[PATCH v3 0/4] drm/v3d: add multiple in/out syncobjs support

[Melissa Wen]

Currently, v3d only supports single in/out syncobj per submission (in
v3d_submit_cl, there are two in_sync, one for bin and another for render
job); however, Vulkan queue submit operations expect multiples wait and
signal semaphores. This series extends v3d interface and job dependency
operations to handle more than one in/out syncobj.

The first patch just decouples the steps to lookup and add job
dependency from the job init code, since the operation repeats for every
syncobj that a job should wait before starting. So, the fourth patch of
this series will reuse it to handle multiples wait for semaphores.

The second patch moves job memory allocation to v3d_job_init() for any
type of v3d_job-based job. The main goal is to prevent errors when
handling job initialization failures (doing a proper cleanup). 

The third patch extends our interface by using a generic extension.
This approach was inspired by i915_user_extension[1] and
amd_cs_chunks[2] to give a little more flexibility in adding other
submission features in the future. Therefore, the list of extensions
would work as a hub of features that use an id to determine the
corresponding feature data type.

With this base, the fourth patch adds multiple wait/signal semaphores
support. For this, we add to the list of the generic extensions a new
data type (drm_v3d_multi_sync) that points to two arrays of syncobjs
(in/out) and also determines (wait_stage) the job to add wait
dependencies (v3d_queue). An auxiliary struct (v3d_submit_ext) is used
when parsing submission extensions. Finally, we reserve some space in
the semaphore struct (drm_v3d_sem) to accommodate timeline semaphores
that we aim to add support soon (same reason for already defining
v3d_submit_outsync).

[1] https://cgit.freedesktop.org/drm/drm-misc/commit/drivers/gpu/drm/i915/i915_user_extensions.c?id=9d1305ef80b95dde0337106ed8b826604e2155ad
[2] https://cgit.freedesktop.org/drm/drm-misc/tree/include/uapi/drm/amdgpu_drm.h#n556

In the mesa side, the work related to this series is in progress at
https://gitlab.freedesktop.org/mwen/mesa/-/commit/6c340bb35203a0418af87a7921d7295a4047b77f

v2:
- move job mem alloc to v3d_job_init (Iago)
- simplify and subclass the generic extension struct (Daniel)
- make job dependency conditions more understandable (Iago)

v3 (Iago):
- job should be initialized NULL
- fix error handling for pm ops in v3d_job_init
- remove irrelevant comment
- fix multisync conditions to multiple vs single sempahores

Melissa Wen (4):
  drm/v3d: decouple adding job dependencies steps from job init
  drm/v3d: alloc and init job in one shot
  drm/v3d: add generic ioctl extension
  drm/v3d: add multiple syncobjs support

 drivers/gpu/drm/v3d/v3d_drv.c |  10 +-
 drivers/gpu/drm/v3d/v3d_drv.h |  24 ++-
 drivers/gpu/drm/v3d/v3d_gem.c | 390 +++++++++++++++++++++++++---------
 include/uapi/drm/v3d_drm.h    |  78 +++++++
 4 files changed, 389 insertions(+), 113 deletions(-)

-- 
2.30.2

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