MMU_SECDESC;
virtuladdr = 0xB0000000;
physicaladdr = 0x30000000;
while (virtuladdr < 0xB4000000)
{
*(mmu_tlb_base + (virtuladdr >> 20)) = (physicaladdr & 0xFFF00000) |
MMU_SECDESC_WB;
virtuladdr += 0x100000;//右移20位就是1
physicaladdr += 0x100000;//右移20位就是1
}
}
void mmu_init(void)
{
unsigned long ttb = 0x30000000;
__asm__(
"mov r0, #0"
"mcr p15, 0, r0, c7, c7, 0"
"mcr p15, 0, r0, c7, c10, 4"
"mcr p15, 0, r0, c8, c7, 0"
"mov r4, %0"
"mcr p15, 0, r4, c2, c0, 0"
"mvn r0, #0"
"mcr p15, 0, r0, c3, c0, 0"
"mrc p15, 0, r0, c1, c0, 0"
"bic r0, r0, #0x3000"
"bic r0, r0, #0x0300"
"bic r0, r0, #0x0087"
"orr r0, r0, #0x0002"
"orr r0, r0, #0x0004"
"orr r0, r0, #0x1000"
"orr r0, r0, #0x0001"
"mcr p15, 0, r0, c1, c0, 0"
:
: "r" (ttb) );
}
#define GPBCON (*(volatile unsigned long *)0xA0000010) // 物理地址0x56000010
#define GPBDAT (*(volatile unsigned long *)0xA0000014) // 物理地址0x56000014
#define GPB5_out (1<(5*2))
#define GPB6_out (1<(6*2))
#define GPB7_out (1<(7*2))
#define GPB8_out (1<(8*2))
static inline void wait(unsigned long dly)
{
for(; dly > 0; dly--);
}
int main(void)
{
unsigned long i = 0;
// 将LED1-4对应的GPB5/6/7/8四个引脚设为输出
GPBCON = GPB5_out|GPB6_out|GPB7_out|GPB8_out;
while(1){
wait(30000);
GPBDAT = (~(i<5)); // 根据i的值，点亮LED1-4
if(++i == 16)
i = 0;
}
return 0;
}
最后是Makefile
objs := head.o init.o leds.o
mmu.bin : $(objs)
arm-linux-ld -Tmmu.lds -o mmu_elf $^
arm-linux-objcopy -O binary -S mmu_elf $@
arm-linux-objdump -D -m arm mmu_elf > mmu.dis
%.o:%.c
arm-linux-gcc -Wall -O2 -c -o $@ $
%.o:%.S
arm-linux-gcc -Wall -O2 -c -o $@ $
clean:
rm -f mmu.bin mmu_elf mmu.dis *.o
