arch/m68k/platform/coldfire/head.S - kernel/lockdown - Git at Google

 /*****************************************************************************/

 /*
  *	head.S -- common startup code for ColdFire CPUs.
  *
  *	(C) Copyright 1999-2011, Greg Ungerer <gerg@snapgear.com>.
  */

 /*****************************************************************************/

 #include <linux/linkage.h>
 #include <linux/init.h>
 #include <asm/asm-offsets.h>
 #include <asm/coldfire.h>
 #include <asm/mcfsim.h>
 #include <asm/mcfmmu.h>
 #include <asm/thread_info.h>

 /*****************************************************************************/

 /*
  *	If we don't have a fixed memory size, then lets build in code
  *	to auto detect the DRAM size. Obviously this is the preferred
  *	method, and should work for most boards. It won't work for those
  *	that do not have their RAM starting at address 0, and it only
  *	works on SDRAM (not boards fitted with SRAM).
  */
 #if CONFIG_RAMSIZE != 0
 .macro GET_MEM_SIZE
 	movel	#CONFIG_RAMSIZE,%d0	/* hard coded memory size */
 .endm

 #elif defined(CONFIG_M5206) || defined(CONFIG_M5206e) || \
       defined(CONFIG_M5249) || defined(CONFIG_M525x) || \
       defined(CONFIG_M527x) || defined(CONFIG_M528x) || \
       defined(CONFIG_M5307) || defined(CONFIG_M5407)
 /*
  *	Not all these devices have exactly the same DRAM controller,
  *	but the DCMR register is virtually identical - give or take
  *	a couple of bits. The only exception is the 5272 devices, their
  *	DRAM controller is quite different.
  */
 .macro GET_MEM_SIZE
 	movel	MCFSIM_DMR0,%d0		/* get mask for 1st bank */
 	btst	#0,%d0			/* check if region enabled */
 	beq	1f
 	andl	#0xfffc0000,%d0
 	beq	1f
 	addl	#0x00040000,%d0		/* convert mask to size */
 1:
 	movel	MCFSIM_DMR1,%d1		/* get mask for 2nd bank */
 	btst	#0,%d1			/* check if region enabled */
 	beq	2f
 	andl	#0xfffc0000,%d1
 	beq	2f
 	addl	#0x00040000,%d1
 	addl	%d1,%d0			/* total mem size in d0 */
 2:
 .endm

 #elif defined(CONFIG_M5272)
 .macro GET_MEM_SIZE
 	movel	MCFSIM_CSOR7,%d0	/* get SDRAM address mask */
 	andil	#0xfffff000,%d0		/* mask out chip select options */
 	negl	%d0			/* negate bits */
 .endm

 #elif defined(CONFIG_M520x)
 .macro GET_MEM_SIZE
 	clrl	%d0
 	movel	MCFSIM_SDCS0, %d2	/* Get SDRAM chip select 0 config */
 	andl	#0x1f, %d2		/* Get only the chip select size */
 	beq	3f			/* Check if it is enabled */
 	addql	#1, %d2			/* Form exponent */
 	moveql	#1, %d0
 	lsll	%d2, %d0		/* 2 ^ exponent */
 3:
 	movel	MCFSIM_SDCS1, %d2	/* Get SDRAM chip select 1 config */
 	andl	#0x1f, %d2		/* Get only the chip select size */
 	beq	4f			/* Check if it is enabled */
 	addql	#1, %d2			/* Form exponent */
 	moveql	#1, %d1
 	lsll	%d2, %d1		/* 2 ^ exponent */
 	addl	%d1, %d0		/* Total size of SDRAM in d0 */
 4:
 .endm

 #else
 #error "ERROR: I don't know how to probe your boards memory size?"
 #endif

 /*****************************************************************************/

 /*
  *	Boards and platforms can do specific early hardware setup if
  *	they need to. Most don't need this, define away if not required.
  */
 #ifndef PLATFORM_SETUP
 #define	PLATFORM_SETUP
 #endif

 /*****************************************************************************/

 .global	_start
 .global _rambase
 .global _ramvec
 .global	_ramstart
 .global	_ramend
 #if defined(CONFIG_UBOOT)
 .global	_init_sp
 #endif

 /*****************************************************************************/

 .data

 /*
  *	During startup we store away the RAM setup. These are not in the
  *	bss, since their values are determined and written before the bss
  *	has been cleared.
  */
 _rambase:
 .long	0
 _ramvec:
 .long	0
 _ramstart:
 .long	0
 _ramend:
 .long	0
 #if defined(CONFIG_UBOOT)
 _init_sp:
 .long	0
 #endif

 /*****************************************************************************/

 __HEAD

 #ifdef CONFIG_MMU
 _start0:
 	jmp	_start
 .global kernel_pg_dir
 .equ	kernel_pg_dir,_start0
 .equ	.,_start0+0x1000
 #endif

 /*
  *	This is the codes first entry point. This is where it all
  *	begins...
  */

 _start:
 	nop					/* filler */
 	movew	#0x2700, %sr			/* no interrupts */
 	movel	#CACHE_INIT,%d0			/* disable cache */
 	movec	%d0,%CACR
 	nop
 #if defined(CONFIG_UBOOT)
 	movel	%sp,_init_sp			/* save initial stack pointer */
 #endif
 #ifdef CONFIG_MBAR
 	movel	#CONFIG_MBAR+1,%d0		/* configured MBAR address */
 	movec	%d0,%MBAR			/* set it */
 #endif

 	/*
 	 *	Do any platform or board specific setup now. Most boards
 	 *	don't need anything. Those exceptions are define this in
 	 *	their board specific includes.
 	 */
 	PLATFORM_SETUP

 	/*
 	 *	Create basic memory configuration. Set VBR accordingly,
 	 *	and size memory.
 	 */
 	movel	#CONFIG_VECTORBASE,%a7
 	movec   %a7,%VBR			/* set vectors addr */
 	movel	%a7,_ramvec

 	movel	#CONFIG_RAMBASE,%a7		/* mark the base of RAM */
 	movel	%a7,_rambase

 	GET_MEM_SIZE				/* macro code determines size */
 	addl	%a7,%d0
 	movel	%d0,_ramend			/* set end ram addr */

 	/*
 	 *	Now that we know what the memory is, lets enable cache
 	 *	and get things moving. This is Coldfire CPU specific. Not
 	 *	all version cores have identical cache register setup. But
 	 *	it is very similar. Define the exact settings in the headers
 	 *	then the code here is the same for all.
 	 */
 	movel	#ACR0_MODE,%d0			/* set RAM region for caching */
 	movec	%d0,%ACR0
 	movel	#ACR1_MODE,%d0			/* anything else to cache? */
 	movec	%d0,%ACR1
 #ifdef ACR2_MODE
 	movel	#ACR2_MODE,%d0
 	movec	%d0,%ACR2
 	movel	#ACR3_MODE,%d0
 	movec	%d0,%ACR3
 #endif
 	movel	#CACHE_MODE,%d0			/* enable cache */
 	movec	%d0,%CACR
 	nop

 #ifdef CONFIG_MMU
 	/*
 	 *	Identity mapping for the kernel region.
 	 */
 	movel	#(MMUBASE+1),%d0		/* enable MMUBAR registers */
 	movec	%d0,%MMUBAR
 	movel	#MMUOR_CA,%d0			/* clear TLB entries */
 	movel	%d0,MMUOR
 	movel	#0,%d0				/* set ASID to 0 */
 	movec	%d0,%asid

 	movel	#MMUCR_EN,%d0			/* Enable the identity map */
 	movel	%d0,MMUCR
 	nop					/* sync i-pipeline */

 	movel	#_vstart,%a0			/* jump to "virtual" space */
 	jmp	%a0@
 _vstart:
 #endif /* CONFIG_MMU */

 #ifdef CONFIG_ROMFS_FS
 	/*
 	 *	Move ROM filesystem above bss :-)
 	 */
 	lea	__bss_start,%a0			/* get start of bss */
 	lea	__bss_stop,%a1			/* set up destination  */
 	movel	%a0,%a2				/* copy of bss start */

 	movel	8(%a0),%d0			/* get size of ROMFS */
 	addql	#8,%d0				/* allow for rounding */
 	andl	#0xfffffffc, %d0		/* whole words */

 	addl	%d0,%a0				/* copy from end */
 	addl	%d0,%a1				/* copy from end */
 	movel	%a1,_ramstart			/* set start of ram */

 _copy_romfs:
 	movel	-(%a0),%d0			/* copy dword */
 	movel	%d0,-(%a1)
 	cmpl	%a0,%a2				/* check if at end */
 	bne	_copy_romfs

 #else /* CONFIG_ROMFS_FS */
 	lea	__bss_stop,%a1
 	movel	%a1,_ramstart
 #endif /* CONFIG_ROMFS_FS */


 	/*
 	 *	Zero out the bss region.
 	 */
 	lea	__bss_start,%a0			/* get start of bss */
 	lea	__bss_stop,%a1			/* get end of bss */
 	clrl	%d0				/* set value */
 _clear_bss:
 	movel	%d0,(%a0)+			/* clear each word */
 	cmpl	%a0,%a1				/* check if at end */
 	bne	_clear_bss

 	/*
 	 *	Load the current task pointer and stack.
 	 */
 	lea	init_thread_union,%a0
 	lea	THREAD_SIZE(%a0),%sp

 #ifdef CONFIG_MMU
 .global m68k_cputype
 .global m68k_mmutype
 .global m68k_fputype
 .global m68k_machtype
 	movel	#CPU_COLDFIRE,%d0
 	movel	%d0,m68k_cputype		/* Mark us as a ColdFire */
 	movel	#MMU_COLDFIRE,%d0
 	movel	%d0,m68k_mmutype
 	movel	#FPU_COLDFIRE,%d0
 	movel	%d0,m68k_fputype
 	movel	#MACH_M54XX,%d0
 	movel	%d0,m68k_machtype		/* Mark us as a 54xx machine */
 	lea	init_task,%a2			/* Set "current" init task */
 #endif

 	/*
 	 *	Assember start up done, start code proper.
 	 */
 	jsr	start_kernel			/* start Linux kernel */

 _exit:
 	jmp	_exit				/* should never get here */

 /*****************************************************************************/
	/*****************************************************************************/

	/*
	* head.S -- common startup code for ColdFire CPUs.
	*
	* (C) Copyright 1999-2011, Greg Ungerer <gerg@snapgear.com>.
	*/

	/*****************************************************************************/

	#include <linux/linkage.h>
	#include <linux/init.h>
	#include <asm/asm-offsets.h>
	#include <asm/coldfire.h>
	#include <asm/mcfsim.h>
	#include <asm/mcfmmu.h>
	#include <asm/thread_info.h>

	/*****************************************************************************/

	/*
	* If we don't have a fixed memory size, then lets build in code
	* to auto detect the DRAM size. Obviously this is the preferred
	* method, and should work for most boards. It won't work for those
	* that do not have their RAM starting at address 0, and it only
	* works on SDRAM (not boards fitted with SRAM).
	*/
	#if CONFIG_RAMSIZE != 0
	.macro GET_MEM_SIZE
	movel #CONFIG_RAMSIZE,%d0 /* hard coded memory size */
	.endm

	#elif defined(CONFIG_M5206) \|\| defined(CONFIG_M5206e) \|\| \
	defined(CONFIG_M5249) \|\| defined(CONFIG_M525x) \|\| \
	defined(CONFIG_M527x) \|\| defined(CONFIG_M528x) \|\| \
	defined(CONFIG_M5307) \|\| defined(CONFIG_M5407)
	/*
	* Not all these devices have exactly the same DRAM controller,
	* but the DCMR register is virtually identical - give or take
	* a couple of bits. The only exception is the 5272 devices, their
	* DRAM controller is quite different.
	*/
	.macro GET_MEM_SIZE
	movel MCFSIM_DMR0,%d0 /* get mask for 1st bank */
	btst #0,%d0 /* check if region enabled */
	beq 1f
	andl #0xfffc0000,%d0
	beq 1f
	addl #0x00040000,%d0 /* convert mask to size */
	1:
	movel MCFSIM_DMR1,%d1 /* get mask for 2nd bank */
	btst #0,%d1 /* check if region enabled */
	beq 2f
	andl #0xfffc0000,%d1
	beq 2f
	addl #0x00040000,%d1
	addl %d1,%d0 /* total mem size in d0 */
	2:
	.endm

	#elif defined(CONFIG_M5272)
	.macro GET_MEM_SIZE
	movel MCFSIM_CSOR7,%d0 /* get SDRAM address mask */
	andil #0xfffff000,%d0 /* mask out chip select options */
	negl %d0 /* negate bits */
	.endm

	#elif defined(CONFIG_M520x)
	.macro GET_MEM_SIZE
	clrl %d0
	movel MCFSIM_SDCS0, %d2 /* Get SDRAM chip select 0 config */
	andl #0x1f, %d2 /* Get only the chip select size */
	beq 3f /* Check if it is enabled */
	addql #1, %d2 /* Form exponent */
	moveql #1, %d0
	lsll %d2, %d0 /* 2 ^ exponent */
	3:
	movel MCFSIM_SDCS1, %d2 /* Get SDRAM chip select 1 config */
	andl #0x1f, %d2 /* Get only the chip select size */
	beq 4f /* Check if it is enabled */
	addql #1, %d2 /* Form exponent */
	moveql #1, %d1
	lsll %d2, %d1 /* 2 ^ exponent */
	addl %d1, %d0 /* Total size of SDRAM in d0 */
	4:
	.endm

	#else
	#error "ERROR: I don't know how to probe your boards memory size?"
	#endif

	/*****************************************************************************/

	/*
	* Boards and platforms can do specific early hardware setup if
	* they need to. Most don't need this, define away if not required.
	*/
	#ifndef PLATFORM_SETUP
	#define PLATFORM_SETUP
	#endif

	/*****************************************************************************/

	.global _start
	.global _rambase
	.global _ramvec
	.global _ramstart
	.global _ramend
	#if defined(CONFIG_UBOOT)
	.global _init_sp
	#endif

	/*****************************************************************************/

	.data

	/*
	* During startup we store away the RAM setup. These are not in the
	* bss, since their values are determined and written before the bss
	* has been cleared.
	*/
	_rambase:
	.long 0
	_ramvec:
	.long 0
	_ramstart:
	.long 0
	_ramend:
	.long 0
	#if defined(CONFIG_UBOOT)
	_init_sp:
	.long 0
	#endif

	/*****************************************************************************/

	__HEAD

	#ifdef CONFIG_MMU
	_start0:
	jmp _start
	.global kernel_pg_dir
	.equ kernel_pg_dir,_start0
	.equ .,_start0+0x1000
	#endif

	/*
	* This is the codes first entry point. This is where it all
	* begins...
	*/

	_start:
	nop /* filler */
	movew #0x2700, %sr /* no interrupts */
	movel #CACHE_INIT,%d0 /* disable cache */
	movec %d0,%CACR
	nop
	#if defined(CONFIG_UBOOT)
	movel %sp,_init_sp /* save initial stack pointer */
	#endif
	#ifdef CONFIG_MBAR
	movel #CONFIG_MBAR+1,%d0 /* configured MBAR address */
	movec %d0,%MBAR /* set it */
	#endif

	/*
	* Do any platform or board specific setup now. Most boards
	* don't need anything. Those exceptions are define this in
	* their board specific includes.
	*/
	PLATFORM_SETUP

	/*
	* Create basic memory configuration. Set VBR accordingly,
	* and size memory.
	*/
	movel #CONFIG_VECTORBASE,%a7
	movec %a7,%VBR /* set vectors addr */
	movel %a7,_ramvec

	movel #CONFIG_RAMBASE,%a7 /* mark the base of RAM */
	movel %a7,_rambase

	GET_MEM_SIZE /* macro code determines size */
	addl %a7,%d0
	movel %d0,_ramend /* set end ram addr */

	/*
	* Now that we know what the memory is, lets enable cache
	* and get things moving. This is Coldfire CPU specific. Not
	* all version cores have identical cache register setup. But
	* it is very similar. Define the exact settings in the headers
	* then the code here is the same for all.
	*/
	movel #ACR0_MODE,%d0 /* set RAM region for caching */
	movec %d0,%ACR0
	movel #ACR1_MODE,%d0 /* anything else to cache? */
	movec %d0,%ACR1
	#ifdef ACR2_MODE
	movel #ACR2_MODE,%d0
	movec %d0,%ACR2
	movel #ACR3_MODE,%d0
	movec %d0,%ACR3
	#endif
	movel #CACHE_MODE,%d0 /* enable cache */
	movec %d0,%CACR
	nop

	#ifdef CONFIG_MMU
	/*
	* Identity mapping for the kernel region.
	*/
	movel #(MMUBASE+1),%d0 /* enable MMUBAR registers */
	movec %d0,%MMUBAR
	movel #MMUOR_CA,%d0 /* clear TLB entries */
	movel %d0,MMUOR
	movel #0,%d0 /* set ASID to 0 */
	movec %d0,%asid

	movel #MMUCR_EN,%d0 /* Enable the identity map */
	movel %d0,MMUCR
	nop /* sync i-pipeline */

	movel #_vstart,%a0 /* jump to "virtual" space */
	jmp %a0@
	_vstart:
	#endif /* CONFIG_MMU */

	#ifdef CONFIG_ROMFS_FS
	/*
	* Move ROM filesystem above bss :-)
	*/
	lea __bss_start,%a0 /* get start of bss */
	lea __bss_stop,%a1 /* set up destination */
	movel %a0,%a2 /* copy of bss start */

	movel 8(%a0),%d0 /* get size of ROMFS */
	addql #8,%d0 /* allow for rounding */
	andl #0xfffffffc, %d0 /* whole words */

	addl %d0,%a0 /* copy from end */
	addl %d0,%a1 /* copy from end */
	movel %a1,_ramstart /* set start of ram */

	_copy_romfs:
	movel -(%a0),%d0 /* copy dword */
	movel %d0,-(%a1)
	cmpl %a0,%a2 /* check if at end */
	bne _copy_romfs

	#else /* CONFIG_ROMFS_FS */
	lea __bss_stop,%a1
	movel %a1,_ramstart
	#endif /* CONFIG_ROMFS_FS */


	/*
	* Zero out the bss region.
	*/
	lea __bss_start,%a0 /* get start of bss */
	lea __bss_stop,%a1 /* get end of bss */
	clrl %d0 /* set value */
	_clear_bss:
	movel %d0,(%a0)+ /* clear each word */
	cmpl %a0,%a1 /* check if at end */
	bne _clear_bss

	/*
	* Load the current task pointer and stack.
	*/
	lea init_thread_union,%a0
	lea THREAD_SIZE(%a0),%sp

	#ifdef CONFIG_MMU
	.global m68k_cputype
	.global m68k_mmutype
	.global m68k_fputype
	.global m68k_machtype
	movel #CPU_COLDFIRE,%d0
	movel %d0,m68k_cputype /* Mark us as a ColdFire */
	movel #MMU_COLDFIRE,%d0
	movel %d0,m68k_mmutype
	movel #FPU_COLDFIRE,%d0
	movel %d0,m68k_fputype
	movel #MACH_M54XX,%d0
	movel %d0,m68k_machtype /* Mark us as a 54xx machine */
	lea init_task,%a2 /* Set "current" init task */
	#endif

	/*
	* Assember start up done, start code proper.
	*/
	jsr start_kernel /* start Linux kernel */

	_exit:
	jmp _exit /* should never get here */

	/*****************************************************************************/