2440init.s

s3c2440上的bootloader移植代码

;=========================================
; NAME: 2440INIT.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,Sleep mode
; 2003.03.14:DonGo: Modified for 2440.
;=========================================

	GET option.inc
	GET memcfg.inc
	GET 2440addr.inc

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 ~



 		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$$RO$$Base|	; Base of ROM code
	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	MMU_SetAsyncBusMode
	;IMPORT	MMU_SetFastBusMode	;hzh

	;IMPORT  Main     The main entry of mon program

	AREA    Init,CODE,READONLY

	ENTRY
	
	EXPORT	__ENTRY
__ENTRY
ResetEntry
	;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
    ]



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

	LTORG

;=======
; 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,=0x7fff		;all sub interrupt disable
	str	r1,[r0]

	;tj1017[ {FALSE}
	; rGPFDAT = (rGPFDAT & ~(0xf<<4)) | ((~data & 0xf)<<4);
	; Led_Display
	ldr	r0,=GPFCON
	ldr	r1,=0x0055	;tj1021
	str	r1,[r0]
	ldr	r0,=GPFDAT
	ldr	r1,=0x00
	str	r1,[r0]
	;ldr r1,=0xff
	;str r1,[r0]
	;tj1017]
	END