ntb: intel: add Intel NTB LTR vendor support for gen4 NTB

Intel NTB device has custom LTR management that is not compliant with the
PCIe standard. Add support to set LTR status triggered by link status
change.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

ntb: intel: add hw workaround for NTB BAR alignment

Add NTB_HWERR_BAR_ALIGN hw errata flag to work around issue where the
aligment for the XLAT base must be BAR size aligned rather than 4k page
aligned. On ICX platform, the XLAT base can be 4k page size aligned
rather than BAR size aligned unlike the previous gen Intel NTB. However,
a silicon errata prevented this from working as expected and a workaround
is introduced to resolve the issue.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

NTB: add new parameter to peer_db_addr() db_bit and db_data

NTB door bell usage depends on NTB hardware.

ex: intel NTB gen1 has one peer door bell register which can be controlled
by the bitmap writen to it, while Intel NTB gen3 has a registers
per door bell and the data trigering the each door bell is always 1.

therefore exposing only peer door bell address forcing the user
to be aware of such low level details

Signed-off-by: Leonid Ravich <Leonid.Ravich@emc.com>
Acked-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Acked-by: Allen Hubbe <allenbh@gmail.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

ntb: intel: split out the gen3 code

Move the Intel hw gen3 code to its own source file. The ntb_hw_intel.c was
getting too large and makes it hard to maintain with future hardware
changes.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

ntb: intel: header definitions refactor

Break out the generation specific definitions to different headers

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>