SPINLOCK

Table of Contents

• Features Supported
• SysConfig Features
• Features NOT Supported
• Important Usage Guidelines
• Example Usage
• API

The Spinlock driver provides API to program the Spinlock module to synchronize processes running on multiple processors in the device.

Features Supported

• 256 spinlocks
• Lock and unlock API

SysConfig Features

Note

It is strongly recommend to use SysConfig where it is available instead of using direct SW API calls. This will help simplify the SW application and also catch common mistakes early in the development cycle.

• Not applicable/supported

Features NOT Supported

NA

Important Usage Guidelines

• The Spinlock driver doesn't enforce below limitation as defined in device manual. It is the responsibility of the application to take care of below recommendations
• Spinlock is appropriate for mutual exclusion for access to a shared data structure. It should be used only when:
  • The time to hold the lock is predictable and small (for example, a maximum hold time of less than 200 CPU cycles may be acceptable).
  • The locking task cannot be preempted, suspended, or interrupted while holding the lock (this would make the hold time large and unpredictable).
  • The lock is lightly contended, that is the chance of any other process (or processor) trying to acquire the lock while it is held is small.

Example Usage

Include the below file to access the APIs

#include <drivers/spinlock.h>

Lock API

    int32_t  status;
 
    /* Spin till lock is acquired */
    while(1U)
    {
        status = Spinlock_lock(spinlockBaseAddr, lockNum);
        if(status == SPINLOCK_LOCK_STATUS_FREE)
        {
            break;  /* Free and taken */
        }
    }
 
    /*
     * enter critical section
     */

Unlock API

    Spinlock_unlock(spinlockBaseAddr, lockNum);

API

APIs for SPINLOCK