drm/xe/pat: annotate pat_index with coherency mode

Future uapi needs to give userspace the ability to select the pat_index
for a given vm_bind. However we need to be able to extract the coherency
mode from the provided pat_index to ensure it's compatible with the
cpu_caching mode set at object creation. There are various security
reasons for why this matters. However the pat_index itself is very
platform specific, so seems reasonable to annotate each platform
definition of the pat table. On some older platforms there is no
explicit coherency mode, so we just pick whatever makes sense.

v2:
- Simplify with COH_AT_LEAST_1_WAY
- Add some kernel-doc
v3 (Matt Roper):
- Some small tweaks
v4:
- Rebase
v5:
- Rebase on Xe2 PAT additions
v6:
- Rebase on removal of coh_mode from uapi

Bspec: 45101, 44235 #xe
Bspec: 70552, 71582, 59400 #xe2
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Pallavi Mishra <pallavi.mishra@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Filip Hazubski <filip.hazubski@intel.com>
Cc: Carl Zhang <carl.zhang@intel.com>
Cc: Effie Yu <effie.yu@intel.com>
Cc: Zhengguo Xu <zhengguo.xu@intel.com>
Cc: Francois Dugast <francois.dugast@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Pallavi Mishra <pallavi.mishra@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drm/xe/pat: Add debugfs node to dump PAT

This is useful to debug cache issues, to double check if the PAT
indexes match what they were supposed to be set to from spec.

v2: Add separate functions for XeHP, XeHPC and XeLPG so it correctly
reads the index based on MCR/REG registers and also decodes the
fields (Matt Roper)
v3: Starting with XeHPC, do not translate values to human-readable
formats as the main goal is to make it easy to compare the table
with the spec. Also, share a single array for xelp/xehp str map
(Matt Roper)

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://lore.kernel.org/r/20231006182325.3617685-3-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drm/xe: Use vfunc to initialize PAT

Split the PAT initialization between SW-only and HW. The _early() only
sets up the ops and data structure that are used later to program the
tables. This allows the PAT to be easily extended to other platforms.

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://lore.kernel.org/r/20230927193902.2849159-6-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drm/xe/pat: Move PAT setup to a dedicated file

PAT handling is growing in complexity and will continue to do so in
upcoming platforms. Separate it out to a dedicated file to keep things
tidy.

The code is moved as-is here (aside from a few unused #define's that are
just dropped); further changes will come in future patches.

Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Link: https://lore.kernel.org/r/20230324210415.2434992-2-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>