read_prom_byte
he_dev->prod_id[i] = read_prom_byte(he_dev, PROD_ID + i);
he_dev->media = read_prom_byte(he_dev, MEDIA);
dev->esi[i] = read_prom_byte(he_dev, MAC_ADDR + i);
static u8 read_prom_byte(struct he_dev *he_dev, int addr);