staging: greybus: move the greybus core to drivers/greybus

The Greybus core code has been stable for a long time, and has been
shipping for many years in millions of phones.  With the advent of a
recent Google Summer of Code project, and a number of new devices in the
works from various companies, it is time to get the core greybus code
out of staging as it really is going to be with us for a while.

Cc: Johan Hovold <johan@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: greybus-dev@lists.linaro.org
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Alex Elder <elder@kernel.org>
Link: https://lore.kernel.org/r/20190825055429.18547-9-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

15 files changed, 7839 insertions, 0 deletions

diff --git a/drivers/greybus/Kconfig b/drivers/greybus/Kconfig
new file mode 100644
index 000000000000..158d8893114c
--- /dev/null
+++ b/drivers/greybus/Kconfig
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0
+menuconfig GREYBUS
+	tristate "Greybus support"
+	depends on SYSFS
+	---help---
+	  This option enables the Greybus driver core.  Greybus is an
+	  hardware protocol that was designed to provide Unipro with a
+	  sane application layer.  It was originally designed for the
+	  ARA project, a module phone system, but has shown up in other
+	  phones, and can be tunneled over other busses in order to
+	  control hardware devices.
+
+	  Say Y here to enable support for these types of drivers.
+
+	  To compile this code as a module, chose M here: the module
+	  will be called greybus.ko
diff --git a/drivers/greybus/Makefile b/drivers/greybus/Makefile
new file mode 100644
index 000000000000..03b22616ec7d
--- /dev/null
+++ b/drivers/greybus/Makefile
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0
+# Greybus core
+greybus-y :=	core.o		\
+		debugfs.o	\
+		hd.o		\
+		manifest.o	\
+		module.o	\
+		interface.o	\
+		bundle.o	\
+		connection.o	\
+		control.o	\
+		svc.o		\
+		svc_watchdog.o	\
+		operation.o
+
+obj-$(CONFIG_GREYBUS)		+= greybus.o
+
+# needed for trace events
+ccflags-y += -I$(src)
diff --git a/drivers/greybus/bundle.c b/drivers/greybus/bundle.c
new file mode 100644
index 000000000000..84660729538b
--- /dev/null
+++ b/drivers/greybus/bundle.c
@@ -0,0 +1,252 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Greybus bundles
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ */
+
+#include <linux/greybus.h>
+#include "greybus_trace.h"
+
+static ssize_t bundle_class_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+
+	return sprintf(buf, "0x%02x\n", bundle->class);
+}
+static DEVICE_ATTR_RO(bundle_class);
+
+static ssize_t bundle_id_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+
+	return sprintf(buf, "%u\n", bundle->id);
+}
+static DEVICE_ATTR_RO(bundle_id);
+
+static ssize_t state_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+
+	if (!bundle->state)
+		return sprintf(buf, "\n");
+
+	return sprintf(buf, "%s\n", bundle->state);
+}
+
+static ssize_t state_store(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t size)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+
+	kfree(bundle->state);
+	bundle->state = kstrdup(buf, GFP_KERNEL);
+	if (!bundle->state)
+		return -ENOMEM;
+
+	/* Tell userspace that the file contents changed */
+	sysfs_notify(&bundle->dev.kobj, NULL, "state");
+
+	return size;
+}
+static DEVICE_ATTR_RW(state);
+
+static struct attribute *bundle_attrs[] = {
+	&dev_attr_bundle_class.attr,
+	&dev_attr_bundle_id.attr,
+	&dev_attr_state.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(bundle);
+
+static struct gb_bundle *gb_bundle_find(struct gb_interface *intf,
+					u8 bundle_id)
+{
+	struct gb_bundle *bundle;
+
+	list_for_each_entry(bundle, &intf->bundles, links) {
+		if (bundle->id == bundle_id)
+			return bundle;
+	}
+
+	return NULL;
+}
+
+static void gb_bundle_release(struct device *dev)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+
+	trace_gb_bundle_release(bundle);
+
+	kfree(bundle->state);
+	kfree(bundle->cport_desc);
+	kfree(bundle);
+}
+
+#ifdef CONFIG_PM
+static void gb_bundle_disable_all_connections(struct gb_bundle *bundle)
+{
+	struct gb_connection *connection;
+
+	list_for_each_entry(connection, &bundle->connections, bundle_links)
+		gb_connection_disable(connection);
+}
+
+static void gb_bundle_enable_all_connections(struct gb_bundle *bundle)
+{
+	struct gb_connection *connection;
+
+	list_for_each_entry(connection, &bundle->connections, bundle_links)
+		gb_connection_enable(connection);
+}
+
+static int gb_bundle_suspend(struct device *dev)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+	const struct dev_pm_ops *pm = dev->driver->pm;
+	int ret;
+
+	if (pm && pm->runtime_suspend) {
+		ret = pm->runtime_suspend(&bundle->dev);
+		if (ret)
+			return ret;
+	} else {
+		gb_bundle_disable_all_connections(bundle);
+	}
+
+	ret = gb_control_bundle_suspend(bundle->intf->control, bundle->id);
+	if (ret) {
+		if (pm && pm->runtime_resume)
+			ret = pm->runtime_resume(dev);
+		else
+			gb_bundle_enable_all_connections(bundle);
+
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gb_bundle_resume(struct device *dev)
+{
+	struct gb_bundle *bundle = to_gb_bundle(dev);
+	const struct dev_pm_ops *pm = dev->driver->pm;
+	int ret;
+
+	ret = gb_control_bundle_resume(bundle->intf->control, bundle->id);
+	if (ret)
+		return ret;
+
+	if (pm && pm->runtime_resume) {
+		ret = pm->runtime_resume(dev);
+		if (ret)
+			return ret;
+	} else {
+		gb_bundle_enable_all_connections(bundle);
+	}
+
+	return 0;
+}
+
+static int gb_bundle_idle(struct device *dev)
+{
+	pm_runtime_mark_last_busy(dev);
+	pm_request_autosuspend(dev);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops gb_bundle_pm_ops = {
+	SET_RUNTIME_PM_OPS(gb_bundle_suspend, gb_bundle_resume, gb_bundle_idle)
+};
+
+struct device_type greybus_bundle_type = {
+	.name =		"greybus_bundle",
+	.release =	gb_bundle_release,
+	.pm =		&gb_bundle_pm_ops,
+};
+
+/*
+ * Create a gb_bundle structure to represent a discovered
+ * bundle.  Returns a pointer to the new bundle or a null
+ * pointer if a failure occurs due to memory exhaustion.
+ */
+struct gb_bundle *gb_bundle_create(struct gb_interface *intf, u8 bundle_id,
+				   u8 class)
+{
+	struct gb_bundle *bundle;
+
+	if (bundle_id == BUNDLE_ID_NONE) {
+		dev_err(&intf->dev, "can't use bundle id %u\n", bundle_id);
+		return NULL;
+	}
+
+	/*
+	 * Reject any attempt to reuse a bundle id.  We initialize
+	 * these serially, so there's no need to worry about keeping
+	 * the interface bundle list locked here.
+	 */
+	if (gb_bundle_find(intf, bundle_id)) {
+		dev_err(&intf->dev, "duplicate bundle id %u\n", bundle_id);
+		return NULL;
+	}
+
+	bundle = kzalloc(sizeof(*bundle), GFP_KERNEL);
+	if (!bundle)
+		return NULL;
+
+	bundle->intf = intf;
+	bundle->id = bundle_id;
+	bundle->class = class;
+	INIT_LIST_HEAD(&bundle->connections);
+
+	bundle->dev.parent = &intf->dev;
+	bundle->dev.bus = &greybus_bus_type;
+	bundle->dev.type = &greybus_bundle_type;
+	bundle->dev.groups = bundle_groups;
+	bundle->dev.dma_mask = intf->dev.dma_mask;
+	device_initialize(&bundle->dev);
+	dev_set_name(&bundle->dev, "%s.%d", dev_name(&intf->dev), bundle_id);
+
+	list_add(&bundle->links, &intf->bundles);
+
+	trace_gb_bundle_create(bundle);
+
+	return bundle;
+}
+
+int gb_bundle_add(struct gb_bundle *bundle)
+{
+	int ret;
+
+	ret = device_add(&bundle->dev);
+	if (ret) {
+		dev_err(&bundle->dev, "failed to register bundle: %d\n", ret);
+		return ret;
+	}
+
+	trace_gb_bundle_add(bundle);
+
+	return 0;
+}
+
+/*
+ * Tear down a previously set up bundle.
+ */
+void gb_bundle_destroy(struct gb_bundle *bundle)
+{
+	trace_gb_bundle_destroy(bundle);
+
+	if (device_is_registered(&bundle->dev))
+		device_del(&bundle->dev);
+
+	list_del(&bundle->links);
+
+	put_device(&bundle->dev);
+}
diff --git a/drivers/greybus/connection.c b/drivers/greybus/connection.c
new file mode 100644
index 000000000000..fc8f57f97ce6
--- /dev/null
+++ b/drivers/greybus/connection.c
@@ -0,0 +1,942 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Greybus connections
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ */
+
+#include <linux/workqueue.h>
+#include <linux/greybus.h>
+
+#include "greybus_trace.h"
+
+#define GB_CONNECTION_CPORT_QUIESCE_TIMEOUT	1000
+
+static void gb_connection_kref_release(struct kref *kref);
+
+static DEFINE_SPINLOCK(gb_connections_lock);
+static DEFINE_MUTEX(gb_connection_mutex);
+
+/* Caller holds gb_connection_mutex. */
+static bool gb_connection_cport_in_use(struct gb_interface *intf, u16 cport_id)
+{
+	struct gb_host_device *hd = intf->hd;
+	struct gb_connection *connection;
+
+	list_for_each_entry(connection, &hd->connections, hd_links) {
+		if (connection->intf == intf &&
+		    connection->intf_cport_id == cport_id)
+			return true;
+	}
+
+	return false;
+}
+
+static void gb_connection_get(struct gb_connection *connection)
+{
+	kref_get(&connection->kref);
+
+	trace_gb_connection_get(connection);
+}
+
+static void gb_connection_put(struct gb_connection *connection)
+{
+	trace_gb_connection_put(connection);
+
+	kref_put(&connection->kref, gb_connection_kref_release);
+}
+
+/*
+ * Returns a reference-counted pointer to the connection if found.
+ */
+static struct gb_connection *
+gb_connection_hd_find(struct gb_host_device *hd, u16 cport_id)
+{
+	struct gb_connection *connection;
+	unsigned long flags;
+
+	spin_lock_irqsave(&gb_connections_lock, flags);
+	list_for_each_entry(connection, &hd->connections, hd_links)
+		if (connection->hd_cport_id == cport_id) {
+			gb_connection_get(connection);
+			goto found;
+		}
+	connection = NULL;
+found:
+	spin_unlock_irqrestore(&gb_connections_lock, flags);
+
+	return connection;
+}
+
+/*
+ * Callback from the host driver to let us know that data has been
+ * received on the bundle.
+ */
+void greybus_data_rcvd(struct gb_host_device *hd, u16 cport_id,
+		       u8 *data, size_t length)
+{
+	struct gb_connection *connection;
+
+	trace_gb_hd_in(hd);
+
+	connection = gb_connection_hd_find(hd, cport_id);
+	if (!connection) {
+		dev_err(&hd->dev,
+			"nonexistent connection (%zu bytes dropped)\n", length);
+		return;
+	}
+	gb_connection_recv(connection, data, length);
+	gb_connection_put(connection);
+}
+EXPORT_SYMBOL_GPL(greybus_data_rcvd);
+
+static void gb_connection_kref_release(struct kref *kref)
+{
+	struct gb_connection *connection;
+
+	connection = container_of(kref, struct gb_connection, kref);
+
+	trace_gb_connection_release(connection);
+
+	kfree(connection);
+}
+
+static void gb_connection_init_name(struct gb_connection *connection)
+{
+	u16 hd_cport_id = connection->hd_cport_id;
+	u16 cport_id = 0;
+	u8 intf_id = 0;
+
+	if (connection->intf) {
+		intf_id = connection->intf->interface_id;
+		cport_id = connection->intf_cport_id;
+	}
+
+	snprintf(connection->name, sizeof(connection->name),
+		 "%u/%u:%u", hd_cport_id, intf_id, cport_id);
+}
+
+/*
+ * _gb_connection_create() - create a Greybus connection
+ * @hd:			host device of the connection
+ * @hd_cport_id:	host-device cport id, or -1 for dynamic allocation
+ * @intf:		remote interface, or NULL for static connections
+ * @bundle:		remote-interface bundle (may be NULL)
+ * @cport_id:		remote-interface cport id, or 0 for static connections
+ * @handler:		request handler (may be NULL)
+ * @flags:		connection flags
+ *
+ * Create a Greybus connection, representing the bidirectional link
+ * between a CPort on a (local) Greybus host device and a CPort on
+ * another Greybus interface.
+ *
+ * A connection also maintains the state of operations sent over the
+ * connection.
+ *
+ * Serialised against concurrent create and destroy using the
+ * gb_connection_mutex.
+ *
+ * Return: A pointer to the new connection if successful, or an ERR_PTR
+ * otherwise.
+ */
+static struct gb_connection *
+_gb_connection_create(struct gb_host_device *hd, int hd_cport_id,
+		      struct gb_interface *intf,
+		      struct gb_bundle *bundle, int cport_id,
+		      gb_request_handler_t handler,
+		      unsigned long flags)
+{
+	struct gb_connection *connection;
+	int ret;
+
+	mutex_lock(&gb_connection_mutex);
+
+	if (intf && gb_connection_cport_in_use(intf, cport_id)) {
+		dev_err(&intf->dev, "cport %u already in use\n", cport_id);
+		ret = -EBUSY;
+		goto err_unlock;
+	}
+
+	ret = gb_hd_cport_allocate(hd, hd_cport_id, flags);
+	if (ret < 0) {
+		dev_err(&hd->dev, "failed to allocate cport: %d\n", ret);
+		goto err_unlock;
+	}
+	hd_cport_id = ret;
+
+	connection = kzalloc(sizeof(*connection), GFP_KERNEL);
+	if (!connection) {
+		ret = -ENOMEM;
+		goto err_hd_cport_release;
+	}
+
+	connection->hd_cport_id = hd_cport_id;
+	connection->intf_cport_id = cport_id;
+	connection->hd = hd;
+	connection->intf = intf;
+	connection->bundle = bundle;
+	connection->handler = handler;
+	connection->flags = flags;
+	if (intf && (intf->quirks & GB_INTERFACE_QUIRK_NO_CPORT_FEATURES))
+		connection->flags |= GB_CONNECTION_FLAG_NO_FLOWCTRL;
+	connection->state = GB_CONNECTION_STATE_DISABLED;
+
+	atomic_set(&connection->op_cycle, 0);
+	mutex_init(&connection->mutex);
+	spin_lock_init(&connection->lock);
+	INIT_LIST_HEAD(&connection->operations);
+
+	connection->wq = alloc_workqueue("%s:%d", WQ_UNBOUND, 1,
+					 dev_name(&hd->dev), hd_cport_id);
+	if (!connection->wq) {
+		ret = -ENOMEM;
+		goto err_free_connection;
+	}
+
+	kref_init(&connection->kref);
+
+	gb_connection_init_name(connection);
+
+	spin_lock_irq(&gb_connections_lock);
+	list_add(&connection->hd_links, &hd->connections);
+
+	if (bundle)
+		list_add(&connection->bundle_links, &bundle->connections);
+	else
+		INIT_LIST_HEAD(&connection->bundle_links);
+
+	spin_unlock_irq(&gb_connections_lock);
+
+	mutex_unlock(&gb_connection_mutex);
+
+	trace_gb_connection_create(connection);
+
+	return connection;
+
+err_free_connection:
+	kfree(connection);
+err_hd_cport_release:
+	gb_hd_cport_release(hd, hd_cport_id);
+err_unlock:
+	mutex_unlock(&gb_connection_mutex);
+
+	return ERR_PTR(ret);
+}
+
+struct gb_connection *
+gb_connection_create_static(struct gb_host_device *hd, u16 hd_cport_id,
+			    gb_request_handler_t handler)
+{
+	return _gb_connection_create(hd, hd_cport_id, NULL, NULL, 0, handler,
+				     GB_CONNECTION_FLAG_HIGH_PRIO);
+}
+
+struct gb_connection *
+gb_connection_create_control(struct gb_interface *intf)
+{
+	return _gb_connection_create(intf->hd, -1, intf, NULL, 0, NULL,
+				     GB_CONNECTION_FLAG_CONTROL |
+				     GB_CONNECTION_FLAG_HIGH_PRIO);
+}
+
+struct gb_connection *
+gb_connection_create(struct gb_bundle *bundle, u16 cport_id,
+		     gb_request_handler_t handler)
+{
+	struct gb_interface *intf = bundle->intf;
+
+	return _gb_connection_create(intf->hd, -1, intf, bundle, cport_id,
+				     handler, 0);
+}
+EXPORT_SYMBOL_GPL(gb_connection_create);
+
+struct gb_connection *
+gb_connection_create_flags(struct gb_bundle *bundle, u16 cport_id,
+			   gb_request_handler_t handler,
+			   unsigned long flags)
+{
+	struct gb_interface *intf = bundle->intf;
+
+	if (WARN_ON_ONCE(flags & GB_CONNECTION_FLAG_CORE_MASK))
+		flags &= ~GB_CONNECTION_FLAG_CORE_MASK;
+
+	return _gb_connection_create(intf->hd, -1, intf, bundle, cport_id,
+				     handler, flags);
+}
+EXPORT_SYMBOL_GPL(gb_connection_create_flags);
+
+struct gb_connection *
+gb_connection_create_offloaded(struct gb_bundle *bundle, u16 cport_id,
+			       unsigned long flags)
+{
+	flags |= GB_CONNECTION_FLAG_OFFLOADED;
+
+	return gb_connection_create_flags(bundle, cport_id, NULL, flags);
+}
+EXPORT_SYMBOL_GPL(gb_connection_create_offloaded);
+
+static int gb_connection_hd_cport_enable(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	int ret;
+
+	if (!hd->driver->cport_enable)
+		return 0;
+
+	ret = hd->driver->cport_enable(hd, connection->hd_cport_id,
+				       connection->flags);
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to enable host cport: %d\n",
+			connection->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void gb_connection_hd_cport_disable(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	int ret;
+
+	if (!hd->driver->cport_disable)
+		return;
+
+	ret = hd->driver->cport_disable(hd, connection->hd_cport_id);
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to disable host cport: %d\n",
+			connection->name, ret);
+	}
+}
+
+static int gb_connection_hd_cport_connected(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	int ret;
+
+	if (!hd->driver->cport_connected)
+		return 0;
+
+	ret = hd->driver->cport_connected(hd, connection->hd_cport_id);
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to set connected state: %d\n",
+			connection->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gb_connection_hd_cport_flush(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	int ret;
+
+	if (!hd->driver->cport_flush)
+		return 0;
+
+	ret = hd->driver->cport_flush(hd, connection->hd_cport_id);
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to flush host cport: %d\n",
+			connection->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gb_connection_hd_cport_quiesce(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	size_t peer_space;
+	int ret;
+
+	if (!hd->driver->cport_quiesce)
+		return 0;
+
+	peer_space = sizeof(struct gb_operation_msg_hdr) +
+			sizeof(struct gb_cport_shutdown_request);
+
+	if (connection->mode_switch)
+		peer_space += sizeof(struct gb_operation_msg_hdr);
+
+	if (!hd->driver->cport_quiesce)
+		return 0;
+
+	ret = hd->driver->cport_quiesce(hd, connection->hd_cport_id,
+					peer_space,
+					GB_CONNECTION_CPORT_QUIESCE_TIMEOUT);
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to quiesce host cport: %d\n",
+			connection->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gb_connection_hd_cport_clear(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	int ret;
+
+	if (!hd->driver->cport_clear)
+		return 0;
+
+	ret = hd->driver->cport_clear(hd, connection->hd_cport_id);
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to clear host cport: %d\n",
+			connection->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * Request the SVC to create a connection from AP's cport to interface's
+ * cport.
+ */
+static int
+gb_connection_svc_connection_create(struct gb_connection *connection)
+{
+	struct gb_host_device *hd = connection->hd;
+	struct gb_interface *intf;
+	u8 cport_flags;
+	int ret;
+
+	if (gb_connection_is_static(connection))
+		return 0;
+
+	intf = connection->intf;
+
+	/*
+	 * Enable either E2EFC or CSD, unless no flow control is requested.
+	 */
+	cport_flags = GB_SVC_CPORT_FLAG_CSV_N;
+	if (gb_connection_flow_control_disabled(connection)) {
+		cport_flags |= GB_SVC_CPORT_FLAG_CSD_N;
+	} else if (gb_connection_e2efc_enabled(connection)) {
+		cport_flags |= GB_SVC_CPORT_FLAG_CSD_N |
+				GB_SVC_CPORT_FLAG_E2EFC;
+	}
+
+	ret = gb_svc_connection_create(hd->svc,
+				       hd->svc->ap_intf_id,
+				       connection->hd_cport_id,
+				       intf->interface_id,
+				       connection->intf_cport_id,
+				       cport_flags);
+	if (ret) {
+		dev_err(&connection->hd->dev,
+			"%s: failed to create svc connection: %d\n",
+			connection->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void
+gb_connection_svc_connection_destroy(struct gb_connection *connection)
+{
+	if (gb_connection_is_static(connection))
+		return;
+
+	gb_svc_connection_destroy(connection->hd->svc,
+				  connection->hd->svc->ap_intf_id,
+				  connection->hd_cport_id,
+				  connection->intf->interface_id,
+				  connection->intf_cport_id);
+}
+
+/* Inform Interface about active CPorts */
+static int gb_connection_control_connected(struct gb_connection *connection)
+{
+	struct gb_control *control;
+	u16 cport_id = connection->intf_cport_id;
+	int ret;
+
+	if (gb_connection_is_static(connection))
+		return 0;
+
+	if (gb_connection_is_control(connection))
+		return 0;
+
+	control = connection->intf->control;
+
+	ret = gb_control_connected_operation(control, cport_id);
+	if (ret) {
+		dev_err(&connection->bundle->dev,
+			"failed to connect cport: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void
+gb_connection_control_disconnecting(struct gb_connection *connection)
+{
+	struct gb_control *control;
+	u16 cport_id = connection->intf_cport_id;
+	int ret;
+
+	if (gb_connection_is_static(connection))
+		return;
+
+	control = connection->intf->control;
+
+	ret = gb_control_disconnecting_operation(control, cport_id);
+	if (ret) {
+		dev_err(&connection->hd->dev,
+			"%s: failed to send disconnecting: %d\n",
+			connection->name, ret);
+	}
+}
+
+static void
+gb_connection_control_disconnected(struct gb_connection *connection)
+{
+	struct gb_control *control;
+	u16 cport_id = connection->intf_cport_id;
+	int ret;
+
+	if (gb_connection_is_static(connection))
+		return;
+
+	control = connection->intf->control;
+
+	if (gb_connection_is_control(connection)) {
+		if (connection->mode_switch) {
+			ret = gb_control_mode_switch_operation(control);
+			if (ret) {
+				/*
+				 * Allow mode switch to time out waiting for
+				 * mailbox event.
+				 */
+				return;
+			}
+		}
+
+		return;
+	}
+
+	ret = gb_control_disconnected_operation(control, cport_id);
+	if (ret) {
+		dev_warn(&connection->bundle->dev,
+			 "failed to disconnect cport: %d\n", ret);
+	}
+}
+
+static int gb_connection_shutdown_operation(struct gb_connection *connection,
+					    u8 phase)
+{
+	struct gb_cport_shutdown_request *req;
+	struct gb_operation *operation;
+	int ret;
+
+	operation = gb_operation_create_core(connection,
+					     GB_REQUEST_TYPE_CPORT_SHUTDOWN,
+					     sizeof(*req), 0, 0,
+					     GFP_KERNEL);
+	if (!operation)
+		return -ENOMEM;
+
+	req = operation->request->payload;
+	req->phase = phase;
+
+	ret = gb_operation_request_send_sync(operation);
+
+	gb_operation_put(operation);
+
+	return ret;
+}
+
+static int gb_connection_cport_shutdown(struct gb_connection *connection,
+					u8 phase)
+{
+	struct gb_host_device *hd = connection->hd;
+	const struct gb_hd_driver *drv = hd->driver;
+	int ret;
+
+	if (gb_connection_is_static(connection))
+		return 0;
+
+	if (gb_connection_is_offloaded(connection)) {
+		if (!drv->cport_shutdown)
+			return 0;
+
+		ret = drv->cport_shutdown(hd, connection->hd_cport_id, phase,
+					  GB_OPERATION_TIMEOUT_DEFAULT);
+	} else {
+		ret = gb_connection_shutdown_operation(connection, phase);
+	}
+
+	if (ret) {
+		dev_err(&hd->dev, "%s: failed to send cport shutdown (phase %d): %d\n",
+			connection->name, phase, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int
+gb_connection_cport_shutdown_phase_1(struct gb_connection *connection)
+{
+	return gb_connection_cport_shutdown(connection, 1);
+}
+
+static int
+gb_connection_cport_shutdown_phase_2(struct gb_connection *connection)
+{
+	return gb_connection_cport_shutdown(connection, 2);
+}
+
+/*
+ * Cancel all active operations on a connection.
+ *
+ * Locking: Called with connection lock held and state set to DISABLED or
+ * DISCONNECTING.
+ */
+static void gb_connection_cancel_operations(struct gb_connection *connection,
+					    int errno)
+	__must_hold(&connection->lock)
+{
+	struct gb_operation *operation;
+
+	while (!list_empty(&connection->operations)) {
+		operation = list_last_entry(&connection->operations,
+					    struct gb_operation, links);
+		gb_operation_get(operation);
+		spin_unlock_irq(&connection->lock);
+
+		if (gb_operation_is_incoming(operation))
+			gb_operation_cancel_incoming(operation, errno);
+		else
+			gb_operation_cancel(operation, errno);
+
+		gb_operation_put(operation);
+
+		spin_lock_irq(&connection->lock);
+	}
+}
+
+/*
+ * Cancel all active incoming operations on a connection.
+ *
+ * Locking: Called with connection lock held and state set to ENABLED_TX.
+ */
+static void
+gb_connection_flush_incoming_operations(struct gb_connection *connection,
+					int errno)
+	__must_hold(&connection->lock)
+{
+	struct gb_operation *operation;
+	bool incoming;
+
+	while (!list_empty(&connection->operations)) {
+		incoming = false;
+		list_for_each_entry(operation, &connection->operations,
+				    links) {
+			if (gb_operation_is_incoming(operation)) {
+				gb_operation_get(operation);
+				incoming = true;
+				break;
+			}
+		}
+
+		if (!incoming)
+			break;
+
+		spin_unlock_irq(&connection->lock);
+
+		/* FIXME: flush, not cancel? */
+		gb_operation_cancel_incoming(operation, errno);
+		gb_operation_put(operation);
+
+		spin_lock_irq(&connection->lock);
+	}
+}
+
+/*
+ * _gb_connection_enable() - enable a connection
+ * @connection:		connection to enable
+ * @rx:			whether to enable incoming requests
+ *
+ * Connection-enable helper for DISABLED->ENABLED, DISABLED->ENABLED_TX, and
+ * ENABLED_TX->ENABLED state transitions.
+ *
+ * Locking: Caller holds connection->mutex.
+ */
+static int _gb_connection_enable(struct gb_connection *connection, bool rx)
+{
+	int ret;
+
+	/* Handle ENABLED_TX -> ENABLED transitions. */
+	if (connection->state == GB_CONNECTION_STATE_ENABLED_TX) {
+		if (!(connection->handler && rx))
+			return 0;
+
+		spin_lock_irq(&connection->lock);
+		connection->state = GB_CONNECTION_STATE_ENABLED;
+		spin_unlock_irq(&connection->lock);
+
+		return 0;
+	}
+
+	ret = gb_connection_hd_cport_enable(connection);
+	if (ret)
+		return ret;
+
+	ret = gb_connection_svc_connection_create(connection);
+	if (ret)
+		goto err_hd_cport_clear;
+
+	ret = gb_connection_hd_cport_connected(connection);
+	if (ret)
+		goto err_svc_connection_destroy;
+
+	spin_lock_irq(&connection->lock);
+	if (connection->handler && rx)
+		connection->state = GB_CONNECTION_STATE_ENABLED;
+	else
+		connection->state = GB_CONNECTION_STATE_ENABLED_TX;
+	spin_unlock_irq(&connection->lock);
+
+	ret = gb_connection_control_connected(connection);
+	if (ret)
+		goto err_control_disconnecting;
+
+	return 0;
+
+err_control_disconnecting:
+	spin_lock_irq(&connection->lock);
+	connection->state = GB_CONNECTION_STATE_DISCONNECTING;
+	gb_connection_cancel_operations(connection, -ESHUTDOWN);
+	spin_unlock_irq(&connection->lock);
+
+	/* Transmit queue should already be empty. */
+	gb_connection_hd_cport_flush(connection);
+
+	gb_connection_control_disconnecting(connection);
+	gb_connection_cport_shutdown_phase_1(connection);
+	gb_connection_hd_cport_quiesce(connection);
+	gb_connection_cport_shutdown_phase_2(connection);
+	gb_connection_control_disconnected(connection);
+	connection->state = GB_CONNECTION_STATE_DISABLED;
+err_svc_connection_destroy:
+	gb_connection_svc_connection_destroy(conne