SPRADS6A March   2026  – March 2026 AM68A , AM69A , TDA4VM

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Data Movement within the TDA4VH
    1. 1.1 Common Bus Architecture Subsystem (CBASS)
    2. 1.2 Navigator Subsystems (NAVSS)
      1. 1.2.1 NAVSS North Bridge (NB)
    3. 1.3 Multicore Shared Memory Controller (MSMC)
  5. 2Quality of Service (QoS)
    1. 2.1 NAVSS0
      1. 2.1.1 NAVSS0 North Bridge
        1. 2.1.1.1 Normal vs Real-Time Traffic
    2. 2.2 Multicore Shared Memory Controller (MSMC)
    3. 2.3 DDR Subsystem (DDRSS)
      1. 2.3.1 MSMC2DDR Bridge
      2. 2.3.2 Class of Service (CoS)
    4. 2.4 QoS Summary
  6. 3Case Study: Display Sync Lost Issue
    1. 3.1 Problem Statement
    2. 3.2 Setup and Recreation
      1. 3.2.1 Requirements
        1. 3.2.1.1 RTOS Patches
          1. 3.2.1.1.1 0001-vision_apps-Remove-the-DSS-application-from-MCU2_0.patch
          2. 3.2.1.1.2 0002-vision_apps-Remove-display-use-from-the-AVP-demo.patch
        2. 3.2.1.2 Linux Patches
          1. 3.2.1.2.1 0001-arm64-dts-ti-k3-j784s4-vision-apps-Re-enable-DSS-for.patch
      2. 3.2.2 Host Setup
      3. 3.2.3 Target Setup
      4. 3.2.4 Recreation
    3. 3.3 Debugging QoS
      1. 3.3.1 CPTracer
        1. 3.3.1.1  Setup
        2. 3.3.1.2  Profiling Throughput
        3. 3.3.1.3  Profiling Latency
        4. 3.3.1.4  Profiling Transactions
        5. 3.3.1.5  Profiling Relevant Routes
        6. 3.3.1.6  Profiling DSS Throughput
          1. 3.3.1.6.1 Theoretical DSS Throughput
          2. 3.3.1.6.2 Normal DSS Throughput
          3. 3.3.1.6.3 DSS Throughput with the AVP Demo Running
        7. 3.3.1.7  Profiling DSS Latency
        8. 3.3.1.8  Profiling C7x Throughput
        9. 3.3.1.9  Profiling C7x Throughput vs DSS Latency
        10. 3.3.1.10 Profiling C7x_4 Core Transactions
      2. 3.3.2 Editing QoS Settings
        1. 3.3.2.1 Editing Order ID
          1. 3.3.2.1.1 DSS Order ID
          2. 3.3.2.1.2 C7x Order ID
        2. 3.3.2.2 NRT and RT Routing
          1. 3.3.2.2.1 NRT and RT Routing in U-Boot
        3. 3.3.2.3 Editing Priority
          1. 3.3.2.3.1 DSS Priority
          2. 3.3.2.3.2 C7x Priority
      3. 3.3.3 Editing CoS Mappings
        1. 3.3.3.1 CoS Mapping Registers
        2. 3.3.3.2 Checking CoS Mappings
    4. 3.4 Fixing the DSS Sync Losts
      1. 3.4.1 Remap C7x_4 Core Transactions
        1. 3.4.1.1 ti-u-boot-2023.04
        2. 3.4.1.2 ti-u-boot-2025.01
      2. 3.4.2 Honor All Priorities
        1. 3.4.2.1 ti-u-boot-2023.04
        2. 3.4.2.2 ti-u-boot-2025.01
  7. 4Summary
  8. 5References
  9. 6Revision History

2.3 DDR Subsystem (DDRSS)

The DDRSS contains quality of service mechanisms through the MSMC2DDR bridge while also containing it's own unique mechanism: class of service (CoS). The DDR controller utilizes its CoS mechanism to map VBUSM.C threads and priorities to its internal threads and priorities.