From f454211bc86602a4e98c7cd99aee198d58c2857c Mon Sep 17 00:00:00 2001
From: PatrickvL <pvanlogchem@gmail.com>
Date: Thu, 20 Jul 2017 15:18:59 +0200
Subject: [PATCH] MmMapIoSpace and MmUnmapIoSpace : Write-combined addresses
 are now passed-through

---
 src/CxbxKrnl/CxbxKrnl.h    |  9 ++++++++-
 src/CxbxKrnl/EmuKrnlMm.cpp | 24 +++++++++++++++++++-----
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/src/CxbxKrnl/CxbxKrnl.h b/src/CxbxKrnl/CxbxKrnl.h
index 42b124c99..6d3c88763 100644
--- a/src/CxbxKrnl/CxbxKrnl.h
+++ b/src/CxbxKrnl/CxbxKrnl.h
@@ -84,7 +84,14 @@ typedef uint32 xbaddr;
 
 /*! base addresses of various components */
 #define XBOX_KERNEL_BASE (MM_SYSTEM_PHYSICAL_MAP + XBE_IMAGE_BASE)
-#define XBOX_NV2A_INIT_VECTOR 0xFF000008
+
+#define XBOX_WRITE_COMBINED_BASE 0xF0000000
+#define XBOX_WRITE_COMBINED_SIZE 0x08000000 // - 0xF7FFFFF
+
+#define XBOX_UNCACHED_BASE       0xF8000000
+#define XBOX_UNCACHED_SIZE       0x07F00000 // - 0xFFEFFFFF
+
+#define XBOX_NV2A_INIT_VECTOR    0xFF000008
 
 #define XBOX_FLASH_ROM_BASE      0xFFF00000
 #define XBOX_FLASH_ROM_SIZE      0x00100000 // - 0xFFFFFFF
diff --git a/src/CxbxKrnl/EmuKrnlMm.cpp b/src/CxbxKrnl/EmuKrnlMm.cpp
index aaeee404d..cb8564198 100644
--- a/src/CxbxKrnl/EmuKrnlMm.cpp
+++ b/src/CxbxKrnl/EmuKrnlMm.cpp
@@ -414,9 +414,18 @@ XBSYSAPI EXPORTNUM(177) xboxkrnl::PVOID NTAPI xboxkrnl::MmMapIoSpace
 		LOG_FUNC_ARG(ProtectionType)
 		LOG_FUNC_END;
 
-	// TODO: should this be aligned?
-	PVOID pRet = g_MemoryManager.Allocate(NumberOfBytes);
-	LOG_INCOMPLETE();
+	PVOID pRet;
+
+	// Is it a physical address for hardware devices (flash, NV2A, etc) ?
+	if (PhysicalAddress >= XBOX_WRITE_COMBINED_BASE) { // 0xF0000000
+		// Return physical address as virtual (accesses will go through EmuException) :
+		pRet = (PVOID)PhysicalAddress;
+	}
+	else {
+		// TODO: should this be aligned?
+		pRet = g_MemoryManager.Allocate(NumberOfBytes);
+		LOG_INCOMPLETE();
+	}
 
 	RETURN(pRet);
 }
@@ -611,8 +620,13 @@ XBSYSAPI EXPORTNUM(183) xboxkrnl::NTSTATUS NTAPI xboxkrnl::MmUnmapIoSpace
 		LOG_FUNC_ARG(NumberOfBytes)
 		LOG_FUNC_END;
 
-	g_MemoryManager.Free(BaseAddress);
-	LOG_INCOMPLETE();
+	if ((xbaddr)BaseAddress >= XBOX_WRITE_COMBINED_BASE) { // 0xF0000000
+		// Don't free hardware devices (flash, NV2A, etc)
+	}
+	else {
+		g_MemoryManager.Free(BaseAddress);
+		LOG_INCOMPLETE();
+	}
 
 	RETURN(STATUS_SUCCESS);
 }