S3C2440 2440init.s分析第一篇（二）

;這里介紹一下計算公式

;//Fpllo=(m*Fin)/(p*2^s)

;//m=MDIV+8,p=PDIV+2,s=SDIV

;The proper range of P and M: 1<=P<=62, 1<=M<=248

;Fpllo必須大于20Mhz小于66Mhz

;Fpllo*2^s必須小于170Mhz

;如下面的PLLCON設定中的M_DIV P_DIV S_DIV是取自option.h中

;#elif (MCLK==40000000)

;#define PLL_M (0x48)

;#define PLL_P (0x3)

;#define PLL_S (0x2)

;所以m=MDIV+8=80,p=PDIV+2=5,s=SDIV=2

;硬件使用晶振為10Mhz,即Fin=10Mhz

;Fpllo=80*10/5*2^2=40Mhz

;To reduce PLL lock time, adjust the LOCKTIME register.

ldr r0,=LOCKTIME

ldr r1,=0xffffff

str r1,[r0]

;//設置PLL的重置延遲

[ PLL_ON_START

; Added for confirm clock divide. for 2440.

; Setting value Fclk:Hclk:Pclk

ldr r0,=CLKDIVN

ldr r1,=CLKDIV_VAL ; 0=1:1:1, 1=1:1:2, 2=1:2:2, 3=1:2:4, 4=1:4:4, 5=1:4:8, 6=1:3:3, 7=1:3:6.

str r1,][r0] ;//數(shù)據(jù)表示分頻數(shù)

;//Configure UPLL Fin=12.0MHz UFout=48MHz

ldr r0,=UPLLCON

ldr r1,=((U_MDIV<<12)+(U_PDIV<<4)+U_SDIV) ;//USB PLL CONFIG

str r1,[r0]

nop ;// Caution: After UPLL setting, at least 7-clocks delay must be inserted for setting hardware be completed.

nop

nop

nop

nop

nop

nop

;//Configure MPLL Fin=12.0MHz MFout=304.8MHz

ldr r0,=MPLLCON

ldr r1,=((M_MDIV<<12)+(M_PDIV<<4)+M_SDIV)

str r1,[r0]

]

;//Check if the boot is caused by the wake-up from SLEEP mode.

ldr r1,=GSTATUS2

ldr r0,[r1]

tst r0,#0x2 ;test if bit[1] is 1 or 0 0->C=1

; 1->C=0

;In case of the wake-up from SLEEP mode, go to SLEEP_WAKEUP handler.

bne WAKEUP_SLEEP ;C=0,jump

EXPORT StartPointAfterSleepWakeUp

StartPointAfterSleepWakeUp

;//3.置存儲相關寄存器的程序

;這是設置SDRAM,flash ROM 存儲器連接和工作時序的程序,片選定義的程序

;SMRDATA map在下面的程序中定義

;SMRDATA中涉及的值請參考memcfg.s程序

;具體寄存器各位含義請參考s3c44b0 spec

;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

;//set memory registers

;//4.初始化各模式下的棧指針

;Initialize stacks

bl InitStacks

;//5.設置缺省中斷處理函數(shù)

; Setup IRQ handler

ldr r0,=HandleIRQ ;This routine is needed

ldr r1,=IsrIRQ ;if there isnt subs pc,lr,#4 at 0x18, 0x1c

str r1,[r0]

;//initialize the IRQ 將普通中斷判斷程序的入口地址給HandleIRQ

;//6.將數(shù)據(jù)段拷貝到ram中 將零初始化數(shù)據(jù)段清零 跳入C語言的main函數(shù)執(zhí)行到這步結束bootloader初步引導結束

;If main() is used, the variable initialization will be done in __main().

[ :LNOT:USE_MAIN ;initialized {FALSE}

;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 just for debug??????????????????????????

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 ;if thumbcode={false} bl main

bl Main ;Dont use main() because ......

b .

]

;//if thumbcod={ture}

[ THUMBCODE ;for start-up code for Thumb mode

orr lr,pc,#1

bx lr

CODE16

bl Main ;Dont use main() because ......

b .

CODE32

]

;function initializing stacks

InitStacks

;Dont 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 ; UndefStack=0x33FF_5C00

orr r1,r0,#ABORTMODE|NOINT

msr cpsr_cxsf,r1 ;AbortMode

ldr sp,=AbortStack ; AbortStack=0x33FF_6000

orr r1,r0,#IRQMODE|NOINT

msr cpsr_cxsf,r1 ;IRQMode

ldr sp,=IRQStack ; IRQStack=0x33FF_7000

orr r1,r0,#FIQMODE|NOINT

msr cpsr_cxsf,r1 ;FIQMode

ldr sp,=FIQStack ; FIQStack=0x33FF_8000

bic r0,r0,#MODEMASK|NOINT

orr r1,r0,#SVCMODE

msr cpsr_cxsf,r1 ;SVCMode

ldr sp,=SVCStack ; SVCStack=0x33FF_5800

;USER mode has not be initialized.

;//為什么不用初始化user的stacks，系統(tǒng)剛啟動的時候運行在哪個模式下？？？？？？？？？？？？？？？？？？？

mov pc,lr

;The LR register wont be valid if the current mode is not SVC mode.？？？？？？？？？？？？？

;//系統(tǒng)一開始運行就是SVCmode？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？

;=====================================================================

; Clock division test

; Assemble code, because VSYNC time is very short

;=====================================================================

EXPORT CLKDIV124

EXPORT CLKDIV144

CLKDIV124

ldr r0, = CLKDIVN

ldr r1, = 0x3 ; 0x3 = 1:2:4

str r1, [r0]

; wait until clock is stable

nop

nop

nop

nop

nop

ldr r0, = REFRESH

ldr r1, [r0]

bic r1, r1, #0xff

bic r1, r1, #(0x7<<8)

orr r1, r1, #0x470 ; REFCNT135

str r1, [r0]

nop

nop

nop

nop

nop

mov pc, lr

CLKDIV144

ldr r0, = CLKDIVN

ldr r1, = 0x4 ; 0x4 = 1:4:4

str r1, [r0]

; wait until clock is stable

nop

nop

nop

nop

nop

ldr r0, = REFRESH

ldr r1, [r0]

bic r1, r1, #0xff

bic r1, r1, #(0x7<<8)

orr r1, r1, #0x630 ; REFCNT675 - 1520

str r1, [r0]

nop

nop

nop

nop

nop

mov pc, lr

;存儲器控制寄存器的定義區(qū)

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 CL=3clk

ALIGN

AREA RamData, DATA, READWRITE

^ _ISR_STARTADDRESS ; _ISR_STARTADDRESS=0x33FF_FF00

HandleReset # 4

HandleUndef # 4

HandleSWI # 4

HandlePabort # 4

HandleDabort # 4

HandleReserved # 4

HandleIRQ # 4

HandleFIQ # 4

;Dont use the label IntVectorTable,

;The value of IntVectorTable is different with the address you think it may be.

;IntVectorTable

;@0x33FF_FF20

HandleEINT0 # 4

HandleEINT1 # 4

HandleEINT2 # 4

HandleEINT3 # 4

HandleEINT4_7 # 4

HandleEINT8_23 # 4

HandleCAM # 4 ; Added for 2440.

HandleBATFLT # 4

HandleTICK # 4

HandleWDT # 4

HandleTIMER0 # 4

HandleTIMER1 # 4

HandleTIMER2 # 4

HandleTIMER3 # 4

HandleTIMER4 # 4

HandleUART2 # 4

;@0x33FF_FF60

HandleLCD # 4

HandleDMA0 # 4

HandleDMA1 # 4

HandleDMA2 # 4

HandleDMA3 # 4

HandleMMC # 4

HandleSPI0 # 4

HandleUART1 # 4

HandleNFCON # 4 ; Added for 2440.

HandleUSBD # 4

HandleUSBH # 4

HandleIIC # 4

HandleUART0 # 4

HandleSPI1 # 4

HandleRTC # 4

HandleADC # 4

;@0x33FF_FFA0

END