NIG_REG_P0_TX_ARB_CREDIT_UPPER_BOUND_1
REG_WR(sc, NIG_REG_P0_TX_ARB_CREDIT_UPPER_BOUND_1, 0);
NIG_REG_P0_TX_ARB_CREDIT_UPPER_BOUND_1, credit_upper_bound);
REG_WR(sc, NIG_REG_P0_TX_ARB_CREDIT_UPPER_BOUND_1,