jz2440内存实验（八）

.global _start
_start:
    ldr sp, =4096                            @ 设置堆栈指针
    bl  disable_watch_dog               @ 关闭WATCHDOG，否则CPU会不断重启
    bl  memsetup                             @ 设置存储控制器
    bl  copy_code_to_sdram              @ 复制代码到SDRAM中

    ldr sp, =0x34000000                 @ 重设栈指针，指向SDRAM顶端
    ldr pc, =0x30000000                 @ 跳到SDRAM中继续执行
                                                      @ 这里如何寻找main函数呢？这里提一个问题！

halt_loop:
    b   halt_loop

unsigned long  addr_sdram_stack = 0x34000000;
unsigned long  addr_sdram_base = 0x30000000;
/* WATCHDOG寄存器 */
#define P_WTCON           ((volatile unsigned long *)0x53000000)
/* 存储控制器的寄存器起始地址 */
#define MEM_CTL_BASE    0x48000000
/*
 * 关闭WATCHDOG，否则CPU会不断重启
 */
void disable_watch_dog(void)
{
//      ClearBit(*P_WTCON,5);
//        setNbit(*P_WTCON,1,5,0x0);
      *P_WTCON = 0;
}



void memsetup(void)
{
    /* SDRAM 13个寄存器的值 */
    unsigned long  const    mem_cfg_val[]={ 0x22011110,     //BWSCON
                                            0x00000700,     //BANKCON0
                                            0x00000700,     //BANKCON1
                                            0x00000700,     //BANKCON2
                                            0x00000700,     //BANKCON3 
                                            0x00000700,     //BANKCON4
                                            0x00000700,     //BANKCON5
                                            0x00018005,     //BANKCON6
                                            0x00018005,     //BANKCON7
                                            0x008C07A3,     //REFRESH
                                            0x000000B1,     //BANKSIZE
                                            0x00000030,     //MRSRB6
                                            0x00000030,     //MRSRB7
                                    };
    int     i = 0;
    volatile unsigned long *p = (volatile unsigned long *)MEM_CTL_BASE;
    for(; i < 13; i++)
        p[i] = mem_cfg_val[i];
}


void copy_code_to_sdram(void)
{
    unsigned int *pdwSrc  = (unsigned int *)2048;
    unsigned int *pdwDest = (unsigned int *)addr_sdram_base;

    while (pdwSrc < (unsigned int *)4096) //2k-4k复制
    {
        *pdwDest = *pdwSrc;
        pdwDest++;
        pdwSrc++;
    }
}

#define GPBCON      (*(volatile unsigned long *)0x56000050)
#define GPBDAT      (*(volatile unsigned long *)0x56000054)

int main()
{
    GPBCON = 0x00000100;    // 设置GPB4为输出口, 位[8:7]=0b01
    GPBDAT = 0x00000000;    // GPB4输出0，LED1点亮

    return 0;
}

objs := head.o init.o leds.o
memory.bin : $(objs)
        arm-linux-ld -Tmem.lds -o mem.elf $^
        arm-linux-objcopy -O binary -S mem.elf $@
        arm-linux-objdump -D -m arm mem.elf > mem.dis

#$@--目标文件，$^--所有的依赖文件，$<--第一个依赖文件
%.o:%.c
        arm-linux-gcc -Wall -O2 -c -o $@ $<
%.o:%.S
        arm-linux-gcc -Wall -O2 -c -o $@ $<
clean:
        rm -f *.dis *.bin *.elf *.o ../../pub/*.o

SECTIONS {
  firtst    0x00000000 : { head.o init.o ../../pub/bit.o }
  second    0x30000000 : AT(2048) { leds.o }
  third     :{1.o}
}