#include	"u.h"
#include	"../port/lib.h"
#include	"mem.h"
#include	"dat.h"
#include	"fns.h"
#include	"ureg.h"
#include	"io.h"
#include	"../port/error.h"

enum 
{
	Maxhandler=	MaxVector		/* max number of interrupt handlers, assuming none shared */
};

enum {
	/* UIC registers (p. 10-4) */
	Usr =	0xC0,	/* status */
	Uer =	0xC2,	/* enable */
	Ucr =	0xC3,	/* critical interrupts */
	Upr =	0xC4,	/* priority */
	Utr =		0xC5,	/* trigger */
	Umsr =	0xC6,	/* masked status */
	Uvr =	0xC7,	/* vector */
	Uvcr =	0xC8,	/* vector configuration */
};

typedef struct Handler	Handler;
struct Handler
{
	void	(*r)(Ureg*, void*);
	void	*arg;
	char	name[KNAMELEN];
	Handler	*next;
	int	edge;
	ulong	nintr;
	ulong	ticks;
	int	maxtick;
};

static Lock	veclock;

static struct
{
	Handler	*ivec[MaxVector];
	Handler	h[Maxhandler];
	int	free;
	Handler*	freelist;
} halloc;

Instr BREAK = 0x7fe00008;
int (*breakhandler)(Ureg*, Proc*);

void	kernfault(Ureg*, int);

char *excname[] =
{
	"reserved 0",
	"system reset",
	"machine check",
	"data access",
	"instruction access",
	"external interrupt",
	"alignment",
	"program exception",
	"floating-point unavailable",
	"decrementer",
	"i/o controller interface error",
	"reserved B",
	"system call",
	"trace trap",
	"floating point assist",
	"reserved F",
	"software emulation",
	"ITLB miss",
	"DTLB miss",
	"ITLB error",
	"DTLB error",
	"reserved 15",
	"reserved 16",
	"reserved 17",
	"reserved 18",
	"reserved 19",
	"reserved 1A",
	"reserved 1B",
	"data breakpoint",
	"instruction breakpoint",
	"peripheral breakpoint",
	"development port",
	/* the following are made up on a program exception */
	"floating point exception",		/* 20: FPEXC */
	"illegal instruction",	/* 21 */
	"privileged instruction",	/* 22 */
	"trap",	/* 23 */
	"illegal operation",	/* 24 */
	"breakpoint",	/* 25 */
};

char *fpcause[] =
{
	"inexact operation",
	"division by zero",
	"underflow",
	"overflow",
	"invalid operation",
};
char	*fpexcname(Ureg*, ulong, char*);
#define FPEXPMASK	0xfff80300		/* Floating exception bits in fpscr */

char *regname[]={
	"CAUSE",	"SRR1",
	"PC",		"GOK",
	"LR",		"CR",
	"XER",	"CTR",
	"R0",		"R1",
	"R2",		"R3",
	"R4",		"R5",
	"R6",		"R7",
	"R8",		"R9",
	"R10",	"R11",
	"R12",	"R13",
	"R14",	"R15",
	"R16",	"R17",
	"R18",	"R19",
	"R20",	"R21",
	"R22",	"R23",
	"R24",	"R25",
	"R26",	"R27",
	"R28",	"R29",
	"R30",	"R31",
};

void
sethvec(int v, void (*r)(void))
{
	ulong *vp, pa, o;

	vp = (ulong*)KADDR(v);
	vp[0] = 0x7c1043a6;	/* MOVW R0, SPR(SPRG0) */
	vp[1] = 0x7c0802a6;	/* MOVW LR, R0 */
	vp[2] = 0x7c1243a6;	/* MOVW R0, SPR(SPRG2) */
	pa = PADDR(r);
	o = pa >> 25;
	if(o != 0 && o != 0x7F){
		/* a branch too far: running from ROM */
		vp[3] = (15<<26)|(pa>>16);	/* MOVW $r&~0xFFFF, R0 */
		vp[4] = (24<<26)|(pa&0xFFFF);	/* OR $r&0xFFFF, R0 */
		vp[5] = 0x7c0803a6;	/* MOVW	R0, LR */
		vp[6] = 0x4e800021;	/* BL (LR) */
	}else
		vp[3] = (18<<26)|(pa&0x3FFFFFC)|3;	/* bla */
	dcflush(vp, 8*sizeof(ulong));
}

void
sethvec2(int v, void (*r)(void))
{
	ulong *vp;

	vp = (ulong*)KADDR(v);
	vp[0] = (18<<26)|((ulong)r&~KSEGM)|2;	/* ba */
	dcflush(vp, sizeof(*vp));
}

static void
faultpower(Ureg *ur, ulong addr, int read)
{
	char buf[ERRMAX];

	if(up == nil){
		dumpregs(ur);
		panic("kernel fault");
	}

	up->dbgreg = ur;		/* For remote ACID */
	spllo();

	sprint(buf, "trap: fault %s pc=0x%lux addr=0x%lux",
			read? "read": "write", ur->pc, addr);
	if(up->type == Interp){
		if(addr == ~0)
			disfault(ur, "dereference of nil");
		disfault(ur, buf);
	}
	dumpregs(ur);
	panic("fault: %s\n", buf);
}

void
trap(Ureg *ur)
{
	int ecode, s;
	ulong w, esr;
	char buf[ERRMAX];

	ecode = ur->cause >> 8;
	if(ecode < 0 || ecode >= 0x1F)
		ecode = 0x1F;
	esr = getesr();
	putesr(0);
	switch(ecode){
	case CPIT:
		clockintr(ur);
		preemption(1);
		break;

	case CMCHECK:
		if(esr & ESR_MCI){
			faultpower(ur, ur->pc, 1);
			break;
		}
		/* FALL THROUGH */
	case CDSI:
		faultpower(ur, getdear(), !(esr&ESR_DST));
		break;

	case CDMISS:
		faultpower(ur, getdear(), 1);
		break;

	case CISI:
	case CIMISS:
		faultpower(ur, ur->pc, 1);
		break;

	case CPROG:
		if(esr & ESR_PIL){
			if(up == nil)
				goto Default;
			if((ulong)(ur+1) != ur->r1)
				panic("fp emu stack");
			spllo();
			if(waserror()){
				if(up->type == Interp)
					disfault(ur, up->env->errstr);
				panic("%s", up->env->errstr);
			}
			if(fpipower(ur) == 0){
				splhi();
				poperror();
				print("pc=#%lux op=#%8.8lux\n", ur->pc, *(ulong*)ur->pc);	/* temporary */
				goto Default;
			}
			poperror();
			break;
		}
		/* TO DO: 4xx variant for the following */
		if(ur->status & (1<<19)) {
			ecode = 0x20;
			w = ur->pc;
			if(ur->status & (1<<16))
				w += 4;
			if(*(ulong*)w == 0x7fe00008){ /* tw 31,0,0 */
				if(breakhandler){
					s = (*breakhandler)(ur, up);
					if(s == BrkSched){
						if(up){
							up->preempted = 0;
							sched();
							splhi();
						}
					}else if(s == BrkNoSched){
						if(up){
							up->preempted = 1;	/* stop it being preempted until next instruction */
							up->dbgreg = 0;
						}
					}
					break;
				}
				ecode = 0x1D;	/* breakpoint */
			}
		}
		if(ur->status & (1<<18))
			ecode = 0x21;
		if(ur->status & (1<<17))
			ecode = 0x22;
		/* FALL THROUGH */

	Default:
	default:
		if(up && up->type == Interp) {
			spllo();
			snprint(buf, sizeof buf, "sys: trap: %s pc=0x%lux", excname[ecode], ur->pc);
			error(buf);
			break;
		}
		print("kernel %s pc=0x%lux\n", excname[ecode], ur->pc);
		dumpregs(ur);
		dumpstack();
		if(m->machno == 0)
			spllo();
		exit(1);
	}

	splhi();
}

void
trapinit(void)
{
	int i;

	putdcr(Uer, 0);	/* none enabled */
	putdcr(Ucr, 0);	/* none are critical by default */
	putdcr(Upr, ~IBIT(VectorPCISERR));	/* default is active high (except PCISERR) */
	putdcr(Utr, 0);	/* all are level sensitive by default */
	putdcr(Usr, getdcr(Usr));	/* reset interrupts */
	putdcr(Uvcr, 0);	/* 31 is highest priority */
	eieio();

	/*
	 * set all exceptions to trap
	 */
	for(i = 0x0; i < 0x3000; i += 0x100)
		sethvec(i, trapvec);

	/* on the 405, several traps are critical interrupts with different SRRs */
	sethvec(0x0100, trapcvec);
	sethvec(0x0200, trapcvec);

	sethvec(CEI<<8, intrvec);
	/* TO DO: FIT and WDT */
	//sethvec2(CIMISS<<8, itlbmiss);
	//sethvec2(CDMISS<<8, dtlbmiss);

	putevpr(0);	/* use our vectors */
}

void
intrenable(int v, void (*r)(Ureg*, void*), void *arg, int, char *name)
{
	Handler *h;
	ulong w, f, bit;

	f = v;
	v &= IRQmask;
	bit = IBIT(v);
	if(v < 0 || v >= nelem(halloc.ivec))
		panic("intrenable(%d)", v);
	ilock(&veclock);
	if((h = halloc.freelist) == nil){
		if(halloc.free >= Maxhandler){
			iunlock(&veclock);
			panic("out of interrupt handlers");
		}
		h = &halloc.h[halloc.free++];
	}else
		halloc.freelist = h->next;
	h->r = r;
	h->arg = arg;
	strncpy(h->name, name, KNAMELEN-1);
	h->name[KNAMELEN-1] = 0;
	h->next = halloc.ivec[v];
	halloc.ivec[v] = h;

	/*
	 * enable corresponding interrupt in UIC
	 */
	w = getdcr(Ucr);
	if(f & IRQcritical)
		putdcr(Ucr, w | bit);
	else
		putdcr(Ucr, w & ~bit);
	if(v >= VectorIRQ){
		/* (only) these have got choice of polarity, etc. */
		w = getdcr(Utr);
		h->edge = (f & IRQedge) != 0;
		if(h->edge)
			putdcr(Utr, w | bit);
		else
			putdcr(Utr, w & ~bit);
		w = getdcr(Upr);
		if(f & IRQactivelow)
			putdcr(Upr, w | bit);
		else
			putdcr(Upr, w & ~bit);
	}
	eieio();
	putdcr(Uer, getdcr(Uer) | bit);
	eieio();
	iunlock(&veclock);
}

static void
irqdisable(int v)
{
	putdcr(Uer, getdcr(Uer) & ~IBIT(v));
}

void
intrdisable(int v, void (*r)(Ureg*, void*), void *arg, int, char *name)
{
	Handler *h, **hp;

	v &= IRQmask;
	if(v < 0 || v >= nelem(halloc.ivec))
		panic("intrdisable(%d)", v);
	ilock(&veclock);
	for(hp = &halloc.ivec[v]; (h = *hp) != nil; hp = &h->next)
		if(h->r == r && h->arg == arg && strcmp(h->name, name) == 0){
			*hp = h->next;
			h->next = halloc.freelist;
			halloc.freelist = h;
			break;
		}
	if(halloc.ivec[v] == nil)
		irqdisable(v);
	iunlock(&veclock);
}

/*
 * called directly by l.s:/intrvec.  on a multiprocessor we'd need to lock veclock.
 */
void
intr(Ureg *ur)
{
	ulong msr, b;
	int v;
	Handler *h;
	long t0;
	Proc *oup;

	oup = up;
	up = nil;	/* no process at interrupt level */
	while((msr = getdcr(Umsr)) != 0){
		for(v=0; msr!=0 && v<32; v++){
			b = IBIT(v);
			if((msr & b) == 0)
				continue;
			msr &= ~b;
			ur->cause = (CEI<<8) | v;
			h = halloc.ivec[v];
			if(h == nil){
				iprint("unknown interrupt %d pc=0x%lux\n", v, ur->pc);
				irqdisable(v);
				continue;
			}

			/*
			 *  call the interrupt handlers
			 */
			do {
				if(h->edge)
					putdcr(Usr, b);
				h->nintr++;
				t0 = getpit();
				(*h->r)(ur, h->arg);
				t0 -= getpit();
				h->ticks += t0;
				if(h->maxtick < t0)
					h->maxtick = t0;
				if(!h->edge)
					putdcr(Usr, b);
				h = h->next;
			} while(h != nil);
		}
	}
	up = oup;
	preemption(0);
}

int
intrstats(char *buf, int bsize)
{
	Handler *h;
	int i, n;

	n = 0;
	for(i=0; i<nelem(halloc.ivec) && n < bsize; i++)
		if((h = halloc.ivec[i]) != nil && h->nintr)
			n += snprint(buf+n, bsize-n, "%3d %lud %lud %ud\n", i, h->nintr, h->ticks, h->maxtick);
	return n;
}

char*
fpexcname(Ureg *ur, ulong fpscr, char *buf)
{
	int i;
	char *s;
	ulong fppc;

	fppc = ur->pc;
	s = 0;
	fpscr >>= 3;		/* trap enable bits */
	fpscr &= (fpscr>>22);	/* anded with exceptions */
	for(i=0; i<5; i++)
		if(fpscr & (1<<i))
			s = fpcause[i];
	if(s == 0)
		return "no floating point exception";
	sprint(buf, "%s fppc=0x%lux", s, fppc);
	return buf;
}

#define KERNPC(x)	(KTZERO<(ulong)(x)&&(ulong)(x)<(ulong)etext)

void
kernfault(Ureg *ur, int code)
{
	Label l;

	print("panic: kfault %s dear=0x%lux esr=0x%8.8lux\n", excname[code], getdear(), getesr());
	print("u=0x%lux status=0x%lux pc=0x%lux sp=0x%lux\n",
				up, ur->status, ur->pc, ur->sp);
	dumpregs(ur);
	l.sp = ur->sp;
	l.pc = ur->pc;
	dumpstack();
	setpri(PriBackground);		/* Let the debugger in */
	for(;;)
		sched();
}

void
dumpstack(void)
{
	ulong l, v;
	int i;

	if(up == 0)
		return;
	i = 0;
	for(l=(ulong)&l; l<(ulong)(up->kstack+KSTACK); l+=4){
		v = *(ulong*)l;
		if(KTZERO < v && v < (ulong)etext){
			print("%lux=%lux, ", l, v);
			if(i++ == 4){
				print("\n");
				i = 0;
			}
		}
	}
}

void
dumpregs(Ureg *ur)
{
	int i;
	ulong *l;
	if(up) {
		print("registers for %s %ld\n", up->text, up->pid);
		if(ur->usp < (ulong)up->kstack ||
		   ur->usp > (ulong)up->kstack+KSTACK)
			print("invalid stack ptr\n");
	}
	else
		print("registers for kernel\n");

	l = &ur->cause;
	for(i=0; i<sizeof regname/sizeof(char*); i+=2, l+=2)
		print("%s\t%.8lux\t%s\t%.8lux\n", regname[i], l[0], regname[i+1], l[1]);
}

static void
linkproc(void)
{
	spllo();
	(*up->kpfun)(up->arg);
	pexit("", 0);
}

void
kprocchild(Proc *p, void (*func)(void*), void *arg)
{
	p->sched.pc = (ulong)linkproc;
	p->sched.sp = (ulong)p->kstack+KSTACK;

	p->kpfun = func;
	p->arg = arg;
}

void
setpanic(void)
{
	consoleprint = 1;
iprint("panic\n");
}

void
dumplongs(char*, ulong*, int)
{
}