From DD-WRT Wiki

Revision as of 19:40, 18 February 2007

Installation

Install USB Kernel modules

 ipkg install kmod-usb-uhci // this is for USB 1.1
 ipkg install kmod-usb-core
 ipkg install kmod-usb2
 ipkg install kmod-usb-storage

Manual installation and check

• insert the modules one by one by following commands in a telnet session.

insmod /jffs/lib/modules/2.4.30/usbcore.o
insmod /jffs/lib/modules/2.4.30/ehci-hcd.o
insmod /jffs/lib/modules/2.4.30/scsi_mod.o
insmod /jffs/lib/modules/2.4.30/usb-storage.o
insmod /jffs/lib/modules/2.4.30/sd_mod.o

Check

• See the enabling from dmesg output of a Linksys WRTSL54GS. A SanDisk Cruzer Micro 4G flash drive as recognized.

/ # dmesg
<snip>
<6>ehci_hcd 01:02.2: PCI device 1033:00e0
<6>ehci_hcd 01:02.2: irq 2, pci mem c0181000
<6>usb.c: new USB bus registered, assigned bus number 1
<6>ehci_hcd 01:02.2: USB 2.0 enabled, EHCI 1.00, driver 2003-Dec-29/2.4
<6>hub.c: USB hub found
<6>hub.c: 5 ports detected
<6>hub.c: new USB device 01:02.2-1, assigned address 2
<4>usb.c: USB device 2 (vend/prod 0x781/0x5406) is not claimed by any active driver.
<6>SCSI subsystem driver Revision: 1.00
<6>Initializing USB Mass Storage driver...
<6>usb.c: registered new driver usb-storage
<6>scsi0 : SCSI emulation for USB Mass Storage devices
<0>  Vendor: SanDisk   Model: U3 Cruzer Micro   Rev: 2.18
<0>  Type:   Direct-Access                      ANSI SCSI revision: 02
<0>  Vendor: SanDisk   Model: U3 Cruzer Micro   Rev: 2.18
<0>  Type:   CD-ROM                             ANSI SCSI revision: 02
<7>WARNING: USB Mass Storage data integrity not assured
<7>USB Mass Storage device found at 2
<6>USB Mass Storage support registered.
<0>Attached scsi removable disk sda at scsi0, channel 0, id 0, lun 0
<0>SCSI device sda: 8015505 512-byte hdwr sectors (4104 MB)
<0>sda: Write Protect is off
<6>Partition check:
<6> /dev/scsi/host0/bus0/target0/lun0: p1 p2 p3
/ #

Create a startup script that loads the modules

Create a file, usb.startup in /jffs/etc/config/ directory

~ # mkdir /jffs/etc/config
~ # vi /jffs/etc/config/usb.startup

that contains this (press i once for insert mode):

#!/bin/sh
insmod /jffs/lib/modules/2.4.30/usbcore.o
insmod /jffs/lib/modules/2.4.30/ehci-hcd.o
insmod /jffs/lib/modules/2.4.30/scsi_mod.o
insmod /jffs/lib/modules/2.4.30/usb-storage.o
# remove the dash (#) from the line below if you use USB 1.1
#insmod /jffs/lib/modules/2.4.30/uhci.o
insmod /jffs/lib/modules/2.4.30/sd_mod.o

vi is ended using "ESC" and then :wq

make the script executable:

 chmod +x /jffs/etc/config/usb.startup

For DD-WRT v23 SP1 or below

add the follwing script to startup. It executes on every reboot all *.startup scripts located in /jffs/etc/config/

 console mode
 > ~ # nvram set rc_startup="
 > for I in `/bin/ls /jffs/etc/config/*.startup`
 > do
 >    sh $I &
 > done
 > "
 > ~ # nvram commit
 >
 web interface mode
 for I in `/bin/ls /jffs/etc/config/*.startup`
   do
     sh $I &
 done

This is it. Here's my dmesg from Asus WL-500gP

 dmesg
 SCSI subsystem driver Revision: 1.00
 Initializing USB Mass Storage driver...
 usb.c: registered new driver usb-storage
 USB Mass Storage support registered.
 uhci.c: USB Universal Host Controller Interface driver v1.1
 PCI: Enabling device 01:03.0 (0000 -> 0001)
 uhci.c: USB UHCI at I/O 0x100, IRQ 2
 usb.c: new USB bus registered, assigned bus number 2
 hub.c: USB hub found
 hub.c: 2 ports detected
 PCI: Enabling device 01:03.1 (0000 -> 0001)
 uhci.c: USB UHCI at I/O 0x120, IRQ 2
 usb.c: new USB bus registered, assigned bus number 3
 hub.c: USB hub found
 hub.c: 2 ports detected

kernel modules for filesystems

Now to access FAT/EXT/XFS partitions you must install

 ipkg install kmod-vfat
 ipkg install kmod-ext2
 ipkg install kmod-ext3
 ipkg install kmod-xfs

autoload filesystem modules

Add to /jffs/etc/config/usb.startup (comment out lines you don't need to save memory)

 # FAT
 insmod /jffs/lib/modules/2.4.30/fat.o
 insmod /jffs/lib/modules/2.4.30/vfat.o
 #XFS
 #insmod /jffs/lib/modules/2.4.30/xfs.o
 #EXT2
 #insmod /jffs/lib/modules/2.4.30/ext2.o
 #EXT2
 #insmod /jffs/lib/modules/2.4.30/ext3.o

Now dmesg should show (The example below is from a 80 GB HD)

 Attached scsi disk sda at scsi0, channel 0, id 0, lun 0
 SCSI device sda: 156301488 512-byte hdwr sectors (80026 MB)
 Partition check:
 /dev/scsi/host0/bus0/target0/lun0

Multislot card reader

In order to use a multislot card reader, you must add the following parameter to the scsi_mod in the file /jffs/etc/modules.d/60-usb-storage:

scsi_mod max_scsi_luns=8

Usage

Mounting

mount /dev/scsi/host0/bus0/target0/lun0/part1 /mnt

Performance Testing

With help of the hdparm package you could test your performance. On an Asus WL-500gP(remium) without overclocking you will get

hdparm -tT /dev/scsi/host0/bus0/target0/lun0/part2

Timing cached reads:   188 MB in  2.04 seconds =  92.16 MB/sec
Timing buffered disk reads:   24 MB in  3.19 seconds =   7.52 MB/sec

Please note overclocking wouldn´t get you significant more performance on Asus WL-500gP(remium) Router.

On a WRTSL54G with 4G flash disk

/ # hdparm -tT /dev/scsi/host0/bus0/target0/lun0/part2

/dev/scsi/host0/bus0/target0/lun0/part2:
 Timing cached reads:   148 MB in  2.03 seconds =  72.91 MB/sec
 Timing buffered disk reads:   24 MB in  3.22 seconds =   7.45 MB/sec
/ #

Listing Contents

ls -l /mnt

You can also add the above line to /jffs/etc/config/usb.startup to mount the partition on reboot

# multiple partitions
mkdir /tmp/usb
mkdir /tmp/usb/1
# wait to recognize devices properly
sleep 2
# mount first partition
/bin/mount /dev/scsi/host0/bus0/target0/lun0/part1 /tmp/usb/1
# list its contents
ls -l /tmp/usb/1
# second partition
mkdir /tmp/usb/2
mount /dev/scsi/host0/bus0/target0/lun0/part2 /tmp/usb/2
# list its contents
ls -l /tmp/usb/2