PL011_HWREV_MASK
switch (pi->pi_periphid & (PL011_DESIGNER_MASK | PL011_HWREV_MASK)) {
case PL011_DESIGNER_ARM | __SHIFTIN(0, PL011_HWREV_MASK):
case PL011_DESIGNER_ARM | __SHIFTIN(1, PL011_HWREV_MASK):
case PL011_DESIGNER_ARM | __SHIFTIN(2, PL011_HWREV_MASK):