Hi Daniel,

Thanks for the update! This is starting to look really nice!

Please still see my comments below.

On Mon, Nov 30, 2020 at 01:31:24PM +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 <jorh...@linux.microsoft.com>
> Signed-off-by: Daniel Scally <djrsca...@gmail.com>
> ---
> Changes since RFC v3:
> 
>       - Removed almost all global variables, dynamically allocated
>       the cio2_bridge structure, plus a bunch of associated changes
>       like 
>       - Added a new function to ipu3-cio2-main.c to check for an 
>       existing fwnode_graph before calling cio2_bridge_init()
>       - Prefixed cio2_bridge_ to any variables and functions that
>       lacked it
>       - Assigned the new fwnode directly to the sensor's ACPI device
>       fwnode as secondary. This removes the requirement to delay until
>       the I2C devices are instantiated before ipu3-cio2 can probe, but
>       it has a side effect, which is that those devices then grab a ref
>       to the new software_node. This effectively prevents us from
>       unloading the driver, because we can't free the memory that they
>       live in whilst the device holds a reference to them. The work
>       around at the moment is to _not_ unregister the software_nodes
>       when ipu3-cio2 is unloaded; this becomes a one-time 'patch', that
>       is simply skipped if the module is reloaded.
>       - Moved the sensor's SSDB struct to be a member of cio2_sensor
>       - Replaced ints with unsigned ints where appropriate
>       - Iterated over all ACPI devices of a matching _HID rather than
>       just the first to ensure we handle a device with multiple sensors
>       of the same model.
> 
>  MAINTAINERS                                   |   1 +
>  drivers/media/pci/intel/ipu3/Kconfig          |  18 ++
>  drivers/media/pci/intel/ipu3/Makefile         |   1 +
>  drivers/media/pci/intel/ipu3/cio2-bridge.c    | 260 ++++++++++++++++++
>  drivers/media/pci/intel/ipu3/cio2-bridge.h    | 108 ++++++++
>  drivers/media/pci/intel/ipu3/ipu3-cio2-main.c |  27 ++
>  drivers/media/pci/intel/ipu3/ipu3-cio2.h      |   6 +
>  7 files changed, 421 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 9702b886d6a4..188559a0a610 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -8927,6 +8927,7 @@ INTEL IPU3 CSI-2 CIO2 DRIVER
>  M:   Yong Zhi <yong....@intel.com>
>  M:   Sakari Ailus <sakari.ai...@linux.intel.com>
>  M:   Bingbu Cao <bingbu....@intel.com>
> +M:   Dan Scally <djrsca...@gmail.com>
>  R:   Tianshu Qiu <tian.shu....@intel.com>
>  L:   linux-me...@vger.kernel.org
>  S:   Maintained
> diff --git a/drivers/media/pci/intel/ipu3/Kconfig 
> b/drivers/media/pci/intel/ipu3/Kconfig
> index 82d7f17e6a02..2b3350d042be 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..fd3f8ba07274
> --- /dev/null
> +++ b/drivers/media/pci/intel/ipu3/cio2-bridge.c
> @@ -0,0 +1,260 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Author: Dan Scally <djrsca...@gmail.com> */
> +#include <linux/acpi.h>
> +#include <linux/device.h>
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/property.h>
> +#include <media/v4l2-subdev.h>
> +
> +#include "cio2-bridge.h"
> +
> +/*
> + * Extend this array with ACPI Hardware ID's of devices known to be working.
> + * Do not add a HID for a sensor that is not actually supported.
> + */
> +static const char * const cio2_supported_devices[] = {
> +     "INT33BE",
> +     "OVTI2680",

I guess we don't have the known-good frequencies for the CSI-2 bus in
firmware?

One option would be to put there what the drivers currently use. This
assumes the support for these devices is, well, somewhat opportunistic but
I guess there's no way around that right now at least.

As the systems are laptops, they're likely somewhat less prone to EMI
issues to begin with than mobile phones anyway.

> +};
> +
> +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)
> +{
> +     strcpy(sensor->prop_names.clock_frequency, "clock-frequency");
> +     strcpy(sensor->prop_names.rotation, "rotation");
> +     strcpy(sensor->prop_names.bus_type, "bus-type");
> +     strcpy(sensor->prop_names.data_lanes, "data-lanes");
> +     strcpy(sensor->prop_names.remote_endpoint, "remote-endpoint");

Please use the actual field size instead with strncpy / strscpy.

> +}
> +
> +static void cio2_bridge_create_fwnode_properties(struct cio2_sensor *sensor)
> +{
> +     unsigned int i;
> +
> +     cio2_bridge_init_property_names(sensor);
> +
> +     for (i = 0; i < 4; i++)
> +             sensor->data_lanes[i] = i + 1;
> +
> +     /*
> +      * Can't use PROPERTY_ENTRY_REF because it creates a new variable to
> +      * point to, which doesn't survive the function.
> +      */
> +     sensor->local_ref[0] = (struct software_node_ref_args){
> +             .node = &sensor->swnodes[SWNODE_CIO2_ENDPOINT]
> +             };

I guess this line should be unindented by one tab stop. Same for the
similar case below.

> +     sensor->remote_ref[0] = (struct software_node_ref_args){
> +             .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, 5);
> +     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);
> +
> +     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, 6, "port%u", 
> sensor->ssdb.link);
> +     strcpy(sensor->node_names.port, "port0");
> +     strcpy(sensor->node_names.endpoint, "endpoint0");

Please use the actual size of the field, and strncpy / strscpy.

> +}
> +
> +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 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_devices); i++) {
> +             const char *this_device = cio2_supported_devices[i];
> +
> +             for_each_acpi_dev_match(adev, this_device, NULL, -1) {
> +                     if (!adev || !(adev->status.present && 
> adev->status.enabled))
> +                             continue;
> +
> +                     sensor = &bridge->sensors[bridge->n_sensors];
> +                     sensor->adev = adev;
> +                     strscpy(sensor->name, this_device, 
> 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);
> +                     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(&bridge->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 = (const struct software_node){ 
> bridge->cio2_node_name };
> +     bridge->cio2 = pci_dev_get(cio2);
> +
> +     ret = software_node_register(&bridge->cio2_hid_node);
> +     if (ret < 0) {
> +             dev_err(dev, "Failed to register the CIO2 HID node\n");
> +             goto err_put_cio2;
> +     }
> +
> +     ret = cio2_bridge_connect_sensors(bridge);
> +     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_put_cio2:
> +     pci_dev_put(bridge->cio2);
> +
> +     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..96f5c8a12be0
> --- /dev/null
> +++ b/drivers/media/pci/intel/ipu3/cio2-bridge.h
> @@ -0,0 +1,108 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Author: Dan Scally <djrsca...@gmail.com> */
> +#ifndef __CIO2_BRIDGE_H
> +#define __CIO2_BRIDGE_H
> +
> +#include <linux/property.h>
> +
> +#define CIO2_HID                             "INT343E"
> +#define CIO2_NUM_PORTS                         4
> +
> +#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;
> +     u8 sku;
> +     u8 guid_csi2[16];
> +     u8 devfunction;
> +     u8 bus;
> +     u32 dphylinkenfuses;
> +     u32 clockdiv;
> +     u8 link;
> +     u8 lanes;
> +     u32 csiparams[10];
> +     u32 maxlanespeed;
> +     u8 sensorcalibfileidx;
> +     u8 sensorcalibfileidxInMBZ[3];
> +     u8 romtype;
> +     u8 vcmtype;
> +     u8 platforminfo;
> +     u8 platformsubinfo;
> +     u8 flash;
> +     u8 privacyled;
> +     u8 degree;
> +     u8 mipilinkdefined;
> +     u32 mclkspeed;
> +     u8 controllogicid;
> +     u8 reserved1[3];
> +     u8 mclkport;
> +     u8 reserved2[13];
> +} __packed__;

This should be "__packed".

> +
> +struct cio2_property_names {
> +     char clock_frequency[16];
> +     char rotation[9];
> +     char bus_type[9];
> +     char data_lanes[11];
> +     char remote_endpoint[16];
> +};
> +
> +struct cio2_node_names {
> +     char port[6];
> +     char endpoint[10];
> +     char remote_port[6];
> +};
> +
> +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[4];
> +     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 {
> +     struct pci_dev *cio2;
> +     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..0d69b593e9f0 100644
> --- a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
> +++ b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
> @@ -1702,6 +1702,22 @@ 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,
> @@ -1715,6 +1731,17 @@ 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(dev_fwnode(&pci_dev->dev))) {
> +             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

-- 
Kind regards,

Sakari Ailus

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