X-Git-Url: https://notaz.gp2x.de/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fgp2x%2Fmmuhack.c;fp=drivers%2Fgp2x%2Fmmuhack.c;h=c0c218965ed9646ce2cda35397aec76215a53202;hb=937bf65b1c80e9394547e5f105664bd26f3671de;hp=0000000000000000000000000000000000000000;hpb=9115e7d2b5e5b8dc00774fe92db97f1d02b2fee1;p=fceu.git

diff --git a/drivers/gp2x/mmuhack.c b/drivers/gp2x/mmuhack.c
new file mode 100644
index 0000000..c0c2189
--- /dev/null
+++ b/drivers/gp2x/mmuhack.c
@@ -0,0 +1,104 @@
+#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);