Add support for the ISSEI (Intel Silicon Security Engine Interface)
HECI PCI devices.
Add the necessary PCI handling routines, hardware definitions,
register mappings and hardware access routines.

This enables the communication via HECI PCI device advertized by BIOS.

Reviewed-by: Karol Wachowski <karol.wachowski@linux.intel.com>
Co-developed-by: Vitaly Lubart <lubvital@gmail.com>
Signed-off-by: Vitaly Lubart <lubvital@gmail.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Link: https://patch.msgid.link/20260513-issei-for-upstream-v1-4-f590038678f9@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The ISSEI (Intel Silicon Security Engine Interface)
subsystem provides a communication channel between the host and the
Silicon Security Engine.

Prepare basic driver functions and character device
for user-space communication.
Add DMA access routines for ISSEI HECI devices.
Add of DMA-related structures and implementation of routines for
setting up DMA, as well as reading and writing DMA buffers.

Reviewed-by: Karol Wachowski <karol.wachowski@linux.intel.com>
Co-developed-by: Vitaly Lubart <lubvital@gmail.com>
Signed-off-by: Vitaly Lubart <lubvital@gmail.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Link: https://patch.msgid.link/20260513-issei-for-upstream-v1-1-f590038678f9@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>