drm: vkms: Refactor the plane composer to accept new formats

Currently the blend function only accepts XRGB_8888 and ARGB_8888
as a color input.

This patch refactors all the functions related to the plane composition
to overcome this limitation.

The pixels blend is done using the new internal format. And new handlers
are being added to convert a specific format to/from this internal format.

So the blend operation depends on these handlers to convert to this common
format. The blended result, if necessary, is converted to the writeback
buffer format.

This patch introduces three major differences to the blend function.
1 - All the planes are blended at once.
2 - The blend calculus is done as per line instead of per pixel.
3 - It is responsible to calculates the CRC and writing the writeback
buffer(if necessary).

These changes allow us to allocate way less memory in the intermediate
buffer to compute these operations. Because now we don't need to
have the entire intermediate image lines at once, just one line is
enough.

| Memory consumption (output dimensions) |
|:--------------------------------------:|
| Current | This patch |
|:------------------:|:-----------------:|
| Width * Heigth | 2 * Width |

Beyond memory, we also have a minor performance benefit from all
these changes. Results running the IGT[1] test
`igt@kms_cursor_crc@pipe-a-cursor-512x512-onscreen` ten times:

| Frametime |
|:------------------------------------------:|
| Implementation | Current | This commit |
|:---------------:|:---------:|:------------:|
| frametime range | 9~22 ms | 5~17 ms |
| Average | 11.4 ms | 7.8 ms |

[1] IGT commit id: bc3f6833a12221a46659535dac06ebb312490eb4

V2: Improves the performance drastically, by performing the operations
per-line and not per-pixel(Pekka Paalanen).
Minor improvements(Pekka Paalanen).
V3: Changes the code to blend the planes all at once. This improves
performance, memory consumption, and removes much of the weirdness
of the V2(Pekka Paalanen and me).
Minor improvements(Pekka Paalanen and me).
V4: Rebase the code and adapt it to the new NUM_OVERLAY_PLANES constant.
V5: Minor checkpatch fixes and the removal of TO-DO item(Melissa Wen).
Several security/robustness improvents(Pekka Paalanen).
Removes check_planes_x_bounds function and allows partial
partly off-screen(Pekka Paalanen).
V6: Fix a mismatch of some variable sizes (Pekka Paalanen).
Several minor improvements (Pekka Paalanen).

Reviewed-by: Melissa Wen <mwen@igalia.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Igor Torrente <igormtorrente@gmail.com>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220905190811.25024-7-igormtorrente@gmail.com

drm/vkms: Switch to shmem helpers

Inspired by a patch by Chris Wilson for vgem. Plus this gives us vmap
at the gem bo level, which we need for generic fbdev emulation.

Luckily shmem also tracks ->vaddr, so we just need to adjust the code
all over a bit to make this fit.

Also wire up handle_to_fd, dunno why that was missing.

v2:
- Drop now unused container_of #define (Melissa)
- Make sure we keep creating cached objects, this is for testing
(Thomas)

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Melissa Wen <melissa.srw@gmail.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201013111027.375999-1-daniel.vetter@ffwll.ch

drm/vkms: Add support for writeback

This patch implements the necessary functions to add writeback support
for vkms. This feature is useful for testing compositors if you don't
have hardware with writeback support.

Change in V4 (Emil and Melissa):
- Move signal completion above drm_crtc_add_crc_entry()
- Make writeback always available
- Use appropriate namespace
- Drop fb check in vkms_wb_atomic_commit
- Make vkms_set_composer visible for writeback code
- Enable composer operation on prepare_job and disable it on cleanup_job
- Drop extra space at the end of the file
- Rebase

Change in V3 (Daniel):
- If writeback is enabled, compose everything into the writeback buffer
instead of CRC private buffer
- Guarantees that the CRC will match exactly what we have in the
writeback buffer.

Change in V2:
- Rework signal completion (Brian)
- Integrates writeback with active_planes (Daniel)
- Compose cursor (Daniel)

Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200830142000.146706-4-rodrigosiqueiramelo@gmail.com

drm/vkms: Rename vkms_crc.c into vkms_composer.c

As a preparation work for introducing writeback to vkms, this patch
renames the file vkms_crc.c into vkms_composer.c. Accordingly, it also
adjusts the functions and data structures to match the changes.

No functional change.

Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/dea62063077ebf5cc1dfce8876e56788d15367e6.1561491964.git.rodrigosiqueiramelo@gmail.com

treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drm/vkms: Implement CRC debugfs API

This patch implement the necessary functions to compute and add CRCs
entries:

- Implement the set_crc_source() callback.
- Compute CRC using crc32 on the visible part of the framebuffer.
- Use ordered workqueue per output to compute and add CRC at the end
of a vblank.
- Use appropriate synchronization methods since the CRC computation must
be atomic wrt the generated vblank event for a given atomic update, by
using spinlock across atomic_begin/atomic_flush to wrap the event
handling code completely and match the flip event with the CRC.

Since vkms_crc_work_handle() can sleep, spinlock can't be acquired
while accessing vkms_output->primary_crc to compute CRC.
To make sure the data is updated and released without conflict with
the vkms_crc_work_handle(), the work_struct is flushed @crtc_destroy
and the data is updated before scheduling the work handle again, as
follow:

* CRC data update:
1- store vkms_crc_data {fb, src} per plane_state
2- @plane_duplicate_state -> allocate vkms_crc_data
3- during atomic commit (@atomic_update) ->
a) copy {fb, src} to plane_state->crc_data
b) get reference to fb,
3- @plane_destroy_state -> a) if (fb refcount) remove reference to fb
b) deallocate crc_data

* Atomic Commit:
1- vkms_plane_atomic_check
2- vkms_prepare_fb -> vmap vkms_gem_obj->vaddr
3- atomic_begin -> hold crc spinlock
4- atomic_plane_update -> a) update vkms_output->primary_crc
b) get reference to fb
5- atomic_flush -> a) send vblank event while holding event_lock
b) release crc spinlock

* hrtimer regular callback:
1- hold crc spinlock
2- drm_crtc_handle_vblank()
3- queue vkms_crc_work_handle
4- release crc spinlock

* cleanup:
1- @cleanup_fb ->vunmap vkms_gem_obj->vaddr
2- @crtc_destroy -> flush work struct
3- @plane_destroy -> a) if (fb refcount) remove reference to fb
b) deallocate crc_data

Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
[seanpaul fixed typo in vkms_crtc s/vblamk/vblank/]
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/b948327f48c3e70ab232b4a0848ee6d033b26484.1533171495.git.hamohammed.sa@gmail.com

drm/vkms: Add dumb operations

VKMS currently does not handle dumb data, and as a consequence, it does
not provide mechanisms for handling gem. This commit adds the necessary
support for gem object/handler and the dumb functions.

Changes since V1:
Daniel Vetter:
- Add dumb buffer support to the same patchset
Changes since V2:
Haneen:
- Add missing gem_free_object_unlocked callback to fix the warning
"Memory manager not clean during takedown"

Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/70b7becc91c6a323dbc15cb5fc912cbdfe4ef7d9.1531359228.git.rodrigosiqueiramelo@gmail.com

drm/vkms: Add basic CRTC initialization

This commit adds the essential infrastructure for around CRTCs which
is composed of: a new data struct for output data information, a
function for creating planes, and a simple encoder attached to the
connector. Finally, due to the introduction of a new initialization
function, connectors were moved from vkms_drv.c to vkms_display.c.

Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Reviewed-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/b6e27bc6a54f5cb340658fa5969f7b48fbfbf1b7.1526514457.git.rodrigosiqueiramelo@gmail.com

drm/vkms: Introduce basic VKMS driver

This patch introduces Virtual Kernel Mode-Setting (VKMS) driver. It
creates a very basic kms driver with 1 crtc/encoder/connector/plane.

VKMS driver would be useful for testing, or for running X (or similar)
on headless machines and be able to still use the GPU. Thus it enables
a virtual display without the need for hardware display capability.

Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180514143346.GA21695@haneen-vb