mmuhack, 6502 tweaks, fskip

[fceu.git] / drivers / gp2x / mmuhack.c

diff --git a/drivers/gp2x/mmuhack.c b/drivers/gp2x/mmuhack.c
new file mode 100644 (file)
index 0000000..c0c2189
--- /dev/null
+++ b/drivers/gp2x/mmuhack.c
@@ -0,0 +1,104 @@
+#include <linux/config.h>\r
+#include <linux/module.h>\r
+#include <linux/kernel.h>\r
+#include <linux/init.h>\r
+#include <linux/miscdevice.h>\r
+#include <asm/memory.h>\r
+\r
+#define MMUHACK_MINOR 225\r
+#define DEVICE_NAME "mmuhack"\r
+\r
+#if __GNUC__ == 3\r
+#include <linux/version.h>\r
+static const char __module_kernel_version_gcc3[] __attribute__((__used__)) __attribute__((section(".modinfo"))) =\r
+"kernel_version=" UTS_RELEASE;\r
+#endif\r
+\r
+static ssize_t mmuhack_open(struct inode *inode, struct file *filp)\r
+{\r
+    unsigned int *pgtable;\r
+       unsigned int *cpt;\r
+    int i, j;\r
+       int ttb;\r
+       int ret = -EFAULT;\r
+\r
+       // get the pointer to the translation table base...\r
+       asm volatile(\r
+               "stmdb sp!, {r0}\n\t"\r
+               "mrc p15, 0, r0, c2, c0, 0\n\t"\r
+               "mov %0, r0\n\t"\r
+               "ldmia sp!, {r0}\n\t": "=r"(ttb)\r
+       );\r
+\r
+       pgtable = __va(ttb);\r
+\r
+    for (i = 0; i < 4096; i ++) if ( (pgtable[i] & 3) == 1 ) {\r
+               cpt = __va(pgtable[i] & 0xfffffc00);\r
+\r
+               for (j = 0; j < 256; j ++) {/*\r
+                       if ( (cpt[j] & 0xfe00000f) == 0x02000002 ) {\r
+                               // set C and B bits in upper 32MB memory area...\r
+                               printk("Set C&B bits %08x\n",cpt[j]);\r
+                               cpt[j] |= 0xFFC;\r
+                               ret = 0;\r
+                       }\r
+                                          */\r
+                       if (((cpt[j] & 0xff000000) == 0x02000000) && ((cpt[j] & 12)==0) )\r
+                       {\r
+                               //printk("Set C&B bits %08x\n",cpt[j]);\r
+                               cpt[j] |= 0xFFC;\r
+                       }\r
+                       //if ((a>=0x31 && a<=0x36) && ((cpt[i] & 12)==0))\r
+                       if (((cpt[j] & 0xff000000) == 0x03000000) && ((cpt[j] & 12)==0))\r
+                       {\r
+                               //printk("Set C&B bits %08x\n",cpt[j]);\r
+                               //printf("SDL   c and b bits not set, overwriting\n");\r
+                               cpt[j] |= 0xFFC;\r
+                       }\r
+               }\r
+    }\r
+\r
+       // drain the write buffer and flush the tlb caches...\r
+       asm volatile(\r
+               "stmdb sp!, {r0}\n\t"\r
+               "mov    r0, #0\n\t"\r
+               "mcr    15, 0, r0, cr7, cr10, 4\n\t"\r
+               "mcr    15, 0, r0, cr8, cr7, 0\n\t"\r
+               "ldmia sp!, {r0}\n\t"\r
+       );\r
+\r
+       if (ret == 0)\r
+               printk("MMU hack applied.\n");\r
+\r
+       return 0;\r
+}\r
+\r
+static struct file_operations mmuhack_fops = {\r
+    owner:      THIS_MODULE,\r
+    open:       mmuhack_open,\r
+};\r
+\r
+\r
+static struct miscdevice mmuhack = {\r
+    MMUHACK_MINOR, DEVICE_NAME, &mmuhack_fops\r
+};\r
+\r
+static int __init mmuhack_init(void)\r
+{\r
+       misc_register(&mmuhack);\r
+/*\r
+       printk("MMSP2 MMU Hack module.\n");\r
+*/\r
+    return 0;\r
+}\r
+\r
+static void __exit mmuhack_exit(void)\r
+{\r
+    misc_deregister(&mmuhack);\r
+/*\r
+       printk(KERN_ALERT "MMU Hack module removed.\n");\r
+*/\r
+}\r
+\r
+module_init(mmuhack_init);\r
+module_exit(mmuhack_exit);\r