/*
    ChibiOS - Copyright (C) 2006..2016 Giovanni Di Sirio

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

#ifndef MCUCONF_H
#define MCUCONF_H

/*
 * STM32L1xx drivers configuration.
 * The following settings override the default settings present in
 * the various device driver implementation headers.
 * Note that the settings for each driver only have effect if the whole
 * driver is enabled in halconf.h.
 *
 * IRQ priorities:
 * 15...0       Lowest...Highest.
 *
 * DMA priorities:
 * 0...3        Lowest...Highest.
 */

#define STM32L1xx_MCUCONF

/*
 * HAL driver system settings.
 */
#define STM32_NO_INIT                       FALSE
#define STM32_HSI_ENABLED                   TRUE
#define STM32_LSI_ENABLED                   TRUE
#define STM32_HSE_ENABLED                   FALSE
#define STM3
/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                 2011,2012,2013 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT 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/RT 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    chthreads.c
 * @brief   Threads code.
 *
 * @addtogroup threads
 * @details Threads related APIs and services.
 *
 *          <h2>Operation mode</h2>
 *          A thread is an abstraction of an independent instructions flow.
 *          In ChibiOS/RT a thread is represented by a "C" function owning
 *          a processor context, state informations and a dedicated stack
 *          area. In this scenario static variables are shared among all
 *          threads while automatic variables are local to the thread.<br>
 *          Operations defined for threads:
 *          - <b>Create</b>, a thread is started on the specified thread
 *            function. This operation is available in multiple variants,
 *            both static and dynamic.
 *          - <b>Exit</b>, a thread terminates by returning from its top
 *            level function or invoking a specific API, the thread can
 *            return a value that can be retrieved by other threads.
 *          - <b>Wait</b>, a thread waits for the termination of another
 *            thread and retrieves its return value.
 *          - <b>Resume</b>, a thread created in suspended state is started.
 *          - <b>Sleep</b>, the execution of a thread is suspended for the
 *            specified amount of time or the specified future absolute time
 *            is reached.
 *          - <b>SetPriority</b>, a thread changes its own priority level.
 *          - <b>Yield</b>, a thread voluntarily renounces to its time slot.
 *          .
 *          The threads subsystem is implicitly included in kernel however
 *          some of its part may be excluded by disabling them in @p chconf.h,
 *          see the @p CH_USE_WAITEXIT and @p CH_USE_DYNAMIC configuration
 *          options.
 * @{
 */

#include "ch.h"

/**
 * @brief   Initializes a thread structure.
 * @note    This is an internal functions, do not use it in application code.
 *
 * @param[in] tp        pointer to the thread
 * @param[in] prio      the priority level for the new thread
 * @return              The same thread pointer passed as parameter.
 *
 * @notapi
 */
Thread *_thread_init(Thread *tp, tprio_t prio) {

  tp->p_prio = prio;
  tp->p_state = THD_STATE_SUSPENDED;
  tp->p_flags = THD_MEM_MODE_STATIC;
#if CH_TIME_QUANTUM > 0
  tp->p_preempt = CH_TIME_QUANTUM;
#endif
#if CH_USE_MUTEXES
  tp->p_realprio = prio;
  tp->p_mtxlist = NULL;
#endif
#if CH_USE_EVENTS
  tp->p_epending = 0;
#endif
#if CH_DBG_THREADS_PROFILING
  tp->p_time = 0;
#endif
#if CH_USE_DYNAMIC
  tp->p_refs = 1;
#endif
#if CH_USE_REGISTRY
  tp->p_name = NULL;
  REG_INSERT(tp);
#endif
#if CH_USE_WAITEXIT
  list_init(&tp->p_waiting);
#endif
#if CH_USE_MESSAGES
  queue_init(&tp->p_msgqueue);
#endif
#if CH_DBG_ENABLE_STACK_CHECK
  tp->p_stklimit = (stkalign_t *)(tp + 1);
#endif
#if defined(THREAD_EXT_INIT_HOOK)
  THREAD_EXT_INIT_HOOK(tp);
#endif
  return tp;
}

#if CH_DBG_FILL_THREADS || defined(__DOXYGEN__)
/**
 * @brief   Memory fill utility.
 *
 * @param[in] startp    first address to fill
 * @param[in] endp      last address to fill +1
 * @param[in] v         filler value
 *
 * @notapi
 */
void _thread_memfill(uint8_t *startp, uint8_t *endp, uint8_t v) {

  while (startp < endp)
    *startp++ = v;
}
#endif /* CH_DBG_FILL_THREADS */

/**
 * @brief   Creates a new thread into a static memory area.
 * @details The new thread is initialized but not inserted in the ready list,
 *          the initial state is @p THD_STATE_SUSPENDED.
 * @post    The initialized thread can be subsequently started by invoking
 *          @p chThdResume(), @p chThdResumeI() or @p chSchWakeupS()
 *          depending on the execution context.
 * @note    A thread can terminate by calling @p chThdExit() or by simply
 *          returning from its main function.
 * @note    Threads created using this function do not obey to the
 *          @p CH_DBG_FILL_THREADS debug option because it would keep
 *          the kernel locked for too much time.
 *
 * @param[out] wsp      pointer to a working area dedicated to the thread stack
 * @param[in] size      size of the working area
 * @param[in] prio      the priority level for the new thread
 * @param[in] pf        the thread function
 * @param[in] arg       an argument passed to the thread function. It can be
 *                      @p NULL.
 * @return              The pointer to the @p Thread structure allocated for
 *                      the thread into the working space area.
 *
 * @iclass
 */
Thread *chThdCreateI(void *wsp, size_t size,
                     tprio_t prio, tfunc_t pf, void *arg) {
  /* Thread structure is layed out in the lower part of the thread workspace.*/
  Thread *tp = wsp;

  chDbgCheckClassI();

  chDbgCheck((wsp != NULL) && (size >= THD_WA_SIZE(0)) &&
             (prio <= HIGHPRIO) && (pf != NULL),
             "chThdCreateI");
  SETUP_CONTEXT(wsp, size, pf, arg);
  return _thread_init(tp, prio);
}

/**
 * @brief   Creates a new thread into a static memory area.
 * @note    A thread can terminate by calling @p chThdExit() or by simply
 *          returning from its main function.
 *
 * @param[out] wsp      pointer to a working area dedicated to the thread stack
 * @param[in] size      size of the working area
 * @param[in] prio      the priority level for the new thread
 * @param[in] pf        the thread function
 * @param[in] arg       an argument passed to the thread function. It can be
 *                      @p NULL.
 * @return              The pointer to the @p Thread structure allocated for
 *                      the thread into the working space area.
 *
 * @api
 */
Thread *chThdCreateStatic(void *wsp, size_t size,
                          tprio_t prio, tfunc_t pf, void *arg) {
  Thread *tp;
  
#if CH_DBG_FILL_THREADS
  _thread_memfill((uint8_t *)wsp,
                  (uint8_t *)wsp + sizeof(Thread),
                  CH_THREAD_FILL_VALUE);
  _thread_memfill((uint8_t *)wsp + sizeof(Thread),
                  (uint8_t *)wsp + size,
                  CH_STACK_FILL_VALUE);
#endif
  chSysLock();
  chSchWakeupS(tp = chThdCreateI(wsp, size, prio, pf, arg), RDY_OK);
  chSysUnlock();
  return tp;
}

/**
 * @brief   Changes the running thread priority level then reschedules if
 *          necessary.
 * @note    The function returns the real thread priority regardless of the
 *          current priority that could be higher than the real priority
 *          because the priority inheritance mechanism.
 *
 * @param[in] newprio   the new priority level of the running thread
 * @return              The old priority level.
 *
 * @api
 */
tprio_t chThdSetPriority(tprio_t newprio) {
  tprio_t oldprio;

  chDbgCheck(newprio <= HIGHPRIO, "chThdSetPriority");

  chSysLock();
#if CH_USE_MUTEXES
  oldprio = currp->p_realprio;
  if ((currp->p_prio == currp->p_realprio) || (newprio > currp->p_prio))
    currp->p_prio = newprio;
  currp->p_realprio = newprio;
#else
  oldprio = currp->p_prio;
  currp->p_prio = newprio;
#endif
  chSchRescheduleS();
  chSysUnlock();
  return oldprio;
}

/**
 * @brief   Resumes a suspended thread.
 * @pre     The specified thread pointer must refer to an initialized thread
 *          in the @p THD_STATE_SUSPENDED state.
 * @post    The specified thread is immediately started or put in the ready
 *          list depending on the relative priority levels.
 * @note    Use this function to start threads created with @p chThdCreateI().
 *
 * @param[in] tp        pointer to the thread
 * @return              The pointer to the thread.
 *
 * @api
 */
Thread *chThdResume(Thread *tp) {

  chSysLock();
  chDbgAssert(tp->p_state == THD_STATE_SUSPENDED,
              "chThdResume(), #1",
              "thread not in THD_STATE_SUSPENDED state");
  chSchWakeupS(tp, RDY_OK);
  chSysUnlock();
  return tp;
}

/**
 * @brief   Requests a thread termination.
 * @pre     The target thread must be written to invoke periodically
 *          @p chThdShouldTerminate() and terminate cleanly if it returns
 *          @p TRUE.
 * @post    The specified thread will terminate after detecting the termination
 *          condition.
 *
 * @param[in] tp        pointer to the thread
 *
 * @api
 */
void chThdTerminate(Thread *tp) {

  chSysLock();
  tp->p_flags |= THD_TERMINATE;
  chSysUnlock();
}

/**
 * @brief   Suspends the invoking thread for the specified time.
 *
 * @param[in] time      the delay in system ticks, the special values are
 *                      handled as follow:
 *                      - @a TIME_INFINITE the thread enters an infinite sleep
 *                        state.
 *                      - @a TIME_IMMEDIATE this value is not allowed.
 *                      .
 *
 * @api
 */
void chThdSleep(systime_t time) {

  chDbgCheck(time != TIME_IMMEDIATE, "chThdSleep");

  chSysLock();
  chThdSleepS(time);
  chSysUnlock();
}

/**
 * @brief   Suspends the invoking thread until the system time arrives to the
 *          specified value.
 *
 * @param[in] time      absolute system time
 *
 * @api
 */
void chThdSleepUntil(systime_t time) {

  chSysLock();
  if ((time -= chTimeNow()) > 0)
    chThdSleepS(time);
  chSysUnlock();
}

/**
 * @brief   Yields the time slot.
 * @details Yields the CPU control to the next thread in the ready list with
 *          equal priority, if any.
 *
 * @api
 */
void chThdYield(void) {

  chSysLock();
  chSchDoYieldS();
  chSysUnlock();
}

/**
 * @brief   Terminates the current thread.
 * @details The thread goes in the @p THD_STATE_FINAL state holding the
 *          specified exit status code, other threads can retrieve the
 *          exit status code by invoking the function @p chThdWait().
 * @post    Eventual code after this function will never be executed,
 *          this function never returns. The compiler has no way to
 *          know this so do not assume that the compiler would remove
 *          the dead code.
 *
 * @param[in] msg       thread exit code
 *
 * @api
 */
void chThdExit(msg_t msg) {

  chSysLock();
  chThdExitS(msg);
  /* The thread never returns here.*/
}

/**
 * @brief   Terminates the current thread.
 * @details The thread goes in the @p THD_STATE_FINAL state holding the
 *          specified exit status code, other threads can retrieve the
 *          exit status code by invoking the function @p chThdWait().
 * @post    Eventual code after this function will never be executed,
 *          this function never returns. The compiler has no way to
 *          know this so do not assume that the compiler would remove
 *          the dead code.
 *
 * @param[in] msg       thread exit code
 *
 * @sclass
 */
void chThdExitS(msg_t msg) {
  Thread *tp = currp;

  tp->p_u.exitcode = msg;
#if defined(THREAD_EXT_EXIT_HOOK)
  THREAD_EXT_EXIT_HOOK(tp);
#endif
#if CH_USE_WAITEXIT
  while (notempty(&tp->p_waiting))
    chSchReadyI(list_remove(&tp->p_waiting));
#endif
#if CH_USE_REGISTRY
  /* Static threads are immediately removed from the registry because
     there is no memory to recover.*/
  if ((tp->p_flags & THD_MEM_MODE_MASK) == THD_MEM_MODE_STATIC)
    REG_REMOVE(tp);
#endif
  chSchGoSleepS(THD_STATE_FINAL);
  /* The thread never returns here.*/
  chDbgAssert(FALSE, "chThdExitS(), #1", "zombies apocalypse");
}

#if CH_USE_WAITEXIT || defined(__DOXYGEN__)
/**
 * @brief   Blocks the execution of the invoking thread until the specified
 *          thread terminates then the exit code is returned.
 * @details This function waits for the specified thread to terminate then
 *          decrements its reference counter, if the counter reaches zero then
 *          the thread working area is returned to the proper allocator.<br>
 *          The memory used by the exited thread is handled in different ways
 *          depending on the API that spawned the thread:
 *          - If the thread was spawned by @p chThdCreateStatic() or by
 *            @p chThdCreateI() then nothing happens and the thread working
 *            area is not released or modified in any way. This is the
 *            default, totally static, behavior.
 *          - If the thread was spawned by @p chThdCreateFromHeap() then
 *            the working area is returned to the system heap.
 *          - If the thread was spawned by @p chThdCreateFromMemoryPool()
 *            then the working area is returned to the owning memory pool.
 *          .
 * @pre     The configuration option @p CH_USE_WAITEXIT must be enabled in
 *          order to use this function.
 * @post    Enabling @p chThdWait() requires 2-4 (depending on the
 *          architecture) extra bytes in the @p Thread structure.
 * @post    After invoking @p chThdWait() the thread pointer becomes invalid
 *          and must not be used as parameter for further system calls.
 * @note    If @p CH_USE_DYNAMIC is not specified this function just waits for
 *          the thread termination, no memory allocators are involved.
 *
 * @param[in] tp        pointer to the thread
 * @return              The exit code from the terminated thread.
 *
 * @api
 */
msg_t chThdWait(Thread *tp) {
  msg_t msg;

  chDbgCheck(tp != NULL, "chThdWait");

  chSysLock();
  chDbgAssert(tp != currp, "chThdWait(), #1", "waiting self");
#if CH_USE_DYNAMIC
  chDbgAssert(tp->p_refs > 0, "chThdWait(), #2", "not referenced");
#endif
  if (tp->p_state != THD_STATE_FINAL) {
    list_insert(currp, &tp->p_waiting);
    chSchGoSleepS(THD_STATE_WTEXIT);
  }
  msg = tp->p_u.exitcode;
  chSysUnlock();
#if CH_USE_DYNAMIC
  chThdRelease(tp);
#endif
  return msg;
}
#endif /* CH_USE_WAITEXIT */

/** @} */