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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/include/sys/sync.h $ */
/* */
/* OpenPOWER HostBoot Project */
/* */
/* Contributors Listed Below - COPYRIGHT 2011,2014 */
/* [+] Google Inc. */
/* [+] International Business Machines Corp. */
/* */
/* */
/* 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. */
/* */
/* IBM_PROLOG_END_TAG */
#ifndef __SYS_SYNC_H
#define __SYS_SYNC_H
#include <stdint.h>
/**
* Mutex object type
*/
struct _futex_imp_t
{
uint64_t iv_val;
};
typedef _futex_imp_t mutex_t;
/**
* Barrier object type
*/
struct _barrier_imp_t
{
mutex_t iv_mutex;
uint64_t iv_event;
uint64_t iv_missing;
uint64_t iv_count;
};
typedef _barrier_imp_t barrier_t;
#define MUTEX_INITIALIZER {0}
/**
* Conditional variable types
*/
struct _cond_imp_t
{
mutex_t * mutex;
uint64_t sequence;
};
typedef _cond_imp_t sync_cond_t;
#define COND_INITIALIZER {NULL, 0}
enum _FUTEX_OP
{
FUTEX_WAIT,
FUTEX_WAKE,
FUTEX_REQUEUE
};
/**
* @fn barrier_init
* @brief Initialize a barrier object
* @param[out] o_barrier The barrier
* @param[in] i_count The number of tasks to wait on
* @pre an uninitialized barrier object
* @post a valid barrier object
*/
void barrier_init (barrier_t * o_barrier, uint64_t i_count);
/**
* @fn barrier_destroy
* @brief Destroy a barrier
* @param[in] i_barrier The barrier
*/
void barrier_destroy (barrier_t * i_barrier);
/**
* @fn barrier_wait
* @brief Wait on a barrier
* This tasks will block until the barrier count is reached.
* @param[in] i_barrier The barrier
*/
void barrier_wait (barrier_t * i_barrier);
/**
* @fn mutex_init
* @brief Initialize a mutex object
* @param[out] o_mutex the mutex
* @pre an uninitialized mutex object
* @post a valid mutex object
*/
void mutex_init(mutex_t * o_mutex);
/**
* @fn mutex_destroy
* @brief Destroy / uninitialize a mutex object.
* @param[in] i_mutex - the mutex
* @note This does not free the memory associated with the object if the mutex
* was allocated off the heap.
*/
void mutex_destroy(mutex_t * i_mutex);
/**
* @fn mutex_lock
* @brief Obtain a lock on a mutex
* @param[in] i_mutex - The mutex
* @post returns when this task has the lock
*/
void mutex_lock(mutex_t * i_mutex);
/**
* @fn mutex_unlock
* @brief Release a lock on a mutex
* @param[in] i_mutex - the mutex
* @post mutex lock released
*/
void mutex_unlock(mutex_t * i_mutex);
/**
* @fn sync_cond_init
* @brief Initialize a condtional variable
* @param i_cond, The conditional variable
* @post
*/
void sync_cond_init(sync_cond_t * i_cond);
/**
* @fn sync_cond_destroy
* @brief Destroy a conditional variable
* @param i_cond, The conditional variable
*/
void sync_cond_destroy(sync_cond_t * i_cond);
/**
* @fn sync_cond_wait
* @brief Block the calling task until the specified condition is signaled
* @param i_cond, The condition variable
* @param i_mutex, A mutex for which this task has the lock
* @pre This task must have the mutex lock
* @post This task will have the mutex lock
* @note i_mutex will be unlocked while this task is in the wait state.
* @note failing to lock the mutex before calling this function may cause it
* not to block
*/
int sync_cond_wait(sync_cond_t * i_cond, mutex_t * i_mutex);
/**
* @fn sync_cond_signal
* @brief Signal to wake a task waiting on the condition varible.
* @param i_cond, The condition variable
* @pre This task must hold the lock on the mutex used in sync_cond_wait()
* @pre sync_cond_wait() must have been called for conditional variable
* @note failing to unlock the mutex after this call may cause the waiting
* task to remain blocked. If there is more than one task waiting on the
* conditional variable then sync_cond_broadcast() should be used instead.
*/
void sync_cond_signal(sync_cond_t * i_cond);
/**
* @fn sync_cond_broadcast
* @brief Signal to wake all tasks waiting on the condition variable
* @param i_cond, The conditional variable
* @note same restrictions as sync_cond_signal() except this function should
* be used if there is more than one task waiting on the conditional variable.
* There is no guarantee on which waiting task will get the mutex lock first
* when this task unlocks the mutex.
*/
void sync_cond_broadcast(sync_cond_t * i_cond);
/** @fn futex_wait
* @brief Perform a futex-wait operation.
*
* This system call is modeled after 'futex' under Linux.
*
* Will block the user space application until an address is signaled
* for waking. In order to prevent deadlock conditions where the address
* has already changed while the system-call is being processed, the
* address is checked against the currently known value. If the value has
* already changed then the function immediately returns.
*
* @param[in] i_addr - Address to wait for signal on.
* @param[in] i_val - Current value at that address.
*
* @return SUCCESS or EWOULDBLOCK.
*
* A return of EWOULDBLOCK indicates that *i_addr != i_val.
*/
int futex_wait(uint64_t * i_addr, uint64_t i_val);
/** @fn futex_wake
* @brief Peform a futex-wake operation.
*
* This system call is modeled after 'futex' under Linux.
*
* Will awaken a number of tasks currently waiting to be signalled for an
* address.
*
* @param[in] i_addr - The address to signal.
* @param[in] i_count - The maximum number of tasks to awaken.
*
* @return SUCCESS.
*
* If less tasks than i_count are currently blocked, all blocked tasks will
* be awoken.
*/
int futex_wake(uint64_t * i_addr, uint64_t i_count);
#endif
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