MEMECC_REG_DRAM_CONTROL
rv = memc_reg_read(sc, MEMECC_REG_DRAM_CONTROL);
memc_reg_write(sc, MEMECC_REG_DRAM_CONTROL, rv);
rv = memc_reg_read(sc, MEMECC_REG_DRAM_CONTROL);
memc_reg_write(sc, MEMECC_REG_DRAM_CONTROL, rv);
rv = memc_reg_read(sc, MEMECC_REG_DRAM_CONTROL + off);
memc_reg_write(sc, MEMECC_REG_DRAM_CONTROL + off, rv);