dp_lib (CSM Data Path Driver Library)

Overview

This repository contains a library component (dp_lib) for the csm_dp driver. It provides core functionalities, API definitions, and architectural specifics for the CSM data path.

Block Diagram

+---------------------+       +-----------------+
|     User Space      |       |    User Space   |
|                     |       |                 |
| dp_ping/L2/MAC-e    +-----> |   dp_lib API    |
|                     |       |                 |
+---------------------+       +--------|--------+
                                       |
                           (Interacts via ioctl/mmap)
                                       |
                                       V
                       +-----------------------------+
                       |        Kernel Space         |
                       |                             |
                       |      qcom_csm_dp Driver     |
                       |                             |
                       +--------------|--------------+
                                      | Manages:
                                      | - Character Device /dev/csmX-dpY
                                      | - Memory/Buffers
                                      | - Debugfs Interface
                                      |
                                      | Interacts with:
                                      | - MHI Host Driver
                                      V
                       +-----------------------------+
                       |        Kernel Space         |
                       |                             |
                       |       MHI Host Driver       |
                       |                             |
                       +--------------|--------------+
                                      | Interacts with
                                      V
                       +-----------------------------+
                       |          Hardware           |
                       |                             |
                       |       QDU100 Device         |
                       |                             |
                       +-----------------------------+

Build and Install

Navigate to the dp-lib top directory:

$ cd <Work Space>/dp-lib
$ make
$ sudo make install
$ sudo ldconfig

# Optional build command
$ cd <Work Space>/dp-lib/test/dp_ping/
$ make
$ sudo make install

dp_ping utility Usage

The dp_ping utility is a testing application that uses the dp_lib to send and receive packets, measure latency, and report statistics.

Usage:

dp_ping <option>

Options:

TX Options:

• -b <number>: Number of packets in one burst (1..64), default 1.
• -c <packet counter>: Packet counter, default infinite.
• -i <TX interval in us>: TX interval in microseconds (fractional values >=0 allowed), default 1,000,000 (1 second).
• -l <TX packet length in bytes>: TX packet length in bytes, default 1K, max ~2MB.
• -m: Enable TX packet mirroring.
• -C: Enable TX packet data capture.
• -G: Send packet in scatter-gather mode.
• --buf_size <size>: TX memory pool buffer size, default 2K bytes.
• --buf_count <count>: TX memory pool buffer count, default 4096 buffers.
• --tx_affinity <core_num>: Enable CPU affinity (1..number of available cores) for Tx thread.

RX Options:

• -t <timeout in ms>: Timeout in milliseconds, default 2,000.
• --rx_poll_interval <interval in us>: Rx poll interval in microseconds, relevant only with -P (polling mode), default 125.
• --rx_affinity <core_num>: Enable CPU affinity (1..number of available cores) for Rx thread.

REPORT Options:

• -d <max pending result>: Maximum pending result for the internal result FIFO.
• -p <period in seconds>: Report period in seconds, default 10.
• -r <interval to report in ms>: Interval to report in milliseconds.
• -s: Use syslog for logging (instead of printf).
• -S: Report TX status statistics.

General Options:

• -v: Enable verbose logging.
• -x: Enable checksum verification.
• -B <bus number>: Bus number, default 0. Used to specify the bus number for the DP device (e.g., /dev/csm<bus_num>-dp<vf_num>).
• -D: Obsolete, see -V.
• -L: Print latency statistics for this report period.
• -P: Polling mode (Tx/Rx over DATA channel).
• -R: Fill packet payload from random number generator.
• -V <VF number>: Virtual function (VF0..3), default 0. Used to specify the virtual function number for the DP device (e.g., /dev/csm<bus_num>-dp<vf_num>).

Example Commands:

• Basic Ping (Control Channel):

  dp_ping -l 1024 -c 100 -i 1000000

  Sends 100 packets of 1KB length with 1 second interval on the control channel.

• Data Channel Polling Mode with Latency Stats:

  dp_ping -P -l 2048 -c 5000 -i 500 -L

  Sends 5000 packets of 2KB length every 500 microseconds on the data channel in polling mode, and reports latency statistics.

• With TX Affinity and Verification:

  dp_ping -l 512 -x --tx_affinity 2

  Sends packets of 512 bytes with checksum verification, ensuring the TX thread runs on CPU core 2.

• Traffic Capture to File:

  dp_ping -C -l 1024 -c 1000

  Sends 1000 packets and captures the traffic to /tmp/dp_ping.pcap_VF<vf_num>.

• Specifying Bus and VF Numbers:

  dp_ping -B 1 -V 2 -l 1024 -c 10

  Initializes dp_ping to interact with the device /dev/csm1-dp2, sending 10 packets of 1KB length.

For specific integration and usage, refer to the main csm_dp driver documentation and source code, as well as any platform-specific documentation (e.g., for QDU100).

License

Licensed under BSD-3-Clause-Clear