Allwinner R128 SDK HAL Module Development Guide HW Spinlock

aleksib

Allwinner R128 SDK HAL Module Development Guide HW Spinlock [Copy link]

 

# HW Spinlock ## Module Introduction hwspinlock provides a hardware synchronization mechanism. The lock operation can prevent multiple processors from processing shared data at the same time. Ensure data consistency. ## Source code structure``` ├── hal_hwspinlock.c ├── hwspinlock.h ├── Kconfig ├── Makefile ├── platform │ ├── hwspinlock-sun20iw2.h └── platform-hwspinlock.h ``` ## Module configuration The configuration path is as follows: ``` There is no help available for this option. Symbol: DRIVERS_HWSPINLOCK [=y] Type : boolean Prompt: enable hwspinlock driver Location: -> Drivers options -> Supported drivers -> HW SPINLOCK Devices ``` ## Module interface description Header file: ```c #include<hal_hwspinlock.h> ``` ### Get lock function prototype``` int hal_hwspinlock_get(int num) ``` Parameters: - `num`: `0~31`, the sequence number of hwspinlock lock Return value: - `HWSPINLOCK_OK`: Lock completed - `HWSPINLOCK_EXCEED_MAX`: The lock has reached the maximum value and failed to obtain - `HWSPINLOCK_ERR`: Lock failed### Unlock function prototype``` int hal_hwspinlock_put(int num) ``` Parameters: - `num`: `0~31`, the sequence number of hwspinlock lock Return value: - `HWSPINLOCK_OK`: Lock completed - `HWSPINLOCK_EXCEED_MAX`: The lock has reached the maximum value and failed to obtain### Check whether the lock is in use Function prototype``` int hal_hwspinlock_check_taken(int num) ``` Parameters: - `num`: `0~31`, the serial number of hwspinlock lock Return value - 1: in use - 0: not in use ## Module usage example ```c #include<stdio.h> #include <stdlib.h> #include<stdint.h> #include<string.h> #include<unistd.h> #include<hal_log.h> #include<hal_cmd.h> #include<hal_hwspinlock.h> static int cmd_test_hwspinlock_get(int argc, char **argv) { hal_hwspinlock_get(0); return 0; } static int cmd_test_hwspinlock_put(int argc, char **argv) { hal_hwspinlock_put(0); return 0; } FINSH_FUNCTION_EXPORT_CMD(cmd_test_hwspinlock_get, hal_hwspinlock_get, test_hwspinlock) FINSH_FUNCTION_EXPORT_CMD(cmd_test_hwspinlock_put, hal_hwspinlock_put, test_hwspinlock) ``` In the FreeRTOS console, entering the `hal_hwspinlock_get` command will lock the device, and entering the `hal_hwspinlock_put` command will unlock it. </hal_hwspinlock.h></hal_cmd.h></hal_log.h></unistd.h></string.h></stdint.h></stdlib.h></stdio.h></hal_hwspinlock.h>

LitchiCheng

Theoretically, it is possible to write a deadlock using this hardware lock.