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/*	@(#)txqueue.h	13.2 (RC International) 91/02/05	*/

/*
 *  txqueue.h -- defines the semaphore and txqueue structures
 *
 *	These structures are used with the procedures of sys/kern_txqueue.c
 *	to implement multi-processor semaphores and queues in TX.
 */

#ifndef _TXQUEUE_

#define _TXQUEUE_

/*
 *  prc -- both TX and RTE process structures must begin like this:
 */

struct prc
{
    struct prc	*p_unixlink;	/* unix forward link */
    struct prc	*p_unixbacklink;/* unix back link */
    char	p_processor;	/* which processor owns this process */
    char	rte1;		/* used by RTE */
    short	rte2;		/* used by RTE */
    struct prc	*p_link;	/* txqueue link */
    struct txqueue *p_q;	/* [TX only] txqueue on which we are waiting */
};

/*
 * p_processor bit definitions:
 */
#define P_NULL		0		/* process is alive */
#define UPU_SLEEP	(1 << 0)	/* process is asleep on the UPU */
#define RPU_SLEEP	(1 << 1)	/* process is asleep on the RPU */
#define SIG_AWAKE	(1 << 2)	/* process being awakened by SIGNAL */
#define TIME_AWAKE	(1 << 3)	/* process being awakened by timer */
#define NORMAL_AWAKE	(1 << 4)	/* process being awakened normally */
#define	P_PROC		(UPU_SLEEP | RPU_SLEEP)
#define	P_AWAKE		(SIG_AWAKE | TIME_AWAKE | NORMAL_AWAKE)
#define P_TRASH		(0xffffffff ^ (P_PROC | P_AWAKE))

/*
 *  semaphore -- a place for a list of processes to wait
 */

struct semaphore
{
    unsigned volatile char sem_rcount;	/* number of RPU processes waiting */
					/* or holding semaphore */
    unsigned volatile char sem_ucount;	/* number of UPU processes waiting */
					/* or holding semaphore */
    unsigned volatile char sem_uwait;	/* UPU process is waiting */
    unsigned volatile char sem_rwait;	/* UPU process is waiting */
    volatile struct prc	*sem_owner;	/* current holder of the lock */
    volatile struct prc	*sem_unext;	/* oldest waiting UPU processes */
    volatile struct prc	*sem_ulast;	/* youngest waiting UPU processes */
    volatile struct prc	*sem_rnext;	/* oldest waiting RPU processes */
    volatile struct prc	*sem_rlast;	/* youngest waiting RPU processes */
    struct sem_stat	*sem_stats;	/* statistics block */
};

/*
 * some fields/values which are different between the UPU and RPU
 */

#if	RPU

#define	sem_mycount	sem_rcount
#define	sem_hiscount	sem_ucount
#define	sem_mynext	sem_rnext
#define	sem_hisnext	sem_unext
#define	sem_mylast	sem_rlast
#define	sem_hislast	sem_ulast
#define	sem_mywait	sem_rwait
#define	sem_hiswait	sem_uwait
#define	sems_waits	sems_rwaits
#define	sems_wblock	sems_rwblock
#define	sems_spins	sems_rspins

#else	!RPU

#define	sem_mycount	sem_ucount
#define	sem_hiscount	sem_rcount
#define	sem_mynext	sem_unext
#define	sem_hisnext	sem_rnext
#define	sem_mylast	sem_ulast
#define	sem_hislast	sem_rlast
#define	sem_mywait	sem_uwait
#define	sem_hiswait	sem_rwait
#define	sems_waits	sems_uwaits
#define	sems_wblock	sems_uwblock
#define	sems_spins	sems_uspins

#endif !RPU

/* 
 *  rwlock -- a read/write lock
 */

#define READLOCK  	1
#define WRITELOCK 	2
#define LOCK_MASK 	3
#define IS_LOCKED 	4
#define LEAVE_LOCKED 	8

struct rwlock
{
    short		rw_rcount;	/* reader count */
    short		rw_wcount;	/* writer count (1 or 0) */
    short		rw_wrcount;	/* waiting reader count */
    short		rw_wwcount;	/* waiting writer count */
    struct prc		*rw_owner;	/* write lock owner */
    struct prc		*rw_rnext;	/* oldest waiting reader process */
    struct prc		*rw_rlast;	/* youngest waiting reader process */
    struct prc		*rw_wnext;	/* oldest waiting writer process */
    struct prc		*rw_wlast;	/* youngest waiting writer process */
};

/*
 *  txqueue -- a place to queue messages and/or processes waiting for them
 */

struct txqueue
{
    volatile short	q_pcount;	/* # of procs waiting for a message */
    volatile short	q_mcount;	/* # of messages currently queued */
    volatile struct prc	*q_pnext;	/* oldest in waiting processes list */
    volatile struct prc	*q_plast;	/* youngest in waiting processes list */
    volatile struct msg	*q_mhead;	/* head of message list */
    volatile struct msg	*q_mtail;	/* tail of message list */
    int			q_cause;	/* event cause */
    struct txq_stat	*q_stats;	/* statistics block */
};

/*
 * event macros
 */
#define	e_set(q, cause)		((q)->q_cause = cause)
#define	e_clear(q)		((q)->q_cause = 0)
#define	e_caused(q)		((q)->q_cause)

/*
 *  wakeup_list -- used to queue processes for the other processor to awaken
 */

#define	WL_SIZE		32

struct wakeup_list
{
    unsigned volatile short	wl_in;	  /* input index into wl_list */
    unsigned volatile short	wl_out;	  /* output index into wl_list */
    unsigned volatile short	wl_max;	  /* max number of entries queued */
    unsigned volatile short	wl_spins; /* number of overflow spins */
    volatile struct prc	*wl_list[WL_SIZE];/* list of processes to awaken */
};

/*
 * some macros for manipulation of wakeup_list(s)
 */
#define WL_COUNT(wl) 	(((wl)->wl_in - (wl)->wl_out) & (WL_SIZE - 1))
#define EMPTY_WL(wl) 	((wl)->wl_in == (wl)->wl_out)
#define REMOVE_WL(wl)	((wl)->wl_list[(wl)->wl_out++ & (WL_SIZE - 1)])
#define ADD_WL(p, wl)						\
	{							\
	    if ( WL_COUNT(wl) >= (wl)->wl_max )			\
		new_wl_max(wl);					\
	    (wl)->wl_list[(wl)->wl_in & (WL_SIZE - 1)] = p;	\
	    (wl)->wl_in++;					\
	    wbflush();						\
	    zap;	/* interrupt the other processor */	\
	}

/*
 * Global info used by kern_queue module on both processors - pointed to by
 * tx_info.
 */

struct txqueue_info
{
    spin_t		txqueue_lock;	/* for all of kern_txqueue module */
    struct wakeup_list	upu_hole;	/* wakeup_list for UPU processes */
    struct wakeup_list	rpu_hole;	/* wakeup_list for RPU processes */
    struct txq_stat	*txqstathead;	/* head of txq_stat block list */
    struct sem_stat	*semstathead;	/* head of sem_stat block list */
};

/*
 * qr_ret_t -- return values of queue_remove and e_wait
 */

typedef enum
{
    QR_OK,			/* gave back a message */
    QR_WOULD_BLOCK,		/* would have blocked */
    QR_SIGNALED,		/* a signal occurred */
    QR_TIMEDOUT,		/* time expired */
    QR_CAUSED			/* woken by an event */
} qr_ret_t;



#endif _TXQUEUE_
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