A patch that makes NetBSD/x68k kernel use the transparent translation register (%tt0) to map all I/O device space.

gistfile1.diff

Index: include/cpu.h
===================================================================
RCS file: /cvsroot/src/sys/arch/x68k/include/cpu.h,v
retrieving revision 1.56
diff -u -p -r1.56 cpu.h
--- include/cpu.h	2 Feb 2012 16:59:43 -0000	1.56
+++ include/cpu.h	12 Oct 2013 06:04:11 -0000
@@ -152,8 +152,13 @@ int	badbaddr(volatile void*);
  * ``intiolimit'' (defined in locore.s).  Since it is always mapped,
  * conversion between physical and kernel virtual addresses is easy.
  */
+#ifdef USE_TTMAPIO
+#define	IIOV(pa)	((u_int)(pa) | 0x7F000000)
+#define	IIOP(va)	((u_int)(va) & ~0x7F000000)
+#else
 #define	IIOV(pa)	((u_int)(pa) - INTIOBASE + (u_int)intiobase)
 #define	IIOP(va)	((u_int)(va) - (u_int)intiobase + INTIOBASE)
+#endif
 #define	IIOPOFF(pa)	((int)(pa)-INTIOBASE)
 #define	IIOMAPSIZE	btoc(INTIOTOP-INTIOBASE)	/* 4mb */
 
Index: include/vmparam.h
===================================================================
RCS file: /cvsroot/src/sys/arch/x68k/include/vmparam.h,v
retrieving revision 1.35
diff -u -p -r1.35 vmparam.h
--- include/vmparam.h	21 Jan 2012 20:19:55 -0000	1.35
+++ include/vmparam.h	12 Oct 2013 06:04:11 -0000
@@ -101,7 +101,11 @@
 #define VM_MAXUSER_ADDRESS	((vaddr_t)0xFFF00000)
 #define VM_MAX_ADDRESS		((vaddr_t)0xFFF00000)
 #define VM_MIN_KERNEL_ADDRESS	((vaddr_t)0)
+#ifdef USE_TTMAPIO
+#define VM_MAX_KERNEL_ADDRESS	((vaddr_t)(0x7F000000-PAGE_SIZE*NPTEPG))
+#else
 #define VM_MAX_KERNEL_ADDRESS	((vaddr_t)(0-PAGE_SIZE*NPTEPG))
+#endif
 
 /* virtual sizes (bytes) for various kernel submaps */
 #define VM_PHYS_SIZE		(USRIOSIZE*PAGE_SIZE)
Index: x68k/locore.s
===================================================================
RCS file: /cvsroot/src/sys/arch/x68k/x68k/locore.s,v
retrieving revision 1.110
diff -u -p -r1.110 locore.s
--- x68k/locore.s	19 May 2012 08:29:32 -0000	1.110
+++ x68k/locore.s	12 Oct 2013 06:04:12 -0000
@@ -828,10 +828,16 @@ Lstploaddone:
 	movb	#0x01,0x01800003	| set "SUPER" bit
 Ljupiterdone:
 #endif /* JUPITER */
+#ifdef USE_TTMAPIO
+	RELOC(proto040tt0,%a0)
+	movl	%a0@,%d0		| map 0x7f000000 region via %tt0
+#else
 	moveq	#0,%d0			| ensure TT regs are disabled
+#endif
 	.long	0x4e7b0004		| movc d0,itt0
-	.long	0x4e7b0005		| movc d0,itt1
 	.long	0x4e7b0006		| movc d0,dtt0
+	moveq	#0,%d0			| ensure TT1 reg is disabled
+	.long	0x4e7b0005		| movc d0,itt1
 	.long	0x4e7b0007		| movc d0,dtt1
 	.word	0xf4d8			| cinva bc
 	.word	0xf518			| pflusha
@@ -856,6 +862,10 @@ Lnot060cache:
 	movc	%d0,%cacr		| turn on both caches
 	jmp	Lenab1
 Lmotommu2:
+#ifdef USE_TTMAPIO
+	RELOC(protott0,%a0)
+	.long	0xf0100800		| pmove %a0@,%tt0
+#endif
 	pflusha
 #if PGSHIFT == 13
 	movl	#0x82d08b00,%sp@-	| value to load TC with
@@ -1133,6 +1143,14 @@ GLOBAL(fputype)
 GLOBAL(protorp)
 	.long	0,0		| prototype root pointer
 
+#ifdef USE_TTMAPIO
+GLOBAL(protott0)
+	.long	0x7f008543	| prototype transparent translation register 0
+
+GLOBAL(proto040tt0)
+	.long	0x7f00a040	| prototype transparent translation register 0
+#endif
+
 GLOBAL(intiobase)
 	.long	0		| KVA of base of internal IO space
 
Index: x68k/pmap_bootstrap.c
===================================================================
RCS file: /cvsroot/src/sys/arch/x68k/x68k/pmap_bootstrap.c,v
retrieving revision 1.59
diff -u -p -r1.59 pmap_bootstrap.c
--- x68k/pmap_bootstrap.c	25 Feb 2012 02:43:08 -0000	1.59
+++ x68k/pmap_bootstrap.c	12 Oct 2013 06:04:12 -0000
@@ -163,6 +163,10 @@ pmap_bootstrap(paddr_t nextpa, paddr_t f
 	 * Portions of the last segment of KVA space (0xFFC00000 -
 	 * 0xFFFFFFFF) are mapped for the kernel page tables.
 	 *
+	 * In USE_TTMAPIO case, SYSMAP_VA is before 0x7F000000 and the
+	 * last region (0x7F000000 - 0x7FFFFFFF) is used for %tt0 mapping,
+	 * so the last segment of KVA space is at 0x7EC00000 - 0x7EFFFFFF.
+	 *
 	 * XXX cramming two levels of mapping into the single "segment"
 	 * table on the 68040 is intended as a temporary hack to get things
 	 * working.  The 224mb of address space that this allows will most
@@ -211,19 +215,20 @@ pmap_bootstrap(paddr_t nextpa, paddr_t f
 			protoste += (SG4_LEV2SIZE * sizeof(st_entry_t));
 		}
 		/*
-		 * Initialize the final level 1 descriptor to map the next
-		 * block of level 2 descriptors for Sysptmap.
+		 * Initialize the level 1 descriptor corresponding to
+		 * SYSMAP_VA to map the the last block of level 2 descriptors
+		 * for Sysptmap.
 		 */
 		ste = (st_entry_t *)kstpa;
-		ste = &ste[SG4_LEV1SIZE - 1];
+		ste = &ste[SYSMAP_VA >> SG4_SHIFT1];
 		*ste = protoste;
 		/*
-		 * Now initialize the final portion of that block of
+		 * Now initialize the portion of the block of
 		 * descriptors to map Sysmap.
 		 */
 		i = SG4_LEV1SIZE + (nl1desc * SG4_LEV2SIZE);
 		ste = (st_entry_t *)kstpa;
-		ste = &ste[i + SG4_LEV2SIZE - (NPTEPG / SG4_LEV3SIZE)];
+		ste = &ste[i + ((SYSMAP_VA & SG4_MASK2) >> SG4_SHIFT2)];
 		este = &ste[NPTEPG / SG4_LEV3SIZE];
 		protoste = kptmpa | SG_U | SG_RW | SG_V;
 		while (ste < este) {
@@ -267,7 +272,7 @@ pmap_bootstrap(paddr_t nextpa, paddr_t f
 			*pte++ = PG_NV;
 		}
 		/*
-		 * Initialize the last one to point to Sysptmap.
+		 * Initialize the last one to point to SYSMAP_VA.
 		 */
 		pte = (pt_entry_t *)kptmpa;
 		pte = &pte[SYSMAP_VA >> SEGSHIFT];