'RELENG_7_0_0_RELEASE'.

This commit was manufactured to restore the state of the 7.0-RELEASE image.

support machines having multiple independently numbered PCI domains
and don't support reenumeration without ambiguity amongst the
devices as seen by the OS and represented by PCI location strings.
This includes introducing a function pci_find_dbsf(9) which works
like pci_find_bsf(9) but additionally takes a domain number argument
and limiting pci_find_bsf(9) to only search devices in domain 0 (the
only domain in single-domain systems). Bge(4) and ofw_pcibus(4) are
changed to use pci_find_dbsf(9) instead of pci_find_bsf(9) in order
to no longer report false positives when searching for siblings and
dupe devices in the same domain respectively.
Along with this change the sole host-PCI bridge driver converted to
actually make use of PCI domain support is uninorth(4), the others
continue to use domain 0 only for now and need to be converted as
appropriate later on.
Note that this means that the format of the location strings as used
by pciconf(8) has been changed and that consumers of <sys/pciio.h>
potentially need to be recompiled.

Suggested by:	jhb
Reviewed by:	grehan, jhb, marcel
Approved by:	re (kensmith), jhb (PCI maintainer hat)

- Simplify the amount of work that has be done for each architecture by
  pushing more of the truly MI code down into the PCI bus driver.
- Don't bind MSI-X indicies to IRQs so that we can allow a driver to map
  multiple MSI-X messages into a single IRQ when handling a message
  shortage.

The changes include:
- Add a new pcib_if method: PCIB_MAP_MSI() which is called by the PCI bus
  to calculate the address and data values for a given MSI/MSI-X IRQ.
  The x86 nexus drivers map this into a call to a new 'msi_map()' function
  in msi.c that does the mapping.
- Retire the pcib_if method PCIB_REMAP_MSIX() and remove the 'index'
  parameter from PCIB_ALLOC_MSIX().  MD code no longer has any knowledge
  of the MSI-X index for a given MSI-X IRQ.
- The PCI bus driver now stores more MSI-X state in a child's ivars.
  Specifically, it now stores an array of IRQs (called "message vectors" in
  the code) that have associated address and data values, and a small
  virtual version of the MSI-X table that specifies the message vector
  that a given MSI-X table entry uses.  Sparse mappings are permitted in
  the virtual table.
- The PCI bus driver now configures the MSI and MSI-X address/data
  registers directly via custom bus_setup_intr() and bus_teardown_intr()
  methods.  pci_setup_intr() invokes PCIB_MAP_MSI() to determine the
  address and data values for a given message as needed.  The MD code
  no longer has to call back down into the PCI bus code to set these
  values from the nexus' bus_setup_intr() handler.
- The PCI bus code provides a callout (pci_remap_msi_irq()) that the MD
  code can call to force the PCI bus to re-invoke PCIB_MAP_MSI() to get
  new values of the address and data fields for a given IRQ.  The x86
  MSI code uses this when an MSI IRQ is moved to a different CPU, requiring
  a new value of the 'address' field.
- The x86 MSI psuedo-driver loses a lot of code, and in fact the separate
  MSI/MSI-X pseudo-PICs are collapsed down into a single MSI PIC driver
  since the only remaining diff between the two is a substring in a
  bootverbose printf.
- The PCI bus driver will now restore MSI-X state (including programming
  entries in the MSI-X table) on device resume.
- The interface for pci_remap_msix() has changed.  Instead of accepting
  indices for the allocated vectors, it accepts a mini-virtual table
  (with a new length parameter).  This table is an array of u_ints, where
  each value specifies which allocated message vector to use for the
  corresponding MSI-X message.  A vector of 0 forces a message to not
  have an associated IRQ.  The device may choose to only use some of the
  IRQs assigned, in which case the unused IRQs must be at the "end" and
  will be released back to the system.  This allows a driver to use the
  same remap table for different shortage values.  For example, if a driver
  wants 4 messages, it can use the same remap table (which only uses the
  first two messages) for the cases when it only gets 2 or 3 messages and
  in the latter case the PCI bus will release the 3rd IRQ back to the
  system.

MFC after:	1 month

- First off, device drivers really do need to know if they are allocating
  MSI or MSI-X messages.  MSI requires allocating powerof2() messages for
  example where MSI-X does not.  To address this, split out the MSI-X
  support from pci_msi_count() and pci_alloc_msi() into new driver-visible
  functions pci_msix_count() and pci_alloc_msix().  As a result,
  pci_msi_count() now just returns a count of the max supported MSI
  messages for the device, and pci_alloc_msi() only tries to allocate MSI
  messages.  To get a count of the max supported MSI-X messages, use
  pci_msix_count().  To allocate MSI-X messages, use pci_alloc_msix().
  pci_release_msi() still handles both MSI and MSI-X messages, however.
  As a result of this change, drivers using the existing API will only
  use MSI messages and will no longer try to use MSI-X messages.
- Because MSI-X allows for each message to have its own data and address
  values (and thus does not require all of the messages to have their
  MD vectors allocated as a group), some devices allow for "sparse" use
  of MSI-X message slots.  For example, if a device supports 8 messages
  but the OS is only able to allocate 2 messages, the device may make the
  best use of 2 IRQs if it enables the messages at slots 1 and 4 rather
  than default of using the first N slots (or indicies) at 1 and 2.  To
  support this, add a new pci_remap_msix() function that a driver may call
  after a successful pci_alloc_msix() (but before allocating any of the
  SYS_RES_IRQ resources) to allow the allocated IRQ resources to be
  assigned to different message indices.  For example, from the earlier
  example, after pci_alloc_msix() returned a value of 2, the driver would
  call pci_remap_msix() passing in array of integers { 1, 4 } as the
  new message indices to use.  The rid's for the SYS_RES_IRQ resources
  will always match the message indices.  Thus, after the call to
  pci_remap_msix() the driver would be able to access the first message
  in slot 1 at SYS_RES_IRQ rid 1, and the second message at slot 4 at
  SYS_RES_IRQ rid 4.  Note that the message slots/indices are 1-based
  rather than 0-based so that they will always correspond to the rid
  values (SYS_RES_IRQ rid 0 is reserved for the legacy INTx interrupt).
  To support this API, a new PCIB_REMAP_MSIX() method was added to the
  pcib interface to change the message index for a single IRQ.

Tested by:	scottl

style(9) and avoids mixing the two formats.

- Add 3 new functions to the pci_if interface along with suitable wrappers
  to provide the device driver visible API:
  - pci_alloc_msi(dev, int *count) backed by PCI_ALLOC_MSI().  '*count'
    here is an in and out parameter.  The driver stores the desired number
    of messages in '*count' before calling the function.  On success,
    '*count' holds the number of messages allocated to the device.  Also on
    success, the driver can access the messages as SYS_RES_IRQ resources
    starting at rid 1.  Note that the legacy INTx interrupt resource will
    not be available when using MSI.  Note that this function will allocate
    either MSI or MSI-X messages depending on the devices capabilities and
    the 'hw.pci.enable_msix' and 'hw.pci.enable_msi' tunables.  Also note
    that the driver should activate the memory resource that holds the
    MSI-X table and pending bit array (PBA) before calling this function
    if the device supports MSI-X.
  - pci_release_msi(dev) backed by PCI_RELEASE_MSI().  This function
    releases the messages allocated for this device.  All of the
    SYS_RES_IRQ resources need to be released for this function to succeed.
  - pci_msi_count(dev) backed by PCI_MSI_COUNT().  This function returns
    the maximum number of MSI or MSI-X messages supported by this device.
    MSI-X is preferred if present, but this function will honor the
    'hw.pci.enable_msix' and 'hw.pci.enable_msi' tunables.  This function
    should return the largest value that pci_alloc_msi() can return
    (assuming the MD code is able to allocate sufficient backing resources
    for all of the messages).
- Add default implementations for these 3 methods to the pci_driver generic
  PCI bus driver.  (The various other PCI bus drivers such as for ACPI and
  OFW will inherit these default implementations.)  This default
  implementation depends on 4 new pcib_if methods that bubble up through
  the PCI bridges to the MD code to allocate IRQ values and perform any
  needed MD setup code needed:
  - PCIB_ALLOC_MSI() attempts to allocate a group of MSI messages.
  - PCIB_RELEASE_MSI() releases a group of MSI messages.
  - PCIB_ALLOC_MSIX() attempts to allocate a single MSI-X message.
  - PCIB_RELEASE_MSIX() releases a single MSI-X message.
- Add default implementations for these 4 methods that just pass the
  request up to the parent bus's parent bridge driver and use the
  default implementation in the various MI PCI bridge drivers.
- Add MI functions for use by MD code when managing MSI and MSI-X
  interrupts:
  - pci_enable_msi(dev, address, data) programs the MSI capability address
    and data registers for a group of MSI messages
  - pci_enable_msix(dev, index, address, data) initializes a single MSI-X
    message in the MSI-X table
  - pci_mask_msix(dev, index) masks a single MSI-X message
  - pci_unmask_msix(dev, index) unmasks a single MSI-X message
  - pci_pending_msix(dev, index) returns true if the specified MSI-X
    message is currently pending
- Save the MSI capability address and data registers in the pci_cfgreg
  block in a PCI devices ivars and restore the values when a device is
  resumed.  Note that the MSI-X table is not currently restored during
  resume.
- Add constants for MSI-X register offsets and fields.
- Record interesting data about any MSI-X capability blocks we come
  across in the pci_cfgreg block in the ivars for PCI devices.

Tested on:	em (i386, MSI), bce (amd64/i386, MSI), mpt (amd64, MSI-X)
Reviewed by:	scottl, grehan, jfv
MFC after:	2 months

remove sk's own implementation, and use the new calls to get the data...

Reviewed by:	-arch

share devclass pointers, a mistake I've encouraged in the past) and
move the declaration of the pci_driver kobj class from cardbus.c to
pci_private.h so that other drivers can inherit from pci_driver.