From 01e08d2944bf8ed12eac42bf452fff79c40a367f Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Mon, 31 Mar 1997 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1997-03-31

---
 pc/ether8003.c | 10 +++++-----
 pc/fns.h       |  3 ++-
 pc/memory.c    | 40 ++++++++++++++++++++++++++++++----------
 3 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/pc/ether8003.c b/pc/ether8003.c
index 2cb54a7a5ed4bb8652739fc4bbe5271e02118660..66b03998ff6e0e1f296ce4f5076f6bedc7fd74ca 100644
--- a/pc/ether8003.c
+++ b/pc/ether8003.c
@@ -205,11 +205,11 @@ reset(Ether* ether)
 		ether->size = 8*1024;
 
 	/*
-	 * Look for the interface. We read the LAN address ROM
+	 * Look for the interface. Read the LAN address ROM
 	 * and validate the checksum - the sum of all 8 bytes
 	 * should be 0xFF.
-	 * While we're at it, get the (possible) interface chip
-	 * registers, we'll use them to check for aliasing later.
+	 * At the same time, get the (possible) interface chip
+	 * registers, they'll be used later to check for aliasing.
 	 */
 	port = ether->port;
 	sum = 0;
@@ -253,8 +253,8 @@ reset(Ether* ether)
 	}
 	dp8390setea(ether);
 
-	if(umbrmalloc(PADDR(ether->mem), ether->size, 0) == 0)
-		panic("ether8003: 0x%luX unavailable", PADDR(ether->mem));
+	if(umbrwmalloc(PADDR(ether->mem), ether->size, 0) == 0)
+		print("ether8003: warning - 0x%luX unavailable", PADDR(ether->mem));
 
 	return 0;
 }
diff --git a/pc/fns.h b/pc/fns.h
index b7801433aa0be5217dc8ce8a35ca700dcba290a7..90e2d5cba880ce5f1062f579e825b09f2813dc9a 100644
--- a/pc/fns.h
+++ b/pc/fns.h
@@ -97,8 +97,9 @@ void	touser(void*);
 void	trapinit(void);
 int	tas(void*);
 ulong	umbmalloc(ulong, int, int);
-ulong	umbrmalloc(ulong, int, int);
 void	umbfree(ulong, int);
+ulong	umbrwmalloc(ulong, int, int);
+void	umbrwfree(ulong, int);
 ulong	upamalloc(ulong, int, int);
 void	upafree(ulong, int);
 void	vectortable(void);
diff --git a/pc/memory.c b/pc/memory.c
index 0c492cb21bdc3d4d4329b9ddbf27e272fe4cbf9a..2a0ada0ca7a03beb42a8acf28e3ce7e5b0287d52 100644
--- a/pc/memory.c
+++ b/pc/memory.c
@@ -67,11 +67,11 @@ static RMap rmapumb = {
 	&mapumb[63],
 };
 
-static Map mapumbr[8];
-static RMap rmapumbr = {
+static Map mapumbrw[8];
+static RMap rmapumbrw = {
 	"UMB device memory",
-	mapumbr,
-	&mapumbr[7],
+	mapumbrw,
+	&mapumbrw[7],
 };
 
 #define notdef
@@ -85,14 +85,14 @@ dumpmembank(void)
 	maxpa = (nvramread(0x18)<<8)|nvramread(0x17);
 	maxpa1 = (nvramread(0x31)<<8)|nvramread(0x30);
 	maxpa2 = (nvramread(0x16)<<8)|nvramread(0x15);
-	print("maxpa = %uX -> %uX, maxpa1 = %uXm maxpa2 = %uX\n",
+	print("maxpa = %uX -> %uX, maxpa1 = %uX maxpa2 = %uX\n",
 		maxpa, MB+maxpa*KB, maxpa1, maxpa2);
 
 	for(mp = rmapram.map; mp->size; mp++)
 		print("%8.8uX %8.8uX %8.8uX\n", mp->addr, mp->size, mp->addr+mp->size);
 	for(mp = rmapumb.map; mp->size; mp++)
 		print("%8.8uX %8.8uX %8.8uX\n", mp->addr, mp->size, mp->addr+mp->size);
-	for(mp = rmapumbr.map; mp->size; mp++)
+	for(mp = rmapumbrw.map; mp->size; mp++)
 		print("%8.8uX %8.8uX %8.8uX\n", mp->addr, mp->size, mp->addr+mp->size);
 	for(mp = rmapupa.map; mp->size; mp++)
 		print("%8.8uX %8.8uX %8.8uX\n", mp->addr, mp->size, mp->addr+mp->size);
@@ -212,7 +212,7 @@ umbscan(void)
 	while(p < (uchar*)KADDR(0xE0000)){
 		p[0] = 0xCC;
 		p[2*KB-1] = 0xCC;
-		if(p[0] != 0xCC && p[2*KB-1] != 0xCC){
+		if(p[0] != 0xCC || p[2*KB-1] != 0xCC){
 			p[0] = 0x55;
 			p[1] = 0xAA;
 			p[2] = 4;
@@ -223,7 +223,7 @@ umbscan(void)
 			mapfree(&rmapumb, PADDR(p), 2*KB);
 		}
 		else
-			mapfree(&rmapumbr, PADDR(p), 2*KB);
+			mapfree(&rmapumbrw, PADDR(p), 2*KB);
 		p += 2*KB;
 	}
 
@@ -481,16 +481,36 @@ umbfree(ulong addr, int size)
 }
 
 ulong
-umbrmalloc(ulong addr, int size, int align)
+umbrwmalloc(ulong addr, int size, int align)
 {
 	ulong a;
+	uchar *p;
 
-	if(a = mapalloc(&rmapumbr, addr, size, align))
+	if(a = mapalloc(&rmapumbrw, addr, size, align))
 		return KZERO|a;
 
+	/*
+	 * Perhaps the memory wasn't visible before
+	 * the interface is initialised, so try again.
+	 */
+	if((a = umbmalloc(addr, size, align)) == 0)
+		return 0;
+	p = (uchar*)a;
+	p[0] = 0xCC;
+	p[size-1] = 0xCC;
+	if(p[0] == 0xCC && p[size-1] == 0xCC)
+		return a;
+	umbfree(a, size);
+
 	return 0;
 }
 
+void
+umbrwfree(ulong addr, int size)
+{
+	mapfree(&rmapumbrw, addr & ~KZERO, size);
+}
+
 ulong
 upamalloc(ulong addr, int size, int align)
 {