[PATCH] m68knommu: add start code for COBRA5272 board

From: <gerg@snapgear.com>

Add startup code specific to newly supported COBRA5272 board.

arch/m68knommu/platform/5272/senTec/crt0_ram.S

+/*****************************************************************************/
+
+/*
+ *	crt0_ram.S -- startup code for MCF5272 ColdFire based boards.
+ *
+ *	(C) Copyright 1999-2002, Greg Ungerer (gerg@snapgear.com).
+ *	(C) Copyright 2000, Lineo (www.lineo.com).
+ */
+
+/*****************************************************************************/
+
+#include <linux/config.h>
+#include <linux/threads.h>
+#include <linux/linkage.h>
+#include <asm/segment.h>
+#include <asm/coldfire.h>
+#include <asm/mcfsim.h>
+
+/*****************************************************************************/
+
+/*
+ *	senTec COBRA5272 board, chip select and memory setup.
+ */
+
+#define	MEM_BASE	0x00000000	/* Memory base at address 0 */
+#define	VBR_BASE	MEM_BASE	/* Vector address */
+
+#if defined(CONFIG_RAM16MB)
+#define	MEM_SIZE	0x01000000	/* Memory size 16Mb */
+#elif defined(CONFIG_RAM8MB)
+#define	MEM_SIZE	0x00800000	/* Memory size 8Mb */
+#else
+#define	MEM_SIZE	0x00400000	/* Memory size 4Mb */
+#endif
+
+/*****************************************************************************/
+
+.global	_start
+.global _rambase
+.global _ramvec
+.global	_ramstart
+.global	_ramend
+
+/*****************************************************************************/
+
+.data
+
+/*
+ *	Set up the usable of RAM stuff. Size of RAM is determined then
+ *	an initial stack set up at the end.
+ */
+_rambase:
+.long	0
+_ramvec:
+.long	0
+_ramstart:
+.long	0
+_ramend:
+.long	0
+
+/*****************************************************************************/
+
+.text
+
+/*
+ *	This is the codes first entry point. This is where it all
+ *	begins...
+ */
+
+_start:
+	nop					/* Filler */
+	move.w	#0x2700, %sr			/* No interrupts */
+
+	/*
+	 * Setup VBR here, otherwise buserror remap will not work.
+	 * if dBug was active before (on my SBC with dBug 1.1 of Dec 16 1996)
+	 *
+	 * bkr@cut.de 19990306
+	 *
+	 * Note: this is because dBUG points VBR to ROM, making vectors read
+	 * only, so the bus trap can't be changed. (RS)
+	 */
+	move.l	#VBR_BASE, %a7			/* Note VBR can't be read */
+	movec   %a7, %VBR
+	move.l	%a7, _ramvec			/* Set up vector addr */
+	move.l	%a7, _rambase			/* Set up base RAM addr */
+
+
+	/*
+	 *	Set memory size.
+	 */
+	move.l	#MEM_SIZE, %a0
+
+	move.l	%a0, %d0			/* Mem end addr is in a0 */
+	move.l	%d0, %sp			/* Set up initial stack ptr */
+	move.l	%d0, _ramend			/* Set end ram addr */
+
+	/*
+	 *	Enable CPU internal cache.
+	 */
+	move.l	#0x01000000, %d0		/* Invalidate cache cmd */
+	movec	%d0, %CACR			/* Invalidate cache */
+	move.l	#0x80000100, %d0		/* Setup cache mask */
+	movec	%d0, %CACR			/* Enable cache */
+
+#ifdef CONFIG_ROMFS_FS
+	/*
+	 *	Move ROM filesystem above bss :-)
+	 */
+	lea.l	_sbss, %a0			/* Get start of bss */
+	lea.l	_ebss, %a1			/* Set up destination  */
+	move.l	%a0, %a2			/* Copy of bss start */
+
+	move.l	8(%a0), %d0			/* Get size of ROMFS */
+	addq.l	#8, %d0				/* Allow for rounding */
+	and.l	#0xfffffffc, %d0		/* Whole words */
+
+	add.l	%d0, %a0			/* Copy from end */
+	add.l	%d0, %a1			/* Copy from end */
+	move.l	%a1, _ramstart			/* Set start of ram */
+
+_copy_romfs:
+	move.l	-(%a0), %d0			/* Copy dword */
+	move.l	%d0, -(%a1)
+	cmp.l	%a0, %a2			/* Check if at end */
+	bne	_copy_romfs
+
+#else /* CONFIG_ROMFS_FS */
+	lea.l	_ebss, %a1
+	move.l	%a1, _ramstart
+#endif /* CONFIG_ROMFS_FS */
+
+
+	/*
+	 *	Zero out the bss region.
+	 */
+	lea.l	_sbss, %a0			/* Get start of bss */
+	lea.l	_ebss, %a1			/* Get end of bss */
+	clr.l	%d0				/* Set value */
+_clear_bss:
+	move.l	%d0, (%a0)+			/* Clear each word */
+	cmp.l	%a0, %a1			/* Check if at end */
+	bne	_clear_bss
+
+	/*
+	 *	Load the current thread pointer and stack.
+	 */
+	lea	init_thread_union, %a0
+	lea	0x2000(%a0), %sp
+
+	/*
+	 *	Assember start up done, start code proper.
+	 */
+	jsr	start_kernel			/* Start Linux kernel */
+
+_exit:
+	jmp	_exit				/* Should never get here */
+
+/*****************************************************************************/