/*
 * DSP support functions
 */

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

#include	"io.h"

#include	"dsp.h"

enum {
	Ndsp = 2,		/* determined by hardware */

	NHOLES=	64
};

typedef struct DSPparam DSPparam;
struct DSPparam {
	ulong	fdbase;	/* function descriptor table physical base address */
	ulong	fd_ptr;	/* function descriptor pointer */
	ulong	dstate;	/* DSP state */
	ulong	resvd[2];
	ushort	dstatus;	/* current function descriptor status */
	ushort	i;	/* number of iterations */
	ushort	tap;	/* number of TAPs */
	ushort	cbase;
	ushort	anon1;	/* sample buffer size-1 */
	ushort	xptr;	/* pointer to sample */
	ushort	anon2;	/* output buffer size-1 */
	ushort	yptr;	/* pointer to output */
	ushort	m;	/* sample buffer size-1 */
	ushort	anon3;	/* sample buffer pointer */
	ushort	n;	/* output buffer size -1 */
	ushort	anon4;	/* output buffer pointer */
	ushort	k;	/* coefficient buffer size - 1 */
	ushort	anon5;	/* coefficient buffer pointer */
};

struct DSP {
	Lock;	/* protects state */
	void	(*done)(void*);
	void*	arg;
	DSPparam*	par;
	CPMdev*	cpm;

	QLock;	/* protects busyr */
	int	busy;
	Rendez	busyr;
};

static	DSP	dsps[Ndsp];
static	Lock	dsplock;
static	int	dspinit;
static struct {
	QLock;
	ulong	avail;
	Rendez	wantr;
} dspalloc;

static	Map	fndmapv[NHOLES];
static	RMap	fndmap = {"DSP function descriptors"};

static void
dspinterrupt(Ureg*, void*)
{
	int i;
	ushort events;
	DSP *dsp;

	events = m->iomem->sdsr;
	m->iomem->sdsr = events;
	if(events & (1<<7))
		panic("dsp: SDMA channel bus error sdar=#%lux", m->iomem->sdar);
	for(i=0; i<Ndsp; i++)
		if(events & (1<<i)){
			dsp = &dsps[i];
			if(dsp->busy){
				dsp->busy = 0;
				if(dsp->done)
					dsp->done(dsp->arg);
				else
					wakeup(&dsp->busyr);
			}else
				print("dsp%d: empty interrupt\n", i);
		}
}

/*
 * called by system initialisation to set up the DSPs
 */
void
dspinitialise(void)
{
	CPMdev *d;

	ilock(&dsplock);
	if(dspinit == 0){
		mapinit(&fndmap, fndmapv, sizeof(fndmapv));
		d = cpmdev(CPdsp1);
		dsps[0].cpm = d;
		dsps[0].par = d->param;
		d = cpmdev(CPdsp2);
		dsps[1].cpm = d;
		dsps[1].par = d->param;
		intrenable(VectorCPIC+d->irq, dspinterrupt, nil, BUSUNKNOWN, "dsp");
		dspalloc.avail = (1<<Ndsp)-1;
		dspinit = 1;
	}
	iunlock(&dsplock);
}

static int
dspavail(void*)
{
	return dspalloc.avail != 0;
}

/*
 * wait for a DSP to become available, and return a reference to it.
 * if done is not nil, it will be called (with the given arg) when that
 * DSP completes each function (if set to interrupt).
 */
DSP*
dspacquire(void (*done)(void*), void *arg)
{
	DSP *dsp;
	int i;

	if(dspinit == 0)
		dspinitialise();
	qlock(&dspalloc);
	if(waserror()){
		qunlock(&dspalloc);
		nexterror();
	}
	for(i=0;; i++){
		if(i >= Ndsp){
			sleep(&dspalloc.wantr, dspavail, nil);
			i = 0;
		}
		if(dspalloc.avail & (1<<i))
			break;
	}
	dsp = &dsps[i];
	if(dsp->busy)
		panic("dspacquire");
	dsp->done = done;
	dsp->arg = arg;
	poperror();
	qunlock(&dspalloc);
	return dsp;
}

/*
 * relinquish access to the given DSP
 */
void
dsprelease(DSP *dsp)
{
	ulong bit;

	if(dsp == nil)
		return;
	bit = 1 << (dsp-dsps);
	if(dspalloc.avail & bit)
		panic("dsprelease");
	dspalloc.avail |= bit;
	wakeup(&dspalloc.wantr);
}

/*
 * execute f[0] to f[n-1] on the given DSP
 */
void
dspexec(DSP *dsp, FnD *f, ulong n)
{
	dspsetfn(dsp, f, n);
	dspstart(dsp);
}

/*
 * set the DSP to execute f[0] to f[n-1]
 */
void
dspsetfn(DSP *dsp, FnD *f, ulong n)
{
	f[n-1].status |= FnWrap;
	ilock(dsp);
	dsp->par->fdbase = PADDR(f);
	iunlock(dsp);
	cpmop(dsp->cpm, InitDSP, 0);
}

/*
 * start execution of the preset function(s)
 */
void
dspstart(DSP *dsp)
{
	ilock(dsp);
	dsp->busy = 1;
	iunlock(dsp);
	cpmop(dsp->cpm, StartDSP, 0);
}

static int
dspdone(void *a)
{
	return ((DSP*)a)->busy;
}

/*
 * wait until the DSP has completed execution
 */
void
dspsleep(DSP *dsp)
{
	sleep(&dsp->busyr, dspdone, dsp);
}

/*
 * allocate n function descriptors
 */
FnD*
fndalloc(ulong n)
{
	ulong a, nb, pgn;
	FnD *f;

	if(n == 0)
		return nil;
	if(dspinit == 0)
		dspinitialise();
	nb = n*sizeof(FnD);
	while((a = rmapalloc(&fndmap, 0, nb, sizeof(FnD))) != 0){
		/* expected to loop just once, but might lose a race with another dsp user */
		pgn = (nb+BY2PG-1)&~(BY2PG-1);
		a = PADDR(xspanalloc(pgn, sizeof(FnD), 0));
		if(a == 0)
			return nil;
		mapfree(&fndmap, a, pgn);
	}
	f = KADDR(a);
	f[n-1].status = FnWrap;
	return f;
}

/*
 * free n function descriptors
 */
void
fndfree(FnD *f, ulong n)
{
	if(f != nil)
		mapfree(&fndmap, PADDR(f), n*sizeof(FnD));
}

/*
 * allocate an IO buffer region in shared memory for use by the DSP
 */
void*
dspmalloc(ulong n)
{
	ulong i;

	n = (n+3)&~4;
	i = n;
	if(n & (n-1)){
		/* align on a power of two */
		for(i=1; i < n; i <<= 1)
			;
	}
	return cpmalloc(n, i);	/* this seems to be what 16.3.3.2 is trying to say */
}

/*
 * free DSP buffer memory
 */
void
dspfree(void *p, ulong n)
{
	if(p != nil)
		cpmfree(p, (n+3)&~4);
}