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[v3,0/3] media: pci: intel: ivsc: Add driver of Intel Visual Sensing Controller(IVSC)

Message ID 1679898188-14426-1-git-send-email-wentong.wu@intel.com
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Series media: pci: intel: ivsc: Add driver of Intel Visual Sensing Controller(IVSC) | expand

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Wu, Wentong March 27, 2023, 6:23 a.m. UTC
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 exported via v4l2 sub-device.

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, users are informed via
v4l2 control API.

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.
 - ivsc_csi: MEI client driver to send commands and receive notifications
from CSI module.
 - ivsc_ace: MEI client driver to send commands and get status from ACE
module.
Interface is exposed via v4l2 sub-devcie APIs 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
  ACPI: delay enumeration of devices with a _DEP pointing to INTC1059
    device

 drivers/acpi/scan.c                       |   1 +
 drivers/media/pci/Kconfig                 |   1 +
 drivers/media/pci/intel/Makefile          |   2 +
 drivers/media/pci/intel/ivsc/Kconfig      |  12 +
 drivers/media/pci/intel/ivsc/Makefile     |  10 +
 drivers/media/pci/intel/ivsc/csi_bridge.c | 332 +++++++++++++
 drivers/media/pci/intel/ivsc/csi_bridge.h | 122 +++++
 drivers/media/pci/intel/ivsc/mei_ace.c    | 534 ++++++++++++++++++++
 drivers/media/pci/intel/ivsc/mei_csi.c    | 775 ++++++++++++++++++++++++++++++
 9 files changed, 1789 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/csi_bridge.c
 create mode 100644 drivers/media/pci/intel/ivsc/csi_bridge.h
 create mode 100644 drivers/media/pci/intel/ivsc/mei_ace.c
 create mode 100644 drivers/media/pci/intel/ivsc/mei_csi.c

Comments

Sakari Ailus March 28, 2023, 7:48 p.m. UTC | #1
On Tue, Mar 28, 2023 at 07:32:27AM +0000, Wu, Wentong wrote:
> 
> 
> > -----Original Message-----
> > From: Sakari Ailus <sakari.ailus@linux.intel.com>
> > Sent: Monday, March 27, 2023 5:37 PM
> > 
> > Hi Wentong,
> > 
> > On Mon, Mar 27, 2023 at 08:13:29AM +0000, Wu, Wentong wrote:
> > >
> > >
> > > > -----Original Message-----
> > > > From: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > > Sent: Monday, March 27, 2023 3:50 PM
> > > >
> > > > Hi Wentong,
> > > >
> > > > On Mon, Mar 27, 2023 at 07:33:48AM +0000, Wu, Wentong wrote:
> > > > >
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > > > > Sent: Monday, March 27, 2023 3:21 PM
> > > > > >
> > > > > > Hi Wentong,
> > > > > >
> > > > > > On Mon, Mar 27, 2023 at 02:23:05PM +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 exported
> > > > via v4l2 sub-device.
> > > > > > >
> > > > > > > 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, users are informed via
> > > > > > > v4l2 control API.
> > > > > > >
> > > > > > > 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.
> > > > > > >  - ivsc_csi: MEI client driver to send commands and receive
> > > > > > > notifications from CSI module.
> > > > > > >  - ivsc_ace: MEI client driver to send commands and get status
> > > > > > > from ACE module.
> > > > > > > Interface is exposed via v4l2 sub-devcie APIs to acquire and
> > > > > > > release camera sensor and CSI-2 link.
> > > > > >
> > > > > > Thanks for the update.
> > > > > >
> > > > > > Could you elaborate the decision of keeping the csi_bridge
> > > > > > entirely separate from the cio2_bridge (to be turned to ipu_bridge first)?
> > > > > > Both are doing essentially the same and using the same data
> > > > > > structures,
> > > > aren't they?
> > > > >
> > > > > yes, they're doing same thing to bridge the software nodes needed
> > > > > by v4l2, but they have different type devices(pci and mei_client
> > > > > device) and dependency. And they have same SSDB definition in
> > > > > DSDT, so the structures are almost same.
> > > >
> > > > If there are differences, what are they?
> > > >
> > > The properties of swnode are same, because we need same info to
> > > configure CSI2. But csi bridge can get sensor connected to IVSC by
> > > dependency info instead of just polling the only supported sensors for
> > > ipu. Also IVSC
> > 
> > It's totally fine the method for finding the sensor is different, this should be an
> > extra argument for the bridge init function and a small number of lines of
> > additional code.
> > 
> > > doesn't need vcm. And the topology of dependency is different.
> > 
> > The VCM is optional for current cio2_bridge, too.
> > 
> > It also seems that this currently creates swnodes on mei csi side only for the
> > connection towards the sensor, not the IPU.
> 
> IPU could find the MEI CSI software node by software_node_find_by_name,
> and then setup the bridge between MEI CSI and IPU.
> 
> > At the moment you can't reliably
> > add software nodes to a device that has may be already probing so both of
> > these should be created at the same time.
> 
> If you're worried about sequence, IPU driver could make software node and
> register it, MEI CSI bridge could find IPU software node by software_node_find_by_name,
> if the return value is NULL, driver will defer the probe.

The IPU driver would also need to figure out whether a given sensor should
be behind the IVSC. I imagine it'll be hard to achieve this reasonably
neatly if you split the implementation into different parts --- both of
which need the same information from the same place (and in neither case
it's under the same device than to which the driver is bound).

> 
> > 
> > >
> > > > What comes to cio2_bridge, the fact that it's related to a PCI
> > > > device doesn't seem to matter after initialisation so it could as well work
> > with struct device.
> > > >
> > > > >
> > > > > I have no idea what the ipu bridge would be like, but IVSC csi
> > > > > bridge can be configured via kconfig to enable/disable.
> > > >
> > > > Please work out the details with Bingbu.
> > >
> > > @bingbu.cao@linux.intel.com @Sakari Ailus Please share your design idea
> > here.
> > > What the ipu bridge would be like?  What's the responsibility of ipu bridge?
> > 
> > I'd expect Bingbu to have patches to turn the current cio2_bridge to an
> > ipu_bridge at some point. These should come on top of those patches.
> 
> When will this be ready if you already make the plan? But could you please help
> review my other patches except bridge?

Please configure your e-mail client to wrap your lines at most at 74
characters or so.

I think it's binding this all together that is the concern, the individual
drivers much less so.
Sakari Ailus March 29, 2023, 8:48 a.m. UTC | #2
Hi Wentong,

On Mon, Mar 27, 2023 at 02:23:06PM +0800, Wentong Wu wrote:
> CSI is a submodule of IVSC which can route camera sensor data
> to the outbound MIPI CSI-2 interface.
> 
> The interface communicating with firmware is via MEI. There is
> a separate MEI UUID, which this driver uses to enumerate.
> 
> To route camera sensor data to host, the information of link
> frequency and number of data lanes is sent to firmware by
> sending MEI command when starting stream.
> 
> CSI also provides a privacy mode. When privacy mode is turned
> on, camera sensor can't be used. This means that both IVSC and
> host Image Processing Unit(IPU) can't get image data. And when
> this mode is turned on, host Image Processing Unit(IPU) driver
> is informed via v4l2 control callback, so that user can be
> notified.
> 
> Signed-off-by: Wentong Wu <wentong.wu@intel.com>
> ---
>  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/csi_bridge.c | 332 +++++++++++++
>  drivers/media/pci/intel/ivsc/csi_bridge.h | 122 +++++
>  drivers/media/pci/intel/ivsc/mei_csi.c    | 775 ++++++++++++++++++++++++++++++
>  7 files changed, 1251 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/csi_bridge.c
>  create mode 100644 drivers/media/pci/intel/ivsc/csi_bridge.h
>  create mode 100644 drivers/media/pci/intel/ivsc/mei_csi.c

I'm commenting just mei_csi this time...

> diff --git a/drivers/media/pci/intel/ivsc/mei_csi.c b/drivers/media/pci/intel/ivsc/mei_csi.c
> new file mode 100644
> index 0000000..6a01537
> --- /dev/null
> +++ b/drivers/media/pci/intel/ivsc/mei_csi.c
> @@ -0,0 +1,775 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2023 Intel Corporation. All rights reserved.
> + * Intel Visual Sensing Controller CSI Linux driver
> + */
> +
> +/*
> + * To set ownership of CSI-2 link and to configure CSI-2 link, there
> + * are specific commands, which are sent via MEI protocol. The send
> + * command function uses "completion" as a synchronization mechanism.
> + * The response for command is received via a mei callback which wakes
> + * up the caller. There can be only one outstanding command at a time.
> + */
> +
> +#include <linux/completion.h>
> +#include <linux/delay.h>
> +#include <linux/kernel.h>
> +#include <linux/math64.h>
> +#include <linux/mei_cl_bus.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/slab.h>
> +#include <linux/units.h>
> +#include <linux/uuid.h>
> +#include <linux/workqueue.h>
> +
> +#include <media/v4l2-async.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-fwnode.h>
> +#include <media/v4l2-subdev.h>
> +
> +#define MEI_CSI_DRIVER_NAME "ivsc_csi"
> +
> +/* the 5s used here is based on experiment */
> +#define CSI_CMD_TIMEOUT (5 * HZ)
> +/* to setup CSI-2 link an extra delay needed and determined experimentally */
> +#define CSI_FW_READY_DELAY_MS 100
> +/* link frequency unit is 100kHz */
> +#define CSI_LINK_FREQ(x) ((u32)(div_u64(x, 100 * HZ_PER_KHZ)))
> +
> +/*
> + * identify the command id supported by firmware
> + * IPC, as well as the privacy notification id
> + * used when processing privacy event.
> + */
> +enum csi_cmd_id {
> +	/* used to set csi ownership */
> +	CSI_SET_OWNER = 0,
> +
> +	/* used to configure CSI-2 link */
> +	CSI_SET_CONF = 2,
> +
> +	/* privacy notification id used when privacy state changes */
> +	CSI_PRIVACY_NOTIF = 6,
> +};
> +
> +/* CSI-2 link ownership definition */
> +enum csi_link_owner {
> +	CSI_LINK_IVSC,
> +	CSI_LINK_HOST,
> +};
> +
> +/* privacy status definition */
> +enum ivsc_privacy_status {
> +	CSI_PRIVACY_OFF,
> +	CSI_PRIVACY_ON,
> +	CSI_PRIVACY_MAX,
> +};
> +
> +enum csi_pads {
> +	CSI_PAD_SOURCE,
> +	CSI_PAD_SINK,
> +	CSI_NUM_PADS
> +};
> +
> +/* configuration of the CSI-2 link between host and IVSC */
> +struct csi_link_cfg {
> +	/* number of data lanes used on the CSI-2 link */
> +	u32 nr_of_lanes;
> +
> +	/* frequency of the CSI-2 link */
> +	u32 link_freq;
> +
> +	/* for future use */
> +	u32 rsvd[2];
> +} __packed;
> +
> +/* CSI command structure */
> +struct csi_cmd {
> +	u32 cmd_id;
> +	union _cmd_param {
> +		u32 param;
> +		struct csi_link_cfg conf;
> +	} param;
> +} __packed;
> +
> +/* CSI notification structure */
> +struct csi_notif {
> +	u32 cmd_id;
> +	int status;
> +	union _resp_cont {
> +		u32 cont;
> +		struct csi_link_cfg conf;
> +	} cont;
> +} __packed;
> +
> +struct mei_csi {
> +	struct mei_cl_device *cldev;
> +
> +	/* command response */
> +	struct csi_notif cmd_response;
> +	/* used to wait for command response from firmware */
> +	struct completion cmd_completion;
> +	/* protect command download */
> +	struct mutex lock;
> +
> +	struct v4l2_subdev subdev;
> +	struct v4l2_subdev *remote;
> +	struct v4l2_async_notifier notifier;
> +	struct v4l2_ctrl_handler ctrl_handler;
> +	struct v4l2_ctrl *privacy_ctrl;
> +	unsigned int remote_pad;
> +	/* start streaming or not */
> +	int streaming;
> +
> +	struct media_pad pads[CSI_NUM_PADS];
> +	struct v4l2_mbus_framefmt format_mbus[CSI_NUM_PADS];
> +
> +	/* number of data lanes used on the CSI-2 link */
> +	u32 nr_of_lanes;
> +	/* frequency of the CSI-2 link */
> +	u64 link_freq;
> +
> +	/* privacy status */
> +	enum ivsc_privacy_status status;
> +};
> +
> +static const struct v4l2_mbus_framefmt mei_csi_format_mbus_default = {
> +	.width = 1,
> +	.height = 1,
> +	.code = MEDIA_BUS_FMT_Y8_1X8,
> +	.field = V4L2_FIELD_NONE,
> +};
> +
> +int csi_bridge_init(struct mei_cl_device *csi_dev);
> +
> +static inline struct mei_csi *notifier_to_csi(struct v4l2_async_notifier *n)
> +{
> +	return container_of(n, struct mei_csi, notifier);
> +}
> +
> +static inline struct mei_csi *sd_to_csi(struct v4l2_subdev *sd)
> +{
> +	return container_of(sd, struct mei_csi, subdev);
> +}
> +
> +/* send a command to firmware and mutex must be held by caller */
> +static int mei_csi_send(struct mei_csi *csi, u8 *buf, size_t len)
> +{
> +	struct csi_cmd *cmd = (struct csi_cmd *)buf;
> +	int ret;
> +
> +	reinit_completion(&csi->cmd_completion);
> +
> +	ret = mei_cldev_send(csi->cldev, buf, len);
> +	if (ret < 0)
> +		goto out;
> +
> +	ret = wait_for_completion_killable_timeout(&csi->cmd_completion,
> +						   CSI_CMD_TIMEOUT);
> +	if (ret < 0) {
> +		goto out;
> +	} else if (!ret) {
> +		ret = -ETIMEDOUT;
> +		goto out;
> +	}
> +
> +	/* command response status */
> +	ret = csi->cmd_response.status;
> +	if (ret) {
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	if (csi->cmd_response.cmd_id != cmd->cmd_id)
> +		ret = -EINVAL;
> +
> +out:
> +	return ret;
> +}
> +
> +/* set CSI-2 link ownership */
> +static int csi_set_link_owner(struct mei_csi *csi, enum csi_link_owner owner)
> +{
> +	struct csi_cmd cmd = { 0 };
> +	size_t cmd_size;
> +	int ret;
> +
> +	cmd.cmd_id = CSI_SET_OWNER;
> +	cmd.param.param = owner;
> +	cmd_size = sizeof(cmd.cmd_id) + sizeof(cmd.param.param);

In some cases you're using memset and in others not. If you don't need
memset, I'd prefer assigning the fields in variable declaration instead.

> +
> +	mutex_lock(&csi->lock);
> +
> +	ret = mei_csi_send(csi, (u8 *)&cmd, cmd_size);
> +
> +	mutex_unlock(&csi->lock);
> +
> +	return ret;
> +}
> +
> +/* configure CSI-2 link between host and IVSC */
> +static int csi_set_link_cfg(struct mei_csi *csi)
> +{
> +	struct csi_cmd cmd = { 0 };
> +	size_t cmd_size;
> +	int ret;
> +
> +	cmd.cmd_id = CSI_SET_CONF;
> +	cmd.param.conf.nr_of_lanes = csi->nr_of_lanes;
> +	cmd.param.conf.link_freq = CSI_LINK_FREQ(csi->link_freq);
> +	cmd_size = sizeof(cmd.cmd_id) + sizeof(cmd.param.conf);

Ditto.

> +
> +	mutex_lock(&csi->lock);
> +
> +	ret = mei_csi_send(csi, (u8 *)&cmd, cmd_size);
> +	/*
> +	 * wait configuration ready if download success. placing
> +	 * delay under mutex is to make sure current command flow
> +	 * completed before starting a possible new one.
> +	 */
> +	if (!ret)
> +		msleep(CSI_FW_READY_DELAY_MS);
> +
> +	mutex_unlock(&csi->lock);
> +
> +	return ret;
> +}
> +
> +/* callback for receive */
> +static void mei_csi_rx(struct mei_cl_device *cldev)
> +{
> +	struct mei_csi *csi = mei_cldev_get_drvdata(cldev);
> +	struct csi_notif notif = { 0 };
> +	int ret;
> +
> +	ret = mei_cldev_recv(cldev, (u8 *)&notif, sizeof(notif));
> +	if (ret < 0) {
> +		dev_err(&cldev->dev, "recv error: %d\n", ret);
> +		return;
> +	}
> +
> +	switch (notif.cmd_id) {
> +	case CSI_PRIVACY_NOTIF:
> +		if (notif.cont.cont < CSI_PRIVACY_MAX) {
> +			csi->status = notif.cont.cont;
> +			v4l2_ctrl_s_ctrl(csi->privacy_ctrl, csi->status);
> +		}
> +		break;
> +	case CSI_SET_OWNER:
> +	case CSI_SET_CONF:
> +		memcpy(&csi->cmd_response, &notif, ret);
> +
> +		complete(&csi->cmd_completion);
> +		break;
> +	default:
> +		break;
> +	}
> +}
> +
> +static int mei_csi_pre_streamon(struct v4l2_subdev *sd, u32 flags)
> +{
> +	struct v4l2_querymenu qm = { .id = V4L2_CID_LINK_FREQ, };
> +	struct v4l2_mbus_config mbus_config = { 0 };
> +	struct mei_csi *csi = sd_to_csi(sd);
> +	struct v4l2_ctrl *ctrl;
> +	int ret = 0;
> +
> +	if (!csi->remote)
> +		return -ENODEV;
> +
> +	ret = v4l2_subdev_call(csi->remote, pad, get_mbus_config,
> +			       csi->remote_pad, &mbus_config);
> +	if (ret)
> +		return ret;

You're already parsing the endpoint in probe(). Do you need this, assuming
the sensor has a static lane configuration? Virtually all do.

Could this all be done via the s_stream() op instead?

> +
> +	if (mbus_config.type != V4L2_MBUS_CSI2_DPHY)
> +		return -EINVAL;
> +
> +	csi->nr_of_lanes = mbus_config.bus.mipi_csi2.num_data_lanes;
> +
> +	ctrl = v4l2_ctrl_find(csi->remote->ctrl_handler, V4L2_CID_LINK_FREQ);
> +	if (!ctrl)
> +		return -EINVAL;
> +	qm.index = v4l2_ctrl_g_ctrl(ctrl);
> +
> +	ret = v4l2_querymenu(csi->remote->ctrl_handler, &qm);
> +	if (ret)
> +		return ret;
> +
> +	csi->link_freq = qm.value;
> +
> +	return ret;
> +}
> +
> +static int mei_csi_set_stream(struct v4l2_subdev *sd, int enable)
> +{
> +	struct mei_csi *csi = sd_to_csi(sd);
> +	int ret = 0;
> +
> +	if (enable && csi->streaming == 0) {
> +		/* switch CSI-2 link to host */
> +		ret = csi_set_link_owner(csi, CSI_LINK_HOST);
> +		if (ret < 0)
> +			goto err;
> +
> +		/* configure CSI-2 link */
> +		ret = csi_set_link_cfg(csi);
> +		if (ret < 0)
> +			goto err;
> +
> +		ret = v4l2_subdev_call(csi->remote, video, s_stream, 1);
> +		if (ret)
> +			goto err;
> +	} else if (!enable && csi->streaming == 1) {
> +		v4l2_subdev_call(csi->remote, video, s_stream, 0);
> +
> +		/* switch CSI-2 link to IVSC */
> +		ret = csi_set_link_owner(csi, CSI_LINK_IVSC);
> +		if (ret < 0)
> +			goto err;

I'd complain (e.g. dev_warn()) but return zero in this case. There's not
much if anything the caller can do with this.

> +	}
> +
> +	csi->streaming = enable;
> +
> +err:
> +	return ret;
> +}
> +
> +static struct v4l2_mbus_framefmt *
> +mei_csi_get_pad_format(struct v4l2_subdev *sd,
> +		       struct v4l2_subdev_state *sd_state,
> +		       unsigned int pad, u32 which)
> +{
> +	struct mei_csi *csi = sd_to_csi(sd);
> +
> +	switch (which) {
> +	case V4L2_SUBDEV_FORMAT_TRY:
> +		return v4l2_subdev_get_try_format(sd, sd_state, pad);
> +	case V4L2_SUBDEV_FORMAT_ACTIVE:
> +		return &csi->format_mbus[pad];
> +	default:
> +		return NULL;
> +	}
> +}
> +
> +static int mei_csi_init_cfg(struct v4l2_subdev *sd,
> +			    struct v4l2_subdev_state *sd_state)
> +{
> +	struct v4l2_mbus_framefmt *mbusformat;
> +	struct mei_csi *csi = sd_to_csi(sd);
> +	unsigned int i;
> +
> +	mutex_lock(&csi->lock);
> +
> +	for (i = 0; i < sd->entity.num_pads; i++) {
> +		mbusformat = v4l2_subdev_get_try_format(sd, sd_state, i);
> +		*mbusformat = mei_csi_format_mbus_default;
> +	}
> +
> +	mutex_unlock(&csi->lock);
> +
> +	return 0;
> +}
> +
> +static int mei_csi_get_fmt(struct v4l2_subdev *sd,
> +			   struct v4l2_subdev_state *sd_state,
> +			   struct v4l2_subdev_format *format)
> +{
> +	struct v4l2_mbus_framefmt *mbusformat;
> +	struct mei_csi *csi = sd_to_csi(sd);
> +
> +	mutex_lock(&csi->lock);
> +
> +	mbusformat = mei_csi_get_pad_format(sd, sd_state, format->pad,
> +					    format->which);
> +	if (mbusformat)
> +		format->format = *mbusformat;
> +
> +	mutex_unlock(&csi->lock);
> +
> +	return 0;
> +}

It'd be nice to have also enum_mbus_code support. Video mux of course
didn't have this either. Something that could be done in the framework,
including validating the mbus format.

> +
> +static int mei_csi_set_fmt(struct v4l2_subdev *sd,
> +			   struct v4l2_subdev_state *sd_state,
> +			   struct v4l2_subdev_format *format)
> +{
> +	struct v4l2_mbus_framefmt *source_mbusformat;
> +	struct v4l2_mbus_framefmt *mbusformat;
> +	struct mei_csi *csi = sd_to_csi(sd);
> +	struct media_pad *pad;
> +
> +	mbusformat = mei_csi_get_pad_format(sd, sd_state, format->pad,
> +					    format->which);
> +	if (!mbusformat)
> +		return -EINVAL;
> +
> +	source_mbusformat = mei_csi_get_pad_format(sd, sd_state,
> +						   CSI_PAD_SOURCE,
> +						   format->which);
> +	if (!source_mbusformat)
> +		return -EINVAL;
> +
> +	v4l_bound_align_image(&format->format.width, 1, 65536, 0,
> +			      &format->format.height, 1, 65536, 0, 0);
> +
> +	switch (format->format.code) {
> +	case MEDIA_BUS_FMT_RGB444_1X12:
> +	case MEDIA_BUS_FMT_RGB444_2X8_PADHI_BE:
> +	case MEDIA_BUS_FMT_RGB444_2X8_PADHI_LE:
> +	case MEDIA_BUS_FMT_RGB555_2X8_PADHI_BE:
> +	case MEDIA_BUS_FMT_RGB555_2X8_PADHI_LE:
> +	case MEDIA_BUS_FMT_RGB565_1X16:
> +	case MEDIA_BUS_FMT_BGR565_2X8_BE:
> +	case MEDIA_BUS_FMT_BGR565_2X8_LE:
> +	case MEDIA_BUS_FMT_RGB565_2X8_BE:
> +	case MEDIA_BUS_FMT_RGB565_2X8_LE:
> +	case MEDIA_BUS_FMT_RGB666_1X18:
> +	case MEDIA_BUS_FMT_RBG888_1X24:
> +	case MEDIA_BUS_FMT_RGB666_1X24_CPADHI:
> +	case MEDIA_BUS_FMT_BGR888_1X24:
> +	case MEDIA_BUS_FMT_GBR888_1X24:
> +	case MEDIA_BUS_FMT_RGB888_1X24:
> +	case MEDIA_BUS_FMT_RGB888_2X12_BE:
> +	case MEDIA_BUS_FMT_RGB888_2X12_LE:
> +	case MEDIA_BUS_FMT_ARGB8888_1X32:
> +	case MEDIA_BUS_FMT_RGB888_1X32_PADHI:
> +	case MEDIA_BUS_FMT_RGB101010_1X30:
> +	case MEDIA_BUS_FMT_RGB121212_1X36:
> +	case MEDIA_BUS_FMT_RGB161616_1X48:
> +	case MEDIA_BUS_FMT_Y8_1X8:
> +	case MEDIA_BUS_FMT_UV8_1X8:
> +	case MEDIA_BUS_FMT_UYVY8_1_5X8:
> +	case MEDIA_BUS_FMT_VYUY8_1_5X8:
> +	case MEDIA_BUS_FMT_YUYV8_1_5X8:
> +	case MEDIA_BUS_FMT_YVYU8_1_5X8:
> +	case MEDIA_BUS_FMT_UYVY8_2X8:
> +	case MEDIA_BUS_FMT_VYUY8_2X8:
> +	case MEDIA_BUS_FMT_YUYV8_2X8:
> +	case MEDIA_BUS_FMT_YVYU8_2X8:
> +	case MEDIA_BUS_FMT_Y10_1X10:
> +	case MEDIA_BUS_FMT_UYVY10_2X10:
> +	case MEDIA_BUS_FMT_VYUY10_2X10:
> +	case MEDIA_BUS_FMT_YUYV10_2X10:
> +	case MEDIA_BUS_FMT_YVYU10_2X10:
> +	case MEDIA_BUS_FMT_Y12_1X12:
> +	case MEDIA_BUS_FMT_UYVY12_2X12:
> +	case MEDIA_BUS_FMT_VYUY12_2X12:
> +	case MEDIA_BUS_FMT_YUYV12_2X12:
> +	case MEDIA_BUS_FMT_YVYU12_2X12:
> +	case MEDIA_BUS_FMT_UYVY8_1X16:
> +	case MEDIA_BUS_FMT_VYUY8_1X16:
> +	case MEDIA_BUS_FMT_YUYV8_1X16:
> +	case MEDIA_BUS_FMT_YVYU8_1X16:
> +	case MEDIA_BUS_FMT_YDYUYDYV8_1X16:
> +	case MEDIA_BUS_FMT_UYVY10_1X20:
> +	case MEDIA_BUS_FMT_VYUY10_1X20:
> +	case MEDIA_BUS_FMT_YUYV10_1X20:
> +	case MEDIA_BUS_FMT_YVYU10_1X20:
> +	case MEDIA_BUS_FMT_VUY8_1X24:
> +	case MEDIA_BUS_FMT_YUV8_1X24:
> +	case MEDIA_BUS_FMT_UYYVYY8_0_5X24:
> +	case MEDIA_BUS_FMT_UYVY12_1X24:
> +	case MEDIA_BUS_FMT_VYUY12_1X24:
> +	case MEDIA_BUS_FMT_YUYV12_1X24:
> +	case MEDIA_BUS_FMT_YVYU12_1X24:
> +	case MEDIA_BUS_FMT_YUV10_1X30:
> +	case MEDIA_BUS_FMT_UYYVYY10_0_5X30:
> +	case MEDIA_BUS_FMT_AYUV8_1X32:
> +	case MEDIA_BUS_FMT_UYYVYY12_0_5X36:
> +	case MEDIA_BUS_FMT_YUV12_1X36:
> +	case MEDIA_BUS_FMT_YUV16_1X48:
> +	case MEDIA_BUS_FMT_UYYVYY16_0_5X48:
> +	case MEDIA_BUS_FMT_JPEG_1X8:
> +	case MEDIA_BUS_FMT_AHSV8888_1X32:
> +	case MEDIA_BUS_FMT_SBGGR8_1X8:
> +	case MEDIA_BUS_FMT_SGBRG8_1X8:
> +	case MEDIA_BUS_FMT_SGRBG8_1X8:
> +	case MEDIA_BUS_FMT_SRGGB8_1X8:
> +	case MEDIA_BUS_FMT_SBGGR10_1X10:
> +	case MEDIA_BUS_FMT_SGBRG10_1X10:
> +	case MEDIA_BUS_FMT_SGRBG10_1X10:
> +	case MEDIA_BUS_FMT_SRGGB10_1X10:
> +	case MEDIA_BUS_FMT_SBGGR12_1X12:
> +	case MEDIA_BUS_FMT_SGBRG12_1X12:
> +	case MEDIA_BUS_FMT_SGRBG12_1X12:
> +	case MEDIA_BUS_FMT_SRGGB12_1X12:
> +	case MEDIA_BUS_FMT_SBGGR14_1X14:
> +	case MEDIA_BUS_FMT_SGBRG14_1X14:
> +	case MEDIA_BUS_FMT_SGRBG14_1X14:
> +	case MEDIA_BUS_FMT_SRGGB14_1X14:
> +	case MEDIA_BUS_FMT_SBGGR16_1X16:
> +	case MEDIA_BUS_FMT_SGBRG16_1X16:
> +	case MEDIA_BUS_FMT_SGRBG16_1X16:
> +	case MEDIA_BUS_FMT_SRGGB16_1X16:
> +		break;
> +	default:
> +		format->format.code = MEDIA_BUS_FMT_Y8_1X8;
> +		break;
> +	}
> +	if (format->format.field == V4L2_FIELD_ANY)
> +		format->format.field = V4L2_FIELD_NONE;
> +
> +	mutex_lock(&csi->lock);
> +
> +	pad = &csi->pads[format->pad];
> +	if (pad->flags & MEDIA_PAD_FL_SOURCE)
> +		format->format = csi->format_mbus[CSI_PAD_SINK];
> +
> +	*mbusformat = format->format;
> +
> +	if (pad->flags & MEDIA_PAD_FL_SINK)
> +		*source_mbusformat = format->format;
> +
> +	mutex_unlock(&csi->lock);
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_video_ops mei_csi_video_ops = {
> +	.s_stream = mei_csi_set_stream,
> +	.pre_streamon = mei_csi_pre_streamon,
> +};
> +
> +static const struct v4l2_subdev_pad_ops mei_csi_pad_ops = {
> +	.init_cfg = mei_csi_init_cfg,
> +	.get_fmt = mei_csi_get_fmt,
> +	.set_fmt = mei_csi_set_fmt,
> +};
> +
> +static const struct v4l2_subdev_ops mei_csi_subdev_ops = {
> +	.video = &mei_csi_video_ops,
> +	.pad = &mei_csi_pad_ops,
> +};
> +
> +static const struct media_entity_operations mei_csi_entity_ops = {
> +	.link_validate = v4l2_subdev_link_validate,
> +};
> +
> +static int mei_csi_notify_bound(struct v4l2_async_notifier *notifier,
> +				struct v4l2_subdev *subdev,
> +				struct v4l2_async_subdev *asd)
> +{
> +	struct mei_csi *csi = notifier_to_csi(notifier);
> +	int pad;
> +
> +	pad = media_entity_get_fwnode_pad(&subdev->entity, asd->match.fwnode,
> +					  MEDIA_PAD_FL_SOURCE);
> +	if (pad < 0)
> +		return pad;
> +
> +	csi->remote = subdev;
> +	csi->remote_pad = pad;
> +
> +	return media_create_pad_link(&subdev->entity, pad,
> +				     &csi->subdev.entity, 0,
> +				     MEDIA_LNK_FL_ENABLED |
> +				     MEDIA_LNK_FL_IMMUTABLE);
> +}
> +
> +static void mei_csi_notify_unbind(struct v4l2_async_notifier *notifier,
> +				  struct v4l2_subdev *subdev,
> +				  struct v4l2_async_subdev *asd)
> +{
> +	struct mei_csi *csi = notifier_to_csi(notifier);
> +
> +	csi->remote = NULL;
> +}
> +
> +static const struct v4l2_async_notifier_operations mei_csi_notify_ops = {
> +	.bound = mei_csi_notify_bound,
> +	.unbind = mei_csi_notify_unbind,
> +};
> +
> +static int mei_csi_init_control(struct mei_csi *csi)
> +{
> +	v4l2_ctrl_handler_init(&csi->ctrl_handler, 1);
> +	csi->ctrl_handler.lock = &csi->lock;
> +
> +	csi->privacy_ctrl = v4l2_ctrl_new_std(&csi->ctrl_handler, NULL,
> +					      V4L2_CID_PRIVACY, 0, 1, 1, 0);
> +	if (csi->ctrl_handler.error)
> +		return csi->ctrl_handler.error;

The control should be made volatile here (flags |=
V4L2_CTRL_FLAG_READ_ONLY) as it can't be changed by the user.

> +
> +	csi->subdev.ctrl_handler = &csi->ctrl_handler;
> +
> +	return 0;
> +}
> +
> +static int mei_csi_parse_firmware(struct mei_csi *csi)
> +{
> +	struct v4l2_fwnode_endpoint v4l2_ep = {
> +		.bus_type = V4L2_MBUS_CSI2_DPHY,
> +	};
> +	struct device *dev = &csi->cldev->dev;
> +	struct v4l2_async_subdev *asd;
> +	struct fwnode_handle *fwnode;
> +	struct fwnode_handle *ep;
> +	int ret;
> +
> +	ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev), 0, 0, 0);
> +	if (!ep) {
> +		dev_err(dev, "not connected to subdevice\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = v4l2_fwnode_endpoint_parse(ep, &v4l2_ep);
> +	if (ret) {
> +		dev_err(dev, "could not parse v4l2 endpoint\n");
> +		fwnode_handle_put(ep);
> +		return -EINVAL;
> +	}
> +
> +	fwnode = fwnode_graph_get_remote_endpoint(ep);
> +	fwnode_handle_put(ep);
> +
> +	v4l2_async_nf_init(&csi->notifier);
> +	csi->notifier.ops = &mei_csi_notify_ops;
> +
> +	asd = v4l2_async_nf_add_fwnode(&csi->notifier, fwnode,
> +				       struct v4l2_async_subdev);
> +	fwnode_handle_put(fwnode);
> +	if (IS_ERR(asd))
> +		return PTR_ERR(asd);
> +
> +	ret = v4l2_async_subdev_nf_register(&csi->subdev, &csi->notifier);
> +	if (ret)
> +		v4l2_async_nf_cleanup(&csi->notifier);
> +
> +	return ret;
> +}
> +
> +static int mei_csi_probe(struct mei_cl_device *cldev,
> +			 const struct mei_cl_device_id *id)
> +{
> +	struct mei_csi *csi;
> +	int ret;
> +
> +	/*
> +	 * no connections to sensor are defined in firmware, try to
> +	 * build connections as software_nodes parsed from SSDB.
> +	 */
> +	ret = csi_bridge_init(cldev);
> +	if (ret)
> +		return ret;
> +
> +	csi = devm_kzalloc(&cldev->dev, sizeof(struct mei_csi), GFP_KERNEL);
> +	if (!csi)
> +		return -ENOMEM;
> +
> +	csi->cldev = cldev;
> +	mutex_init(&csi->lock);
> +	init_completion(&csi->cmd_completion);
> +
> +	mei_cldev_set_drvdata(cldev, csi);
> +
> +	ret = mei_cldev_enable(cldev);
> +	if (ret < 0) {
> +		dev_err(&cldev->dev, "mei_cldev_enable failed: %d\n", ret);
> +		goto destroy_mutex;
> +	}
> +
> +	ret = mei_cldev_register_rx_cb(cldev, mei_csi_rx);
> +	if (ret) {
> +		dev_err(&cldev->dev, "event cb registration failed: %d\n", ret);
> +		goto err_disable;
> +	}
> +
> +	ret = mei_csi_parse_firmware(csi);
> +	if (ret)
> +		goto err_disable;
> +
> +	csi->subdev.dev = &cldev->dev;
> +	v4l2_subdev_init(&csi->subdev, &mei_csi_subdev_ops);
> +	v4l2_set_subdevdata(&csi->subdev, csi);
> +	csi->subdev.flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	csi->subdev.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
> +	csi->subdev.entity.ops = &mei_csi_entity_ops;
> +
> +	ret = mei_csi_init_control(csi);
> +	if (ret)
> +		goto err_async;

You'll also need to call v4l2_ctrl_handler_free() if setting up the handler
failed. I.e. just change the label here and remove err_async label below.

> +
> +	csi->format_mbus[CSI_PAD_SOURCE] = mei_csi_format_mbus_default;
> +	csi->format_mbus[CSI_PAD_SINK] = mei_csi_format_mbus_default;
> +
> +	csi->pads[CSI_PAD_SOURCE].flags = MEDIA_PAD_FL_SOURCE;
> +	csi->pads[CSI_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
> +	ret = media_entity_pads_init(&csi->subdev.entity, CSI_NUM_PADS,
> +				     csi->pads);
> +	if (ret)
> +		goto err_ctrl_handler;
> +
> +	ret = v4l2_subdev_init_finalize(&csi->subdev);
> +	if (ret < 0)
> +		goto err_entity;
> +
> +	ret = v4l2_async_register_subdev(&csi->subdev);
> +	if (ret < 0)
> +		goto err_subdev;
> +
> +	pm_runtime_enable(&cldev->dev);
> +
> +	return 0;
> +
> +err_subdev:
> +	v4l2_subdev_cleanup(&csi->subdev);
> +err_entity:
> +	media_entity_cleanup(&csi->subdev.entity);
> +err_ctrl_handler:
> +	v4l2_ctrl_handler_free(&csi->ctrl_handler);
> +err_async:
> +	v4l2_async_nf_unregister(&csi->notifier);
> +	v4l2_async_nf_cleanup(&csi->notifier);
> +err_disable:
> +	mei_cldev_disable(cldev);

It'd be nice to have an additional newline before the label. Elsewhere,
too.

> +destroy_mutex:
> +	mutex_destroy(&csi->lock);
> +
> +	return ret;
> +}
> +
> +static void mei_csi_remove(struct mei_cl_device *cldev)
> +{
> +	struct mei_csi *csi = mei_cldev_get_drvdata(cldev);
> +
> +	v4l2_async_nf_unregister(&csi->notifier);
> +	v4l2_async_nf_cleanup(&csi->notifier);
> +	v4l2_ctrl_handler_free(&csi->ctrl_handler);
> +	v4l2_async_unregister_subdev(&csi->subdev);
> +	v4l2_subdev_cleanup(&csi->subdev);
> +	media_entity_cleanup(&csi->subdev.entity);
> +
> +	pm_runtime_disable(&cldev->dev);
> +
> +	mutex_destroy(&csi->lock);
> +}
> +
> +#define MEI_CSI_UUID UUID_LE(0x92335FCF, 0x3203, 0x4472, \
> +			     0xAF, 0x93, 0x7b, 0x44, 0x53, 0xAC, 0x29, 0xDA)
> +
> +static const struct mei_cl_device_id mei_csi_tbl[] = {
> +	{ MEI_CSI_DRIVER_NAME, MEI_CSI_UUID, MEI_CL_VERSION_ANY },
> +

Extra newline.

> +	/* required last entry */

The comment could be on the same line below. E.g. "Sentinel" is
appropriate, as this isn't just any last entry.

> +	{ }
> +};
> +MODULE_DEVICE_TABLE(mei, mei_csi_tbl);
> +
> +static struct mei_cl_driver mei_csi_driver = {
> +	.id_table = mei_csi_tbl,
> +	.name = MEI_CSI_DRIVER_NAME,
> +
> +	.probe = mei_csi_probe,
> +	.remove = mei_csi_remove,
> +};
> +
> +module_mei_cl_driver(mei_csi_driver);
> +
> +MODULE_AUTHOR("Wentong Wu <wentong.wu@intel.com>");
> +MODULE_AUTHOR("Zhifeng Wang <zhifeng.wang@intel.com>");
> +MODULE_DESCRIPTION("Device driver for IVSC CSI");
> +MODULE_LICENSE("GPL");
Sakari Ailus March 29, 2023, 8:49 a.m. UTC | #3
Hi Wentong,

On Mon, Mar 27, 2023 at 02:23:06PM +0800, Wentong Wu wrote:
> diff --git a/drivers/media/pci/intel/ivsc/Kconfig b/drivers/media/pci/intel/ivsc/Kconfig
> new file mode 100644
> index 0000000..9535ac1
> --- /dev/null
> +++ b/drivers/media/pci/intel/ivsc/Kconfig
> @@ -0,0 +1,12 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +# Copyright (C) 2023, Intel Corporation. All rights reserved.
> +
> +config INTEL_VSC
> +	tristate "Intel Visual Sensing Controller"
> +	depends on INTEL_MEI

I think you should depend on PM here.

Alternatively, request host ownership from ace + csi in probe() if runtime
PM isn't enabled.

> +	help
> +	  This adds support for Intel Visual Sensing Controller (IVSC).
> +
> +	  Enables the IVSC firmware services required for controlling
> +	  camera sensor ownership and CSI-2 link through Image Processing
> +	  Unit(IPU) driver of Intel.
Sakari Ailus March 30, 2023, 8:23 a.m. UTC | #4
Hi Wentong,

On Thu, Mar 30, 2023 at 03:58:10AM +0000, Wu, Wentong wrote:
> Hi Sakari,
> 
> Thanks
> 
> > -----Original Message-----
> > From: Sakari Ailus <sakari.ailus@linux.intel.com>
> > Sent: Wednesday, March 29, 2023 4:49 PM
> > 
> > Hi Wentong,
> > 
> > On Mon, Mar 27, 2023 at 02:23:06PM +0800, Wentong Wu wrote:
> > > CSI is a submodule of IVSC which can route camera sensor data to the
> > > outbound MIPI CSI-2 interface.
> > >
> > > The interface communicating with firmware is via MEI. There is a
> > > separate MEI UUID, which this driver uses to enumerate.
> > >
> > > To route camera sensor data to host, the information of link frequency
> > > and number of data lanes is sent to firmware by sending MEI command
> > > when starting stream.
> > >
> > > CSI also provides a privacy mode. When privacy mode is turned on,
> > > camera sensor can't be used. This means that both IVSC and host Image
> > > Processing Unit(IPU) can't get image data. And when this mode is
> > > turned on, host Image Processing Unit(IPU) driver is informed via v4l2
> > > control callback, so that user can be notified.
> > >
> > > Signed-off-by: Wentong Wu <wentong.wu@intel.com>
> > > ---
> > >  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/csi_bridge.c | 332 +++++++++++++
> > > drivers/media/pci/intel/ivsc/csi_bridge.h | 122 +++++
> > >  drivers/media/pci/intel/ivsc/mei_csi.c    | 775
> > ++++++++++++++++++++++++++++++
> > >  7 files changed, 1251 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/csi_bridge.c
> > >  create mode 100644 drivers/media/pci/intel/ivsc/csi_bridge.h
> > >  create mode 100644 drivers/media/pci/intel/ivsc/mei_csi.c
> > 
> > I'm commenting just mei_csi this time...
> > 
> > > diff --git a/drivers/media/pci/intel/ivsc/mei_csi.c
> > > b/drivers/media/pci/intel/ivsc/mei_csi.c
> > > new file mode 100644
> > > index 0000000..6a01537
> > > --- /dev/null
> > > +++ b/drivers/media/pci/intel/ivsc/mei_csi.c
> > > @@ -0,0 +1,775 @@
> > > +// SPDX-License-Identifier: GPL-2.0-only
> > > +/*
> > > + * Copyright (C) 2023 Intel Corporation. All rights reserved.
> > > + * Intel Visual Sensing Controller CSI Linux driver  */
> > > +
> > > +/*
> > > + * To set ownership of CSI-2 link and to configure CSI-2 link, there
> > > + * are specific commands, which are sent via MEI protocol. The send
> > > + * command function uses "completion" as a synchronization mechanism.
> > > + * The response for command is received via a mei callback which
> > > +wakes
> > > + * up the caller. There can be only one outstanding command at a time.
> > > + */
> > > +
> > > +#include <linux/completion.h>
> > > +#include <linux/delay.h>
> > > +#include <linux/kernel.h>
> > > +#include <linux/math64.h>
> > > +#include <linux/mei_cl_bus.h>
> > > +#include <linux/module.h>
> > > +#include <linux/mutex.h>
> > > +#include <linux/pm_runtime.h>
> > > +#include <linux/slab.h>
> > > +#include <linux/units.h>
> > > +#include <linux/uuid.h>
> > > +#include <linux/workqueue.h>
> > > +
> > > +#include <media/v4l2-async.h>
> > > +#include <media/v4l2-ctrls.h>
> > > +#include <media/v4l2-fwnode.h>
> > > +#include <media/v4l2-subdev.h>
> > > +
> > > +#define MEI_CSI_DRIVER_NAME "ivsc_csi"
> > > +
> > > +/* the 5s used here is based on experiment */ #define CSI_CMD_TIMEOUT
> > > +(5 * HZ)
> > > +/* to setup CSI-2 link an extra delay needed and determined
> > > +experimentally */ #define CSI_FW_READY_DELAY_MS 100
> > > +/* link frequency unit is 100kHz */
> > > +#define CSI_LINK_FREQ(x) ((u32)(div_u64(x, 100 * HZ_PER_KHZ)))
> > > +
> > > +/*
> > > + * identify the command id supported by firmware
> > > + * IPC, as well as the privacy notification id
> > > + * used when processing privacy event.
> > > + */
> > > +enum csi_cmd_id {
> > > +	/* used to set csi ownership */
> > > +	CSI_SET_OWNER = 0,
> > > +
> > > +	/* used to configure CSI-2 link */
> > > +	CSI_SET_CONF = 2,
> > > +
> > > +	/* privacy notification id used when privacy state changes */
> > > +	CSI_PRIVACY_NOTIF = 6,
> > > +};
> > > +
> > > +/* CSI-2 link ownership definition */ enum csi_link_owner {
> > > +	CSI_LINK_IVSC,
> > > +	CSI_LINK_HOST,
> > > +};
> > > +
> > > +/* privacy status definition */
> > > +enum ivsc_privacy_status {
> > > +	CSI_PRIVACY_OFF,
> > > +	CSI_PRIVACY_ON,
> > > +	CSI_PRIVACY_MAX,
> > > +};
> > > +
> > > +enum csi_pads {
> > > +	CSI_PAD_SOURCE,
> > > +	CSI_PAD_SINK,
> > > +	CSI_NUM_PADS
> > > +};
> > > +
> > > +/* configuration of the CSI-2 link between host and IVSC */ struct
> > > +csi_link_cfg {
> > > +	/* number of data lanes used on the CSI-2 link */
> > > +	u32 nr_of_lanes;
> > > +
> > > +	/* frequency of the CSI-2 link */
> > > +	u32 link_freq;
> > > +
> > > +	/* for future use */
> > > +	u32 rsvd[2];
> > > +} __packed;
> > > +
> > > +/* CSI command structure */
> > > +struct csi_cmd {
> > > +	u32 cmd_id;
> > > +	union _cmd_param {
> > > +		u32 param;
> > > +		struct csi_link_cfg conf;
> > > +	} param;
> > > +} __packed;
> > > +
> > > +/* CSI notification structure */
> > > +struct csi_notif {
> > > +	u32 cmd_id;
> > > +	int status;
> > > +	union _resp_cont {
> > > +		u32 cont;
> > > +		struct csi_link_cfg conf;
> > > +	} cont;
> > > +} __packed;
> > > +
> > > +struct mei_csi {
> > > +	struct mei_cl_device *cldev;
> > > +
> > > +	/* command response */
> > > +	struct csi_notif cmd_response;
> > > +	/* used to wait for command response from firmware */
> > > +	struct completion cmd_completion;
> > > +	/* protect command download */
> > > +	struct mutex lock;
> > > +
> > > +	struct v4l2_subdev subdev;
> > > +	struct v4l2_subdev *remote;
> > > +	struct v4l2_async_notifier notifier;
> > > +	struct v4l2_ctrl_handler ctrl_handler;
> > > +	struct v4l2_ctrl *privacy_ctrl;
> > > +	unsigned int remote_pad;
> > > +	/* start streaming or not */
> > > +	int streaming;
> > > +
> > > +	struct media_pad pads[CSI_NUM_PADS];
> > > +	struct v4l2_mbus_framefmt format_mbus[CSI_NUM_PADS];
> > > +
> > > +	/* number of data lanes used on the CSI-2 link */
> > > +	u32 nr_of_lanes;
> > > +	/* frequency of the CSI-2 link */
> > > +	u64 link_freq;
> > > +
> > > +	/* privacy status */
> > > +	enum ivsc_privacy_status status;
> > > +};
> > > +
> > > +static const struct v4l2_mbus_framefmt mei_csi_format_mbus_default = {
> > > +	.width = 1,
> > > +	.height = 1,
> > > +	.code = MEDIA_BUS_FMT_Y8_1X8,
> > > +	.field = V4L2_FIELD_NONE,
> > > +};
> > > +
> > > +int csi_bridge_init(struct mei_cl_device *csi_dev);
> > > +
> > > +static inline struct mei_csi *notifier_to_csi(struct
> > > +v4l2_async_notifier *n) {
> > > +	return container_of(n, struct mei_csi, notifier); }
> > > +
> > > +static inline struct mei_csi *sd_to_csi(struct v4l2_subdev *sd) {
> > > +	return container_of(sd, struct mei_csi, subdev); }
> > > +
> > > +/* send a command to firmware and mutex must be held by caller */
> > > +static int mei_csi_send(struct mei_csi *csi, u8 *buf, size_t len) {
> > > +	struct csi_cmd *cmd = (struct csi_cmd *)buf;
> > > +	int ret;
> > > +
> > > +	reinit_completion(&csi->cmd_completion);
> > > +
> > > +	ret = mei_cldev_send(csi->cldev, buf, len);
> > > +	if (ret < 0)
> > > +		goto out;
> > > +
> > > +	ret = wait_for_completion_killable_timeout(&csi->cmd_completion,
> > > +						   CSI_CMD_TIMEOUT);
> > > +	if (ret < 0) {
> > > +		goto out;
> > > +	} else if (!ret) {
> > > +		ret = -ETIMEDOUT;
> > > +		goto out;
> > > +	}
> > > +
> > > +	/* command response status */
> > > +	ret = csi->cmd_response.status;
> > > +	if (ret) {
> > > +		ret = -EINVAL;
> > > +		goto out;
> > > +	}
> > > +
> > > +	if (csi->cmd_response.cmd_id != cmd->cmd_id)
> > > +		ret = -EINVAL;
> > > +
> > > +out:
> > > +	return ret;
> > > +}
> > > +
> > > +/* set CSI-2 link ownership */
> > > +static int csi_set_link_owner(struct mei_csi *csi, enum
> > > +csi_link_owner owner) {
> > > +	struct csi_cmd cmd = { 0 };
> > > +	size_t cmd_size;
> > > +	int ret;
> > > +
> > > +	cmd.cmd_id = CSI_SET_OWNER;
> > > +	cmd.param.param = owner;
> > > +	cmd_size = sizeof(cmd.cmd_id) + sizeof(cmd.param.param);
> > 
> > In some cases you're using memset and in others not. If you don't need memset,
> > I'd prefer assigning the fields in variable declaration instead.
> 
> The declaration will be like below, but it will break reverse x-mas tree style.

Have I asked to change your e-mail client settings?

> 
> struct csi_cmd cmd = { 0 };
> size_t cmd_size = sizeof(cmd.cmd_id) + sizeof(cmd.param.param);
> int ret;

It's not a problem if you have a dependency.

> 
> 
> > 
> > > +
> > > +	mutex_lock(&csi->lock);
> > > +
> > > +	ret = mei_csi_send(csi, (u8 *)&cmd, cmd_size);
> > > +
> > > +	mutex_unlock(&csi->lock);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +/* configure CSI-2 link between host and IVSC */ static int
> > > +csi_set_link_cfg(struct mei_csi *csi) {
> > > +	struct csi_cmd cmd = { 0 };
> > > +	size_t cmd_size;
> > > +	int ret;
> > > +
> > > +	cmd.cmd_id = CSI_SET_CONF;
> > > +	cmd.param.conf.nr_of_lanes = csi->nr_of_lanes;
> > > +	cmd.param.conf.link_freq = CSI_LINK_FREQ(csi->link_freq);
> > > +	cmd_size = sizeof(cmd.cmd_id) + sizeof(cmd.param.conf);
> > 
> > Ditto.
> > 
> > > +
> > > +	mutex_lock(&csi->lock);
> > > +
> > > +	ret = mei_csi_send(csi, (u8 *)&cmd, cmd_size);
> > > +	/*
> > > +	 * wait configuration ready if download success. placing
> > > +	 * delay under mutex is to make sure current command flow
> > > +	 * completed before starting a possible new one.
> > > +	 */
> > > +	if (!ret)
> > > +		msleep(CSI_FW_READY_DELAY_MS);
> > > +
> > > +	mutex_unlock(&csi->lock);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +/* callback for receive */
> > > +static void mei_csi_rx(struct mei_cl_device *cldev) {
> > > +	struct mei_csi *csi = mei_cldev_get_drvdata(cldev);
> > > +	struct csi_notif notif = { 0 };
> > > +	int ret;
> > > +
> > > +	ret = mei_cldev_recv(cldev, (u8 *)&notif, sizeof(notif));
> > > +	if (ret < 0) {
> > > +		dev_err(&cldev->dev, "recv error: %d\n", ret);
> > > +		return;
> > > +	}
> > > +
> > > +	switch (notif.cmd_id) {
> > > +	case CSI_PRIVACY_NOTIF:
> > > +		if (notif.cont.cont < CSI_PRIVACY_MAX) {
> > > +			csi->status = notif.cont.cont;
> > > +			v4l2_ctrl_s_ctrl(csi->privacy_ctrl, csi->status);
> > > +		}
> > > +		break;
> > > +	case CSI_SET_OWNER:
> > > +	case CSI_SET_CONF:
> > > +		memcpy(&csi->cmd_response, &notif, ret);
> > > +
> > > +		complete(&csi->cmd_completion);
> > > +		break;
> > > +	default:
> > > +		break;
> > > +	}
> > > +}
> > > +
> > > +static int mei_csi_pre_streamon(struct v4l2_subdev *sd, u32 flags) {
> > > +	struct v4l2_querymenu qm = { .id = V4L2_CID_LINK_FREQ, };
> > > +	struct v4l2_mbus_config mbus_config = { 0 };
> > > +	struct mei_csi *csi = sd_to_csi(sd);
> > > +	struct v4l2_ctrl *ctrl;
> > > +	int ret = 0;
> > > +
> > > +	if (!csi->remote)
> > > +		return -ENODEV;
> > > +
> > > +	ret = v4l2_subdev_call(csi->remote, pad, get_mbus_config,
> > > +			       csi->remote_pad, &mbus_config);
> > > +	if (ret)
> > > +		return ret;
> > 
> > You're already parsing the endpoint in probe(). Do you need this, assuming the
> > sensor has a static lane configuration? Virtually all do.
> 
> When parsing remote endpoint, just get num_data_lanes by
> v4l2_fwnode_endpoint_alloc_parse?

Yes.

> 
> > 
> > Could this all be done via the s_stream() op instead?
> 
> We don't need csi2 link freq and lane number when s_steam(0)

You can set the VOLATILE flag on the control and then query the upstream
sub-device in the g_ctrl callback.

> 
> > 
> > > +
> > > +	if (mbus_config.type != V4L2_MBUS_CSI2_DPHY)
> > > +		return -EINVAL;
> > > +
> > > +	csi->nr_of_lanes = mbus_config.bus.mipi_csi2.num_data_lanes;
> > > +
> > > +	ctrl = v4l2_ctrl_find(csi->remote->ctrl_handler, V4L2_CID_LINK_FREQ);
> > > +	if (!ctrl)
> > > +		return -EINVAL;
> > > +	qm.index = v4l2_ctrl_g_ctrl(ctrl);
> > > +
> > > +	ret = v4l2_querymenu(csi->remote->ctrl_handler, &qm);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	csi->link_freq = qm.value;
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static int mei_csi_set_stream(struct v4l2_subdev *sd, int enable) {
> > > +	struct mei_csi *csi = sd_to_csi(sd);
> > > +	int ret = 0;
> > > +
> > > +	if (enable && csi->streaming == 0) {
> > > +		/* switch CSI-2 link to host */
> > > +		ret = csi_set_link_owner(csi, CSI_LINK_HOST);
> > > +		if (ret < 0)
> > > +			goto err;
> > > +
> > > +		/* configure CSI-2 link */
> > > +		ret = csi_set_link_cfg(csi);
> > > +		if (ret < 0)
> > > +			goto err;
> > > +
> > > +		ret = v4l2_subdev_call(csi->remote, video, s_stream, 1);
> > > +		if (ret)
> > > +			goto err;
> > > +	} else if (!enable && csi->streaming == 1) {
> > > +		v4l2_subdev_call(csi->remote, video, s_stream, 0);
> > > +
> > > +		/* switch CSI-2 link to IVSC */
> > > +		ret = csi_set_link_owner(csi, CSI_LINK_IVSC);
> > > +		if (ret < 0)
> > > +			goto err;
> > 
> > I'd complain (e.g. dev_warn()) but return zero in this case. There's not much if
> > anything the caller can do with this.
> 
> ack
> > 
> > > +	}
> > > +
> > > +	csi->streaming = enable;
> > > +
> > > +err:
> > > +	return ret;
> > > +}
> > > +
> > > +static struct v4l2_mbus_framefmt *
> > > +mei_csi_get_pad_format(struct v4l2_subdev *sd,
> > > +		       struct v4l2_subdev_state *sd_state,
> > > +		       unsigned int pad, u32 which) {
> > > +	struct mei_csi *csi = sd_to_csi(sd);
> > > +
> > > +	switch (which) {
> > > +	case V4L2_SUBDEV_FORMAT_TRY:
> > > +		return v4l2_subdev_get_try_format(sd, sd_state, pad);
> > > +	case V4L2_SUBDEV_FORMAT_ACTIVE:
> > > +		return &csi->format_mbus[pad];
> > > +	default:
> > > +		return NULL;
> > > +	}
> > > +}
> > > +
> > > +static int mei_csi_init_cfg(struct v4l2_subdev *sd,
> > > +			    struct v4l2_subdev_state *sd_state) {
> > > +	struct v4l2_mbus_framefmt *mbusformat;
> > > +	struct mei_csi *csi = sd_to_csi(sd);
> > > +	unsigned int i;
> > > +
> > > +	mutex_lock(&csi->lock);
> > > +
> > > +	for (i = 0; i < sd->entity.num_pads; i++) {
> > > +		mbusformat = v4l2_subdev_get_try_format(sd, sd_state, i);
> > > +		*mbusformat = mei_csi_format_mbus_default;
> > > +	}
> > > +
> > > +	mutex_unlock(&csi->lock);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int mei_csi_get_fmt(struct v4l2_subdev *sd,
> > > +			   struct v4l2_subdev_state *sd_state,
> > > +			   struct v4l2_subdev_format *format) {
> > > +	struct v4l2_mbus_framefmt *mbusformat;
> > > +	struct mei_csi *csi = sd_to_csi(sd);
> > > +
> > > +	mutex_lock(&csi->lock);
> > > +
> > > +	mbusformat = mei_csi_get_pad_format(sd, sd_state, format->pad,
> > > +					    format->which);
> > > +	if (mbusformat)
> > > +		format->format = *mbusformat;
> > > +
> > > +	mutex_unlock(&csi->lock);
> > > +
> > > +	return 0;
> > > +}
> > 
> > It'd be nice to have also enum_mbus_code support. Video mux of course didn't
> > have this either. Something that could be done in the framework, including
> > validating the mbus format.
> 
> Sorry, you mean the default MEDIA_BUS_FMT_Y8_1X8?

Any format that can be supported by the device.

The video mux should have that, too. I'll see if this would fit to the
framework neatly somehow.

> 
> > 
> > > +
> > > +static int mei_csi_set_fmt(struct v4l2_subdev *sd,
> > > +			   struct v4l2_subdev_state *sd_state,
> > > +			   struct v4l2_subdev_format *format) {
> > > +	struct v4l2_mbus_framefmt *source_mbusformat;
> > > +	struct v4l2_mbus_framefmt *mbusformat;
> > > +	struct mei_csi *csi = sd_to_csi(sd);
> > > +	struct media_pad *pad;
> > > +
> > > +	mbusformat = mei_csi_get_pad_format(sd, sd_state, format->pad,
> > > +					    format->which);
> > > +	if (!mbusformat)
> > > +		return -EINVAL;
> > > +
> > > +	source_mbusformat = mei_csi_get_pad_format(sd, sd_state,
> > > +						   CSI_PAD_SOURCE,
> > > +						   format->which);
> > > +	if (!source_mbusformat)
> > > +		return -EINVAL;
> > > +
> > > +	v4l_bound_align_image(&format->format.width, 1, 65536, 0,
> > > +			      &format->format.height, 1, 65536, 0, 0);
> > > +
> > > +	switch (format->format.code) {
> > > +	case MEDIA_BUS_FMT_RGB444_1X12:
> > > +	case MEDIA_BUS_FMT_RGB444_2X8_PADHI_BE:
> > > +	case MEDIA_BUS_FMT_RGB444_2X8_PADHI_LE:
> > > +	case MEDIA_BUS_FMT_RGB555_2X8_PADHI_BE:
> > > +	case MEDIA_BUS_FMT_RGB555_2X8_PADHI_LE:
> > > +	case MEDIA_BUS_FMT_RGB565_1X16:
> > > +	case MEDIA_BUS_FMT_BGR565_2X8_BE:
> > > +	case MEDIA_BUS_FMT_BGR565_2X8_LE:
> > > +	case MEDIA_BUS_FMT_RGB565_2X8_BE:
> > > +	case MEDIA_BUS_FMT_RGB565_2X8_LE:
> > > +	case MEDIA_BUS_FMT_RGB666_1X18:
> > > +	case MEDIA_BUS_FMT_RBG888_1X24:
> > > +	case MEDIA_BUS_FMT_RGB666_1X24_CPADHI:
> > > +	case MEDIA_BUS_FMT_BGR888_1X24:
> > > +	case MEDIA_BUS_FMT_GBR888_1X24:
> > > +	case MEDIA_BUS_FMT_RGB888_1X24:
> > > +	case MEDIA_BUS_FMT_RGB888_2X12_BE:
> > > +	case MEDIA_BUS_FMT_RGB888_2X12_LE:
> > > +	case MEDIA_BUS_FMT_ARGB8888_1X32:
> > > +	case MEDIA_BUS_FMT_RGB888_1X32_PADHI:
> > > +	case MEDIA_BUS_FMT_RGB101010_1X30:
> > > +	case MEDIA_BUS_FMT_RGB121212_1X36:
> > > +	case MEDIA_BUS_FMT_RGB161616_1X48:
> > > +	case MEDIA_BUS_FMT_Y8_1X8:
> > > +	case MEDIA_BUS_FMT_UV8_1X8:
> > > +	case MEDIA_BUS_FMT_UYVY8_1_5X8:
> > > +	case MEDIA_BUS_FMT_VYUY8_1_5X8:
> > > +	case MEDIA_BUS_FMT_YUYV8_1_5X8:
> > > +	case MEDIA_BUS_FMT_YVYU8_1_5X8:
> > > +	case MEDIA_BUS_FMT_UYVY8_2X8:
> > > +	case MEDIA_BUS_FMT_VYUY8_2X8:
> > > +	case MEDIA_BUS_FMT_YUYV8_2X8:
> > > +	case MEDIA_BUS_FMT_YVYU8_2X8:
> > > +	case MEDIA_BUS_FMT_Y10_1X10:
> > > +	case MEDIA_BUS_FMT_UYVY10_2X10:
> > > +	case MEDIA_BUS_FMT_VYUY10_2X10:
> > > +	case MEDIA_BUS_FMT_YUYV10_2X10:
> > > +	case MEDIA_BUS_FMT_YVYU10_2X10:
> > > +	case MEDIA_BUS_FMT_Y12_1X12:
> > > +	case MEDIA_BUS_FMT_UYVY12_2X12:
> > > +	case MEDIA_BUS_FMT_VYUY12_2X12:
> > > +	case MEDIA_BUS_FMT_YUYV12_2X12:
> > > +	case MEDIA_BUS_FMT_YVYU12_2X12:
> > > +	case MEDIA_BUS_FMT_UYVY8_1X16:
> > > +	case MEDIA_BUS_FMT_VYUY8_1X16:
> > > +	case MEDIA_BUS_FMT_YUYV8_1X16:
> > > +	case MEDIA_BUS_FMT_YVYU8_1X16:
> > > +	case MEDIA_BUS_FMT_YDYUYDYV8_1X16:
> > > +	case MEDIA_BUS_FMT_UYVY10_1X20:
> > > +	case MEDIA_BUS_FMT_VYUY10_1X20:
> > > +	case MEDIA_BUS_FMT_YUYV10_1X20:
> > > +	case MEDIA_BUS_FMT_YVYU10_1X20:
> > > +	case MEDIA_BUS_FMT_VUY8_1X24:
> > > +	case MEDIA_BUS_FMT_YUV8_1X24:
> > > +	case MEDIA_BUS_FMT_UYYVYY8_0_5X24:
> > > +	case MEDIA_BUS_FMT_UYVY12_1X24:
> > > +	case MEDIA_BUS_FMT_VYUY12_1X24:
> > > +	case MEDIA_BUS_FMT_YUYV12_1X24:
> > > +	case MEDIA_BUS_FMT_YVYU12_1X24:
> > > +	case MEDIA_BUS_FMT_YUV10_1X30:
> > > +	case MEDIA_BUS_FMT_UYYVYY10_0_5X30:
> > > +	case MEDIA_BUS_FMT_AYUV8_1X32:
> > > +	case MEDIA_BUS_FMT_UYYVYY12_0_5X36:
> > > +	case MEDIA_BUS_FMT_YUV12_1X36:
> > > +	case MEDIA_BUS_FMT_YUV16_1X48:
> > > +	case MEDIA_BUS_FMT_UYYVYY16_0_5X48:
> > > +	case MEDIA_BUS_FMT_JPEG_1X8:
> > > +	case MEDIA_BUS_FMT_AHSV8888_1X32:
> > > +	case MEDIA_BUS_FMT_SBGGR8_1X8:
> > > +	case MEDIA_BUS_FMT_SGBRG8_1X8:
> > > +	case MEDIA_BUS_FMT_SGRBG8_1X8:
> > > +	case MEDIA_BUS_FMT_SRGGB8_1X8:
> > > +	case MEDIA_BUS_FMT_SBGGR10_1X10:
> > > +	case MEDIA_BUS_FMT_SGBRG10_1X10:
> > > +	case MEDIA_BUS_FMT_SGRBG10_1X10:
> > > +	case MEDIA_BUS_FMT_SRGGB10_1X10:
> > > +	case MEDIA_BUS_FMT_SBGGR12_1X12:
> > > +	case MEDIA_BUS_FMT_SGBRG12_1X12:
> > > +	case MEDIA_BUS_FMT_SGRBG12_1X12:
> > > +	case MEDIA_BUS_FMT_SRGGB12_1X12:
> > > +	case MEDIA_BUS_FMT_SBGGR14_1X14:
> > > +	case MEDIA_BUS_FMT_SGBRG14_1X14:
> > > +	case MEDIA_BUS_FMT_SGRBG14_1X14:
> > > +	case MEDIA_BUS_FMT_SRGGB14_1X14:
> > > +	case MEDIA_BUS_FMT_SBGGR16_1X16:
> > > +	case MEDIA_BUS_FMT_SGBRG16_1X16:
> > > +	case MEDIA_BUS_FMT_SGRBG16_1X16:
> > > +	case MEDIA_BUS_FMT_SRGGB16_1X16:
> > > +		break;
> > > +	default:
> > > +		format->format.code = MEDIA_BUS_FMT_Y8_1X8;
> > > +		break;
> > > +	}
> > > +	if (format->format.field == V4L2_FIELD_ANY)
> > > +		format->format.field = V4L2_FIELD_NONE;
> > > +
> > > +	mutex_lock(&csi->lock);
> > > +
> > > +	pad = &csi->pads[format->pad];
> > > +	if (pad->flags & MEDIA_PAD_FL_SOURCE)
> > > +		format->format = csi->format_mbus[CSI_PAD_SINK];
> > > +
> > > +	*mbusformat = format->format;
> > > +
> > > +	if (pad->flags & MEDIA_PAD_FL_SINK)
> > > +		*source_mbusformat = format->format;
> > > +
> > > +	mutex_unlock(&csi->lock);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static const struct v4l2_subdev_video_ops mei_csi_video_ops = {
> > > +	.s_stream = mei_csi_set_stream,
> > > +	.pre_streamon = mei_csi_pre_streamon, };
> > > +
> > > +static const struct v4l2_subdev_pad_ops mei_csi_pad_ops = {
> > > +	.init_cfg = mei_csi_init_cfg,
> > > +	.get_fmt = mei_csi_get_fmt,
> > > +	.set_fmt = mei_csi_set_fmt,
> > > +};
> > > +
> > > +static const struct v4l2_subdev_ops mei_csi_subdev_ops = {
> > > +	.video = &mei_csi_video_ops,
> > > +	.pad = &mei_csi_pad_ops,
> > > +};
> > > +
> > > +static const struct media_entity_operations mei_csi_entity_ops = {
> > > +	.link_validate = v4l2_subdev_link_validate, };
> > > +
> > > +static int mei_csi_notify_bound(struct v4l2_async_notifier *notifier,
> > > +				struct v4l2_subdev *subdev,
> > > +				struct v4l2_async_subdev *asd)
> > > +{
> > > +	struct mei_csi *csi = notifier_to_csi(notifier);
> > > +	int pad;
> > > +
> > > +	pad = media_entity_get_fwnode_pad(&subdev->entity, asd-
> > >match.fwnode,
> > > +					  MEDIA_PAD_FL_SOURCE);
> > > +	if (pad < 0)
> > > +		return pad;
> > > +
> > > +	csi->remote = subdev;
> > > +	csi->remote_pad = pad;
> > > +
> > > +	return media_create_pad_link(&subdev->entity, pad,
> > > +				     &csi->subdev.entity, 0,
> > > +				     MEDIA_LNK_FL_ENABLED |
> > > +				     MEDIA_LNK_FL_IMMUTABLE);
> > > +}
> > > +
> > > +static void mei_csi_notify_unbind(struct v4l2_async_notifier *notifier,
> > > +				  struct v4l2_subdev *subdev,
> > > +				  struct v4l2_async_subdev *asd)
> > > +{
> > > +	struct mei_csi *csi = notifier_to_csi(notifier);
> > > +
> > > +	csi->remote = NULL;
> > > +}
> > > +
> > > +static const struct v4l2_async_notifier_operations mei_csi_notify_ops = {
> > > +	.bound = mei_csi_notify_bound,
> > > +	.unbind = mei_csi_notify_unbind,
> > > +};
> > > +
> > > +static int mei_csi_init_control(struct mei_csi *csi) {
> > > +	v4l2_ctrl_handler_init(&csi->ctrl_handler, 1);
> > > +	csi->ctrl_handler.lock = &csi->lock;
> > > +
> > > +	csi->privacy_ctrl = v4l2_ctrl_new_std(&csi->ctrl_handler, NULL,
> > > +					      V4L2_CID_PRIVACY, 0, 1, 1, 0);
> > > +	if (csi->ctrl_handler.error)
> > > +		return csi->ctrl_handler.error;
> > 
> > The control should be made volatile here (flags |=

Read-only, I meant. Volatile is for controls that are not driven by
hardware events somehow.

> > V4L2_CTRL_FLAG_READ_ONLY) as it can't be changed by the user.
> 
> ack
> > 
> > > +
> > > +	csi->subdev.ctrl_handler = &csi->ctrl_handler;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int mei_csi_parse_firmware(struct mei_csi *csi) {
> > > +	struct v4l2_fwnode_endpoint v4l2_ep = {
> > > +		.bus_type = V4L2_MBUS_CSI2_DPHY,
> > > +	};
> > > +	struct device *dev = &csi->cldev->dev;
> > > +	struct v4l2_async_subdev *asd;
> > > +	struct fwnode_handle *fwnode;
> > > +	struct fwnode_handle *ep;
> > > +	int ret;
> > > +
> > > +	ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev), 0, 0, 0);
> > > +	if (!ep) {
> > > +		dev_err(dev, "not connected to subdevice\n");
> > > +		return -EINVAL;
> > > +	}
> > > +
> > > +	ret = v4l2_fwnode_endpoint_parse(ep, &v4l2_ep);
> > > +	if (ret) {
> > > +		dev_err(dev, "could not parse v4l2 endpoint\n");
> > > +		fwnode_handle_put(ep);
> > > +		return -EINVAL;
> > > +	}
> > > +
> > > +	fwnode = fwnode_graph_get_remote_endpoint(ep);
> > > +	fwnode_handle_put(ep);
> > > +
> > > +	v4l2_async_nf_init(&csi->notifier);
> > > +	csi->notifier.ops = &mei_csi_notify_ops;
> > > +
> > > +	asd = v4l2_async_nf_add_fwnode(&csi->notifier, fwnode,
> > > +				       struct v4l2_async_subdev);
> > > +	fwnode_handle_put(fwnode);
> > > +	if (IS_ERR(asd))
> > > +		return PTR_ERR(asd);
> > > +
> > > +	ret = v4l2_async_subdev_nf_register(&csi->subdev, &csi->notifier);
> > > +	if (ret)
> > > +		v4l2_async_nf_cleanup(&csi->notifier);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static int mei_csi_probe(struct mei_cl_device *cldev,
> > > +			 const struct mei_cl_device_id *id) {
> > > +	struct mei_csi *csi;
> > > +	int ret;
> > > +
> > > +	/*
> > > +	 * no connections to sensor are defined in firmware, try to
> > > +	 * build connections as software_nodes parsed from SSDB.
> > > +	 */
> > > +	ret = csi_bridge_init(cldev);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	csi = devm_kzalloc(&cldev->dev, sizeof(struct mei_csi), GFP_KERNEL);
> > > +	if (!csi)
> > > +		return -ENOMEM;
> > > +
> > > +	csi->cldev = cldev;
> > > +	mutex_init(&csi->lock);
> > > +	init_completion(&csi->cmd_completion);
> > > +
> > > +	mei_cldev_set_drvdata(cldev, csi);
> > > +
> > > +	ret = mei_cldev_enable(cldev);
> > > +	if (ret < 0) {
> > > +		dev_err(&cldev->dev, "mei_cldev_enable failed: %d\n", ret);
> > > +		goto destroy_mutex;
> > > +	}
> > > +
> > > +	ret = mei_cldev_register_rx_cb(cldev, mei_csi_rx);
> > > +	if (ret) {
> > > +		dev_err(&cldev->dev, "event cb registration failed: %d\n", ret);
> > > +		goto err_disable;
> > > +	}
> > > +
> > > +	ret = mei_csi_parse_firmware(csi);
> > > +	if (ret)
> > > +		goto err_disable;
> > > +
> > > +	csi->subdev.dev = &cldev->dev;
> > > +	v4l2_subdev_init(&csi->subdev, &mei_csi_subdev_ops);
> > > +	v4l2_set_subdevdata(&csi->subdev, csi);
> > > +	csi->subdev.flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
> > > +	csi->subdev.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
> > > +	csi->subdev.entity.ops = &mei_csi_entity_ops;
> > > +
> > > +	ret = mei_csi_init_control(csi);
> > > +	if (ret)
> > > +		goto err_async;
> > 
> > You'll also need to call v4l2_ctrl_handler_free() if setting up the handler failed.
> > I.e. just change the label here and remove err_async label below.
> Thanks
> > 
> > > +
> > > +	csi->format_mbus[CSI_PAD_SOURCE] = mei_csi_format_mbus_default;
> > > +	csi->format_mbus[CSI_PAD_SINK] = mei_csi_format_mbus_default;
> > > +
> > > +	csi->pads[CSI_PAD_SOURCE].flags = MEDIA_PAD_FL_SOURCE;
> > > +	csi->pads[CSI_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
> > > +	ret = media_entity_pads_init(&csi->subdev.entity, CSI_NUM_PADS,
> > > +				     csi->pads);
> > > +	if (ret)
> > > +		goto err_ctrl_handler;
> > > +
> > > +	ret = v4l2_subdev_init_finalize(&csi->subdev);
> > > +	if (ret < 0)
> > > +		goto err_entity;
> > > +
> > > +	ret = v4l2_async_register_subdev(&csi->subdev);
> > > +	if (ret < 0)
> > > +		goto err_subdev;
> > > +
> > > +	pm_runtime_enable(&cldev->dev);
> > > +
> > > +	return 0;
> > > +
> > > +err_subdev:
> > > +	v4l2_subdev_cleanup(&csi->subdev);
> > > +err_entity:
> > > +	media_entity_cleanup(&csi->subdev.entity);
> > > +err_ctrl_handler:
> > > +	v4l2_ctrl_handler_free(&csi->ctrl_handler);
> > > +err_async:
> > > +	v4l2_async_nf_unregister(&csi->notifier);
> > > +	v4l2_async_nf_cleanup(&csi->notifier);
> > > +err_disable:
> > > +	mei_cldev_disable(cldev);
> > 
> > It'd be nice to have an additional newline before the label. Elsewhere, too.
> ack
> > 
> > > +destroy_mutex:
> > > +	mutex_destroy(&csi->lock);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static void mei_csi_remove(struct mei_cl_device *cldev) {
> > > +	struct mei_csi *csi = mei_cldev_get_drvdata(cldev);
> > > +
> > > +	v4l2_async_nf_unregister(&csi->notifier);
> > > +	v4l2_async_nf_cleanup(&csi->notifier);
> > > +	v4l2_ctrl_handler_free(&csi->ctrl_handler);
> > > +	v4l2_async_unregister_subdev(&csi->subdev);
> > > +	v4l2_subdev_cleanup(&csi->subdev);
> > > +	media_entity_cleanup(&csi->subdev.entity);
> > > +
> > > +	pm_runtime_disable(&cldev->dev);
> > > +
> > > +	mutex_destroy(&csi->lock);
> > > +}
> > > +
> > > +#define MEI_CSI_UUID UUID_LE(0x92335FCF, 0x3203, 0x4472, \
> > > +			     0xAF, 0x93, 0x7b, 0x44, 0x53, 0xAC, 0x29, 0xDA)
> > > +
> > > +static const struct mei_cl_device_id mei_csi_tbl[] = {
> > > +	{ MEI_CSI_DRIVER_NAME, MEI_CSI_UUID, MEI_CL_VERSION_ANY },
> > > +
> > 
> > Extra newline.
> > 
> > > +	/* required last entry */
> > 
> > The comment could be on the same line below. E.g. "Sentinel" is appropriate, as
> > this isn't just any last entry.
> thanks
> > 
> > > +	{ }
> > > +};
> > > +MODULE_DEVICE_TABLE(mei, mei_csi_tbl);
> > > +
> > > +static struct mei_cl_driver mei_csi_driver = {
> > > +	.id_table = mei_csi_tbl,
> > > +	.name = MEI_CSI_DRIVER_NAME,
> > > +
> > > +	.probe = mei_csi_probe,
> > > +	.remove = mei_csi_remove,
> > > +};
> > > +
> > > +module_mei_cl_driver(mei_csi_driver);
> > > +
> > > +MODULE_AUTHOR("Wentong Wu <wentong.wu@intel.com>");
> > > +MODULE_AUTHOR("Zhifeng Wang <zhifeng.wang@intel.com>");
> > > +MODULE_DESCRIPTION("Device driver for IVSC CSI");
> > > +MODULE_LICENSE("GPL");
> >