Move TLB invalidation code for its own file and document it

There are more things to be added to TLB invalidation. Before doing that, move the code to its own file, and add the relevant documentation.

Patch 1 fixes vma_invalidate_tlb() logic to make it update the right var;

Patch 2 only moves the code and do some function renames. No functional change;

Patch 3 adds documentation for the TLB invalidation algorithm and functions.

---

v3:
- Added a fix for an issue from the last TLB patch series;
- included a better description about the changes on patch 2;
- did some minor fixes at kernel-doc markups;

v2: only patch 2 (kernel-doc) was modified:

- The kernel-doc markups for TLB were added to i915.rst doc;
- Some minor fixes at the texts;
- Use a table instead of a literal block while explaining how the algorithm works. That should make easier to understand the logic, both in text form and after its conversion to HTML/PDF;
- Remove mention for GuC, as this depends on a series that will be sent later.

Chris Wilson (1):
drm/i915/gt: Move TLB invalidation to its own file

Mauro Carvalho Chehab (2):
drm/i915: pass a pointer for tlb seqno at vma_invalidate_tlb() drm/i915/gt: document TLB cache invalidation functions

 Documentation/gpu/i915.rst                |   7 +
 drivers/gpu/drm/i915/Makefile             |   1 +
 drivers/gpu/drm/i915/gem/i915_gem_pages.c |   4 +-
 drivers/gpu/drm/i915/gt/intel_gt.c        | 168 +----------------
 drivers/gpu/drm/i915/gt/intel_gt.h        |  12 --
 drivers/gpu/drm/i915/gt/intel_ppgtt.c     |   2 +-
 drivers/gpu/drm/i915/gt/intel_tlb.c       | 208 ++++++++++++++++++++++
 drivers/gpu/drm/i915/gt/intel_tlb.h       | 128 +++++++++++++
 drivers/gpu/drm/i915/i915_vma.c           |   7 +-
 drivers/gpu/drm/i915/i915_vma.h           |   2 +-
 10 files changed, 355 insertions(+), 184 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/gt/intel_tlb.c
 create mode 100644 drivers/gpu/drm/i915/gt/intel_tlb.h

2.37.1