Sierra Wireless EM7455, MBIM connect

[Fabian Schörghofer]

This is my attempt to connect with umbim and OpenWrt:

Device plugged in:

Linux OpenWrt 4.1.20 #1 Mon Apr 18 16:04:52 UTC 2016 mips GNU/Linux

root at OpenWrt:/# [ 3499.696668] usb 1-1: new high-speed USB device
number 4 using ehci-platform
[ 3499.847624] usb 1-1: config 1 has an invalid interface number: 12
but max is 3
[ 3499.854927] usb 1-1: config 1 has an invalid interface number: 13
but max is 3
[ 3499.862243] usb 1-1: config 1 has an invalid interface number: 13
but max is 3
[ 3499.869533] usb 1-1: config 1 has no interface number 1
[ 3499.874801] usb 1-1: config 1 has no interface number 2
[ 3499.885599] qcserial 1-1:1.0: Qualcomm USB modem converter detected
[ 3499.892407] usb 1-1: Qualcomm USB modem converter now attached to ttyUSB0
[ 3499.917052] qcserial 1-1:1.3: Qualcomm USB modem converter detected
[ 3499.923796] usb 1-1: Qualcomm USB modem converter now attached to ttyUSB1
[ 3499.946248] cdc_mbim 1-1:1.12: cdc-wdm0: USB WDM device
[ 3499.953031] cdc_mbim 1-1:1.12 wwan0: register 'cdc_mbim' at
usb-ehci-platform-1, CDC MBIM, 0a:22:35:a2:a5:29
[ 3499.966301] 8021q: adding VLAN 0 to HW filter on device wwan0

Leaving the device open with: cat >/dev/cdc-wdm0

root at OpenWrt:/# umbim -n -d /dev/cdc-wdm0 caps
  devicetype: 0003 - remote
  cellularclass: 0001
  voiceclass: 0001 - no-voice
  simclass: 0002
  dataclass: 003C
  smscaps: 0003
  controlcaps: 0001
  maxsessions: 0008
  deviceid: 35432407xxxxxxx
  firmwareinfo: SWI9X30C_02.08.02.00
  hardwareinfo: EM7455

Somehow umbim (or the modem) thinks that it needs pin2, but I have
deactivated the pin with a normal mobile phone:

root at OpenWrt:/# umbim -n -d /dev/cdc-wdm0 pinstate
required pin: 3 - pin2
remaining attempts: 3

I then try to connect:

root at OpenWrt:/# umbim -v -n -d /dev/cdc-wdm0 connect
sending (16): 01 00 00 00 10 00 00 00 01 00 00 00 00 04 00 00
  header_type: 0001
  header_length: 0010
  header_transaction: 0001
reading (16): 01 00 00 80 10 00 00 00 01 00 00 00 00 00 00 00
  header_type: 80000001
  header_length: 0010
  header_transaction: 0001
sending (108): 03 00 00 00 6c 00 00 00 02 00 00 00 01 00 00 00 00 00
00 00 a2 89 cc 33 bc bb 8b 4f b6 b0 13 3e c2 aa e6 df 0c 00 00 00 01
00 00 00 3c 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 7e 5e 2a 7e 4e 6f 72 72 73 6b 65 6e 7e 5e 2a 7e
  header_type: 0003
  header_length: 006C
  header_transaction: 0002
reading (48): 03 00 00 80 30 00 00 00 02 00 00 00 01 00 00 00 00 00 00
00 a2 89 cc 33 bc bb 8b 4f b6 b0 13 3e c2 aa e6 df 0c 00 00 00 0e 00
00 00 00 00 00 00
  header_type: 80000003
  header_length: 0030
  header_transaction: 0002
  command_id: 000C
  status_code: 000E
sending (16): 02 00 00 00 10 00 00 00 03 00 00 00 01 00 00 00
  header_type: 0002
  header_length: 0010
  header_transaction: 0003
reading (16): 02 00 00 80 10 00 00 00 03 00 00 00 00 00 00 00
  header_type: 80000002
  header_length: 0010
  header_transaction: 0003

But the parameter 'config' returns empty...

root at OpenWrt:/# umbim -n -d /dev/cdc-wdm0 config
root at OpenWrt:/#

Or with debug information:

root at OpenWrt:/# umbim -v -n -d /dev/cdc-wdm0 config
sending (16): 01 00 00 00 10 00 00 00 01 00 00 00 00 04 00 00
  header_type: 0001
  header_length: 0010
  header_transaction: 0001
reading (16): 01 00 00 80 10 00 00 00 01 00 00 00 00 00 00 00
  header_type: 80000001
  header_length: 0010
  header_transaction: 0001
sending (108): 03 00 00 00 6c 00 00 00 02 00 00 00 01 00 00 00 00 00
00 00 a2 89 cc 33 bc bb 8b 4f b6 b0 13 3e c2 aa e6 df 0f 00 00 00 00
00 00 00 3c 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  header_type: 0003
  header_length: 006C
  header_transaction: 0002
reading (48): 03 00 00 80 30 00 00 00 02 00 00 00 01 00 00 00 00 00 00
00 a2 89 cc 33 bc bb 8b 4f b6 b0 13 3e c2 aa e6 df 0f 00 00 00 10 00
00 00 00 00 00 00
  header_type: 80000003
  header_length: 0030
  header_transaction: 0002
  command_id: 000F
  status_code: 0010
sending (16): 02 00 00 00 10 00 00 00 03 00 00 00 01 00 00 00
  header_type: 0002
  header_length: 0010
  header_transaction: 0003
reading (16): 02 00 00 80 10 00 00 00 03 00 00 00 00 00 00 00
  header_type: 80000002
  header_length: 0010
  header_transaction: 0003

And udhcpc is not returning with an IP address:

root at OpenWrt:/# udhcpc -i wwan0 -n
udhcpc (v1.24.2) started
Sending discover...
Sending discover...
Sending discover...
No lease, failing

Although I am not sure if this is the "intended" way of assigning the
IP to an interface.

Are MBIM-Sessions surviving a power cycle of the modem?