/*************************************************************************** * Copyright (c) 2024 Microsoft Corporation * * This program and the accompanying materials are made available under the * terms of the MIT License which is available at * https://opensource.org/licenses/MIT. * * SPDX-License-Identifier: MIT **************************************************************************/ /**************************************************************************/ /**************************************************************************/ /** */ /** ThreadX Component */ /** */ /** Semaphore */ /** */ /**************************************************************************/ /**************************************************************************/ #define TX_SOURCE_CODE /* Include necessary system files. */ #include "tx_api.h" #include "tx_trace.h" #include "tx_thread.h" #include "tx_semaphore.h" /**************************************************************************/ /* */ /* FUNCTION RELEASE */ /* */ /* _tx_semaphore_get PORTABLE C */ /* 6.1 */ /* AUTHOR */ /* */ /* William E. Lamie, Microsoft Corporation */ /* */ /* DESCRIPTION */ /* */ /* This function gets an instance from the specified counting */ /* semaphore. */ /* */ /* INPUT */ /* */ /* semaphore_ptr Pointer to semaphore control block*/ /* wait_option Suspension option */ /* */ /* OUTPUT */ /* */ /* status Completion status */ /* */ /* CALLS */ /* */ /* _tx_thread_system_suspend Suspend thread service */ /* _tx_thread_system_ni_suspend Non-interruptable suspend thread */ /* */ /* CALLED BY */ /* */ /* Application Code */ /* */ /* RELEASE HISTORY */ /* */ /* DATE NAME DESCRIPTION */ /* */ /* 05-19-2020 William E. Lamie Initial Version 6.0 */ /* 09-30-2020 Yuxin Zhou Modified comment(s), */ /* resulting in version 6.1 */ /* */ /**************************************************************************/ UINT _tx_semaphore_get(TX_SEMAPHORE *semaphore_ptr, ULONG wait_option) { TX_INTERRUPT_SAVE_AREA TX_THREAD *thread_ptr; TX_THREAD *next_thread; TX_THREAD *previous_thread; UINT status; /* Default the status to TX_SUCCESS. */ status = TX_SUCCESS; /* Disable interrupts to get an instance from the semaphore. */ TX_DISABLE #ifdef TX_SEMAPHORE_ENABLE_PERFORMANCE_INFO /* Increment the total semaphore get counter. */ _tx_semaphore_performance_get_count++; /* Increment the number of attempts to get this semaphore. */ semaphore_ptr -> tx_semaphore_performance_get_count++; #endif /* If trace is enabled, insert this event into the trace buffer. */ TX_TRACE_IN_LINE_INSERT(TX_TRACE_SEMAPHORE_GET, semaphore_ptr, wait_option, semaphore_ptr -> tx_semaphore_count, TX_POINTER_TO_ULONG_CONVERT(&thread_ptr), TX_TRACE_SEMAPHORE_EVENTS) /* Log this kernel call. */ TX_EL_SEMAPHORE_GET_INSERT /* Determine if there is an instance of the semaphore. */ if (semaphore_ptr -> tx_semaphore_count != ((ULONG) 0)) { /* Decrement the semaphore count. */ semaphore_ptr -> tx_semaphore_count--; /* Restore interrupts. */ TX_RESTORE } /* Determine if the request specifies suspension. */ else if (wait_option != TX_NO_WAIT) { /* Determine if the preempt disable flag is non-zero. */ if (_tx_thread_preempt_disable != ((UINT) 0)) { /* Restore interrupts. */ TX_RESTORE /* Suspension is not allowed if the preempt disable flag is non-zero at this point - return error completion. */ status = TX_NO_INSTANCE; } else { /* Prepare for suspension of this thread. */ #ifdef TX_SEMAPHORE_ENABLE_PERFORMANCE_INFO /* Increment the total semaphore suspensions counter. */ _tx_semaphore_performance_suspension_count++; /* Increment the number of suspensions on this semaphore. */ semaphore_ptr -> tx_semaphore_performance_suspension_count++; #endif /* Pickup thread pointer. */ TX_THREAD_GET_CURRENT(thread_ptr) /* Setup cleanup routine pointer. */ thread_ptr -> tx_thread_suspend_cleanup = &(_tx_semaphore_cleanup); /* Setup cleanup information, i.e. this semaphore control block. */ thread_ptr -> tx_thread_suspend_control_block = (VOID *) semaphore_ptr; #ifndef TX_NOT_INTERRUPTABLE /* Increment the suspension sequence number, which is used to identify this suspension event. */ thread_ptr -> tx_thread_suspension_sequence++; #endif /* Setup suspension list. */ if (semaphore_ptr -> tx_semaphore_suspended_count == TX_NO_SUSPENSIONS) { /* No other threads are suspended. Setup the head pointer and just setup this threads pointers to itself. */ semaphore_ptr -> tx_semaphore_suspension_list = thread_ptr; thread_ptr -> tx_thread_suspended_next = thread_ptr; thread_ptr -> tx_thread_suspended_previous = thread_ptr; } else { /* This list is not NULL, add current thread to the end. */ next_thread = semaphore_ptr -> tx_semaphore_suspension_list; thread_ptr -> tx_thread_suspended_next = next_thread; previous_thread = next_thread -> tx_thread_suspended_previous; thread_ptr -> tx_thread_suspended_previous = previous_thread; previous_thread -> tx_thread_suspended_next = thread_ptr; next_thread -> tx_thread_suspended_previous = thread_ptr; } /* Increment the number of suspensions. */ semaphore_ptr -> tx_semaphore_suspended_count++; /* Set the state to suspended. */ thread_ptr -> tx_thread_state = TX_SEMAPHORE_SUSP; #ifdef TX_NOT_INTERRUPTABLE /* Call actual non-interruptable thread suspension routine. */ _tx_thread_system_ni_suspend(thread_ptr, wait_option); /* Restore interrupts. */ TX_RESTORE #else /* Set the suspending flag. */ thread_ptr -> tx_thread_suspending = TX_TRUE; /* Setup the timeout period. */ thread_ptr -> tx_thread_timer.tx_timer_internal_remaining_ticks = wait_option; /* Temporarily disable preemption. */ _tx_thread_preempt_disable++; /* Restore interrupts. */ TX_RESTORE /* Call actual thread suspension routine. */ _tx_thread_system_suspend(thread_ptr); #endif /* Return the completion status. */ status = thread_ptr -> tx_thread_suspend_status; } } else { /* Restore interrupts. */ TX_RESTORE /* Immediate return, return error completion. */ status = TX_NO_INSTANCE; } /* Return completion status. */ return(status); }