OpenRISC: Miscellaneous

Adds README file, TODO list, and a couple of other pieces that didn't seem
to fit into any other patch.
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

arch/openrisc/README.openrisc

+OpenRISC Linux
+==============
+
+This is a port of Linux to the OpenRISC class of microprocessors; the initial
+target architecture, specifically, is the 32-bit OpenRISC 1000 family (or1k).
+
+For information about OpenRISC processors and ongoing development:
+
+	website		http://openrisc.net
+
+For more information about Linux on OpenRISC, please contact South Pole AB.
+
+	email:		info@southpole.se
+
+	website:	http://southpole.se
+			http://southpoleconsulting.com
+
+---------------------------------------------------------------------
+
+Build instructions for OpenRISC toolchain and Linux
+===================================================
+
+In order to build and run Linux for OpenRISC, you'll need at least a basic
+toolchain and, perhaps, the architectural simulator.  Steps to get these bits
+in place are outlined here.
+
+1)  The toolchain can be obtained from openrisc.net.  Instructions for building
+a toolchain can be found at:
+
+http://openrisc.net/toolchain-build.html
+
+2) or1ksim (optional)
+
+or1ksim is the architectural simulator which will allow you to actually run
+your OpenRISC Linux kernel if you don't have an OpenRISC processor at hand.
+
+	git clone git://openrisc.net/jonas/or1ksim-svn
+
+	cd or1ksim
+	./configure --prefix=$OPENRISC_PREFIX
+	make
+	make install
+
+3)  Linux kernel
+
+Build the kernel as usual
+
+	make ARCH=openrisc defconfig
+	make ARCH=openrisc
+
+4)  Run in architectural simulator
+
+Grab the or1ksim platform configuration file (from the or1ksim source) and
+together with your freshly built vmlinux, run your kernel with the following
+incantation:
+
+	sim -f arch/openrisc/or1ksim.cfg vmlinux
+
+---------------------------------------------------------------------
+
+Terminology
+===========
+
+In the code, the following particles are used on symbols to limit the scope
+to more or less specific processor implementations:
+
+openrisc: the OpenRISC class of processors
+or1k:     the OpenRISC 1000 family of processors
+or1200:   the OpenRISC 1200 processor
+
+---------------------------------------------------------------------
+
+History
+========
+
+18. 11. 2003	Matjaz Breskvar (phoenix@bsemi.com)
+	initial port of linux to OpenRISC/or32 architecture.
+        all the core stuff is implemented and seams usable.
+
+08. 12. 2003	Matjaz Breskvar (phoenix@bsemi.com)
+	complete change of TLB miss handling.
+	rewrite of exceptions handling.
+	fully functional sash-3.6 in default initrd.
+	a much improved version with changes all around.
+
+10. 04. 2004	Matjaz Breskvar (phoenix@bsemi.com)
+	alot of bugfixes all over.
+	ethernet support, functional http and telnet servers.
+	running many standard linux apps.
+
+26. 06. 2004	Matjaz Breskvar (phoenix@bsemi.com)
+	port to 2.6.x
+
+30. 11. 2004	Matjaz Breskvar (phoenix@bsemi.com)
+	lots of bugfixes and enhancments.
+	added opencores framebuffer driver.
+
+09. 10. 2010    Jonas Bonn (jonas@southpole.se)
+	major rewrite to bring up to par with upstream Linux 2.6.36

arch/openrisc/TODO.openrisc

+The OpenRISC Linux port is fully functional and has been tracking upstream
+since 2.6.35.  There are, however, remaining items to be completed within
+the coming months.  Here's a list of known-to-be-less-than-stellar items
+that are due for investigation shortly, i.e. our TODO list:
+
+-- Implement the rest of the DMA API... dma_map_sg, etc.
+
+-- Consolidate usage of memblock and bootmem... move everything over to
+   memblock.
+
+-- Finish the renaming cleanup... there are references to or32 in the code
+   which was an older name for the architecture.  The name we've settled on is
+   or1k and this change is slowly trickling through the stack.  For the time
+   being, or32 is equivalent to or1k.
+
+-- Implement optimized version of memcpy and memset

arch/openrisc/kernel/asm-offsets.c

+/*
+ * OpenRISC asm-offsets.c
+ *
+ * Linux architectural port borrowing liberally from similar works of
+ * others.  All original copyrights apply as per the original source
+ * declaration.
+ *
+ * Modifications for the OpenRISC architecture:
+ * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
+ * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
+ *
+ *      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 used to generate definitions needed by
+ * assembly language modules.
+ *
+ * We use the technique used in the OSF Mach kernel code:
+ * generate asm statements containing #defines,
+ * compile this file to assembler, and then extract the
+ * #defines from the assembly-language output.
+ */
+
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/io.h>
+#include <linux/thread_info.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/processor.h>
+
+#define DEFINE(sym, val) \
+		asm volatile("\n->" #sym " %0 " #val : : "i" (val))
+
+#define BLANK() asm volatile("\n->" : : )
+
+int main(void)
+{
+	/* offsets into the task_struct */
+	DEFINE(TASK_STATE, offsetof(struct task_struct, state));
+	DEFINE(TASK_FLAGS, offsetof(struct task_struct, flags));
+	DEFINE(TASK_PTRACE, offsetof(struct task_struct, ptrace));
+	DEFINE(TASK_THREAD, offsetof(struct task_struct, thread));
+	DEFINE(TASK_MM, offsetof(struct task_struct, mm));
+	DEFINE(TASK_ACTIVE_MM, offsetof(struct task_struct, active_mm));
+
+	/* offsets into thread_info */
+	DEFINE(TI_TASK, offsetof(struct thread_info, task));
+	DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
+	DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));
+	DEFINE(TI_KSP, offsetof(struct thread_info, ksp));
+
+	DEFINE(PT_SIZE, sizeof(struct pt_regs));
+
+	/* Interrupt register frame */
+	DEFINE(STACK_FRAME_OVERHEAD, STACK_FRAME_OVERHEAD);
+	DEFINE(INT_FRAME_SIZE, STACK_FRAME_OVERHEAD + sizeof(struct pt_regs));
+
+	DEFINE(NUM_USER_SEGMENTS, TASK_SIZE >> 28);
+	return 0;
+}

arch/openrisc/kernel/or32_ksyms.c

+/*
+ * OpenRISC or32_ksyms.c
+ *
+ * Linux architectural port borrowing liberally from similar works of
+ * others.  All original copyrights apply as per the original source
+ * declaration.
+ *
+ * Modifications for the OpenRISC architecture:
+ * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
+ * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
+ *
+ *      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.
+ */
+
+#include <linux/module.h>
+#include <linux/elfcore.h>
+#include <linux/sched.h>
+#include <linux/in6.h>
+#include <linux/interrupt.h>
+#include <linux/vmalloc.h>
+#include <linux/semaphore.h>
+
+#include <asm/processor.h>
+#include <asm/uaccess.h>
+#include <asm/checksum.h>
+#include <asm/io.h>
+#include <asm/hardirq.h>
+#include <asm/delay.h>
+#include <asm/pgalloc.h>
+
+#define DECLARE_EXPORT(name) extern void name(void); EXPORT_SYMBOL(name)
+
+/* compiler generated symbols */
+DECLARE_EXPORT(__udivsi3);
+DECLARE_EXPORT(__divsi3);
+DECLARE_EXPORT(__umodsi3);
+DECLARE_EXPORT(__modsi3);
+DECLARE_EXPORT(__muldi3);
+DECLARE_EXPORT(__ashrdi3);
+DECLARE_EXPORT(__ashldi3);
+DECLARE_EXPORT(__lshrdi3);
+
+EXPORT_SYMBOL(__copy_tofrom_user);