Realtek R8712U USB WiFi Integration
Introduction
This white paper will show how to integrate the Realtek RTL8191SU chipset found in the D-Link DWA-131 USB WiFi dongle with a LeopardBoard DM368. Although the process is given for a specific board and wifi adapter, it is possible to translate it to others boards and wifi adapters.
If you use the D-Link DWA-131 or some other dongle that has the RTL8191SU chipset, the process will be very similar.
Using lsusb on a desktop machine, the D-Link DWA-131 is identified as (simplified):
07d1:3303 D-Link System DWA-131 rev.A1 Realtek RTL8192SU
The RTL8192SU chipset is supported by the Linux r8712u driver. The Realtek r8712u version 2.6.6.0.20120403 driver supports Linux 2.6 vintage kernels.
There is also a DLink DWA-131 Linux Driver available.
Driver integration
Create pristine driver tarball
# setup the kernel patch file cd $DEVDIR/kernel quilt new 8712u-driver.patch # extract the part of the zip file we need mkdir -p $DEVDIR/tmp cd $DEVDIR/tmp curl -f -L ftp://WebUser:Lc9FuH5r@207.232.93.28/cn/wlan/RTL819xSU_usb_linux_v2.6.6.0.20120405.zip > RTL819xSU_usb_linux_v2.6.6.0.20120405.zip unzip RTL819xSU_usb_linux_v2.6.6.0.20120405.zip cd rtl8712_8188_8191_8192SU_usb_linux_v2.6.6.0.20120405/driver tar -xzf rtl8712_8188_8191_8192SU_usb_linux_v2.6.6.0.20120405.tar.gz mv rtl8712_8188_8191_8192SU_usb_linux_v2.6.6.0.20120405 8712u # add the driver to the kernel tree mv 8712u $DEVDIR/kernel/linux-*/drivers/net/wireless cd $DEVDIR/kernel KER=`ls -d linux-*` # add driver files to patch file DRIVER_FILES=`find $KER/drivers/net/wireless/8712u -type f` mv $KER/drivers/net/wireless/8712u $KER/drivers/net/wireless/8712u.new echo $DRIVER_FILES | xargs quilt add mv $KER/drivers/net/wireless/8712u.new $KER/drivers/net/wireless/8712u quilt add $KER/drivers/net/wireless/Makefile $KER/drivers/net/wireless/Kconfig cd $KER/drivers/net/wireless echo 'obj-$(CONFIG_RTL8712U) += 8712u/' >> Makefile # replace endif # WLAN with line to source the 8712u driver sed -i.bak -e 's!^endif.*!source "drivers/net/wireless/8712u/Kconfig"!' Kconfig echo 'endif # WLAN' >> Kconfig quilt refresh
Create 2.6.32 backport tarball
The 2.6.32 kernel doesn't support pmksa or pmkids, so those features need to be included only for newer kernels.
Index: kernel/linux-2.6.32.17-psp03.01.01.39/drivers/net/wireless/8712u/os_dep/linux/ioctl_cfg80211.c =================================================================== --- kernel.orig/linux-2.6.32.17-psp03.01.01.39/drivers/net/wireless/8712u/os_dep/linux/ioctl_cfg80211.c 2012-11-27 10:37:26.465000634 -0700 +++ kernel/linux-2.6.32.17-psp03.01.01.39/drivers/net/wireless/8712u/os_dep/linux/ioctl_cfg80211.c 2012-11-27 10:39:44.100915436 -0700 @@ -1876,6 +1876,7 @@ return 0; } +#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,37)) static int cfg80211_rtw_set_pmksa(struct wiphy *wiphy, struct net_device *netdev, struct cfg80211_pmksa *pmksa) @@ -1916,6 +1917,7 @@ //return iwm_send_pmkid_update(iwm, &pmksa, IWM_CMD_PMKID_FLUSH); return 0; } +#endif // (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,37)) static int cfg80211_rtw_mgmt_tx(struct wiphy *wiphy, struct net_device *dev, #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,38)) @@ -2203,10 +2205,10 @@ .set_tx_power = cfg80211_rtw_set_txpower, .get_tx_power = cfg80211_rtw_get_txpower, .set_power_mgmt = cfg80211_rtw_set_power_mgmt, +#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,37)) .set_pmksa = cfg80211_rtw_set_pmksa, .del_pmksa = cfg80211_rtw_del_pmksa, .flush_pmksa = cfg80211_rtw_flush_pmksa, -#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,37)) .mgmt_tx = cfg80211_rtw_mgmt_tx, .mgmt_frame_register = cfg80211_rtw_mgmt_frame_register, #elif (LINUX_VERSION_CODE>=KERNEL_VERSION(2,6,34) && LINUX_VERSION_CODE<=KERNEL_VERSION(2,6,35)) @@ -2290,9 +2292,8 @@ wiphy->max_scan_ssids = RTW_SSID_SCAN_AMOUNT; wiphy->max_scan_ie_len = RTW_SCAN_IE_LEN_MAX; - wiphy->max_num_pmkids = RTW_MAX_NUM_PMKIDS; - #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,38)) + wiphy->max_num_pmkids = RTW_MAX_NUM_PMKIDS; wiphy->max_remain_on_channel_duration = RTW_MAX_REMAIN_ON_CHANNEL_DURATION; #endif
Hardware configuration
Make sure your hardware is configured in USB host mode.
Board's driver configuration
In order to get you board ready to run the driver for the wifi adapter you must enable various kernel features and applications. You can check that you have all the packages enabled correctly by running:
egrep 'CONFIG_NET[= ]|CONFIG_WIRELESS[= ]|CONFIG_MAC80211[= ]|CONFIG_EMBEDDED|CONFIG_WLAN[= ]|CONFIG_WLAN_80211|CONFIG_CFG80211[= ]|CONFIG_MAC80211_RC_MINSTREL|CONFIG_RTL8712U|CONFIG_FS_APPS_OPENSSL|CONFIG_FS_APPS_WPASUPPLICANT|CONFIG_FS_APPS_WIRELESS_TOOLS|CONFIG_RTL8182U' $DEVDIR/bsp/mach/bspconfig
with expected output:
CONFIG_FS_APPS_OPENSSL=y CONFIG_FS_APPS_WIRELESS_TOOLS=y CONFIG_FS_APPS_WPASUPPLICANT=y CONFIG_EMBEDDED=y CONFIG_NET=y CONFIG_WIRELESS=y CONFIG_CFG80211=y CONFIG_MAC80211=y CONFIG_MAC80211_RC_MINSTREL=y CONFIG_WLAN=y CONFIG_WLAN_80211=y CONFIG_RTL8712U=m
Debug FS configuration
You can add some debugging information files via debugfs:
egrep 'CFG80211_DEBUGFS|MAC80211_DEBUGFS' $DEVDIR/bsp/mach/bspconfig
with expected output:
CONFIG_CFG80211_DEBUGFS=y CONFIG_MAC80211_DEBUGFS=y
Hardware bring
I started by booting the board without the DWA-131 installed and without the driver loaded.
Install DWA-131 WiFi USB dongle
Install dongle, run
lsusb
Expected output:
Bus 001 Device 001: ID 1d6b:0002 Bus 001 Device 003: ID 07d1:3303
The 07d1:3303 is the DWA-131 dongle.
Software bring up
Install 8712u kernel module
Run:
modprobe 8712u
Expected output:
==DriverVersion: v2.6.6.0.20120405== register rtl8712_netdev_ops to netdev_ops rtw_wdev_alloc 8712_usb_endpoint_descriptor(0): bLength=7 bDescriptorType=5 bEndpointAddress=83 wMaxPacketSize=200 bInterval=0 8712_usb_endpoint_descriptor(1): bLength=7 bDescriptorType=5 bEndpointAddress=4 wMaxPacketSize=200 bInterval=0 8712_usb_endpoint_descriptor(2): bLength=7 bDescriptorType=5 bEndpointAddress=6 wMaxPacketSize=200 bInterval=0 8712_usb_endpoint_descriptor(3): bLength=7 bDescriptorType=5 bEndpointAddress=d wMaxPacketSize=200 bInterval=0 8712u : USB_SPEED_HIGH nr_endpoint=4 Boot from EFUSE Autoload OK!! CustomerID = 0x 0 MAC Address from efuse= 14-d6-4d-10-9d-79 cfg80211_rtw_set_power_mgmt usbcore: registered new interface driver r871x_usb_drv
Verify wlan0 exists
Make sure Linux network interface and wireless LAN interface are both found
ifconfig wlan0 iwconfig wlan0
You should get output like:
wlan0 Link encap:Ethernet HWaddr 14:D6:4D:10:9D:79
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
and
wlan0 unassociated Nickname:"rtl_wifi"
Mode:Auto Access Point: Not-Associated Sensitivity:0/0
Retry:off RTS thr:off Fragment thr:off
Encryption key:off
Power Management:off
Link Quality:0 Signal level:0 Noise level:0
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
Power on WiFi sub-system
ifconfig wlan0 up
No output will be generated if successful, unless you have debug enabled.
Ad hoc mode
Ad hoc WiFi networking allows the target device to wait for a host device to connect directly to the target, without the use of a Wireless Access Point (WAP).
Target configuration
Configure DHCP server
When a host connects to the target, it will likely need an IP address. You can run a DHCP server on the target to so the ad hoc network has a DHCP server. You can add something similar to the following to the /etc/dhcpd.conf file.
subnet 10.100.0.0 netmask 255.255.255.0 {
range 10.100.0.10 10.100.0.100;
option domain-name "example.org";
option domain-name-servers dns1.example.org;
option routers 10.100.0.1;
option broadcast-address 10.100.0.1;
default-lease-time 600;
max-lease-time 7200;
}
Configure wifi for ad hoc
iwconfig wlan0 mode ad-hoc iwconfig wlan0 channel 4 iwconfig wlan0 essid 'dm368' ifconfig wlan0 10.100.0.1 netmask 255.255.255.0 route add default wlan0
Start DHCP server
touch /var/db/dhcpd.leases dhcpd &
Host configuration
On the host, scan for wireless devices and access points. Select the ESSID name used by the target (dm36 in the example above).
Infrastructure mode
Infrastructure mode requires the use of a Wireless Access Point (WAP) where devices connected to the WAP.
Scan for access points
iwlist wlan0 scan
which lists access points that are in range, like:
wlan0 Scan completed :
Cell 01 - Address: 00:26:5A:A4:EC:44
ESSID:"RGA"
Protocol:IEEE 802.11bgn
Mode:Master
Frequency:2.412 GHz (Channel 1)
Encryption key:on
Bit Rates:150 Mb/s
Extra:wpa_ie=dd1a0050f20101000050f20202000050f2040050f20201000050f202
IE: WPA Version 1
Group Cipher : TKIP
Pairwise Ciphers (2) : CCMP TKIP
Authentication Suites (1) : PSK
Extra:rsn_ie=30180100000fac020200000fac04000fac020100000fac020000
IE: IEEE 802.11i/WPA2 Version 1
Group Cipher : TKIP
Pairwise Ciphers (2) : CCMP TKIP
Authentication Suites (1) : PSK
Signal level=32/100
Cell 02 - Address: B8:C7:5D:03:68:3F
ESSID:"Futuris"
Protocol:IEEE 802.11bgn
Mode:Master
Frequency:2.412 GHz (Channel 1)
Encryption key:on
Bit Rates:144 Mb/s
Extra:wpa_ie=dd160050f20101000050f20201000050f20201000050f202
IE: WPA Version 1
Group Cipher : TKIP
Pairwise Ciphers (1) : TKIP
Authentication Suites (1) : PSK
Extra:rsn_ie=30180100000fac020200000fac04000fac020100000fac020000
IE: IEEE 802.11i/WPA2 Version 1
Group Cipher : TKIP
Pairwise Ciphers (2) : CCMP TKIP
Authentication Suites (1) : PSK
Signal level=10/100
Attaching WiFi to access point
Security disabled
iwconfig wlan0 essid "Hawley"
WEP security
iwconfig wlan0 essid "Hawley" iwconfig wlan0 key 0001020304
WPA security
mkdir -p /etc/wpa_supplicant
cat <<EOF >/etc/wpa_supplicant/wpa_supplicant.conf
# Example wpa_supplicant
network={
ssid="Baily"
psk="very secret passphrase"
priority=5
}
EOF
wpa_supplicant -d -iwlan0 -c/etc/wpa_supplicant/wpa_supplicant.conf -Dwext &
With debug output enabled, you will have lots of information on what is not working if you run into a problem.
Verifying access point association
You can check you are associated with an access point using
iwconfig wlan0