learning uboot auto switch to stanbdy system in qca4531 cpu

design:

　　when uboot load kerne failed,we can switch to stanbdy system;

how to realize:

　　when boot fail, we can let uboot env bootKenrelFailCount++, then save to uboot_env partiton.

　   watchdog timeout will trigger cpu reset, when bootKernelFailCount bigger than a fixed number

　　we can realize switch to stanbdy system

reference code:

void bootKernelFailProcess(){

char buf[100]=0;

char *s;

int bootKernelFailCount =0;

s=getenv("bootKernelFailCount");

bootKernelFailCount =++atoi(s);

sprintf(buf,"setenv bootKernelFailCount %d", bootKernelFailCount);

run_command(buf,0);

run_command("saveenv",0);

}

void changeBootslotFunction(){

char buf[100]=0;

int bootslot=0;

s=getenv("bootslot");

bootslot=atoi(s)^1;

sprintf(buf,"setenv bootslot %d",bootslot);

run_command(buf,0);

run_command("saveenv",0);

}

void bootKernelFailCountDetect(){

if( atoi(getenv("bootKernelfailCount ")) > 2 ){

run_command("setenv bootKernelFailCount  0",0);

changeBootslotFunction();

}

}