drm/i915/dsb: Use DEwake to combat PkgC latency

Normally we could be in a deep PkgC state all the way up to the
point when DSB starts its execution at the transcoders undelayed
vblank. The DSB will then have to wait for the hardware to
wake up before it can execute anything. This will waste a huge
chunk of the vblank time just waiting, and risks the DSB execution
spilling into the vertical active period. That will be very bad,
especially when programming the LUTs as the anti-collision logic
will cause DSB to corrupt LUT writes during vertical active.

To avoid these problems we can instruct the DSB to pre-wake the
display engine on a specific scanline so that everything will
be 100% ready to go when we hit the transcoder's undelayed vblank.

One annoyance is that the scanline is specified as just that,
a single scanline. So if we happen to start the DSB execution
after passing said scanline no DEwake will happen and we may drop
back into some PkgC state before reaching the transcoder's undelayed
vblank. To prevent that we'll use the "force DEwake" bit to manually
force the display engine to stay awake. We'll then have to clear
the force bit again after the DSB is done (the force bit remains
effective even when the DSB is otherwise disabled).

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230606191504.18099-18-ville.syrjala@linux.intel.com
Reviewed-by: Uma Shankar <uma.shankar@intel.com>

drm/i915/dsb: Add support for non-posted DSB registers writes

Writing specific transcoder registers (and as it turns out, the
legacy LUT as well) via DSB needs a magic sequence to emit
non-posted register writes. Add a helper for this.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230606191504.18099-11-ville.syrjala@linux.intel.com
Reviewed-by: Uma Shankar <uma.shankar@intel.com>

drm/i915/dsb: Introduce intel_dsb_reg_write_masked()

Add a function for emitting masked register writes.

Note that the mask is implemented through byte enables,
so can only mask off aligned 8bit sets of bits.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230606191504.18099-10-ville.syrjala@linux.intel.com
Reviewed-by: Uma Shankar <uma.shankar@intel.com>

drm/i915/dsb: Introduce intel_dsb_noop()

Add a helper for emitting a number of DSB NOOPs commands.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230606191504.18099-9-ville.syrjala@linux.intel.com
Reviewed-by: Uma Shankar <uma.shankar@intel.com>

drm/i915/dsb: Allow vblank synchronized DSB execution

Allow the caller to ask for the DSB commands to execute
during vblank.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230118163040.29808-7-ville.syrjala@linux.intel.com
Reviewed-by: Animesh Manna <animesh.manna@intel.com>

drm/i915/dsb: Introduce intel_dsb_finish()

Introduce a function to emits whatever commands we need
at the end of the DSB command buffer. For the moment we
only do the tail cacheline alignment there, but eventually
we might want to eg. emit an interrupt.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230118163040.29808-5-ville.syrjala@linux.intel.com
Reviewed-by: Animesh Manna <animesh.manna@intel.com>

drm/i915/dsb: Split intel_dsb_wait() from intel_dsb_commit()

Starting the DSB execution vs. waiting for it stop are two
totally different things. Split intel_dsb_wait() from
intel_dsb_commit() so that we can eventually allow the DSB
to execute asynchronously.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230118163040.29808-4-ville.syrjala@linux.intel.com
Reviewed-by: Animesh Manna <animesh.manna@intel.com>

drm/i915/dsb: Allow the caller to pass in the DSB buffer size

The caller should more or less know how many DSB commands it
wants to emit into the command buffer, so allow it to specify
the size of the command buffer rather than having the low level
DSB code guess it.

Technically we can emit as many as 134+1033 (for adl+ degamma +
10bit gamma) register writes but thanks to the DSB indexed register
write command we get significant space savings so the current size
estimate of 8KiB (~1024 DSB commands) is sufficient for now.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221216003810.13338-11-ville.syrjala@linux.intel.com
Reviewed-by: Animesh Manna <animesh.manna@intel.com>

drm/i915/dsb: Handle the indexed vs. not inside the DSB code

The DSB indexed register write insturction is purely an internal
DSB implementation detail, no reason why the caller should have to
know about it. So let's just have the caller emit blind register
writes let the DSB code convert things to an indexed write if/when
multiple writes occur to the same register offset in a row.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221216003810.13338-9-ville.syrjala@linux.intel.com
Reviewed-by: Animesh Manna <animesh.manna@intel.com>

drm/i915: Make DSB lower level

We could have many different uses for the DSB(s) during a
single commit, so the current approach of passing the whole
crtc_state to the DSB functions is far too high level. Lower
the abstraction a little bit so each DSB user can decide where
to stick the command buffer/etc.

v2: Document the intel_dsb_prepare() return value (Ankit)

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221123152638.20622-10-ville.syrjala@linux.intel.com
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>

drm/i915/dsb: hide struct intel_dsb better

struct intel_dsb can be an opaque type, hidden in intel_dsb.c. Make it
so. Reduce related includes while at it.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220908165702.973854-1-jani.nikula@intel.com

drm/i915: Only include i915_reg.h from .c files

Several of our i915 header files, have been including i915_reg.h. This
means that any change to i915_reg.h will trigger a full rebuild of
pretty much every file of the driver, even those that don't have any
kind of register access. Let's delete the i915_reg.h include from all
headers and add an explicit include from the .c files that truly
need the register definitions; those that need a definition of
i915_reg_t for a function definition can get it from i915_reg_defs.h
instead.

We also remove two non-register #define's (VLV_DISPLAY_BASE and
GEN12_SFC_DONE_MAX) into i915_reg_defs.h to allow us to drop the
i915_reg.h include from a couple of headers.

There's probably a lot more header dependency optimization possible, but
the changes here roughly cut the number of files compiled after 'touch
i915_reg.h' in half --- a good first step.

Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220127234334.4016964-7-matthew.d.roper@intel.com

drm/i915/dsb: Pre allocate and late cleanup of cmd buffer

Pre-allocate command buffer in atomic_commit using intel_dsb_prepare
function which also includes pinning and map in cpu domain.

No functional change is dsb write/commit functions.

Now dsb get/put function is removed and ref-count mechanism is
not needed. Below dsb api added to do respective job mentioned
below.

intel_dsb_prepare - Allocate, pin and map the buffer.
intel_dsb_cleanup - Unpin and release the gem object.

RFC: Initial patch for design review.
v2: included _init() part in _prepare(). [Daniel, Ville]
v3: dsb_cleanup called after cleanup_planes. [Daniel]
v4: dsb structure is moved to intel_crtc_state from intel_crtc. [Maarten]
v5: dsb get/put/ref-count mechanism removed. [Maarten]
v6: Based on review feedback following changes are added,
- replaced intel_dsb structure by pointer in intel_crtc_state. [Maarten]
- passing intel_crtc_state to dsp-api to simplify the code. [Maarten]
- few dsb functions prototype modified to simplify code.
v7: added few cosmetic changes suggested by Jani and null check for
crtc_state in dsb_cleanup removed as suggested by Maarten.
v8: changed the function parameter to intel_crtc_state* of
ivb_load_lut_ext_max() from intel_crtc. [Maarten]
v9: error handling improved in _write() and prepare(). [Maarten]

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200520130737.11240-1-animesh.manna@intel.com

drm/i915/dsb: remove atomic operations

The current dsb API is not really prepared to handle multithread access.
I was debugging an issue that ended up fixed by commit a096883dda2c
("drm/i915/dsb: Remove PIN_MAPPABLE from the DSB object VMA") and was
puzzled how these atomic operations were guaranteeing atomicity.

if (atomic_add_return(1, &dsb->refcount) != 1)
return dsb;

Thread A could still be initializing dsb struct (and even fail in the
middle) while thread B would take a reference and use it (even
derefencing a NULL cmd_buf).

I don't think the atomic operations here will help much if this were
to support multithreaded scenario in future, so just remove them to
avoid confusion.

v2: Use refcount++ != 0 instead of ++refcount != 1 (from Ville)

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191111205024.22853-2-lucas.demarchi@intel.com
Link: https://patchwork.freedesktop.org/patch/msgid/20191116011539.18230-1-lucas.demarchi@intel.com

drm/i915/dsb: function to trigger workload execution of DSB.

Batch buffer will be created through dsb-reg-write function which can have
single/multiple request based on usecase and once the buffer is ready
commit function will trigger the execution of the batch buffer. All
the registers will be updated simultaneously.

v1: Initial version.
v2: Optimized code few places. (Chris)
v3: USed DRM_ERROR for dsb head/tail programming failure. (Shashank)
v4: reset ins_start_offset after commit. (Jani)

Cc: Imre Deak <imre.deak@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Shashank Sharma <shashank.sharma@intel.com>
Reviewed-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190920115930.27829-8-animesh.manna@intel.com

drm/i915/dsb: Indexed register write function for DSB.

DSB can program large set of data through indexed register write
(opcode 0x9) in one shot. DSB feature can be used for bulk register
programming e.g. gamma lut programming, HDR meta data programming.

v1: initial version.
v2: simplified code by using ALIGN(). (Chris)
v3: ascii table added as code comment. (Shashank)
v4: cosmetic changes done. (Shashank)
v5: reset ins_start_offset. (Jani)
v6: update ins_start_offset in inel_dsb_reg_write.

Cc: Shashank Sharma <shashank.sharma@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190920115930.27829-5-animesh.manna@intel.com

drm/i915/dsb: single register write function for DSB.

DSB support single register write through opcode 0x1. Generic
api created which accumulate all single register write in a batch
buffer and once DSB is triggered, it will program all the registers
at the same time.

v1: Initial version.
v2: Unused macro removed and cosmetic changes done. (Shashank)
v3: set free_pos to zero in dsb-put() instead dsb-get() and
a cosmetic change. (Shashank)
v4: macro of indexed-write is moved. (Shashank)

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Shashank Sharma <shashank.sharma@intel.com>
Reviewed-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190920115930.27829-4-animesh.manna@intel.com

drm/i915/dsb: DSB context creation.

This patch adds a function, which will internally get the gem buffer
for DSB engine. The GEM buffer is from global GTT, and is mapped into
CPU domain, contains the data + opcode to be feed to DSB engine.

v1: Initial version.

v2:
- removed some unwanted code. (Chris)
- Used i915_gem_object_create_internal instead of _shmem. (Chris)
- cmd_buf_tail removed and can be derived through vma object. (Chris)

v3: vma realeased if i915_gem_object_pin_map() failed. (Shashank)

v4: for simplification and based on current usage added single dsb
object in intel_crtc. (Shashank)

v5: seting NULL to cmd_buf moved outside of mutex in dsb-put(). (Shashank)

v6:
- refcount machanism added.
- Used atomic_add_return and atomic_dec_and_test instead of
atomic_inc and atomic_dec. (Jani)

Cc: Imre Deak <imre.deak@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
[Jani: added #include <linux/types.h> while pushing]
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190920115930.27829-3-animesh.manna@intel.com