MFC the mpr(4) driver for LSI's 12Gb SAS cards.

This includes r265236, r265237, r265241, r265261, r265386, r265424, and
r265473.

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  r265236 | ken | 2014-05-02 14:25:09 -0600 (Fri, 02 May 2014) | 51 lines

  Bring in the mpr(4) driver for LSI's MPT3 12Gb SAS controllers.

  This is derived from the mps(4) driver, but it supports only the 12Gb
  IT and IR hardware including the SAS 3004, SAS 3008 and SAS 3108.

  Some notes about this driver:
   o The 12Gb hardware can do "FastPath" I/O, and that capability is included in
     this driver.

   o WarpDrive functionality has been removed, since it isn't supported in
     the 12Gb driver interface.

   o The Scatter/Gather list handling code is significantly different between
     the 6Gb and 12Gb hardware.  The 12Gb boards support IEEE Scatter/Gather
     lists.

  Thanks to LSI for developing and testing this driver for FreeBSD.

  share/man/man4/mpr.4:
  	mpr(4) man page.

  sys/dev/mpr/*:
  	mpr(4) driver files.

  sys/modules/Makefile,
  sys/modules/mpr/Makefile:
  	Add a module Makefile for the mpr(4) driver.

  sys/conf/files:
  	Add the mpr(4) driver.

  sys/amd64/conf/GENERIC,
  sys/i386/conf/GENERIC,
  sys/mips/conf/OCTEON1,
  sys/sparc64/conf/GENERIC:
  	Add the mpr(4) driver to all config files that currently
  	have the mps(4) driver.

  sys/ia64/conf/GENERIC:
  	Add the mps(4) and mpr(4) drivers to the ia64 GENERIC
  	config file.

  sys/i386/conf/XEN:
  	Exclude the mpr module from building here.

  Submitted by:	Steve McConnell <Stephen.McConnell@avagotech.com>
  Tested by:	Chris Reeves <chrisr@spectralogic.com>
  Sponsored by:	LSI, Spectra Logic
  Relnotes:	LSI 12Gb SAS driver mpr(4) added

  ------------------------------------------------------------------------
  ------------------------------------------------------------------------
  r265237 | ken | 2014-05-02 14:36:20 -0600 (Fri, 02 May 2014) | 8 lines

  Add the mpr(4) man page to the man4 Makefile.

  This should have been included in r265236.

  Submitted by:	Steve McConnell <Stephen.McConnell@avagotech.com>
  Sponsored by:	LSI, Spectra Logic

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  r265241 | brueffer | 2014-05-02 15:14:28 -0600 (Fri, 02 May 2014) | 2 lines

  Use our standard SYNOPSIS wording; perform some cleanup while here.

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  r265261 | brueffer | 2014-05-03 05:15:28 -0600 (Sat, 03 May 2014) | 2 lines

  Add a missing colon.

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  r265386 | ken | 2014-05-05 13:53:03 -0600 (Mon, 05 May 2014) | 15 lines

  Adjust #if statements inside mprsas_send_smpcmd() to more accurately
  reflect when unmapped I/O support was added.

  For FreeBSD 10, it arrived just prior to __FreeBSD_version 1000028.
  For FreeBSD 9, it arrived just prior to __FreeBSD_version 902001.

  Also, fix compiler warnings in mprsas_send_smpcmd() that happen in the
  i386 PAE build for non-unmapped I/O builds.  These were fixed in mps(4)
  in revision 241145, but didn't make it into the mpr(4) driver.  This
  change should only affect FreeBSD versions outside the above revisions,
  and thus doesn't affect head.

  Sponsored by:	Spectra Logic Corporation

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  r265424 | ken | 2014-05-06 00:18:43 -0600 (Tue, 06 May 2014) | 33 lines

  Fix a problem with async notifications in the mpr(4) driver.

  This problem only occurs on versions of FreeBSD prior to the recent CAM
  locking changes.  (i.e. stable/9 and older versions of stable/10)  This
  change should be a no-op for head and stable/10.

  If a path isn't specified, xpt_register_async() will create a fully
  wildcarded path and acquire a lock (the XPT lock in older versions,
  and via xpt_path_lock() in newer versions) to call xpt_action() for the
  XPT_SASYNC_CB CCB.  It will then drop the lock and if the requested event
  includes AC_FOUND_DEVICE or AC_PATH_REGISTERED, it will get the caller up
  to date with any device arrivals or path registrations.

  The issue is that before the locking changes, each SIM lock would get
  acquired in turn during the EDT tree traversal process.  If a path is
  specified for xpt_register_async(), it won't acquire and drop its own lock,
  but instead expects the caller to hold its own SIM lock.  That works for
  the first part of xpt_register_async(), but causes a recursive lock
  acquisition once the EDT traversal happens and it comes to the SIM in
  question.  And it isn't possible to call xpt_action() without holding a SIM
  lock.

  The locking changes fix this by using the XPT topology lock for EDT
  traversal, so it is no longer an issue to hold the SIM lock while calling
  xpt_register_async().

  The solution for FreeBSD versions before the locking changes is to request
  notification of all device arrivals (so we pass a NULL path into
  xpt_register_async()) and then filter out the arrivals that are not ours.

  Sponsored by:	Spectra Logic Corporation

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  r265473 | ken | 2014-05-06 16:13:38 -0600 (Tue, 06 May 2014) | 7 lines

  Change the device name for mpr(4) from /dev/mpr_N to /dev/mprN.

  This is more consistent with the existing mps(4) behavior.

  Reviewed by:	Steve McConnell <stephen.mcconnell@avagotech.com>

  ------------------------------------------------------------------------

Submitted by:	Steve McConnell <Stephen.McConnell@avagotech.com>
Tested by:	Chris Reeves <chrisr@spectralogic.com>
Sponsored by:	LSI, Spectra Logic
Relnotes:	LSI 12Gb SAS driver mpr(4) added

(cherry picked from commit b9d4693d210b6e2942022d72659029e4abb9a3b5)

Conflicts:
	sys/i386/conf/XEN
MFC mpr(4) changes: r265484, r265485, r265709 and r265712

  ------------------------------------------------------------------------
  r265484 | ken | 2014-05-06 23:11:16 -0600 (Tue, 06 May 2014) | 5 lines

  Remove some debugging code.

  Submitted by:	Steve McConnell <stephen.mcconnell@avagotech.com>

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  r265485 | ken | 2014-05-06 23:14:48 -0600 (Tue, 06 May 2014) | 9 lines

  Hold the SIM lock when calling xpt_create_path() and xpt_action() in
  mprsas_SSU_to_SATA_devices().

  This fixes an assertion on shutdown with INVARIANTS enabled with SATA
  drives present on an IR firmware controller.

  Reviewed by:	Steve McConnell <stephen.mcconnell@avagotech.com>.

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  r265709 | ken | 2014-05-08 14:28:22 -0600 (Thu, 08 May 2014) | 15 lines

  Fix TLR (Transport Layer Retry) support in the mps(4) and mpr(4) drivers.

  TLR is necessary for reliable communication with SAS tape drives.

  This was broken by change 246713 in the mps(4) driver.  It changed the
  cm_data field for SCSI I/O requests to point to the CCB instead of the data
  buffer.  So, instead, look at the CCB's data pointer to determine whether
  or not we're talking to a tape drive.

  Also, take the residual into account to make sure that we don't go off the
  end of the request.

  Sponsored by:	Spectra Logic Corporation

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  r265712 | ken | 2014-05-08 14:46:46 -0600 (Thu, 08 May 2014) | 10 lines

  Add #ifdefs in the mpr(4) driver so that versions of stable/9 that
  have implemented the PIM_NOSCAN rescan functionality will have it
  enabled.

  This is a no-op for head.

  Reviewed by:	slm
  Sponsored by:	Spectra Logic Corporation

  ------------------------------------------------------------------------

Sponsored by:	Spectra Logic, Avago

(cherry picked from commit 4e258ef21ebe273b7eda420ef5fb8d3e311952f5)
Fix mpr build.
Increase taskqueue thread priority from idle to PRIBIO.

Idle priority is not even time-share, so if system is busy in any way,
those events may never be executed.  Since in some cases system waits
for events processed by that thread, that may cause deadlocks.

(cherry picked from commit 215fd01a0d07848d6231068ab978f33cd1e65eec)