Setting up a data connection over QMI interface using libqmi

Owned by Kareiman Fadly
Mar 13, 2022

Revision and Notes

Date

Owner

Revision

Notes

Date

Owner

Revision

Notes

Mar 8, 2022

 

1.0

Initial release

Table of Contents

 

Introduction

Cellular modules that are based on the Qualcomm chipsets support the QMI interface. The libqmi can be used to establish QMI interface for mini PCIe modules

Step-By-Step

1. Install the libqmi Linux library e.g. by using your system package manager like apt or preferably latest version from source on the Freedesktop pages for libqmi project: https://www.freedesktop.org/wiki/Software/libqmi/

2. Verify that you have the Linux in-kernel qmi_wwan driver installed and attached for the cellular modules QMI interface over USB using:

lsusb -t

Should return driver information, it can look e.g like this:

|__ Port 3: Dev 3, If 4, Class=Vendor Specific Class, Driver=qmi_wwan, 480M

  • You can load the qmi_wwan kernel module by running:

    root@sr-imx8:/home/debian# modprobe qmi_wwan [ 3342.100394] usbcore: registered new interface driver cdc_wdm [ 3342.109771] usbcore: registered new interface driver qmi_wwan

  • The cellular modules QMI control interface are usually named cdc-wdm* e.g.:

Note:

If the driver is not correctly loaded, please verify that the module is set to expose the correct USB endpoints configuration toward the host system and that you have followed the provided guides from the cellular module vendors, regarding how to implement the module in Linux.

3.Install the required packages

4. Use the following command to make sure module is ready:

Should return 'online'. If not, try :

5. Configure the network interface for the raw-ip protocol

6. Set the wwan0 interface to raw mode

7. Restart the interface

8. Once the wwan0 is up, gather the APN information for your SIM card and start the qui network by changing the apn='YOUR_APN',username='YOUR_USERNAME',password='YOUR_PASSWORD' part of the line according to the information of your SIM & operator. If username and password are not required, delete those parameters.

Note:  

Your APN information will vary according to the card you have.

You will get something similar to this:

Once “Network started” is displayed, you can send a DHCP request on the network interface.

9. Acquire an IP number from your provider

You will get something similar to this:

Checking the Connection

Now check the assigned IP address and test the connection

You will get something like this:

Test network connectivity:

You will get something similar to this:

Enjoy your internet connection !

 

SolidRun Ltd.