/*
	sim_irq.h

	Copyright 2008, 2009 Michel Pollet <buserror@gmail.com>

 	This file is part of simavr.

	simavr 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.

	simavr 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 simavr.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef __SIM_IRQ_H__
#define __SIM_IRQ_H__

#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Internal IRQ system
 * 
 * This subsystem allows any piece of code to "register" a hook to be called when an IRQ is
 * raised. The IRQ definition is up to the module defining it, for example a IOPORT pin change
 * might be an IRQ in which case any piece of code can be notified when a pin has changed state
 * 
 * The notify hooks are chained, and duplicates are filtered out so you can't register a
 * notify hook twice on one particular IRQ
 * 
 * IRQ calling order is not defined, so don't rely on it.
 * 
 * IRQ hook needs to be registered in reset() handlers, ie after all modules init() bits
 * have been called, to prevent race condition of the initialization order.
 */
struct avr_irq_t;

typedef void (*avr_irq_notify_t)(
		struct avr_irq_t * irq,
		uint32_t value,
		void * param);


enum {
	IRQ_FLAG_NOT		= (1 << 0),	//!< change polarity of the IRQ
	IRQ_FLAG_FILTERED	= (1 << 1),	//!< do not "notify" if "value" is the same as previous raise
	IRQ_FLAG_ALLOC		= (1 << 2), //!< this irq structure was malloced via avr_alloc_irq
	IRQ_FLAG_INIT		= (1 << 3), //!< this irq hasn't been used yet
};

/*
 * IRQ Pool structure
 */
typedef struct avr_irq_pool_t {
	int count;						//!< number of irqs living in the pool
	struct avr_irq_t ** irq;		//!< irqs belonging in this pool
} avr_irq_pool_t;

/*!
 * Public IRQ structure
 */
typedef struct avr_irq_t {
	struct avr_irq_pool_t *	pool;	// TODO: migration in progress
	const char * name;
	uint32_t			irq;		//!< any value the user needs
	uint32_t			value;		//!< current value
	uint8_t				flags;		//!< IRQ_* flags
	struct avr_irq_hook_t * hook;	//!< list of hooks to be notified
} avr_irq_t;

//! allocates 'count' IRQs, initializes their "irq" starting from 'base' and increment
avr_irq_t *
avr_alloc_irq(
		avr_irq_pool_t * pool,
		uint32_t base,
		uint32_t count,
		const char ** names /* optional */);
void
avr_free_irq(
		avr_irq_t * irq,
		uint32_t count);

//! init 'count' IRQs, initializes their "irq" starting from 'base' and increment
void
avr_init_irq(
		avr_irq_pool_t * pool,
		avr_irq_t * irq,
		uint32_t base,
		uint32_t count,
		const char ** names /* optional */);
//! 'raise' an IRQ. Ie call their 'hooks', and raise any chained IRQs, and set the new 'value'
void
avr_raise_irq(
		avr_irq_t * irq,
		uint32_t value);
//! this connects a "source" IRQ to a "destination" IRQ
void
avr_connect_irq(
		avr_irq_t * src,
		avr_irq_t * dst);
void
avr_unconnect_irq(
		avr_irq_t * src,
		avr_irq_t * dst);

//! register a notification 'hook' for 'irq' -- 'param' is anything that your want passed back as argument
void
avr_irq_register_notify(
		avr_irq_t * irq,
		avr_irq_notify_t notify,
		void * param);

void
avr_irq_unregister_notify(
		avr_irq_t * irq,
		avr_irq_notify_t notify,
		void * param);

#ifdef __cplusplus
};
#endif

#endif /* __SIM_IRQ_H__ */
