QMI - Qualcomm Messaging Interface

QMI Big Picture

• Inter-Processor Communication: QMI is an IPC protocol used between software components hosted among a network of processors within a System-On-Chip (SoC).
• Client-Server Model: Based on a client-server communication model.
• Asynchronous Interface: Built using an asynchronous interface model.
• Backward Compatibility: Supports backward compatibility inherently.
• Layered Implementation: Follows a layered implementation.

Client-Server Communication Model

• Model: QMI is based on a client-server communication model.
• Hosting: A client or a service can be hosted in any processor (nodes, subsystems).
• Service Identification: A service is identified by a client using a unique service name (<service>:<instance> combination). The <service> field is a 32-bit value assigned by the QMI CCB team, and the <instance> field is a 32-bit value assigned by the service owners.
• Service Name: Equivalent to a domain name on the internet.

QMI Framework

• Skeleton: Enables sending and receiving QMI messages between multiple processors.
• Mailman Role: Acts as a mailman, not interpreting or tampering with the contents of the QMI messages.
• APIs: Provides APIs to implement clients and services.
• Layering Model: Strictly follows a layering model, with each layer performing well-defined operations and being decoupled from the implementation of its adjacent layer.

Building

To build the QMI project, follow these steps:

1. Clone the QMI project.

2. Set up the proper toolchain for x86/ARM.

3. Navigate to the project directory:

   cd qmi_framework

4. Build the project:

   autoreconf --install
   ./configure
   make
   make install

   By default, ./configure command will configure the project to install compiled libraries and binaires in system's /usr/lib and /usr/bin directories, respectively. To install libraries and binaries in custom directory, you can specify the directory by passing --prefix flag. For example: ./configure --prefix=$(pwd)/install

   Alternatively, you can also run the below script, passing the required compiler as an argument:

   ./build_script.sh

   For, ARM based targets:

   ./build_script.sh --host=aarch64-linux-gnu

   By default, it will compile for X86 target.

Code Organization

• qcci: Provides functions that QMI clients can use to send and receive QMI messages.
• qcsi: Provides functions that QMI servers can use to send and receive QMI messages.
• qencdec: Provides functions to encode/decode QMI messages in TLV format.
• common: Provides common request and response messages that any QMI client can use.
• tests: Sample QMI client and service implementations.
• include: Contains headers to be included by QMI clients.

License

qmi-framework is licensed under the BSD 3-clause "New" or "Revised" License.