mirror of
https://github.com/Telecominfraproject/OpenCellular.git
synced 2026-01-09 17:11:42 +00:00
16e43a3d0d
They are designed to protect shared hardware resources (e.g. I2C controller). Please refrain using them as a general purpose synchronization primitive for the tasks to avoid unintended slippery effects (e.g. priority inversion), use the provided message-passing functions instead for that purpose. The mutex variable (ie the "struct mutex") should be initially filled with 0, but this is the default compiler behavior if you declare it as a global variable. Signed-off-by: Vincent Palatin <vpalatin@chromium.org> BUG=None TEST=make qemu-tests Change-Id: I328f7eadf5257560944dbbbeda0b99d5b24520e8
126 lines
3.5 KiB
C
126 lines
3.5 KiB
C
/* Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
|
|
* Use of this source code is governed by a BSD-style license that can be
|
|
* found in the LICENSE file.
|
|
*/
|
|
|
|
/* Task scheduling / events module for Chrome EC operating system */
|
|
|
|
#ifndef __EC_TASK_H
|
|
#define __EC_TASK_H
|
|
|
|
#include "common.h"
|
|
#include "task_id.h"
|
|
|
|
/**
|
|
* Return true if we are in interrupt context
|
|
*/
|
|
inline int in_interrupt_context(void);
|
|
|
|
/**
|
|
* Send a message to a task and wake it up if it is higher priority than us
|
|
*
|
|
* tskid : identifier of the receiver task
|
|
* from : identifier of the sender of the message
|
|
* wait : after sending, de-schedule the calling task to wait for the answer
|
|
*
|
|
* returns the bitmap of events which have occured.
|
|
*
|
|
* Can be called both in interrupt context and task context.
|
|
*/
|
|
uint32_t task_send_msg(task_id_t tskid, task_id_t from, int wait);
|
|
|
|
/**
|
|
* Return the identifier of the task currently running
|
|
*
|
|
* when called in interrupt context, returns TASK_ID_INVALID
|
|
*/
|
|
task_id_t task_get_current(void);
|
|
|
|
/**
|
|
* Return a pointer to the bitmap of received events of the task.
|
|
*/
|
|
uint32_t *task_get_event_bitmap(task_id_t tsk);
|
|
|
|
/**
|
|
* Waits for the incoming next message.
|
|
*
|
|
* if an event is already pending, it returns it immediatly, else it
|
|
* de-schedules the calling task and wake up the next one in the priority order
|
|
*
|
|
* if timeout_us > 0, it also sets a timer to produce an event after the
|
|
* specified micro-second duration.
|
|
*
|
|
* returns the bitmap of received events (and clear it atomically).
|
|
*/
|
|
uint32_t task_wait_msg(int timeout_us);
|
|
|
|
/**
|
|
* Changes the task scheduled after returning from the exception.
|
|
*
|
|
* If task_send_msg has been called and has set need_resched flag,
|
|
* we re-compute which task is running and eventually swap the context
|
|
* saved on the process stack to restore the new one at exception exit.
|
|
*
|
|
* it must be called from interrupt context !
|
|
* and it is designed to be the last call of the interrupt handler.
|
|
*/
|
|
void task_resched_if_needed(void *excep_return);
|
|
|
|
/* Initializes tasks and interrupt controller. */
|
|
int task_init(void);
|
|
|
|
/* Starts task scheduling. */
|
|
int task_start(void);
|
|
|
|
/* Enables an interrupt. */
|
|
void task_enable_irq(int irq);
|
|
|
|
/* Disables an interrupt. */
|
|
void task_disable_irq(int irq);
|
|
|
|
/* Software-triggers an interrupt. */
|
|
void task_trigger_irq(int irq);
|
|
|
|
struct mutex {
|
|
uint32_t lock;
|
|
uint32_t waiters;
|
|
};
|
|
|
|
/**
|
|
* try to lock the mutex mtx
|
|
* and de-schedule the task if it is already locked by another task.
|
|
*
|
|
* Should not be used in interrupt context !
|
|
*/
|
|
void mutex_lock(struct mutex *mtx);
|
|
|
|
/* Release a mutex previously locked by the same task. */
|
|
void mutex_unlock(struct mutex *mtx);
|
|
|
|
struct irq_priority {
|
|
uint8_t irq;
|
|
uint8_t priority;
|
|
};
|
|
|
|
/**
|
|
* Connects the interrupt handler "routine" to the irq number "irq" and
|
|
* ensures it is enabled in the interrupt controller with the right priority.
|
|
*
|
|
* Note that you MUST pass irq using a LM4_IRQ_* constant from register.h, not
|
|
* as a number, and not as some other #defined constant, because it's
|
|
* stringized and matched up with a weak reference from init.S. (This is still
|
|
* better than passing it as a raw number, because that's more typo-prone.)
|
|
*/
|
|
#define DECLARE_IRQ(irq, routine, priority) \
|
|
void irq_##irq##_handler(void) \
|
|
{ \
|
|
void *ret = __builtin_return_address(0); \
|
|
routine(); \
|
|
task_resched_if_needed(ret); \
|
|
} \
|
|
const struct irq_priority prio_##irq \
|
|
__attribute__((section(".rodata.irqprio"))) \
|
|
= {irq, priority}
|
|
|
|
#endif /* __EC_TASK_H */
|