MIO_EMM_SWITCH
emm_switch = readq(host->base + MIO_EMM_SWITCH(host));
writeq(emm_switch, host->base + MIO_EMM_SWITCH(host));
writeq(emm_switch, host->base + MIO_EMM_SWITCH(host));
emm_switch = readq(slot->host->base + MIO_EMM_SWITCH(host));
old_slot->cached_switch = readq(host->base + MIO_EMM_SWITCH(host));