plan9fox/sys/src/9/mtx/devarch.c

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

enum {
	Qdir = 0,
	Qiob,
	Qiow,
	Qiol,
	Qbase,

	Qmax = 16,
};

typedef long Rdwrfn(Chan*, void*, long, vlong);

static Rdwrfn *readfn[Qmax];
static Rdwrfn *writefn[Qmax];

static Dirtab archdir[] = {
	".",	{ Qdir, 0, QTDIR },	0,	0555,
	"iob",		{ Qiob, 0 },		0,	0660,
	"iow",		{ Qiow, 0 },		0,	0660,
	"iol",		{ Qiol, 0 },		0,	0660,
};
Lock archwlock;	/* the lock is only for changing archdir */
int narchdir = Qbase;
int (*_pcmspecial)(char *, ISAConf *);
void (*_pcmspecialclose)(int);

/*
 * Add a file to the #P listing.  Once added, you can't delete it.
 * You can't add a file with the same name as one already there,
 * and you get a pointer to the Dirtab entry so you can do things
 * like change the Qid version.  Changing the Qid path is disallowed.
 */
Dirtab*
addarchfile(char *name, int perm, Rdwrfn *rdfn, Rdwrfn *wrfn)
{
	int i;
	Dirtab d;
	Dirtab *dp;

	memset(&d, 0, sizeof d);
	strcpy(d.name, name);
	d.perm = perm;

	lock(&archwlock);
	if(narchdir >= Qmax){
		unlock(&archwlock);
		return nil;
	}

	for(i=0; i<narchdir; i++)
		if(strcmp(archdir[i].name, name) == 0){
			unlock(&archwlock);
			return nil;
		}

	d.qid.path = narchdir;
	archdir[narchdir] = d;
	readfn[narchdir] = rdfn;
	writefn[narchdir] = wrfn;
	dp = &archdir[narchdir++];
	unlock(&archwlock);

	return dp;
}

void
ioinit(void)
{
	iomapinit(IOSIZE-1);

	// a dummy entry at 2^17
	ioalloc(0x20000, 1, 0, "dummy");
}

static void
checkport(int start, int end)
{
	/* standard vga regs are OK */
	if(start >= 0x2b0 && end <= 0x2df+1)
		return;
	if(start >= 0x3c0 && end <= 0x3da+1)
		return;

	if(iounused(start, end))
		return;
	error(Eperm);
}

static Chan*
archattach(char* spec)
{
	return devattach('P', spec);
}

Walkqid*
archwalk(Chan* c, Chan *nc, char** name, int nname)
{
	return devwalk(c, nc, name, nname, archdir, narchdir, devgen);
}

static int
archstat(Chan* c, uchar* dp, int n)
{
	return devstat(c, dp, n, archdir, narchdir, devgen);
}

static Chan*
archopen(Chan* c, int omode)
{
	return devopen(c, omode, archdir, nelem(archdir), devgen);
}

static void
archclose(Chan*)
{
}

static long
archread(Chan *c, void *a, long n, vlong offset)
{
	int port;
	uchar *cp;
	ushort *sp;
	ulong *lp;
	IOMap *m;
	Rdwrfn *fn;

	switch((ulong)c->qid.path){

	case Qdir:
		return devdirread(c, a, n, archdir, nelem(archdir), devgen);

	case Qiob:
		port = offset;
		checkport(offset, offset+n);
		for(cp = a; port < offset+n; port++)
			*cp++ = inb(port);
		return n;

	case Qiow:
		if((n & 0x01) || (offset & 0x01))
			error(Ebadarg);
		checkport(offset, offset+n+1);
		n /= 2;
		sp = a;
		for(port = offset; port < offset+n; port += 2)
			*sp++ = ins(port);
		return n*2;

	case Qiol:
		if((n & 0x03) || (offset & 0x03))
			error(Ebadarg);
		checkport(offset, offset+n+3);
		n /= 4;
		lp = a;
		for(port = offset; port < offset+n; port += 4)
			*lp++ = inl(port);
		return n*4;

	default:
		if(c->qid.path < narchdir && (fn = readfn[c->qid.path]))
			return fn(c, a, n, offset);
		error(Eperm);
		break;
	}
	return 0;
}

static long
archwrite(Chan *c, void *a, long n, vlong offset)
{
	int port;
	uchar *cp;
	ushort *sp;
	ulong *lp;
	Rdwrfn *fn;

	switch((ulong)c->qid.path){

	case Qiob:
		cp = a;
		checkport(offset, offset+n);
		for(port = offset; port < offset+n; port++)
			outb(port, *cp++);
		return n;

	case Qiow:
		if((n & 01) || (offset & 01))
			error(Ebadarg);
		checkport(offset, offset+n+1);
		n /= 2;
		sp = a;
		for(port = offset; port < offset+n; port += 2)
			outs(port, *sp++);
		return n*2;

	case Qiol:
		if((n & 0x03) || (offset & 0x03))
			error(Ebadarg);
		checkport(offset, offset+n+3);
		n /= 4;
		lp = a;
		for(port = offset; port < offset+n; port += 4)
			outl(port, *lp++);
		return n*4;

	default:
		if(c->qid.path < narchdir && (fn = writefn[c->qid.path]))
			return fn(c, a, n, offset);
		error(Eperm);
		break;
	}
	return 0;
}

Dev archdevtab = {
	'P',
	"arch",

	devreset,
	devinit,
	devshutdown,
	archattach,
	archwalk,
	archstat,
	archopen,
	devcreate,
	archclose,
	archread,
	devbread,
	archwrite,
	devbwrite,
	devremove,
	devwstat,
};

int
pcmspecial(char *idstr, ISAConf *isa)
{
	return (_pcmspecial  != nil)? _pcmspecial(idstr, isa): -1;
}

void
pcmspecialclose(int a)
{
	if (_pcmspecialclose != nil)
		_pcmspecialclose(a);
}