Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

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

Obtained from: NetBSD

o Disable HMEDEBUG by default.
o Add CTASSERTs ensuring that HME_NRXDESC and HME_NTXDESC are set to
legal values.
o Use appropriate maxsize, nsegments and maxsegsize parameters when
creating DMA tags and correct some comments related to them.
o The FreeBSD bus_dmamap_sync(9) supports ored together flags for quite
some time now so collapse calls accordingly.
o Add missing BUS_DMASYNC_PREREAD when syncing the control DMA maps in
hme_rint() and hme_start_locked().
o Keep state of the link state and use it to enable or disable the MAC
in hme_mii_statchg() accordingly as well as to return early from
hme_start_locked() in case the link is down.
o Introduce a sc_flags and use it to replace individual members like
sc_pci.
o Add bus_barrier(9) calls to hme_mac_bitflip(), hme_mii_readreg(),
hme_mii_writereg() and hme_stop() to ensure the respective bit
has been written before we starting polling on it and for the right
bits to change.
o Rather just returning in case hme_mac_bitflip() fails and leaving us
in an undefined state report the problem and move on; chances are
the requested configuration will become active shortly after.
o Don't call hme_start_locked() in hme_init_locked() unconditionally
but only after calls to hme_init_locked() when it's appropriate, i.e.
in hme_watchdog().
o Add a KASSERT which asserts nsegs is valid also to hme_load_txmbuf().
o In hme_load_txmbuf():
- use a maximum of the newly introduced HME_NTXSEGS segments instead
of the incorrect HME_NTXQ, which reflects the maximum TX queue
length, for loading the mbufs and put the DMA segments back onto
the stack instead of the softc as 16 should be ok there.
- use the common errno(2) return values instead of homegrown ones,
- given that hme_load_txmbuf() is allowed to fail resulting in a
packet drop for quite some time now implement the functionality of
hme_txcksum() by means of m_pullup(9), which de-obfuscates the code
and allows to always retrieve the correct length of the IP header, [1]
- also add a KASSERT which asserts nsegs is valid,
- take advantage of m_collapse(9) instead of m_defrag(9) for
performance reasons.
o Don't bother to check whether the interface is running or whether its
queue is empty before calling hme_start_locked() in hme_tint(), the
former will check these anyway.
o In hme_intr() call hme_rint() before hme_tint() as gem_tint() may
take quite a while to return when it calls hme_start_locked().
o Get rid of sc_debug and just check if_flags for IFF_DEBUG directly.
o Add a shadow sc_ifflags so we don't reset the chip when unnecessary.
o Handle IFF_ALLMULTI correctly. [2]
o Use PCIR_BAR instead of a homegrown macro.
o Replace sc_enaddr[6] with sc_enaddr[ETHER_ADDR_LEN].
o Use the maximum of 256 TX descriptors for better performance as using
all of them has no additional static cost rather than using just half
of them.

Reported by: rwatson [2]
Suggested by: yongari [1]
Reviewed by: yongari
MFC after: 1 month

- Use the hme_tick() callout instead of if_slowtimo() for driving
hme_watchdog() in order to avoid races accessing if_timer.
- Use bus_get_dma_tag() so hme(4) works on platforms requiring it.
- Don't bother to set if_mtu to ETHERMTU, ether_ifattach() does that.

- Convert hme(4) to use TX side bus_dmamap_load_mbuf_sg(9).
- Move hardware counter reading/zeroing to hme_tick(). This saves
8 register access per interrupt. [1]
- Use imax macro for getting max. argument between two integers.
- Invoke bus_dmamap_sync(9) first before freeing mbuf.
- Check driver queue first to reduce locking operation in hme_start_locked()
and interrupt handler.
- Simplyfy watchdog timer setup in interrupt handler.
- Don't log normal errors such as RX overrun. If we have DMA stuck
condition, reinitialize the driver and log it.

Reviewed by: marius
Obtained from: OpenBSD [1]

Stop embedding struct ifnet at the top of driver softcs. Instead the
struct ifnet or the layer 2 common structure it was embedded in have
been replaced with a struct ifnet pointer to be filled by a call to the
new function, if_alloc(). The layer 2 common structure is also allocated
via if_alloc() based on the interface type. It is hung off the new
struct ifnet member, if_l2com.

This change removes the size of these structures from the kernel ABI and
will allow us to better manage them as interfaces come and go.

Other changes of note:
- Struct arpcom is no longer referenced in normal interface code.
Instead the Ethernet address is accessed via the IFP2ENADDR() macro.
To enforce this ac_enaddr has been renamed to _ac_enaddr.
- The second argument to ether_ifattach is now always the mac address
from driver private storage rather than sometimes being ac_enaddr.

Reviewed by: sobomax, sam

Make hme(4) mpsafe
- Let hme_start()/hme_init() acquire lock and then call
hme_start_locked()/hme_init_locked() respectivly.
- Teardown interrupt handler before hme_detach().
- Remove IFF_NEEDSGIANT flag and mark interrupt handler INTR_MPSAFE.
- Set callout handler to CALLOUT_MPSAFE.
- Add locks in hme MII interface.

Reviewed by: jake
Tested by: Julian C. Dunn <jdunn at opentrend dot net>
MFC after: 2 weeks

- Use bus_space_subregion() rather than arithmetic on bus_space_handle_t. [1]
- Properly use the error variable and return it on failure in the attach-
routines.

Reviewed by: tmm
Inspired by: NetBSD [1]

Implement TCP/UDP Transmit/Receive checksum offload.
Since HME doesn't compensate the checksum for UDP datagram which
can yield to 0x0, UDP transmit checksum offload is disabled by
default. The UDP Transmit checksum offload can be reactivated
by setting special link option link0 with ifconfig(8).

Approved by: jake (mentor)
Reviewed by: tmm
Tested by: Herve Boulouis <amon@sockar.homeip.net>

Add detach, shutdown, suspend and resume methods.

Tested by: jake

Convert to use bus_dmamap_load_mbuf(); decouple software TX descriptors
from the hardware descriptors to avoid the overhead of having a DMA
map for each of them. Bump the number of hardware descriptors to 128,
and use half as many software descriptors for now.
Some minor cleanups.

Assorted fixes:
- remove some useless code from the status change handler that was intended
to enable the the MII drivers for external phys; this is already done
during interface initialization, and the deleted code made some
assumptions about phy addresses that do not seem to hold true on newer
cards. This should get at least one of the two hmes of newer Netra t1
machines working.
- correct the interrupt resource allocation
- bump the number of RX descriptors, lower values cause promblems on some
machines

Add a driver for the Sun HME PCI/SBus ethernet adaptor, which is onboard
in most machines of the Sun Ultra series. This is a port of the NetBSD
driver which I enhanced to make use of the gather functionality and the
configurable RX buffer offset to avoid copying all received/sent packet
(instead, packets will be directly DMAd from mbuf chains and into mbuf
clusters now).