USS-725 storage driver for linux

Updates

2005-01-24: Igor Mokrushin has been doing some more work on the uss725 driver, and has produced patches for both 2.4 and 2.6:

• linux-2.6.9-usbide-ziv1-uss725-mc1.patch
• uss725_usbide-0.12mc1-2.4.23.patch

See his patch page for updates.

2002-11-21: Good news! Nicolas Planel has picked up where I left off and has now produced a patch that works for ATA disks (no cdroms yet): uss725-2.4.20-rc2.patch. Nicolas' home page is here.

The USS-725 is an ASIC designed by In-System Design Inc. that acts as a USB-to-parallel bridge and which is used for connecting printers to USB. It also has rudimentary support for ATA in PIO mode, using a sequencer to perform register access and data transfer operations.

Before the ISD-200 USB/ATA chip was created, In-System wrote a set of elaborate windows drivers, a.k.a the "Falstaff" drivers, to enable the USS-725 chip to talk to ATA/ATAPI devices. Parts of these drivers have now been released and I'm working on producing a Linux driver.

Storage products I've heard are using the USS-725 chip:

• In-Systems ISD-110/111 SmartBoard for storage
• Archos Mini-CDRW drive (0x05ab/0x081a)
• ARC USB Cable (0x05ab/0x081a)
• Mem-Up USB harddisk
• Fantom Drives USB harddisk (blue & white models, graphite uses the OnSpec chip)
• Addonics ExDrive
• Planex ExtremeDrive portable USB HDD case RX-25H
• XtraDisk USB harddrive enclosure
• Pockey drive
• Mapower Map-Q21S HDD case (0x05ab/0x0202)
• Cristie's Travan 20 USB Tape Drive

Status

2001-11-13: Coming along nicely. Device initialization nearly works now, and the driver is already a whopping 1200 lines of code...

Files

• The USS-725 datasheet (pdf, 256 kB)
• The windows driver source code (zipped, 36 kB)
• patch-uss725-2.4.14.gz - The state of the code as of 2001-12-09. Apply to the drivers/usb directory of linux 2.4.14. NOTE: This code does not work, intended for developers only!

/proc/bus/usb/devices entry

T:  Bus=01 Lev=02 Prnt=03 Port=04 Cnt=02 Dev#=  8 Spd=12  MxCh= 0
D:  Ver= 1.00 Cls=ff(vend.) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=05ab ProdID=0200 Rev= 1.10
S:  Product=USB to IDE Adapter
S:  SerialNumber=7e0ce173-3113-11d4-9ab9-d0a535178c43
C:* #Ifs= 1 Cfg#= 1 Atr=c0 MxPwr=  0mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=ff(vend.) Sub=00 Prot=ff Driver=usb-storage
E:  Ad=01(O) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
I:  If#= 0 Alt= 1 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=ff Driver=usb-storage
E:  Ad=01(O) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
E:  Ad=82(I) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
I:  If#= 0 Alt= 2 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=ff Driver=usb-storage
E:  Ad=01(O) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
E:  Ad=82(I) Atr=02(Bulk) MxPS=  64 Ivl=  0ms