ARM 베어 메탈 - 부팅 코드 분석

28511 단어
ARM 베어 메탈 - 부팅 코드 분석
먼저 부팅 코드와 Bootloader의 차이를 알아야 한다. 부팅 코드는 CPU가 복원된 후 C 언어의main 함수에 들어가기 전에 실행해야 하는 어셈블리 코드를 말한다.
아래의 코드는 우선 이렇게 합시다. 주석이 없고, 시간 관계상, 저는 우선 응용을 좀 하고 나서 다시 이야기합시다 ^ ^
;=========================================
; NAME: 2410INIT.S
; DESC: C start up codes
;       Configure memory, ISR ,stacks
;	Initialize C-variables
; HISTORY:
; 2002.02.25:kwtark: ver 0.0
; 2002.03.20:purnnamu: Add some functions for testing STOP,POWER_OFF mode
; 2002.04.10:SJS:sub interrupt disable 0x3ff -> 0x7ff 
;=========================================

	GET option.s
	GET memcfg.s
	GET 2410addr.s 

BIT_SELFREFRESH EQU	(1<<22)

;Pre-defined constants
USERMODE    EQU 	0x10
FIQMODE     EQU 	0x11
IRQMODE     EQU 	0x12
SVCMODE     EQU 	0x13
ABORTMODE   EQU 	0x17
UNDEFMODE   EQU 	0x1b
MODEMASK    EQU 	0x1f
NOINT       EQU 	0xc0

;The location of stacks
UserStack   EQU (_STACK_BASEADDRESS-0x3800) ;0x33ff4800 ~ 
SVCStack    EQU (_STACK_BASEADDRESS-0x2800) ;0x33ff5800 ~
UndefStack  EQU (_STACK_BASEADDRESS-0x2400) ;0x33ff5c00 ~
AbortStack  EQU (_STACK_BASEADDRESS-0x2000) ;0x33ff6000 ~
IRQStack    EQU (_STACK_BASEADDRESS-0x1000) ;0x33ff7000 ~
FIQStack    EQU (_STACK_BASEADDRESS-0x0)    ;0x33ff8000 ~ 

;Check if tasm.exe(armasm -16 ...@ADS 1.0) is used.
	GBLL    THUMBCODE
	[ {CONFIG} = 16 
THUMBCODE SETL  {TRUE}
	    CODE32
    	|   
THUMBCODE SETL  {FALSE}
    	]

    	MACRO
	MOV_PC_LR
    	[ THUMBCODE
            bx lr
    	|
            mov	pc,lr
    	]
	MEND

    	MACRO
	MOVEQ_PC_LR
    	[ THUMBCODE
    	    bxeq lr
    	|
            moveq pc,lr
    	] 
	MEND

    	MACRO
$HandlerLabel HANDLER $HandleLabel

$HandlerLabel
	sub	sp,sp,#4        ;decrement sp(to store jump address)
	stmfd	sp!,{r0}        ;PUSH the work register to stack(lr does't push because it return to original address)
	ldr     r0,=$HandleLabel;load the address of HandleXXX to r0
	ldr     r0,[r0]         ;load the contents(service routine start address) of HandleXXX
	str     r0,[sp,#4]      ;store the contents(ISR) of HandleXXX to stack
	ldmfd   sp!,{r0,pc}     ;POP the work register and pc(jump to ISR)
	MEND
	

	IMPORT  |Image$$RO$$Limit|  ; End of ROM code (=start of ROM data)
	IMPORT  |Image$$RW$$Base|   ; Base of RAM to initialise
	IMPORT  |Image$$ZI$$Base|   ; Base and limit of area
	IMPORT  |Image$$ZI$$Limit|  ; to zero initialise
	
	IMPORT  Main    ; The main entry of mon program 
	
	AREA    Init,CODE,READONLY

	ENTRY  

	;1)The code, which converts to Big-endian, should be in little endian code.
	;2)The following little endian code will be compiled in Big-Endian mode. 
	;  The code byte order should be changed as the memory bus width.
	;3)The pseudo instruction,DCD can't be used here because the linker generates error.
	ASSERT	:DEF:ENDIAN_CHANGE
	[ ENDIAN_CHANGE
	    ASSERT  :DEF:ENTRY_BUS_WIDTH
	    [ ENTRY_BUS_WIDTH=32
		b	ChangeBigEndian	    ;DCD 0xea000007 
	    ]
	     
	    [ ENTRY_BUS_WIDTH=16
		andeq	r14,r7,r0,lsl #20   ;DCD 0x0007ea00
	    ]
	    
	    [ ENTRY_BUS_WIDTH=8
		streq	r0,[r0,-r10,ror #1] ;DCD 0x070000ea
            ]
	|
	    b	ResetHandler  
    	]
	b	HandlerUndef	;handler for Undefined mode
	b	HandlerSWI	;handler for SWI interrupt
	b	HandlerPabort	;handler for PAbort
	b	HandlerDabort	;handler for DAbort
	b	.		;reserved
	b	HandlerIRQ	;handler for IRQ interrupt 
	b	HandlerFIQ	;handler for FIQ interrupt

;@0x20
	b	EnterPWDN
ChangeBigEndian
;@0x24
	[ ENTRY_BUS_WIDTH=32
	    DCD	0xee110f10	;0xee110f10 => mrc p15,0,r0,c1,c0,0
	    DCD	0xe3800080	;0xe3800080 => orr r0,r0,#0x80;  //Big-endian
	    DCD	0xee010f10	;0xee010f10 => mcr p15,0,r0,c1,c0,0
	]
	[ ENTRY_BUS_WIDTH=16
	    DCD 0x0f10ee11
	    DCD 0x0080e380	
	    DCD 0x0f10ee01	
	]
	[ ENTRY_BUS_WIDTH=8
	    DCD 0x100f11ee	
	    DCD 0x800080e3	
	    DCD 0x100f01ee	
    	]
	DCD 0xffffffff  ;swinv 0xffffff is similar with NOP and run well in both endian mode. 
	DCD 0xffffffff
	DCD 0xffffffff
	DCD 0xffffffff
	DCD 0xffffffff
	b ResetHandler
	
;Function for entering power down mode
; 1. SDRAM should be in self-refresh mode.
; 2. All interrupt should be maksked for SDRAM/DRAM self-refresh.
; 3. LCD controller should be disabled for SDRAM/DRAM self-refresh.
; 4. The I-cache may have to be turned on. 
; 5. The location of the following code may have not to be changed.

;void EnterPWDN(int CLKCON); 
EnterPWDN			
	mov r2,r0		;r2=rCLKCON
	tst r0,#0x8		;POWER_OFF mode?
	bne ENTER_POWER_OFF

ENTER_STOP	
	ldr r0,=REFRESH		
	ldr r3,[r0]		;r3=rREFRESH	
	mov r1, r3
	orr r1, r1, #BIT_SELFREFRESH
	str r1, [r0]		;Enable SDRAM self-refresh

	mov r1,#16	   	;wait until self-refresh is issued. may not be needed.
0	subs r1,r1,#1
	bne %B0

	ldr r0,=CLKCON		;enter STOP mode.
	str r2,[r0]    

	mov r1,#32
0	subs r1,r1,#1	;1) wait until the STOP mode is in effect.
	bne %B0		;2) Or wait here until the CPU&Peripherals will be turned-off
			;   Entering POWER_OFF mode, only the reset by wake-up is available.

	ldr r0,=REFRESH ;exit from SDRAM self refresh mode.
	str r3,[r0]
	
	MOV_PC_LR

ENTER_POWER_OFF	
	;NOTE.
	;1) rGSTATUS3 should have the return address after wake-up from POWER_OFF mode.
	
	ldr r0,=REFRESH		
	ldr r1,[r0]		;r1=rREFRESH	
	orr r1, r1, #BIT_SELFREFRESH
	str r1, [r0]		;Enable SDRAM self-refresh

	mov r1,#16	   	;Wait until self-refresh is issued,which may not be needed.
0	subs r1,r1,#1
	bne %B0

	ldr 	r1,=MISCCR
	ldr	r0,[r1]
	orr	r0,r0,#(7<<17)  ;Make sure that SCLK0:SCLK->0, SCLK1:SCLK->0, SCKE=L during boot-up 
	str	r0,[r1]

	ldr r0,=CLKCON
	str r2,[r0]    

	b .			;CPU will die here.
	

WAKEUP_POWER_OFF
	;Release SCLKn after wake-up from the POWER_OFF mode.
	ldr 	r1,=MISCCR
	ldr	r0,[r1]
	bic	r0,r0,#(7<<17)  ;SCLK0:0->SCLK, SCLK1:0->SCLK, SCKE:L->H
	str	r0,[r1]
	
	;Set memory control registers
    	ldr	r0,=SMRDATA
	ldr	r1,=BWSCON	;BWSCON Address
	add	r2, r0, #52	;End address of SMRDATA
0       
	ldr	r3, [r0], #4    
	str	r3, [r1], #4    
	cmp	r2, r0		
	bne	%B0

	mov r1,#256
0	subs r1,r1,#1	;1) wait until the SelfRefresh is released.
	bne %B0	
 
	ldr r1,=GSTATUS3 	;GSTATUS3 has the start address just after POWER_OFF wake-up
	ldr r0,[r1]
	mov pc,r0

	LTORG   
HandlerFIQ      HANDLER HandleFIQ
HandlerIRQ      HANDLER HandleIRQ
HandlerUndef    HANDLER HandleUndef
HandlerSWI      HANDLER HandleSWI
HandlerDabort   HANDLER HandleDabort
HandlerPabort   HANDLER HandlePabort

IsrIRQ  
	sub	sp,sp,#4       ;reserved for PC
	stmfd	sp!,{r8-r9}   
	
	ldr	r9,=INTOFFSET
	ldr	r9,[r9]
	ldr	r8,=HandleEINT0
	add	r8,r8,r9,lsl #2
	ldr	r8,[r8]
	str	r8,[sp,#8]
	ldmfd	sp!,{r8-r9,pc}

;=======
; ENTRY  
;=======
ResetHandler
	ldr	r0,=WTCON       ;watch dog disable 
	ldr	r1,=0x0         
	str	r1,[r0]

	ldr	r0,=INTMSK
	ldr	r1,=0xffffffff  ;all interrupt disable
	str	r1,[r0]

	ldr	r0,=INTSUBMSK
	ldr	r1,=0x7ff		;all sub interrupt disable, 2002/04/10
	str	r1,[r0]

	[ {FALSE}
        ; rGPFDAT = (rGPFDAT & ~(0xf<<4)) | ((~data & 0xf)<<4);    
        ; Led_Display
	ldr	r0,=GPFCON
	ldr	r1,=0x5500		
	str	r1,[r0]
	ldr	r0,=GPFDAT
	ldr	r1,=0x10
	str	r1,[r0]
	]

	;To reduce PLL lock time, adjust the LOCKTIME register. 
	ldr	r0,=LOCKTIME
	ldr	r1,=0xffffff
	str	r1,[r0]
        
    	[ PLL_ON_START
	;Configure MPLL
	ldr	r0,=MPLLCON          
	ldr	r1,=((M_MDIV<<12)+(M_PDIV<<4)+M_SDIV)  ;Fin=12MHz,Fout=50MHz
	str	r1,[r0]
	]

	;Check if the boot is caused by the wake-up from POWER_OFF mode.
	ldr	r1,=GSTATUS2
	ldr	r0,[r1]
	tst	r0,#0x2
        ;In case of the wake-up from POWER_OFF mode, go to POWER_OFF_WAKEUP handler. 
	bne	WAKEUP_POWER_OFF

	EXPORT StartPointAfterPowerOffWakeUp
StartPointAfterPowerOffWakeUp

	;Set memory control registers
    	ldr	r0,=SMRDATA
	ldr	r1,=BWSCON	;BWSCON Address
	add	r2, r0, #52	;End address of SMRDATA
0       
	ldr	r3, [r0], #4    
	str	r3, [r1], #4    
	cmp	r2, r0		
	bne	%B0
	
    	;Initialize stacks
	bl	InitStacks
	 
  	; Setup IRQ handler
	ldr	r0,=HandleIRQ       ;This routine is needed
	ldr	r1,=IsrIRQ          ;if there isn't 'subs pc,lr,#4' at 0x18, 0x1c
	str	r1,[r0]

	;Copy and paste RW data/zero initialized data
	ldr	r0, =|Image$$RO$$Limit| ; Get pointer to ROM data
	ldr	r1, =|Image$$RW$$Base|  ; and RAM copy
	ldr	r3, =|Image$$ZI$$Base|  
	
	;Zero init base => top of initialised data
	cmp	r0, r1      ; Check that they are different
	beq	%F2
1       
	cmp	r1, r3      ; Copy init data
	ldrcc	r2, [r0], #4    ;--> LDRCC r2, [r0] + ADD r0, r0, #4         
	strcc	r2, [r1], #4    ;--> STRCC r2, [r1] + ADD r1, r1, #4
	bcc	%B1
2       
	ldr	r1, =|Image$$ZI$$Limit| ; Top of zero init segment
	mov	r2, #0
3       
	cmp	r3, r1      ; Zero init
	strcc	r2, [r3], #4
	bcc	%B3

	

    [ :LNOT:THUMBCODE
    	bl	Main        ;Don't use main() because ......
    	b	.                       
    ]

    [ THUMBCODE         ;for start-up code for Thumb mode
    	orr	lr,pc,#1
    	bx	lr
    	CODE16
    	bl	Main        ;Don't use main() because ......
    	b	.
    	CODE32
    ]


;function initializing stacks
InitStacks
	;Don't use DRAM,such as stmfd,ldmfd......
	;SVCstack is initialized before
	;Under toolkit ver 2.5, 'msr cpsr,r1' can be used instead of 'msr cpsr_cxsf,r1'
	mrs	r0,cpsr
	bic	r0,r0,#MODEMASK
	orr	r1,r0,#UNDEFMODE|NOINT
	msr	cpsr_cxsf,r1		;UndefMode
	ldr	sp,=UndefStack
	
	orr	r1,r0,#ABORTMODE|NOINT
	msr	cpsr_cxsf,r1		;AbortMode
	ldr	sp,=AbortStack

	orr	r1,r0,#IRQMODE|NOINT
	msr	cpsr_cxsf,r1		;IRQMode
	ldr	sp,=IRQStack
    
	orr	r1,r0,#FIQMODE|NOINT
	msr	cpsr_cxsf,r1		;FIQMode
	ldr	sp,=FIQStack

	bic	r0,r0,#MODEMASK|NOINT
	orr	r1,r0,#SVCMODE
	msr	cpsr_cxsf,r1		;SVCMode
	ldr	sp,=SVCStack
	
	;USER mode has not be initialized.
	
	mov	pc,lr 
	;The LR register won't be valid if the current mode is not SVC mode.
	

	LTORG

SMRDATA DATA 
; Memory configuration should be optimized for best performance 
; The following parameter is not optimized.                     
; Memory access cycle parameter strategy
; 1) The memory settings is  safe parameters even at HCLK=75Mhz.
; 2) SDRAM refresh period is for HCLK=75Mhz. 

        DCD (0+(B1_BWSCON<<4)+(B2_BWSCON<<8)+(B3_BWSCON<<12)+(B4_BWSCON<<16)+(B5_BWSCON<<20)+(B6_BWSCON<<24)+(B7_BWSCON<<28))
    	DCD ((B0_Tacs<<13)+(B0_Tcos<<11)+(B0_Tacc<<8)+(B0_Tcoh<<6)+(B0_Tah<<4)+(B0_Tacp<<2)+(B0_PMC))   ;GCS0
    	DCD ((B1_Tacs<<13)+(B1_Tcos<<11)+(B1_Tacc<<8)+(B1_Tcoh<<6)+(B1_Tah<<4)+(B1_Tacp<<2)+(B1_PMC))   ;GCS1 
    	DCD ((B2_Tacs<<13)+(B2_Tcos<<11)+(B2_Tacc<<8)+(B2_Tcoh<<6)+(B2_Tah<<4)+(B2_Tacp<<2)+(B2_PMC))   ;GCS2
    	DCD ((B3_Tacs<<13)+(B3_Tcos<<11)+(B3_Tacc<<8)+(B3_Tcoh<<6)+(B3_Tah<<4)+(B3_Tacp<<2)+(B3_PMC))   ;GCS3
    	DCD ((B4_Tacs<<13)+(B4_Tcos<<11)+(B4_Tacc<<8)+(B4_Tcoh<<6)+(B4_Tah<<4)+(B4_Tacp<<2)+(B4_PMC))   ;GCS4
    	DCD ((B5_Tacs<<13)+(B5_Tcos<<11)+(B5_Tacc<<8)+(B5_Tcoh<<6)+(B5_Tah<<4)+(B5_Tacp<<2)+(B5_PMC))   ;GCS5
    	DCD ((B6_MT<<15)+(B6_Trcd<<2)+(B6_SCAN))    ;GCS6
    	DCD ((B7_MT<<15)+(B7_Trcd<<2)+(B7_SCAN))    ;GCS7
    	DCD ((REFEN<<23)+(TREFMD<<22)+(Trp<<20)+(Trc<<18)+(Tchr<<16)+REFCNT)    



	DCD 0x32            ;SCLK power saving mode, BANKSIZE 128M/128M

    	DCD 0x30            ;MRSR6 CL=3clk
    	DCD 0x30            ;MRSR7
;    	DCD 0x20            ;MRSR6 CL=2clk
;    	DCD 0x20            ;MRSR7

    	ALIGN


    	AREA RamData, DATA, READWRITE

        ^   _ISR_STARTADDRESS
HandleReset 	#   4
HandleUndef 	#   4
HandleSWI   	#   4
HandlePabort    #   4
HandleDabort    #   4
HandleReserved  #   4
HandleIRQ   	#   4
HandleFIQ   	#   4

;Don't use the label 'IntVectorTable',
;The value of IntVectorTable is different with the address you think it may be.
;IntVectorTable
HandleEINT0   	#   4
HandleEINT1   	#   4
HandleEINT2   	#   4
HandleEINT3   	#   4
HandleEINT4_7	#   4
HandleEINT8_23	#   4
HandleRSV6	#   4
HandleBATFLT   	#   4
HandleTICK   	#   4
HandleWDT	#   4
HandleTIMER0 	#   4
HandleTIMER1 	#   4
HandleTIMER2 	#   4
HandleTIMER3 	#   4
HandleTIMER4 	#   4
HandleUART2  	#   4
HandleLCD 	#   4
HandleDMA0	#   4
HandleDMA1	#   4
HandleDMA2	#   4
HandleDMA3	#   4
HandleMMC	#   4
HandleSPI0	#   4
HandleUART1	#   4
HandleRSV24	#   4
HandleUSBD	#   4
HandleUSBH	#   4
HandleIIC   	#   4
HandleUART0 	#   4
HandleSPI1 	#   4
HandleRTC 	#   4
HandleADC 	#   4

        END

위의 이것은 아직 주석이 없습니다. 다음은 이것에 주석이 있는 것을 보십시오. 이것은 실험실에서 산 설비가 가지고 있는 것입니다.
;*---------------------------------------------      ----------------------------------------------------                                      
;*
;*      : 2410INIT.S
;*      :     ARM9     C      ,         ,   ISR  ,       ,
;*                       ,       ,      ,       。
;*      :   S3C2410 ARM9         
;*--------------------------------------------        -------------------------------------------------
;*      : ARM    
;*      : 2005/08/23
;*      : V1.0.1
;*--------------------------------------------        -------------------------------------------------
;*      : ARM    
;*      : 2004/04/20
;*      : v1.0.0
;*-----------------------------------------------------------------------------------------------------------
;*-----------------------------------------------------------------------------------------------------------
;************************************************************************************************************
;*/
	GET option.s
	GET memcfg.s
	GET 2410addr.s

BIT_SELFREFRESH EQU	(1<<22)

;//Pre-defined constants
USERMODE    EQU 	0x10
FIQMODE     EQU 	0x11
IRQMODE     EQU 	0x12
SVCMODE     EQU 	0x13
ABORTMODE   EQU 	0x17
UNDEFMODE   EQU 	0x1b
MODEMASK    EQU 	0x1f
NOINT       EQU 	0xc0

;//The location of stacks
UserStack	EQU	(_STACK_BASEADDRESS-0x3800)			;//0x33ff4800 ~ 
SVCStack    EQU	(_STACK_BASEADDRESS-0x2800) 	    ;//0x33ff5800 ~
UndefStack	EQU	(_STACK_BASEADDRESS-0x2400) 		;//0x33ff5c00 ~
AbortStack	EQU	(_STACK_BASEADDRESS-0x2000) 		;//0x33ff6000 ~
IRQStack    EQU	(_STACK_BASEADDRESS-0x1000)		    ;//0x33ff7000 ~
FIQStack	EQU	(_STACK_BASEADDRESS-0x0)			;//0x33ff8000 ~ 

;//Check if tasm.exe(armasm -16 ...@ADS 1.0) is used.
	GBLL    THUMBCODE
	[ {CONFIG} = 16 
		THUMBCODE SETL  {TRUE}
	    CODE32
    	|   
THUMBCODE SETL  {FALSE}
    	]

    MACRO
	MOV_PC_LR
    	[ THUMBCODE
            bx lr
    	|
            mov	pc,lr
    	]
	MEND

    MACRO
	MOVEQ_PC_LR
    	[ THUMBCODE
    	    bxeq lr
    	|
            moveq pc,lr
    	]
	MEND

    	MACRO
$HandlerLabel HANDLER $HandleLabel

$HandlerLabel
	sub	sp,sp,#4        	;//decrement sp(to store jump address)
	stmfd	sp!,{r0}        ;//PUSH the work register to stack(lr does't push because it return to original address)
	ldr     r0,=$HandleLabel;//load the address of HandleXXX to r0
	ldr     r0,[r0]         ;//load the contents(service routine start address) of HandleXXX
	str     r0,[sp,#4]      ;//store the contents(ISR) of HandleXXX to stack
	ldmfd   sp!,{r0,pc}     ;//POP the work register and pc(jump to ISR)
	MEND
	

	IMPORT  |Image$$RO$$Limit|  ;// End of ROM code (=start of ROM data)
	IMPORT  |Image$$RW$$Base|   ;// Base of RAM to initialise
	IMPORT  |Image$$ZI$$Base|   ;// Base and limit of area
	IMPORT  |Image$$ZI$$Limit|  ;// to zero initialise
	
	;//IMPORT  Main    ;// The main entry of mon program 
	
	AREA    Init,CODE,READONLY

	ENTRY 

	; //1)The code, which converts to Big-endian, should be in little endian code.
	; //2)The following little endian code will be compiled in Big-Endian mode. 
	; //  The code byte order should be changed as the memory bus width.
	; //3)The pseudo instruction,DCD can't be used here because the linker generates error.
	ASSERT	:DEF:ENDIAN_CHANGE
	[ ENDIAN_CHANGE
	    ASSERT  :DEF:ENTRY_BUS_WIDTH
	    [ ENTRY_BUS_WIDTH=32
		b	ChangeBigEndian	    ;//DCD 0xea000007 
	    ]
	    
	    [ ENTRY_BUS_WIDTH=16
		andeq	r14,r7,r0,lsl #20   ;//DCD 0x0007ea00
	    ]
	    
	    [ ENTRY_BUS_WIDTH=8
		streq	r0,[r0,-r10,ror #1] ;//DCD 0x070000ea
            ]
	|
	    b	ResetHandler  
    	]
	b	HandlerUndef	;//handler for Undefined mode
	b	HandlerSWI		;//handler for SWI interrupt
	b	HandlerPabort	;//handler for PAbort
	b	HandlerDabort	;//handler for DAbort
	b	.				;//reserved
	b	HandlerIRQ		;//handler for IRQ interrupt 
	b	HandlerFIQ		;//handler for FIQ interrupt

;//@0x20
	b	EnterPWDN
ChangeBigEndian
;//@0x24
	[ ENTRY_BUS_WIDTH=32
	    DCD	0xee110f10	;//0xee110f10 => mrc p15,0,r0,c1,c0,0
	    DCD	0xe3800080	;//0xe3800080 => orr r0,r0,#0x80;  //Big-endian
	    DCD	0xee010f10	;//0xee010f10 => mcr p15,0,r0,c1,c0,0
	]
	[ ENTRY_BUS_WIDTH=16
	    DCD 0x0f10ee11
	    DCD 0x0080e380	
	    DCD 0x0f10ee01	
	]
	[ ENTRY_BUS_WIDTH=8
	    DCD 0x100f11ee	
	    DCD 0x800080e3	
	    DCD 0x100f01ee	
    	]
	DCD 0xffffffff  ;//swinv 0xffffff is similar with NOP and run well in both endian mode. 
	DCD 0xffffffff
	DCD 0xffffffff
	DCD 0xffffffff
	DCD 0xffffffff
	b ResetHandler
	
;//Function for entering power down mode
;// 1. SDRAM should be in self-refresh mode.
;// 2. All interrupt should be maksked for SDRAM/DRAM self-refresh.
;// 3. LCD controller should be disabled for SDRAM/DRAM self-refresh.
;// 4. The I-cache may have to be turned on. 
;// 5. The location of the following code may have not to be changed.

;//void EnterPWDN(int CLKCON); 
EnterPWDN			
	mov r2,r0					;//r2=rCLKCON
	tst r0,#0x8					;//POWER_OFF mode?
	bne ENTER_POWER_OFF

ENTER_STOP	
	ldr r0,=REFRESH		
	ldr r3,[r0]					;//r3=rREFRESH	
	mov r1, r3
	orr r1, r1, #BIT_SELFREFRESH
	str r1, [r0]				;//Enable SDRAM self-refresh

	mov r1,#16	   				;//wait until self-refresh is issued. may not be needed.
0	subs r1,r1,#1
	bne %B0

	ldr r0,=CLKCON				;//enter STOP mode.
	str r2,[r0]    

	mov r1,#32
0	subs r1,r1,#1				;//1) wait until the STOP mode is in effect.
	bne %B0						;//2) Or wait here until the CPU&Peripherals will be turned-off
								;//   Entering POWER_OFF mode, only the reset by wake-up is available.

	ldr r0,=REFRESH 			;//exit from SDRAM self refresh mode.
	str r3,[r0]
	
	MOV_PC_LR

ENTER_POWER_OFF	
								;//NOTE.
								;//1) rGSTATUS3 should have the return address after wake-up from POWER_OFF mode.
	
	ldr r0,=REFRESH		
	ldr r1,[r0]		;r1=rREFRESH	
	orr r1, r1, #BIT_SELFREFRESH
	str r1, [r0]				;//Enable SDRAM self-refresh

	mov r1,#16	   				;//Wait until self-refresh is issued,which may not be needed.
0	subs r1,r1,#1
	bne %B0

	ldr 	r1,=MISCCR
	ldr	r0,[r1]
	orr	r0,r0,#(7<<17)  		;//Make sure that SCLK0:SCLK->0, SCLK1:SCLK->0, SCKE=L during boot-up 
	str	r0,[r1]

	ldr r0,=CLKCON
	str r2,[r0]    

	b .							;//CPU will die here.
	

WAKEUP_POWER_OFF
								;//Release SCLKn after wake-up from the POWER_OFF mode.
	ldr 	r1,=MISCCR
	ldr	r0,[r1]
	bic	r0,r0,#(7<<17)  		;//SCLK0:0->SCLK, SCLK1:0->SCLK, SCKE:L->H
	str	r0,[r1]
	
								;//Set memory control registers
    ldr	r0,=SMRDATA
	ldr	r1,=BWSCON				;//BWSCON Address
	add	r2, r0, #52				;//End address of SMRDATA
0       
	ldr	r3, [r0], #4    
	str	r3, [r1], #4    
	cmp	r2, r0		
	bne	%B0

	mov r1,#256
0	subs r1,r1,#1				;//1) wait until the SelfRefresh is released.
	bne %B0	

	ldr r1,=GSTATUS3 			;//GSTATUS3 has the start address just after POWER_OFF wake-up
	ldr r0,[r1]
	mov pc,r0

	LTORG   
HandlerFIQ      HANDLER HandleFIQ
HandlerIRQ      HANDLER HandleIRQ
HandlerUndef    HANDLER HandleUndef
HandlerSWI      HANDLER HandleSWI
HandlerDabort   HANDLER HandleDabort
HandlerPabort   HANDLER HandlePabort



IsrIRQ  
	sub	sp,sp,#4       					;//reserved for PC
	stmfd	sp!,{r8-r9}   
	
	ldr	r9,=INTOFFSET
	ldr	r9,[r9]
	ldr	r8,=HandleEINT0
	add	r8,r8,r9,lsl #2
	ldr	r8,[r8]
	str	r8,[sp,#8]
	ldmfd	sp!,{r8-r9,pc}

;//====================================================================
;// ENTRY  
;//===================================================================
ResetHandler
	ldr	r0,=WTCON       ;//watch dog disable 
	ldr	r1,=0x0         
	str	r1,[r0]

	ldr	r0,=INTMSK
	ldr	r1,=0xffffffff  ;//all interrupt disable
	str	r1,[r0]

	ldr	r0,=INTSUBMSK
	ldr	r1,=0x7ff		;//all sub interrupt disable, 2002/04/10
	str	r1,[r0]

	[ {FALSE}
        ;// rGPFDAT = (rGPFDAT & ~(0xf<<4)) | ((~data & 0xf)<<4);    
        ;// Led_Display
	ldr	r0,=GPFCON
	ldr	r1,=0x5500		
	str	r1,[r0]
	ldr	r0,=GPFDAT
	ldr	r1,=0x10
	str	r1,[r0]
	]

	;//To reduce PLL lock time, adjust the LOCKTIME register. 
	ldr	r0,=LOCKTIME
	ldr	r1,=0xffffff
	str	r1,[r0]
        
    	[ PLL_ON_START
	;//Configure MPLL
	ldr	r0,=MPLLCON          
	ldr	r1,=((0xa1<<12)+(3<<4)+0x1)  ;//Fin=12MHz,Fout=50MHz
	str	r1,[r0]
	]

	;//Check if the boot is caused by the wake-up from POWER_OFF mode.
	ldr	r1,=GSTATUS2
	ldr	r0,[r1]
	tst	r0,#0x2
        ;//In case of the wake-up from POWER_OFF mode, go to POWER_OFF_WAKEUP handler. 
	bne	WAKEUP_POWER_OFF

	EXPORT StartPointAfterPowerOffWakeUp
StartPointAfterPowerOffWakeUp

	;//Set memory control registers
    ldr	r0,=SMRDATA
	ldr	r1,=BWSCON	;//BWSCON Address
	add	r2, r0, #52	;//End address of SMRDATA
0       
	ldr	r3, [r0], #4    
	str	r3, [r1], #4    
	cmp	r2, r0		
	bne	%B0
	
    	;//Initialize stacks
	bl	InitStacks
	
  	;// Setup IRQ handler
	ldr	r0,=HandleIRQ       ;//This routine is needed
	ldr	r1,=IsrIRQ          ;//if there isn't 'subs pc,lr,#4' at 0x18, 0x1c
	str	r1,[r0]

	;//Copy and paste RW data/zero initialized data
	ldr	r0, =|Image$$RO$$Limit| ; Get pointer to ROM data
	ldr	r1, =|Image$$RW$$Base|  ; and RAM copy
	ldr	r3, =|Image$$ZI$$Base|  
	
	;//Zero init base => top of initialised data
	cmp	r0, r1      ;// Check that they are different
	beq	%F2
1       
	cmp	r1, r3      ;// Copy init data
	ldrcc	r2, [r0], #4    ;//--> LDRCC r2, [r0] + ADD r0, r0, #4         
	strcc	r2, [r1], #4    ;//--> STRCC r2, [r1] + ADD r1, r1, #4
	bcc	%B1
2       
	ldr	r1, =|Image$$ZI$$Limit| ;// Top of zero init segment
	mov	r2, #0
3       
	cmp	r3, r1      ;// Zero init
	strcc	r2, [r3], #4
	bcc	%B3

;//       
	b UART
UART
    ldr r0, =GPHCON ;//  RxD0,TxD0  
    ldr r1, =0x2afaaa
    str r1, [r0]
    
    ldr r0, =GPHUP
    ldr r1, =0x7ff
    str r1, [r0] ;    // The pull up function is disabled GPH[10:0]


    ldr r0, =UFCON0 ;//  FIFO
    ldr r1, =0x0
    str r1, [r0]
   
    ldr r0, =UMCON0  ;//  AFC
    ldr r1, =0x0
    str r1, [r0]
    
    ldr r0, =ULCON0 ;//      
    ldr r1, =0x3   ; //UART LINE CONFIG      ,     ,     ,8    
    str r1, [r0]
    
    ldr r0, =UCON0 ;//  Uart0   
    ldr r1, =0x245;//RX    ,TX    ,      ,  RX     ,      ,         
    str r1, [r0]
    
    ldr r0, =UBRDIV0 ;//      115200
    ldr r1, =0x1a    ;//int(50700000 / 16 / 115200) - 1 = 26
    str r1, [r0]
    
    mov r1, #100
Delay
    sub r1, r1, #0x1
    bne Delay
    
    ;//   
    ldr r0, =INTMSK
    ldr r1, [r0]
    and r1, r1, #0xefffffff
    str r1, [r0]
    
    MOV R5 , #127 ;//           
    MOV R1 , #0x0 ;//        
LOOP  
   LDR R3 , =UTRSTAT0
   LDR R2 , [R3]
   TST R2 ,#0x04 ;//           
   BEQ LOOP      ;//          ,       LOOP
   LDR R0 , =UTXH0
   
   STR R1 ,[R0] ;//              
   ADD R1, R1, #1
   SUB R5 ,R5, #0x01 ;//     
   CMP R5 ,#0x0
   BNE LOOP
  
LOOP2   B LOOP2 

;    /*
;    pclk    = PCLK;
;    rUFCON0 = 0x0;   //UART channel 0 FIFO control register, FIFO disable
;    rUFCON1 = 0x0;   //UART channel 1 FIFO control register, FIFO disable
;    rUFCON2 = 0x0;   //UART channel 2 FIFO control register, FIFO disable
;    rUMCON0 = 0x0;   //UART chaneel 0 MODEM control register, AFC disable
;    rUMCON1 = 0x0;   //UART chaneel 1 MODEM control register, AFC disable
    
;//UART0
;    rULCON0 = 0x3;   //Line control register : Normal,No parity,1 stop,8 bits
;     //    [10]       [9]     [8]        [7]        [6]      [5]         [4]           [3:2]        [1:0]
;     // Clock Sel,  Tx Int,  Rx Int, Rx Time Out, Rx err, Loop-back, Send break,  Transmit Mode, Receive Mode
;     //     0          1       0    ,     0          1        0           0     ,       01          01
;     //   PCLK       Level    Pulse    Disable    Generate  Normal      Normal        Interrupt or Polling
;    rUCON0  = 0x245;                        // Control register
;//    rUBRDIV0=( (int)(pclk/16./baud) -1 );   //Baud rate divisior register 0
;    rUBRDIV0=( (int)(pclk/16./baud+0.5) -1 );   //Baud rate divisior register 0    
    
;//UART1
;    rULCON1 = 0x3;
;    rUCON1  = 0x245;
;    rUBRDIV1=( (int)(pclk/16./baud) -1 );
;    
;//UART2
;    rULCON2 = 0x3;
;    rUCON2  = 0x245;
;    rUBRDIV2=( (int)(pclk/16./baud) -1 );    
;
;    for(i=0;i<100;i++);
;    
;    */

;//END OF UART HERE


;//function initializing stacks
InitStacks
	;//Don't use DRAM,such as stmfd,ldmfd......
	;//SVCstack is initialized before
	;//Under toolkit ver 2.5, 'msr cpsr,r1' can be used instead of 'msr cpsr_cxsf,r1'
	mrs	r0,cpsr
	bic	r0,r0,#MODEMASK
	orr	r1,r0,#UNDEFMODE|NOINT
	msr	cpsr_cxsf,r1		;//UndefMode
	ldr	sp,=UndefStack
	
	orr	r1,r0,#ABORTMODE|NOINT
	msr	cpsr_cxsf,r1		;//AbortMode
	ldr	sp,=AbortStack

	orr	r1,r0,#IRQMODE|NOINT
	msr	cpsr_cxsf,r1		;//IRQMode
	ldr	sp,=IRQStack
    
	orr	r1,r0,#FIQMODE|NOINT
	msr	cpsr_cxsf,r1		;//FIQMode
	ldr	sp,=FIQStack

	bic	r0,r0,#MODEMASK|NOINT
	orr	r1,r0,#SVCMODE
	msr	cpsr_cxsf,r1		;//SVCMode
	ldr	sp,=SVCStack
	
	;//USER mode has not be initialized.
	
	mov	pc,lr 
	;//The LR register won't be valid if the current mode is not SVC mode.
	

	LTORG
; incbin ..\..\Font\Hzk16.bin
SMRDATA DATA
;// Memory configuration should be optimized for best performance 
;// The following parameter is not optimized.                     
;// Memory access cycle parameter strategy
;// 1) The memory settings is  safe parameters even at HCLK=75Mhz.
;// 2) SDRAM refresh period is for HCLK=75Mhz. 

        DCD (0+(B1_BWSCON<<4)+(B2_BWSCON<<8)+(B3_BWSCON<<12)+(B4_BWSCON<<16)+(B5_BWSCON<<20)+(B6_BWSCON<<24)+(B7_BWSCON<<28))
    	DCD ((B0_Tacs<<13)+(B0_Tcos<<11)+(B0_Tacc<<8)+(B0_Tcoh<<6)+(B0_Tah<<4)+(B0_Tacp<<2)+(B0_PMC))   ;//GCS0
    	DCD ((B1_Tacs<<13)+(B1_Tcos<<11)+(B1_Tacc<<8)+(B1_Tcoh<<6)+(B1_Tah<<4)+(B1_Tacp<<2)+(B1_PMC))   ;//GCS1 
    	DCD ((B2_Tacs<<13)+(B2_Tcos<<11)+(B2_Tacc<<8)+(B2_Tcoh<<6)+(B2_Tah<<4)+(B2_Tacp<<2)+(B2_PMC))   ;//GCS2
    	DCD ((B3_Tacs<<13)+(B3_Tcos<<11)+(B3_Tacc<<8)+(B3_Tcoh<<6)+(B3_Tah<<4)+(B3_Tacp<<2)+(B3_PMC))   ;//GCS3
    	DCD ((B4_Tacs<<13)+(B4_Tcos<<11)+(B4_Tacc<<8)+(B4_Tcoh<<6)+(B4_Tah<<4)+(B4_Tacp<<2)+(B4_PMC))   ;//GCS4
    	DCD ((B5_Tacs<<13)+(B5_Tcos<<11)+(B5_Tacc<<8)+(B5_Tcoh<<6)+(B5_Tah<<4)+(B5_Tacp<<2)+(B5_PMC))   ;//GCS5
    	DCD ((B6_MT<<15)+(B6_Trcd<<2)+(B6_SCAN))    ;//GCS6
    	DCD ((B7_MT<<15)+(B7_Trcd<<2)+(B7_SCAN))    ;//GCS7
    	DCD ((REFEN<<23)+(TREFMD<<22)+(Trp<<20)+(Trc<<18)+(Tchr<<16)+REFCNT)    



		DCD 0x32            ;//SCLK power saving mode, BANKSIZE 128M/128M
    	DCD 0x30            ;//MRSR6 CL=3clk
    	DCD 0x30            ;//MRSR7
;//    	DCD 0x20            ;//MRSR6 CL=2clk
;///   	DCD 0x20            ;//MRSR7

    	ALIGN


    	AREA RamData, DATA, READWRITE

        ^   _ISR_STARTADDRESS
HandleReset 	#   4
HandleUndef 	#   4
HandleSWI   	#   4
HandlePabort    #   4
HandleDabort    #   4
HandleReserved  #   4
HandleIRQ   	#   4
HandleFIQ   	#   4

;//Don't use the label 'IntVectorTable',
;//The value of IntVectorTable is different with the address you think it may be.
;//IntVectorTable
HandleEINT0   	#   4
HandleEINT1   	#   4
HandleEINT2   	#   4
HandleEINT3   	#   4
HandleEINT4_7	#   4
HandleEINT8_23	#   4
HandleRSV6		#   4
HandleBATFLT   	#   4
HandleTICK   	#   4
HandleWDT		#   4
HandleTIMER0 	#   4
HandleTIMER1 	#   4
HandleTIMER2 	#   4
HandleTIMER3 	#   4
HandleTIMER4 	#   4
HandleUART2  	#   4
HandleLCD 		#   4
HandleDMA0		#   4
HandleDMA1		#   4
HandleDMA2		#   4
HandleDMA3		#   4
HandleMMC		#   4
HandleSPI0		#   4
HandleUART1		#   4
HandleRSV24		#   4
HandleUSBD		#   4
HandleUSBH		#   4
HandleIIC   	#   4
HandleUART0 	#   4
HandleSPI1 		#   4
HandleRTC 		#   4
HandleADC 		#   4

        END

  
전재 대상:https://www.cnblogs.com/tao560532/archive/2011/12/13/2285765.html

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