Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r257702, r257745, r257746, r257747, r257751, r257791, r257793,
r257794, r257795, r257992

Teach nexus(4) about Open Firmware (e.g. FDT) on ARM and MIPS, retiring
fdtbus in most cases.

Make OF_nextprop() work correctly for FDT by using the libfdt
fdt_next_property_offset() API.

Do not panic if pmap_mincore() is called.

An addendum: it is possible, though of questionable utility, for a node
to have no properties at all.
Add definition for the Atheros 8021 gigabit PHY.

Consolidate Apple firmware hacks and improve them by switching on the
presence of mac-io devices in the tree, which uniquely identifies Apple
hardware.

Allow OF_decode_addr() to also be able to map resources on big-endian
devices.

Make tsec work with the device tree present on the RB800.

Be more flexible about which compatible strings to accept. This brings up
the PCI Express bus on the RB800 using the firmware device tree.

Rename the "bare" platform "mpc85xx", which is what it actually is, and
add actual platform probing based on PVR.

MFC r257304:
Add support for new Gigabit PHY of RealTek.
I don't have a copy of data sheet so I'm not sure exact PHY model
name. Vendor's web page indicates RTL8251 is latest PHY so I used
the name. This PHY is used with RTL8168G, RTL8168GU and RTL8411B.
Approved by: re (delphij)

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Recognize BCM5725C PHY.

Recognize 5720S PHY and treat it as 5708S PHY.
Unfortunately 5720S uses 5709S PHY id so add a hack to detect 5720S
PHY by checking parent device name. 5720S PHY does not support 2500SX.

Tested by: Geans Pin < geanspin <> broadcom dot com >

Merging of projects/armv6, part 5

- Driver for SMSC LAN95XX and LAN8710A ethernet controllers
- Driver for LAN8710A PHY

Submitted by: Ben Gray, Damjan Marion, Tim Kientzle

More Cicada/Vitesse PHY ids.

Obtained from: Semihalf

Probe the National DP83849, which is a dual-port version of the PHYTER.

Obtained from: NetBSD

- Probe BCM57780.
- In case the parent is bge(4), don't set the Jumbo frame settings unless
the MAC actually is Jumbo capable as otherwise the PHY might not have the
corresponding registers implemented. This is also in line with what the
Linux tg3 driver does.

PR: 165032
Submitted by: Alexander Milanov
Obtained from: OpenBSD
MFC after: 3 days

Sync with NetBSD rev. 1.104

Obtained from: NetBSD

Recognize BCM5720C PHY.

Add detection for the Marvel 88E1149R and treat it just like the
88E1149.

Recognize BCM5719C PHY.

Submitted by: Geans Pin at Broadcom

- Remove attempts to implement setting of BMCR_LOOP/MIIF_NOLOOP
(reporting IFM_LOOP based on BMCR_LOOP is left in place though as
it might provide useful for debugging). For most mii(4) drivers it
was unclear whether the PHYs driven by them actually support
loopback or not. Moreover, typically loopback mode also needs to
be activated on the MAC, which none of the Ethernet drivers using
mii(4) implements. Given that loopback media has no real use (and
obviously hardly had a chance to actually work) besides for driver
development (which just loopback mode should be sufficient for
though, i.e one doesn't necessary need support for loopback media)
support for it is just dropped as both NetBSD and OpenBSD already
did quite some time ago.
- Let mii_phy_add_media() also announce the support of IFM_NONE.
- Restructure the PHY entry points to use a structure of entry points
instead of discrete function pointers, and extend this to include
a "reset" entry point. Make sure any PHY-specific reset routine is
always used, and provide one for lxtphy(4) which disables MII
interrupts (as is done for a few other PHYs we have drivers for).
This includes changing NIC drivers which previously just called the
generic mii_phy_reset() to now actually call the PHY-specific reset
routine, which might be crucial in some cases. While at it, the
redundant checks in these NIC drivers for mii->mii_instance not being
zero before calling the reset routines were removed because as soon
as one PHY driver attaches mii->mii_instance is incremented and we
hardly can end up in their media change callbacks etc if no PHY driver
has attached as mii_attach() would have failed in that case and not
attach a miibus(4) instance.
Consequently, NIC drivers now no longer should call mii_phy_reset()
directly, so it was removed from EXPORT_SYMS.
- Add a mii_phy_dev_attach() as a companion helper to mii_phy_dev_probe().
The purpose of that function is to perform the common steps to attach
a PHY driver instance and to hook it up to the miibus(4) instance and to
optionally also handle the probing, addition and initialization of the
supported media. So all a PHY driver without any special requirements
has to do in its bus attach method is to call mii_phy_dev_attach()
along with PHY-specific MIIF_* flags, a pointer to its PHY functions
and the add_media set to one. All PHY drivers were updated to take
advantage of mii_phy_dev_attach() as appropriate. Along with these
changes the capability mask was added to the mii_softc structure so
PHY drivers taking advantage of mii_phy_dev_attach() but still
handling media on their own do not need to fiddle with the MII attach
arguments anyway.
- Keep track of the PHY offset in the mii_softc structure. This is done
for compatibility with NetBSD/OpenBSD.
- Keep track of the PHY's OUI, model and revision in the mii_softc
structure. Several PHY drivers require this information also after
attaching and previously had to wrap their own softc around mii_softc.
NetBSD/OpenBSD also keep track of the model and revision on their
mii_softc structure. All PHY drivers were updated to take advantage
as appropriate.
- Convert the mebers of the MII data structure to unsigned where
appropriate. This is partly inspired by NetBSD/OpenBSD.
- According to IEEE 802.3-2002 the bits actually have to be reversed
when mapping an OUI to the MII ID registers. All PHY drivers and
miidevs where changed as necessary. Actually this now again allows to
largely share miidevs with NetBSD, which fixed this problem already
9 years ago. Consequently miidevs was synced as far as possible.
- Add MIIF_NOMANPAUSE and mii_phy_flowstatus() calls to drivers that
weren't explicitly converted to support flow control before. It's
unclear whether flow control actually works with these but typically
it should and their net behavior should be more correct with these
changes in place than without if the MAC driver sets MIIF_DOPAUSE.

Obtained from: NetBSD (partially)
Reviewed by: yongari (earlier version), silence on arch@ and net@

Probe the PHY accompanying BCM57765.
Tested by: Paul Thornton

MFC after: 1 week

Add Realtek RTL8201E 10/100 PHY found in RTL8105E controller. The
exact model name is not clear yet. All previous RTL8201 10/100 PHYs
used 0x8201 in MII_PHYIDR2 which in turn makes model number 0x20
but this PHY used new model number 0x08.

Add RDC Semiconductor R6040 10/100 PHY driver.

- Also probe BCM5214 and BCM5222.
- Add some DSP init code for BCM5221. The values derived from Apple's GMAC
driver and the same init code also exists in Linux's sungem_phy driver.
- Only read media status bits when they are valid.

Obtained from: NetBSD, OpenBSD

Recognize the BCM5482S.

Add BCM5717C 10/100/1000TX PHY id.

Add F1 PHY found on Atheros AR8151 v2.0 PCIe gigabit ethernet
controller.

Marvell model number 0x06 is 88E1101 PHY.

Add Marvell PHYG65G Gigabit PHY which is found on 88E8059 Yukon Optima.

Tested by: James LaLagna < jameslalagna <> gmail dot com >
MFC after: 5 days

Add Agere ET1011 PHY which is found on Belkin F5D5055 USB
controller. Unlike Agere ET1011C, Agere ET1011 does not seem to
need special DSP programming to workaround silicon bug.

- Added support for 5709S/5716S PHYs.

Submitted by: pyunyh
MFC after: 2 weeks

The NetBSD Foundation has granted permission to remove clause 3 and 4 from
the software.

Obtained from: NetBSD

Add support for BCM54K2 found in combination with Apple K2 GMAC.

Submitted by: Andreas Tobler
Obtained from: OpenBSD
MFC after: 1 week

Add BCM5754 PHY id that is found on Dell Studio XPS 16.

Tested by: scf
MFC after: 1 week

Add BCM5761 PHY id.

- Also probe DP83865, which is an is an ultra low power version
of the DP83861 and DP83891.
- Reset the PHY during attach so it's in a known state.
- Add a comment describing why we hardwire 10baseT support in
the BMSR.
- Always explicitly set IFM_HDX for half-duplex. [1]

Obtained from: OpenBSD [1]
MFC after: 2 weeks

Add driver support for 88E3016 PHY which is found on Marvell Yukon
FE+ controller. Due to the severe silicon bugs for Yukon FE+,
88E3016 seems to require more workarounds. However I'm not sure
whether the workaround is PHY specific or only applicable to Yukon
FE+. The datasheet for the PHY is publicly available but it lacks
several details for the workaround used in this change. The
workaround information was obtained from Linux. Many thanks to
Yukon FE+ users who helped me add 88E3016 support.

Tested by: bz, Tanguy Bouzeloc ( the.zauron <> gmail dot com )
Bruce Cran ( bruce <> cran dot org dot uk )
Michael Reifenberger ( mike <> reifenberger dot com )
Stephen Montgomery-Smith ( stephen <> missouri dot edu )

Add PHY entry for the ASIX 88x90 internal PHYs.

Correct PHY description and OUI of VSC8211. Previously VSC8211 was
not recognized by ciphy(4) due to the incorrect OUI.

Reported by: nork
Tested by: nork

- Add driver for Attansic L2 FastEthernet controller found on
Asus EeePC and some Asus mainboards.

Reviewed by: yongari, rpaulo, jhb
Tested by: many
Approved by: kib (mentor)
MFC after: 1 week

Add Vitesse VSC8211 PHY which is found on Planex GU-1000T.

HW donated by: nork

Recognize 88E1116R phy variation. This part is found on some embedded devices.

Obtained from: Semihalf

Add et(4), a port of DragonFly's Agere ET1310 10/100/Gigabit
Ethernet device driver, written by sephe@

Obtained from: DragonFly
Sponsored by: iXsystems
MFC after: 2 weeks

This is a rewritten driver for the SMSC LAN91C111. It's based in part on the
sn(4) driver and also looking at newer drivers. The reason for the rewrite is
to support MII and to try and resolve some performance issues found when trying
to use the sn(4) driver on the Gumstix network boards.

For reference, the SMSC LAN91C111 is a non-PCI ethernet part whose lineage
dates back to Ye Olde Days of ISA. It seems to get some use in the embedded
space these days on parts lacking on-board MACs or on-board PCI controllers,
such as the XScale PXA line of ARM CPUs.

This also includes a driver for the SMSC LAN83C183 10/100 PHY.

Man page to follow.

Add JMicron JMP202/JMP211 PHY driver.

Add Attansic/Atheros F1 PHY driver.

Add support for the BCM5906[M] adapters. These adapters only support
10/100 operation and place the mailbox registers at a different offset.
They also do not have an EEPROM, so the MAC address must be read from
NVRAM instead.

MFC after: 1 month
PR: kern/118975
Submitted by: benjsc, Thomas Nyström thn at saeab dot se
Submitted by: sephe (original patch for DragonflyBSD)

Recognize Cicada CS8244 phy chip (among others, can be found on MPC8572DS
development systems).

Obtained from: Freescale, Semihalf

Add support for IC Plus IP1001 PHY.

Tested by: Stuart Fraser < stuart AT stuartfraser DOT net >

Flesh out support for the BCM5722 by recognizing the phy on the 5722 and
the specific ASIC revision.

MFC after: 1 week
Obtained from: OpenBSD (mii/phy bits)

- Add PHY ID for BCM5709C 1000Base-T controllers.

MFC after: 1 week

Recognize the quad-port Cicada (Vitesse) CS8204 10/100/1000TX PHY.

This PHY is found on many embedded development boards: among others MPC8555CDS
evaluation systems use it.

Approved by: cognet (mentor)
MFp4: e500

Add a driver for the National Semiconductor DP83815, DP83843 and
DP83847 PHYs. The main reason for using a specific driver for these
PHYs are reset quirks similar to the nsphy(4) driven DP83840A.

PR: 112654
Obtained from: NetBSD
MFC after: 2 weeks
Thanks to: mlaier for testing w/ DP83815

Add a newer RTL8211B(L) PHY.

Add ICS1889/ICS1892/ICS1893 PHY.

Submitted by: Ed Schouten <ed@fxq.nl>

New features:
- Moved BCM5706S/5708S SerDes support to brgphy (since they are not technically
TBI interfaces)
- Added 2.5G support for BCM5708S

Comments:
Since this driver is shared with bge I tested several available controllers
supported by bge and all worked as expected, however the list was not
exhaustive. Need wider testing.

MFC after: 4 weeks

Add IC Plus IP101 PHY

Add OUI for Vitesse Semiconductor.
Add Vitesse VSC8601 PHY.

Let brgphy(4) attach for the Broadcom BCM5755 ASIC based chipsets
as well.

Obtained from: OpenBSD
MFC after: 1 week

Restore support for the 5706C bce(4) phy that was broken during the
addition of SerDes support. According to the docs, the 5706C and 5708C
phys are supposed to use the same MII model that is separate from the
SerDes parts, but the 5706C actually uses the MII model of the SerDes
parts. To fix this, readd the old 5706C entry to miidevs and add a
special check in brgphy_probe() for phys that match the 5706C ID. If
the phy is supported by the gentbi(4) driver, then it's a SerDes phy, so
we fail the probe and let gentbi(4) grab it. Otherwise, it's a 5706C phy,
so we let brgphy(4) grab it.

In coordination with: dwhite

Collapse 5706C and 5708C PHYs into one entry. ID 0x15 is actually used for
the SERDES PHY on these chips and we want gentbi to pick this up, not brgphy.

- Fix BCM5754 support found in Dell PowerEdge SC440.
- Move some PHY bug detections from brgphy.c to if_bge.c.
- Do not penalize working PHYs.
- Re-arrange bge_flags roughly by their categories.
- Fix minor style(9) nits.

PR: kern/107257
Obtained from: OpenBSD
Tested by: Mike Hibler <mike at flux dot utah dot edu>

MFp4: add basic driver for RTL8305SC switch in PHY emulation

Add a bunch of new Marvell PHY ids.

Teach the brgphy about some new Broadcom IDs.

Submitted by: David Christenson
Sponsored by: www.UIA.net

- Add another Altima PHY, which is a AC101 workalike and integrated
in at least ADMtek ADM8511 but apparently is not mentioned in any
publically available data sheet so the actual identifier is unknown.
- Add Davicom DM9102 PHY.
- Add DM9101 to the description of AMD 79C873 as at least some Davicom
DM9101F identify identical to AMD 79C873.

Obtained from: NetBSD
MFC after: 2 weeks

Add Broadcom BCM5752 PHY id.

Add IC Plus IP1000A integrated PHY id.

Add a driver for the Broadcom NetXtreme II (BCM5706/BCM5708)
PCI/PCIe Gigabit Ethernet adapeter.

Submitted by: David Christensen

Add basic support for BCM5780 PHY.

Submitted by: grehan
Approved by: glebius (mentor)
MFC after: 1 week

Support the 5714C

Submitted by: John Cagle <john dot cagle at hp dot com>

Add support for the BCM5750/5751. Unfortunately the documentation
I have from Broadcom does not give much information on these devices,
so the Broadcom Linux driver was used for clues to what these chips
support. It turns out they are similar to the 5705 with the 5751
being the PCI-Express version and needing special work-arounds and
settings.

Add device driver support for the VIA Networking Technologies
VT6122 gigabit ethernet chip and integrated 10/100/1000 copper PHY.
The vge driver has been added to GENERIC for i386, pc98 and amd64,
but not to sparc or ia64 since I don't have the ability to test
it there. The vge(4) driver supports VLANs, checksum offload and
jumbo frames.

Also added the lge(4) and nge(4) drivers to GENERIC for i386 and
pc98 since I was in the neighborhood. There's no reason to leave them
out anymore.

Add support for SK-9521 V2.0 and 3COM 3C940.

Tested at 100Mbit only, using Asus P4P800 onboard 3C940.
The -stable version of this patch I have in use for ~2 weeks now, and works
just fine for me.

Based on: Nathan L. Binkert's patch for OpenBSD
Patch submitted by and thanks to: Jung-uk Kim <jkim@niksun.com>
MFC after: 2 weeks

Add a PHY driver to support the built-in gigE PHY in the 8169S/8110S
ethernet chips. This driver is pretty simple, however it contains
special DSP initialization code which is needed in order to get
the chip to negotiate a gigE link. (This special initialization
may not be needed in subsequent chip revs.) Also:

- Fix typo in if_rlreg.h (RL_GMEDIASTAT_1000MPS -> RL_GMEDIASTAT_1000MBPS)

- Deal with shared interrupts in re_intr(): if interface isn't up,
return.

- Fix another bug in re_gmii_writereg() (properly apply data field mask)

- Allow PHY driver to read the RL_GMEDIASTAT register via the
re_gmii_readreg() register (this is register needed to determine
real time link/media status).

Add a device driver for the Broadcom BCM4401 ethernet controller,
written by Stuart Walsh and Duncan Barclay (with some kibbitzing by
me). I'm checking it in on Stuart's behalf.

The BCM4401 is built into several x86 laptop and desktop systems. For the
moment, I have only enabled it in the x86 kernel config because although
it's a PCI device, I haven't heard of any standalone NICs that use it. If
somebody knows of one, we can easily add it to the other arches.

This driver uses register/structure data gleaned from the Linux
driver released by Broadcom, but does not contain any of the code
from the Linux driver itself. It uses busdma.

Add support for the BCM5705 and its ilk. Changes:

- 5705 doesn't support jumbo frames
- Statistics must be read from registers
- RX return ring must be capped at 512 entries
- Omit initialization of certain device blocks
- Acknowledge link change interrupts by setting the 'link changed'
bit in the status register (used to have no effect)
- Remember to toggle the MI completion bit too
- Set the mbuf low watermark differently (on-chip memory buffers,
not BSD mbufs)
- Don't enable Ethernet@WireSpeed feature for certain 5705 chip revs
- Add additional PCI IDs for 5705 and 5782 parts
- Add a forgotten 5704 PCI ID

Most changes ripped kicking and screaming from the Broadcom linux driver.
Thanks to Paul Saab for sanity testing. (My lack of sanity has been
confirmed.)

Add untested support for the Broadcom 5704.

Obtained from: NetBSD

Partial support for the nVidia nForce2 chipset's on-board Broadcom/Altima PHY
and 3com MAC. Specifications for the Altima PHY are available at:
http://www.altimacom.com/products/ac101L.html

Submitted by: Mikko S. Hyvarinen <morphy@morphy.iki.fi>

Add support for the BCM5703x chips. I do not have one of these
cards to test; however the submitter reports that this patch works
with the on-board interface on the IBM x235 server.

Submitted by: Jung-uk Kim <jkim@niksun.com>
MFC after: 1 month

Add a driver for the Broadcom BCM52xx "mini-theta" PHY. This includes the
internal PHY on the 3COM 3C905B and 3C905C parts, however I've rigged it so
that xlphy (aka exphy) takes precedence for the time being.

If people try this with their xl cards and decide that it's a better choice,
we can switch this later.

This is the PHY used in various iMacs and possibly other GMAC-equipped
Macintoshes with 10/100 PHYs (the ones with 10/100/1000 appear to use brgphy).

Obtained from: NetBSD

Use 3C905C instead of 3c905Cphy as the identifier for the Broadcom PHY used
in the 3C905C. This is mainly cosmetic.

I'm doing this mainly so we share the same identifier as NetBSD.

Teach the rlphy driver how to do parallel link detection. If the link partner
doesn't support NWAY, the RealTek PHY (both the integrated ones on 8139
chips and the RTL8201L 10/100 PHY) will not report the link speed via
the ANLPAR or BMSR registers. For the 8201L, we need to look in magic
vendor-specific PHY register 0x19. For the 8139 MAC+PHY combo, we have
to be able to test the RL_MEDIASTAT register.

The changes to rlphy.c are based largely on the patch from PR 30836,
however I tried to eliminate some magic numbers by creating an entry
for the 8201 PHY in miidevs.

Also updated if_rl.c to allow the rlphy driver to read the RL_MEDIASTAT
register via the rl_miibus_readreg() routine.

Teach the brgphy driver about the BCM5701's internal copper PHY.

Cleanup pass for mii drivers.
. Make internal service routines static.
. Use a consistent ordering of checks in MII_TICK. Do the work in the
mii_phy_tick() subroutine if appropriate.
. Call mii_phy_update() to trigger the callbacks.

Add support for the BCM5401 and BCM5411 10/100/1000Mbps copper gigE PHYs.
This basically updates the brgphy driver to support 10/100 modes in
addition to 1000Mbps modes.

Tweak the xmphy driver a little bit based on something I learned about
the built-in 1000baseX interface in the Level 1 LXT1001 chip. The Level 1
PHY comes up with the isolate bit in the control register set by default,
but it also has the autonegotiate bit set. When you tell the xmphy driver
to select IFM_AUTO mode, it sees that the autoneg bit is already on, and
thus doesn't bother updating the control register. However this means that
the isolate bit is never turned off (unless you manually select 1000baseSX
full or half duplex mode, which does result in the control register being
modified and the ISO bit being turned off).

This subtle and unusual behavioral difference stopped me from being able
to receive packets on the SMC9462TX card for several days, since isolating
the PHY disconnects it from the MAC's data interface. The fix is to omit
the 'is the autoneg big set?' test, since it doesn't really provide much
of an optimization anyway.

This commit also updates the xmphy driver to support the Jato/Level 1
internal PHY. (I'm not sure how Jato Technologies is related to Level 1:
all I know is the OUI from the PHY ID registers maps to Jato in the OUI
database.) This will be used once I add the if_lge driver to support
the LXT10010 chip.

Correctly recognize the i82562{EM} PHYs.

Obtained from: OpenBSD

Add support for gigabit ethernet cards based on the NatSemi DP83820
and DP83821 gigabit ethernet MAC chips and the NatSemi DP83861 10/100/1000
copper PHY. There are a whole bunch of very low cost cards available with
this chipset selling for $150USD or less. This includes the SMC9462TX,
D-Link DGE-500T, Asante GigaNIX 1000TA and 1000TPC, and a couple cards
from Addtron.

This chip supports TCP/IP checksum offload, VLAN tagging/insertion.
2048-bit multicast filter, jumbograms and has 8K TX and 32K RX FIFOs.
I have not done serious performance testing with this driver. I know
it works, and I want it under CVS control so I can keep tabs on it.
Note that there's no serious mutex stuff in here yet either: I need
to talk more with jhb to figure out the right way to do this. That
said, I don't think there will be any problems.

This driver should also work on the alpha. It's not turned on in
GENERIC.

Add Marvell PHY support for 10/100/1000 LIVENGOOD_CU Intel NIC.
Parag Patel did all of the grunt work, so he gets the credit.
Register definitions and actions inferred from a Linux driver,
so Intel also gets some 'credit'.

Add some definitions for Intel 82553 PHYs

Forced commit. Last commit was submitted by Jonathan Chen.

Submitted by: Jonathan Chen

Add mii entry for tdk phy found on some cardbus cards.

Add the ID for the built-in homePNA PHY in the AMD 79C798 controller.

Added Altima Communications OUI and their AC101 10/100
media interface to the list of known chips.

miidevs.h regenerated also.

Add entries for the XMAC II's internal PHY and the Broadcom BCM5400
1000baseTx PHY.

$Id$ -> $FreeBSD$

The ASIC on the 3c905C appears to be manufactured by Broadcom (previous
ones were made by Lucent). The Broadcom chip also appears to use an
internal PHY made by Broadcom which uses the Broadcom OUI. This is different
from previous ASICs which always returned 0 in the PHY ID registers.
To account for this, I added the necessary ID values for the Broadcom
PHY so that it can be detected and attached using the 3Com PHY driver
instead of defaulting to the generic one.

$Id$ -> $FreeBSD$

This commit adds support for the NetBSD MII abstraction layer and
MII-compliant PHY drivers. Many 10/100 ethernet NICs available today
either use an MII transceiver or have built-in transceivers that can
be programmed using an MII interface. It makes sense then to separate
this support out into common code instead of duplicating it in all
of the NIC drivers. The mii code also handles all of the media
detection, selection and reporting via the ifmedia interface.

This is basically the same code from NetBSD's /sys/dev/mii, except
it's been adapted to FreeBSD's bus architecture. The advantage to this
is that it automatically allows everything to be turned into a
loadable module. There are some common functions for use in drivers
once an miibus has been attached (mii_mediachg(), mii_pollstat(),
mii_tick()) as well as individual PHY drivers. There is also a
generic driver for all PHYs that aren't handled by a specific driver.
It's possible to do this because all 10/100 PHYs implement the same
general register set in addition to their vendor-specific register
sets, so for the most part you can use one driver for pretty much
any PHY. There are a couple of oddball exceptions though, hence
the need to have specific drivers.

There are two layers: the generic "miibus" layer and the PHY driver
layer. The drivers are child devices of "miibus" and the "miibus" is
a child of a given NIC driver. The "miibus" code and the PHY drivers
can actually be compiled and kldoaded as completely separate modules
or compiled together into one module. For the moment I'm using the
latter approach since the code is relatively small.

Currently there are only three PHY drivers here: the generic driver,
the built-in 3Com XL driver and the NS DP83840 driver. I'll be adding
others later as I convert various NIC drivers to use this code.

I realize that I'm cvs adding this stuff instead of importing it
onto a separate vendor branch, but in my opinion the import approach
doesn't really offer any significant advantage: I'm going to be
maintaining this stuff and writing my own PHY drivers one way or
the other.