KEMPLD_MUTEX_KEY
while (ioread8(pld->io_index) & KEMPLD_MUTEX_KEY)
if (!(index_reg & KEMPLD_MUTEX_KEY)) {
iowrite8(KEMPLD_MUTEX_KEY, pld->io_index);
iowrite8(KEMPLD_MUTEX_KEY, pld->io_index);
iowrite8(KEMPLD_MUTEX_KEY, pld->io_index);