1. Article purpose[edit source]
The purpose of this article is to explain how to configure an USB remote server with STM32MP157C-DK2, managed by Linux on Cortex®-A7.
The Goal are to transform STM32MP157C-DK2 board on an USB remote server, manage USB device on a PC while the USB device are connected to a remote server on network.
|-----------|
___________________ /-----| PC 1 | Debug session via ST-LINK (USB2 over network)
USB1 (webcam)-- | USB REMOTE | / |___________|
\ | SERVER |======== network =========== |-----------|
/ | STM32MP157C-DK2 | \ | PC 2 | Preview camera via usb camera (USB1 over network)
USB2 (STLINK)-- |_________________| \-----|___________|
To configure a STM32MP157C-DK2 board on an USB remote server we will use USBIP to
This article provides step-by-step instructions to:
- explain how to transform a linux board on an USB remote server with USBIP
- configure Linux software to enable USBIP server (aka USB remote server),
- configure PC client to connect to USBIP server.
- to further, manage power for USB device on server with uhubctl tool
2. Configure STM32 MPU board with USBIP[edit source]
2.1. Overview[edit source]
USB/IP Project aims to develop a general USB device sharing system over IP network. To share USB devices between computers with their full functionality, USB/IP encapsulates "USB I/O messages" into TCP/IP payloads and transmits them between computers. [1]
2.2. step by step on server[edit source]
The Installation of USBIP server are made on Linux embedded board.
2.2.1. Manual setup[edit source]
Before to use the usbip command you need to load the kernel modules associated to usbip:
modprobe usbip-core modprobe usbip-host
Start the usbip server:
usbipd -D
To render available an usb device connected to Linux embedded board you need to bind the device.
List available usb device:
usbip list -l - busid 2-1.1 (03f0:e207) HP, Inc : unknown product (03f0:e207)
Bind this specific device to be visible by a PC client (here device 2-1.1):
usbip bind -b 2-1.1
(to automate the binding of new usb device, see the next section Automated setup)
2.2.2. Automated setup[edit source]
- Automate server startup via systemd
Create on board a service dedicated to start usbip server
Content of /lib/systemd/system/usbip.service
[Unit] Description=USB-IP Bindind After=network.target Wants=network.target [Service] Type=forking ExecStartPre=-/sbin/modprobe usbip-core ExecStartPre=-/sbin/modprobe usbip-host ExecStart=/usr/sbin/usbipd -D ExecStop=/usr/sbin/stm32mp-usbip-bind-unbind.sh unload [Install] WantedBy=multi-user.target
Start systemd usbip service:
systemctl daemon-reload systemctl start usbip
- Automate binding of new usb device
The binding of new usb device can be made by a script which bind or unbind the usb device following if it's plugged or unplugged.
This script must be called by an udev rules for the case of plug/unplug of device.
Content of script: /usr/sbin/stm32mp-usbip-bind-unbind.sh
#!/bin/sh -
#echo "Parameter number $#" >> /tmp/usbip.log
action=$1
devpath=$2
#echo "Parameter: $1" >> /tmp/usbip.log
#echo "Parameter: $2" >> /tmp/usbip.log
case $1 in
unload)
modprobe -r usbip-core
modprobe -r usbip-host
kill -9 `pgrep usbipd`
exit 0
;;
esac
subpath=$(echo $2 | sed "s|.*/\([^/]*\)|\1|")
#echo "subpath >$subpath<" >> /tmp/usbip.log
if $(echo $subpath | grep -q ":");
then
#echo "No valid path" >> /tmp/usbip.log
exit 0
fi
# if usbip-core are not loaded, do nothing
if [ -z "$(cat /proc/modules | grep usbip_core)" ]; then
#echo "no module usbip_core loaded" >> /tmp/usbip.log
exit 0
fi
case $1 in
add)
#echo ">>> bind $subpath" >> /tmp/usbip.log
usbip bind -b $subpath
;;
remove)
#echo "<<< unbind $subpath" >> /tmp/usbip.log
usbip unbind -b $subpath
;;
esac
Content of udev rules: /etc/udev/rules.d/99-usb-usbip.rules
ACTION=="remove", SUBSYSTEM=="usb", RUN+="/usr/sbin/stm32mp-usbip-bind-unbind.sh remove %p" ACTION=="add", SUBSYSTEM=="usb", DRIVER=="usb", RUN+="/usr/sbin/stm32mp-usbip-bind-unbind.sh add %p"
2.3. step by step on PC client[edit source]
2.3.1. On Windows[edit source]
An USBIP client exist for windows and are available via Github usbip-win
2.3.1.1. Installation[edit source]
For installation, follow instruction specified on README.md.
2.3.1.2. Usage[edit source]
User action:
- List usb device available on specificy server
usbip.exe list -l -r <usbip server ip>
- Attach an usb device available on specificy server (here 2-1)
usbip.exe list -r <usbip server ip> -b 2-1
- List attached usb device on host PC
usbip.exe port
- Detach a specific attached usb device on host PC
List attached device on host PC and detach it (here 00) usbip detach -p 00
2.3.2. On Linux[edit source]
2.3.2.1. Installation[edit source]
On Ubuntu, you need to install some pre-requisite package:
sudo apt-get install sysfsutils libwrap0-dev libglib2.0-dev libtool automake autoconf pkg-config linux-tools-generic
For having a translation of usb device name and ID you need to insatll a specific harware data base
wget http://www.linux-usb.org/usb.ids sudo mkdir -p /usr/share/hwdata/ sudo cp usb.ids /usr/share/hwdata/
2.3.2.2. Usage[edit source]
Before to use the usbip command you need to load the kernel modules associated to usbip:
sudo modprobe usbip-core modprobe vhci-hcd
- List usb remote device available on specific server:
sudo usbip list -r <server IP>
- Attach an usb remote device available on specific server:
sudo usbip attach -r <server IP> -b <USB ID>
- Detach a specific attached usb device on host PC
List usb device attached
sudo usbip port
Detach specific usb device attached as 00
sudo usbip detach -p 00
3. Configure STM32 MPU board to add usb power management with uhubctl[edit source]
3.1. Overview[edit source]
uhubctl is utility to control USB power per-port on smart USB hubs. Smart hub is defined as one that implements per-port power switching.[2]
3.2. Usage[edit source]
uhubctl Current status for hub 2-1 [0424:2514] Port 1: 0507 power highspeed suspend enable connect [03f0:e207 Hewlett Packard HP Webcam HD 2300] Port 2: 0100 power Port 3: 0100 power Port 4: 0100 power Current status for hub 2 [1d6b:0002 Linux 5.9.0-rc4 ehci_hcd EHCI Host Controller 5800d000.usbh-ehci] Port 1: 0503 power highspeed enable connect [0424:2514] Port 2: 0100 power Current status for hub 1 [1d6b:0002 Linux 5.9.0-rc4 dwc2_hsotg DWC OTG Controller 49000000.usb-otg] Port 1: 0000 off
On hub 2-1 Port 1 a usb webcam are plugged:
cat /sys/class/video4linux/video1/name HP Webcam HD 2300: HP Webcam HD
To power Off the usb webcam connected on this port:
uhubctl -a off -p 1 -l 2-1 Current status for hub 2-1 [0424:2514] Port 1: 0507 power highspeed suspend enable connect [03f0:e207 Hewlett Packard HP Webcam HD 2300] Sent power off request New status for hub 2-1 [0424:2514] Port 1: 0000 off uhubctl Current status for hub 2-1 [0424:2514] Port 1: 0503 power highspeed enable connect [03f0:e207] Port 2: 0100 power Port 3: 0100 power Port 4: 0100 power Current status for hub 2 [1d6b:0002 Linux 5.9.0-rc4 ehci_hcd EHCI Host Controller 5800d000.usbh-ehci] Port 1: 0503 power highspeed enable connect [0424:2514] Port 2: 0100 power Current status for hub 1 [1d6b:0002 Linux 5.9.0-rc4 dwc2_hsotg DWC OTG Controller 49000000.usb-otg] Port 1: 0000 off
To power On the usb webcam connected on this port:
uhubctl -a on -p 1 -l 2-1 Current status for hub 2-1 [0424:2514] Port 1: 0507 power highspeed suspend enable connect [03f0:e207 Hewlett Packard HP Webcam HD 2300] Sent power on request New status for hub 2-1 [0424:2514] Port 1: 0503 power highspeed enable connect [03f0:e207 Hewlett Packard HP Webcam HD 2300] uhubctl Current status for hub 2-1 [0424:2514] Port 1: 0507 power highspeed suspend enable connect [03f0:e207 Hewlett Packard HP Webcam HD 2300] Port 2: 0100 power Port 3: 0100 power Port 4: 0100 power Current status for hub 2 [1d6b:0002 Linux 5.9.0-rc4 ehci_hcd EHCI Host Controller 5800d000.usbh-ehci] Port 1: 0503 power highspeed enable connect [0424:2514] Port 2: 0100 power Current status for hub 1 [1d6b:0002 Linux 5.9.0-rc4 dwc2_hsotg DWC OTG Controller 49000000.usb-otg] Port 1: 0000 off