add: card->mount_step = 0; card->result = result;
context: static void __sdcard_dounmount(s32 chn,s32 result){	u32 level;	sdcard_block *card = NULL;	if(chn<EXI_CHANNEL_0 || chn>=EXI_CHANNEL_2) return;	card = &sdcard_map[chn];		_CPU_ISR_Disable(level);	if(card->attached) {		card->attached = 0;		EXI_RegisterEXICallback(chn,NULL);		EXI_Detach(chn);		SYS_CancelAlarm(&card->timeout_svc);	}	_CPU_ISR_Restore(level);}