Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Correct spelling in comments.

Submitted by: brucec

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

- 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]

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>

Spelling and style fixes.

Obtained from: NetBSD

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.

Miscellaneous fixes:
- always reinitialize the rx descriptors, even if the mbuf is kept.
This should fix the hangs on ifconfig that were observed
- on an rx overflow, reinitialize the descriptor so that the interface
will not hang
- correct some bus_dmamap_sync() calls
- correct some debug messages
- some minor nits

Don't treat statistics counter wrap-overs as errors.

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).