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|
/*
* Greybus connections
*
* Copyright 2014 Google Inc.
* Copyright 2014 Linaro Ltd.
*
* Released under the GPLv2 only.
*/
#include <linux/workqueue.h>
#include "greybus.h"
#define GB_CONNECTION_TS_KFIFO_ELEMENTS 2
#define GB_CONNECTION_TS_KFIFO_LEN \
(GB_CONNECTION_TS_KFIFO_ELEMENTS * sizeof(struct timeval))
static DEFINE_SPINLOCK(gb_connections_lock);
/* This is only used at initialization time; no locking is required. */
static struct gb_connection *
gb_connection_intf_find(struct gb_interface *intf, u16 cport_id)
{
struct greybus_host_device *hd = intf->hd;
struct gb_connection *connection;
list_for_each_entry(connection, &hd->connections, hd_links)
if (connection->bundle->intf == intf &&
connection->intf_cport_id == cport_id)
return connection;
return NULL;
}
static struct gb_connection *
gb_connection_hd_find(struct greybus_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)
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 greybus_host_device *hd, u16 cport_id,
u8 *data, size_t length)
{
struct gb_connection *connection;
connection = gb_connection_hd_find(hd, cport_id);
if (!connection) {
dev_err(hd->parent,
"nonexistent connection (%zu bytes dropped)\n", length);
return;
}
gb_connection_recv(connection, data, length);
}
EXPORT_SYMBOL_GPL(greybus_data_rcvd);
void gb_connection_push_timestamp(struct gb_connection *connection)
{
struct timeval tv;
do_gettimeofday(&tv);
kfifo_in_locked(&connection->ts_kfifo, (void *)&tv,
sizeof(struct timeval), &connection->lock);
}
EXPORT_SYMBOL_GPL(gb_connection_push_timestamp);
int gb_connection_pop_timestamp(struct gb_connection *connection,
struct timeval *tv)
{
int retval;
if (!kfifo_len(&connection->ts_kfifo))
return -ENOMEM;
retval = kfifo_out_locked(&connection->ts_kfifo, (void *)tv,
sizeof(*tv), &connection->lock);
return retval;
}
EXPORT_SYMBOL_GPL(gb_connection_pop_timestamp);
static ssize_t state_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct gb_connection *connection = to_gb_connection(dev);
enum gb_connection_state state;
spin_lock_irq(&connection->lock);
state = connection->state;
spin_unlock_irq(&connection->lock);
return sprintf(buf, "%d\n", state);
}
static DEVICE_ATTR_RO(state);
static ssize_t
protocol_id_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct gb_connection *connection = to_gb_connection(dev);
if (connection->protocol)
return sprintf(buf, "%d\n", connection->protocol->id);
else
return -EINVAL;
}
static DEVICE_ATTR_RO(protocol_id);
static struct attribute *connection_attrs[] = {
&dev_attr_state.attr,
&dev_attr_protocol_id.attr,
NULL,
};
ATTRIBUTE_GROUPS(connection);
static void gb_connection_release(struct device *dev)
{
struct gb_connection *connection = to_gb_connection(dev);
destroy_workqueue(connection->wq);
kfifo_free(&connection->ts_kfifo);
kfree(connection);
}
struct device_type greybus_connection_type = {
.name = "greybus_connection",
.release = gb_connection_release,
};
int svc_update_connection(struct gb_interface *intf,
struct gb_connection *connection)
{
struct gb_bundle *bundle;
bundle = gb_bundle_create(intf, GB_SVC_BUNDLE_ID, GREYBUS_CLASS_SVC);
if (!bundle)
return -EINVAL;
device_del(&connection->dev);
connection->bundle = bundle;
connection->dev.parent = &bundle->dev;
dev_set_name(&connection->dev, "%s:%d", dev_name(&bundle->dev),
GB_SVC_CPORT_ID);
WARN_ON(device_add(&connection->dev));
spin_lock_irq(&gb_connections_lock);
list_add(&connection->bundle_links, &bundle->connections);
spin_unlock_irq(&gb_connections_lock);
return 0;
}
/*
* Set up a Greybus connection, representing the bidirectional link
* between a CPort on a (local) Greybus host device and a CPort on
* another Greybus module.
*
* A connection also maintains the state of operations sent over the
* connection.
*
* Returns a pointer to the new connection if successful, or a null
* pointer otherwise.
*/
struct gb_connection *
gb_connection_create_range(struct greybus_host_device *hd,
struct gb_bundle *bundle, struct device *parent,
u16 cport_id, u8 protocol_id, u32 ida_start,
u32 ida_end)
{
struct gb_connection *connection;
struct ida *id_map = &hd->cport_id_map;
int hd_cport_id;
int retval;
u8 major = 0;
u8 minor = 1;
/*
* If a manifest tries to reuse a cport, reject it. We
* initialize connections serially so we don't need to worry
* about holding the connection lock.
*/
if (bundle && gb_connection_intf_find(bundle->intf, cport_id)) {
pr_err("duplicate interface cport id 0x%04hx\n", cport_id);
return NULL;
}
hd_cport_id = ida_simple_get(id_map, ida_start, ida_end, GFP_KERNEL);
if (hd_cport_id < 0)
return NULL;
connection = kzalloc(sizeof(*connection), GFP_KERNEL);
if (!connection)
goto err_remove_ida;
connection->hd_cport_id = hd_cport_id;
connection->intf_cport_id = cport_id;
connection->hd = hd;
connection->protocol_id = protocol_id;
connection->major = major;
connection->minor = minor;
connection->bundle = bundle;
connection->state = GB_CONNECTION_STATE_DISABLED;
atomic_set(&connection->op_cycle, 0);
spin_lock_init(&connection->lock);
INIT_LIST_HEAD(&connection->operations);
connection->wq = alloc_workqueue("%s:%d", WQ_UNBOUND, 1,
dev_name(parent), cport_id);
if (!connection->wq)
goto err_free_connection;
if (kfifo_alloc(&connection->ts_kfifo, GB_CONNECTION_TS_KFIFO_LEN,
GFP_KERNEL))
goto err_destroy_wq;
connection->dev.parent = parent;
connection->dev.bus = &greybus_bus_type;
connection->dev.type = &greybus_connection_type;
connection->dev.groups = connection_groups;
device_initialize(&connection->dev);
dev_set_name(&connection->dev, "%s:%d",
dev_name(parent), cport_id);
retval = device_add(&connection->dev);
if (retval) {
connection->hd_cport_id = CPORT_ID_BAD;
put_device(&connection->dev);
pr_err("failed to add connection device for cport 0x%04hx\n",
cport_id);
goto err_remove_ida;
}
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);
gb_connection_bind_protocol(connection);
if (!connection->protocol)
dev_warn(&connection->dev,
"protocol 0x%02hhx handler not found\n", protocol_id);
return connection;
err_destroy_wq:
destroy_workqueue(connection->wq);
err_free_connection:
kfree(connection);
err_remove_ida:
ida_simple_remove(id_map, hd_cport_id);
return NULL;
}
struct gb_connection *gb_connection_create(struct gb_bundle *bundle,
u16 cport_id, u8 protocol_id)
{
return gb_connection_create_range(bundle->intf->hd, bundle,
&bundle->dev, cport_id, protocol_id,
0, bundle->intf->hd->num_cports - 1);
}
/*
* Cancel all active operations on a connection.
*
* Should only be called during connection tear down.
*/
static void gb_connection_cancel_operations(struct gb_connection *connection,
int errno)
{
struct gb_operation *operation;
spin_lock_irq(&connection->lock);
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);
}
spin_unlock_irq(&connection->lock);
}
static void gb_connection_disconnected(struct gb_connection *connection)
{
struct gb_control *control;
int cport_id = connection->intf_cport_id;
int ret;
/*
* Inform Interface about In-active CPorts. We don't need to do this
* operation for control cport.
*/
if ((cport_id == GB_CONTROL_CPORT_ID) ||
(connection->hd_cport_id == GB_SVC_CPORT_ID))
return;
control = connection->bundle->intf->control;
ret = gb_control_disconnected_operation(control, cport_id);
if (ret)
dev_warn(&connection->dev,
"Failed to disconnect CPort-%d (%d)\n", cport_id, ret);
}
static int gb_connection_init(struct gb_connection *connection)
{
int cport_id = connection->intf_cport_id;
struct greybus_host_device *hd = connection->hd;
int ret;
/*
* Request the SVC to create a connection from AP's cport to interface's
* cport.
*/
if (connection->hd_cport_id != GB_SVC_CPORT_ID) {
ret = gb_svc_connection_create(hd->svc,
hd->endo->ap_intf_id, connection->hd_cport_id,
connection->bundle->intf->interface_id,
cport_id);
if (ret) {
dev_err(&connection->dev,
"%s: Failed to create svc connection (%d)\n",
__func__, ret);
return ret;
}
if (hd->driver->connection_create)
hd->driver->connection_create(connection);
}
/*
* Inform Interface about Active CPorts. We don't need to do this
* operation for control cport.
*/
if (cport_id != GB_CONTROL_CPORT_ID &&
connection->hd_cport_id != GB_SVC_CPORT_ID) {
struct gb_control *control = connection->bundle->intf->control;
ret = gb_control_connected_operation(control, cport_id);
if (ret) {
dev_err(&connection->dev,
"Failed to connect CPort-%d (%d)\n",
cport_id, ret);
return ret;
}
}
/* Need to enable the connection to initialize it */
spin_lock_irq(&connection->lock);
connection->state = GB_CONNECTION_STATE_ENABLED;
spin_unlock_irq(&connection->lock);
/*
* Request protocol version supported by the module. We don't need to do
* this for SVC as that is initiated by the SVC.
*/
if (connection->hd_cport_id != GB_SVC_CPORT_ID) {
ret = gb_protocol_get_version(connection);
if (ret) {
dev_err(&connection->dev,
"Failed to get version CPort-%d (%d)\n",
cport_id, ret);
goto disconnect;
}
}
ret = connection->protocol->connection_init(connection);
if (!ret)
return 0;
disconnect:
spin_lock_irq(&connection->lock);
connection->state = GB_CONNECTION_STATE_ERROR;
spin_unlock_irq(&connection->lock);
gb_connection_disconnected(connection);
return ret;
}
static void gb_connection_exit(struct gb_connection *connection)
{
if (!connection->protocol)
return;
spin_lock_irq(&connection->lock);
if (connection->state != GB_CONNECTION_STATE_ENABLED) {
spin_unlock_irq(&connection->lock);
return;
}
connection->state = GB_CONNECTION_STATE_DESTROYING;
spin_unlock_irq(&connection->lock);
gb_connection_cancel_operations(connection, -ESHUTDOWN);
connection->protocol->connection_exit(connection);
gb_connection_disconnected(connection);
}
/*
* Tear down a previously set up connection.
*/
void gb_connection_destroy(struct gb_connection *connection)
{
struct ida *id_map;
if (WARN_ON(!connection))
return;
gb_connection_exit(connection);
spin_lock_irq(&gb_connections_lock);
list_del(&connection->bundle_links);
list_del(&connection->hd_links);
spin_unlock_irq(&gb_connections_lock);
if (connection->hd->driver->connection_destroy)
connection->hd->driver->connection_destroy(connection);
if (connection->protocol)
gb_protocol_put(connection->protocol);
connection->protocol = NULL;
id_map = &connection->hd->cport_id_map;
ida_simple_remove(id_map, connection->hd_cport_id);
connection->hd_cport_id = CPORT_ID_BAD;
device_unregister(&connection->dev);
}
void gb_hd_connections_exit(struct greybus_host_device *hd)
{
struct gb_connection *connection;
list_for_each_entry(connection, &hd->connections, hd_links)
gb_connection_destroy(connection);
}
int gb_connection_bind_protocol(struct gb_connection *connection)
{
struct gb_protocol *protocol;
int ret;
/* If we already have a protocol bound here, just return */
if (connection->protocol)
return 0;
protocol = gb_protocol_get(connection->protocol_id,
connection->major,
connection->minor);
if (!protocol)
return 0;
connection->protocol = protocol;
/*
* If we have a valid device_id for the interface block, then we have an
* active device, so bring up the connection at the same time.
*/
if ((!connection->bundle &&
connection->hd_cport_id == GB_SVC_CPORT_ID) ||
connection->bundle->intf->device_id != GB_DEVICE_ID_BAD) {
ret = gb_connection_init(connection);
if (ret) {
gb_protocol_put(protocol);
connection->protocol = NULL;
return ret;
}
}
return 0;
}
|