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tx_queue_receive.c
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tx_queue_receive.c
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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 */
/** */
/** Queue */
/** */
/**************************************************************************/
/**************************************************************************/
#define TX_SOURCE_CODE
/* Include necessary system files. */
#include "tx_api.h"
#include "tx_trace.h"
#include "tx_thread.h"
#include "tx_queue.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _tx_queue_receive PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function receives a message from the specified queue. If there */
/* are no messages in the queue, this function waits according to the */
/* option specified. */
/* */
/* INPUT */
/* */
/* queue_ptr Pointer to queue control block */
/* destination_ptr Pointer to message destination */
/* **** MUST BE LARGE ENOUGH TO */
/* HOLD MESSAGE **** */
/* wait_option Suspension option */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _tx_thread_system_resume Resume thread routine */
/* _tx_thread_system_ni_resume Non-interruptable resume thread */
/* _tx_thread_system_suspend Suspend thread routine */
/* _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_queue_receive(TX_QUEUE *queue_ptr, VOID *destination_ptr, ULONG wait_option)
{
TX_INTERRUPT_SAVE_AREA
TX_THREAD *thread_ptr;
ULONG *source;
ULONG *destination;
UINT size;
UINT suspended_count;
TX_THREAD *next_thread;
TX_THREAD *previous_thread;
UINT status;
/* Default the status to TX_SUCCESS. */
status = TX_SUCCESS;
/* Disable interrupts to receive message from queue. */
TX_DISABLE
#ifdef TX_QUEUE_ENABLE_PERFORMANCE_INFO
/* Increment the total messages received counter. */
_tx_queue_performance__messages_received_count++;
/* Increment the number of messages received from this queue. */
queue_ptr -> tx_queue_performance_messages_received_count++;
#endif
/* If trace is enabled, insert this event into the trace buffer. */
TX_TRACE_IN_LINE_INSERT(TX_TRACE_QUEUE_RECEIVE, queue_ptr, TX_POINTER_TO_ULONG_CONVERT(destination_ptr), wait_option, queue_ptr -> tx_queue_enqueued, TX_TRACE_QUEUE_EVENTS)
/* Log this kernel call. */
TX_EL_QUEUE_RECEIVE_INSERT
/* Pickup the thread suspension count. */
suspended_count = queue_ptr -> tx_queue_suspended_count;
/* Determine if there is anything in the queue. */
if (queue_ptr -> tx_queue_enqueued != TX_NO_MESSAGES)
{
/* Determine if there are any suspensions. */
if (suspended_count == TX_NO_SUSPENSIONS)
{
/* There is a message waiting in the queue and there are no suspensi. */
/* Setup source and destination pointers. */
source = queue_ptr -> tx_queue_read;
destination = TX_VOID_TO_ULONG_POINTER_CONVERT(destination_ptr);
size = queue_ptr -> tx_queue_message_size;
/* Copy message. Note that the source and destination pointers are
incremented by the macro. */
TX_QUEUE_MESSAGE_COPY(source, destination, size)
/* Determine if we are at the end. */
if (source == queue_ptr -> tx_queue_end)
{
/* Yes, wrap around to the beginning. */
source = queue_ptr -> tx_queue_start;
}
/* Setup the queue read pointer. */
queue_ptr -> tx_queue_read = source;
/* Increase the amount of available storage. */
queue_ptr -> tx_queue_available_storage++;
/* Decrease the enqueued count. */
queue_ptr -> tx_queue_enqueued--;
/* Restore interrupts. */
TX_RESTORE
}
else
{
/* At this point we know the queue is full. */
/* Pickup thread suspension list head pointer. */
thread_ptr = queue_ptr -> tx_queue_suspension_list;
/* Now determine if there is a queue front suspension active. */
/* Is the front suspension flag set? */
if (thread_ptr -> tx_thread_suspend_option == TX_TRUE)
{
/* Yes, a queue front suspension is present. */
/* Return the message associated with this suspension. */
/* Setup source and destination pointers. */
source = TX_VOID_TO_ULONG_POINTER_CONVERT(thread_ptr -> tx_thread_additional_suspend_info);
destination = TX_VOID_TO_ULONG_POINTER_CONVERT(destination_ptr);
size = queue_ptr -> tx_queue_message_size;
/* Copy message. Note that the source and destination pointers are
incremented by the macro. */
TX_QUEUE_MESSAGE_COPY(source, destination, size)
/* Message is now in the caller's destination. See if this is the only suspended thread
on the list. */
suspended_count--;
if (suspended_count == TX_NO_SUSPENSIONS)
{
/* Yes, the only suspended thread. */
/* Update the head pointer. */
queue_ptr -> tx_queue_suspension_list = TX_NULL;
}
else
{
/* At least one more thread is on the same expiration list. */
/* Update the list head pointer. */
next_thread = thread_ptr -> tx_thread_suspended_next;
queue_ptr -> tx_queue_suspension_list = next_thread;
/* Update the links of the adjacent threads. */
previous_thread = thread_ptr -> tx_thread_suspended_previous;
next_thread -> tx_thread_suspended_previous = previous_thread;
previous_thread -> tx_thread_suspended_next = next_thread;
}
/* Decrement the suspension count. */
queue_ptr -> tx_queue_suspended_count = suspended_count;
/* Prepare for resumption of the first thread. */
/* Clear cleanup routine to avoid timeout. */
thread_ptr -> tx_thread_suspend_cleanup = TX_NULL;
/* Put return status into the thread control block. */
thread_ptr -> tx_thread_suspend_status = TX_SUCCESS;
#ifdef TX_NOT_INTERRUPTABLE
/* Resume the thread! */
_tx_thread_system_ni_resume(thread_ptr);
/* Restore interrupts. */
TX_RESTORE
#else
/* Temporarily disable preemption. */
_tx_thread_preempt_disable++;
/* Restore interrupts. */
TX_RESTORE
/* Resume thread. */
_tx_thread_system_resume(thread_ptr);
#endif
}
else
{
/* At this point, we know that the queue is full and there
are one or more threads suspended trying to send another
message to this queue. */
/* Setup source and destination pointers. */
source = queue_ptr -> tx_queue_read;
destination = TX_VOID_TO_ULONG_POINTER_CONVERT(destination_ptr);
size = queue_ptr -> tx_queue_message_size;
/* Copy message. Note that the source and destination pointers are
incremented by the macro. */
TX_QUEUE_MESSAGE_COPY(source, destination, size)
/* Determine if we are at the end. */
if (source == queue_ptr -> tx_queue_end)
{
/* Yes, wrap around to the beginning. */
source = queue_ptr -> tx_queue_start;
}
/* Setup the queue read pointer. */
queue_ptr -> tx_queue_read = source;
/* Disable preemption. */
_tx_thread_preempt_disable++;
#ifdef TX_NOT_INTERRUPTABLE
/* Restore interrupts. */
TX_RESTORE
/* Interrupts are enabled briefly here to keep the interrupt
lockout time deterministic. */
/* Disable interrupts again. */
TX_DISABLE
#endif
/* Decrement the preemption disable variable. */
_tx_thread_preempt_disable--;
/* Setup source and destination pointers. */
source = TX_VOID_TO_ULONG_POINTER_CONVERT(thread_ptr -> tx_thread_additional_suspend_info);
destination = queue_ptr -> tx_queue_write;
size = queue_ptr -> tx_queue_message_size;
/* Copy message. Note that the source and destination pointers are
incremented by the macro. */
TX_QUEUE_MESSAGE_COPY(source, destination, size)
/* Determine if we are at the end. */
if (destination == queue_ptr -> tx_queue_end)
{
/* Yes, wrap around to the beginning. */
destination = queue_ptr -> tx_queue_start;
}
/* Adjust the write pointer. */
queue_ptr -> tx_queue_write = destination;
/* Pickup thread pointer. */
thread_ptr = queue_ptr -> tx_queue_suspension_list;
/* Message is now in the queue. See if this is the only suspended thread
on the list. */
suspended_count--;
if (suspended_count == TX_NO_SUSPENSIONS)
{
/* Yes, the only suspended thread. */
/* Update the head pointer. */
queue_ptr -> tx_queue_suspension_list = TX_NULL;
}
else
{
/* At least one more thread is on the same expiration list. */
/* Update the list head pointer. */
next_thread = thread_ptr -> tx_thread_suspended_next;
queue_ptr -> tx_queue_suspension_list = next_thread;
/* Update the links of the adjacent threads. */
previous_thread = thread_ptr -> tx_thread_suspended_previous;
next_thread -> tx_thread_suspended_previous = previous_thread;
previous_thread -> tx_thread_suspended_next = next_thread;
}
/* Decrement the suspension count. */
queue_ptr -> tx_queue_suspended_count = suspended_count;
/* Prepare for resumption of the first thread. */
/* Clear cleanup routine to avoid timeout. */
thread_ptr -> tx_thread_suspend_cleanup = TX_NULL;
/* Put return status into the thread control block. */
thread_ptr -> tx_thread_suspend_status = TX_SUCCESS;
#ifdef TX_NOT_INTERRUPTABLE
/* Resume the thread! */
_tx_thread_system_ni_resume(thread_ptr);
/* Restore interrupts. */
TX_RESTORE
#else
/* Temporarily disable preemption. */
_tx_thread_preempt_disable++;
/* Restore interrupts. */
TX_RESTORE
/* Resume thread. */
_tx_thread_system_resume(thread_ptr);
#endif
}
}
}
/* 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_QUEUE_EMPTY;
}
else
{
/* Prepare for suspension of this thread. */
#ifdef TX_QUEUE_ENABLE_PERFORMANCE_INFO
/* Increment the total queue empty suspensions counter. */
_tx_queue_performance_empty_suspension_count++;
/* Increment the number of empty suspensions on this queue. */
queue_ptr -> tx_queue_performance_empty_suspension_count++;
#endif
/* Pickup thread pointer. */
TX_THREAD_GET_CURRENT(thread_ptr)
/* Setup cleanup routine pointer. */
thread_ptr -> tx_thread_suspend_cleanup = &(_tx_queue_cleanup);
/* Setup cleanup information, i.e. this queue control
block and the source pointer. */
thread_ptr -> tx_thread_suspend_control_block = (VOID *) queue_ptr;
thread_ptr -> tx_thread_additional_suspend_info = (VOID *) destination_ptr;
thread_ptr -> tx_thread_suspend_option = TX_FALSE;
#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 (suspended_count == TX_NO_SUSPENSIONS)
{
/* No other threads are suspended. Setup the head pointer and
just setup this threads pointers to itself. */
queue_ptr -> tx_queue_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 = queue_ptr -> tx_queue_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 suspended thread count. */
queue_ptr -> tx_queue_suspended_count = suspended_count + ((UINT) 1);
/* Set the state to suspended. */
thread_ptr -> tx_thread_state = TX_QUEUE_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_QUEUE_EMPTY;
}
/* Return completion status. */
return(status);
}