arch/arm/cpu/armv7/start.S

/*
 * armboot - Startup Code for OMAP3530/ARM Cortex CPU-core
 *
 * Copyright (c) 2004	Texas Instruments <r-woodruff2@ti.com>
 *
 * Copyright (c) 2001	Marius Gröger <mag@sysgo.de>
 * Copyright (c) 2002	Alex Züpke <azu@sysgo.de>
 * Copyright (c) 2002	Gary Jennejohn <garyj@denx.de>
 * Copyright (c) 2003	Richard Woodruff <r-woodruff2@ti.com>
 * Copyright (c) 2003	Kshitij <kshitij@ti.com>
 * Copyright (c) 2006-2008 Syed Mohammed Khasim <x0khasim@ti.com>
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <asm-offsets.h>
#include <config.h>
#include <version.h>
#include <asm/system.h>
#include <linux/linkage.h>

.globl _start
_start: b	reset
	ldr	pc, _undefined_instruction
	ldr	pc, _software_interrupt
	ldr	pc, _prefetch_abort
	ldr	pc, _data_abort
	ldr	pc, _not_used
	ldr	pc, _irq
	ldr	pc, _fiq
#ifdef CONFIG_SPL_BUILD
_undefined_instruction: .word _undefined_instruction
_software_interrupt:	.word _software_interrupt
_prefetch_abort:	.word _prefetch_abort
_data_abort:		.word _data_abort
_not_used:		.word _not_used
_irq:			.word _irq
_fiq:			.word _fiq
_pad:			.word 0x12345678 /* now 16*4=64 */
#else
_undefined_instruction: .word undefined_instruction
_software_interrupt:	.word software_interrupt
_prefetch_abort:	.word prefetch_abort
_data_abort:		.word data_abort
_not_used:		.word not_used
_irq:			.word irq
_fiq:			.word fiq
_pad:			.word 0x12345678 /* now 16*4=64 */
#endif	/* CONFIG_SPL_BUILD */

.global _end_vect
_end_vect:

	.balignl 16,0xdeadbeef
/*************************************************************************
 *
 * Startup Code (reset vector)
 *
 * do important init only if we don't start from memory!
 * setup Memory and board specific bits prior to relocation.
 * relocate armboot to ram
 * setup stack
 *
 *************************************************************************/

#ifdef CONFIG_MACH_AVANTA_LP_FPGA
.globl _start_link_val
_start_link_val:
	.word _start
#endif

.globl _TEXT_BASE
_TEXT_BASE:
	.word	CONFIG_SYS_TEXT_BASE

/*
 * These are defined in the board-specific linker script.
 */
.globl _bss_start_ofs
_bss_start_ofs:
	.word __bss_start - _start

.global	_image_copy_end_ofs
_image_copy_end_ofs:
	.word 	__image_copy_end - _start

.globl _bss_end_ofs
_bss_end_ofs:
	.word __bss_end__ - _start

.globl _end_ofs
_end_ofs:
	.word _end - _start

#ifdef CONFIG_USE_IRQ
/* IRQ stack memory (calculated at run-time) */
.globl IRQ_STACK_START
IRQ_STACK_START:
	.word	0x0badc0de

/* IRQ stack memory (calculated at run-time) */
.globl FIQ_STACK_START
FIQ_STACK_START:
	.word 0x0badc0de
#endif

/* IRQ stack memory (calculated at run-time) + 8 bytes */
.globl IRQ_STACK_START_IN
IRQ_STACK_START_IN:
	.word	0x0badc0de

/*
 * the actual reset code
 */

reset:
#ifdef CONFIG_MARVELL
	/* Disable L2 Cache */
	ldr r1, =0x0
	ldr r0, =0xD0008100
	str r1, [r0]

#if defined (MV88F66XX) || defined (MV88F672X)
/* set lower RTC/WTC configurations (01/00) for Avanta-LP & Armada-375
   this WA is relevant only for Z1,Z2,Z3 stepping revisions */

	/* Read revision ID value
	 r0 = (MV_REG_READ(DEV_VERSION_ID_REG) & REVISON_ID_MASK) >> REVISON_ID_OFFS; */
	ldr r0, =0xD001823C
	ldr r1, [r0]
	and r1, r1, #0xF00
	mov r1, r1, lsr #8

	/* Z1=0, Z2=1, Z3=2 */
	cmp r1, #2
	bgt not_z_revision

	/* CPU RAMs */
	ldr r2, =0x00000E01
	ldr r3, =0xD00E8000
	str r2, [r3]

	ldr r1, =0x11111111
	ldr r0, =0xD00EA100
	str r1, [r0]

	/* SCU  RAMs */
	str r2, [r3]

	ldr r1, =0x00000001
	ldr r0, =0xD00EA108
	str r1, [r0]

	/* L2 RAMs */
	str r2, [r3]

	ldr r1, =0x00000111
	ldr r0, =0xD00EA10c
	str r1, [r0]

not_z_revision:

#endif /* (MV88F66XX) || (MV88F672X) */

	/* Disable windows that overlap with 0xF1000000	*/
	/* By default, window #12 overlaps with 0xF1000000 */
	mov  r1, #0
	ldr  r0, =0xD00200B0
	str  r1, [r0]
	/* Set Registers Base address. */
	ldr  r1, =INTER_REGS_BASE
	ldr  r0, =0xD0020080
	str  r1, [r0]

	/* align CP15 SCU (peripheral) base with internal reg base (scanned initially at Sample@Reset) */
#if defined (MV_MSYS)
	/* PJ4: [0:18] - Shift right Register Base before updating CP15 */
	lsr  r1, r1, #13
	mcr  15, 4, r1, c15, c0, 0
#else
	/* Update SCU (peripheral) register Base address with correct INTER_REG_BASE */
	ldr r2, = 0xC000		/* SCU offset = 0xC000 */
	add r1, r1, r2			/* r1 = INTER_REG_BASE + SCU_OFFSET */
	mcr p15, 4, r1, c15, c0, 0 	/* Write SCU base register */
#endif

#ifdef MV88F78X60
/*
@ Initial PJ4B configurations
@ configure Marvell debug R1
*/
#if defined(__BE)
#if defined(CPU_ARMARCH7)
		SETEND BE /* Sets ENDIANSTATE to 1, for big-endian operation */
#else
	/* disable I-Cache */
	.word 0x100f11ee /* mrc 	p15, 0, r0, c1, c0 */
	.word 0x010ac0e3 /* bic     r0, r0, #4096   ; 0x1000 I-Cache Enable bit*/
	.word 0x0700c0e3 /* bic     r0, r0, #7      ; 0x7 MMU disable + Alignment Fault Checking enabled + D-cache disabled*/
	.word 0x020080e3 /* orr     r0, r0, #2      ; 0x2 */
	.word 0x800080e3 /* orr 	r0, r0, #0x80 	; Endianness = big endians*/
	.word 0x100f01ee /* mcr     15, 0, r0, cr1, cr0, {0} */
#endif
	nop;nop;nop;nop;
	nop;nop;nop;nop;
#endif
#endif	/* if MV88F78X60 */
#endif

	bl	save_boot_params
	/*
	 * set the cpu to SVC32 mode
	 */
	mrs	r0, cpsr
	bic	r0, r0, #0x1f
	orr	r0, r0, #0xd3
	msr	cpsr,r0

#if defined(CONFIG_AVANTA_LP_FPGA)
/* Write to CP15:1 - point exception vector to flash (0xffff0000) */
	ldr	r0, =0x00052078
	mcr 	p15, 0, r0, c1, c0, 0
#endif


/*
 * Setup vector:
 * (OMAP4 spl TEXT_BASE is not 32 byte aligned.
 * Continue to use ROM code vector only in OMAP4 spl)
 */
#if !(defined(CONFIG_OMAP44XX) && defined(CONFIG_SPL_BUILD))
	/* Set V=0 in CP15 SCTRL register - for VBAR to point to vector */
	mrc	p15, 0, r0, c1, c0, 0	@ Read CP15 SCTRL Register
	bic	r0, #CR_V		@ V = 0
	mcr	p15, 0, r0, c1, c0, 0	@ Write CP15 SCTRL Register

	/* Set vector address in CP15 VBAR register */
	ldr	r0, =_start
	mcr	p15, 0, r0, c12, c0, 0	@Set VBAR
#endif

	/* the mask ROM code should have PLL and others stable */
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
	bl	cpu_init_cp15
	bl	cpu_init_crit
#endif

#ifdef CONFIG_MACH_AVANTA_LP_FPGA
/*
 * U-Boot on FPGA board runs from flash till U-Boot relocates itself to DRAM
 */
relocate:				/* relocate U-Boot to RAM */
	adr	r0, _start		/* r0 <- current position of code */
	ldr	r1, _start_link_val	/* test if we run from flash or RAM */
	cmp	r0, r1			/* if equal we run from RAM - no relocation needed */
	beq	clear_bss_fpga

	ldr	r2, _start_link_val
	ldr	r3, _end_ofs
	add	r2, r3, r2		/* r2 <- size of armboot */

copy_loop_fpga:
	ldmia	r0!, {r3-r10}		/* copy from source address [r0] */
	stmia	r1!, {r3-r10}		/* copy to   target address [r1] */
	cmp	r1, r2			/* until source end addreee [r2] */
	ble	copy_loop_fpga

clear_bss_fpga:
	ldr	r0, _bss_start_ofs
	ldr	r1, _start_link_val
	add	r0, r0, r1
	ldr	r1, _bss_end_ofs
	ldr	r2, _start_link_val
	add	r1, r1, r2
	mov	r2, #0x0

clbss_l_fpga:
	str	r2, [r0]
	add	r0, r0, #4
	cmp	r0, r1
	ble	clbss_l_fpga
#endif

	bl	_main

/*------------------------------------------------------------------------------*/

#ifndef CONFIG_SPL_BUILD
/*
 * void relocate_code (addr_sp, gd, addr_moni)
 *
 * This "function" does not return, instead it continues in RAM
 * after relocating the monitor code.
 *
 */
ENTRY(relocate_code)
	mov	r4, r0	/* save addr_sp */
	mov	r5, r1	/* save addr of gd */
	mov	r6, r2	/* save addr of destination */

	adr	r0, _start
	cmp	r0, r6
	moveq	r9, #0		/* no relocation. relocation offset(r9) = 0 */
	beq	relocate_done		/* skip relocation */
	mov	r1, r6			/* r1 <- scratch for copy_loop */
	ldr	r3, _image_copy_end_ofs
	add	r2, r0, r3		/* r2 <- source end address	    */

copy_loop:
	ldmia	r0!, {r9-r10}		/* copy from source address [r0]    */
	stmia	r1!, {r9-r10}		/* copy to   target address [r1]    */
	cmp	r0, r2			/* until source end address [r2]    */
	blo	copy_loop

	/*
	 * fix .rel.dyn relocations
	 */
	ldr	r0, _TEXT_BASE		/* r0 <- Text base */
	sub	r9, r6, r0		/* r9 <- relocation offset */
	ldr	r10, _dynsym_start_ofs	/* r10 <- sym table ofs */
	add	r10, r10, r0		/* r10 <- sym table in FLASH */
	ldr	r2, _rel_dyn_start_ofs	/* r2 <- rel dyn start ofs */
	add	r2, r2, r0		/* r2 <- rel dyn start in FLASH */
	ldr	r3, _rel_dyn_end_ofs	/* r3 <- rel dyn end ofs */
	add	r3, r3, r0		/* r3 <- rel dyn end in FLASH */
fixloop:
	ldr	r0, [r2]		/* r0 <- location to fix up, IN FLASH! */
	add	r0, r0, r9		/* r0 <- location to fix up in RAM */
	ldr	r1, [r2, #4]
	and	r7, r1, #0xff
	cmp	r7, #23			/* relative fixup? */
	beq	fixrel
	cmp	r7, #2			/* absolute fixup? */
	beq	fixabs
	/* ignore unknown type of fixup */
	b	fixnext
fixabs:
	/* absolute fix: set location to (offset) symbol value */
	mov	r1, r1, LSR #4		/* r1 <- symbol index in .dynsym */
	add	r1, r10, r1		/* r1 <- address of symbol in table */
	ldr	r1, [r1, #4]		/* r1 <- symbol value */
	add	r1, r1, r9		/* r1 <- relocated sym addr */
	b	fixnext
fixrel:
	/* relative fix: increase location by offset */
	ldr	r1, [r0]
	add	r1, r1, r9
fixnext:
	str	r1, [r0]
	add	r2, r2, #8		/* each rel.dyn entry is 8 bytes */
	cmp	r2, r3
	blo	fixloop

relocate_done:

	bx	lr

_rel_dyn_start_ofs:
	.word __rel_dyn_start - _start
_rel_dyn_end_ofs:
	.word __rel_dyn_end - _start
_dynsym_start_ofs:
	.word __dynsym_start - _start
ENDPROC(relocate_code)

#endif

ENTRY(c_runtime_cpu_setup)
/*
 * If I-cache is enabled invalidate it
 */
#ifndef CONFIG_SYS_ICACHE_OFF
	mcr	p15, 0, r0, c7, c5, 0	@ invalidate icache
	mcr     p15, 0, r0, c7, c10, 4	@ DSB
	mcr     p15, 0, r0, c7, c5, 4	@ ISB
#endif
/*
 * Move vector table
 */
#if !defined(CONFIG_TEGRA20)
	/* Set vector address in CP15 VBAR register */
	ldr     r0, =_start
	add     r0, r0, r9
	mcr     p15, 0, r0, c12, c0, 0  @Set VBAR
#endif /* !Tegra20 */

	bx	lr

ENDPROC(c_runtime_cpu_setup)

/*************************************************************************
 *
 * void save_boot_params(u32 r0, u32 r1, u32 r2, u32 r3)
 *	__attribute__((weak));
 *
 * Stack pointer is not yet initialized at this moment
 * Don't save anything to stack even if compiled with -O0
 *
 *************************************************************************/
ENTRY(save_boot_params)
	bx	lr			@ back to my caller
ENDPROC(save_boot_params)
	.weak	save_boot_params

/*************************************************************************
 *
 * cpu_init_cp15
 *
 * Setup CP15 registers (cache, MMU, TLBs). The I-cache is turned on unless
 * CONFIG_SYS_ICACHE_OFF is defined.
 *
 *************************************************************************/
ENTRY(cpu_init_cp15)
	/*
	 * Invalidate L1 I/D
	 */
	mov	r0, #0			@ set up for MCR
	mcr	p15, 0, r0, c8, c7, 0	@ invalidate TLBs
	mcr	p15, 0, r0, c7, c5, 0	@ invalidate icache
	mcr	p15, 0, r0, c7, c5, 6	@ invalidate BP array
	mcr     p15, 0, r0, c7, c10, 4	@ DSB
	mcr     p15, 0, r0, c7, c5, 4	@ ISB

	/*
	 * disable MMU stuff and caches
	 */
	mrc	p15, 0, r0, c1, c0, 0
	bic	r0, r0, #0x00002000	@ clear bits 13 (--V-)
#if defined(CONFIG_MARVELL) && defined(__BE)
	bic	r0, r0, #0x00000007	@ clear bits  2:0 (B--- -CAM)
#else
	bic	r0, r0, #0x00000087	@ clear bits 7, 2:0 (B--- -CAM)
#endif
	bic	r0, r0, #0x00000007	@ clear bits 2:0 (-CAM)
#if !defined(CONFIG_MARVELL)
	orr	r0, r0, #0x00000002	@ set bit 1 (--A-) Align
#endif
	orr	r0, r0, #0x00000800	@ set bit 11 (Z---) BTB
#ifdef CONFIG_SYS_ICACHE_OFF
	bic	r0, r0, #0x00001000	@ clear bit 12 (I) I-cache
#else
	orr	r0, r0, #0x00001000	@ set bit 12 (I) I-cache
#endif
	mcr	p15, 0, r0, c1, c0, 0
	mov	pc, lr			@ back to my caller
ENDPROC(cpu_init_cp15)

#ifndef CONFIG_SKIP_LOWLEVEL_INIT
/*************************************************************************
 *
 * CPU_init_critical registers
 *
 * setup important registers
 * setup memory timing
 *
 *************************************************************************/
ENTRY(cpu_init_crit)
	/*
	 * Jump to board specific initialization...
	 * The Mask ROM will have already initialized
	 * basic memory. Go here to bump up clock rate and handle
	 * wake up conditions.
	 */
	b	lowlevel_init		@ go setup pll,mux,memory
ENDPROC(cpu_init_crit)
#endif

#ifndef CONFIG_SPL_BUILD
/*
 *************************************************************************
 *
 * Interrupt handling
 *
 *************************************************************************
 */
@
@ IRQ stack frame.
@
#define S_FRAME_SIZE	72

#define S_OLD_R0	68
#define S_PSR		64
#define S_PC		60
#define S_LR		56
#define S_SP		52

#define S_IP		48
#define S_FP		44
#define S_R10		40
#define S_R9		36
#define S_R8		32
#define S_R7		28
#define S_R6		24
#define S_R5		20
#define S_R4		16
#define S_R3		12
#define S_R2		8
#define S_R1		4
#define S_R0		0

#define MODE_SVC 0x13
#define I_BIT	 0x80

/*
 * use bad_save_user_regs for abort/prefetch/undef/swi ...
 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
 */

	.macro	bad_save_user_regs
	sub	sp, sp, #S_FRAME_SIZE		@ carve out a frame on current
						@ user stack
	stmia	sp, {r0 - r12}			@ Save user registers (now in
						@ svc mode) r0-r12
	ldr	r2, IRQ_STACK_START_IN		@ set base 2 words into abort
						@ stack
	ldmia	r2, {r2 - r3}			@ get values for "aborted" pc
						@ and cpsr (into parm regs)
	add	r0, sp, #S_FRAME_SIZE		@ grab pointer to old stack

	add	r5, sp, #S_SP
	mov	r1, lr
	stmia	r5, {r0 - r3}			@ save sp_SVC, lr_SVC, pc, cpsr
	mov	r0, sp				@ save current stack into r0
						@ (param register)
	.endm

	.macro	irq_save_user_regs
	sub	sp, sp, #S_FRAME_SIZE
	stmia	sp, {r0 - r12}			@ Calling r0-r12
	add	r8, sp, #S_PC			@ !! R8 NEEDS to be saved !!
						@ a reserved stack spot would
						@ be good.
	stmdb	r8, {sp, lr}^			@ Calling SP, LR
	str	lr, [r8, #0]			@ Save calling PC
	mrs	r6, spsr
	str	r6, [r8, #4]			@ Save CPSR
	str	r0, [r8, #8]			@ Save OLD_R0
	mov	r0, sp
	.endm

	.macro	irq_restore_user_regs
	ldmia	sp, {r0 - lr}^			@ Calling r0 - lr
	mov	r0, r0
	ldr	lr, [sp, #S_PC]			@ Get PC
	add	sp, sp, #S_FRAME_SIZE
	subs	pc, lr, #4			@ return & move spsr_svc into
						@ cpsr
	.endm

	.macro get_bad_stack
	ldr	r13, IRQ_STACK_START_IN		@ setup our mode stack (enter
						@ in banked mode)

	str	lr, [r13]			@ save caller lr in position 0
						@ of saved stack
	mrs	lr, spsr			@ get the spsr
	str	lr, [r13, #4]			@ save spsr in position 1 of
						@ saved stack

	mov	r13, #MODE_SVC			@ prepare SVC-Mode
	@ msr	spsr_c, r13
	msr	spsr, r13			@ switch modes, make sure
						@ moves will execute
	mov	lr, pc				@ capture return pc
	movs	pc, lr				@ jump to next instruction &
						@ switch modes.
	.endm

	.macro get_bad_stack_swi
	sub	r13, r13, #4			@ space on current stack for
						@ scratch reg.
	str	r0, [r13]			@ save R0's value.
	ldr	r0, IRQ_STACK_START_IN		@ get data regions start
						@ spots for abort stack
	str	lr, [r0]			@ save caller lr in position 0
						@ of saved stack
	mrs	r0, spsr			@ get the spsr
	str	lr, [r0, #4]			@ save spsr in position 1 of
						@ saved stack
	ldr	r0, [r13]			@ restore r0
	add	r13, r13, #4			@ pop stack entry
	.endm

	.macro get_irq_stack			@ setup IRQ stack
	ldr	sp, IRQ_STACK_START
	.endm

	.macro get_fiq_stack			@ setup FIQ stack
	ldr	sp, FIQ_STACK_START
	.endm

/*
 * exception handlers
 */
	.align	5
undefined_instruction:
	get_bad_stack
	bad_save_user_regs
	bl	do_undefined_instruction

	.align	5
software_interrupt:
	get_bad_stack_swi
	bad_save_user_regs
	bl	do_software_interrupt

	.align	5
prefetch_abort:
	get_bad_stack
	bad_save_user_regs
	bl	do_prefetch_abort

	.align	5
data_abort:
	get_bad_stack
	bad_save_user_regs
	bl	do_data_abort

	.align	5
not_used:
	get_bad_stack
	bad_save_user_regs
	bl	do_not_used

#ifdef CONFIG_USE_IRQ

	.align	5
irq:
	get_irq_stack
	irq_save_user_regs
	bl	do_irq
	irq_restore_user_regs

	.align	5
fiq:
	get_fiq_stack
	/* someone ought to write a more effective fiq_save_user_regs */
	irq_save_user_regs
	bl	do_fiq
	irq_restore_user_regs

#else

	.align	5
irq:
	get_bad_stack
	bad_save_user_regs
	bl	do_irq

	.align	5
fiq:
	get_bad_stack
	bad_save_user_regs
	bl	do_fiq

#endif /* CONFIG_USE_IRQ */
#endif /* CONFIG_SPL_BUILD */
	.align 5
.global armv7_mmu_cache_flush
armv7_mmu_cache_flush:
		mrc	p15, 0, r10, c0, c1, 5	@ read ID_MMFR1
		tst	r10, #0xf << 16		@ hierarchical cache (ARMv7)
		mov	r10, #0
		beq	hierarchical
		mcr	p15, 0, r10, c7, c6, 0	@ clean+invalidate D
		b	iflush
hierarchical:
		mcr	p15, 0, r10, c7, c10, 5	@ DMB
		stmfd	sp!, {r0-r7, r9-r11}
		mrc	p15, 1, r0, c0, c0, 1	@ read clidr
		ands	r3, r0, #0x7000000	@ extract loc from clidr
		mov	r3, r3, lsr #23		@ left align loc bit field
		beq	finished		@ if loc is 0, then no need to clean
		mov	r10, #0			@ start clean at cache level 0
loop1:
		add	r2, r10, r10, lsr #1	@ work out 3x current cache level
		mov	r1, r0, lsr r2		@ extract cache type bits from clidr
		and	r1, r1, #7		@ mask of the bits for current cache only
		cmp	r1, #2			@ see what cache we have at this level
		blt	skip			@ skip if no cache, or just i-cache
		mcr	p15, 2, r10, c0, c0, 0	@ select current cache level in cssr
		mcr	p15, 0, r10, c7, c5, 4	@ isb to sych the new cssr&csidr
		mrc	p15, 1, r1, c0, c0, 0	@ read the new csidr
		and	r2, r1, #7		@ extract the length of the cache lines
		add	r2, r2, #4		@ add 4 (line length offset)
		ldr	r4, =0x3ff
		ands	r4, r4, r1, lsr #3	@ find maximum number on the way size
		clz	r5, r4			@ find bit position of way size increment
		ldr	r7, =0x7fff
		ands	r7, r7, r1, lsr #13	@ extract max number of the index size
loop2:
		mov	r9, r4			@ create working copy of max way size
loop3:
		orr	r11, r10, r9, lsl r5	@ factor way and cache number into r11
		orr	r11, r11, r7, lsl r2	@ factor index number into r11
		mcr	p15, 0, r11, c7, c14, 2	@ clean & invalidate by set/way
		subs	r9, r9, #1		@ decrement the way
		bge	loop3
		subs	r7, r7, #1		@ decrement the index
		bge	loop2
skip:
		add	r10, r10, #2		@ increment cache number
		cmp	r3, r10
		bgt	loop1
finished:
		ldmfd	sp!, {r0-r7, r9-r11}
		mov	r10, #0			@ swith back to cache level 0
		mcr	p15, 2, r10, c0, c0, 0	@ select current cache level in cssr
iflush:
		mcr	p15, 0, r10, c7, c10, 4	@ DSB
		mcr	p15, 0, r10, c7, c5, 0	@ invalidate I+BTB
		mcr	p15, 0, r10, c7, c10, 4	@ DSB
		mcr	p15, 0, r10, c7, c5, 4	@ ISB
		mov	pc, lr