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 | 341 ++++++++++++++++++
drivers/media/pci/intel/ivsc/mei_csi.h | 60 ++++
include/linux/ivsc.h | 74 ++++
10 files changed, 1089 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
--
2.25.1
