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>
Reviewed-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
Reviewed-by: Andy Shevchenko <andy.shevche...@gmail.com>
Signed-off-by: Daniel Scally <djrsca...@gmail.com>
---
Changes in v4:

        - Added local definition of CIO2_MAX_LANES
        - Added some includes to cio2-bridge.h
        - Moved the inner loop of cio2_bridge_connect_sensors() to a
          standalone function
        - Altered macros to make explicit assignments to members rather
          than relying on position
        - A couple of minor format changes, mostly line wrapping

 MAINTAINERS                                   |   1 +
 drivers/media/pci/intel/ipu3/Kconfig          |  18 ++
 drivers/media/pci/intel/ipu3/Makefile         |   1 +
 drivers/media/pci/intel/ipu3/cio2-bridge.c    | 302 ++++++++++++++++++
 drivers/media/pci/intel/ipu3/cio2-bridge.h    | 125 ++++++++
 drivers/media/pci/intel/ipu3/ipu3-cio2-main.c |  33 ++
 drivers/media/pci/intel/ipu3/ipu3-cio2.h      |   6 +
 7 files changed, 486 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....@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..96a2231b16ad 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 the 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..3a7bedb08f66
--- /dev/null
+++ b/drivers/media/pci/intel/ipu3/cio2-bridge.c
@@ -0,0 +1,302 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dan Scally <djrsca...@gmail.com> */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/pci.h>
+#include <linux/property.h>
+#include <media/v4l2-fwnode.h>
+
+#include "cio2-bridge.h"
+
+/*
+ * Extend this array with ACPI Hardware IDs 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 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",
+       .link_frequencies = "link-frequencies",
+};
+
+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 = 0;
+
+       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);
+
+out_free_buff:
+       kfree(buffer.pointer);
+       return ret;
+}
+
+static void cio2_bridge_create_fwnode_properties(
+       struct cio2_sensor *sensor,
+       const struct cio2_sensor_config *cfg)
+{
+       unsigned int i;
+
+       sensor->prop_names = prop_names;
+
+       for (i = 0; i < CIO2_MAX_LANES; 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,
+                                       V4L2_FWNODE_BUS_TYPE_CSI2_DPHY);
+       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,
+                sizeof(sensor->node_names.remote_port),
+                SWNODE_GRAPH_PORT_NAME_FMT, sensor->ssdb.link);
+       snprintf(sensor->node_names.port,
+                sizeof(sensor->node_names.port),
+                SWNODE_GRAPH_PORT_NAME_FMT, 0); /* Always port 0 */
+       snprintf(sensor->node_names.endpoint,
+                sizeof(sensor->node_names.endpoint),
+                SWNODE_GRAPH_ENDPOINT_NAME_FMT, 0); /* And endpoint 0 */
+}
+
+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_sensor(const struct cio2_sensor_config *cfg,
+                                     struct cio2_bridge *bridge,
+                                     struct pci_dev *cio2)
+{
+       struct fwnode_handle *fwnode;
+       struct cio2_sensor *sensor;
+       struct acpi_device *adev;
+       int ret;
+
+       for_each_acpi_dev_match(adev, cfg->hid, NULL, -1) {
+               if (bridge->n_sensors >= CIO2_NUM_PORTS) {
+                       dev_err(&cio2->dev, "Exceeded available CIO2 ports\n");
+                       cio2_bridge_unregister_sensors(bridge);
+                       ret = -EINVAL;
+                       goto err_out;
+               }
+
+               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)
+                       goto err_put_adev;
+
+               if (sensor->ssdb.lanes > CIO2_MAX_LANES) {
+                       dev_err(&adev->dev,
+                               "Number of lanes in SSDB is invalid\n");
+                       ret = -EINVAL;
+                       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 0;
+
+err_free_swnodes:
+       software_node_unregister_nodes(sensor->swnodes);
+err_put_adev:
+       acpi_dev_put(sensor->adev);
+err_out:
+       return ret;
+}
+
+static int cio2_bridge_connect_sensors(struct cio2_bridge *bridge,
+                                      struct pci_dev *cio2)
+{
+       unsigned int i;
+       int ret;
+
+       for (i = 0; i < ARRAY_SIZE(cio2_supported_sensors); i++) {
+               const struct cio2_sensor_config *cfg = 
&cio2_supported_sensors[i];
+
+               ret = cio2_bridge_connect_sensor(cfg, bridge, cio2);
+               if (ret)
+                       goto err_unregister_sensors;
+       }
+
+       return 0;
+
+err_unregister_sensors:
+       cio2_bridge_unregister_sensors(bridge);
+       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..3ec4ed44aced
--- /dev/null
+++ b/drivers/media/pci/intel/ipu3/cio2-bridge.h
@@ -0,0 +1,125 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Author: Dan Scally <djrsca...@gmail.com> */
+#ifndef __CIO2_BRIDGE_H
+#define __CIO2_BRIDGE_H
+
+#include <linux/property.h>
+#include <linux/types.h>
+
+#include "ipu3-cio2.h"
+
+#define CIO2_HID                               "INT343E"
+#define CIO2_MAX_LANES                         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) {         \
+               .name = _PORT,                  \
+               .parent = _SENSOR_NODE,         \
+       })
+
+#define NODE_ENDPOINT(_EP, _PORT, _PROPS)      \
+       ((const struct software_node) {         \
+               .name = _EP,                    \
+               .parent = _PORT,                \
+               .properties = _PROPS,           \
+       })
+
+enum cio2_sensor_swnodes {
+       SWNODE_SENSOR_HID,
+       SWNODE_SENSOR_PORT,
+       SWNODE_SENSOR_ENDPOINT,
+       SWNODE_CIO2_PORT,
+       SWNODE_CIO2_ENDPOINT,
+       SWNODE_COUNT
+};
+
+/* 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;
+
+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..50c7ea467795 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 +1732,22 @@ 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 62187ab5ae43..dc3e343a37fb 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2.h
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
@@ -455,4 +455,10 @@ 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
-- 
2.25.1

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