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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** ThreadX Component */
/** */
/** Mutex */
/** */
/**************************************************************************/
/**************************************************************************/
#define TX_SOURCE_CODE
/* Include necessary system files. */
#include "tx_api.h"
#include "tx_trace.h"
#include "tx_thread.h"
#include "tx_mutex.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _tx_mutex_get PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function gets the specified mutex. If the calling thread */
/* already owns the mutex, an ownership count is simply increased. */
/* */
/* INPUT */
/* */
/* mutex_ptr Pointer to mutex 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 */
/* _tx_mutex_priority_change Inherit thread priority */
/* */
/* 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_mutex_get(TX_MUTEX *mutex_ptr, ULONG wait_option)
{
TX_INTERRUPT_SAVE_AREA
TX_THREAD *thread_ptr;
TX_MUTEX *next_mutex;
TX_MUTEX *previous_mutex;
TX_THREAD *mutex_owner;
TX_THREAD *next_thread;
TX_THREAD *previous_thread;
UINT status;
/* Disable interrupts to get an instance from the mutex. */
TX_DISABLE
#ifdef TX_MUTEX_ENABLE_PERFORMANCE_INFO
/* Increment the total mutex get counter. */
_tx_mutex_performance_get_count++;
/* Increment the number of attempts to get this mutex. */
mutex_ptr -> tx_mutex_performance_get_count++;
#endif
/* If trace is enabled, insert this event into the trace buffer. */
TX_TRACE_IN_LINE_INSERT(TX_TRACE_MUTEX_GET, mutex_ptr, wait_option, TX_POINTER_TO_ULONG_CONVERT(mutex_ptr -> tx_mutex_owner), mutex_ptr -> tx_mutex_ownership_count, TX_TRACE_MUTEX_EVENTS)
/* Log this kernel call. */
TX_EL_MUTEX_GET_INSERT
/* Pickup thread pointer. */
TX_THREAD_GET_CURRENT(thread_ptr)
/* Determine if this mutex is available. */
if (mutex_ptr -> tx_mutex_ownership_count == ((UINT) 0))
{
/* Set the ownership count to 1. */
mutex_ptr -> tx_mutex_ownership_count = ((UINT) 1);
/* Remember that the calling thread owns the mutex. */
mutex_ptr -> tx_mutex_owner = thread_ptr;
/* Determine if the thread pointer is valid. */
if (thread_ptr != TX_NULL)
{
/* Determine if priority inheritance is required. */
if (mutex_ptr -> tx_mutex_inherit == TX_TRUE)
{
/* Remember the current priority of thread. */
mutex_ptr -> tx_mutex_original_priority = thread_ptr -> tx_thread_priority;
/* Setup the highest priority waiting thread. */
mutex_ptr -> tx_mutex_highest_priority_waiting = ((UINT) TX_MAX_PRIORITIES);
}
/* Pickup next mutex pointer, which is the head of the list. */
next_mutex = thread_ptr -> tx_thread_owned_mutex_list;
/* Determine if this thread owns any other mutexes that have priority inheritance. */
if (next_mutex != TX_NULL)
{
/* Non-empty list. Link up the mutex. */
/* Pickup the next and previous mutex pointer. */
previous_mutex = next_mutex -> tx_mutex_owned_previous;
/* Place the owned mutex in the list. */
next_mutex -> tx_mutex_owned_previous = mutex_ptr;
previous_mutex -> tx_mutex_owned_next = mutex_ptr;
/* Setup this mutex's next and previous created links. */
mutex_ptr -> tx_mutex_owned_previous = previous_mutex;
mutex_ptr -> tx_mutex_owned_next = next_mutex;
}
else
{
/* The owned mutex list is empty. Add mutex to empty list. */
thread_ptr -> tx_thread_owned_mutex_list = mutex_ptr;
mutex_ptr -> tx_mutex_owned_next = mutex_ptr;
mutex_ptr -> tx_mutex_owned_previous = mutex_ptr;
}
/* Increment the number of mutexes owned counter. */
thread_ptr -> tx_thread_owned_mutex_count++;
}
/* Restore interrupts. */
TX_RESTORE
/* Return success. */
status = TX_SUCCESS;
}
/* Otherwise, see if the owning thread is trying to obtain the same mutex. */
else if (mutex_ptr -> tx_mutex_owner == thread_ptr)
{
/* The owning thread is requesting the mutex again, just
increment the ownership count. */
mutex_ptr -> tx_mutex_ownership_count++;
/* Restore interrupts. */
TX_RESTORE
/* Return success. */
status = TX_SUCCESS;
}
else
{
/* Determine if the request specifies suspension. */
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_NOT_AVAILABLE;
}
else
{
/* Prepare for suspension of this thread. */
/* Pickup the mutex owner. */
mutex_owner = mutex_ptr -> tx_mutex_owner;
#ifdef TX_MUTEX_ENABLE_PERFORMANCE_INFO
/* Increment the total mutex suspension counter. */
_tx_mutex_performance_suspension_count++;
/* Increment the number of suspensions on this mutex. */
mutex_ptr -> tx_mutex_performance_suspension_count++;
/* Determine if a priority inversion is present. */
if (thread_ptr -> tx_thread_priority < mutex_owner -> tx_thread_priority)
{
/* Yes, priority inversion is present! */
/* Increment the total mutex priority inversions counter. */
_tx_mutex_performance_priority_inversion_count++;
/* Increment the number of priority inversions on this mutex. */
mutex_ptr -> tx_mutex_performance_priority_inversion_count++;
#ifdef TX_THREAD_ENABLE_PERFORMANCE_INFO
/* Increment the number of total thread priority inversions. */
_tx_thread_performance_priority_inversion_count++;
/* Increment the number of priority inversions for this thread. */
thread_ptr -> tx_thread_performance_priority_inversion_count++;
#endif
}
#endif
/* Setup cleanup routine pointer. */
thread_ptr -> tx_thread_suspend_cleanup = &(_tx_mutex_cleanup);
/* Setup cleanup information, i.e. this mutex control
block. */
thread_ptr -> tx_thread_suspend_control_block = (VOID *) mutex_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 (mutex_ptr -> tx_mutex_suspended_count == TX_NO_SUSPENSIONS)
{
/* No other threads are suspended. Setup the head pointer and
just setup this threads pointers to itself. */
mutex_ptr -> tx_mutex_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 = mutex_ptr -> tx_mutex_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 suspension count. */
mutex_ptr -> tx_mutex_suspended_count++;
/* Set the state to suspended. */
thread_ptr -> tx_thread_state = TX_MUTEX_SUSP;
#ifdef TX_NOT_INTERRUPTABLE
/* Determine if we need to raise the priority of the thread
owning the mutex. */
if (mutex_ptr -> tx_mutex_inherit == TX_TRUE)
{
/* Determine if this is the highest priority to raise for this mutex. */
if (mutex_ptr -> tx_mutex_highest_priority_waiting > thread_ptr -> tx_thread_priority)
{
/* Remember this priority. */
mutex_ptr -> tx_mutex_highest_priority_waiting = thread_ptr -> tx_thread_priority;
}
/* Determine if we have to update inherit priority level of the mutex owner. */
if (thread_ptr -> tx_thread_priority < mutex_owner -> tx_thread_inherit_priority)
{
/* Remember the new priority inheritance priority. */
mutex_owner -> tx_thread_inherit_priority = thread_ptr -> tx_thread_priority;
}
/* Priority inheritance is requested, check to see if the thread that owns the mutex is lower priority. */
if (mutex_owner -> tx_thread_priority > thread_ptr -> tx_thread_priority)
{
/* Yes, raise the suspended, owning thread's priority to that
of the current thread. */
_tx_mutex_priority_change(mutex_owner, thread_ptr -> tx_thread_priority);
#ifdef TX_MUTEX_ENABLE_PERFORMANCE_INFO
/* Increment the total mutex priority inheritance counter. */
_tx_mutex_performance__priority_inheritance_count++;
/* Increment the number of priority inheritance situations on this mutex. */
mutex_ptr -> tx_mutex_performance__priority_inheritance_count++;
#endif
}
}
/* 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
/* Determine if we need to raise the priority of the thread
owning the mutex. */
if (mutex_ptr -> tx_mutex_inherit == TX_TRUE)
{
/* Determine if this is the highest priority to raise for this mutex. */
if (mutex_ptr -> tx_mutex_highest_priority_waiting > thread_ptr -> tx_thread_priority)
{
/* Remember this priority. */
mutex_ptr -> tx_mutex_highest_priority_waiting = thread_ptr -> tx_thread_priority;
}
/* Determine if we have to update inherit priority level of the mutex owner. */
if (thread_ptr -> tx_thread_priority < mutex_owner -> tx_thread_inherit_priority)
{
/* Remember the new priority inheritance priority. */
mutex_owner -> tx_thread_inherit_priority = thread_ptr -> tx_thread_priority;
}
/* Priority inheritance is requested, check to see if the thread that owns the mutex is lower priority. */
if (mutex_owner -> tx_thread_priority > thread_ptr -> tx_thread_priority)
{
/* Yes, raise the suspended, owning thread's priority to that
of the current thread. */
_tx_mutex_priority_change(mutex_owner, thread_ptr -> tx_thread_priority);
#ifdef TX_MUTEX_ENABLE_PERFORMANCE_INFO
/* Increment the total mutex priority inheritance counter. */
_tx_mutex_performance__priority_inheritance_count++;
/* Increment the number of priority inheritance situations on this mutex. */
mutex_ptr -> tx_mutex_performance__priority_inheritance_count++;
#endif
}
}
/* 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_NOT_AVAILABLE;
}
}
/* Return completion status. */
return(status);
}