fpga: dfl: add basic support for DFHv1

Version 1 of the Device Feature Header (DFH) definition adds
functionality to the Device Feature List (DFL) bus.

A DFHv1 header may have one or more parameter blocks that
further describes the HW to SW. Add support to the DFL bus
to parse the MSI-X parameter.

The location of a feature's register set is explicitly
described in DFHv1 and can be relative to the base of the DFHv1
or an absolute address. Parse the location and pass the information
to DFL driver.

Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230115151447.1353428-4-matthew.gerlach@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fpga: dfl: expose feature revision from struct dfl_device

DFL device drivers have a common need for checking feature revision
information from the DFL header, as well as other common DFL information
like the already exposed feature id and type.

This patch exposes the feature revision information directly via the DFL
device data structure.

Since the DFL core code has already read the DFL header, this this patch
saves additional mmio reads from DFL device drivers too.

Acked-by: Wu Hao <hao.wu@intel.com>
Acked-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Martin Hundebøll <mhu@silicom.dk>
Signed-off-by: Moritz Fischer <mdf@kernel.org>

fpga: dfl: move dfl bus related APIs to include/linux/dfl.h

Now the dfl drivers could be made as independent modules and put in
different folders according to their functionalities. In order for
scattered dfl device drivers to include dfl bus APIs, move the
dfl bus APIs to a new header file in the public folder.

[mdf@kernel.org: Fixed up header guards to match filename]

Reviewed-by: Tom Rix <trix@redhat.com>
Acked-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Link: https://lore.kernel.org/r/20210107043714.991646-7-mdf@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>