drm/i915/gt: Rename dev_priv to i915 for private data naming consistency

It has become common practice to refer to the drm_i915_private
structures as "i915". However, there are still instances where
they are referred to as "dev_priv". This inconsistency can make
grepping for information more difficult and does not maintain a
cohesive style throughout the code.

Rename all the "dev_priv" structures in the gt/* directory to
"i915".

Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230210150344.1066991-1-andi.shyti@linux.intel.com

drm/i915/rps: Centralize computation of freq caps

Freq caps (i.e. RP0, RP1 and RPn frequencies) are read from HW. However the
formats (bit positions, widths, registers and units) of these vary for
different generations with even more variations arriving in the future. In
order not to have to do identical computation for these caps in multiple
places, here we centralize the computation of these caps. This makes the
code cleaner and also more extensible for the future.

v2: Clarify that caps are in "hw units" in comments (Lucas De Marchi)
v3: Minor checkpatch fix
v4: s/intel_rps_get_freq_caps/gen6_rps_get_freq_caps/ (Badal Nilawar)
v5: Changes comments to kernel doc (Anshuman Gupta)

Cc: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Badal Nilawar <badal.nilawar@intel.com>
Acked-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220406191848.20895-1-ashutosh.dixit@intel.com

drm/i915/gt: SPDX cleanup

Clean up the SPDX licence declarations to comply with checkpatch.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210122192913.4518-1-chris@chris-wilson.co.uk
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drm/i915: Drop i915_request.lock requirement for intel_rps_boost()

Since we use a flag within i915_request.flags to indicate when we have
boosted the request (so that we only apply the boost) once, this can be
used as the serialisation with i915_request_retire() to avoid having to
explicitly take the i915_request.lock which is more heavily contended.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201231093149.19086-1-chris@chris-wilson.co.uk

drm/i915/gt: Switch to manual evaluation of RPS

As with the realisation for soft-rc6, we respond to idling the engines
within microseconds, far faster than the response times for HW RC6 and
RPS. Furthermore, our fast parking upon idle, prevents HW RPS from
running for many desktop workloads, as the RPS evaluation intervals are
on the order of tens of milliseconds, but the typical workload is just a
couple of milliseconds, but yet we still need to determine the best
frequency for user latency versus power.

Recognising that the HW evaluation intervals are a poor fit, and that
they were deprecated [in bspec at least] from gen10, start to wean
ourselves off them and replace the EI with a timer and our accurate
busy-stats. The principle benefit of manually evaluating RPS intervals
is that we can be more responsive for better performance and powersaving
for both spiky workloads and steady-state.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1698
Fixes: 98479ada421a ("drm/i915/gt: Treat idling as a RPS downclock event")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200429205446.3259-4-chris@chris-wilson.co.uk

drm/i915/gt: Track use of RPS interrupts in flags

Use the new intel_rps.flags field to store whether or not interrupts are
being used with RPS.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi@etezian.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200429205446.3259-3-chris@chris-wilson.co.uk

drm/i915/gt: Move rps.enabled/active to flags

Pull the boolean intel_rps.enabled and intel_rps.active into a single
flags field, in preparation for more.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200429205446.3259-2-chris@chris-wilson.co.uk

drm/i915: Extract GT render power state management

i915_irq.c is large. One reason for this is that has a large chunk of
the GT render power management stashed away in it. Extract that logic
out of i915_irq.c and intel_pm.c and put it under one roof.

Based on a patch by Chris Wilson.

Signed-off-by: Andi Shyti <andi.shyti@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191024211642.7688-1-chris@chris-wilson.co.uk