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[0/3] media: venus: Provide support for selecting encoder/decoder from in-driver

Message ID 20241127-media-staging-24-11-25-rb3-hw-compat-string-v1-0-99c16f266b46@linaro.org
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Series media: venus: Provide support for selecting encoder/decoder from in-driver | expand

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Bryan O'Donoghue Nov. 27, 2024, 1:34 a.m. UTC 
Various venus patches have been held up due to the misuse of DT to provide
a configuration input to venus as to which mode a given transcoder should
be in.

Link: https://lore.kernel.org/linux-arm-msm/436145fd-d65f-44ec-b950-c434775187ca@kernel.org
Link: https://lore.kernel.org/linux-media/ba40de82-b308-67b1-5751-bb2d95f2b8a5@linaro.org/

This series provides support for static configuration of venus from the resource
structure via:

1. Adding two strings to the resource structure.
   One string for the decoder one for the encoder.
2. The string for each SoC has been matched to the existing in the
   DT which currently specifies the mode as decoder or encoder.
3. New logic in the driver parses the DTB looking for the node name
   specified for the decoder and encoder .
4. If the DTB contains the node name, then no new node is added as
   we assume to be working with an "old" DTB.
5. If the DTB does not contain the specified decoder/encoder string
   then a new in-memory node is added which contains a compat string
   consistent with upstream compat strings used to currently select
   between the decoder and encoder respectively.
6. In this way new venus driver entries may be added which respect
   the requirement to move mode selection out of DTB and into driver.
7. Simple instances of decoder/encoder nodes in the yaml schema have been
   marked as deprecated.
8. Since the proposed scheme here always defers to what the DTB says that
   means it would be possible to remove decoder/encoder entries for the
   deprecated schema should we choose to do so at a later date but,
   that step is not taken in this series.
9. Some of the upstream encoder/decoder nodes for example sdm630/sdm660
   also contain clock and power-domain information and have not been
   updated with the static configuration data or had the schema amended to
   deprecate values. Because these nodes impart hardware specific
   information and are already upstream this series proposes to leave
   those as-is.

However if this scheme is adopted it should allow for addition of venus for
both qcs615[1] and sc8280xp[2].

Other SoCs such as sm8550, sm8650 and beyond are expected to be supported
by Iris.

The sm8350 and sm8280xp in the second series would then be able to excise
the offending compat = "video-encoder" | "video-decoder" in the schema and
DT.

I considered making this series an all singing all dancing method to select
between encoder and decoder for all SoCs but, the objective here is not to
add functionality but to provide support for configuration in-driver
consistent with current usage and to do so with a minimal code
intervention.

So far I've tested on RB3 by removing:

video-core0 {
	compatible = "venus-decoder";
};

video-core1 {
	compatible = "venus-encoder";
};

This works - the code adds the nodes into memory and the video
encoder/decoder logic in the plaform code runs.

Similarly if the nodes are left in-place then no new nodes are added by the
code in this series and still both encoder and decoder probe.

Thus proving the code works and will provide support for new platforms
while also leaving open the option of dropping nodes from upstream.

I've left the dropping step out for now, it can be implemented later.

[1] https://lore.kernel.org/linux-arm-msm/20241125-add-venus-for-qcs615-v3-0-5a376b97a68e@quicinc.com
[2] https://lore.kernel.org/linux-media/20230731-topic-8280_venus-v1-0-8c8bbe1983a5@linaro.org/

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
---
Bryan O'Donoghue (3):
      media: venus: Add support for static video encoder/decoder declarations
      media: venus: Populate video encoder/decoder nodename entries
      media: dt-bindings: qcom-venus: Deprecate video-decoder and video-encoder where applicable

 .../bindings/media/qcom,msm8916-venus.yaml         | 12 +---
 .../bindings/media/qcom,sc7180-venus.yaml          | 12 +---
 .../bindings/media/qcom,sc7280-venus.yaml          | 12 +---
 .../bindings/media/qcom,sdm845-venus-v2.yaml       | 12 +---
 .../bindings/media/qcom,sm8250-venus.yaml          | 12 +---
 drivers/media/platform/qcom/venus/core.c           | 67 ++++++++++++++++++++++
 drivers/media/platform/qcom/venus/core.h           |  2 +
 7 files changed, 79 insertions(+), 50 deletions(-)
---
base-commit: 72ad4ff638047bbbdf3232178fea4bec1f429319
change-id: 20241127-media-staging-24-11-25-rb3-hw-compat-string-ea3c99938021

Best regards,