Difference between revisions of "USB Gadget"

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(no gadget on APF27)
m (To emulate a serial link)
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===To emulate a serial link===
 
===To emulate a serial link===
 
* On your Host PC:
 
* On your Host PC:
 +
<pre class="host">
 
  $ sudo modprobe usbserial vendor=0x0525 product=0xA4A6
 
  $ sudo modprobe usbserial vendor=0x0525 product=0xA4A6
 +
</pre>
 
or you can automate it by modifying ''/etc/modprobe.d/options'' file (Tested on *Ubuntu):
 
or you can automate it by modifying ''/etc/modprobe.d/options'' file (Tested on *Ubuntu):
  # vim /etc/modprobe.d/options
+
<pre class="host">
 +
  $ sudo vim /etc/modprobe.d/options
 
   ...
 
   ...
 
   options usbserial vendor=0x0525 product=0xA4A6
 
   options usbserial vendor=0x0525 product=0xA4A6
 
+
</pre>
 
* on your APF:
 
* on your APF:
 +
<pre class="apf">
 
  # mknod /dev/ttygserial c 127 0  (if not already existing)
 
  # mknod /dev/ttygserial c 127 0  (if not already existing)
 
  # modprobe g_serial
 
  # modprobe g_serial
<pre class="apf">
 
 
  gs_bind: Gadget Serial v2.2 bound
 
  gs_bind: Gadget Serial v2.2 bound
 
  gs_module_init: Gadget Serial v2.2 loaded
 
  gs_module_init: Gadget Serial v2.2 loaded

Revision as of 19:33, 16 February 2010

Instructions to use the USB device (or OTG) port of your Armadeus board to communicate with your PC; ie see your board from your PC like an USB device.

Note Note: These instructions are currently only possible on APF9328 based systems: APF27s have currently no baseboard with USB device/OTG connector and corresponding Linux drivers are not integrated in Armadeus kernel


Introduction

You can connect your APF9328 board to your PC using its USB Device port and it can be "enumerated" as most common USB devices (depending on the type of communication you want to use):

  • serial device
  • net device
  • mass storage device

Installation

  • The drivers are now installed by default (since armadeus-3.0)
  • you should have following modules in your kernel source tree:
drivers/usb/gadget/gadgetfs.ko        For test
drivers/usb/gadget/g_ether.ko         Ethernet emulation on USB
drivers/usb/gadget/g_file_storage.ko  Mass storage
drivers/usb/gadget/g_serial.ko        Serial emulation on USB
drivers/usb/gadget/g_zero.ko          For test

Usage

To emulate a mass storage device:

  • create or get a "backing storage file" (for example)
  • copy this file (uncompressed) in the /tmp directory of your board (here my Host PC has 192.168.0.20 as IP @):
 # tftp -g -r backing_file.gz -l /tmp/backing_file.gz 192.168.0.20
 # gunzip /tmp/backing_file.gz
  • load g_file_storage module:
 # modprobe g_file_storage file=/tmp/backing_file
 g_file_storage gadget: File-backed Storage Gadget, version: 28 November 2005
 g_file_storage gadget: Number of LUNs=1
 g_file_storage gadget-lun0: ro=0, file: /tmp/backing_file
  • connect target's USB cable to your PC and,

On your Linux Host:

  • If you have a recent Linux distribution, your device should be automatically mounted. Otherwise:
    • as root, launch dmesg and find the /dev/sdaX device assigned to your board:
... usb 1-1.4: new full speed USB device using uhci_hcd and address 7
... usb 1-1.4: configuration #1 chosen from 1 choice
... scsi1 : SCSI emulation for USB Mass Storage devices
...    Vendor: Linux     Model: File-Stor Gadget  Rev: 0314
...    Type:   Direct-Access                      ANSI SCSI revision: 02
...  SCSI device sda: 8192 512-byte hdwr sectors (4 MB)
...  sda: Write Protect is off
...  SCSI device sda: 8192 512-byte hdwr sectors (4 MB)
...  sda: Write Protect is off
...   sda: sda1
...  sd 1:0:0:0: Attached scsi disk sda
...  sd 1:0:0:0: Attached scsi generic sg0 type 0
    • then mount the device and enjoy file sharing:
 $ sudo mount /dev/sda1 /mnt/tmp
 $ cd /mnt/tmp
 $ showimage /mnt/tmp/test.jpg

To emulate a serial link

  • On your Host PC:
 $ sudo modprobe usbserial vendor=0x0525 product=0xA4A6

or you can automate it by modifying /etc/modprobe.d/options file (Tested on *Ubuntu):

 $ sudo vim /etc/modprobe.d/options
  ...
  options usbserial vendor=0x0525 product=0xA4A6
  • on your APF:
 # mknod /dev/ttygserial c 127 0   (if not already existing)
 # modprobe g_serial
 gs_bind: Gadget Serial v2.2 bound
 gs_module_init: Gadget Serial v2.2 loaded
  • then connect the USB cable between your PC and your APF and you should see on your Host:
 $ tail -f /var/log/messages
 Nov 27 22:53:50 ...  usb 1-1.4: new full speed USB device using uhci_hcd and address 7
 Nov 27 22:53:50 ...  usb 1-1.4: configuration #1 chosen from 1 choice
 Nov 27 22:53:50 ...  usbserial_generic 1-1.4:1.0: generic converter detected
 Nov 27 22:53:50 ...  usb 1-1.4: generic converter now attached to ttyUSB0
  • you should now be able to send/receive data through /dev/ttyUSB0 (PC) and /dev/ttygserial (APF):
 [armadeus]$ echo "COUCOU" > /dev/ttyUSB0
 # cat /dev/ttygserial
 COUCOUC

To emulate an Ethernet link

  • On your Target:
 # modprobe g_ether
 ether gadget: using random self ethernet address
 ether gadget: using random host ethernet address
 usb0: Ethernet Gadget, version: May Day 2005
 usb0: using imx_udc, OUT ep2out-bulk IN ep1in-bulk STATUS ep4in-int
 usb0: MAC be:df:31:95:16:e0
 usb0: HOST MAC 3e:86:1e:94:eb:84
 usb0: RNDIS ready
  • On your PC:
 $ sudo modprobe cdc_ether
  • If someone knows how to go further.... :-)

Links