第四章之S5PV210内存初始化

1,既然UART可以打印出信息来，那我们可以打印内存中的值。在506行添加如下代码：

     /***UART transmit function by xu ***/
 display_addr_dat:

     ldr r0,[r0]

     ldr r1,=0xE2900020 

     ldr r2,=0x30
     str r2,[r1]     @UTXH0=''

     ldr r2,=0x78
     str r2,[r1]     @UTXH0='x'

     ldr r3,=

 display_loop_count:
     lsr r2,r0,r3    @logical shift right  bit
     and r2,r2,#0xF     

     cmp r2,#      @cmp r2 is mi or pl
     addmi r2,r2,#0x30  @r2 is ----
     addpl r2,r2,#0x37  @r2 is A----F
     str r2,[r1]

     sub r3,r3,#
     cmp r3,#
     bpl display_loop_count

     ldr r2,=0xa
     str r2,[r1]     @UTXH0='\r'

     ldr r2,=0xd
     str r2,[r1]     @UTXH0='\n'

     mov pc, lr

如图：

2，这样我们可以进行测试，在216行，进行添加执行代码，如图：

我们通过手册查询可以得知内存地址oxE000_0000的值为0x43110020。那么重新编译和烧写一下u-boot.bin，看看串口输

出的信息与我们查询的值是否相同。

3，接一下来，我们来自己编写板子的内存初始化代码，可以根据厂家的光盘中裸机代码/src/cdram/memory.S中的代码做相应的

更改。代码如下：

 /*** ddrmem initialze by xu***/
 .globl ddrmem_init
 ddrmem_init:

 #define ELFIN_GPIO_BASE            0xE0200000
 #define APB_DMC_0_BASE            0xF0000000
 #define DMC_CONCONTROL             0x00
 #define DMC_MEMCONTROL             0x04
 #define DMC_MEMCONFIG0             0x08
 #define DMC_DIRECTCMD             0x10
 #define DMC_PRECHCONFIG         0x14
 #define DMC_PHYCONTROL0         0x18
 #define DMC_PHYCONTROL1         0x1C
 #define DMC_RESERVED             0x20
 #define DMC_PWRDNCONFIG         0x28
 #define DMC_TIMINGAREF             0x30
 #define DMC_TIMINGROW             0x34
 #define DMC_TIMINGDATA             0x38
 #define DMC_TIMINGPOWER         0x3C
 #define DMC_PHYSTATUS             0x40
 #define DMC_CHIP0STATUS         0x48
 #define DMC_AREFSTATUS             0x50
 #define DMC_MRSTATUS             0x54
 #define DMC_PHYTEST0             0x58
     //初始化PHY DLL
     ldr r0, =APB_DMC_0_BASE
     //step 2 set PhyControl0.ctrl_start_point PhyControl0.ctrl_inc PhyControl0.ctrl_dll_on bit field to 1
     ldr r1, =0x0010100A
     str r1, [r0,#DMC_PHYCONTROL0]

     //step 3 set PhyControl1.ctrl_shiftc PhyControl1.ctrl_ctrl_offsetc
     ldr r1, =0x00000086
     str r1, [r0,#DMC_PHYCONTROL1]

     //step 4 set PhyControl0.ctrl_start bit-field to 1 DLL on
     ldr r1, =0x0010100B
     str r1, [r0,#DMC_PHYCONTROL0]

 find_lock_val:
     //step 11 loop until DLL is locked
     ldr r1, [r0,#DMC_PHYSTATUS]
     and r2, r1,#0x7
     cmp r2, #0x7
     bne find_lock_val

     //setp 12 Force value looking
     and r1, #0x3fc0
     mov r2, r1, LSL #
     orr r2, r2, #0x100000
     orr r2, r2, #0x1000
     orr r1, r2, #0xB
     str r1, [r0,#DMC_PHYCONTROL0]

     //初始化DMC0
     //step 5 set ConControl
     ldr r1, =0x0FFF1010
     str r1, [r0,#DMC_CONCONTROL]

     //step 6 set MemControl
     ldr r1, =0x00202400
     str r1, [r0,#DMC_MEMCONTROL]

     //step 7 set MemConfig0 512M config,8 banks
     ldr r1, =0x20E00323
     str r1, [r0,#DMC_MEMCONFIG0]

     //step 8/1 set PrechConfig
     ldr r1, =0xFF000000
     str r1, [r0,#DMC_PRECHCONFIG]

     //step 9/1 set TimingAref t_refi=7.5us * 133MHz=1038(0x40E)
     ldr r1, =0x0000040E
     str r1, [r0,#DMC_TIMINGAREF]
     //step 9/2 set TimingRow tRAS=45ns tRC=60ns tRCD=15ns tRP=15ns tRRD=7.5ns tRFC=127.5ns
     ldr r1, =0x11122206
     str r1, [r0,#DMC_TIMINGROW]
     //step 9/3 set TimingData tWTR=7.5ns tWR=15ns tRTP=7.5ns cl=4
     ldr r1, =0x12140000
     str r1, [r0,#DMC_TIMINGDATA]
     //step 9/4 set TimingPower t_mrd>=tMRD=2nCK t_cke<=tCKE=3nCK t_xp>=tXP=2nCK tXSRD=200ns tFAW=35ns
     ldr r1, =0x05DC0343
     str r1, [r0,#DMC_TIMINGPOWER]

     //初始化DDR2 DRAM
     //step 14 lssue a "NOP" for DirectCmd and hold CKE to high level
     ldr r1, =0x07000000
     str r1, [r0,#DMC_DIRECTCMD]

     //step 16 lssue a "PALL" for DirectCmd
     ldr r1, =0x01000000
     str r1, [r0,#DMC_DIRECTCMD]

     //step 17 lssue an "EMRS2" for DirectCmd
     ldr r1, =0x00020000
     str r1, [r0,#DMC_DIRECTCMD]

     //step 18 lssue an "EMRS3" for DirectCmd
     ldr r1, =0x00030000
     str r1, [r0,#DMC_DIRECTCMD]

     //step 19 lssue an "EMRS" for DirectCmd and enable DLLs enable DQS
     ldr r1, =0x00010000
     str r1, [r0,#DMC_DIRECTCMD]

     //step 20 lssue a "MRS" for DirectCmd and reset DLL
     ldr r1, =0x00000542
     str r1, [r0,#DMC_DIRECTCMD]

     //step 21 lssue a "PALL" for DirectCmd
     ldr r1, =0x01000000
     str r1, [r0,#DMC_DIRECTCMD]

     //step 22 lssue two "Auto Refresh" for DirectCmd
     ldr r1, =0x05000000
     str r1,[r0,#DMC_DIRECTCMD]

     ldr r1, =0x05000000
     str r1,[r0,#DMC_DIRECTCMD]

     //step 23 lssue a "MRS" for DirectCmd and without reseting DLL
     ldr r1, =0x00000442
     str r1, [r0,#DMC_DIRECTCMD]

     //step 25 lssue an "EMRS" for DirectCmd  set OCD Calibration Default and exit OCD Calibration
     ldr r1, =0x00010380
     str r1, [r0,#DMC_DIRECTCMD]

     ldr r1, =0x00010000
     str r1, [r0,#DMC_DIRECTCMD]

     //step 27 set ConControl and turn on "auot refresh"
     ldr r1, =0x0FF01030
     str r1, [r0,#DMC_CONCONTROL]

     //step 8/2 set PwrdnConfig
     ldr r1, =0xFFFF00FF
     str r1, [r0,#DMC_PWRDNCONFIG]

     //step 28 IF power down modes is required set MemControl
     ldr r1, =0x00202400
     str r1, [r0,#DMC_MEMCONTROL]

     //putout URAT char "DDR IS OK!"
     ldr r0, =0xE2900020
     ldr r1, =0x44    @UTH='D'
     str r1, [r0]

     ldr r1, =0x44
     str r1, [r0]     @UTH='D'

     ldr r1, =0x52
     str r1, [r0]     @UTH='R'

     ldr r1, =0x20
     str r1, [r0]     @UTH=' '

     ldr r1, =0x49
     str r1, [r0]     @UTH='I'

     ldr r1, =0x53
     str r1, [r0]     @UTH='S'

     ldr r1, =0x20
     str r1, [r0]     @UTH=' '

     ldr r1, =0x4f
     str r1, [r0]     @UTH='O'

     ldr r1, =0x4b
     str r1, [r0]     @UTH='K'

     ldr r1, =0x21
     str r1, [r0]    @UTH='!'

     ldr r1,    =0xa
     str r1,    [r0]     @UTXH0='\r'

     ldr r1,    =0xd
     str r1,    [r0]     @UTXH0='\n'

     mov pc, lr

4，在UART执行代码下面添加内存初始化执行代码220-221行。如图：

5，内存初始化完成，但是我们不知道内存初始化是否正确，这就需要验证。通过内存读取数据代码来进行验证222行-225行。如图所示：

6，然后，进行make,烧写u-boot.bin.然后可以看到串口输出信息中，输出与我们输入相同的内存地址的值