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/* Copyright (c) 2012 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 "board.h"
#include "common.h"
#include "task_id.h"
/* Task event bitmasks */
#define TASK_EVENT_CUSTOM(x) (x & 0x1fffffff)
#define TASK_EVENT_WAKE (1 << 29) /* task_wake() called on task */
#define TASK_EVENT_MUTEX (1 << 30) /* Mutex unlocking */
#define TASK_EVENT_TIMER (1 << 31) /* Timer expired. For example,
* task_wait_event() timed out before
* receiving another event. */
/* Disable CPU interrupt bit. This might break the system so think really hard
* before using these. There are usually better ways of accomplishing this. */
void interrupt_disable(void);
/* Enable CPU interrupt bit. */
void interrupt_enable(void);
/* Return true if we are in interrupt context. */
inline int in_interrupt_context(void);
/* Set an event for task <tskid> and wake it up if it is higher priority than
* the current task.
*
* event : event bitmap to set (TASK_EVENT_*)
*
* If wait!=0, after setting the event, de-schedule the calling task to wait
* for a response event, then return the bitmap of events which have occured
* (same as task_wait_event()). Ignored in interrupt context.
*
* If wait==0, returns 0.
*
* Can be called both in interrupt context and task context. */
uint32_t task_set_event(task_id_t tskid, uint32_t event, int wait);
/* Wake a task. This sends it the TASK_EVENT_WAKE event. */
static inline void task_wake(task_id_t tskid)
{
task_set_event(tskid, TASK_EVENT_WAKE, 0);
}
/* Return the identifier of the task currently running.
*
* When called in interrupt context, returns TASK_ID_INVALID. */
task_id_t task_get_current(void);
/* Convert an address to the corresponding task ID. The address may be a stack
* pointer or the task data for a task. Returns TASK_ID_INVALID if the address
* does not correspond to a task. */
task_id_t task_from_addr(uint32_t addr);
/* Return a pointer to the bitmap of events of the task. */
uint32_t *task_get_event_bitmap(task_id_t tsk);
/* Wait for the next event.
*
* If one or more events are already pending, returns immediately. Otherwise,
* it de-schedules the calling task and wakes up the next one in the priority
* order.
*
* If timeout_us > 0, it also sets a timer to produce the TASK_EVENT_TIMER
* event after the specified micro-second duration.
*
* Returns the bitmap of received events (and clears it atomically). */
uint32_t task_wait_event(int timeout_us);
/* Prints the list of tasks using the command output channel. This may be
* called from interrupt level. */
void task_print_list(void);
#ifdef CONFIG_TASK_PROFILING
/* Start tracking an interrupt.
*
* This must be called from interrupt context(!) before the interrupt routine
* is called. */
void task_start_irq_handler(void *excep_return);
#else
#define task_start_irq_handler(excep_return)
#endif
/* Change the task scheduled after returning from the exception.
*
* If task_send_event() has been called and has set need_resched flag,
* re-computes which task is running and eventually swaps the context
* saved on the process stack to restore the new one at exception exit.
*
* This must be called from interrupt context(!) and 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_pre_init(void);
/* Starts task scheduling. Does not normally return. */
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);
/* Clears a pending interrupt.
*
* Note that most interrupts can be removed from the pending state simply by
* handling whatever caused the interrupt in the first place. This only needs
* to be called if an interrupt handler disables itself without clearing the
* reason for the interrupt, and then the interrupt is re-enabled from a
* different context. */
void task_clear_pending_irq(int irq);
struct mutex {
uint32_t lock;
uint32_t waiters;
};
/* Try to lock the mutex mtx and de-schedule the current task if mtx is already
* locked by another task.
*
* Must 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;
};
/* Helper macros to build the IRQ handler name */
#define IRQ_BUILD_NAME(prefix, irqnum, postfix) prefix ## irqnum ## postfix
#define IRQ_HANDLER(irqname) IRQ_BUILD_NAME(irq_,irqname,_handler)
/* Connects the interrupt handler "routine" to the irq number "irq" and ensures
* it is enabled in the interrupt controller with the right priority. */
#define DECLARE_IRQ(irq, routine, priority) \
void IRQ_HANDLER(irq)(void) \
{ \
void *ret = __builtin_return_address(0); \
task_start_irq_handler(ret); \
routine(); \
task_resched_if_needed(ret); \
} \
const struct irq_priority IRQ_BUILD_NAME(prio_, irq, ) \
__attribute__((section(".rodata.irqprio"))) \
= {irq, priority}
#endif /* __EC_TASK_H */
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