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[v2,0/4] Enable shared SE support over I2C

Message ID 20240906191438.4104329-1-quic_msavaliy@quicinc.com
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Series Enable shared SE support over I2C | expand

Message

Mukesh Kumar Savaliya Sept. 6, 2024, 7:14 p.m. UTC 
This Series adds support to share QUP (Qualcomm Unified peripheral)
based I2C SE (Serial Engine) controller between two subsystems.
Each subsystem should have its own dedicated GPII (General Purpose -
Interface Instance) acting as pipe between SE and GSI (Generic SW -
Interface) DMA HW engine.

Subsystem must acquire Lock over the SE so that it gets uninterrupted
control till it unlocks the SE. It also makes sure the commonly shared
TLMM GPIOs are not touched which can impact other subsystem or cause
any interruption. Generally, GPIOs are being unconfigured during
suspend time.

GSI DMA engine is capable to perform requested transfer operations
from any of the I2C client in a seamless way and its transparent to
the subsystems. Make sure to enable “qcom,shared-se” flag only while
enabling this feature. I2C client should add in its respective parent
node.

Example : 
Two clients from different SS can share an I2C SE for same slave device
OR their owned slave devices.
Assume I2C Slave EEPROM device connected with I2C controller.
Each client from ADSP SS and APPS Linux SS can perform i2c transactions.
This gets serialized by lock TRE + DMA Transfers + Unlock TRE at HW level.


Signed-off-by: Mukesh Kumar Savaliya <quic_msavaliy@quicinc.com>
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Link to V1: https://lore.kernel.org/lkml/cb7613d0-586e-4089-a1b6-2405f4dc4883@quicinc.com/T/

Changes in V2:
 - Enhanced commit log grammatically for PATCH v1 3/4 as suggested by Bryan.
 - Updated Cover letter along with acronyms expansion.
 - Added maintainers list from other subsystems for review, which was missing.
   Thanks to Krzysztof for pointing out.
 - Added cover letter with an example of Serial Engine sharing.
 - Addressed review comments for all the patches.

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Mukesh Kumar Savaliya (4):
  dt-bindindgs: i2c: qcom,i2c-geni: Document shared flag
  dma: gpi: Add Lock and Unlock TRE support to access SE exclusively
  soc: qcom: geni-se: Export function geni_se_clks_off()
  i2c: i2c-qcom-geni: Enable i2c controller sharing between two
    subsystems

 .../bindings/i2c/qcom,i2c-geni-qcom.yaml      |  4 ++
 drivers/dma/qcom/gpi.c                        | 37 ++++++++++++++++++-
 drivers/i2c/busses/i2c-qcom-geni.c            | 29 +++++++++++----
 drivers/soc/qcom/qcom-geni-se.c               |  4 +-
 include/linux/dma/qcom-gpi-dma.h              |  6 +++
 include/linux/soc/qcom/geni-se.h              |  3 ++
 6 files changed, 74 insertions(+), 9 deletions(-)