SMMU_CB_FSR
smmu_cb_write_4(sc, i, SMMU_CB_FSR, SMMU_CB_FSR_MASK);
reg = smmu_cb_read_4(sc, cbi->cbi_idx, SMMU_CB_FSR);
smmu_cb_write_4(sc, cbi->cbi_idx, SMMU_CB_FSR, reg);