SI_CSR_BPCON
si->si_csr |= SI_CSR_BPCON;
si->si_csr &= ~SI_CSR_BPCON;
if (si->si_csr & SI_CSR_BPCON) {
csr |= SI_CSR_BPCON;
csr &= ~SI_CSR_BPCON;
if (csr & SI_CSR_BPCON) {