drm/xe: Replace xe_gt_irq_postinstall with xe_irq_enable_hwe

The majority of xe_gt_irq_postinstall() is really focused on the
hardware engine interrupts; other GT-related interrupts such as the GuC
are enabled/disabled independently. Renaming the function and making it
truly GT-specific will make it more clear what the intended focus is.

Disabling/masking of other interrupts (such as GuC interrupts) is
unnecessary since that has already happened during the irq_reset stage,
and doing so will become harmful once the media GT is re-enabled since
calls to xe_gt_irq_postinstall during media GT initialization would
incorrectly disable the primary GT's GuC interrupts.

Also, since this function is called from gt_fw_domain_init(), it's not
necessary to also call it earlier during xe_irq_postinstall; just
xe_irq_resume to handle runtime resume should be sufficient.

v2:
- Drop unnecessary !gt check. (Lucas)
- Reword some comments about enable/unmask for clarity. (Lucas)

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20230601215244.678611-26-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drm/xe: Interrupts are delivered per-tile, not per-GT

IRQ delivery and handling needs to be handled on a per-tile basis. Note
that this is true even for the "GT interrupts" relating to engines and
GuCs --- the interrupts relating to both GTs get raised through a single
set of registers in the tile's sgunit range.

On true multi-tile platforms, interrupts on remote tiles are internally
forwarded to the root tile; the first thing the top-level interrupt
handler should do is consult the root tile's instance of
DG1_MSTR_TILE_INTR to determine which tile(s) had interrupts. This
register is also responsible for enabling/disabling top-level reporting
of any interrupts to the OS. Although this register technically exists
on all tiles, it should only be used on the root tile.

The (mis)use of struct xe_gt as a target for MMIO operations in the
driver makes the code somewhat confusing since we wind up needing a GT
pointer to handle programming that's unrelated to the GT. To mitigate
this confusion, all of the xe_gt structures used solely as an MMIO
target in interrupt code are renamed to 'mmio' so that it's clear that
the structure being passed does not necessarily relate to any specific
GT (primary or media) that we might be dealing with interrupts for.
Reworking the driver's MMIO handling to not be dependent on xe_gt is
planned as a future patch series.

Note that GT initialization code currently calls xe_gt_irq_postinstall()
in an attempt to enable the HWE interrupts for the GT being initialized.
Unfortunately xe_gt_irq_postinstall() doesn't really match its name and
does a bunch of other stuff unrelated to the GT interrupts (such as
enabling the top-level device interrupts). That will be addressed in
future patches.

v2:
- Clarify commit message with explanation of why DG1_MSTR_TILE_INTR is
only used on the root tile, even though it's an sgunit register that
is technically present in each tile's MMIO space. (Aravind)
- Also clarify that the xe_gt used as a target for MMIO operations may
or may not relate to the GT we're dealing with for interrupts.
(Lucas)

Cc: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
Link: https://lore.kernel.org/r/20230601215244.678611-22-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drm/xe: Introduce a new DRM driver for Intel GPUs

Xe, is a new driver for Intel GPUs that supports both integrated and
discrete platforms starting with Tiger Lake (first Intel Xe Architecture).

The code is at a stage where it is already functional and has experimental
support for multiple platforms starting from Tiger Lake, with initial
support implemented in Mesa (for Iris and Anv, our OpenGL and Vulkan
drivers), as well as in NEO (for OpenCL and Level0).

The new Xe driver leverages a lot from i915.

As for display, the intent is to share the display code with the i915
driver so that there is maximum reuse there. But it is not added
in this patch.

This initial work is a collaboration of many people and unfortunately
the big squashed patch won't fully honor the proper credits. But let's
get some git quick stats so we can at least try to preserve some of the
credits:

Co-developed-by: Matthew Brost <matthew.brost@intel.com>
Co-developed-by: Matthew Auld <matthew.auld@intel.com>
Co-developed-by: Matt Roper <matthew.d.roper@intel.com>
Co-developed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Co-developed-by: Francois Dugast <francois.dugast@intel.com>
Co-developed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Co-developed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Co-developed-by: Philippe Lecluse <philippe.lecluse@intel.com>
Co-developed-by: Nirmoy Das <nirmoy.das@intel.com>
Co-developed-by: Jani Nikula <jani.nikula@intel.com>
Co-developed-by: José Roberto de Souza <jose.souza@intel.com>
Co-developed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Co-developed-by: Dave Airlie <airlied@redhat.com>
Co-developed-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Co-developed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Co-developed-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>