Re: [PATCH v2 0/3] media: pci: intel: ivsc: Add driver of Intel Visual Sensing Controller(IVSC)
From: Pandruvada, Srinivas
Date: Sun Feb 12 2023 - 22:21:23 EST
On Mon, 2023-02-13 at 10:23 +0800, Wentong Wu wrote:
>
v2 without change log, why?
> Intel Visual Sensing Controller (IVSC), codenamed "Clover Falls", is
> a
> companion chip designed to provide secure and low power vision
> capability
> to IA platforms. IVSC is available in existing commercial platforms
> from
> multiple OEMs.
>
> The primary use case of IVSC is to bring in context awareness. IVSC
> interfaces directly with the platform main camera sensor via a CSI-2
> link
> and processes the image data with the embedded AI engine. The
> detected
> events are sent over I2C to ISH (Intel Sensor Hub) for additional
> data
> fusion from multiple sensors. The fusion results are used to
> implement
> advanced use cases like:
> - Face detection to unlock screen
> - Detect user presence to manage backlight setting or waking up
> system
>
> Since the Image Processing Unit(IPU) used on the host processor needs
> to
> configure the CSI-2 link in normal camera usages, the CSI-2 link and
> camera sensor can only be used in mutually-exclusive ways by host IPU
> and
> IVSC. By default the IVSC owns the CSI-2 link and camera sensor. The
> IPU
> driver can take ownership of the CSI-2 link and camera sensor using
> interfaces provided by this IVSC driver.
>
> Switching ownership requires an interface with two different hardware
> modules inside IVSC. The software interface to these modules is via
> Intel
> MEI (The Intel Management Engine) commands. These two hardware
> modules
> have two different MEI UUIDs to enumerate. These hardware modules
> are:
> - ACE (Algorithm Context Engine): This module is for algorithm
> computing
> when IVSC owns camera sensor. Also ACE module controls camera
> sensor's
> ownership. This hardware module is used to set ownership of camera
> sensor.
> - CSI (Camera Serial Interface): This module is used to route camera
> sensor data either to IVSC or to host for IPU driver and application.
>
> IVSC also provides a privacy mode. When privacy mode is turned on,
> camera sensor can't be used. This means that both ACE and host IPU
> can't
> get image data. And when this mode is turned on, host IPU driver is
> informed via a registered callback, so that user can be notified.
>
> In summary, to acquire ownership of camera by IPU driver, first ACE
> module needs to be informed of ownership and then to setup MIPI CSI-2
> link for the camera sensor and IPU.
>
> Implementation:
> There are two different drivers to handle ACE and CSI hardware
> modules
> inside IVSC.
> - mei_csi: MEI client driver to send commands and receive
> notifications
> from CSI module.
> - mei_ace: MEI client driver to send commands and get status from
> ACE
> module.
> Interface is exposed via ivsc.h to acquire and release camera sensor
> and
> CSI-2 link.
>
> Below diagram shows connections of IVSC/ISH/IPU/Camera sensor.
> ---------------------------------------------------------------------
> --------
> > Host
> > Processor
> > |
> >
> > |
> > ----------------- ----------------- -------------
> > -- |
> > | | | | |
> > | I2C |
> > | IPU | | ISH | |camera
> > driver|--| |
> > | | | | |
> > | | |
> > ----------------- ----------------- -------------
> > -- | |
> > | |
> > | | |
> > | | -------------
> > -- | |
> > | | |
> > | | |
> > | | | IVSC driver
> > | | |
> > | | |
> > | | |
> > | | -------------
> > -- | |
> > | |
> > | | |
> ----------------|-----------------------|----------------------|-----
> ----|---
> | CSI | I2C
> |SPI |
> | |
> | |
> ----------------|-----------------------|----------------
> | |
> > IVSC | |
> > | |
> > | |
> > | |
> > ----------------- ----------------- |
> > | |
> > | | | | |
> > | |
> > | CSI | | ACE | |------
> > | |
> > | | | |
> > | |
> > ----------------- -----------------
> > | |
> > | | I2C
> > | |
> ----------------|-----------------------|----------------
> |
> | CSI
> | |
> |
> | |
> --------------------------------
> |
> | |
> I2C |
> | camera sensor |-------------------------
> ----|
> | |
> --------------------------------
>
> Wentong Wu (3):
> media: pci: intel: ivsc: Add CSI submodule
> media: pci: intel: ivsc: Add ACE submodule
> media: pci: intel: ivsc: Add acquire/release API for ivsc
>
> drivers/media/pci/Kconfig | 1 +
> drivers/media/pci/intel/Makefile | 2 +
> drivers/media/pci/intel/ivsc/Kconfig | 12 +
> drivers/media/pci/intel/ivsc/Makefile | 7 +
> drivers/media/pci/intel/ivsc/ivsc.c | 84 +++++
> drivers/media/pci/intel/ivsc/mei_ace.c | 472
> +++++++++++++++++++++++++
> drivers/media/pci/intel/ivsc/mei_ace.h | 36 ++
> drivers/media/pci/intel/ivsc/mei_csi.c | 342 ++++++++++++++++++
> drivers/media/pci/intel/ivsc/mei_csi.h | 60 ++++
> include/linux/ivsc.h | 74 ++++
> 10 files changed, 1090 insertions(+)
> create mode 100644 drivers/media/pci/intel/ivsc/Kconfig
> create mode 100644 drivers/media/pci/intel/ivsc/Makefile
> create mode 100644 drivers/media/pci/intel/ivsc/ivsc.c
> create mode 100644 drivers/media/pci/intel/ivsc/mei_ace.c
> create mode 100644 drivers/media/pci/intel/ivsc/mei_ace.h
> create mode 100644 drivers/media/pci/intel/ivsc/mei_csi.c
> create mode 100644 drivers/media/pci/intel/ivsc/mei_csi.h
> create mode 100644 include/linux/ivsc.h
>