Message-ID: <DM6PR11MB4316F0F7B7A0F52FA5DF03BE8DBD9@DM6PR11MB4316.namprd11.prod.outlook.com>
Date:   Fri, 17 Mar 2023 07:30:19 +0000
From:   "Wu, Wentong" <wentong.wu@...el.com>
To:     Hans de Goede <hdegoede@...hat.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>
CC:     "mchehab@...nel.org" <mchehab@...nel.org>,
        "linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
        "Pandruvada, Srinivas" <srinivas.pandruvada@...el.com>,
        "pierre-louis.bossart@...ux.intel.com" 
        <pierre-louis.bossart@...ux.intel.com>,
        "Wang, Zhifeng" <zhifeng.wang@...el.com>,
        "Ye, Xiang" <xiang.ye@...el.com>,
        "Qiu, Tian Shu" <tian.shu.qiu@...el.com>,
        "Cao, Bingbu" <bingbu.cao@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v2 0/3] media: pci: intel: ivsc: Add driver of Intel
 Visual Sensing Controller(IVSC)



> -----Original Message-----
> From: Hans de Goede <hdegoede@...hat.com>
> Sent: Thursday, March 16, 2023 5:04 PM
> 
> Hi,
> 
> On 3/16/23 03:58, Wu, Wentong wrote:
> >
> >
> >> -----Original Message-----
> >> From: Hans de Goede <hdegoede@...hat.com>
> >> Sent: Thursday, March 9, 2023 11:24 PM
> >>
> >> <re-added the previous Cc list, which I dropped because of the large
> >> attachments>
> >>
> >> Hi Wentong,
> >>
> >> On 3/9/23 15:29, Wu, Wentong wrote:
> >>> Hi Hans,
> >>>
> >>> Thanks
> >>>
> >>> And AFAICT, there is no IVSC device on your Dell Latitude 9420 where
> >>> the
> >> platform is based on TGL instead of ADL, and I have never heard IVSC
> >> runs on TGL,  if no IVSC, INT3472 will control sensor's power.
> >>> And I will double confirm with people who know dell product well tomorrow.
> >>
> >> Ah, I was under the impression that there was an IVSC there because:
> >>
> >> 1. The sensor driver for the used sensor (tries to) poke the IVSC 2.
> >> Things did not work without building the IVSC drivers, but that might
> >>    be due to a dependency on the LCJA GPIO expander instead
> >
> > Below is your dmesg log, the required SPI controller for IVSC isn't here.
> >
> > [   35.538114] ljca 2-6:1.0: acked sem wait timed out ret:0 timeout:20 ack:0
> > [   35.538129] ljca 2-6:1.0: MNG_ENUM_SPI failed ret:-110 len:7 num:0
> > [   35.538621] ljca 2-6:1.0: LJCA USB device init success
> > [   35.538776] usbcore: registered new interface driver ljca
> >
> > Also I checked your SSDT, there is no IVSC device and the sensor
> > device depends on
> > INT3472 instead of IVSC device as on my setup.
> 
> Ack.
> 
> >> But you might very well be right, that would also explain the "intel vsc not
> ready"
> >> messages in dmesg.
> >>
> >> If with the IVSC case the IVSC controls the power to the sensor too,
> >> then another option might be to model the I2C-switch + the
> >> power-control as a powerdown GPIO for the sensor, which most sensor
> drivers already try to use.
> >> The advantage of doing this would be that GPIO lookups can reference
> >> the GPIO provider + consumer by device-name so then we don't need to
> >> have both devices instantiated at the time of
> >> adding the GPIO lookup.   And in that case we could e.g. add the lookup
> >> before registering the I2C controller.
> >
> > Can we add IVSC device to acpi_honor_dep_ids, so that when everything
> > is done during mei_ace probe, acpi_dev_clear_dependencies can make sensor
> start probe?
> 
> Does the sensor ACPI device node have an ACPI _DEP on the IVSC device ?

Yes,

> 
> If yes, then yes we can add the IVSC device to acpi_honor_dep_id and make
> mei_ace probe call acpi_dev_clear_dependencies().

But I prefer the powerdown gpio model, because we have to follow the commands
sequences as below which is required by firmware, runtime pm is hard to achieve this.
+	/* switch camera sensor ownership to host */
+	ret = ace_set_camera_owner(ACE_CAMERA_HOST);
+	if (ret)
+		goto error;
+
+	/* switch CSI-2 link to host */
+	ret = csi_set_link_owner(CSI_LINK_HOST, callback, context);
+	if (ret)
+		goto release_camera;
+
+	/* configure CSI-2 link */
+	ret = csi_set_link_cfg(nr_of_lanes, link_freq);
+	if (ret)
+		goto release_csi;

BR,
Wentong
> 
> Regards,
> 
> Hans
> 
> 
> 
> >> Sakari, what do you think of instead of using runtime-pm + devlinks
> >> having the IVSC code export a powerdown GPIO to the sensor ?
> >>
> >> This also decouples the ivsc powerstate from the sensor power-state
> >> which might be useful if we ever want to use some of the more
> >> advanced ivsc features, where AFAICT the ivsc fully controls the sensor.
> >>
> >> Regards,
> >>
> >> Hans
> >>
> >>
> >>
> >>
> >>>> -----Original Message-----
> >>>> From: Hans de Goede <hdegoede@...hat.com>
> >>>> Sent: Thursday, March 9, 2023 9:30 PM
> >>>> To: Wu, Wentong <wentong.wu@...el.com>
> >>>> Subject: Re: [PATCH v2 0/3] media: pci: intel: ivsc: Add driver of
> >>>> Intel Visual Sensing Controller(IVSC)
> >>>>
> >>>> Hi Wentong,
> >>>>
> >>>> Attached are the requested dmesg + acpidump for the Dell Latitude 9420.
> >>>>
> >>>> Regards,
> >>>>
> >>>> Hans
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> On 3/9/23 14:21, Wu, Wentong wrote:
> >>>>> Hi
> >>>>>
> >>>>>> -----Original Message-----
> >>>>>> From: Hans de Goede <hdegoede@...hat.com>
> >>>>>> Sent: Thursday, March 9, 2023 5:28 PM
> >>>>>>
> >>>>>> Hi,
> >>>>>>
> >>>>>> On 3/9/23 02:08, Wu, Wentong wrote:
> >>>>>>>
> >>>>>>>
> >>>>>>>> -----Original Message-----
> >>>>>>>> From: Hans de Goede <hdegoede@...hat.com>
> >>>>>>>> Sent: Tuesday, March 7, 2023 5:10 PM
> >>>>>>>>
> >>>>>>>> Hi,
> >>>>>>>>
> >>>>>>>> On 3/7/23 09:40, Wu, Wentong wrote:
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>> -----Original Message-----
> >>>>>>>>>> From: Sakari Ailus <sakari.ailus@...ux.intel.com>
> >>>>>>>>>> Sent: Tuesday, March 7, 2023 4:30 PM
> >>>>>>>>>>
> >>>>>>>>>> Hi Wentong,
> >>>>>>>>>>
> >>>>>>>>>> On Tue, Mar 07, 2023 at 08:17:04AM +0000, Wu, Wentong wrote:
> >>>>>>>>>>>
> >>>>>>>>>>>
> >>>>>>>>>>>> -----Original Message-----
> >>>>>>>>>>>> From: Hans de Goede <hdegoede@...hat.com>
> >>>>>>>>>>>> Sent: Wednesday, March 1, 2023 6:42 PM
> >>>>>>>>>>>>
> >>>>>>>>>>>> Hi,
> >>>>>>>>>>>>
> >>>>>>>>>>>> On 3/1/23 11:34, Sakari Ailus wrote:
> >>>>>>>>>>>>> Hi Wentong,
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> On Mon, Feb 13, 2023 at 10:23:44AM +0800, Wentong Wu
> wrote:
> >>>>>>>>>>>>>> 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.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> I thought this for a while and did some research, and I
> >>>>>>>>>>>>> can suggest the
> >>>>>>>>>>>>> following:
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> - The IVSC sub-device implements a control for privacy
> >>>>>>>> (V4L2_CID_PRIVACY
> >>>>>>>>>>>>>   is a good fit).
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> - Camera sensor access needs to be requested from IVSC
> >>>>>>>>>>>>> before accessing
> >>>>>>>>>> the
> >>>>>>>>>>>>>   sensor via I²C. The IVSC ownership control needs to be
> >>>>>>>>>>>>> in the
> >> right
> >>>>>>>>>>>>>   setting for this to work, and device links can be used
> >>>>>>>>>>>>> for that
> >>>> purpose
> >>>>>>>>>>>>>   (see device_link_add()). With DL_FLAG_PM_RUNTIME and
> >>>>>>>>>>>> DL_FLAG_RPM_ACTIVE,
> >>>>>>>>>>>>>   the supplier devices will be PM runtime resumed before
> >>>>>>>>>>>>> the
> >>>> consumer
> >>>>>>>>>>>>>   (camera sensor). As these devices are purely virtual on
> >>>>>>>>>>>>> host side and
> >>>>>> has
> >>>>>>>>>>>>>   no power state as such, you can use runtime PM callbacks
> >>>>>>>>>>>>> to transfer
> >>>>>>>> the
> >>>>>>>>>>>>>   ownership.
> >>>>>>>>>>>>
> >>>>>>>>>>>> Interesting proposal to use device-links + runtime-pm for
> >>>>>>>>>>>> this instead of modelling this as an i2c-mux. FWIW I'm fine
> >>>>>>>>>>>> with going this route instead of using an i2c-mux approach.
> >>>>>>>>>>>>
> >>>>>>>>>>>> I have been thinking about the i2c-mux approach a bit and
> >>>>>>>>>>>> the problem is that we are not really muxing but want to
> >>>>>>>>>>>> turn on/off control and AFAIK the i2c-mux framework simply
> >>>>>>>>>>>> leaves the mux muxed to the last used i2c-chain, so control
> >>>>>>>>>>>> will never be released when the i2c
> >>>>>>>>>> transfers are done.
> >>>>>>>>>>>>
> >>>>>>>>>>>> And if were to somehow modify things (or maybe there
> >>>>>>>>>>>> already is some release
> >>>>>>>>>>>> callback) then the downside becomes that the i2c-mux core
> >>>>>>>>>>>> code operates at the i2c transfer level. So each i2c
> >>>>>>>>>>>> read/write would then enable +
> >>>>>>>>>> disavle control.
> >>>>>>>>>>>>
> >>>>>>>>>>>> Modelling this using something like runtime pm as such is a
> >>>>>>>>>>>> much better fit because then we request control once on
> >>>>>>>>>>>> probe / stream-on and release it once we are fully done,
> >>>>>>>>>>>> rather then requesting + releasing control once per i2c- transfer.
> >>>>>>>>>>>
> >>>>>>>>>>> Seems runtime pm can't fix the problem of initial i2c
> >>>>>>>>>>> transfer during sensor driver probe, probably we have to
> >>>>>>>>>>> switch to i2c-mux modeling
> >>>>>>>> way.
> >>>>>>>>>>
> >>>>>>>>>> What do you mean? The supplier devices are resumed before the
> >>>>>>>>>> driver's probe is called.
> >>>>>>>>>
> >>>>>>>>> But we setup the link with device_link_add during IVSC
> >>>>>>>>> driver's probe, we can't guarantee driver probe's sequence.
> >>>>>>>>
> >>>>>>>> Then maybe we need to do the device_link_add somewhere else.
> >>>>>>>
> >>>>>>> sensor's parent is the LJCA I2C device whose driver is being
> >>>>>>> upstream https://www.spinics.net/lists/kernel/msg4702552.htmland
> >>>>>>> and sensor's power is controlled by IVSC instead of INT3472 if
> >>>>>>> IVSC
> >> enabled.
> >>>>>>
> >>>>>> I believe that the INT3472 code is still involved at least on a
> >>>>>> Dell Latitude 9420 the INT3472 code still needs to set the
> >>>>>> clock-enable and the privacy-LED GPIOs otherwise the main camera
> >>>>>> won't
> >> work.
> >>>>>>
> >>>>>> So I'm not sure what you mean with "sensor's power is controlled
> >>>>>> by IVSC instead of INT3472" ?
> >>>>>
> >>>>> Could you please share your kernel log and DSDT? Thanks
> >>>>>
> >>>>> BR,
> >>>>> Wentong
> >>>>>>
> >>>>>>
> >>>>>>> struct device_link *device_link_add(struct device *consumer,
> >>>>>>>                                     struct device *supplier, u32
> >>>>>>> flags)
> >>>>>>>
> >>>>>>> So probably we have to add above device_link_add in LJCA I2C's
> >>>>>>> driver, and we can find the consumer(camera sensor) with ACPI
> >>>>>>> API, but the supplier, mei_ace, is mei client device under mei
> >>>>>>> framework and it's dynamically allocated device instead of ACPI
> >>>>>>> device, probably I can find its parent with some ACPI lookup
> >>>>>>> from this LJCA I2C device, but unfortunately mei framework
> >>>>>>> doesn't export the API to find mei client device with its parent
> >>>>>>> bus device(struct
> >> mei_device).
> >>>>>>>
> >>>>>>> I'm not sure if modeling this mei_ace as LJCA I2C's runtime
> >>>>>>> power control is acceptable, if yes, probably this mei_ace
> >>>>>>> driver have to go with LJCA I2C device driver.
> >>>>>>
> >>>>>> Looking at the ACPI table the sensor ACPI device has 2 _DEP-s
> >>>>>> listed the I2C controller and the INT3472 device. Since we are
> >>>>>> already doing similar setup in the INT3472 device that seems like
> >>>>>> a good place to add the device_link()-s (it can return
> >>>>>> -EPROBE_DEFER to wait for the mei_ace
> >>>> to show up).
> >>>>>>
> >>>>>> But when the INT3472 code runs, the consumer device does not
> >>>>>> exist yet and AFAICT the same is true when the LCJA
> >>>>>> i2c-controller driver is getting
> >>>> registered.
> >>>>>> The consumer only exists when the i2c_client is instantiated and
> >>>>>> at that point the sensor drivers probe() method can run
> >>>>>> immediately and we are too late to add the device_link.
> >>>>>>
> >>>>>> As a hobby project I have been working on atomisp2 support and I
> >>>>>> have a similar issue there. There is no INT3472 device there, but
> >>>>>> there is a _DSM method which needs to be used to figure out which
> >>>>>> ACPI GPIO resource is reset / powerdown and if the GPIOs are
> >>>>>> active-low
> >> or active high.
> >>>>>>
> >>>>>> I have written a little helper function to call the _DSM and to
> >>>>>> then turn this into lookups and call devm_acpi_dev_add_driver_gpios().
> >>>>>>
> >>>>>> Since on atomisp2 we cannot use the INT3472 driver to delay the
> >>>>>> sensor-driver probe and have the INT3472 driver setup the GPIO
> >>>>>> lookup, at least for the sensor drivers used with
> >>>>>> atomisp2 there is going to be a need to add a single line to probe() like
> this:
> >>>>>>
> >>>>>> 	v4l2_get_acpi_sensor_info(&i2c_client->dev, NULL);
> >>>>>>
> >>>>>> To me it sounds like we need to do something similar here and
> >>>>>> extend the helper function which I have written (but not yet
> >>>>>> submitted
> >> upstream) :
> >>>>>>
> >>>>>> https://github.com/jwrdegoede/linux-
> >>>>>> sunxi/commit/e2287979db43d46fa7d354c1bde92eb6219b613d
> >>>>>>
> >>>>>> To also setup the device-links needed for the runtime-pm solution
> >>>>>> to getting the i2c passed through to the sensor.
> >>>>>>
> >>>>>> Ideally v4l2_get_acpi_sensor_info() should return void (easier to
> >>>>>> use in the sensor drivers) but I think it should return an int,
> >>>>>> so that it can e.g. return - EPROBE_DEFER to wait for the mei_ace.
> >>>>>>
> >>>>>> Regards,
> >>>>>>
> >>>>>> Hans
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>>> The mainline kernel delays probing of camera sensors on Intel
> >>>>>>>> platforms until the INT3472 driver has probed the INT3472
> >>>>>>>> device on which the sensors have an ACPI _DEP.
> >>>>>>>>
> >>>>>>>> This is already used to make sure that clock lookups and
> >>>>>>>> regulator info is in place before the sensor's probe() function runs.
> >>>>>>>>
> >>>>>>>> So that when the driver does clk_get() it succeeds and so that
> >>>>>>>> regulator_get() does not end up returning a dummy regulator.
> >>>>>>>>
> >>>>>>>> So I think the code adding the device_link-s for the IVSC
> >>>>>>>> should be added
> >>>>>>>> to: drivers/platform/x86/intel/int3472/discrete.c and then the
> >>>>>>>> runtime-resume will happen before the sensor's probe() function runs.
> >>>>>>>>
> >>>>>>>> Likewise drivers/platform/x86/intel/int3472/discrete.c should
> >>>>>>>> also ensure that the ivsc driver's probe() has run before it
> >>>>>>>> calls
> >>>>>> acpi_dev_clear_dependencies().
> >>>>>>>>
> >>>>>>>> The acpi_dev_clear_dependencies() call in discrete.c tells the
> >>>>>>>> ACPI subsystem to go ahead and create the i2c-clients for the
> >>>>>>>> sensors and allow the sensor drivers to get loaded and probe the
> sensor.
> >>>>>>>>
> >>>>>>>> Regards,
> >>>>>>>>
> >>>>>>>> Hans
> >>>>>>>
> >>>>>
> >

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