diff mbox series

[v2,12/12] ipu3-cio2: Add cio2-bridge to ipu3-cio2 driver

Message ID 20201217234337.1983732-13-djrscally@gmail.com (mailing list archive)
State Superseded, archived
Headers show
Series Add functionality to ipu3-cio2 driver allowing software_node connections to sensors on platforms designed for Windows | expand

Commit Message

Daniel Scally Dec. 17, 2020, 11:43 p.m. UTC
Currently on platforms designed for Windows, connections between CIO2 and
sensors are not properly defined in DSDT. This patch extends the ipu3-cio2
driver to compensate by building software_node connections, parsing the
connection properties from the sensor's SSDB buffer.

Suggested-by: Jordan Hand <jorhand@linux.microsoft.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
---
Changes in v2:

	- Dropped some headers
	- Added support for specifying link-frequencies in the array of
	cio2_supported_sensors and added that property to the endpoint.
	- Replaced strcpy with strscpy (Laurent, I liked your change better
	stylistically but ofc the string literals are lost when the module
	is reloaded)
	- Named the ports/endpoints "port@%u"
	- Added an overflow check to cio2_bridge_connect_sensors()
	- A bunch of cosmetic changes

For the cio2_supported_sensors array, specify link frequencies in this
manner: 

	CIO2_SENSOR_CONFIG("OVTI5648", 2, 16800000, 2100000)

 MAINTAINERS                                   |   1 +
 drivers/media/pci/intel/ipu3/Kconfig          |  18 ++
 drivers/media/pci/intel/ipu3/Makefile         |   1 +
 drivers/media/pci/intel/ipu3/cio2-bridge.c    | 274 ++++++++++++++++++
 drivers/media/pci/intel/ipu3/cio2-bridge.h    | 122 ++++++++
 drivers/media/pci/intel/ipu3/ipu3-cio2-main.c |  34 +++
 drivers/media/pci/intel/ipu3/ipu3-cio2.h      |   6 +
 7 files changed, 456 insertions(+)
 create mode 100644 drivers/media/pci/intel/ipu3/cio2-bridge.c
 create mode 100644 drivers/media/pci/intel/ipu3/cio2-bridge.h

Comments

Laurent Pinchart Dec. 18, 2020, 4:53 p.m. UTC | #1
Hi Daniel,

Thank you for the patch.

On Thu, Dec 17, 2020 at 11:43:37PM +0000, Daniel Scally wrote:
> Currently on platforms designed for Windows, connections between CIO2 and
> sensors are not properly defined in DSDT. This patch extends the ipu3-cio2
> driver to compensate by building software_node connections, parsing the
> connection properties from the sensor's SSDB buffer.
> 
> Suggested-by: Jordan Hand <jorhand@linux.microsoft.com>
> Signed-off-by: Daniel Scally <djrscally@gmail.com>
> ---
> Changes in v2:
> 
> 	- Dropped some headers
> 	- Added support for specifying link-frequencies in the array of
> 	cio2_supported_sensors and added that property to the endpoint.
> 	- Replaced strcpy with strscpy (Laurent, I liked your change better
> 	stylistically but ofc the string literals are lost when the module
> 	is reloaded)
> 	- Named the ports/endpoints "port@%u"
> 	- Added an overflow check to cio2_bridge_connect_sensors()
> 	- A bunch of cosmetic changes
> 
> For the cio2_supported_sensors array, specify link frequencies in this
> manner: 
> 
> 	CIO2_SENSOR_CONFIG("OVTI5648", 2, 16800000, 2100000)
> 
>  MAINTAINERS                                   |   1 +
>  drivers/media/pci/intel/ipu3/Kconfig          |  18 ++
>  drivers/media/pci/intel/ipu3/Makefile         |   1 +
>  drivers/media/pci/intel/ipu3/cio2-bridge.c    | 274 ++++++++++++++++++
>  drivers/media/pci/intel/ipu3/cio2-bridge.h    | 122 ++++++++
>  drivers/media/pci/intel/ipu3/ipu3-cio2-main.c |  34 +++
>  drivers/media/pci/intel/ipu3/ipu3-cio2.h      |   6 +
>  7 files changed, 456 insertions(+)
>  create mode 100644 drivers/media/pci/intel/ipu3/cio2-bridge.c
>  create mode 100644 drivers/media/pci/intel/ipu3/cio2-bridge.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 16b544624577..e7784b4bc8ea 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -8943,6 +8943,7 @@ INTEL IPU3 CSI-2 CIO2 DRIVER
>  M:	Yong Zhi <yong.zhi@intel.com>
>  M:	Sakari Ailus <sakari.ailus@linux.intel.com>
>  M:	Bingbu Cao <bingbu.cao@intel.com>
> +M:	Dan Scally <djrscally@gmail.com>
>  R:	Tianshu Qiu <tian.shu.qiu@intel.com>
>  L:	linux-media@vger.kernel.org
>  S:	Maintained
> diff --git a/drivers/media/pci/intel/ipu3/Kconfig b/drivers/media/pci/intel/ipu3/Kconfig
> index 82d7f17e6a02..dcf5c4b74673 100644
> --- a/drivers/media/pci/intel/ipu3/Kconfig
> +++ b/drivers/media/pci/intel/ipu3/Kconfig
> @@ -16,3 +16,21 @@ config VIDEO_IPU3_CIO2
>  	  Say Y or M here if you have a Skylake/Kaby Lake SoC with MIPI CSI-2
>  	  connected camera.
>  	  The module will be called ipu3-cio2.
> +
> +config CIO2_BRIDGE
> +	bool "IPU3 CIO2 Sensors Bridge"
> +	depends on VIDEO_IPU3_CIO2
> +	help
> +	  This extension provides an API for the ipu3-cio2 driver to create
> +	  connections to cameras that are hidden in SSDB buffer in ACPI. It
> +	  can be used to enable support for cameras in detachable / hybrid
> +	  devices that ship with Windows.
> +
> +	  Say Y here if your device is a detachable / hybrid laptop that comes
> +	  with Windows installed by the OEM, for example:
> +
> +		- Microsoft Surface models (except Surface Pro 3)
> +		- The Lenovo Miix line (for example the 510, 520, 710 and 720)
> +		- Dell 7285
> +
> +	  If in doubt, say N here.
> diff --git a/drivers/media/pci/intel/ipu3/Makefile b/drivers/media/pci/intel/ipu3/Makefile
> index 429d516452e4..933777e6ea8a 100644
> --- a/drivers/media/pci/intel/ipu3/Makefile
> +++ b/drivers/media/pci/intel/ipu3/Makefile
> @@ -2,3 +2,4 @@
>  obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2.o
>  
>  ipu3-cio2-y += ipu3-cio2-main.o
> +ipu3-cio2-$(CONFIG_CIO2_BRIDGE) += cio2-bridge.o
> diff --git a/drivers/media/pci/intel/ipu3/cio2-bridge.c b/drivers/media/pci/intel/ipu3/cio2-bridge.c
> new file mode 100644
> index 000000000000..3f0e2d7eab20
> --- /dev/null
> +++ b/drivers/media/pci/intel/ipu3/cio2-bridge.c
> @@ -0,0 +1,274 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Author: Dan Scally <djrscally@gmail.com> */
> +
> +#include <linux/acpi.h>
> +#include <linux/device.h>
> +#include <linux/pci.h>
> +#include <linux/property.h>
> +
> +#include "cio2-bridge.h"
> +
> +/*
> + * Extend this array with ACPI Hardware ID's of devices known to be working
> + * plus the number of link-frequencies expected by their drivers, along with
> + * the frequency values in hertz. This is somewhat opportunistic way of adding
> + * support for this for now in the hopes of a better source for the information
> + * (possibly some encoded value in the SSDB buffer that we're unaware of)
> + * becoming apparent in the future.
> + *
> + * Do not add an entry for a sensor that is not actually supported.
> + */
> +static const struct cio2_sensor_config cio2_supported_sensors[] = {
> +	CIO2_SENSOR_CONFIG("INT33BE", 0),
> +	CIO2_SENSOR_CONFIG("OVTI2680", 0),
> +};
> +
> +static int cio2_bridge_read_acpi_buffer(struct acpi_device *adev, char *id,
> +					void *data, u32 size)
> +{
> +	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> +	union acpi_object *obj;
> +	acpi_status status;
> +	int ret;
> +
> +	status = acpi_evaluate_object(adev->handle, id, NULL, &buffer);
> +	if (ACPI_FAILURE(status))
> +		return -ENODEV;
> +
> +	obj = buffer.pointer;
> +	if (!obj) {
> +		dev_err(&adev->dev, "Couldn't locate ACPI buffer\n");
> +		return -ENODEV;
> +	}
> +
> +	if (obj->type != ACPI_TYPE_BUFFER) {
> +		dev_err(&adev->dev, "Not an ACPI buffer\n");
> +		ret = -ENODEV;
> +		goto out_free_buff;
> +	}
> +
> +	if (obj->buffer.length > size) {
> +		dev_err(&adev->dev, "Given buffer is too small\n");
> +		ret = -EINVAL;
> +		goto out_free_buff;
> +	}
> +
> +	memcpy(data, obj->buffer.pointer, obj->buffer.length);
> +	ret = obj->buffer.length;
> +
> +out_free_buff:
> +	kfree(buffer.pointer);
> +	return ret;
> +}
> +
> +static void cio2_bridge_init_property_names(struct cio2_sensor *sensor)
> +{
> +	strscpy(sensor->prop_names.clock_frequency, "clock-frequency",
> +		sizeof(sensor->prop_names.clock_frequency));
> +	strscpy(sensor->prop_names.rotation, "rotation",
> +		sizeof(sensor->prop_names.rotation));
> +	strscpy(sensor->prop_names.bus_type, "bus-type",
> +		sizeof(sensor->prop_names.bus_type));
> +	strscpy(sensor->prop_names.data_lanes, "data-lanes",
> +		sizeof(sensor->prop_names.data_lanes));
> +	strscpy(sensor->prop_names.remote_endpoint, "remote-endpoint",
> +		sizeof(sensor->prop_names.remote_endpoint));
> +	strscpy(sensor->prop_names.link_frequencies, "link-frequencies",
> +		sizeof(sensor->prop_names.link_frequencies));

Just curious, was there anything not working correctly with the proposal
I made ?

static const struct cio2_property_names prop_names = {
	.clock_frequency = "clock-frequency",
	.rotation = "rotation",
	.bus_type = "bus-type",
	.data_lanes = "data-lanes",
	.remote_endpoint = "remote-endpoint",
};

static void cio2_bridge_init_property_names(struct cio2_sensor *sensor)
{
	sensor->prop_names = prop_names;
}

It generates a warning when the string is too long for the field size,
which should help catching issues at compilation time.

> +}
> +
> +static void cio2_bridge_create_fwnode_properties(struct cio2_sensor *sensor,
> +						 const struct cio2_sensor_config *cfg)
> +{
> +	unsigned int i;
> +
> +	cio2_bridge_init_property_names(sensor);
> +
> +	for (i = 0; i < 4; i++)
> +		sensor->data_lanes[i] = i + 1;
> +
> +	sensor->local_ref[0].node = &sensor->swnodes[SWNODE_CIO2_ENDPOINT];
> +	sensor->remote_ref[0].node = &sensor->swnodes[SWNODE_SENSOR_ENDPOINT];
> +
> +	sensor->dev_properties[0] = PROPERTY_ENTRY_U32(sensor->prop_names.clock_frequency,
> +						       sensor->ssdb.mclkspeed);
> +	sensor->dev_properties[1] = PROPERTY_ENTRY_U8(sensor->prop_names.rotation,
> +						      sensor->ssdb.degree);
> +
> +	sensor->ep_properties[0] = PROPERTY_ENTRY_U32(sensor->prop_names.bus_type, 4);
> +	sensor->ep_properties[1] = PROPERTY_ENTRY_U32_ARRAY_LEN(sensor->prop_names.data_lanes,
> +								sensor->data_lanes,
> +								sensor->ssdb.lanes);
> +	sensor->ep_properties[2] = PROPERTY_ENTRY_REF_ARRAY(sensor->prop_names.remote_endpoint,
> +							    sensor->local_ref);
> +
> +	if (cfg->nr_link_freqs > 0)
> +		sensor->ep_properties[3] = PROPERTY_ENTRY_U64_ARRAY_LEN(
> +						sensor->prop_names.link_frequencies,
> +						cfg->link_freqs,
> +						cfg->nr_link_freqs);
> +
> +	sensor->cio2_properties[0] = PROPERTY_ENTRY_U32_ARRAY_LEN(sensor->prop_names.data_lanes,
> +								  sensor->data_lanes,
> +								  sensor->ssdb.lanes);
> +	sensor->cio2_properties[1] = PROPERTY_ENTRY_REF_ARRAY(sensor->prop_names.remote_endpoint,
> +							      sensor->remote_ref);
> +}
> +
> +static void cio2_bridge_init_swnode_names(struct cio2_sensor *sensor)
> +{
> +	snprintf(sensor->node_names.remote_port, 7, "port@%u", sensor->ssdb.link);
> +	strscpy(sensor->node_names.port, "port@0", sizeof(sensor->node_names.port));
> +	strscpy(sensor->node_names.endpoint, "endpoint@0", sizeof(sensor->node_names.endpoint));

I'd wrap lines, but maybe that's because I'm an old-school, 80-columns
programmer :-)

> +}
> +
> +static void cio2_bridge_create_connection_swnodes(struct cio2_bridge *bridge,
> +						  struct cio2_sensor *sensor)
> +{
> +	struct software_node *nodes = sensor->swnodes;
> +
> +	cio2_bridge_init_swnode_names(sensor);
> +
> +	nodes[SWNODE_SENSOR_HID] = NODE_SENSOR(sensor->name,
> +					       sensor->dev_properties);
> +	nodes[SWNODE_SENSOR_PORT] = NODE_PORT(sensor->node_names.port,
> +					      &nodes[SWNODE_SENSOR_HID]);
> +	nodes[SWNODE_SENSOR_ENDPOINT] = NODE_ENDPOINT(sensor->node_names.endpoint,
> +						      &nodes[SWNODE_SENSOR_PORT],
> +						      sensor->ep_properties);
> +	nodes[SWNODE_CIO2_PORT] = NODE_PORT(sensor->node_names.remote_port,
> +					    &bridge->cio2_hid_node);
> +	nodes[SWNODE_CIO2_ENDPOINT] = NODE_ENDPOINT(sensor->node_names.endpoint,
> +						    &nodes[SWNODE_CIO2_PORT],
> +						    sensor->cio2_properties);
> +}
> +
> +static void cio2_bridge_unregister_sensors(struct cio2_bridge *bridge)
> +{
> +	struct cio2_sensor *sensor;
> +	unsigned int i;
> +
> +	for (i = 0; i < bridge->n_sensors; i++) {
> +		sensor = &bridge->sensors[i];
> +		software_node_unregister_nodes(sensor->swnodes);
> +		acpi_dev_put(sensor->adev);
> +	}
> +}
> +
> +static int cio2_bridge_connect_sensors(struct cio2_bridge *bridge,
> +				       struct pci_dev *cio2)
> +{
> +	struct fwnode_handle *fwnode;
> +	struct cio2_sensor *sensor;
> +	struct acpi_device *adev;
> +	unsigned int i;
> +	int ret = 0;
> +
> +	for (i = 0; i < ARRAY_SIZE(cio2_supported_sensors); i++) {
> +		const struct cio2_sensor_config *cfg = &cio2_supported_sensors[i];
> +
> +		for_each_acpi_dev_match(adev, cfg->hid, NULL, -1) {
> +			if (bridge->n_sensors >= CIO2_NUM_PORTS) {
> +				dev_warn(&cio2->dev, "Exceeded available CIO2 ports\n");
> +				/* overflow i so outer loop ceases */
> +				i = ARRAY_SIZE(cio2_supported_sensors);
> +				break;

Or just

				return 0;

?

> +			}
> +
> +			if (!adev->status.enabled)
> +				continue;
> +
> +			sensor = &bridge->sensors[bridge->n_sensors];
> +			sensor->adev = adev;
> +			strscpy(sensor->name, cfg->hid, sizeof(sensor->name));
> +
> +			ret = cio2_bridge_read_acpi_buffer(adev, "SSDB",
> +							   &sensor->ssdb,
> +							   sizeof(sensor->ssdb));
> +			if (ret < 0)
> +				goto err_put_adev;
> +
> +			if (sensor->ssdb.lanes > 4) {
> +				dev_err(&adev->dev,
> +					"Number of lanes in SSDB is invalid\n");
> +				goto err_put_adev;
> +			}
> +
> +			cio2_bridge_create_fwnode_properties(sensor, cfg);
> +			cio2_bridge_create_connection_swnodes(bridge, sensor);
> +
> +			ret = software_node_register_nodes(sensor->swnodes);
> +			if (ret)
> +				goto err_put_adev;
> +
> +			fwnode = software_node_fwnode(&sensor->swnodes[SWNODE_SENSOR_HID]);
> +			if (!fwnode) {
> +				ret = -ENODEV;
> +				goto err_free_swnodes;
> +			}
> +
> +			adev->fwnode.secondary = fwnode;
> +
> +			dev_info(&cio2->dev, "Found supported sensor %s\n",
> +				 acpi_dev_name(adev));
> +
> +			bridge->n_sensors++;
> +		}
> +	}
> +
> +	return ret;
> +
> +err_free_swnodes:
> +	software_node_unregister_nodes(sensor->swnodes);
> +err_put_adev:
> +	acpi_dev_put(sensor->adev);
> +
> +	return ret;
> +}
> +
> +int cio2_bridge_init(struct pci_dev *cio2)
> +{
> +	struct device *dev = &cio2->dev;
> +	struct fwnode_handle *fwnode;
> +	struct cio2_bridge *bridge;
> +	int ret;
> +
> +	bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
> +	if (!bridge)
> +		return -ENOMEM;
> +
> +	strscpy(bridge->cio2_node_name, CIO2_HID, sizeof(bridge->cio2_node_name));
> +	bridge->cio2_hid_node.name = bridge->cio2_node_name;
> +
> +	ret = software_node_register(&bridge->cio2_hid_node);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to register the CIO2 HID node\n");
> +		goto err_free_bridge;
> +	}
> +
> +	ret = cio2_bridge_connect_sensors(bridge, cio2);
> +	if (ret || bridge->n_sensors == 0)
> +		goto err_unregister_cio2;
> +
> +	dev_info(dev, "Connected %d cameras\n", bridge->n_sensors);
> +
> +	fwnode = software_node_fwnode(&bridge->cio2_hid_node);
> +	if (!fwnode) {
> +		dev_err(dev, "Error getting fwnode from cio2 software_node\n");
> +		ret = -ENODEV;
> +		goto err_unregister_sensors;
> +	}
> +
> +	set_secondary_fwnode(dev, fwnode);
> +
> +	return 0;
> +
> +err_unregister_sensors:
> +	cio2_bridge_unregister_sensors(bridge);
> +err_unregister_cio2:
> +	software_node_unregister(&bridge->cio2_hid_node);
> +err_free_bridge:
> +	kfree(bridge);
> +
> +	return ret;
> +}
> diff --git a/drivers/media/pci/intel/ipu3/cio2-bridge.h b/drivers/media/pci/intel/ipu3/cio2-bridge.h
> new file mode 100644
> index 000000000000..f89a8e33f82c
> --- /dev/null
> +++ b/drivers/media/pci/intel/ipu3/cio2-bridge.h
> @@ -0,0 +1,122 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Author: Dan Scally <djrscally@gmail.com> */
> +#ifndef __CIO2_BRIDGE_H
> +#define __CIO2_BRIDGE_H
> +
> +#include <linux/property.h>
> +
> +#define CIO2_HID				"INT343E"
> +#define CIO2_NUM_PORTS				4
> +#define MAX_NUM_LINK_FREQS			3
> +
> +#define CIO2_SENSOR_CONFIG(_HID, _NR, ...)	\
> +	{					\
> +		.hid = _HID,			\
> +		.nr_link_freqs = _NR,		\
> +		.link_freqs = { __VA_ARGS__ }	\
> +	}
> +
> +#define NODE_SENSOR(_HID, _PROPS)		\
> +	((const struct software_node) {		\
> +		.name = _HID,			\
> +		.properties = _PROPS,		\
> +	})
> +
> +#define NODE_PORT(_PORT, _SENSOR_NODE)		\
> +	((const struct software_node) {		\
> +		_PORT,				\
> +		_SENSOR_NODE,			\
> +	})
> +
> +#define NODE_ENDPOINT(_EP, _PORT, _PROPS)	\
> +	((const struct software_node) {		\
> +		_EP,				\
> +		_PORT,				\
> +		_PROPS,				\
> +	})
> +
> +enum cio2_sensor_swnodes {
> +	SWNODE_SENSOR_HID,
> +	SWNODE_SENSOR_PORT,
> +	SWNODE_SENSOR_ENDPOINT,
> +	SWNODE_CIO2_PORT,
> +	SWNODE_CIO2_ENDPOINT,
> +	NR_OF_SENSOR_SWNODES
> +};
> +
> +/* Data representation as it is in ACPI SSDB buffer */
> +struct cio2_sensor_ssdb {
> +	u8 version;				/* 0000 */
> +	u8 sku;					/* 0001 */
> +	u8 guid_csi2[16];			/* 0002 */
> +	u8 devfunction;				/* 0003 */
> +	u8 bus;					/* 0004 */
> +	u32 dphylinkenfuses;			/* 0005 */
> +	u32 clockdiv;				/* 0009 */
> +	u8 link;				/* 0013 */
> +	u8 lanes;				/* 0014 */
> +	u32 csiparams[10];			/* 0015 */
> +	u32 maxlanespeed;			/* 0019 */
> +	u8 sensorcalibfileidx;			/* 0023 */
> +	u8 sensorcalibfileidxInMBZ[3];		/* 0024 */
> +	u8 romtype;				/* 0025 */
> +	u8 vcmtype;				/* 0026 */
> +	u8 platforminfo;			/* 0027 */

Why stop at 27 ? :-) I'd either go all the way, or not at all. It's also
quite customary to represent offset as hex values, as that's what most
hex editors / viewers will show.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> +	u8 platformsubinfo;
> +	u8 flash;
> +	u8 privacyled;
> +	u8 degree;
> +	u8 mipilinkdefined;
> +	u32 mclkspeed;
> +	u8 controllogicid;
> +	u8 reserved1[3];
> +	u8 mclkport;
> +	u8 reserved2[13];
> +} __packed;
> +
> +struct cio2_property_names {
> +	char clock_frequency[16];
> +	char rotation[9];
> +	char bus_type[9];
> +	char data_lanes[11];
> +	char remote_endpoint[16];
> +	char link_frequencies[17];
> +};
> +
> +struct cio2_node_names {
> +	char port[7];
> +	char endpoint[11];
> +	char remote_port[7];
> +};
> +
> +struct cio2_sensor_config {
> +	const char *hid;
> +	const u8 nr_link_freqs;
> +	const u64 link_freqs[MAX_NUM_LINK_FREQS];
> +};
> +
> +struct cio2_sensor {
> +	char name[ACPI_ID_LEN];
> +	struct acpi_device *adev;
> +
> +	struct software_node swnodes[6];
> +	struct cio2_node_names node_names;
> +
> +	u32 data_lanes[4];
> +	struct cio2_sensor_ssdb ssdb;
> +	struct cio2_property_names prop_names;
> +	struct property_entry ep_properties[5];
> +	struct property_entry dev_properties[3];
> +	struct property_entry cio2_properties[3];
> +	struct software_node_ref_args local_ref[1];
> +	struct software_node_ref_args remote_ref[1];
> +};
> +
> +struct cio2_bridge {
> +	char cio2_node_name[ACPI_ID_LEN];
> +	struct software_node cio2_hid_node;
> +	unsigned int n_sensors;
> +	struct cio2_sensor sensors[CIO2_NUM_PORTS];
> +};
> +
> +#endif
> diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
> index 36e354ecf71e..68ff28abc6a3 100644
> --- a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
> +++ b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
> @@ -1702,11 +1702,28 @@ static void cio2_queues_exit(struct cio2_device *cio2)
>  		cio2_queue_exit(cio2, &cio2->queue[i]);
>  }
>  
> +static bool cio2_check_fwnode_graph(struct fwnode_handle *fwnode)
> +{
> +	struct fwnode_handle *endpoint;
> +
> +	if (IS_ERR_OR_NULL(fwnode))
> +		return false;
> +
> +	endpoint = fwnode_graph_get_next_endpoint(fwnode, NULL);
> +	if (endpoint) {
> +		fwnode_handle_put(endpoint);
> +		return true;
> +	}
> +
> +	return cio2_check_fwnode_graph(fwnode->secondary);
> +}
> +
>  /**************** PCI interface ****************/
>  
>  static int cio2_pci_probe(struct pci_dev *pci_dev,
>  			  const struct pci_device_id *id)
>  {
> +	struct fwnode_handle *fwnode = dev_fwnode(&pci_dev->dev);
>  	struct cio2_device *cio2;
>  	int r;
>  
> @@ -1715,6 +1732,23 @@ static int cio2_pci_probe(struct pci_dev *pci_dev,
>  		return -ENOMEM;
>  	cio2->pci_dev = pci_dev;
>  
> +	/*
> +	 * On some platforms no connections to sensors are defined in firmware,
> +	 * if the device has no endpoints then we can try to build those as
> +	 * software_nodes parsed from SSDB.
> +	 */
> +	if (!cio2_check_fwnode_graph(fwnode)) {
> +		if (fwnode && !IS_ERR_OR_NULL(fwnode->secondary)) {
> +			dev_err(&pci_dev->dev,
> +				"fwnode graph has no endpoints connected\n");
> +			return -EINVAL;
> +		}
> +
> +		r = cio2_bridge_init(pci_dev);
> +		if (r)
> +			return r;
> +	}
> +
>  	r = pcim_enable_device(pci_dev);
>  	if (r) {
>  		dev_err(&pci_dev->dev, "failed to enable device (%d)\n", r);
> diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2.h b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
> index ccf0b85ae36f..520a27c9cdad 100644
> --- a/drivers/media/pci/intel/ipu3/ipu3-cio2.h
> +++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
> @@ -437,4 +437,10 @@ static inline struct cio2_queue *vb2q_to_cio2_queue(struct vb2_queue *vq)
>  	return container_of(vq, struct cio2_queue, vbq);
>  }
>  
> +#if IS_ENABLED(CONFIG_CIO2_BRIDGE)
> +int cio2_bridge_init(struct pci_dev *cio2);
> +#else
> +int cio2_bridge_init(struct pci_dev *cio2) { return 0; }
> +#endif
> +
>  #endif
Andy Shevchenko Dec. 18, 2020, 9:17 p.m. UTC | #2
On Thu, Dec 17, 2020 at 11:43:37PM +0000, Daniel Scally wrote:
> Currently on platforms designed for Windows, connections between CIO2 and
> sensors are not properly defined in DSDT. This patch extends the ipu3-cio2
> driver to compensate by building software_node connections, parsing the
> connection properties from the sensor's SSDB buffer.

...

> +	sensor->ep_properties[0] = PROPERTY_ENTRY_U32(sensor->prop_names.bus_type, 4);

Does 4 has any meaning that can be described by #define ?

...

> +static void cio2_bridge_init_swnode_names(struct cio2_sensor *sensor)
> +{
> +	snprintf(sensor->node_names.remote_port, 7, "port@%u", sensor->ssdb.link);

Hmm... I think you should use actual size of remote_port instead of 7.

> +	strscpy(sensor->node_names.port, "port@0", sizeof(sensor->node_names.port));

Yeah, I would rather like to see one point of the definition of the format.
If it's the same as per OF case, perhaps some generic header (like fwnode.h?) is good for this?
In this case the 5 in one of the previous patches Also can be derived from the format.

> +	strscpy(sensor->node_names.endpoint, "endpoint@0", sizeof(sensor->node_names.endpoint));

Similar here.

> +}

...

> +	for (i = 0; i < ARRAY_SIZE(cio2_supported_sensors); i++) {
> +		const struct cio2_sensor_config *cfg = &cio2_supported_sensors[i];
> +
> +		for_each_acpi_dev_match(adev, cfg->hid, NULL, -1) {

> +			if (bridge->n_sensors >= CIO2_NUM_PORTS) {
> +				dev_warn(&cio2->dev, "Exceeded available CIO2 ports\n");

> +				/* overflow i so outer loop ceases */
> +				i = ARRAY_SIZE(cio2_supported_sensors);
> +				break;

Why not to create a new label below and assign ret here with probably comment
why it's not an error?

> +			}

...

> +			ret = cio2_bridge_read_acpi_buffer(adev, "SSDB",
> +							   &sensor->ssdb,
> +							   sizeof(sensor->ssdb));
> +			if (ret < 0)

if (ret) (because positive case can be returned just by next conditional).

> +				goto err_put_adev;
> +
> +			if (sensor->ssdb.lanes > 4) {
> +				dev_err(&adev->dev,
> +					"Number of lanes in SSDB is invalid\n");
> +				goto err_put_adev;
> +			}

...

> +			dev_info(&cio2->dev, "Found supported sensor %s\n",
> +				 acpi_dev_name(adev));
> +
> +			bridge->n_sensors++;
> +		}
> +	}

	return 0;

> +err_free_swnodes:
> +	software_node_unregister_nodes(sensor->swnodes);
> +err_put_adev:
> +	acpi_dev_put(sensor->adev);

err_out:

> +	return ret;
> +}

...

> +enum cio2_sensor_swnodes {
> +	SWNODE_SENSOR_HID,
> +	SWNODE_SENSOR_PORT,
> +	SWNODE_SENSOR_ENDPOINT,
> +	SWNODE_CIO2_PORT,
> +	SWNODE_CIO2_ENDPOINT,

> +	NR_OF_SENSOR_SWNODES

Perhaps same namespace, i.e.

	SWNODE_SENSOR_NR

> +};
Daniel Scally Dec. 18, 2020, 11:57 p.m. UTC | #3
Hi Laurent - thanks for the comments

On 18/12/2020 16:53, Laurent Pinchart wrote:
>> +static void cio2_bridge_init_property_names(struct cio2_sensor *sensor)
>> +{
>> +	strscpy(sensor->prop_names.clock_frequency, "clock-frequency",
>> +		sizeof(sensor->prop_names.clock_frequency));
>> +	strscpy(sensor->prop_names.rotation, "rotation",
>> +		sizeof(sensor->prop_names.rotation));
>> +	strscpy(sensor->prop_names.bus_type, "bus-type",
>> +		sizeof(sensor->prop_names.bus_type));
>> +	strscpy(sensor->prop_names.data_lanes, "data-lanes",
>> +		sizeof(sensor->prop_names.data_lanes));
>> +	strscpy(sensor->prop_names.remote_endpoint, "remote-endpoint",
>> +		sizeof(sensor->prop_names.remote_endpoint));
>> +	strscpy(sensor->prop_names.link_frequencies, "link-frequencies",
>> +		sizeof(sensor->prop_names.link_frequencies));
> 
> Just curious, was there anything not working correctly with the proposal
> I made ?
> 
> static const struct cio2_property_names prop_names = {
> 	.clock_frequency = "clock-frequency",
> 	.rotation = "rotation",
> 	.bus_type = "bus-type",
> 	.data_lanes = "data-lanes",
> 	.remote_endpoint = "remote-endpoint",
> };
> 
> static void cio2_bridge_init_property_names(struct cio2_sensor *sensor)
> {
> 	sensor->prop_names = prop_names;
> }
> 
> It generates a warning when the string is too long for the field size,
> which should help catching issues at compilation time.

Yes, though I don't know how much of a real-world problem it would have
been - if you recall we have the issue that the device grabs a reference
to the software_nodes (after we stopped delaying until after the
i2c_client is available), which means we can't safely free the
cio2_bridge struct on module unload. That also means we can't rely on
those pointers to string literals existing, because if the ipu3-cio2
module gets unloaded they'll be gone.

Shame, as it's way neater.

>> +static void cio2_bridge_init_swnode_names(struct cio2_sensor *sensor)
>> +{
>> +	snprintf(sensor->node_names.remote_port, 7, "port@%u", sensor->ssdb.link);
>> +	strscpy(sensor->node_names.port, "port@0", sizeof(sensor->node_names.port));
>> +	strscpy(sensor->node_names.endpoint, "endpoint@0", sizeof(sensor->node_names.endpoint));
> 
> I'd wrap lines, but maybe that's because I'm an old-school, 80-columns
> programmer :-)

Heh sure, I'll wrap them.

>> +static int cio2_bridge_connect_sensors(struct cio2_bridge *bridge,
>> +				       struct pci_dev *cio2)
>> +{
>> +	struct fwnode_handle *fwnode;
>> +	struct cio2_sensor *sensor;
>> +	struct acpi_device *adev;
>> +	unsigned int i;
>> +	int ret = 0;
>> +
>> +	for (i = 0; i < ARRAY_SIZE(cio2_supported_sensors); i++) {
>> +		const struct cio2_sensor_config *cfg = &cio2_supported_sensors[i];
>> +
>> +		for_each_acpi_dev_match(adev, cfg->hid, NULL, -1) {
>> +			if (bridge->n_sensors >= CIO2_NUM_PORTS) {
>> +				dev_warn(&cio2->dev, "Exceeded available CIO2 ports\n");
>> +				/* overflow i so outer loop ceases */
>> +				i = ARRAY_SIZE(cio2_supported_sensors);
>> +				break;
> 
> Or just
> 
> 				return 0;
> 
> ?

Derp, yes of course.


>> +/* Data representation as it is in ACPI SSDB buffer */
>> +struct cio2_sensor_ssdb {
>> +	u8 version;				/* 0000 */
>> +	u8 sku;					/* 0001 */
>> +	u8 guid_csi2[16];			/* 0002 */
>> +	u8 devfunction;				/* 0003 */
>> +	u8 bus;					/* 0004 */
>> +	u32 dphylinkenfuses;			/* 0005 */
>> +	u32 clockdiv;				/* 0009 */
>> +	u8 link;				/* 0013 */
>> +	u8 lanes;				/* 0014 */
>> +	u32 csiparams[10];			/* 0015 */
>> +	u32 maxlanespeed;			/* 0019 */
>> +	u8 sensorcalibfileidx;			/* 0023 */
>> +	u8 sensorcalibfileidxInMBZ[3];		/* 0024 */
>> +	u8 romtype;				/* 0025 */
>> +	u8 vcmtype;				/* 0026 */
>> +	u8 platforminfo;			/* 0027 */
> 
> Why stop at 27 ? :-) I'd either go all the way, or not at all. It's also
> quite customary to represent offset as hex values, as that's what most
> hex editors / viewers will show.

Oops - that was actually just me debugging...I guess I might actually
finish it, converted to hex. It came in useful reading the DSDT to have
that somewhere easy to refer to.

> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Nice - thank you!
Daniel Scally Dec. 19, 2020, 12:22 a.m. UTC | #4
Hi Andy, thanks for the comments

On 18/12/2020 21:17, Andy Shevchenko wrote:
> On Thu, Dec 17, 2020 at 11:43:37PM +0000, Daniel Scally wrote:
>> Currently on platforms designed for Windows, connections between CIO2 and
>> sensors are not properly defined in DSDT. This patch extends the ipu3-cio2
>> driver to compensate by building software_node connections, parsing the
>> connection properties from the sensor's SSDB buffer.
> 
> ...
> 
>> +	sensor->ep_properties[0] = PROPERTY_ENTRY_U32(sensor->prop_names.bus_type, 4);
> 
> Does 4 has any meaning that can be described by #define ?

It's V4L2_FWNODE_BUS_TYPE_CSI2_DPHY:

https://elixir.bootlin.com/linux/latest/source/drivers/media/v4l2-core/v4l2-fwnode.c#L36

That enum's not in an accessible header, but I can define it in this
module's header

>> +static void cio2_bridge_init_swnode_names(struct cio2_sensor *sensor)
>> +{
>> +	snprintf(sensor->node_names.remote_port, 7, "port@%u", sensor->ssdb.link);
> 
> Hmm... I think you should use actual size of remote_port instead of 7.

Yes ok


>> +	strscpy(sensor->node_names.port, "port@0", sizeof(sensor->node_names.port));
> 
> Yeah, I would rather like to see one point of the definition of the format.
> If it's the same as per OF case, perhaps some generic header (like fwnode.h?) is good for this?
> In this case the 5 in one of the previous patches Also can be derived from the format.

Okedokey. It is indeed intended to match OF and ACPI case, both of which
mandate that format (though only ACPI's functions seem to enforce it).
fwnode.h seems as good a place as any to me, though I'm not sure there's
anywhere in the driver code for OF or ACPI that would actually use it at
the moment.

>> +	strscpy(sensor->node_names.endpoint, "endpoint@0", sizeof(sensor->node_names.endpoint));
> 
> Similar here.
> 
>> +}
> 
> ...
> 
>> +	for (i = 0; i < ARRAY_SIZE(cio2_supported_sensors); i++) {
>> +		const struct cio2_sensor_config *cfg = &cio2_supported_sensors[i];
>> +
>> +		for_each_acpi_dev_match(adev, cfg->hid, NULL, -1) {
> 
>> +			if (bridge->n_sensors >= CIO2_NUM_PORTS) {
>> +				dev_warn(&cio2->dev, "Exceeded available CIO2 ports\n");
> 
>> +				/* overflow i so outer loop ceases */
>> +				i = ARRAY_SIZE(cio2_supported_sensors);
>> +				break;
> 
> Why not to create a new label below and assign ret here with probably comment
> why it's not an error?

Sure, I can do that, but since it wouldn't need any cleanup I could also
just return 0 here as Laurent suggest (but with a comment explaining why
that's ok as you say) - do you have a preference?

>> +			}
> 
> ...
> 
>> +			ret = cio2_bridge_read_acpi_buffer(adev, "SSDB",
>> +							   &sensor->ssdb,
>> +							   sizeof(sensor->ssdb));
>> +			if (ret < 0)
> 
> if (ret) (because positive case can be returned just by next conditional).

cio2_bridge_read_acpi_buffer() returns the buffer length on success at
the moment, but I can change it to return 0 and have this be if (ret)

>> +				goto err_put_adev;
>> +
>> +			if (sensor->ssdb.lanes > 4) {
>> +				dev_err(&adev->dev,
>> +					"Number of lanes in SSDB is invalid\n");
>> +				goto err_put_adev;
>> +			}
> 
> ...
> 
>> +			dev_info(&cio2->dev, "Found supported sensor %s\n",
>> +				 acpi_dev_name(adev));
>> +
>> +			bridge->n_sensors++;
>> +		}
>> +	}
> 
> 	return 0;

Okedokey

> 
>> +err_free_swnodes:
>> +	software_node_unregister_nodes(sensor->swnodes);
>> +err_put_adev:
>> +	acpi_dev_put(sensor->adev);
> 
> err_out:

Depends on question above I think

>> +	return ret;
>> +}
> 
> ...
> 
>> +enum cio2_sensor_swnodes {
>> +	SWNODE_SENSOR_HID,
>> +	SWNODE_SENSOR_PORT,
>> +	SWNODE_SENSOR_ENDPOINT,
>> +	SWNODE_CIO2_PORT,
>> +	SWNODE_CIO2_ENDPOINT,
> 
>> +	NR_OF_SENSOR_SWNODES
> 
> Perhaps same namespace, i.e.
> 
> 	SWNODE_SENSOR_NR

Yep, will do.

Thanks
Dan
Laurent Pinchart Dec. 19, 2020, 12:39 a.m. UTC | #5
Hi Daniel,

On Fri, Dec 18, 2020 at 11:57:54PM +0000, Daniel Scally wrote:
> Hi Laurent - thanks for the comments
> 
> On 18/12/2020 16:53, Laurent Pinchart wrote:
> >> +static void cio2_bridge_init_property_names(struct cio2_sensor *sensor)
> >> +{
> >> +	strscpy(sensor->prop_names.clock_frequency, "clock-frequency",
> >> +		sizeof(sensor->prop_names.clock_frequency));
> >> +	strscpy(sensor->prop_names.rotation, "rotation",
> >> +		sizeof(sensor->prop_names.rotation));
> >> +	strscpy(sensor->prop_names.bus_type, "bus-type",
> >> +		sizeof(sensor->prop_names.bus_type));
> >> +	strscpy(sensor->prop_names.data_lanes, "data-lanes",
> >> +		sizeof(sensor->prop_names.data_lanes));
> >> +	strscpy(sensor->prop_names.remote_endpoint, "remote-endpoint",
> >> +		sizeof(sensor->prop_names.remote_endpoint));
> >> +	strscpy(sensor->prop_names.link_frequencies, "link-frequencies",
> >> +		sizeof(sensor->prop_names.link_frequencies));
> > 
> > Just curious, was there anything not working correctly with the proposal
> > I made ?
> > 
> > static const struct cio2_property_names prop_names = {
> > 	.clock_frequency = "clock-frequency",
> > 	.rotation = "rotation",
> > 	.bus_type = "bus-type",
> > 	.data_lanes = "data-lanes",
> > 	.remote_endpoint = "remote-endpoint",
> > };
> > 
> > static void cio2_bridge_init_property_names(struct cio2_sensor *sensor)
> > {
> > 	sensor->prop_names = prop_names;
> > }
> > 
> > It generates a warning when the string is too long for the field size,
> > which should help catching issues at compilation time.
> 
> Yes, though I don't know how much of a real-world problem it would have
> been - if you recall we have the issue that the device grabs a reference
> to the software_nodes (after we stopped delaying until after the
> i2c_client is available), which means we can't safely free the
> cio2_bridge struct on module unload. That also means we can't rely on
> those pointers to string literals existing, because if the ipu3-cio2
> module gets unloaded they'll be gone.

But the strings above are not stored as literals in .rodata, they're
copied in prop_names (itself in .rodata), which is then copied to
sensor->prop_names.

> Shame, as it's way neater.
> 
> >> +static void cio2_bridge_init_swnode_names(struct cio2_sensor *sensor)
> >> +{
> >> +	snprintf(sensor->node_names.remote_port, 7, "port@%u", sensor->ssdb.link);
> >> +	strscpy(sensor->node_names.port, "port@0", sizeof(sensor->node_names.port));
> >> +	strscpy(sensor->node_names.endpoint, "endpoint@0", sizeof(sensor->node_names.endpoint));
> > 
> > I'd wrap lines, but maybe that's because I'm an old-school, 80-columns
> > programmer :-)
> 
> Heh sure, I'll wrap them.
> 
> >> +static int cio2_bridge_connect_sensors(struct cio2_bridge *bridge,
> >> +				       struct pci_dev *cio2)
> >> +{
> >> +	struct fwnode_handle *fwnode;
> >> +	struct cio2_sensor *sensor;
> >> +	struct acpi_device *adev;
> >> +	unsigned int i;
> >> +	int ret = 0;
> >> +
> >> +	for (i = 0; i < ARRAY_SIZE(cio2_supported_sensors); i++) {
> >> +		const struct cio2_sensor_config *cfg = &cio2_supported_sensors[i];
> >> +
> >> +		for_each_acpi_dev_match(adev, cfg->hid, NULL, -1) {
> >> +			if (bridge->n_sensors >= CIO2_NUM_PORTS) {
> >> +				dev_warn(&cio2->dev, "Exceeded available CIO2 ports\n");
> >> +				/* overflow i so outer loop ceases */
> >> +				i = ARRAY_SIZE(cio2_supported_sensors);
> >> +				break;
> > 
> > Or just
> > 
> > 				return 0;
> > 
> > ?
> 
> Derp, yes of course.
> 
> 
> >> +/* Data representation as it is in ACPI SSDB buffer */
> >> +struct cio2_sensor_ssdb {
> >> +	u8 version;				/* 0000 */
> >> +	u8 sku;					/* 0001 */
> >> +	u8 guid_csi2[16];			/* 0002 */
> >> +	u8 devfunction;				/* 0003 */
> >> +	u8 bus;					/* 0004 */
> >> +	u32 dphylinkenfuses;			/* 0005 */
> >> +	u32 clockdiv;				/* 0009 */
> >> +	u8 link;				/* 0013 */
> >> +	u8 lanes;				/* 0014 */
> >> +	u32 csiparams[10];			/* 0015 */
> >> +	u32 maxlanespeed;			/* 0019 */
> >> +	u8 sensorcalibfileidx;			/* 0023 */
> >> +	u8 sensorcalibfileidxInMBZ[3];		/* 0024 */
> >> +	u8 romtype;				/* 0025 */
> >> +	u8 vcmtype;				/* 0026 */
> >> +	u8 platforminfo;			/* 0027 */
> > 
> > Why stop at 27 ? :-) I'd either go all the way, or not at all. It's also
> > quite customary to represent offset as hex values, as that's what most
> > hex editors / viewers will show.
> 
> Oops - that was actually just me debugging...I guess I might actually
> finish it, converted to hex. It came in useful reading the DSDT to have
> that somewhere easy to refer to.
> 
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> Nice - thank you!
Andy Shevchenko Dec. 19, 2020, 6:52 p.m. UTC | #6
On Sat, Dec 19, 2020 at 2:25 AM Daniel Scally <djrscally@gmail.com> wrote:
> On 18/12/2020 21:17, Andy Shevchenko wrote:
> > On Thu, Dec 17, 2020 at 11:43:37PM +0000, Daniel Scally wrote:

...

> >> +    sensor->ep_properties[0] = PROPERTY_ENTRY_U32(sensor->prop_names.bus_type, 4);
> >
> > Does 4 has any meaning that can be described by #define ?
>
> It's V4L2_FWNODE_BUS_TYPE_CSI2_DPHY:
>
> https://elixir.bootlin.com/linux/latest/source/drivers/media/v4l2-core/v4l2-fwnode.c#L36
>
> That enum's not in an accessible header, but I can define it in this
> module's header

Maybe you can do a preparatory patch to make it visible to v4l2
drivers? (Like moving to one of v4l2 headers)

...

> >> +                    if (bridge->n_sensors >= CIO2_NUM_PORTS) {
> >> +                            dev_warn(&cio2->dev, "Exceeded available CIO2 ports\n");
> >
> >> +                            /* overflow i so outer loop ceases */
> >> +                            i = ARRAY_SIZE(cio2_supported_sensors);
> >> +                            break;
> >
> > Why not to create a new label below and assign ret here with probably comment
> > why it's not an error?
>
> Sure, I can do that, but since it wouldn't need any cleanup I could also
> just return 0 here as Laurent suggest (but with a comment explaining why
> that's ok as you say) - do you have a preference?

While it's a good suggestion it will bring a bit of inconsistency into
approach. Everywhere else in the function you are using the goto
approach.
So yes, I have a preference.

> >> +                    }

...

> >> +                    ret = cio2_bridge_read_acpi_buffer(adev, "SSDB",
> >> +                                                       &sensor->ssdb,
> >> +                                                       sizeof(sensor->ssdb));
> >> +                    if (ret < 0)
> >
> > if (ret) (because positive case can be returned just by next conditional).
>
> cio2_bridge_read_acpi_buffer() returns the buffer length on success at
> the moment, but I can change it to return 0 and have this be if (ret)

Please correct this somehow, because the next failure returns it
instead of error...

> >> +                            goto err_put_adev;
> >> +
> >> +                    if (sensor->ssdb.lanes > 4) {
> >> +                            dev_err(&adev->dev,
> >> +                                    "Number of lanes in SSDB is invalid\n");

...I'm even thinking that you have to assign ret here to something meaningful.

> >> +                            goto err_put_adev;
> >> +                    }
Daniel Scally Dec. 19, 2020, 11:24 p.m. UTC | #7
On 19/12/2020 00:39, Laurent Pinchart wrote:
> Hi Daniel,
> 
> On Fri, Dec 18, 2020 at 11:57:54PM +0000, Daniel Scally wrote:
>> Hi Laurent - thanks for the comments
>>
>> On 18/12/2020 16:53, Laurent Pinchart wrote:
>>>> +static void cio2_bridge_init_property_names(struct cio2_sensor *sensor)
>>>> +{
>>>> +	strscpy(sensor->prop_names.clock_frequency, "clock-frequency",
>>>> +		sizeof(sensor->prop_names.clock_frequency));
>>>> +	strscpy(sensor->prop_names.rotation, "rotation",
>>>> +		sizeof(sensor->prop_names.rotation));
>>>> +	strscpy(sensor->prop_names.bus_type, "bus-type",
>>>> +		sizeof(sensor->prop_names.bus_type));
>>>> +	strscpy(sensor->prop_names.data_lanes, "data-lanes",
>>>> +		sizeof(sensor->prop_names.data_lanes));
>>>> +	strscpy(sensor->prop_names.remote_endpoint, "remote-endpoint",
>>>> +		sizeof(sensor->prop_names.remote_endpoint));
>>>> +	strscpy(sensor->prop_names.link_frequencies, "link-frequencies",
>>>> +		sizeof(sensor->prop_names.link_frequencies));
>>>
>>> Just curious, was there anything not working correctly with the proposal
>>> I made ?
>>>
>>> static const struct cio2_property_names prop_names = {
>>> 	.clock_frequency = "clock-frequency",
>>> 	.rotation = "rotation",
>>> 	.bus_type = "bus-type",
>>> 	.data_lanes = "data-lanes",
>>> 	.remote_endpoint = "remote-endpoint",
>>> };
>>>
>>> static void cio2_bridge_init_property_names(struct cio2_sensor *sensor)
>>> {
>>> 	sensor->prop_names = prop_names;
>>> }
>>>
>>> It generates a warning when the string is too long for the field size,
>>> which should help catching issues at compilation time.
>>
>> Yes, though I don't know how much of a real-world problem it would have
>> been - if you recall we have the issue that the device grabs a reference
>> to the software_nodes (after we stopped delaying until after the
>> i2c_client is available), which means we can't safely free the
>> cio2_bridge struct on module unload. That also means we can't rely on
>> those pointers to string literals existing, because if the ipu3-cio2
>> module gets unloaded they'll be gone.
> 
> But the strings above are not stored as literals in .rodata, they're
> copied in prop_names (itself in .rodata), which is then copied to
> sensor->prop_names.

Yeah, my bad; I also had changed the struct definition to:

struct cio2_property_names {
	char *clock_frequency;
	...
};

And that behaves differently - apologies. I'll change to your proposal.
Daniel Scally Dec. 19, 2020, 11:48 p.m. UTC | #8
On 19/12/2020 18:52, Andy Shevchenko wrote:
> On Sat, Dec 19, 2020 at 2:25 AM Daniel Scally <djrscally@gmail.com> wrote:
>> On 18/12/2020 21:17, Andy Shevchenko wrote:
>>> On Thu, Dec 17, 2020 at 11:43:37PM +0000, Daniel Scally wrote:
> 
> ...
> 
>>>> +    sensor->ep_properties[0] = PROPERTY_ENTRY_U32(sensor->prop_names.bus_type, 4);
>>>
>>> Does 4 has any meaning that can be described by #define ?
>>
>> It's V4L2_FWNODE_BUS_TYPE_CSI2_DPHY:
>>
>> https://elixir.bootlin.com/linux/latest/source/drivers/media/v4l2-core/v4l2-fwnode.c#L36
>>
>> That enum's not in an accessible header, but I can define it in this
>> module's header
> 
> Maybe you can do a preparatory patch to make it visible to v4l2
> drivers? (Like moving to one of v4l2 headers)

Sure ok, guess media/v4l2-fwnode.h makes the most sense.

> ...
> 
>>>> +                    if (bridge->n_sensors >= CIO2_NUM_PORTS) {
>>>> +                            dev_warn(&cio2->dev, "Exceeded available CIO2 ports\n");
>>>
>>>> +                            /* overflow i so outer loop ceases */
>>>> +                            i = ARRAY_SIZE(cio2_supported_sensors);
>>>> +                            break;
>>>
>>> Why not to create a new label below and assign ret here with probably comment
>>> why it's not an error?
>>
>> Sure, I can do that, but since it wouldn't need any cleanup I could also
>> just return 0 here as Laurent suggest (but with a comment explaining why
>> that's ok as you say) - do you have a preference?
> 
> While it's a good suggestion it will bring a bit of inconsistency into
> approach. Everywhere else in the function you are using the goto
> approach.
> So yes, I have a preference.

No problem

>>>> +                    }
> 
> ...
> 
>>>> +                    ret = cio2_bridge_read_acpi_buffer(adev, "SSDB",
>>>> +                                                       &sensor->ssdb,
>>>> +                                                       sizeof(sensor->ssdb));
>>>> +                    if (ret < 0)
>>>
>>> if (ret) (because positive case can be returned just by next conditional).
>>
>> cio2_bridge_read_acpi_buffer() returns the buffer length on success at
>> the moment, but I can change it to return 0 and have this be if (ret)
> 
> Please correct this somehow, because the next failure returns it
> instead of error...

Ah! Good spot - thank you. I will fix that yes.

>>>> +                            goto err_put_adev;
>>>> +
>>>> +                    if (sensor->ssdb.lanes > 4) {
>>>> +                            dev_err(&adev->dev,
>>>> +                                    "Number of lanes in SSDB is invalid\n");
> 
> ...I'm even thinking that you have to assign ret here to something meaningful.

Yeah I agree, I will do this too.

>>>> +                            goto err_put_adev;
>>>> +                    }
>
Sakari Ailus Dec. 21, 2020, 10:21 a.m. UTC | #9
Hi Daniel, Andy,

On Sat, Dec 19, 2020 at 11:48:51PM +0000, Daniel Scally wrote:
> On 19/12/2020 18:52, Andy Shevchenko wrote:
> > On Sat, Dec 19, 2020 at 2:25 AM Daniel Scally <djrscally@gmail.com> wrote:
> >> On 18/12/2020 21:17, Andy Shevchenko wrote:
> >>> On Thu, Dec 17, 2020 at 11:43:37PM +0000, Daniel Scally wrote:
> > 
> > ...
> > 
> >>>> +    sensor->ep_properties[0] = PROPERTY_ENTRY_U32(sensor->prop_names.bus_type, 4);
> >>>
> >>> Does 4 has any meaning that can be described by #define ?
> >>
> >> It's V4L2_FWNODE_BUS_TYPE_CSI2_DPHY:
> >>
> >> https://elixir.bootlin.com/linux/latest/source/drivers/media/v4l2-core/v4l2-fwnode.c#L36
> >>
> >> That enum's not in an accessible header, but I can define it in this
> >> module's header
> > 
> > Maybe you can do a preparatory patch to make it visible to v4l2
> > drivers? (Like moving to one of v4l2 headers)
> 
> Sure ok, guess media/v4l2-fwnode.h makes the most sense.

Yes, please.

> 
> > ...
> > 
> >>>> +                    if (bridge->n_sensors >= CIO2_NUM_PORTS) {
> >>>> +                            dev_warn(&cio2->dev, "Exceeded available CIO2 ports\n");
> >>>
> >>>> +                            /* overflow i so outer loop ceases */
> >>>> +                            i = ARRAY_SIZE(cio2_supported_sensors);
> >>>> +                            break;
> >>>
> >>> Why not to create a new label below and assign ret here with probably comment
> >>> why it's not an error?
> >>
> >> Sure, I can do that, but since it wouldn't need any cleanup I could also
> >> just return 0 here as Laurent suggest (but with a comment explaining why
> >> that's ok as you say) - do you have a preference?
> > 
> > While it's a good suggestion it will bring a bit of inconsistency into
> > approach. Everywhere else in the function you are using the goto
> > approach.
> > So yes, I have a preference.
> 
> No problem

Laurent also commented on the return code.

I might just handle this as an error. The earlier ports are fine, but
there's also a problem with the data here. It'd be easier to spot that this
way, and we can change this in the future if need be.
Daniel Scally Dec. 21, 2020, 10:52 a.m. UTC | #10
On 21/12/2020 10:21, Sakari Ailus wrote:
> Hi Daniel, Andy,
>
> On Sat, Dec 19, 2020 at 11:48:51PM +0000, Daniel Scally wrote:
>> On 19/12/2020 18:52, Andy Shevchenko wrote:
>>> On Sat, Dec 19, 2020 at 2:25 AM Daniel Scally <djrscally@gmail.com> wrote:
>>>> On 18/12/2020 21:17, Andy Shevchenko wrote:
>>>>> On Thu, Dec 17, 2020 at 11:43:37PM +0000, Daniel Scally wrote:
>>> ...
>>>
>>>>>> +    sensor->ep_properties[0] = PROPERTY_ENTRY_U32(sensor->prop_names.bus_type, 4);
>>>>> Does 4 has any meaning that can be described by #define ?
>>>> It's V4L2_FWNODE_BUS_TYPE_CSI2_DPHY:
>>>>
>>>> https://elixir.bootlin.com/linux/latest/source/drivers/media/v4l2-core/v4l2-fwnode.c#L36
>>>>
>>>> That enum's not in an accessible header, but I can define it in this
>>>> module's header
>>> Maybe you can do a preparatory patch to make it visible to v4l2
>>> drivers? (Like moving to one of v4l2 headers)
>> Sure ok, guess media/v4l2-fwnode.h makes the most sense.
> Yes, please.
Done for the next version
>
>>> ...
>>>
>>>>>> +                    if (bridge->n_sensors >= CIO2_NUM_PORTS) {
>>>>>> +                            dev_warn(&cio2->dev, "Exceeded available CIO2 ports\n");
>>>>>> +                            /* overflow i so outer loop ceases */
>>>>>> +                            i = ARRAY_SIZE(cio2_supported_sensors);
>>>>>> +                            break;
>>>>> Why not to create a new label below and assign ret here with probably comment
>>>>> why it's not an error?
>>>> Sure, I can do that, but since it wouldn't need any cleanup I could also
>>>> just return 0 here as Laurent suggest (but with a comment explaining why
>>>> that's ok as you say) - do you have a preference?
>>> While it's a good suggestion it will bring a bit of inconsistency into
>>> approach. Everywhere else in the function you are using the goto
>>> approach.
>>> So yes, I have a preference.
>> No problem
> Laurent also commented on the return code.
>
> I might just handle this as an error. The earlier ports are fine, but
> there's also a problem with the data here. It'd be easier to spot that this
> way, and we can change this in the future if need be.


You mean just raise an error with dev_err()? Or fail the probe and
unwind the 4 sensors that were already connected successfully? I'm fine
with that if so - we have no in scope devices where that will be a
problem at the moment.
Sakari Ailus Dec. 21, 2020, 10:57 a.m. UTC | #11
On Mon, Dec 21, 2020 at 10:52:52AM +0000, Daniel Scally wrote:
> 
> On 21/12/2020 10:21, Sakari Ailus wrote:
> > Hi Daniel, Andy,
> >
> > On Sat, Dec 19, 2020 at 11:48:51PM +0000, Daniel Scally wrote:
> >> On 19/12/2020 18:52, Andy Shevchenko wrote:
> >>> On Sat, Dec 19, 2020 at 2:25 AM Daniel Scally <djrscally@gmail.com> wrote:
> >>>> On 18/12/2020 21:17, Andy Shevchenko wrote:
> >>>>> On Thu, Dec 17, 2020 at 11:43:37PM +0000, Daniel Scally wrote:
> >>> ...
> >>>
> >>>>>> +    sensor->ep_properties[0] = PROPERTY_ENTRY_U32(sensor->prop_names.bus_type, 4);
> >>>>> Does 4 has any meaning that can be described by #define ?
> >>>> It's V4L2_FWNODE_BUS_TYPE_CSI2_DPHY:
> >>>>
> >>>> https://elixir.bootlin.com/linux/latest/source/drivers/media/v4l2-core/v4l2-fwnode.c#L36
> >>>>
> >>>> That enum's not in an accessible header, but I can define it in this
> >>>> module's header
> >>> Maybe you can do a preparatory patch to make it visible to v4l2
> >>> drivers? (Like moving to one of v4l2 headers)
> >> Sure ok, guess media/v4l2-fwnode.h makes the most sense.
> > Yes, please.
> Done for the next version
> >
> >>> ...
> >>>
> >>>>>> +                    if (bridge->n_sensors >= CIO2_NUM_PORTS) {
> >>>>>> +                            dev_warn(&cio2->dev, "Exceeded available CIO2 ports\n");
> >>>>>> +                            /* overflow i so outer loop ceases */
> >>>>>> +                            i = ARRAY_SIZE(cio2_supported_sensors);
> >>>>>> +                            break;
> >>>>> Why not to create a new label below and assign ret here with probably comment
> >>>>> why it's not an error?
> >>>> Sure, I can do that, but since it wouldn't need any cleanup I could also
> >>>> just return 0 here as Laurent suggest (but with a comment explaining why
> >>>> that's ok as you say) - do you have a preference?
> >>> While it's a good suggestion it will bring a bit of inconsistency into
> >>> approach. Everywhere else in the function you are using the goto
> >>> approach.
> >>> So yes, I have a preference.
> >> No problem
> > Laurent also commented on the return code.
> >
> > I might just handle this as an error. The earlier ports are fine, but
> > there's also a problem with the data here. It'd be easier to spot that this
> > way, and we can change this in the future if need be.
> 
> 
> You mean just raise an error with dev_err()? Or fail the probe and
> unwind the 4 sensors that were already connected successfully? I'm fine

Both.

> with that if so - we have no in scope devices where that will be a
> problem at the moment.

I guess there will be quite a few additional things to address before
getting anything with four sensors working.
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 16b544624577..e7784b4bc8ea 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8943,6 +8943,7 @@  INTEL IPU3 CSI-2 CIO2 DRIVER
 M:	Yong Zhi <yong.zhi@intel.com>
 M:	Sakari Ailus <sakari.ailus@linux.intel.com>
 M:	Bingbu Cao <bingbu.cao@intel.com>
+M:	Dan Scally <djrscally@gmail.com>
 R:	Tianshu Qiu <tian.shu.qiu@intel.com>
 L:	linux-media@vger.kernel.org
 S:	Maintained
diff --git a/drivers/media/pci/intel/ipu3/Kconfig b/drivers/media/pci/intel/ipu3/Kconfig
index 82d7f17e6a02..dcf5c4b74673 100644
--- a/drivers/media/pci/intel/ipu3/Kconfig
+++ b/drivers/media/pci/intel/ipu3/Kconfig
@@ -16,3 +16,21 @@  config VIDEO_IPU3_CIO2
 	  Say Y or M here if you have a Skylake/Kaby Lake SoC with MIPI CSI-2
 	  connected camera.
 	  The module will be called ipu3-cio2.
+
+config CIO2_BRIDGE
+	bool "IPU3 CIO2 Sensors Bridge"
+	depends on VIDEO_IPU3_CIO2
+	help
+	  This extension provides an API for the ipu3-cio2 driver to create
+	  connections to cameras that are hidden in SSDB buffer in ACPI. It
+	  can be used to enable support for cameras in detachable / hybrid
+	  devices that ship with Windows.
+
+	  Say Y here if your device is a detachable / hybrid laptop that comes
+	  with Windows installed by the OEM, for example:
+
+		- Microsoft Surface models (except Surface Pro 3)
+		- The Lenovo Miix line (for example the 510, 520, 710 and 720)
+		- Dell 7285
+
+	  If in doubt, say N here.
diff --git a/drivers/media/pci/intel/ipu3/Makefile b/drivers/media/pci/intel/ipu3/Makefile
index 429d516452e4..933777e6ea8a 100644
--- a/drivers/media/pci/intel/ipu3/Makefile
+++ b/drivers/media/pci/intel/ipu3/Makefile
@@ -2,3 +2,4 @@ 
 obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2.o
 
 ipu3-cio2-y += ipu3-cio2-main.o
+ipu3-cio2-$(CONFIG_CIO2_BRIDGE) += cio2-bridge.o
diff --git a/drivers/media/pci/intel/ipu3/cio2-bridge.c b/drivers/media/pci/intel/ipu3/cio2-bridge.c
new file mode 100644
index 000000000000..3f0e2d7eab20
--- /dev/null
+++ b/drivers/media/pci/intel/ipu3/cio2-bridge.c
@@ -0,0 +1,274 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dan Scally <djrscally@gmail.com> */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/pci.h>
+#include <linux/property.h>
+
+#include "cio2-bridge.h"
+
+/*
+ * Extend this array with ACPI Hardware ID's of devices known to be working
+ * plus the number of link-frequencies expected by their drivers, along with
+ * the frequency values in hertz. This is somewhat opportunistic way of adding
+ * support for this for now in the hopes of a better source for the information
+ * (possibly some encoded value in the SSDB buffer that we're unaware of)
+ * becoming apparent in the future.
+ *
+ * Do not add an entry for a sensor that is not actually supported.
+ */
+static const struct cio2_sensor_config cio2_supported_sensors[] = {
+	CIO2_SENSOR_CONFIG("INT33BE", 0),
+	CIO2_SENSOR_CONFIG("OVTI2680", 0),
+};
+
+static int cio2_bridge_read_acpi_buffer(struct acpi_device *adev, char *id,
+					void *data, u32 size)
+{
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *obj;
+	acpi_status status;
+	int ret;
+
+	status = acpi_evaluate_object(adev->handle, id, NULL, &buffer);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	obj = buffer.pointer;
+	if (!obj) {
+		dev_err(&adev->dev, "Couldn't locate ACPI buffer\n");
+		return -ENODEV;
+	}
+
+	if (obj->type != ACPI_TYPE_BUFFER) {
+		dev_err(&adev->dev, "Not an ACPI buffer\n");
+		ret = -ENODEV;
+		goto out_free_buff;
+	}
+
+	if (obj->buffer.length > size) {
+		dev_err(&adev->dev, "Given buffer is too small\n");
+		ret = -EINVAL;
+		goto out_free_buff;
+	}
+
+	memcpy(data, obj->buffer.pointer, obj->buffer.length);
+	ret = obj->buffer.length;
+
+out_free_buff:
+	kfree(buffer.pointer);
+	return ret;
+}
+
+static void cio2_bridge_init_property_names(struct cio2_sensor *sensor)
+{
+	strscpy(sensor->prop_names.clock_frequency, "clock-frequency",
+		sizeof(sensor->prop_names.clock_frequency));
+	strscpy(sensor->prop_names.rotation, "rotation",
+		sizeof(sensor->prop_names.rotation));
+	strscpy(sensor->prop_names.bus_type, "bus-type",
+		sizeof(sensor->prop_names.bus_type));
+	strscpy(sensor->prop_names.data_lanes, "data-lanes",
+		sizeof(sensor->prop_names.data_lanes));
+	strscpy(sensor->prop_names.remote_endpoint, "remote-endpoint",
+		sizeof(sensor->prop_names.remote_endpoint));
+	strscpy(sensor->prop_names.link_frequencies, "link-frequencies",
+		sizeof(sensor->prop_names.link_frequencies));
+}
+
+static void cio2_bridge_create_fwnode_properties(struct cio2_sensor *sensor,
+						 const struct cio2_sensor_config *cfg)
+{
+	unsigned int i;
+
+	cio2_bridge_init_property_names(sensor);
+
+	for (i = 0; i < 4; i++)
+		sensor->data_lanes[i] = i + 1;
+
+	sensor->local_ref[0].node = &sensor->swnodes[SWNODE_CIO2_ENDPOINT];
+	sensor->remote_ref[0].node = &sensor->swnodes[SWNODE_SENSOR_ENDPOINT];
+
+	sensor->dev_properties[0] = PROPERTY_ENTRY_U32(sensor->prop_names.clock_frequency,
+						       sensor->ssdb.mclkspeed);
+	sensor->dev_properties[1] = PROPERTY_ENTRY_U8(sensor->prop_names.rotation,
+						      sensor->ssdb.degree);
+
+	sensor->ep_properties[0] = PROPERTY_ENTRY_U32(sensor->prop_names.bus_type, 4);
+	sensor->ep_properties[1] = PROPERTY_ENTRY_U32_ARRAY_LEN(sensor->prop_names.data_lanes,
+								sensor->data_lanes,
+								sensor->ssdb.lanes);
+	sensor->ep_properties[2] = PROPERTY_ENTRY_REF_ARRAY(sensor->prop_names.remote_endpoint,
+							    sensor->local_ref);
+
+	if (cfg->nr_link_freqs > 0)
+		sensor->ep_properties[3] = PROPERTY_ENTRY_U64_ARRAY_LEN(
+						sensor->prop_names.link_frequencies,
+						cfg->link_freqs,
+						cfg->nr_link_freqs);
+
+	sensor->cio2_properties[0] = PROPERTY_ENTRY_U32_ARRAY_LEN(sensor->prop_names.data_lanes,
+								  sensor->data_lanes,
+								  sensor->ssdb.lanes);
+	sensor->cio2_properties[1] = PROPERTY_ENTRY_REF_ARRAY(sensor->prop_names.remote_endpoint,
+							      sensor->remote_ref);
+}
+
+static void cio2_bridge_init_swnode_names(struct cio2_sensor *sensor)
+{
+	snprintf(sensor->node_names.remote_port, 7, "port@%u", sensor->ssdb.link);
+	strscpy(sensor->node_names.port, "port@0", sizeof(sensor->node_names.port));
+	strscpy(sensor->node_names.endpoint, "endpoint@0", sizeof(sensor->node_names.endpoint));
+}
+
+static void cio2_bridge_create_connection_swnodes(struct cio2_bridge *bridge,
+						  struct cio2_sensor *sensor)
+{
+	struct software_node *nodes = sensor->swnodes;
+
+	cio2_bridge_init_swnode_names(sensor);
+
+	nodes[SWNODE_SENSOR_HID] = NODE_SENSOR(sensor->name,
+					       sensor->dev_properties);
+	nodes[SWNODE_SENSOR_PORT] = NODE_PORT(sensor->node_names.port,
+					      &nodes[SWNODE_SENSOR_HID]);
+	nodes[SWNODE_SENSOR_ENDPOINT] = NODE_ENDPOINT(sensor->node_names.endpoint,
+						      &nodes[SWNODE_SENSOR_PORT],
+						      sensor->ep_properties);
+	nodes[SWNODE_CIO2_PORT] = NODE_PORT(sensor->node_names.remote_port,
+					    &bridge->cio2_hid_node);
+	nodes[SWNODE_CIO2_ENDPOINT] = NODE_ENDPOINT(sensor->node_names.endpoint,
+						    &nodes[SWNODE_CIO2_PORT],
+						    sensor->cio2_properties);
+}
+
+static void cio2_bridge_unregister_sensors(struct cio2_bridge *bridge)
+{
+	struct cio2_sensor *sensor;
+	unsigned int i;
+
+	for (i = 0; i < bridge->n_sensors; i++) {
+		sensor = &bridge->sensors[i];
+		software_node_unregister_nodes(sensor->swnodes);
+		acpi_dev_put(sensor->adev);
+	}
+}
+
+static int cio2_bridge_connect_sensors(struct cio2_bridge *bridge,
+				       struct pci_dev *cio2)
+{
+	struct fwnode_handle *fwnode;
+	struct cio2_sensor *sensor;
+	struct acpi_device *adev;
+	unsigned int i;
+	int ret = 0;
+
+	for (i = 0; i < ARRAY_SIZE(cio2_supported_sensors); i++) {
+		const struct cio2_sensor_config *cfg = &cio2_supported_sensors[i];
+
+		for_each_acpi_dev_match(adev, cfg->hid, NULL, -1) {
+			if (bridge->n_sensors >= CIO2_NUM_PORTS) {
+				dev_warn(&cio2->dev, "Exceeded available CIO2 ports\n");
+				/* overflow i so outer loop ceases */
+				i = ARRAY_SIZE(cio2_supported_sensors);
+				break;
+			}
+
+			if (!adev->status.enabled)
+				continue;
+
+			sensor = &bridge->sensors[bridge->n_sensors];
+			sensor->adev = adev;
+			strscpy(sensor->name, cfg->hid, sizeof(sensor->name));
+
+			ret = cio2_bridge_read_acpi_buffer(adev, "SSDB",
+							   &sensor->ssdb,
+							   sizeof(sensor->ssdb));
+			if (ret < 0)
+				goto err_put_adev;
+
+			if (sensor->ssdb.lanes > 4) {
+				dev_err(&adev->dev,
+					"Number of lanes in SSDB is invalid\n");
+				goto err_put_adev;
+			}
+
+			cio2_bridge_create_fwnode_properties(sensor, cfg);
+			cio2_bridge_create_connection_swnodes(bridge, sensor);
+
+			ret = software_node_register_nodes(sensor->swnodes);
+			if (ret)
+				goto err_put_adev;
+
+			fwnode = software_node_fwnode(&sensor->swnodes[SWNODE_SENSOR_HID]);
+			if (!fwnode) {
+				ret = -ENODEV;
+				goto err_free_swnodes;
+			}
+
+			adev->fwnode.secondary = fwnode;
+
+			dev_info(&cio2->dev, "Found supported sensor %s\n",
+				 acpi_dev_name(adev));
+
+			bridge->n_sensors++;
+		}
+	}
+
+	return ret;
+
+err_free_swnodes:
+	software_node_unregister_nodes(sensor->swnodes);
+err_put_adev:
+	acpi_dev_put(sensor->adev);
+
+	return ret;
+}
+
+int cio2_bridge_init(struct pci_dev *cio2)
+{
+	struct device *dev = &cio2->dev;
+	struct fwnode_handle *fwnode;
+	struct cio2_bridge *bridge;
+	int ret;
+
+	bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
+	if (!bridge)
+		return -ENOMEM;
+
+	strscpy(bridge->cio2_node_name, CIO2_HID, sizeof(bridge->cio2_node_name));
+	bridge->cio2_hid_node.name = bridge->cio2_node_name;
+
+	ret = software_node_register(&bridge->cio2_hid_node);
+	if (ret < 0) {
+		dev_err(dev, "Failed to register the CIO2 HID node\n");
+		goto err_free_bridge;
+	}
+
+	ret = cio2_bridge_connect_sensors(bridge, cio2);
+	if (ret || bridge->n_sensors == 0)
+		goto err_unregister_cio2;
+
+	dev_info(dev, "Connected %d cameras\n", bridge->n_sensors);
+
+	fwnode = software_node_fwnode(&bridge->cio2_hid_node);
+	if (!fwnode) {
+		dev_err(dev, "Error getting fwnode from cio2 software_node\n");
+		ret = -ENODEV;
+		goto err_unregister_sensors;
+	}
+
+	set_secondary_fwnode(dev, fwnode);
+
+	return 0;
+
+err_unregister_sensors:
+	cio2_bridge_unregister_sensors(bridge);
+err_unregister_cio2:
+	software_node_unregister(&bridge->cio2_hid_node);
+err_free_bridge:
+	kfree(bridge);
+
+	return ret;
+}
diff --git a/drivers/media/pci/intel/ipu3/cio2-bridge.h b/drivers/media/pci/intel/ipu3/cio2-bridge.h
new file mode 100644
index 000000000000..f89a8e33f82c
--- /dev/null
+++ b/drivers/media/pci/intel/ipu3/cio2-bridge.h
@@ -0,0 +1,122 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Author: Dan Scally <djrscally@gmail.com> */
+#ifndef __CIO2_BRIDGE_H
+#define __CIO2_BRIDGE_H
+
+#include <linux/property.h>
+
+#define CIO2_HID				"INT343E"
+#define CIO2_NUM_PORTS				4
+#define MAX_NUM_LINK_FREQS			3
+
+#define CIO2_SENSOR_CONFIG(_HID, _NR, ...)	\
+	{					\
+		.hid = _HID,			\
+		.nr_link_freqs = _NR,		\
+		.link_freqs = { __VA_ARGS__ }	\
+	}
+
+#define NODE_SENSOR(_HID, _PROPS)		\
+	((const struct software_node) {		\
+		.name = _HID,			\
+		.properties = _PROPS,		\
+	})
+
+#define NODE_PORT(_PORT, _SENSOR_NODE)		\
+	((const struct software_node) {		\
+		_PORT,				\
+		_SENSOR_NODE,			\
+	})
+
+#define NODE_ENDPOINT(_EP, _PORT, _PROPS)	\
+	((const struct software_node) {		\
+		_EP,				\
+		_PORT,				\
+		_PROPS,				\
+	})
+
+enum cio2_sensor_swnodes {
+	SWNODE_SENSOR_HID,
+	SWNODE_SENSOR_PORT,
+	SWNODE_SENSOR_ENDPOINT,
+	SWNODE_CIO2_PORT,
+	SWNODE_CIO2_ENDPOINT,
+	NR_OF_SENSOR_SWNODES
+};
+
+/* Data representation as it is in ACPI SSDB buffer */
+struct cio2_sensor_ssdb {
+	u8 version;				/* 0000 */
+	u8 sku;					/* 0001 */
+	u8 guid_csi2[16];			/* 0002 */
+	u8 devfunction;				/* 0003 */
+	u8 bus;					/* 0004 */
+	u32 dphylinkenfuses;			/* 0005 */
+	u32 clockdiv;				/* 0009 */
+	u8 link;				/* 0013 */
+	u8 lanes;				/* 0014 */
+	u32 csiparams[10];			/* 0015 */
+	u32 maxlanespeed;			/* 0019 */
+	u8 sensorcalibfileidx;			/* 0023 */
+	u8 sensorcalibfileidxInMBZ[3];		/* 0024 */
+	u8 romtype;				/* 0025 */
+	u8 vcmtype;				/* 0026 */
+	u8 platforminfo;			/* 0027 */
+	u8 platformsubinfo;
+	u8 flash;
+	u8 privacyled;
+	u8 degree;
+	u8 mipilinkdefined;
+	u32 mclkspeed;
+	u8 controllogicid;
+	u8 reserved1[3];
+	u8 mclkport;
+	u8 reserved2[13];
+} __packed;
+
+struct cio2_property_names {
+	char clock_frequency[16];
+	char rotation[9];
+	char bus_type[9];
+	char data_lanes[11];
+	char remote_endpoint[16];
+	char link_frequencies[17];
+};
+
+struct cio2_node_names {
+	char port[7];
+	char endpoint[11];
+	char remote_port[7];
+};
+
+struct cio2_sensor_config {
+	const char *hid;
+	const u8 nr_link_freqs;
+	const u64 link_freqs[MAX_NUM_LINK_FREQS];
+};
+
+struct cio2_sensor {
+	char name[ACPI_ID_LEN];
+	struct acpi_device *adev;
+
+	struct software_node swnodes[6];
+	struct cio2_node_names node_names;
+
+	u32 data_lanes[4];
+	struct cio2_sensor_ssdb ssdb;
+	struct cio2_property_names prop_names;
+	struct property_entry ep_properties[5];
+	struct property_entry dev_properties[3];
+	struct property_entry cio2_properties[3];
+	struct software_node_ref_args local_ref[1];
+	struct software_node_ref_args remote_ref[1];
+};
+
+struct cio2_bridge {
+	char cio2_node_name[ACPI_ID_LEN];
+	struct software_node cio2_hid_node;
+	unsigned int n_sensors;
+	struct cio2_sensor sensors[CIO2_NUM_PORTS];
+};
+
+#endif
diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
index 36e354ecf71e..68ff28abc6a3 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
@@ -1702,11 +1702,28 @@  static void cio2_queues_exit(struct cio2_device *cio2)
 		cio2_queue_exit(cio2, &cio2->queue[i]);
 }
 
+static bool cio2_check_fwnode_graph(struct fwnode_handle *fwnode)
+{
+	struct fwnode_handle *endpoint;
+
+	if (IS_ERR_OR_NULL(fwnode))
+		return false;
+
+	endpoint = fwnode_graph_get_next_endpoint(fwnode, NULL);
+	if (endpoint) {
+		fwnode_handle_put(endpoint);
+		return true;
+	}
+
+	return cio2_check_fwnode_graph(fwnode->secondary);
+}
+
 /**************** PCI interface ****************/
 
 static int cio2_pci_probe(struct pci_dev *pci_dev,
 			  const struct pci_device_id *id)
 {
+	struct fwnode_handle *fwnode = dev_fwnode(&pci_dev->dev);
 	struct cio2_device *cio2;
 	int r;
 
@@ -1715,6 +1732,23 @@  static int cio2_pci_probe(struct pci_dev *pci_dev,
 		return -ENOMEM;
 	cio2->pci_dev = pci_dev;
 
+	/*
+	 * On some platforms no connections to sensors are defined in firmware,
+	 * if the device has no endpoints then we can try to build those as
+	 * software_nodes parsed from SSDB.
+	 */
+	if (!cio2_check_fwnode_graph(fwnode)) {
+		if (fwnode && !IS_ERR_OR_NULL(fwnode->secondary)) {
+			dev_err(&pci_dev->dev,
+				"fwnode graph has no endpoints connected\n");
+			return -EINVAL;
+		}
+
+		r = cio2_bridge_init(pci_dev);
+		if (r)
+			return r;
+	}
+
 	r = pcim_enable_device(pci_dev);
 	if (r) {
 		dev_err(&pci_dev->dev, "failed to enable device (%d)\n", r);
diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2.h b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
index ccf0b85ae36f..520a27c9cdad 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2.h
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
@@ -437,4 +437,10 @@  static inline struct cio2_queue *vb2q_to_cio2_queue(struct vb2_queue *vq)
 	return container_of(vq, struct cio2_queue, vbq);
 }
 
+#if IS_ENABLED(CONFIG_CIO2_BRIDGE)
+int cio2_bridge_init(struct pci_dev *cio2);
+#else
+int cio2_bridge_init(struct pci_dev *cio2) { return 0; }
+#endif
+
 #endif