interface chip

Troubleshooting Memory Leaks in the CC2642R1FRGZR System

Troubleshooting Memory Leaks in the CC2642R1FRGZR System

Introduction

Memory leaks can be a serious issue in embedded systems, as they lead to inefficient memory usage and can eventually cause a system crash or unexpected behavior. The CC2642R1FRGZR is a Bluetooth Low Energy (BLE) SoC (System on Chip) from Texas Instruments, widely used in embedded systems. In this guide, we will analyze common causes of memory leaks in the CC2642R1FRGZR system and provide a step-by-step approach to resolve them.

1. Understanding the Issue: What Is a Memory Leak?

A memory leak occurs when a program allocates memory but fails to release it after it is no longer needed. Over time, this can accumulate, leading to a system running out of available memory, which can result in crashes, slow performance, or undefined behavior.

2. Identifying Memory Leaks in CC2642R1FRGZR

When working with embedded systems like the CC2642R1FRGZR, memory leaks can arise from the following areas:

Improper Dynamic Memory Allocation: Using malloc() or other dynamic memory allocation functions without corresponding free() calls. Static or Global Variable Mis Management : Memory allocated to global or static variables not properly deallocated. Resource Handling in Bluetooth Stack: In BLE systems, failing to release resources related to Bluetooth connections, advertisements, or services. Interrupts and Timers: Mismanagement of memory during interrupt handling or the use of timers, leading to memory allocations that are not freed. 3. Causes of Memory Leaks in the CC2642R1FRGZR System

The main causes of memory leaks in a CC2642R1FRGZR system include:

Faulty Memory Management Functions: Incorrect usage of memory allocation functions, such as forgetting to free allocated memory. Bluetooth Stack Mismanagement: Issues within the Bluetooth stack, like not deallocating resources after a BLE connection or advertisement. Excessive Interrupt-Driven Allocations: Frequent dynamic memory allocation within interrupt service routines (ISRs), leading to leaks when memory is not freed after the interrupt finishes. Timers Not Stopped Properly: Timers that allocate memory but do not release it when no longer needed. 4. Step-by-Step Troubleshooting Process

Follow these steps to troubleshoot and resolve memory leaks in the CC2642R1FRGZR system:

Step 1: Monitor System Memory Usage

Use the built-in memory tracking tools: Start by using SysConfig and TI-RTOS Memory Statistics (if applicable) to monitor the system’s memory usage over time. This will help identify if memory usage is increasing over time without being released. Track Heap Memory: Utilize the heap manager to monitor dynamic memory allocation in your application.

Step 2: Static Code Analysis

Examine Memory Allocation: Check your code for every instance where memory is dynamically allocated (malloc(), calloc(), etc.). Make sure there is a corresponding free() to release the memory. Code Review for Globals/Statics: Inspect global and static variables to ensure they are not unnecessarily holding onto memory.

Step 3: Check Bluetooth Stack Resource Management

BLE Connections and Advertisements: In BLE applications, ensure that resources related to connections, advertisements, and services are released when no longer needed. Correct Handling of BLE Events: When a BLE connection is terminated or an advertisement is stopped, confirm that memory allocated for these operations is freed properly.

Step 4: Inspect Interrupt Service Routines (ISRs)

Avoid Dynamic Allocation in ISRs: Ensure that dynamic memory allocation (e.g., malloc(), calloc()) is not done inside ISRs. Allocate memory only in the main application or in lower-priority tasks. Free Memory After Use: If memory is allocated in the ISR, make sure it is freed in the correct location after it is no longer needed.

Step 5: Timer Management

Stop Timers Properly: If your application uses timers, ensure that the timers are stopped and memory is freed once they are no longer needed. Timers should not hold memory allocations indefinitely.

Step 6: Use Memory Profiling Tools

Use TI’s Memory Debugging Tools: Texas Instruments provides tools like Memory Debugging Tool and Ubiquitous Leak Detection Tool to help detect memory leaks in embedded systems. These tools can be invaluable in identifying where memory is not being freed. Third-Party Tools: Consider using third-party tools such as Valgrind or Memory Sanitizers to detect memory allocation/deallocation issues in your firmware.

Step 7: Refactor and Optimize Code

Optimize Memory Usage: Refactor the code to optimize memory usage, particularly in resource-constrained environments like the CC2642R1FRGZR. Reduce Heap Usage: Minimize the use of the heap (dynamic memory), opting for statically allocated memory where possible. Free Memory When Done: Always free memory explicitly when you are done with it, especially in long-running processes or continuous loops. 5. Detailed Solution Example: Handling Bluetooth Stack Leaks

Let’s assume a Bluetooth Low Energy (BLE) application where a memory leak occurs after each BLE connection. Here is how you can fix it:

Identify the Issue: Use the memory profiling tool to see if memory usage increases every time a BLE connection is established.

Locate the Code: Identify the section of code where the BLE connection is created and check if any dynamic memory allocation happens during the connection setup.

Fix the Problem: Ensure that all allocated memory for services, characteristics, or connections is freed after the connection is terminated.

Example:

// Allocate memory for a BLE connection ble_connection_t* connection = malloc(sizeof(ble_connection_t)); // Connection established, use the connection // ... // Once connection is terminated, free memory free(connection); Test: After making these changes, test the system again using the memory profiling tool. The memory usage should no longer increase after each connection. 6. Conclusion

By following the above steps, you can effectively identify, troubleshoot, and resolve memory leaks in the CC2642R1FRGZR system. Proper memory management is crucial in embedded systems to ensure that resources are used efficiently and the system remains stable. Regular code review, the use of memory profiling tools, and careful management of dynamic memory allocations will help in preventing and resolving memory leaks.