Date:   Mon, 19 Oct 2020 23:59:03 +0100
From:   Daniel Scally <djrscally@...il.com>
To:     linux-kernel@...r.kernel.org, linux-media@...r.kernel.org
Cc:     linux.walleij@...aro.org, prabhakar.mahadev-lad.rj@...renesas.com,
        heikki.krogerus@...ux.intel.com, dmitry.torokhov@...il.com,
        laurent.pinchart+renesas@...asonboard.com,
        kieran.bingham+renesas@...asonboard.com, jacopo+renesas@...ndi.org,
        robh@...nel.org, davem@...emloft.net, linux@...musvillemoes.dk,
        andriy.shevchenko@...ux.intel.com, sergey.senozhatsky@...il.com,
        rostedt@...dmis.org, pmladek@...e.com, mchehab@...nel.org,
        tian.shu.qiu@...el.com, bingbu.cao@...el.com,
        sakari.ailus@...ux.intel.com, yong.zhi@...el.com,
        rafael@...nel.org, gregkh@...uxfoundation.org, kitakar@...il.com,
        dan.carpenter@...cle.org
Subject: [RFC PATCH v3 9/9] ipu3-cio2: Add functionality allowing software_node connections to sensors on platforms designed for Windows

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@...ux.microsoft.com>
Signed-off-by: Daniel Scally <djrscally@...il.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.zhi@...el.com>
 M:	Sakari Ailus <sakari.ailus@...ux.intel.com>
 M:	Bingbu Cao <bingbu.cao@...el.com>
+M:	Dan Scally <djrscally@...il.com>
 R:	Tianshu Qiu <tian.shu.qiu@...el.com>
 L:	linux-media@...r.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 <djrscally@...il.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 <djrscally@...il.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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