/* ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010 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 . */ /** * @file chmtx.c * @brief Mutexes code. * * @addtogroup mutexes * @details Mutexes related APIs and services. * *

Operation mode

* A mutex is a threads synchronization object that can be in two * distinct states: * - Not owned (unlocked). * - Owned by a thread (locked). * . * Operations defined for mutexes: * - Lock: The mutex is checked, if the mutex is not owned by * some other thread then it is associated to the locking thread * else the thread is queued on the mutex in a list ordered by * priority. * - Unlock: The mutex is released by the owner and the highest * priority thread waiting in the queue, if any, is resumed and made * owner of the mutex. * . *

Constraints

* In ChibiOS/RT the Unlock operations are always performed in * lock-reverse order. The unlock API does not even have a parameter, * the mutex to unlock is selected from an internal, per-thread, stack * of owned mutexes. This both improves the performance and is * required for an efficient implementation of the priority * inheritance mechanism. * *

The priority inversion problem

* The mutexes in ChibiOS/RT implements the full priority * inheritance mechanism in order handle the priority inversion * problem.
* When a thread is queued on a mutex, any thread, directly or * indirectly, holding the mutex gains the same priority of the * waiting thread (if their priority was not already equal or higher). * The mechanism works with any number of nested mutexes and any * number of involved threads. The algorithm complexity (worst case) * is N with N equal to the number of nested mutexes. * @pre In order to use the mutex APIs the @p CH_USE_MUTEXES option * must be enabled in @p chconf.h. * @post Enabling mutexes requires 5-12 (depending on the architecture) * extra bytes in the @p Thread structure. * @{ */ #include "ch.h" #if CH_USE_MUTEXES || defined(__DOXYGEN__) /** * @brief Initializes s @p Mutex structure. * * @param[out] mp pointer to a @p Mutex structure * * @init */ void chMtxInit(Mutex *mp) { chDbgCheck(mp != NULL, "chMtxInit"); queue_init(&mp->m_queue); mp->m_owner = NULL; } /** * @brief Locks the specified mutex. * @post The mutex is locked and inserted in the per-thread stack of owned * mutexes. * * @param[in] mp pointer to the @p Mutex structure * * @api */ void chMtxLock(Mutex *mp) { chSysLock(); chMtxLockS(mp); chSysUnlock(); } /** * @brief Locks the specified mutex. * @post The mutex is locked and inserted in the per-thread stack of owned * mutexes. * * @param[in] mp pointer to the @p Mutex structure * * @sclass */ void chMtxLockS(Mutex *mp) { Thread *ctp = currp; chDbgCheck(mp != NULL, "chMtxLockS"); /* Ia the mutex already locked? */ if (mp->m_owner != NULL) { /* Priority inheritance protocol; explores the thread-mutex dependencies boosting the priority of all the affected threads to equal the priority of the running thread requesting the mutex.*/ Thread *tp = mp->m_owner; /* Does the running thread have higher priority than the mutex ownning thread? */ while (tp->p_prio < ctp->p_prio) { /* Make priority of thread tp match the running thread's priority.*/ tp->p_prio = ctp->p_prio; /* The following states need priority queues reordering.*/ switch (tp->p_state) { case THD_STATE_WTMTX: /* Re-enqueues the mutex owner with its new priority.*/ prio_insert(dequeue(tp), (ThreadsQueue *)tp->p_u.wtobjp); tp = ((Mutex *)tp->p_u.wtobjp)->m_owner; continue; #if CH_USE_CONDVARS | CH_USE_SEMAPHORES_PRIORITY | CH_USE_MESSAGES_PRIORITY #if CH_USE_CONDVARS case THD_STATE_WTCOND: #endif #if CH_USE_SEMAPHORES_PRIORITY case THD_STATE_WTSEM: #endif #if CH_USE_MESSAGES_PRIORITY case THD_STATE_SNDMSG: #endif /* Re-enqueues tp with its new priority on the queue.*/ prio_insert(dequeue(tp), (ThreadsQueue *)tp->p_u.wtobjp); break; #endif case THD_STATE_READY: #if CH_DBG_ENABLE_ASSERTS /* Prevents an assertion in chSchReadyI().*/ tp->p_state = THD_STATE_CURRENT; #endif /* Re-enqueues tp with its new priority on the ready list.*/ chSchReadyI(dequeue(tp)); } break; } /* Sleep on the mutex.*/ prio_insert(ctp, &mp->m_queue); ctp->p_u.wtobjp = mp; chSchGoSleepS(THD_STATE_WTMTX); /* It is assumed that the thread performing the unlock operation assigns the mutex to this thread.*/ chDbgAssert(mp->m_owner == ctp, "chMtxLockS(), #1", "not owner"); chDbgAssert(ctp->p_mtxlist == mp, "chMtxLockS(), #2", "not owned"); } else { /* It was 
/*
    ChibiOS/RT - Copyright (C) 2006-2007 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/>.
*/

/*
 * STM32 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 driver
 * is enabled in halconf.h.
 *
 * IRQ priorities:
 * 0xF0         Lowest, priority level reserved for PENDSV.
 * 0xE0...0x40  Normal IRQs priority levels (0x80 used by SYSTICK).
 * 0x30         Used by SVCALL, do not share.
 * 0x20...0x00  Fast interrupts, can preempt the kernel but cannot use it.
 *
 * DMA priorities:
 * 0...3        Lowest...Highest.
 */

/*
 * ADC driver system settings.
 */
#define USE_STM32_ADC1              TRUE
#define STM32_ADC1_DMA_PRIORITY     3
#define STM32_ADC1_IRQ_PRIORITY     0x50
#define STM32_ADC1_DMA_ERROR_HOOK() chSysHalt()

/*
 * CAN driver system settings.
 */
#define USE_STM32_CAN1              TRUE
#define STM32_CAN1_IRQ_PRIORITY     0xB0

/*
 * PWM driver system settings.
 */
#define USE_STM32_PWM1              TRUE
#define USE_STM32_PWM2              FALSE
#define USE_STM32_PWM3              FALSE
#define USE_STM32_PWM4              FALSE
#define STM32_PWM1_IRQ_PRIORITY     0x70
#define STM32_PWM2_IRQ_PRIORITY     0x70
#define STM32_PWM3_IRQ_PRIORITY     0x70
#define STM32_PWM4_IRQ_PRIORITY     0x70

/*
 * SERIAL driver system settings.
 */
#define USE_STM32_USART1            FALSE
#define USE_STM32_USART2            TRUE
#define USE_STM32_USART3            FALSE
#if defined(STM32F10X_HD) || defined(STM32F10X_CL)
#define USE_STM32_UART4             FALSE
#define USE_STM32_UART5             FALSE
#endif
#define STM32_USART1_PRIORITY       0xC0
#define STM32_USART2_PRIORITY       0xC0
#define STM32_USART3_PRIORITY       0xC0
#if defined(STM32F10X_HD) || defined(STM32F10X_CL)
#define STM32_UART4_PRIORITY        0xC0
#define STM32_UART5_PRIORITY        0xC0
#endif

/*
 * SPI driver system settings.
 */
#define USE_STM32_SPI1              TRUE
#define USE_STM32_SPI2              TRUE
#define STM32_SPI1_DMA_PRIORITY     2
#define STM32_SPI2_DMA_PRIORITY     2
#define STM32_SPI1_IRQ_PRIORITY     0xA0
#define STM32_SPI2_IRQ_PRIORITY     0xA0
#define STM32_SPI1_DMA_ERROR_HOOK() chSysHalt()
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-24 14:24:23 +0000