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/*
ChibiOS - Copyright (C) 2006..2015 Giovanni Di Sirio.
This file is part of ChibiOS.
ChibiOS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file chschd.h
* @brief Scheduler macros and structures.
*
* @addtogroup scheduler
* @{
*/
#ifndef _CHSCHD_H_
#define _CHSCHD_H_
/*===========================================================================*/
/* Module constants. */
/*===========================================================================*/
/**
* @name Wakeup status codes
* @{
*/
#define MSG_OK (msg_t)0 /**< @brief Normal wakeup message. */
#define MSG_TIMEOUT (msg_t)-1 /**< @brief Wakeup caused by a timeout
condition. */
#define MSG_RESET (msg_t)-2 /**< @brief Wakeup caused by a reset
condition. */
/** @} */
/**
* @name Priority constants
* @{
*/
#define NOPRIO (tprio_t)0 /**< @brief Ready list header
priority. */
#define IDLEPRIO (tprio_t)1 /**< @brief Idle priority. */
#define LOWPRIO (tprio_t)2 /**< @brief Lowest priority. */
#define NORMALPRIO (tprio_t)64 /**< @brief Normal priority. */
#define HIGHPRIO (tprio_t)127 /**< @brief Highest priority. */
#define ABSPRIO (tprio_t)255 /**< @brief Greatest priority. */
/** @} */
/**
* @name Thread states
* @{
*/
#define CH_STATE_READY (tstate_t)0 /**< @brief Waiting on the
ready list. */
#define CH_STATE_CURRENT (tstate_t)1 /**< @brief Currently running. */
#define CH_STATE_WTSTART (tstate_t)2 /**< @brief Just created. */
#define CH_STATE_SUSPENDED (tstate_t)3 /**< @brief Suspended state. */
#define CH_STATE_QUEUED (tstate_t)4 /**< @brief On an I/O queue. */
#define CH_STATE_WTSEM (tstate_t)5 /**< @brief On a semaphore. */
#define CH_STATE_WTMTX (tstate_t)6 /**< @brief On a mutex. */
#define CH_STATE_WTCOND (tstate_t)7 /**< @brief On a cond.variable.*/
#define CH_STATE_SLEEPING (tstate_t)8 /**< @brief Sleeping. */
#define CH_STATE_WTEXIT (tstate_t)9 /**< @brief Waiting a thread. */
#define CH_STATE_WTOREVT (tstate_t)10 /**< @brief One event. */
#define CH_STATE_WTANDEVT (tstate_t)11 /**< @brief Several events. */
#define CH_STATE_SNDMSGQ (tstate_t)12 /**< @brief Sending a message,
in queue. */
#define CH_STATE_SNDMSG (tstate_t)13 /**< @brief Sent a message,
waiting answer. */
#define CH_STATE_WTMSG (tstate_t)14 /**< @brief Waiting for a
message. */
#define CH_STATE_FINAL (tstate_t)15 /**< @brief Thread terminated. */
/**
* @brief Thread states as array of strings.
* @details Each element in an array initialized with this macro can be
* indexed using the numeric thread state values.
*/
#define CH_STATE_NAMES \
"READY", "CURRENT", "WTSTART", "SUSPENDED", "QUEUED", "WTSEM", "WTMTX", \
"WTCOND", "SLEEPING", "WTEXIT", "WTOREVT", "WTANDEVT", "SNDMSGQ", \
"SNDMSG", "WTMSG", "FINAL"
/** @} */
/**
* @name Thread flags and attributes
* @{
*/
#define CH_FLAG_MODE_MASK (tmode_t)3U /**< @brief Thread memory mode
mask. */
#define CH_FLAG_MODE_STATIC (tmode_t)0U /**< @brief Static thread. */
#define CH_FLAG_MODE_HEAP (tmode_t)1U /**< @brief Thread allocated
from a Memory Heap. */
#define CH_FLAG_MODE_MPOOL (tmode_t)2U /**< @brief Thread allocated
from a Memory Pool. */
#define CH_FLAG_TERMINATE (tmode_t)4U /**< @brief Termination requested
flag. */
/** @} */
/**
* @name Working Areas and Alignment
*/
/**
* @brief Enforces a correct alignment for a stack area size value.
*
* @param[in] n the stack size to be aligned to the next stack
* alignment boundary
* @return The aligned stack size.
*
* @api
*/
#define THD_ALIGN_STACK_SIZE(n) \
(((((size_t)(n)) - 1U) | (sizeof(stkalign_t) - 1U)) + 1U)
/**
* @brief Calculates the total Working Area size.
*
* @param[in] n the stack size to be assigned to the thread
* @return The total used memory in bytes.
*
* @api
*/
#define THD_WORKING_AREA_SIZE(n) \
THD_ALIGN_STACK_SIZE(sizeof(thread_t) + PORT_WA_SIZE(n))
/**
* @brief Static working area allocation.
* @details This macro is used to allocate a static thread working area
* aligned as both position and size.
*
* @param[in] s the name to be assigned to the stack array
* @param[in] n the stack size to be assigned to the thread
*
* @api
*/
#define THD_WORKING_AREA(s, n) \
stkalign_t s[THD_WORKING_AREA_SIZE(n) / sizeof(stkalign_t)]
/** @} */
/**
* @name Threads abstraction macros
*/
/**
* @brief Thread declaration macro.
* @note Thread declarations should be performed using this macro because
* the port layer could define optimizations for thread functions.
*/
#define THD_FUNCTION(tname, arg) PORT_THD_FUNCTION(tname, arg)
/** @} */
/*===========================================================================*/
/* Module pre-compile time settings. */
/*===========================================================================*/
/*===========================================================================*/
/* Derived constants and error checks. */
/*===========================================================================*/
/*===========================================================================*/
/* Module data structures and types. */
/*===========================================================================*/
/**
* @brief Generic threads single link list, it works like a stack.
*/
struct ch_threads_list {
thread_t *p_next; /**< @brief Next in the list/queue. */
};
/**
* @brief Generic threads bidirectional linked list header and element.
*/
struct ch_threads_queue {
thread_t *p_next; /**< @brief Next in the list/queue. */
thread_t *p_prev; /**< @brief Previous in the queue. */
};
/**
* @brief Structure representing a thread.
* @note Not all the listed fields are always needed, by switching off some
* not needed ChibiOS/RT subsystems it is possible to save RAM space
* by shrinking this structure.
*/
struct ch_thread {
thread_t *p_next; /**< @brief Next in the list/queue. */
/* End of the fields shared with the threads_list_t structure.*/
thread_t *p_prev; /**< @brief Previous in the queue. */
/* End of the fields shared with the threads_queue_t structure.*/
tprio_t p_prio; /**< @brief Thread priority. */
struct context p_ctx; /**< @brief Processor context. */
#if (CH_CFG_USE_REGISTRY == TRUE) || defined(__DOXYGEN__)
thread_t *p_newer; /**< @brief Newer registry element. */
thread_t *p_older; /**< @brief Older registry element. */
#endif
/* End of the fields shared with the ReadyList structure. */
#if (CH_CFG_USE_REGISTRY == TRUE) || defined(__DOXYGEN__)
/**
* @brief Thread name or @p NULL.
*/
const char *p_name;
#endif
#if (CH_DBG_ENABLE_STACK_CHECK == TRUE) || defined(__DOXYGEN__)
/**
* @brief Thread stack boundary.
*/
stkalign_t *p_stklimit;
#endif
/**
* @brief Current thread state.
*/
tstate_t p_state;
/**
* @brief Various thread flags.
*/
tmode_t p_flags;
#if (CH_CFG_USE_DYNAMIC == TRUE) || defined(__DOXYGEN__)
/**
* @brief References to this thread.
*/
trefs_t p_refs;
#endif
/**
* @brief Number of ticks remaining to this thread.
*/
#if (CH_CFG_TIME_QUANTUM > 0) || defined(__DOXYGEN__)
tslices_t p_preempt;
#endif
#if (CH_DBG_THREADS_PROFILING == TRUE) || defined(__DOXYGEN__)
/**
* @brief Thread consumed time in ticks.
* @note This field can overflow.
*/
volatile systime_t p_time;
#endif
/**
* @brief State-specific fields.
* @note All the fields declared in this union are only valid in the
* specified state or condition and are thus volatile.
*/
union {
/**
* @brief Thread wakeup code.
* @note This field contains the low level message sent to the thread
* by the waking thread or interrupt handler. The value is valid
* after exiting the @p chSchWakeupS() function.
*/
msg_t rdymsg;
/**
* @brief Thread exit code.
* @note The thread termination code is stored in this field in order
* to be retrieved by the thread performing a @p chThdWait() on
* this thread.
*/
msg_t exitcode;
/**
* @brief Pointer to a generic "wait" object.
* @note This field is used to get a generic pointer to a synchronization
* object and is valid when the thread is in one of the wait
* states.
*/
void *wtobjp;
/**
* @brief Pointer to a generic thread reference object.
* @note This field is used to get a pointer to a synchronization
* object and is valid when the thread is in @p CH_STATE_SUSPENDED
* state.
*/
thread_reference_t *wttrp;
#if (CH_CFG_USE_MESSAGES == TRUE) || defined(__DOXYGEN__)
/**
* @brief Thread sent message.
*/
msg_t sentmsg;
#endif
#if (CH_CFG_USE_SEMAPHORES == TRUE) || defined(__DOXYGEN__)
/**
* @brief Pointer to a generic semaphore object.
* @note This field is used to get a pointer to a synchronization
* object and is valid when the thread is in @p CH_STATE_WTSEM
* state.
*/
struct ch_semaphore *wtsemp;
#endif
#if (CH_CFG_USE_MUTEXES == TRUE) || defined(__DOXYGEN__)
/**
* @brief Pointer to a generic mutex object.
* @note This field is used to get a pointer to a synchronization
* object and is valid when the thread is in @p CH_STATE_WTMTX
* state.
*/
struct ch_mutex *wtmtxp;
#endif
#if (CH_CFG_USE_EVENTS == TRUE) || defined(__DOXYGEN__)
/**
* @brief Enabled events mask.
* @note This field is only valid while the thread is in the
* @p CH_STATE_WTOREVT or @p CH_STATE_WTANDEVT states.
*/
eventmask_t ewmask;
#endif
} p_u;
#if (CH_CFG_USE_WAITEXIT == TRUE) || defined(__DOXYGEN__)
/**
* @brief Termination waiting list.
*/
threads_list_t p_waiting;
#endif
#if (CH_CFG_USE_MESSAGES == TRUE) || defined(__DOXYGEN__)
/**
* @brief Messages queue.
*/
threads_queue_t p_msgqueue;
#endif
#if (CH_CFG_USE_EVENTS == TRUE) || defined(__DOXYGEN__)
/**
* @brief Pending events mask.
*/
eventmask_t p_epending;
#endif
#if (CH_CFG_USE_MUTEXES == TRUE) || defined(__DOXYGEN__)
/**
* @brief List of the mutexes owned by this thread.
* @note The list is terminated by a @p NULL in this field.
*/
struct ch_mutex *p_mtxlist;
/**
* @brief Thread's own, non-inherited, priority.
*/
tprio_t p_realprio;
#endif
#if ((CH_CFG_USE_DYNAMIC == TRUE) && (CH_CFG_USE_MEMPOOLS == TRUE)) || \
defined(__DOXYGEN__)
/**
* @brief Memory Pool where the thread workspace is returned.
*/
void *p_mpool;
#endif
#if (CH_DBG_STATISTICS == TRUE) || defined(__DOXYGEN__)
/**
* @brief Thread statistics.
*/
time_measurement_t p_stats;
#endif
#if defined(CH_CFG_THREAD_EXTRA_FIELDS)
/* Extra fields defined in chconf.h.*/
CH_CFG_THREAD_EXTRA_FIELDS
#endif
};
/**
* @extends virtual_timers_list_t
*
* @brief Virtual Timer descriptor structure.
*/
struct ch_virtual_timer {
virtual_timer_t *vt_next; /**< @brief Next timer in the list. */
virtual_timer_t *vt_prev; /**< @brief Previous timer in the list. */
systime_t vt_delta; /**< @brief Time delta before timeout. */
vtfunc_t vt_func; /**< @brief Timer callback function
pointer. */
void *vt_par; /**< @brief Timer callback function
parameter. */
};
/**
* @brief Virtual timers list header.
* @note The timers list is implemented as a double link bidirectional list
* in order to make the unlink time constant, the reset of a virtual
* timer is often used in the code.
*/
struct ch_virtual_timers_list {
virtual_timer_t *vt_next; /**< @brief Next timer in the delta
list. */
virtual_timer_t *vt_prev; /**< @brief Last timer in the delta
list. */
systime_t vt_delta; /**< @brief Must be initialized to -1. */
#if (CH_CFG_ST_TIMEDELTA == 0) || defined(__DOXYGEN__)
volatile systime_t vt_systime; /**< @brief System Time counter. */
#endif
#if (CH_CFG_ST_TIMEDELTA > 0) || defined(__DOXYGEN__)
/**
* @brief System time of the last tick event.
*/
systime_t vt_lasttime;/**< @brief System time of the last
tick event. */
#endif
};
/**
* @extends threads_queue_t
*/
struct ch_ready_list {
threads_queue_t r_queue; /**< @brief Threads queue. */
tprio_t r_prio; /**< @brief This field must be
initialized to zero. */
struct context r_ctx; /**< @brief Not used, present because
offsets. */
#if (CH_CFG_USE_REGISTRY == TRUE) || defined(__DOXYGEN__)
thread_t *r_newer; /**< @brief Newer registry element. */
thread_t *r_older; /**< @brief Older registry element. */
#endif
/* End of the fields shared with the thread_t structure.*/
thread_t *r_current; /**< @brief The currently running
thread. */
};
/**
* @brief System debug data structure.
*/
struct ch_system_debug {
/**
* @brief Pointer to the panic message.
* @details This pointer is meant to be accessed through the debugger, it is
* written once and then the system is halted.
* @note Accesses to this pointer must never be optimized out so the
* field itself is declared volatile.
*/
const char * volatile panic_msg;
#if (CH_DBG_SYSTEM_STATE_CHECK == TRUE) || defined(__DOXYGEN__)
/**
* @brief ISR nesting level.
*/
cnt_t isr_cnt;
/**
* @brief Lock nesting level.
*/
cnt_t lock_cnt;
#endif
#if (CH_DBG_ENABLE_TRACE == TRUE) || defined(__DOXYGEN__)
/**
* @brief Public trace buffer.
*/
ch_trace_buffer_t trace_buffer;
#endif
};
/**
* @brief System data structure.
* @note This structure contain all the data areas used by the OS except
* stacks.
*/
struct ch_system {
/**
* @brief Ready list header.
*/
ready_list_t rlist;
/**
* @brief Virtual timers delta list header.
*/
virtual_timers_list_t vtlist;
/**
* @brief System debug.
*/
system_debug_t dbg;
/**
* @brief Main thread descriptor.
*/
thread_t mainthread;
#if (CH_CFG_USE_TM == TRUE) || defined(__DOXYGEN__)
/**
* @brief Time measurement calibration data.
*/
tm_calibration_t tm;
#endif
#if (CH_DBG_STATISTICS == TRUE) || defined(__DOXYGEN__)
/**
* @brief Global kernel statistics.
*/
kernel_stats_t kernel_stats;
#endif
#if (CH_CFG_NO_IDLE_THREAD == FALSE) || defined(__DOXYGEN__)
/**
* @brief Idle thread working area.
*/
THD_WORKING_AREA(idle_thread_wa, PORT_IDLE_THREAD_STACK_SIZE);
#endif
};
/*===========================================================================*/
/* Module macros. */
/*===========================================================================*/
/**
* @brief Returns the priority of the first thread on the given ready list.
*
* @notapi
*/
#define firstprio(rlp) ((rlp)->p_next->p_prio)
/**
* @brief Current thread pointer access macro.
* @note This macro is not meant to be used in the application code but
* only from within the kernel, use the @p chThdSelf() API instead.
* @note It is forbidden to use this macro in order to change the pointer
* (currp = something), use @p setcurrp() instead.
*/
#define currp ch.rlist.r_current
/**
* @brief Current thread pointer change macro.
* @note This macro is not meant to be used in the application code but
* only from within the kernel.
*
* @notapi
*/
#define setcurrp(tp) (currp = (tp))
/*===========================================================================*/
/* External declarations. */
/*===========================================================================*/
#if !defined(__DOXYGEN__)
extern ch_system_t ch;
#endif
/*
* Scheduler APIs.
*/
#ifdef __cplusplus
extern "C" {
#endif
void _scheduler_init(void);
thread_t *chSchReadyI(thread_t *tp);
void chSchGoSleepS(tstate_t newstate);
msg_t chSchGoSleepTimeoutS(tstate_t newstate, systime_t time);
void chSchWakeupS(thread_t *ntp, msg_t msg);
void chSchRescheduleS(void);
bool chSchIsPreemptionRequired(void);
void chSchDoRescheduleBehind(void);
void chSchDoRescheduleAhead(void);
void chSchDoReschedule(void);
#if CH_CFG_OPTIMIZE_SPEED == FALSE
void queue_prio_insert(thread_t *tp, threads_queue_t *tqp);
void queue_insert(thread_t *tp, threads_queue_t *tqp);
thread_t *queue_fifo_remove(threads_queue_t *tqp);
thread_t *queue_lifo_remove(threads_queue_t *tqp);
thread_t *queue_dequeue(thread_t *tp);
void list_insert(thread_t *tp, threads_list_t *tlp);
thread_t *list_remove(threads_list_t *tlp);
#endif /* CH_CFG_OPTIMIZE_SPEED == FALSE */
#ifdef __cplusplus
}
#endif
/*===========================================================================*/
/* Module inline functions. */
/*===========================================================================*/
/**
* @brief Threads list initialization.
*
* @param[in] tlp pointer to the threads list object
*
* @notapi
*/
static inline void list_init(threads_list_t *tlp) {
tlp->p_next = (thread_t *)tlp;
}
/**
* @brief Evaluates to @p true if the specified threads list is empty.
*
* @param[in] tlp pointer to the threads list object
* @return The status of the list.
*
* @notapi
*/
static inline bool list_isempty(threads_list_t *tlp) {
return (bool)(tlp->p_next == (thread_t *)tlp);
}
/**
* @brief Evaluates to @p true if the specified threads list is not empty.
*
* @param[in] tlp pointer to the threads list object
* @return The status of the list.
*
* @notapi
*/
static inline bool list_notempty(threads_list_t *tlp) {
return (bool)(tlp->p_next != (thread_t *)tlp);
}
/**
* @brief Threads queue initialization.
*
* @param[in] tqp pointer to the threads queue object
*
* @notapi
*/
static inline void queue_init(threads_queue_t *tqp) {
tqp->p_next = (thread_t *)tqp;
tqp->p_prev = (thread_t *)tqp;
}
/**
* @brief Evaluates to @p true if the specified threads queue is empty.
*
* @param[in] tqp pointer to the threads queue object
* @return The status of the queue.
*
* @notapi
*/
static inline bool queue_isempty(const threads_queue_t *tqp) {
return (bool)(tqp->p_next == (const thread_t *)tqp);
}
/**
* @brief Evaluates to @p true if the specified threads queue is not empty.
*
* @param[in] tqp pointer to the threads queue object
* @return The status of the queue.
*
* @notapi
*/
static inline bool queue_notempty(const threads_queue_t *tqp) {
return (bool)(tqp->p_next != (const thread_t *)tqp);
}
/* If the performance code path has been chosen then all the following
functions are inlined into the various kernel modules.*/
#if CH_CFG_OPTIMIZE_SPEED == TRUE
static inline void list_insert(thread_t *tp, threads_list_t *tlp) {
tp->p_next = tlp->p_next;
tlp->p_next = tp;
}
static inline thread_t *list_remove(threads_list_t *tlp) {
thread_t *tp = tlp->p_next;
tlp->p_next = tp->p_next;
return tp;
}
static inline void queue_prio_insert(thread_t *tp, threads_queue_t *tqp) {
thread_t *cp = (thread_t *)tqp;
do {
cp = cp->p_next;
} while ((cp != (thread_t *)tqp) && (cp->p_prio >= tp->p_prio));
tp->p_next = cp;
tp->p_prev = cp->p_prev;
tp->p_prev->p_next = tp;
cp->p_prev = tp;
}
static inline void queue_insert(thread_t *tp, threads_queue_t *tqp) {
tp->p_next = (thread_t *)tqp;
tp->p_prev = tqp->p_prev;
tp->p_prev->p_next = tp;
tqp->p_prev = tp;
}
static inline thread_t *queue_fifo_remove(threads_queue_t *tqp) {
thread_t *tp = tqp->p_next;
tqp->p_next = tp->p_next;
tqp->p_next->p_prev = (thread_t *)tqp;
return tp;
}
static inline thread_t *queue_lifo_remove(threads_queue_t *tqp) {
thread_t *tp = tqp->p_prev;
tqp->p_prev = tp->p_prev;
tqp->p_prev->p_next = (thread_t *)tqp;
return tp;
}
static inline thread_t *queue_dequeue(thread_t *tp) {
tp->p_prev->p_next = tp->p_next;
tp->p_next->p_prev = tp->p_prev;
return tp;
}
#endif /* CH_CFG_OPTIMIZE_SPEED == TRUE */
/**
* @brief Determines if the current thread must reschedule.
* @details This function returns @p true if there is a ready thread with
* higher priority.
*
* @return The priorities situation.
* @retval false if rescheduling is not necessary.
* @retval true if there is a ready thread at higher priority.
*
* @iclass
*/
static inline bool chSchIsRescRequiredI(void) {
chDbgCheckClassI();
return firstprio(&ch.rlist.r_queue) > currp->p_prio;
}
/**
* @brief Determines if yielding is possible.
* @details This function returns @p true if there is a ready thread with
* equal or higher priority.
*
* @return The priorities situation.
* @retval false if yielding is not possible.
* @retval true if there is a ready thread at equal or higher priority.
*
* @sclass
*/
static inline bool chSchCanYieldS(void) {
chDbgCheckClassS();
return firstprio(&ch.rlist.r_queue) >= currp->p_prio;
}
/**
* @brief Yields the time slot.
* @details Yields the CPU control to the next thread in the ready list with
* equal or higher priority, if any.
*
* @sclass
*/
static inline void chSchDoYieldS(void) {
chDbgCheckClassS();
if (chSchCanYieldS()) {
chSchDoRescheduleBehind();
}
}
/**
* @brief Inline-able preemption code.
* @details This is the common preemption code, this function must be invoked
* exclusively from the port layer.
*
* @special
*/
static inline void chSchPreemption(void) {
tprio_t p1 = firstprio(&ch.rlist.r_queue);
tprio_t p2 = currp->p_prio;
#if CH_CFG_TIME_QUANTUM > 0
if (currp->p_preempt > (tslices_t)0) {
if (p1 > p2) {
chSchDoRescheduleAhead();
}
}
else {
if (p1 >= p2) {
chSchDoRescheduleBehind();
}
}
#else /* CH_CFG_TIME_QUANTUM == 0 */
if (p1 >= p2) {
chSchDoRescheduleAhead();
}
#endif /* CH_CFG_TIME_QUANTUM == 0 */
}
#endif /* _CHSCHD_H_ */
/** @} */
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