/* Copyright (c) 2010-2011 The Regents of the University of California
 * Barret Rhoden <brho@cs.berkeley.edu>
 * See LICENSE for details.
 *
 * Kernel interface for event/notification delivery and preemption. */

#pragma once

#include <ros/bits/event.h>
#include <ros/atomic.h>
#include <ros/trapframe.h>

#include <ros/ucq.h>
#include <ros/evbitmap.h>
#include <ros/ceq.h>

#define EV_MBOX_UCQ				1
#define EV_MBOX_BITMAP			2
#define EV_MBOX_CEQ				3

/* Structure for storing / receiving event messages.  An overflow causes the
 * bit of the event to get set in the bitmap.  You can also have just the bit
 * sent (and no message). */
struct event_mbox {
	int 						type;
	union {
		struct ucq				ucq;
		struct evbitmap			evbm;
		struct ceq				ceq;
	};
};

/* The kernel sends messages to this structure, which describes how and where
 * to receive messages, including optional IPIs. */
struct event_queue {
	struct event_mbox 			*ev_mbox;
	int							ev_flags;
	bool						ev_alert_pending;
	uint32_t					ev_vcore;
	void						(*ev_handler)(struct event_queue *);
	void						*ev_udata;
};

/* Big version, contains storage space for the ev_mbox.  Never access the
 * internal mbox directly. */
struct event_queue_big {
	struct event_mbox 			*ev_mbox;
	int							ev_flags;
	bool						ev_alert_pending;
	uint32_t					ev_vcore;
	void						(*ev_handler)(struct event_queue *);
	void						*ev_udata;
	struct event_mbox 			ev_imbox;
};

/* Vcore state flags.  K_LOCK means the kernel is writing */
#define VC_K_LOCK				0x001				/* CASing with the kernel */
#define VC_PREEMPTED			0x002				/* VC is preempted */
#define VC_CAN_RCV_MSG			0x004 				/* someone will get msg */
#define VC_UTHREAD_STEALING		0x008				/* Uthread being stolen */
#define VC_SCP_NOVCCTX			0x010				/* can't go into vc ctx */

/* Racy flags, where we don't need the atomics */
#define VC_FPU_SAVED			0x1000				/* valid FPU state in anc */

/* Per-core data about preemptions and notifications */
struct preempt_data {
	struct user_context			vcore_ctx;			/* for preemptions */
	struct ancillary_state		preempt_anc;
	struct user_context			uthread_ctx;		/* for preempts or notifs */
	uintptr_t 					vcore_entry;		/* advertised by the user */
	uintptr_t					vcore_stack;		/* advertised by the user */
	uintptr_t					vcore_tls_desc;		/* advertised by the user */
	atomic_t					flags;
	int							rflags;				/* racy flags */
	bool						notif_disabled;		/* vcore unwilling to recv*/
	bool						notif_pending;		/* notif k_msg on the way */
	struct event_mbox			ev_mbox_public;		/* can be read remotely */
	struct event_mbox			ev_mbox_private;	/* for this vcore only */
};