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 in v3:
        - Rather than overwriting the device's primary fwnode, we now
        simply assign a secondary. Some of the preceding patches alter the
        existing driver code and v4l2 framework to allow for that.
        - Rather than reprobe() the sensor after connecting the devices in
        cio2-bridge we create the software_nodes right away. In this case,
        sensor drivers will have to defer probing until they detect that a
        fwnode graph is connecting them to the CIO2 device.
        - Error paths in connect_supported_devices() moved outside the
        loop
        - Replaced pr_*() with dev_*() throughout
        - Moved creation of software_node / property_entry arrays to stack
        - A lot of formatting changes.

 MAINTAINERS                                   |   1 +
 drivers/media/pci/intel/ipu3/Kconfig          |  18 +
 drivers/media/pci/intel/ipu3/Makefile         |   3 +-
 drivers/media/pci/intel/ipu3/cio2-bridge.c    | 327 ++++++++++++++++++
 drivers/media/pci/intel/ipu3/cio2-bridge.h    |  94 +++++
 drivers/media/pci/intel/ipu3/ipu3-cio2-main.c |  21 ++
 drivers/media/pci/intel/ipu3/ipu3-cio2.h      |   9 +
 7 files changed, 472 insertions(+), 1 deletion(-)
 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 5d768d5ad..4c9c646c7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8848,6 +8848,7 @@ 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 82d7f17e6..d14cbceae 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:
+
+               - Some Microsoft Surface models
+               - The Lenovo Miix line
+               - 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 b4e3266d9..933777e6e 100644
--- a/drivers/media/pci/intel/ipu3/Makefile
+++ b/drivers/media/pci/intel/ipu3/Makefile
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2.o
 
-ipu3-cio2-y += ipu3-cio2-main.o
\ No newline at end of file
+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 000000000..bbe072f04
--- /dev/null
+++ b/drivers/media/pci/intel/ipu3/cio2-bridge.c
@@ -0,0 +1,327 @@
+// SPDX-License-Identifier: GPL-2.0
+// Author: Dan Scally <djrsca...@gmail.com>
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/fwnode.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
+ */
+static const char * const supported_devices[] = {
+       "INT33BE",
+       "OVTI2680",
+};
+
+static struct software_node cio2_hid_node = { CIO2_HID };
+
+static struct cio2_bridge bridge;
+
+static const char * const port_names[] = {
+       "port0", "port1", "port2", "port3"
+};
+
+static const struct property_entry remote_endpoints[] = {
+       PROPERTY_ENTRY_REF("remote-endpoint", /* Sensor 0, Sensor Property */
+                          &bridge.sensors[0].swnodes[SWNODE_CIO2_ENDPOINT]),
+       PROPERTY_ENTRY_REF("remote-endpoint", /* Sensor 0, CIO2 Property */
+                          &bridge.sensors[0].swnodes[SWNODE_SENSOR_ENDPOINT]),
+       PROPERTY_ENTRY_REF("remote-endpoint",
+                          &bridge.sensors[1].swnodes[SWNODE_CIO2_ENDPOINT]),
+       PROPERTY_ENTRY_REF("remote-endpoint",
+                          &bridge.sensors[1].swnodes[SWNODE_SENSOR_ENDPOINT]),
+       PROPERTY_ENTRY_REF("remote-endpoint",
+                          &bridge.sensors[2].swnodes[SWNODE_CIO2_ENDPOINT]),
+       PROPERTY_ENTRY_REF("remote-endpoint",
+                          &bridge.sensors[2].swnodes[SWNODE_SENSOR_ENDPOINT]),
+       PROPERTY_ENTRY_REF("remote-endpoint",
+                          &bridge.sensors[3].swnodes[SWNODE_CIO2_ENDPOINT]),
+       PROPERTY_ENTRY_REF("remote-endpoint",
+                          &bridge.sensors[3].swnodes[SWNODE_SENSOR_ENDPOINT]),
+};
+
+static int read_acpi_block(struct device *dev, char *id, void *data, u32 size)
+{
+       struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+       struct acpi_handle *handle;
+       union acpi_object *obj;
+       acpi_status status;
+       int ret;
+
+       handle = ACPI_HANDLE(dev);
+
+       status = acpi_evaluate_object(handle, id, NULL, &buffer);
+       if (ACPI_FAILURE(status))
+               return -ENODEV;
+
+       obj = buffer.pointer;
+       if (!obj) {
+               dev_err(dev, "Couldn't locate ACPI buffer\n");
+               return -ENODEV;
+       }
+
+       if (obj->type != ACPI_TYPE_BUFFER) {
+               dev_err(dev, "Couldn't read ACPI buffer\n");
+               ret = -ENODEV;
+               goto out_free_buff;
+       }
+
+       if (obj->buffer.length > size) {
+               dev_err(dev, "Given buffer is too small\n");
+               ret = -ENODEV;
+               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 int get_acpi_ssdb_sensor_data(struct device *dev,
+                                    struct sensor_bios_data *sensor)
+{
+       struct sensor_bios_data_packed sensor_data;
+       int ret;
+
+       ret = read_acpi_block(dev, "SSDB", &sensor_data, sizeof(sensor_data));
+       if (ret < 0)
+               return ret;
+
+       sensor->link = sensor_data.link;
+       sensor->lanes = sensor_data.lanes;
+       sensor->mclkspeed = sensor_data.mclkspeed;
+       sensor->degree = sensor_data.degree;
+
+       return 0;
+}
+
+static int create_fwnode_properties(struct sensor *sensor,
+                                   struct sensor_bios_data *ssdb)
+{
+       struct property_entry *cio2_properties = sensor->cio2_properties;
+       struct property_entry *dev_properties = sensor->dev_properties;
+       struct property_entry *ep_properties = sensor->ep_properties;
+       int i;
+
+       /* device fwnode properties */
+       memset(dev_properties, 0, sizeof(struct property_entry) * 3);
+
+       dev_properties[0] = PROPERTY_ENTRY_U32("clock-frequency",
+                                              ssdb->mclkspeed);
+       dev_properties[1] = PROPERTY_ENTRY_U8("rotation", ssdb->degree);
+
+       /* endpoint fwnode properties */
+       memset(ep_properties, 0, sizeof(struct property_entry) * 4);
+
+       sensor->data_lanes = kmalloc_array(ssdb->lanes, sizeof(u32),
+                                          GFP_KERNEL);
+
+       if (!sensor->data_lanes)
+               return -ENOMEM;
+
+       for (i = 0; i < ssdb->lanes; i++)
+               sensor->data_lanes[i] = i + 1;
+
+       ep_properties[0] = PROPERTY_ENTRY_U32("bus-type", 5);
+       ep_properties[1] = PROPERTY_ENTRY_U32_ARRAY_LEN("data-lanes",
+                                                       sensor->data_lanes,
+                                                       ssdb->lanes);
+       ep_properties[2] = remote_endpoints[(bridge.n_sensors * 2) + 
ENDPOINT_SENSOR];
+
+       /* cio2 endpoint props */
+       memset(cio2_properties, 0, sizeof(struct property_entry) * 3);
+
+       cio2_properties[0] = PROPERTY_ENTRY_U32_ARRAY_LEN("data-lanes",
+                                                         sensor->data_lanes,
+                                                         ssdb->lanes);
+       cio2_properties[1] = remote_endpoints[(bridge.n_sensors * 2) + 
ENDPOINT_CIO2];
+
+       return 0;
+}
+
+static int create_connection_swnodes(struct sensor *sensor,
+                                    struct sensor_bios_data *ssdb)
+{
+       struct software_node *nodes = sensor->swnodes;
+
+       memset(nodes, 0, sizeof(struct software_node) * 6);
+
+       nodes[SWNODE_SENSOR_HID] = NODE_SENSOR(sensor->name,
+                                              sensor->dev_properties);
+       nodes[SWNODE_SENSOR_PORT] = NODE_PORT("port0",
+                                             &nodes[SWNODE_SENSOR_HID]);
+       nodes[SWNODE_SENSOR_ENDPOINT] = NODE_ENDPOINT("endpoint0",
+                                                     
&nodes[SWNODE_SENSOR_PORT],
+                                                     sensor->ep_properties);
+       nodes[SWNODE_CIO2_PORT] = NODE_PORT(port_names[ssdb->link],
+                                           &cio2_hid_node);
+       nodes[SWNODE_CIO2_ENDPOINT] = NODE_ENDPOINT("endpoint0",
+                                                   &nodes[SWNODE_CIO2_PORT],
+                                                   sensor->cio2_properties);
+
+       return 0;
+}
+
+static void cio2_bridge_unregister_sensors(void)
+{
+       struct sensor *sensor;
+       int i;
+
+       for (i = 0; i < bridge.n_sensors; i++) {
+               sensor = &bridge.sensors[i];
+
+               software_node_unregister_nodes_reverse(sensor->swnodes);
+
+               kfree(sensor->data_lanes);
+
+               put_device(sensor->dev);
+               acpi_dev_put(sensor->adev);
+       }
+}
+
+static int connect_supported_devices(struct pci_dev *cio2)
+{
+       struct sensor_bios_data ssdb;
+       struct fwnode_handle *fwnode;
+       struct acpi_device *adev;
+       struct sensor *sensor;
+       struct device *dev;
+       int i, ret;
+
+       ret = 0;
+       for (i = 0; i < ARRAY_SIZE(supported_devices); i++) {
+               adev = acpi_dev_get_first_match_dev(supported_devices[i], NULL, 
-1);
+               if (!adev)
+                       continue;
+
+               dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev);
+               if (!dev) {
+                       ret = -EPROBE_DEFER;
+                       goto err_rollback;
+               }
+
+               sensor = &bridge.sensors[bridge.n_sensors];
+               sensor->dev = dev;
+               sensor->adev = adev;
+
+               snprintf(sensor->name, ACPI_ID_LEN, "%s",
+                        supported_devices[i]);
+
+               ret = get_acpi_ssdb_sensor_data(dev, &ssdb);
+               if (ret)
+                       goto err_free_dev;
+
+               ret = create_fwnode_properties(sensor, &ssdb);
+               if (ret)
+                       goto err_free_dev;
+
+               ret = create_connection_swnodes(sensor, &ssdb);
+               if (ret)
+                       goto err_free_dev;
+
+               ret = software_node_register_nodes(sensor->swnodes);
+               if (ret)
+                       goto err_free_dev;
+
+               fwnode = 
software_node_fwnode(&sensor->swnodes[SWNODE_SENSOR_HID]);
+               if (!fwnode) {
+                       ret = -ENODEV;
+                       goto err_free_swnodes;
+               }
+
+               set_secondary_fwnode(dev, fwnode);
+
+               dev_info(&cio2->dev, "Found supported device %s\n",
+                        supported_devices[i]);
+
+               bridge.n_sensors++;
+               continue;
+       }
+
+       return ret;
+
+err_free_swnodes:
+       software_node_unregister_nodes_reverse(sensor->swnodes);
+err_free_dev:
+       put_device(dev);
+err_rollback:
+       acpi_dev_put(adev);
+
+       /*
+        * If an iteration of this loop results in -EPROBE_DEFER then
+        * we need to roll back any sensors that were successfully
+        * registered. Any other error and we'll skip that step, as
+        * it seems better to have one successfully connected sensor.
+        */
+
+       if (ret == -EPROBE_DEFER)
+               cio2_bridge_unregister_sensors();
+
+       return ret;
+}
+
+int cio2_bridge_build(struct pci_dev *cio2)
+{
+       struct fwnode_handle *fwnode;
+       int ret;
+
+       pci_dev_get(cio2);
+
+       ret = software_node_register(&cio2_hid_node);
+       if (ret < 0) {
+               dev_err(&cio2->dev, "Failed to register the CIO2 HID node\n");
+               goto err_put_cio2;
+       }
+
+       ret = connect_supported_devices(cio2);
+       if (ret == -EPROBE_DEFER)
+               goto err_unregister_cio2;
+
+       if (bridge.n_sensors == 0) {
+               ret = -EPROBE_DEFER;
+               goto err_unregister_cio2;
+       }
+
+       dev_info(&cio2->dev, "Connected %d cameras\n", bridge.n_sensors);
+
+       fwnode = software_node_fwnode(&cio2_hid_node);
+       if (!fwnode) {
+               dev_err(&cio2->dev,
+                       "Error getting fwnode from cio2 software_node\n");
+               ret = -ENODEV;
+               goto err_unregister_sensors;
+       }
+
+       set_secondary_fwnode(&cio2->dev, fwnode);
+
+       return 0;
+
+err_unregister_sensors:
+       cio2_bridge_unregister_sensors();
+err_unregister_cio2:
+       software_node_unregister(&cio2_hid_node);
+err_put_cio2:
+       pci_dev_put(cio2);
+
+       return ret;
+}
+
+void cio2_bridge_burn(struct pci_dev *cio2)
+{
+       pci_dev_put(cio2);
+
+       cio2_bridge_unregister_sensors();
+
+       software_node_unregister(&cio2_hid_node);
+}
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 000000000..077354ca8
--- /dev/null
+++ b/drivers/media/pci/intel/ipu3/cio2-bridge.h
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Author: Dan Scally <djrsca...@gmail.com> */
+#ifndef __CIO2_BRIDGE_H
+#define __CIO2_BRIDGE_H
+
+#define MAX_CONNECTED_DEVICES                  4
+#define SWNODE_SENSOR_HID                      0
+#define SWNODE_SENSOR_PORT                     1
+#define SWNODE_SENSOR_ENDPOINT                 2
+#define SWNODE_CIO2_PORT                       3
+#define SWNODE_CIO2_ENDPOINT                   4
+#define SWNODE_NULL_TERMINATOR                 5
+
+#define CIO2_HID                               "INT343E"
+#define CIO2_PCI_ID                            0x9d32
+
+#define ENDPOINT_SENSOR                                0
+#define ENDPOINT_CIO2                          1
+
+#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,                         \
+       })
+
+struct sensor {
+       char name[ACPI_ID_LEN];
+       struct device *dev;
+       struct acpi_device *adev;
+       struct software_node swnodes[6];
+       struct property_entry dev_properties[3];
+       struct property_entry ep_properties[4];
+       struct property_entry cio2_properties[3];
+       u32 *data_lanes;
+};
+
+struct cio2_bridge {
+       int n_sensors;
+       struct sensor sensors[MAX_CONNECTED_DEVICES];
+};
+
+/* Data representation as it is in ACPI SSDB buffer */
+struct sensor_bios_data_packed {
+       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__;
+
+/* Fields needed by bridge driver */
+struct sensor_bios_data {
+       struct device *dev;
+       u8 link;
+       u8 lanes;
+       u8 degree;
+       u32 mclkspeed;
+};
+
+#endif
diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c 
b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
index f68ef0f6b..827457110 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
@@ -1715,9 +1715,27 @@ static void cio2_queues_exit(struct cio2_device *cio2)
 static int cio2_pci_probe(struct pci_dev *pci_dev,
                          const struct pci_device_id *id)
 {
+       struct fwnode_handle *endpoint;
        struct cio2_device *cio2;
        int r;
 
+       /*
+        * 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.
+        *
+        * This may EPROBE_DEFER if supported devices are found defined in ACPI
+        * but not yet ready for use (either not attached to the i2c bus yet,
+        * or not done probing themselves).
+        */
+
+       endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(&pci_dev->dev), 
NULL);
+       if (!endpoint) {
+               r = cio2_bridge_build(pci_dev);
+               if (r)
+                       return r;
+       }
+
        cio2 = devm_kzalloc(&pci_dev->dev, sizeof(*cio2), GFP_KERNEL);
        if (!cio2)
                return -ENOMEM;
@@ -1825,6 +1843,9 @@ static void cio2_pci_remove(struct pci_dev *pci_dev)
 {
        struct cio2_device *cio2 = pci_get_drvdata(pci_dev);
 
+       if (is_software_node(dev_fwnode(&pci_dev->dev)))
+               cio2_bridge_burn(pci_dev);
+
        media_device_unregister(&cio2->media_dev);
        v4l2_async_notifier_unregister(&cio2->notifier);
        v4l2_async_notifier_cleanup(&cio2->notifier);
diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2.h 
b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
index 549b08f88..80a081d7e 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2.h
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
@@ -436,4 +436,13 @@ 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_build(struct pci_dev *cio2);
+       void cio2_bridge_burn(struct pci_dev *cio2);
+#else
+
+       int cio2_bridge_build(struct pci_dev *cio2) { return 0; }
+       void cio2_bridge_burn(struct pci_dev *cio2) { }
+#endif
+
 #endif
-- 
2.17.1

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