Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

- To avoid having a bunch of locks that end up always getting acquired as
  a group, give each ppc(4) device a mutex which it shares with all the
  child devices including ppbus(4), lpt(4), plip(4), etc.  This mutex
  is then used for all the locking.
- Rework the interrupt handling stuff yet again.  Now ppbus drivers setup
  their interrupt handler during attach and tear it down during detach
  like most other drivers.  ppbus(4) only invokes the interrupt handler
  of the device that currently owns the bus (if any) when an interrupt
  occurs, however.  Also, interrupt handlers in general now accept their
  softc pointers as their argument rather than the device_t.  Another
  feature of the ppbus interrupt handlers is that they are called with
  the parent ppc device's lock already held.  This minimizes the number
  of lock operations during an interrupt.
- Mark plip(4), lpt(4), pcfclock(4), ppi(4), vpo(4) MPSAFE.
- lpbb(4) uses the ppc lock instead of Giant.
- Other plip(4) changes:
  - Add a mutex to protect the global tables in plip(4) and free them on
    module unload.
  - Add a detach routine.
  - Split out the init/stop code from the ioctl routine into separate
    functions.
- Other lpt(4) changes:
  - Use device_printf().
  - Use a dedicated callout for the lptout timer.
  - Allocate the I/O buffers at attach and detach rather than during
    open and close as this simplifies the locking at the cost of
    1024+32 bytes when the driver is attached.
- Other ppi(4) changes:
  - Use an sx lock to serialize open and close.
  - Remove unused HADBUS flag.
  - Add a detach routine.
  - Use a malloc'd buffer for each read and write to avoid races with
    concurrent read/write.
- Other pps(4) changes:
  - Use a callout rather than a callout handle with timeout().
  - Conform to the new ppbus requirements (regular mutex, non-filter
    interrupt handler).  pps(4) is probably going to have to become a
    standalone driver that doesn't use ppbus(4) to satisfy it's
    requirements for low latency as a result.
  - Use an sx lock to serialize open and close.
- Other vpo(4) changes:
  - Use the parent ppc device's lock to create the CAM sim instead of
    Giant.
- Other ppc(4) changes:
  - Fix ppc_isa's detach method to detach instead of calling attach.

Tested by:	  no one :-(

- Retire IVARs for passing IRQs around.  Instead, ppbus and ppc now allow
  child devices to access the interrupt by via a rid 0 IRQ resource
  using bus_alloc_resource_any().
- ppc creates its own interrupt event to manage the interrupt handlers of
  child devices.  ppc does not allow child devices to use filters.  It
  could allow this if needed, but none of the current drivers use them
  and it adds a good bit of complication.  It uses
  intr_event_execute_handlers() to fire the child device interrupt handlers
  from its threaded interrupt handler.
- Remove the ppbus_dummy_intr() hack.  Now the ppc device always has an
  interrupt handler registered and we no longer bounce all the way up to
  nexus to manage adding/removing ppbus child interrupt handlers.  Instead,
  the child handlers are added and removed to the private interrupt event
  in the ppc device.

o  Properly use rman(9) to manage resources. This eliminates the
   need to puc-specific hacks to rman. It also allows devinfo(8)
   to be used to find out the specific assignment of resources to
   serial/parallel ports.
o  Compress the PCI device "database" by optimizing for the common
   case and to use a procedural interface to handle the exceptions.
   The procedural interface also generalizes the need to setup the
   hardware (program chipsets, program clock frequencies).
o  Eliminate the need for PUC_FASTINTR. Serdev devices are fast by
   default and non-serdev devices are handled by the bus.
o  Use the serdev I/F to collect interrupt status and to handle
   interrupts across ports in priority order.
o  Sync the PCI device configuration to include devices found in
   NetBSD and not yet merged to FreeBSD.
o  Add support for Quatech 2, 4 and 8 port UARTs.
o  Add support for a couple dozen Timedia serial cards as found
   in Linux.

o  Whitespace fixes
o  Non-K&R functions

   end for isa(4).
o  Add a seperate bus frontend for acpi(4) and allow ISA DMA for
   it when ISA is configured in the kernel. This allows acpi(4)
   attachments in non-ISA configurations, as is possible for ia64.
o  Add a seperate bus frontend for pci(4) and detect known single
   port parallel cards.
o  Merge PC98 specific changes under pc98/cbus into the MI driver.
   The changes are minor enough for conditional compilation and
   in this form invites better abstraction.
o  Have ppc(4) usabled on all platforms, now that ISA specifics
   are untangled enough.

      -	Move isa/ppc* to sys/dev/ppc (repo-copy)
      -	Add an attachment method to ppc for puc
      -	In puc we need to walk the chain of parents.
Still to do, is to make ppc(4) & puc(4) work on other platforms.  Testers
wanted.

PR:		38372 (in spirit done differently)
Verified by:	Make universe (if I messed up a platform please fix)