[RFC PATCH v3 9/9] ipu3-cio2: Add functionality allowing software_node connections to sensors on platforms designed for Windows

From: Daniel Scally <djrscally@gmail.com>
To: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org
Cc: linux.walleij@linaro.org,
	prabhakar.mahadev-lad.rj@bp.renesas.com,
	heikki.krogerus@linux.intel.com, dmitry.torokhov@gmail.com,
	laurent.pinchart+renesas@ideasonboard.com,
	kieran.bingham+renesas@ideasonboard.com,
	jacopo+renesas@jmondi.org, robh@kernel.org, davem@davemloft.net,
	linux@rasmusvillemoes.dk, andriy.shevchenko@linux.intel.com,
	sergey.senozhatsky@gmail.com, rostedt@goodmis.org,
	pmladek@suse.com, mchehab@kernel.org, tian.shu.qiu@intel.com,
	bingbu.cao@intel.com, sakari.ailus@linux.intel.com,
	yong.zhi@intel.com, rafael@kernel.org,
	gregkh@linuxfoundation.org, kitakar@gmail.com,
	dan.carpenter@oracle.org
Subject: [RFC PATCH v3 9/9] ipu3-cio2: Add functionality allowing software_node connections to sensors on platforms designed for Windows
Date: Mon, 19 Oct 2020 23:59:03 +0100	[thread overview]
Message-ID: <20201019225903.14276-10-djrscally@gmail.com> (raw)
In-Reply-To: <20201019225903.14276-1-djrscally@gmail.com>

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 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@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 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@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 <djrscally@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

