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-rw-r--r--backends/platform/gph/devices/gp2x/mmuhack/Makefile11
-rw-r--r--backends/platform/gph/devices/gp2x/mmuhack/flush_uppermem_cache.h11
-rw-r--r--backends/platform/gph/devices/gp2x/mmuhack/flush_uppermem_cache.s6
-rw-r--r--backends/platform/gph/devices/gp2x/mmuhack/mmuhack.c129
-rw-r--r--backends/platform/gph/devices/gp2x/mmuhack/mmuhack.obin0 -> 1720 bytes
-rw-r--r--backends/platform/gph/devices/gp2x/mmuhack/readme.txt110
6 files changed, 267 insertions, 0 deletions
diff --git a/backends/platform/gph/devices/gp2x/mmuhack/Makefile b/backends/platform/gph/devices/gp2x/mmuhack/Makefile
new file mode 100644
index 0000000000..a35d5c2a98
--- /dev/null
+++ b/backends/platform/gph/devices/gp2x/mmuhack/Makefile
@@ -0,0 +1,11 @@
+TARGET = mmuhack
+INCLUDE = -I/opt/gcc-3.4.4-glibc-2.3.6/arm-open2x-linux/sys-include
+CFLAGS = -O2 -DMODULE -D__KERNEL__ ${INCLUDE}
+CC = arm-open2x-linux-gcc
+
+all: ${TARGET}.o
+
+${TARGET}.o: ${TARGET}.c
+
+clean:
+ rm -rf ${TARGET}.o
diff --git a/backends/platform/gph/devices/gp2x/mmuhack/flush_uppermem_cache.h b/backends/platform/gph/devices/gp2x/mmuhack/flush_uppermem_cache.h
new file mode 100644
index 0000000000..520841ace7
--- /dev/null
+++ b/backends/platform/gph/devices/gp2x/mmuhack/flush_uppermem_cache.h
@@ -0,0 +1,11 @@
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+void flush_uppermem_cache(void *start_address, void *end_address, int flags);
+
+#ifdef __cplusplus
+}
+#endif
+
diff --git a/backends/platform/gph/devices/gp2x/mmuhack/flush_uppermem_cache.s b/backends/platform/gph/devices/gp2x/mmuhack/flush_uppermem_cache.s
new file mode 100644
index 0000000000..17628c156a
--- /dev/null
+++ b/backends/platform/gph/devices/gp2x/mmuhack/flush_uppermem_cache.s
@@ -0,0 +1,6 @@
+.global flush_uppermem_cache @ void *start_address, void *end_address, int flags
+
+flush_uppermem_cache:
+ swi #0x9f0002
+ bx lr
+
diff --git a/backends/platform/gph/devices/gp2x/mmuhack/mmuhack.c b/backends/platform/gph/devices/gp2x/mmuhack/mmuhack.c
new file mode 100644
index 0000000000..7e27262e5f
--- /dev/null
+++ b/backends/platform/gph/devices/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.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#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);
diff --git a/backends/platform/gph/devices/gp2x/mmuhack/mmuhack.o b/backends/platform/gph/devices/gp2x/mmuhack/mmuhack.o
new file mode 100644
index 0000000000..475f4a54ae
--- /dev/null
+++ b/backends/platform/gph/devices/gp2x/mmuhack/mmuhack.o
Binary files differ
diff --git a/backends/platform/gph/devices/gp2x/mmuhack/readme.txt b/backends/platform/gph/devices/gp2x/mmuhack/readme.txt
new file mode 100644
index 0000000000..bea49d7d6d
--- /dev/null
+++ b/backends/platform/gph/devices/gp2x/mmuhack/readme.txt
@@ -0,0 +1,110 @@
+About
+-----
+
+This is a module for GP2X 2.4 based Linux kernel, created for developers to use in their
+programs.
+
+Normally the upper 32MB is uncached. This means that reads/writes on the memory
+are always done via the physical memory modules rather than the much faster
+memory built into the processor (called 'cache'). Access to the upper 32MB can
+be sped up by Squidge's MMU hack. The easiest way to use the MMU hack is to add
+and load the MMU hack kernel module into your program.
+
+Note: Building this module requries a GP2X 'kernel' toolchain (i.e. GCC 2.95.*
+for the GP2X stock, 3.* for Open2X).
+
+You can't build this module with the GCC 4 based application toolchains.
+
+Operation
+---------
+
+When loaded into kernel, this module creates /dev/mmuhack device. Whenever
+a program opens that device using open() call, the module traverses all
+memory, which was allocated in 0x02000000-0x03ffffff range by the program via
+using mmap() system call. While doing that, it marks all encountered memory
+as bufferable and cacheable.
+
+The most common use of this is to remove the framebuffer access bottleneck.
+Note that, however, by making the framebuffer cacheable you can cause display
+artifacts. This can happen because parts of your framebuffer may stay in CPU
+cache and not to be written back to the physical memory. The display
+controller only fetches data from the physical memory, so you get incomplete
+image (the memory will most likely contain data from previous frame, so these
+artifacts are better visible during fade effects). The easy way to fix this
+is by using a special ARM Linux system call, which flushes the cache (forces
+the CPU to write data in cache to the physical memory (see section "Flushing
+the cache")).
+
+Using this module affects the whole upper memory area. But in some situations
+this may be not desirable, for example when using ARM940 core in your program
+(ether using 940 libraries like ogg940 and gpu940, or using your custom code,
+which needs uncacheable memory for communication and such). If you need part
+of your upper memory to be cached, and other part not, you should mmap() that
+memory (which you want to be uncached) _after_ doing open("/dev/mmuhack").
+Another way is to modify mmuhack.c to suit your needs and rebuild the module.
+
+
+Usage
+-----
+
+The very first thing to do is to load the kernel module (mmuhack.o) into the
+running kernel. But before that you should try to unload mmuhack module,
+because other program might have left a different version loaded with
+different memory configuration, which may not suit your program.
+
+system("/sbin/rmmod mmuhack");
+system("/sbin/insmod mmuhack.o");
+
+Now you can assume the module is loaded into kernel and open /dev/mmuhack
+device. You don't need to worry about previous calls failing, because in that
+case open() will simply fail and nothing bad will happen.
+
+IMPORTANT: you _must_ do the open() call _after_ you initialize your graphics
+library or allocate your memory, because it can only work with memory which is
+already allocated, it won't affect memory you or your lib allocates after the
+open() call.
+
+int mmufd = open("/dev/mmuhack", O_RDWR);
+if(mmufd < 0)
+{
+ printf("MMU hack failed");
+}
+else
+{
+ printf("MMU hack loaded");
+ close(mmufd);
+}
+
+If the above call succeeded, you are all done.
+I recommend to unload the module when your program exits, because the other
+program may want to load a different mmuhack.o and may fail, because you left
+your mmuhack.o loaded (it does not get unloaded automatically on exit).
+
+system("/sbin/rmmod mmuhack");
+
+
+Flushing the cache
+------------------
+
+If using mmuhack.o causes your program to display artifacts (see "Operation"
+section for explanation), you will need to flush the CPU cache. This should
+be done after finishing every frame and just before flipping your display
+buffer/surface. You will need to add flush_uppermem_cache.s file to your
+Makefile/project and add a call to flush_uppermem_cache() just before final
+framebuffer flip or blit.
+
+flush_uppermem_cache() has 3 parameters. First param is the start address,
+second param is the end address, third one should always be 0. The addresses
+should be virtual ones (most often pointers to the start/end of your
+framebuffer). Example:
+
+flush_uppermem_cache(screen_surface->pixels, screen_surface->pixels + 320*240, 0);
+
+
+Credits
+-------
+
+Original idea/implementation: Squidge (this whole thing is also known as squidgehack)
+Kernel module: NK
+Documentation: notaz
+