From f6fbf32a02daa2aa6a58456fe4a6153c6c410ad4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fran=C3=A7ois=20Revol?= <revol@free.fr>
Date: Tue, 1 Nov 2011 18:58:18 +0000
Subject: [PATCH] Dump the 68040 mmu registers before touching them. Added a
 comment about the Milan clone which uses the mmu in the BIOS to emulate Atari
 hardware, and the Transparent Translation registers to map the PCI bus, which
 screws up with our current code.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@43073 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 src/system/boot/arch/m68k/mmu_040.cpp | 44 ++++++++++++++++++++++++++-
 1 file changed, 43 insertions(+), 1 deletion(-)

diff --git a/src/system/boot/arch/m68k/mmu_040.cpp b/src/system/boot/arch/m68k/mmu_040.cpp
index 69f2f005eb..607b34d75f 100644
--- a/src/system/boot/arch/m68k/mmu_040.cpp
+++ b/src/system/boot/arch/m68k/mmu_040.cpp
@@ -23,7 +23,7 @@
 #include "arch_040_mmu.h"
 
 
-//#define TRACE_MMU
+#define TRACE_MMU
 #ifdef TRACE_MMU
 #	define TRACE(x) dprintf x
 #else
@@ -33,10 +33,52 @@
 
 extern page_root_entry *gPageRoot;
 
+//XXX: the milan BIOS uses the mmu for itself,
+// likely to virtualize missing Atari I/O ports...
+// tcr: c000 (enabled, 8k pages :()
+// dtt0: 803fe140	0x80000000 & ~0x3f... en ignFC2 U=1 CI,S  RW
+// dtt1: 403fe060	0x40000000 & ~0x3f... en ignFC2 U=0 CI,NS RW
+// itt0: 803fe040	0x80000000 & ~0x3f... en ignFC2 U=0 CI,S  RW
+// itt1: 403fe000	0x40000000 & ~0x3f... en ignFC2 U=0 C,WT  RW
+// srp:  00dfde00
+// urp:  00dfde00
+
+static void
+dump_mmu(void)
+{
+	uint32 dttr0, dttr1;
+	uint32 ittr0, ittr1;
+	uint32 srp, urp;
+	uint32 tcr;
+
+	TRACE(("mmu_040:dump:\n"));
+
+	asm volatile("movec %%tcr,%0\n" : "=d"(tcr) :);
+	TRACE(("tcr:\t%08lx\n", tcr));
+
+	asm volatile("movec %%dtt0,%0\n" : "=d"(dttr0) :);
+	TRACE(("dtt0:\t%08lx\n", dttr0));
+	asm volatile("movec %%dtt1,%0\n" : "=d"(dttr1) :);
+	TRACE(("dtt1:\t%08lx\n", dttr1));
+
+	asm volatile("movec %%itt0,%0\n" : "=d"(ittr0) :);
+	TRACE(("itt0:\t%08lx\n", ittr0));
+	asm volatile("movec %%itt1,%0\n" : "=d"(ittr1) :);
+	TRACE(("itt1:\t%08lx\n", ittr1));
+
+	asm volatile("movec %%srp,%0\n" : "=d"(srp) :);
+	TRACE(("srp:\t%08lx\n", srp));
+	asm volatile("movec %%urp,%0\n" : "=d"(urp) :);
+	TRACE(("urp:\t%08lx\n", urp));
+
+	TRACE(("mmu_040:dump:\n"));
+}
+
 
 static void
 initialize(void)
 {
+	dump_mmu();
 	TRACE(("mmu_040:initialize\n"));
 }