280 lines
7.0 KiB
C
280 lines
7.0 KiB
C
/*
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* Greybus connections
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*
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* Copyright 2014 Google Inc.
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* Copyright 2014 Linaro Ltd.
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*
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* Released under the GPLv2 only.
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*/
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#include "greybus.h"
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static DEFINE_SPINLOCK(gb_connections_lock);
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/* This is only used at initialization time; no locking is required. */
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static struct gb_connection *
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gb_connection_intf_find(struct greybus_host_device *hd, u16 cport_id)
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{
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struct gb_connection *connection;
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list_for_each_entry(connection, &hd->connections, hd_links)
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if (connection->intf_cport_id == cport_id)
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return connection;
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return NULL;
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}
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static struct gb_connection *
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gb_connection_hd_find(struct greybus_host_device *hd, u16 cport_id)
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{
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struct gb_connection *connection;
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unsigned long flags;
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spin_lock_irqsave(&gb_connections_lock, flags);
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list_for_each_entry(connection, &hd->connections, hd_links)
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if (connection->hd_cport_id == cport_id)
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goto found;
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connection = NULL;
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found:
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spin_unlock_irqrestore(&gb_connections_lock, flags);
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return connection;
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}
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/*
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* Callback from the host driver to let us know that data has been
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* received on the bundle.
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*/
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void greybus_data_rcvd(struct greybus_host_device *hd, u16 cport_id,
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u8 *data, size_t length)
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{
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struct gb_connection *connection;
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connection = gb_connection_hd_find(hd, cport_id);
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if (!connection) {
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dev_err(hd->parent,
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"nonexistent connection (%zu bytes dropped)\n", length);
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return;
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}
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gb_connection_recv(connection, data, length);
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}
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EXPORT_SYMBOL_GPL(greybus_data_rcvd);
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static ssize_t state_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct gb_connection *connection = to_gb_connection(dev);
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return sprintf(buf, "%d\n", connection->state);
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}
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static DEVICE_ATTR_RO(state);
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static ssize_t
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protocol_id_show(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct gb_connection *connection = to_gb_connection(dev);
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return sprintf(buf, "%d\n", connection->protocol->id);
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}
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static DEVICE_ATTR_RO(protocol_id);
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static struct attribute *connection_attrs[] = {
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&dev_attr_state.attr,
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&dev_attr_protocol_id.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(connection);
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static void gb_connection_release(struct device *dev)
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{
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struct gb_connection *connection = to_gb_connection(dev);
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kfree(connection);
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}
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struct device_type greybus_connection_type = {
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.name = "greybus_connection",
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.release = gb_connection_release,
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};
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void gb_connection_bind_protocol(struct gb_connection *connection)
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{
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struct gb_bundle *bundle;
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struct gb_protocol *protocol;
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/* If we already have a protocol bound here, just return */
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if (connection->protocol)
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return;
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protocol = gb_protocol_get(connection->protocol_id,
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connection->major,
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connection->minor);
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if (!protocol)
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return;
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connection->protocol = protocol;
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/*
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* If we have a valid device_id for the bundle, then we have an active
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* device, so bring up the connection at the same time.
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* */
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bundle = connection->bundle;
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if (bundle->device_id != GB_DEVICE_ID_BAD)
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gb_connection_init(connection);
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}
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/*
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* Set up a Greybus connection, representing the bidirectional link
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* between a CPort on a (local) Greybus host device and a CPort on
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* another Greybus module.
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*
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* A connection also maintains the state of operations sent over the
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* connection.
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*
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* Returns a pointer to the new connection if successful, or a null
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* pointer otherwise.
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*/
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struct gb_connection *gb_connection_create(struct gb_bundle *bundle,
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u16 cport_id, u8 protocol_id)
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{
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struct gb_connection *connection;
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struct greybus_host_device *hd = bundle->intf->hd;
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struct ida *id_map = &hd->cport_id_map;
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int retval;
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u8 major = 0;
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u8 minor = 1;
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/*
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* If a manifest tries to reuse a cport, reject it. We
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* initialize connections serially so we don't need to worry
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* about holding the connection lock.
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*/
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if (gb_connection_intf_find(hd, cport_id)) {
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pr_err("duplicate interface cport id 0x%04hx\n", cport_id);
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return NULL;
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}
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connection = kzalloc(sizeof(*connection), GFP_KERNEL);
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if (!connection)
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return NULL;
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retval = ida_simple_get(id_map, 0, CPORT_ID_MAX, GFP_KERNEL);
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if (retval < 0) {
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kfree(connection);
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return NULL;
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}
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connection->hd_cport_id = (u16)retval;
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connection->intf_cport_id = cport_id;
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connection->hd = hd;
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connection->protocol_id = protocol_id;
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connection->major = major;
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connection->minor = minor;
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connection->bundle = bundle;
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connection->state = GB_CONNECTION_STATE_DISABLED;
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connection->dev.parent = &bundle->dev;
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connection->dev.bus = &greybus_bus_type;
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connection->dev.type = &greybus_connection_type;
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connection->dev.groups = connection_groups;
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device_initialize(&connection->dev);
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dev_set_name(&connection->dev, "%s:%d",
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dev_name(&bundle->dev), cport_id);
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retval = device_add(&connection->dev);
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if (retval) {
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struct ida *id_map = &connection->hd->cport_id_map;
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ida_simple_remove(id_map, connection->hd_cport_id);
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connection->hd_cport_id = CPORT_ID_BAD;
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put_device(&connection->dev);
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pr_err("failed to add connection device for cport 0x%04hx\n",
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cport_id);
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return NULL;
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}
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/* XXX Will have to establish connections to get version */
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gb_connection_bind_protocol(connection);
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if (!connection->protocol)
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dev_warn(&bundle->dev,
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"protocol 0x%02hhx handler not found\n", protocol_id);
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spin_lock_irq(&gb_connections_lock);
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list_add(&connection->hd_links, &hd->connections);
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list_add(&connection->bundle_links, &bundle->connections);
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spin_unlock_irq(&gb_connections_lock);
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atomic_set(&connection->op_cycle, 0);
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INIT_LIST_HEAD(&connection->operations);
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return connection;
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}
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/*
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* Tear down a previously set up connection.
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*/
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void gb_connection_destroy(struct gb_connection *connection)
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{
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struct gb_operation *operation;
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struct gb_operation *next;
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struct ida *id_map;
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if (WARN_ON(!connection))
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return;
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/* XXX Need to wait for any outstanding requests to complete */
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if (WARN_ON(!list_empty(&connection->operations))) {
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list_for_each_entry_safe(operation, next,
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&connection->operations, links)
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gb_operation_cancel(operation, -ESHUTDOWN);
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}
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spin_lock_irq(&gb_connections_lock);
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list_del(&connection->bundle_links);
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list_del(&connection->hd_links);
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spin_unlock_irq(&gb_connections_lock);
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gb_protocol_put(connection->protocol);
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connection->protocol = NULL;
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id_map = &connection->hd->cport_id_map;
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ida_simple_remove(id_map, connection->hd_cport_id);
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connection->hd_cport_id = CPORT_ID_BAD;
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device_unregister(&connection->dev);
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}
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int gb_connection_init(struct gb_connection *connection)
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{
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int ret;
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if (!connection->protocol) {
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dev_warn(&connection->dev, "init without protocol.\n");
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return 0;
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}
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/* Need to enable the connection to initialize it */
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connection->state = GB_CONNECTION_STATE_ENABLED;
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ret = connection->protocol->connection_init(connection);
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if (ret)
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connection->state = GB_CONNECTION_STATE_ERROR;
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return ret;
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}
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void gb_connection_exit(struct gb_connection *connection)
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{
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if (!connection->protocol) {
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dev_warn(&connection->dev, "exit without protocol.\n");
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return;
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}
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if (connection->state != GB_CONNECTION_STATE_ENABLED)
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return;
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connection->state = GB_CONNECTION_STATE_DESTROYING;
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connection->protocol->connection_exit(connection);
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}
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