PEX_UNC_ERR_STAT
CSR_PCI_WRITE_4(sc, PEX_UNC_ERR_STAT, 0xffffffff);
val = CSR_PCI_READ_4(sc, PEX_UNC_ERR_STAT);
v32 = CSR_PCI_READ_4(sc, PEX_UNC_ERR_STAT);
CSR_PCI_WRITE_4(sc, PEX_UNC_ERR_STAT, 0xffffffff);