NIG_REG_P0_TX_ARB_CREDIT_UPPER_BOUND_0
REG_WR(sc, NIG_REG_P0_TX_ARB_CREDIT_UPPER_BOUND_0, 0);
NIG_REG_P0_TX_ARB_CREDIT_UPPER_BOUND_0, credit_upper_bound);
REG_WR(sc, NIG_REG_P0_TX_ARB_CREDIT_UPPER_BOUND_0,