This is the source for the MMUHACK 2.4 kernel module is included with the GP2X backend. This is the code used to build the mmuhack.o module that ships with the GP2X binaries.

-- line, and those below, will be ignored--

A    gp2x/mmuhack
AM   gp2x/mmuhack/flush_uppermem_cache.s
AM   gp2x/mmuhack/flush_uppermem_cache.h
AM   gp2x/mmuhack/mmuhack.c
AM   gp2x/mmuhack/readme.txt
AM   gp2x/mmuhack/Makefile

svn-id: r40449

1 files changed, 129 insertions, 0 deletions

diff --git a/backends/platform/gp2x/mmuhack/mmuhack.c b/backends/platform/gp2x/mmuhack/mmuhack.c
new file mode 100755
index 0000000000..72eef9b055
--- /dev/null
+++ b/backends/platform/gp2x/mmuhack/mmuhack.c
@@ -0,0 +1,129 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * $URL: https://scummvm.svn.sourceforge.net/svnroot/scummvm/scummvm/trunk/backends/platform/gp2x/gp2x-mem.cpp $
+ * $Id: gp2x-mem.cpp 39708 2009-03-27 14:12:42Z dhewg $
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/miscdevice.h>
+#include <asm/memory.h>
+
+#define MMUHACK_MINOR 225
+#define DEVICE_NAME "mmuhack"
+
+#if __GNUC__ == 3
+#include <linux/version.h>
+static const char __module_kernel_version_gcc3[] __attribute__((__used__)) __attribute__((section(".modinfo"))) =
+"kernel_version=" UTS_RELEASE;
+#endif
+
+static ssize_t mmuhack_open(struct inode *inode, struct file *filp)
+{
+    unsigned int *pgtable;
+	unsigned int *cpt;
+    int i, j;
+	int ttb;
+	int ret = -EFAULT;
+
+	// get the pointer to the translation table base...
+	asm volatile(
+		"stmdb sp!, {r0}\n\t"
+		"mrc p15, 0, r0, c2, c0, 0\n\t"
+		"mov %0, r0\n\t"
+		"ldmia sp!, {r0}\n\t": "=r"(ttb)
+	);
+
+	pgtable = __va(ttb);
+
+    for (i = 0; i < 4096; i ++) if ( (pgtable[i] & 3) == 1 ) {
+		cpt = __va(pgtable[i] & 0xfffffc00);
+
+		for (j = 0; j < 256; j ++) {/*
+			if ( (cpt[j] & 0xfe00000f) == 0x02000002 ) {
+				// set C and B bits in upper 32MB memory area...
+				printk("Set C&B bits %08x\n",cpt[j]);
+				cpt[j] |= 0xFFC;
+				ret = 0;
+			}
+					   */
+			if (((cpt[j] & 0xff000000) == 0x02000000) && ((cpt[j] & 12)==0) )
+			{
+				//printk("Set C&B bits %08x\n",cpt[j]);
+				cpt[j] |= 0xFFC;
+			}
+			//if ((a>=0x31 && a<=0x36) && ((cpt[i] & 12)==0))
+			if (((cpt[j] & 0xff000000) == 0x03000000) && ((cpt[j] & 12)==0))
+			{
+				//printk("Set C&B bits %08x\n",cpt[j]);
+				//printf("SDL   c and b bits not set, overwriting\n");
+				cpt[j] |= 0xFFC;
+			}
+		}
+    }
+
+	// drain the write buffer and flush the tlb caches...
+	asm volatile(
+		"stmdb sp!, {r0}\n\t"
+		"mov    r0, #0\n\t"
+		"mcr    15, 0, r0, cr7, cr10, 4\n\t"
+		"mcr    15, 0, r0, cr8, cr7, 0\n\t"
+		"ldmia sp!, {r0}\n\t"
+	);
+
+	if (ret == 0)
+		printk("MMU hack applied.\n");
+
+	return 0;
+}
+
+static struct file_operations mmuhack_fops = {
+    owner:      THIS_MODULE,
+    open:       mmuhack_open,
+};
+
+
+static struct miscdevice mmuhack = {
+    MMUHACK_MINOR, DEVICE_NAME, &mmuhack_fops
+};
+
+static int __init mmuhack_init(void)
+{
+	misc_register(&mmuhack);
+/*
+	printk("MMSP2 MMU Hack module.\n");
+*/
+    return 0;
+}
+
+static void __exit mmuhack_exit(void)
+{
+    misc_deregister(&mmuhack);
+/*
+	printk(KERN_ALERT "MMU Hack module removed.\n");
+*/
+}
+
+module_init(mmuhack_init);
+module_exit(mmuhack_exit);