Hi Wentong, On Thu, Mar 30, 2023 at 07:32:27AM +0000, Wu, Wentong wrote: > Hi Sakari, > > Thanks > > > -----Original Message----- > > From: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > > Sent: Wednesday, March 29, 2023 4:04 PM > > > > Hi Wentong, > > > > On Mon, Mar 27, 2023 at 02:23:07PM +0800, Wentong Wu wrote: > > > ACE is a submodule of IVSC which controls camera sensor's ownership, > > > belonging to host or IVSC. When IVSC owns camera sensor, it is for > > > algorithm computing. When host wants to control camera sensor, ACE > > > module needs to be informed of ownership with defined interface. > > > > > > The interface is via MEI. There is a separate MEI UUID, which this > > > driver uses to enumerate. > > > > > > To switch ownership of camera sensor between IVSC and host, the caller > > > specifies the defined ownership information which will be sent to > > > firmware by sending MEI command. > > > > > > Device link(device_link_add) is used to set the right camera sensor > > > ownership before accessing the sensor via I²C. With DL_FLAG_PM_RUNTIME > > > and DL_FLAG_RPM_ACTIVE, the supplier device will be PM runtime resumed > > > before the consumer(camera sensor). > > > So use runtime PM callbacks to transfer the ownership between host and > > > IVSC. > > > > > > Signed-off-by: Wentong Wu <wentong.wu@xxxxxxxxx> > > > --- > > > drivers/media/pci/intel/ivsc/Makefile | 3 + > > > drivers/media/pci/intel/ivsc/mei_ace.c | 534 > > > +++++++++++++++++++++++++++++++++ > > > 2 files changed, 537 insertions(+) > > > create mode 100644 drivers/media/pci/intel/ivsc/mei_ace.c > > > > > > diff --git a/drivers/media/pci/intel/ivsc/Makefile > > > b/drivers/media/pci/intel/ivsc/Makefile > > > index 7e4c5f0..a641f14 100644 > > > --- a/drivers/media/pci/intel/ivsc/Makefile > > > +++ b/drivers/media/pci/intel/ivsc/Makefile > > > @@ -5,3 +5,6 @@ > > > obj-$(CONFIG_INTEL_VSC) += ivsc-csi.o ivsc-csi-y += mei_csi.o > > > ivsc-csi-y += csi_bridge.o > > > + > > > +obj-$(CONFIG_INTEL_VSC) += ivsc-ace.o ivsc-ace-y += mei_ace.o > > > diff --git a/drivers/media/pci/intel/ivsc/mei_ace.c > > > b/drivers/media/pci/intel/ivsc/mei_ace.c > > > new file mode 100644 > > > index 0000000..434b072 > > > --- /dev/null > > > +++ b/drivers/media/pci/intel/ivsc/mei_ace.c > > > @@ -0,0 +1,534 @@ > > > +// SPDX-License-Identifier: GPL-2.0-only > > > +/* > > > + * Copyright (C) 2023 Intel Corporation. All rights reserved. > > > + * Intel Visual Sensing Controller ACE Linux driver */ > > > + > > > +/* > > > + * To set ownership of camera sensor, there is specific command, > > > +which > > > + * is sent via MEI protocol. That's a two-step scheme where the > > > +firmware > > > + * first acks receipt of the command and later responses the command > > > +was > > > + * executed. The command sending function uses "completion" as the > > > + * synchronization mechanism. The notification for command is > > > +received > > > + * via a mei callback which wakes up the caller. There can be only > > > +one > > > + * outstanding command at a time. > > > > Could you document the dependencies in the sensor initialisation (ace + > > csi) > > This is about ownership instead of dependency, if host sensor driver configure > sensor with ownership on IVSC, probably it will be changed by firmware somehow. > > > and how the sensor is powered (i.e. no direct control of the PMIC from the > > host?)? > > The power line is directly connected to IVSC instead of host, when ownership > switched to host, sensor is already powered up by firmware. Good. Please also document this in the comment. -- Kind regards, Sakari Ailus
