLYNQ base : 0xa8611800. Remote offset : 0x80
1130 mem base : 0xa4000000, reg base : 0xa4040000

802.11 Wireless LAN : TI Solutions

TNETW1130 has integrated ARM CPU, and has support for the WPA (SSN), TKIP and AES (CCM) encryption (802.11i), and QoS (802.11e).

Unfortunately, TexasInstruments does not provide any hardware specs for this card. See http://acx100.sourceforge.net/ Source code for the driver is available (see above)

Ethernet

# cat /proc/iomem
...
...
a8612800-a8612fff : eth0
#

Other

CategoryAccessPointHardware

DlinkDslG604t (last edited 2008-05-10 16:08:06 by RyanMcCue)