BGE_MI_MODE register accesses. Previously bge(4) used to read
BGE_MI_MODE register to detect whether it needs to disable
autopolling feature or not. Because we don't touch autopolling in
other part of driver there is no reason to read BGE_MI_MODE
register given that we know default value in advance. In order to
achieve the goal, check whether the controller has CPMU(Central
Power Mangement Unit) capability. If controller has CPMU feature,
use 500KHz MII management interface(mdio/mdc) frequency regardless
core clock frequency. Otherwise use default MII clock. While I'm
here, add CPMU register definition.
In bge_miibus_readreg(), rearrange code a bit and remove goto
statement. In bge_miibus_writereg(), make sure to restore
autopolling even if MII write failed. The delay time inserted after
accessing BGE_MI_MODE register increased from 40us to 80us.
The default PHY address is now stored in softc. All PHYs supported
by bge(4) currently uses PHY address 1 but it will be changed when
we add newer controllers. This change will make it easier to change
default PHY address depending on PHY models.
Submitted by: davidch
a813ed787f