shithub: riscv

Download patch

ref: 0ba91ae22a06af3a7561db15973dd98f715cc9eb
parent: aad55ccc2d1e4004574ce96389ee8e5cd9bb2444
author: cinap_lenrek <[email protected]>
date: Tue Nov 3 15:46:09 EST 2020 

pc, pc64: allocate i/o port space for unassigned pci bars, move ioalloc() to port/iomap.c

With some newer UEFI firmware, not all pci bars get
programmed and we have to assign them ourselfs.

This was already done for memory bars. This change
adds the same for i/o port space, by providing a
ioreservewin() function which can be used to allocate
port space within the parent pci-pci bridge window.

Also, the pci code now allocates the pci config
space i/o ports 0xCF8/0xCFC so userspace needs to
use devpnp to access pci config space now. (see
latest realemu change).

Also, this moves the ioalloc()/iofree() code out
of devarch into port/iomap.c as it can be shared
with the ppc mtx kernel.


--- a/sys/src/9/mtx/devarch.c
+++ b/sys/src/9/mtx/devarch.c
@@ -6,28 +6,8 @@
 #include "io.h"
 #include "../port/error.h"
 
-typedef struct IOMap IOMap;
-struct IOMap
-{
-	IOMap	*next;
-	char	tag[13];
-	ulong	start;
-	ulong	end;
-};
-
-static struct
-{
-	Lock;
-	IOMap	*m;
-	IOMap	*free;
-	IOMap	maps[32];		// some initial free maps
-
-	QLock	ql;			// lock for reading map
-} iomap;
-
 enum {
 	Qdir = 0,
-	Qioalloc = 1,
 	Qiob,
 	Qiow,
 	Qiol,
@@ -43,7 +23,6 @@
 
 static Dirtab archdir[] = {
 	".",	{ Qdir, 0, QTDIR },	0,	0555,
-	"ioalloc",	{ Qioalloc, 0 },	0,	0444,
 	"iob",		{ Qiob, 0 },		0,	0660,
 	"iow",		{ Qiow, 0 },		0,	0660,
 	"iol",		{ Qiol, 0 },		0,	0660,
@@ -95,111 +74,12 @@
 void
 ioinit(void)
 {
-	int i;
+	iomapinit(IOSIZE-1);
 
-	for(i = 0; i < nelem(iomap.maps)-1; i++)
-		iomap.maps[i].next = &iomap.maps[i+1];
-	iomap.maps[i].next = nil;
-	iomap.free = iomap.maps;
-
 	// a dummy entry at 2^17
 	ioalloc(0x20000, 1, 0, "dummy");
 }
 
-//
-//	alloc some io port space and remember who it was
-//	alloced to.  if port < 0, find a free region.
-//
-int
-ioalloc(int port, int size, int align, char *tag)
-{
-	IOMap *m, **l;
-	int i;
-
-	lock(&iomap);
-	if(port < 0){
-		// find a free port above 0x400 and below 0x1000
-		port = 0x400;
-		for(l = &iomap.m; *l; l = &(*l)->next){
-			m = *l;
-			i = m->start - port;
-			if(i > size)
-				break;
-			if(align > 0)
-				port = ((port+align-1)/align)*align;
-			else
-				port = m->end;
-		}
-		if(*l == nil){
-			unlock(&iomap);
-			return -1;
-		}
-	} else {
-		// see if the space clashes with previously allocated ports
-		for(l = &iomap.m; *l; l = &(*l)->next){
-			m = *l;
-			if(m->end <= port)
-				continue;
-			if(m->start >= port+size)
-				break;
-			unlock(&iomap);
-			return -1;
-		}
-	}
-	m = iomap.free;
-	if(m == nil){
-		print("ioalloc: out of maps");
-		unlock(&iomap);
-		return port;
-	}
-	iomap.free = m->next;
-	m->next = *l;
-	m->start = port;
-	m->end = port + size;
-	strncpy(m->tag, tag, sizeof(m->tag));
-	m->tag[sizeof(m->tag)-1] = 0;
-	*l = m;
-
-	archdir[0].qid.vers++;
-
-	unlock(&iomap);
-	return m->start;
-}
-
-void
-iofree(int port)
-{
-	IOMap *m, **l;
-
-	lock(&iomap);
-	for(l = &iomap.m; *l; l = &(*l)->next){
-		if((*l)->start == port){
-			m = *l;
-			*l = m->next;
-			m->next = iomap.free;
-			iomap.free = m;
-			break;
-		}
-		if((*l)->start > port)
-			break;
-	}
-	archdir[0].qid.vers++;
-	unlock(&iomap);
-}
-
-int
-iounused(int start, int end)
-{
-	IOMap *m;
-
-	for(m = iomap.m; m; m = m->next){
-		if(start >= m->start && start < m->end
-		|| start <= m->start && end > m->start)
-			return 0; 
-	}
-	return 1;
-}
-
 static void
 checkport(int start, int end)
 {
@@ -243,16 +123,11 @@
 {
 }
 
-enum
-{
-	Linelen= 31,
-};
-
 static long
 archread(Chan *c, void *a, long n, vlong offset)
 {
-	char buf[Linelen+1], *p;
 	int port;
+	uchar *cp;
 	ushort *sp;
 	ulong *lp;
 	IOMap *m;
@@ -266,8 +141,8 @@
 	case Qiob:
 		port = offset;
 		checkport(offset, offset+n);
-		for(p = a; port < offset+n; port++)
-			*p++ = inb(port);
+		for(cp = a; port < offset+n; port++)
+			*cp++ = inb(port);
 		return n;
 
 	case Qiow:
@@ -290,9 +165,6 @@
 			*lp++ = inl(port);
 		return n*4;
 
-	case Qioalloc:
-		break;
-
 	default:
 		if(c->qid.path < narchdir && (fn = readfn[c->qid.path]))
 			return fn(c, a, n, offset);
@@ -299,31 +171,14 @@
 		error(Eperm);
 		break;
 	}
-
-	offset = offset/Linelen;
-	n = n/Linelen;
-	p = a;
-	lock(&iomap);
-	for(m = iomap.m; n > 0 && m != nil; m = m->next){
-		if(offset-- > 0)
-			continue;
-		if(strcmp(m->tag, "dummy") == 0)
-			break;
-		sprint(buf, "%8lux %8lux %-12.12s\n", m->start, m->end-1, m->tag);
-		memmove(p, buf, Linelen);
-		p += Linelen;
-		n--;
-	}
-	unlock(&iomap);
-
-	return p - (char*)a;
+	return 0;
 }
 
 static long
 archwrite(Chan *c, void *a, long n, vlong offset)
 {
-	char *p;
 	int port;
+	uchar *cp;
 	ushort *sp;
 	ulong *lp;
 	Rdwrfn *fn;
@@ -331,10 +186,10 @@
 	switch((ulong)c->qid.path){
 
 	case Qiob:
-		p = a;
+		cp = a;
 		checkport(offset, offset+n);
 		for(port = offset; port < offset+n; port++)
-			outb(port, *p++);
+			outb(port, *cp++);
 		return n;
 
 	case Qiow:
--- a/sys/src/9/mtx/fns.h
+++ b/sys/src/9/mtx/fns.h
@@ -44,8 +44,6 @@
 void	insl(int, void*, int);
 void	intr(Ureg*);
 void	intrenable(int, void (*)(Ureg*, void*), void*, int, char*);
-int	ioalloc(int, int, int, char*);
-void	iofree(int);
 void	ioinit(void);
 int	iprint(char*, ...);
 int	isaconfig(char*, int, ISAConf*);
--- a/sys/src/9/mtx/mkfile
+++ b/sys/src/9/mtx/mkfile
@@ -17,6 +17,7 @@
 	dev.$O\
 	edf.$O\
 	fault.$O\
+	iomap.$O\
 	log.$O\
 	mul64fract.$O\
 	rebootcmd.$O\
--- a/sys/src/9/pc/devarch.c
+++ b/sys/src/9/pc/devarch.c
@@ -7,29 +7,8 @@
 #include "ureg.h"
 #include "../port/error.h"
 
-typedef struct IOMap IOMap;
-struct IOMap
-{
-	IOMap	*next;
-	int	reserved;
-	char	tag[13];
-	ulong	start;
-	ulong	end;
-};
-
-static struct
-{
-	Lock;
-	IOMap	*m;
-	IOMap	*free;
-	IOMap	maps[32];	/* some initial free maps */
-
-	QLock	ql;		/* lock for reading map */
-} iomap;
-
 enum {
 	Qdir = 0,
-	Qioalloc = 1,
 	Qiob,
 	Qiow,
 	Qiol,
@@ -61,7 +40,6 @@
 
 static Dirtab archdir[Qmax] = {
 	".",		{ Qdir, 0, QTDIR },	0,	0555,
-	"ioalloc",	{ Qioalloc, 0 },	0,	0444,
 	"iob",		{ Qiob, 0 },		0,	0660,
 	"iow",		{ Qiow, 0 },		0,	0660,
 	"iol",		{ Qiol, 0 },		0,	0660,
@@ -116,12 +94,8 @@
 ioinit(void)
 {
 	char *excluded;
-	int i;
 
-	for(i = 0; i < nelem(iomap.maps)-1; i++)
-		iomap.maps[i].next = &iomap.maps[i+1];
-	iomap.maps[i].next = nil;
-	iomap.free = iomap.maps;
+	iomapinit(0xffff);
 
 	/*
 	 * This is necessary to make the IBM X20 boot.
@@ -155,160 +129,8 @@
 	}
 }
 
-/*
- * Reserve a range to be ioalloced later.
- * This is in particular useful for exchangable cards, such
- * as pcmcia and cardbus cards.
- */
-int
-ioreserve(int, int size, int align, char *tag)
-{
-	IOMap *m, **l;
-	int i, port;
-
-	lock(&iomap);
-	/* find a free port above 0x400 and below 0x1000 */
-	port = 0x400;
-	for(l = &iomap.m; *l; l = &(*l)->next){
-		m = *l;
-		if (m->start < 0x400) continue;
-		i = m->start - port;
-		if(i > size)
-			break;
-		if(align > 0)
-			port = ((port+align-1)/align)*align;
-		else
-			port = m->end;
-	}
-	if(*l == nil){
-		unlock(&iomap);
-		return -1;
-	}
-	m = iomap.free;
-	if(m == nil){
-		print("ioalloc: out of maps");
-		unlock(&iomap);
-		return port;
-	}
-	iomap.free = m->next;
-	m->next = *l;
-	m->start = port;
-	m->end = port + size;
-	m->reserved = 1;
-	strncpy(m->tag, tag, sizeof(m->tag)-1);
-	m->tag[sizeof(m->tag)-1] = 0;
-	*l = m;
-
-	archdir[0].qid.vers++;
-
-	unlock(&iomap);
-	return m->start;
-}
-
-/*
- *	alloc some io port space and remember who it was
- *	alloced to.  if port < 0, find a free region.
- */
-int
-ioalloc(int port, int size, int align, char *tag)
-{
-	IOMap *m, **l;
-	int i;
-
-	lock(&iomap);
-	if(port < 0){
-		/* find a free port above 0x400 and below 0x1000 */
-		port = 0x400;
-		for(l = &iomap.m; (m = *l) != nil; l = &m->next){
-			if (m->start < 0x400) continue;
-			i = m->start - port;
-			if(i > size)
-				break;
-			if(align > 0)
-				port = ((port+align-1)/align)*align;
-			else
-				port = m->end;
-		}
-		if(m == nil){
-			unlock(&iomap);
-			return -1;
-		}
-	} else {
-		/* Only 64KB I/O space on the x86. */
-		if((port+size) > 0x10000){
-			unlock(&iomap);
-			return -1;
-		}
-		/* see if the space clashes with previously allocated ports */
-		for(l = &iomap.m; (m = *l) != nil; l = &m->next){
-			if(m->end <= port)
-				continue;
-			if(m->reserved && m->start == port && m->end >= port + size) {
-				m->reserved = 0;
-				unlock(&iomap);
-				return m->start;
-			}
-			if(m->start >= port+size)
-				break;
-			unlock(&iomap);
-			return -1;
-		}
-	}
-	m = iomap.free;
-	if(m == nil){
-		print("ioalloc: out of maps");
-		unlock(&iomap);
-		return port;
-	}
-	iomap.free = m->next;
-	m->next = *l;
-	m->start = port;
-	m->end = port + size;
-	strncpy(m->tag, tag, sizeof(m->tag)-1);
-	m->tag[sizeof(m->tag)-1] = 0;
-	*l = m;
-
-	archdir[0].qid.vers++;
-
-	unlock(&iomap);
-	return m->start;
-}
-
-void
-iofree(int port)
-{
-	IOMap *m, **l;
-
-	lock(&iomap);
-	for(l = &iomap.m; (m = *l) != nil; l = &m->next){
-		if(m->start == port){
-			*l = m->next;
-			m->next = iomap.free;
-			iomap.free = m;
-			break;
-		}
-		if(m->start > port)
-			break;
-	}
-	archdir[0].qid.vers++;
-	unlock(&iomap);
-}
-
-int
-iounused(int start, int end)
-{
-	IOMap *m;
-
-	for(m = iomap.m; m != nil; m = m->next){
-		if(start >= m->start && start < m->end
-		|| start <= m->start && end > m->start)
-			return 0;
-	}
-	return 1;
-}
-
 static void
-checkport(uint start, uint end)
+checkport(ulong start, ulong end)
 {
 	if(end < start || end > 0x10000)
 		error(Ebadarg);
@@ -356,14 +178,12 @@
 static long
 archread(Chan *c, void *a, long n, vlong offset)
 {
-	char buf[32], *p;
-	uint port, end;
+	ulong port, end;
+	uchar *cp;
 	ushort *sp;
 	ulong *lp;
 	vlong *vp;
-	IOMap *m;
 	Rdwrfn *fn;
-	int i;
 
 	port = offset;
 	end = port+n;
@@ -373,8 +193,8 @@
 
 	case Qiob:
 		checkport(port, end);
-		for(p = a; port < end; port++)
-			*p++ = inb(port);
+		for(cp = a; port < end; port++)
+			*cp++ = inb(port);
 		return n;
 
 	case Qiow:
@@ -396,7 +216,7 @@
 	case Qmsr:
 		if(n & 7)
 			error(Ebadarg);
-		if((uint)n/8 > -port)
+		if((ulong)n/8 > -port)
 			error(Ebadarg);
 		end = port+(n/8);
 		for(vp = a; port != end; port++)
@@ -404,25 +224,6 @@
 				error(Ebadarg);
 		return n;
 
-	case Qioalloc:
-		lock(&iomap);
-		i = 0;
-		for(m = iomap.m; m != nil; m = m->next){
-			i = snprint(buf, sizeof(buf), "%8lux %8lux %-12.12s\n",
-				m->start, m->end-1, m->tag);
-			offset -= i;
-			if(offset < 0)
-				break;
-		}
-		unlock(&iomap);
-		if(offset >= 0)
-			return 0;
-		if(n > -offset)
-			n = -offset;
-		offset += i;
-		memmove(a, buf+offset, n);
-		return n;
-
 	default:
 		if(c->qid.path < narchdir && (fn = readfn[c->qid.path]))
 			return fn(c, a, n, offset);
@@ -434,8 +235,8 @@
 static long
 archwrite(Chan *c, void *a, long n, vlong offset)
 {
-	uint port, end;
-	char *p;
+	ulong port, end;
+	uchar *cp;
 	ushort *sp;
 	ulong *lp;
 	vlong *vp;
@@ -446,8 +247,8 @@
 	switch((ulong)c->qid.path){
 	case Qiob:
 		checkport(port, end);
-		for(p = a; port < end; port++)
-			outb(port, *p++);
+		for(cp = a; port < end; port++)
+			outb(port, *cp++);
 		return n;
 
 	case Qiow:
@@ -469,7 +270,7 @@
 	case Qmsr:
 		if(n & 7)
 			error(Ebadarg);
-		if((uint)n/8 > -port)
+		if((ulong)n/8 > -port)
 			error(Ebadarg);
 		end = port+(n/8);
 		for(vp = a; port != end; port++)
--- a/sys/src/9/pc/devpccard.c
+++ b/sys/src/9/pc/devpccard.c
@@ -816,7 +816,7 @@
 
 	if(iolen < 512)
 		iolen = 512;
-	iobase = ioreserve(~0, iolen, 0, "cardbus");
+	iobase = ioreserve(-1, iolen, 0, "cardbus");
 	if(iobase == -1)
 		return;
 
--- a/sys/src/9/pc/fns.h
+++ b/sys/src/9/pc/fns.h
@@ -85,11 +85,7 @@
 void	introff(void);
 void	intron(void);
 void	invlpg(ulong);
-void	iofree(int);
 void	ioinit(void);
-int	iounused(int, int);
-int	ioalloc(int, int, int, char*);
-int	ioreserve(int, int, int, char*);
 int	iprint(char*, ...);
 int	isaconfig(char*, int, ISAConf*);
 void*	kaddr(ulong);
--- a/sys/src/9/pc/mkfile
+++ b/sys/src/9/pc/mkfile
@@ -24,6 +24,8 @@
 	dev.$O\
 	edf.$O\
 	fault.$O\
+	iomap.$O\
+	memmap.$O\
 	page.$O\
 	parse.$O\
 	pgrp.$O\
@@ -35,7 +37,6 @@
 	random.$O\
 	rdb.$O\
 	rebootcmd.$O\
-	memmap.$O\
 	segment.$O\
 	syscallfmt.$O\
 	sysfile.$O\
--- a/sys/src/9/pc/pcipc.c
+++ b/sys/src/9/pc/pcipc.c
@@ -528,59 +528,78 @@
 }
 
 static void
-pcireservemem(void)
+pcireserve(void)
 {
+	char tag[64];
 	Pcidev *p;
 	uvlong pa;
+	ulong io;
 	int i;
 
 	/*
-	 * mark all valid physical address space claimed by pci devices
-	 * as in use, so that upaalloc doesn't give it out.
+	 * mark all valid io/mem address space claimed by pci devices
+	 * so that ioreserve/upaalloc doesn't give it out.
 	 */
 	for(p=pciroot; p != nil; p=p->list){
+		snprint(tag, sizeof(tag), "%T", p->tbdf);
 		for(i=0; i<nelem(p->mem); i++){
 			if(p->mem[i].size == 0)
 				continue;
-			if(p->mem[i].bar & 1)
-				continue;
-			if((p->mem[i].bar & ~0xFULL) == 0)
-				continue;
-			upaalloc(p->mem[i].bar&~0xFULL, p->mem[i].size, 0);
+			if(p->mem[i].bar & 1){
+				io = p->mem[i].bar & ~3ULL;
+				if(io == 0)
+					continue;
+				ioreserve(io, p->mem[i].size, 0, tag);
+			} else {
+				pa = p->mem[i].bar & ~0xFULL;
+				if(pa == 0)
+					continue;
+				upaalloc(pa, p->mem[i].size, 0);
+			}
 		}
 	}
 
 	/*
-	 * allocate physical address space for unassigned membars.
+	 * allocate io/mem address space for unassigned membars.
 	 */
 	for(p=pciroot; p != nil; p=p->list){
+		snprint(tag, sizeof(tag), "%T", p->tbdf);
 		for(i=0; i<nelem(p->mem); i++){
 			if(p->mem[i].size == 0)
 				continue;
-			if(p->mem[i].bar & ~0xEULL)
-				continue;
-
-			if(p->parent == nil){
-				pa = upaalloc(-1ULL,
-					p->mem[i].size, p->mem[i].size);
-			} else if(p->mem[i].bar & 8){
-				pa = upaallocwin(p->parent->prefa.bar, p->parent->prefa.size,
-					p->mem[i].size, p->mem[i].size);
-				if(pa == -1ULL)
-					goto Mem;
+			if(p->mem[i].bar & 1){
+				if(p->mem[i].bar & ~0x3ULL)
+					continue;
+				if(p->parent == nil){
+					io = ioreserve(-1, p->mem[i].size, p->mem[i].size, tag);
+				} else {
+					io = ioreservewin(p->parent->ioa.bar, p->parent->ioa.size,
+						p->mem[i].size, p->mem[i].size, tag);
+				}
+				if(io == -1)
+					continue;
+				p->mem[i].bar |= io;
 			} else {
-			Mem:
-				pa = upaallocwin(p->parent->mema.bar, p->parent->mema.size,
-					p->mem[i].size, p->mem[i].size);
+				if(p->mem[i].bar & ~0xFULL)
+					continue;
+				if(p->parent == nil){
+					pa = upaalloc(-1ULL, p->mem[i].size, p->mem[i].size);
+				} else if(p->mem[i].bar & 8){
+					pa = upaallocwin(p->parent->prefa.bar, p->parent->prefa.size,
+						p->mem[i].size, p->mem[i].size);
+					if(pa == -1ULL)
+						goto Mem;
+				} else {
+				Mem:
+					pa = upaallocwin(p->parent->mema.bar, p->parent->mema.size,
+						p->mem[i].size, p->mem[i].size);
+				}
+				if(pa == -1ULL)
+					continue;
+				p->mem[i].bar |= pa;
 			}
-			if(pa == -1ULL)
-				continue;
-
-			p->mem[i].bar |= pa;
 			pcisetbar(p, PciBAR0 + i*4, p->mem[i].bar);
-
-			DBG("%T: bar%d: fixed %.8lluX %d\n",
-				p->tbdf, i, p->mem[i].bar, p->mem[i].size);
+			DBG("%s: bar%d: fixed %.8lluX %d\n", tag, i, p->mem[i].bar, p->mem[i].size);
 		}
 	}
 }
@@ -620,6 +639,9 @@
 			outl(PciADDR, 0x80000000);
 			outb(PciADDR+3, 0);
 			if(inl(PciADDR) & 0x80000000){
+				ioalloc(PciADDR, 4, 0, "pcicfg.addr");
+				ioalloc(PciDATA, 4, 0, "pcicfg.data");
+
 				pcicfgmode = 1;
 				pcimaxdno = 31;
 			}
@@ -634,6 +656,10 @@
 			if(!(n & 0xF0)){
 				outb(PciCSE, 0x0E);
 				if(inb(PciCSE) == 0x0E){
+					ioalloc(PciCSE, 1, 0, "pcicfg.cse");
+					ioalloc(PciFORWARD, 1, 0, "pcicfg.forward");
+					ioalloc(0xC000, 0x1000, 0, "pcicfg.io");
+
 					pcicfgmode = 2;
 					pcimaxdno = 15;
 				}
@@ -705,9 +731,12 @@
 		 */
 		mema = upaalloc(-1ULL, mema, mema);
 		if(mema == -1ULL)
-			panic("pcicfginit: can't allocate pci window");
+			panic("pcicfginit: can't allocate pci mem window");
 
-		ioa = 0x1000;
+		ioa = ioreserve(-1, ioa, ioa, "pci");
+		if(ioa == -1UL)
+			panic("pcicfginit: can't allocate pci io window");
+
 		DBG("Base:  mem=%.8llux io=%lux\n", mema, ioa);
 		pcibusmap(pciroot, &mema, &ioa, 1);
 		DBG("Limit: mem=%.8llux io=%lux\n", mema, ioa);
@@ -714,7 +743,7 @@
 		goto out;
 	}
 
-	pcireservemem();
+	pcireserve();
 
 	if(!nopcirouting)
 		pcirouting();
--- a/sys/src/9/pc64/fns.h
+++ b/sys/src/9/pc64/fns.h
@@ -83,11 +83,7 @@
 void	introff(void);
 void	intron(void);
 void	invlpg(uintptr);
-void	iofree(int);
 void	ioinit(void);
-int	iounused(int, int);
-int	ioalloc(int, int, int, char*);
-int	ioreserve(int, int, int, char*);
 int	iprint(char*, ...);
 int	isaconfig(char*, int, ISAConf*);
 void*	kaddr(uintptr);
--- a/sys/src/9/pc64/mkfile
+++ b/sys/src/9/pc64/mkfile
@@ -22,6 +22,7 @@
 	dev.$O\
 	edf.$O\
 	fault.$O\
+	iomap.$O\
 	memmap.$O\
 	page.$O\
 	parse.$O\
--- /dev/null
+++ b/sys/src/9/port/iomap.c
@@ -1,0 +1,243 @@
+#include "u.h"
+#include "../port/lib.h"
+#include "mem.h"
+#include "dat.h"
+#include "fns.h"
+
+typedef struct IOMap IOMap;
+struct IOMap
+{
+	IOMap	*next;
+	ulong	start;
+	ulong	end;
+	char	reserved;
+	char	tag[13];
+};
+
+static struct
+{
+	Lock;
+	IOMap	*m;
+	IOMap	*free;
+	IOMap	maps[32];	/* some initial free maps */
+
+	ulong	mask;
+} iomap;
+
+static void
+insert(IOMap **l, ulong start, ulong end, char *tag, int reserved)
+{
+	IOMap *m;
+
+	m = iomap.free;
+	if(m != nil)
+		iomap.free = m->next;
+	else
+		m = malloc(sizeof(IOMap));
+	if(m == nil)
+		panic("ioalloc: out of memory");
+
+	m->next = *l;
+	m->start = start;
+	m->end = end;
+	m->reserved = reserved;
+
+	strncpy(m->tag, tag, sizeof(m->tag)-1);
+	m->tag[sizeof(m->tag)-1] = 0;
+
+	*l = m;
+}
+
+/*
+ * Reserve a range to be ioalloced later.
+ * If port is -1, look for a free range above 0x400.
+ */
+int
+ioreserve(ulong port, ulong size, ulong align, char *tag)
+{
+	if(port == -1)
+		return ioreservewin(0x400, -0x400 & iomap.mask, size, align, tag);
+	else
+		return ioreservewin(port, size, size, align, tag);
+}
+
+/*
+ * Find a free region of length "size" within the window [port, port+win)
+ * and reserve it to be ioalloced later.
+ */
+int
+ioreservewin(ulong port, ulong win, ulong size, ulong align, char *tag)
+{
+	IOMap *m, **l;
+
+	if(win == 0 || port & ~iomap.mask || (~port & iomap.mask) < (win-1 & iomap.mask))
+		return -1;
+
+	size = (size + ~iomap.mask) & iomap.mask;
+	if(size == 0 || size > win)
+		return -1;
+
+	if(align){
+		if((align & (align-1)) != 0)
+			return -1;
+		align--;
+	}
+
+	win += port;
+	port = (port+align) & ~align;
+	if(port >= win || win - port < size)
+		return -1;
+
+	lock(&iomap);
+	for(l = &iomap.m; (m = *l) != nil; l = &m->next){
+		if(m->end <= port)
+			continue;
+		if(m->start > port && m->start - port >= size)
+			break;
+		port = m->end;
+		port = (port+align) & ~align;
+		if(port >= win || win - port < size){
+			unlock(&iomap);
+			return -1;
+		}
+	}
+	insert(l, port, port + size, tag, 1);
+	unlock(&iomap);
+
+	return port;
+}
+
+/*
+ * Alloc some io port space and remember who it was
+ * alloced to. If port == -1, find a free region.
+ */
+int
+ioalloc(ulong port, ulong size, ulong align, char *tag)
+{
+	IOMap *m, **l;
+
+	if(port == -1)
+		port = ioreserve(port, size, align, tag);
+
+	size = (size + ~iomap.mask) & iomap.mask;
+	if(size == 0 || port & ~iomap.mask || (~port & iomap.mask) < (size-1 & iomap.mask))
+		return -1;
+
+	lock(&iomap);
+	for(l = &iomap.m; (m = *l) != nil; l = &m->next){
+		if(m->end <= port)
+			continue;
+		if(m->start > port && m->start - port >= size)
+			break;
+		if(m->reserved && m->start <= port && m->end - port >= size){
+			if(m->end - port > size)
+				insert(&m->next, port + size, m->end, m->tag, 1);
+			if(m->start < port){
+				insert(l, m->start, port, m->tag, 1);
+				l = &(*l)->next;
+			}
+			*l = m->next;
+			m->next = iomap.free;
+			iomap.free = m;
+			break;
+		}
+		print("ioalloc: %lux - %lux %s: clashes with: %lux - %lux %s\n",
+			port, port+size-1, tag,
+			m->start, m->end-1, m->tag);
+		unlock(&iomap);
+		return -1;
+	}
+	insert(l, port, port + size, tag, 0);
+	unlock(&iomap);
+
+	return port;
+}
+
+void
+iofree(ulong port)
+{
+	IOMap *m, **l;
+
+	if(port & ~iomap.mask)
+		return;
+
+	lock(&iomap);
+	for(l = &iomap.m; (m = *l) != nil; l = &m->next){
+		if(m->start == port){
+			*l = m->next;
+			m->next = iomap.free;
+			iomap.free = m;
+			break;
+		}
+		if(m->start > port)
+			break;
+	}
+	unlock(&iomap);
+}
+
+int
+iounused(ulong start, ulong end)
+{
+	IOMap *m;
+
+	if(start & ~iomap.mask || end < start)
+		return 0;
+
+	for(m = iomap.m; m != nil; m = m->next){
+		if(m->end <= start)
+			continue;
+		if(m->start >= end)
+			break;
+		if(!m->reserved)
+			return 0;
+	}
+	return 1;
+}
+
+static long
+iomapread(Chan*, void *a, long n, vlong offset)
+{
+	char buf[32];
+	IOMap *m;
+	int i;
+
+	lock(&iomap);
+	i = 0;
+	for(m = iomap.m; m != nil; m = m->next){
+		i = snprint(buf, sizeof(buf), "%8lux %8lux %-12.12s\n",
+			m->start, m->end-1, m->tag);
+		offset -= i;
+		if(offset < 0)
+			break;
+	}
+	unlock(&iomap);
+	if(offset >= 0)
+		return 0;
+	if(n > -offset)
+		n = -offset;
+	offset += i;
+	memmove(a, buf+offset, n);
+	return n;
+}
+
+/*
+ * Initialize the io space port map.
+ * The mask argument defines the valid bits of
+ * a port address, so different architectures
+ * might have different sizes and alignments.
+ */
+void
+iomapinit(ulong mask)
+{
+	int i;
+
+	assert(mask != 0 && (mask >> 31) == 0);
+
+	for(i = 0; i < nelem(iomap.maps)-1; i++)
+		iomap.maps[i].next = &iomap.maps[i+1];
+	iomap.maps[i].next = nil;
+	iomap.free = iomap.maps;
+	iomap.mask = mask;
+
+	addarchfile("ioalloc", 0444, iomapread, nil);
+}
--- a/sys/src/9/port/portfns.h
+++ b/sys/src/9/port/portfns.h
@@ -138,6 +138,12 @@
 long		incref(Ref*);
 void		init0(void);
 void		initseg(void);
+int		ioalloc(ulong, ulong, ulong, char*);
+void		iofree(ulong);
+void		iomapinit(ulong);
+int		ioreserve(ulong, ulong, ulong, char*);
+int		ioreservewin(ulong, ulong, ulong, ulong, char*);
+int		iounused(ulong, ulong);
 int		iprint(char*, ...);
 void		isdir(Chan*);
 int		iseve(void);
--- a/sys/src/9/ppc/fns.h
+++ b/sys/src/9/ppc/fns.h
@@ -50,8 +50,6 @@
 void	intr(Ureg*);
 void	intrenable(int, void (*)(Ureg*, void*), void*, char*);
 void	intrdisable(int, void (*)(Ureg*, void*), void*, char*);
-int	ioalloc(int, int, int, char*);
-void	iofree(int);
 int	iprint(char*, ...);
 int	isaconfig(char*, int, ISAConf*);
 void	kfpinit(void);
--- a/sys/src/9/xen/fns.h
+++ b/sys/src/9/xen/fns.h
@@ -56,7 +56,6 @@
 void	insl(int, void*, int);
 void	intrdisable(int, void (*)(Ureg *, void *), void*, int, char*);
 void	intrenable(int, void (*)(Ureg*, void*), void*, int, char*);
-int	ioalloc(int, int, int, char*);
 void	ioinit(void);
 int	isaconfig(char*, int, ISAConf*);
 void	kbdenable(void);
--- a/sys/src/9/xen/mkfile
+++ b/sys/src/9/xen/mkfile
@@ -22,6 +22,7 @@
 	dev.$O\
 	edf.$O\
 	fault.$O\
+	iomap.$O\
 	page.$O\
 	parse.$O\
 	pgrp.$O\