drm/nouveau/kms/nvd9-nv138: Fix CRC calculation for the cursor channel

Something that didn't get noticed until I started running cursor tests:
we're accidentally disabling an option for CRC calculation that's enabled
by default: WidePipeCrc, which controls whether we use the full width of
the data in the display pipe in order calculate CRCs. Having this disabled
apparently causes frames with the cursor plane enabled to generate
different CRCs than frames without the cursor plane enabled, even if the
frames are pixel-equivalent.

So, let's make sure to enable this and fix a bunch of cursor related tests
in IGT.

v2:
* Nvidia added the specific bit we were using to fix this issues to
open-gpu-docs, so pull in the actual macro definitions for it

Cc: Martin Peres <martin.peres@free.fr>
Cc: Jeremy Cline <jcline@redhat.com>
Cc: Simon Ser <contact@emersion.fr>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Link: https://gitlab.freedesktop.org/drm/nouveau/-/merge_requests/10

drm/nouveau/kms/nv140-: Use hard-coded wndws or core channel for CRC channel

Originally it was assumed based on Nvidia's open-gpu-docs and testing that
NVDisplay required that at least one wndw which belongs to a given head to
be used as the controlling channel
(NVC37D_HEAD_SET_CRC_CONTROL_CONTROLLING_CHANNEL) in order for CRC capture
to function. While this is the case on Volta, Turing actually adds the
ability to instead use the core channel as the controlling channel. For
Turing this is quite useful, as it means that we can always default to the
core channel as the controlling channel and we don't need to be concerned
about ensuring we have at least one wndw channel owned by a head with CRC
output enabled. While Volta lacks this ability, Volta conveniently also
lacks flexible wndw mapping - meaning that we can always rely on each head
having four wndw channels mapped to it regardless of the atomic state.

So, simply use the hard-coded wndw mappings we're guaranteed to have on
Volta as the controlling channel, and use the core channel as the
controlling channel for Turing+. As a result this also renders the plane
ownership logic in nv50_crc_atomic_check() unnessecary, which gives us one
less thing to implement when we get support for flexible wndw mapping. We
also can entirely drop the wndw parameter from our set_src callbacks, and
the atomic state.

v2 (Karol): put prackets around complex macro definition
removed spaces before :32 in structs

Cc: Martin Peres <martin.peres@free.fr>
Cc: Jeremy Cline <jcline@redhat.com>
Cc: Simon Ser <contact@emersion.fr>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Link: https://gitlab.freedesktop.org/drm/nouveau/-/merge_requests/10

drm/nouveau/kms/nv50-: use NVIDIA's headers for core crc_set_ctx()

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>

drm/nouveau/kms/nv50-: use NVIDIA's headers for core crc_set_src()

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>

drm/nouveau/kms/nv50-: convert core crc_set_ctx() to new push macros

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>

drm/nouveau/kms/nv50-: convert core crc_set_src() to new push macros

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>

drm/nouveau/kms/nvd9-: Add CRC support

This introduces support for CRC readback on gf119+, using the
documentation generously provided to us by Nvidia:

https://github.com/NVIDIA/open-gpu-doc/blob/master/Display-CRC/display-crc.txt

We expose all available CRC sources. SF, SOR, PIOR, and DAC are exposed
through a single set of "outp" sources: outp-active/auto for a CRC of
the scanout region, outp-complete for a CRC of both the scanout and
blanking/sync region combined, and outp-inactive for a CRC of only the
blanking/sync region. For each source, nouveau selects the appropriate
tap point based on the output path in use. We also expose an "rg"
source, which allows for capturing CRCs of the scanout raster before
it's encoded into a video signal in the output path. This tap point is
referred to as the raster generator.

Note that while there's some other neat features that can be used with
CRC capture on nvidia hardware, like capturing from two CRC sources
simultaneously, I couldn't see any usecase for them and did not
implement them.

Nvidia only allows for accessing CRCs through a shared DMA region that
we program through the core EVO/NvDisplay channel which is referred to
as the notifier context. The notifier context is limited to either 255
(for Fermi-Pascal) or 2047 (Volta+) entries to store CRCs in, and
unfortunately the hardware simply drops CRCs and reports an overflow
once all available entries in the notifier context are filled.

Since the DRM CRC API and igt-gpu-tools don't expect there to be a limit
on how many CRCs can be captured, we work around this in nouveau by
allocating two separate notifier contexts for each head instead of one.
We schedule a vblank worker ahead of time so that once we start getting
close to filling up all of the available entries in the notifier
context, we can swap the currently used notifier context out with
another pre-prepared notifier context in a manner similar to page
flipping.

Unfortunately, the hardware only allows us to this by flushing two
separate updates on the core channel: one to release the current
notifier context handle, and one to program the next notifier context's
handle. When the hardware processes the first update, the CRC for the
current frame is lost. However, the second update can be flushed
immediately without waiting for the first to complete so that CRC
generation resumes on the next frame. According to Nvidia's hardware
engineers, there isn't any cleaner way of flipping notifier contexts
that would avoid this.

Since using vblank workers to swap out the notifier context will ensure
we can usually flush both updates to hardware within the timespan of a
single frame, we can also ensure that there will only be exactly one
frame lost between the first and second update being executed by the
hardware. This gives us the guarantee that we're always correctly
matching each CRC entry with it's respective frame even after a context
flip. And since IGT will retrieve the CRC entry for a frame by waiting
until it receives a CRC for any subsequent frames, this doesn't cause an
issue with any tests and is much simpler than trying to change the
current DRM API to accommodate.

In order to facilitate testing of correct handling of this limitation,
we also expose a debugfs interface to manually control the threshold for
when we start trying to flip the notifier context. We will use this in
igt to trigger a context flip for testing purposes without needing to
wait for the notifier to completely fill up. This threshold is reset
to the default value set by nouveau after each capture, and is exposed
in a separate folder within each CRTC's debugfs directory labelled
"nv_crc".

Changes since v1:
* Forgot to finish saving crc.h before saving, whoops. This just adds
some corrections to the empty function declarations that we use if
CONFIG_DEBUG_FS isn't enabled.
Changes since v2:
* Don't check return code from debugfs_create_dir() or
debugfs_create_file() - Greg K-H
Changes since v3:
(no functional changes)
* Fix SPDX license identifiers (checkpatch)
* s/uint32_t/u32/ (checkpatch)
* Fix indenting in switch cases (checkpatch)
Changes since v4:
* Remove unneeded param changes with nv50_head_flush_clr/set
* Rebase
Changes since v5:
* Remove set but unused variable (outp) in nv50_crc_atomic_check() -
Kbuild bot

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200627194657.156514-10-lyude@redhat.com