drm: introduce drm_writeback_connector_init_with_encoder() API

For vendors drivers which pass an already allocated and
initialized encoder especially for cases where the encoder
hardware is shared OR the writeback encoder shares the resources
with the rest of the display pipeline introduce a new API,
drm_writeback_connector_init_with_encoder() which expects
an initialized encoder as a parameter and only sets up the
writeback connector.

changes in v5:
- fix the encoder doc to indicate that its not valid for
users of drm_writeback_connector_init_with_encoder()

Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Patchwork: https://patchwork.freedesktop.org/patch/483500/
Link: https://lore.kernel.org/r/1650984096-9964-3-git-send-email-quic_abhinavk@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drm: allow passing possible_crtcs to drm_writeback_connector_init()

Clients of drm_writeback_connector_init() initialize the
possible_crtcs and then invoke the call to this API.

To simplify things, allow passing possible_crtcs as a parameter
to drm_writeback_connector_init() and make changes to the
other drm drivers to make them compatible with this change.

changes in v2:
- split the changes according to their functionality

changes in v3:
- allow passing possible_crtcs for existing users of
drm_writeback_connector_init()
- squash the vendor changes into the same commit so
that each patch in the series can compile individually

changes in v4:
- keep only changes related to possible_crtcs
- add line breaks after ARRAY_SIZE
- stop using temporary variables for possible_crtcs

changes in v5:
- None

changes in v6:
- None

changes in v7:
- wrap long lines to match the coding style of existing drivers
- Fix indentation and remove parenthesis where not needed
- use u32 instead of uint32_t for possible_crtcs

Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Patchwork: https://patchwork.freedesktop.org/patch/483501/
Link: https://lore.kernel.org/r/1650984096-9964-2-git-send-email-quic_abhinavk@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drm/writeback: wire drm_writeback.h to kernel-doc

drm_writeback.h included a lot of nice kernel-doc comments.
Wire it up so the header file is included in the kernel-doc
generated documentation.

Added a few simple comments to the two structs so they
get picked up by kernel-doc.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: Brian Starkey <brian.starkey@arm.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200406194746.26433-4-sam@ravnborg.org

drm: writeback: Add job prepare and cleanup operations

As writeback jobs contain a framebuffer, drivers may need to prepare and
cleanup them the same way they can prepare and cleanup framebuffers for
planes. Add two new optional connector helper operations,
.prepare_writeback_job() and .cleanup_writeback_job() to support this.

The job prepare operation is called from
drm_atomic_helper_prepare_planes() to avoid a new atomic commit helper
that would need to be called by all drivers not using
drm_atomic_helper_commit(). The job cleanup operation is called from the
existing drm_writeback_cleanup_job() function, invoked both when
destroying the job as part of a aborted commit, or when the job
completes.

The drm_writeback_job structure is extended with a priv field to let
drivers store per-job data, such as mappings related to the writeback
framebuffer.

For internal plumbing reasons the drm_writeback_job structure needs to
store a back-pointer to the drm_writeback_connector. To avoid pushing
too much writeback-specific knowledge to drm_atomic_uapi.c, create a
drm_writeback_set_fb() function, move the writeback job setup code
there, and set the connector backpointer. The prepare_signaling()
function doesn't need to allocate writeback jobs and can ignore
connectors without a job, as it is called after the writeback jobs are
allocated to store framebuffers, and a writeback fence with a
framebuffer is an invalid configuration that gets rejected by the commit
check.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>

drm: writeback: Cleanup job ownership handling when queuing job

The drm_writeback_queue_job() function takes ownership of the passed job
and requires the caller to manually set the connector state
writeback_job pointer to NULL. To simplify drivers and avoid errors
(such as the missing NULL set in the vc4 driver), pass the connector
state pointer to the function instead of the job pointer, and set the
writeback_job pointer to NULL internally.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Brian Starkey <brian.starkey@arm.com>
Acked-by: Eric Anholt <eric@anholt.net>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>

drm/atomic: Avoid connector to writeback_connector casts

Use container_of() instead of type casting so that it keeps working
even if base is moved inside the drm_writeback_connector struct.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180703075022.15138-2-boris.brezillon@bootlin.com

drm: writeback: Add out-fences for writeback connectors

Add the WRITEBACK_OUT_FENCE_PTR property to writeback connectors, to
enable userspace to get a fence which will signal once the writeback is
complete. It is not allowed to request an out-fence without a
framebuffer attached to the connector.

A timeline is added to drm_writeback_connector for use by the writeback
out-fences.

In the case of a commit failure or DRM_MODE_ATOMIC_TEST_ONLY, the fence
is set to -1.

Changes from v2:
- Rebase onto Gustavo Padovan's v9 explicit sync series
- Change out_fence_ptr type to s32 __user *
- Set *out_fence_ptr to -1 in drm_atomic_connector_set_property
- Store fence in drm_writeback_job
Gustavo Padovan:
- Move out_fence_ptr out of connector_state
- Signal fence from drm_writeback_signal_completion instead of
in driver directly

Changes from v3:
- Rebase onto commit 7e9081c5aac7 ("drm/fence: fix memory overwrite
when setting out_fence fd") (change out_fence_ptr to s32 __user *,
for real this time.)
- Update documentation around WRITEBACK_OUT_FENCE_PTR

Signed-off-by: Brian Starkey <brian.starkey@arm.com>
[rebased and fixed conflicts]
Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/229036/

drm: Add writeback connector type

Writeback connectors represent writeback engines which can write the
CRTC output to a memory framebuffer. Add a writeback connector type and
related support functions.

Drivers should initialize a writeback connector with
drm_writeback_connector_init() which takes care of setting up all the
writeback-specific details on top of the normal functionality of
drm_connector_init().

Writeback connectors have a WRITEBACK_FB_ID property, used to set the
output framebuffer, and a WRITEBACK_PIXEL_FORMATS blob used to expose the
supported writeback formats to userspace.

When a framebuffer is attached to a writeback connector with the
WRITEBACK_FB_ID property, it is used only once (for the commit in which
it was included), and userspace can never read back the value of
WRITEBACK_FB_ID. WRITEBACK_FB_ID can only be set if the connector is
attached to a CRTC.

Changes since v1:
- Added drm_writeback.c + documentation
- Added helper to initialize writeback connector in one go
- Added core checks
- Squashed into a single commit
- Dropped the client cap
- Writeback framebuffers are no longer persistent

Changes since v2:
Daniel Vetter:
- Subclass drm_connector to drm_writeback_connector
- Relax check to allow CRTC to be set without an FB
- Add some writeback_ prefixes
- Drop PIXEL_FORMATS_SIZE property, as it was unnecessary
Gustavo Padovan:
- Add drm_writeback_job to handle writeback signalling centrally

Changes since v3:
- Rebased
- Rename PIXEL_FORMATS -> WRITEBACK_PIXEL_FORMATS

Chances since v4:
- Embed a drm_encoder inside the drm_writeback_connector to
reduce the amount of boilerplate code required from the drivers
that are using it.

Changes since v5:
- Added Rob Clark's atomic_commit() vfunc to connector helper
funcs, so that writeback jobs are committed from atomic helpers
- Updated create_writeback_properties() signature to return an
error code rather than a boolean false for failure.
- Free writeback job with the connector state rather than when
doing the cleanup_work()

Changes since v7:
- fix extraneous use of out_fence that is only introduced in a
subsequent patch.

Changes since v8:
- whitespace changes pull from subsequent patch

Changes since v9:
- Revert the v6 changes that free the writeback job in the connector
state cleanup and return to doing it in the cleanup_work() function

Signed-off-by: Brian Starkey <brian.starkey@arm.com>
[rebased and fixed conflicts]
Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
[rebased and added atomic_commit() vfunc for writeback jobs]
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/229037/