--- /dev/null
+/*
+ * Ultra Wide Band
+ * Neighborhood Management Daemon
+ *
+ * Copyright (C) 2005-2006 Intel Corporation
+ * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ *
+ * This daemon takes care of maintaing information that describes the
+ * UWB neighborhood that the radios in this machine can see. It also
+ * keeps a tab of which devices are visible, makes sure each HC sits
+ * on a different channel to avoid interfering, etc.
+ *
+ * Different drivers (radio controller, device, any API in general)
+ * communicate with this daemon through an event queue. Daemon wakes
+ * up, takes a list of events and handles them one by one; handling
+ * function is extracted from a table based on the event's type and
+ * subtype. Events are freed only if the handling function says so.
+ *
+ * . Lock protecting the event list has to be an spinlock and locked
+ * with IRQSAVE because it might be called from an interrupt
+ * context (ie: when events arrive and the notification drops
+ * down from the ISR).
+ *
+ * . UWB radio controller drivers queue events to the daemon using
+ * uwbd_event_queue(). They just get the event, chew it to make it
+ * look like UWBD likes it and pass it in a buffer allocated with
+ * uwb_event_alloc().
+ *
+ * EVENTS
+ *
+ * Events have a type, a subtype, a length, some other stuff and the
+ * data blob, which depends on the event. The header is 'struct
+ * uwb_event'; for payloads, see 'struct uwbd_evt_*'.
+ *
+ * EVENT HANDLER TABLES
+ *
+ * To find a handling function for an event, the type is used to index
+ * a subtype-table in the type-table. The subtype-table is indexed
+ * with the subtype to get the function that handles the event. Start
+ * with the main type-table 'uwbd_evt_type_handler'.
+ *
+ * DEVICES
+ *
+ * Devices are created when a bunch of beacons have been received and
+ * it is stablished that the device has stable radio presence. CREATED
+ * only, not configured. Devices are ONLY configured when an
+ * Application-Specific IE Probe is receieved, in which the device
+ * declares which Protocol ID it groks. Then the device is CONFIGURED
+ * (and the driver->probe() stuff of the device model is invoked).
+ *
+ * Devices are considered disconnected when a certain number of
+ * beacons are not received in an amount of time.
+ *
+ * Handler functions are called normally uwbd_evt_handle_*().
+ */
+#include <linux/kthread.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/freezer.h>
+
+#include "uwb-internal.h"
+
+/*
+ * UWBD Event handler function signature
+ *
+ * Return !0 if the event needs not to be freed (ie the handler
+ * takes/took care of it). 0 means the daemon code will free the
+ * event.
+ *
+ * @evt->rc is already referenced and guaranteed to exist. See
+ * uwb_evt_handle().
+ */
+typedef int (*uwbd_evt_handler_f)(struct uwb_event *);
+
+/**
+ * Properties of a UWBD event
+ *
+ * @handler: the function that will handle this event
+ * @name: text name of event
+ */
+struct uwbd_event {
+ uwbd_evt_handler_f handler;
+ const char *name;
+};
+
+/* Table of handlers for and properties of the UWBD Radio Control Events */
+static struct uwbd_event uwbd_urc_events[] = {
+ [UWB_RC_EVT_IE_RCV] = {
+ .handler = uwbd_evt_handle_rc_ie_rcv,
+ .name = "IE_RECEIVED"
+ },
+ [UWB_RC_EVT_BEACON] = {
+ .handler = uwbd_evt_handle_rc_beacon,
+ .name = "BEACON_RECEIVED"
+ },
+ [UWB_RC_EVT_BEACON_SIZE] = {
+ .handler = uwbd_evt_handle_rc_beacon_size,
+ .name = "BEACON_SIZE_CHANGE"
+ },
+ [UWB_RC_EVT_BPOIE_CHANGE] = {
+ .handler = uwbd_evt_handle_rc_bpoie_change,
+ .name = "BPOIE_CHANGE"
+ },
+ [UWB_RC_EVT_BP_SLOT_CHANGE] = {
+ .handler = uwbd_evt_handle_rc_bp_slot_change,
+ .name = "BP_SLOT_CHANGE"
+ },
+ [UWB_RC_EVT_DRP_AVAIL] = {
+ .handler = uwbd_evt_handle_rc_drp_avail,
+ .name = "DRP_AVAILABILITY_CHANGE"
+ },
+ [UWB_RC_EVT_DRP] = {
+ .handler = uwbd_evt_handle_rc_drp,
+ .name = "DRP"
+ },
+ [UWB_RC_EVT_DEV_ADDR_CONFLICT] = {
+ .handler = uwbd_evt_handle_rc_dev_addr_conflict,
+ .name = "DEV_ADDR_CONFLICT",
+ },
+};
+
+
+
+struct uwbd_evt_type_handler {
+ const char *name;
+ struct uwbd_event *uwbd_events;
+ size_t size;
+};
+
+/* Table of handlers for each UWBD Event type. */
+static struct uwbd_evt_type_handler uwbd_urc_evt_type_handlers[] = {
+ [UWB_RC_CET_GENERAL] = {
+ .name = "URC",
+ .uwbd_events = uwbd_urc_events,
+ .size = ARRAY_SIZE(uwbd_urc_events),
+ },
+};
+
+static const struct uwbd_event uwbd_message_handlers[] = {
+ [UWB_EVT_MSG_RESET] = {
+ .handler = uwbd_msg_handle_reset,
+ .name = "reset",
+ },
+};
+
+/*
+ * Handle an URC event passed to the UWB Daemon
+ *
+ * @evt: the event to handle
+ * @returns: 0 if the event can be kfreed, !0 on the contrary
+ * (somebody else took ownership) [coincidentally, returning
+ * a <0 errno code will free it :)].
+ *
+ * Looks up the two indirection tables (one for the type, one for the
+ * subtype) to decide which function handles it and then calls the
+ * handler.
+ *
+ * The event structure passed to the event handler has the radio
+ * controller in @evt->rc referenced. The reference will be dropped
+ * once the handler returns, so if it needs it for longer (async),
+ * it'll need to take another one.
+ */
+static
+int uwbd_event_handle_urc(struct uwb_event *evt)
+{
+ int result = -EINVAL;
+ struct uwbd_evt_type_handler *type_table;
+ uwbd_evt_handler_f handler;
+ u8 type, context;
+ u16 event;
+
+ type = evt->notif.rceb->bEventType;
+ event = le16_to_cpu(evt->notif.rceb->wEvent);
+ context = evt->notif.rceb->bEventContext;
+
+ if (type >= ARRAY_SIZE(uwbd_urc_evt_type_handlers))
+ goto out;
+ type_table = &uwbd_urc_evt_type_handlers[type];
+ if (type_table->uwbd_events == NULL)
+ goto out;
+ if (event >= type_table->size)
+ goto out;
+ handler = type_table->uwbd_events[event].handler;
+ if (handler == NULL)
+ goto out;
+
+ result = (*handler)(evt);
+out:
+ if (result < 0)
+ dev_err(&evt->rc->uwb_dev.dev,
+ "UWBD: event 0x%02x/%04x/%02x, handling failed: %d\n",
+ type, event, context, result);
+ return result;
+}
+
+static void uwbd_event_handle_message(struct uwb_event *evt)
+{
+ struct uwb_rc *rc;
+ int result;
+
+ rc = evt->rc;
+
+ if (evt->message < 0 || evt->message >= ARRAY_SIZE(uwbd_message_handlers)) {
+ dev_err(&rc->uwb_dev.dev, "UWBD: invalid message type %d\n", evt->message);
+ return;
+ }
+
+ result = uwbd_message_handlers[evt->message].handler(evt);
+ if (result < 0)
+ dev_err(&rc->uwb_dev.dev, "UWBD: '%s' message failed: %d\n",
+ uwbd_message_handlers[evt->message].name, result);
+}
+
+static void uwbd_event_handle(struct uwb_event *evt)
+{
+ struct uwb_rc *rc;
+ int should_keep;
+
+ rc = evt->rc;
+
+ if (rc->ready) {
+ switch (evt->type) {
+ case UWB_EVT_TYPE_NOTIF:
+ should_keep = uwbd_event_handle_urc(evt);
+ if (should_keep <= 0)
+ kfree(evt->notif.rceb);
+ break;
+ case UWB_EVT_TYPE_MSG:
+ uwbd_event_handle_message(evt);
+ break;
+ default:
+ dev_err(&rc->uwb_dev.dev, "UWBD: invalid event type %d\n", evt->type);
+ break;
+ }
+ }
+
+ __uwb_rc_put(rc); /* for the __uwb_rc_get() in uwb_rc_notif_cb() */
+}
+
+/**
+ * UWB Daemon
+ *
+ * Listens to all UWB notifications and takes care to track the state
+ * of the UWB neighbourhood for the kernel. When we do a run, we
+ * spinlock, move the list to a private copy and release the
+ * lock. Hold it as little as possible. Not a conflict: it is
+ * guaranteed we own the events in the private list.
+ *
+ * FIXME: should change so we don't have a 1HZ timer all the time, but
+ * only if there are devices.
+ */
+static int uwbd(void *param)
+{
+ struct uwb_rc *rc = param;
+ unsigned long flags;
+ struct uwb_event *evt;
+ int should_stop = 0;
+
+ while (1) {
+ wait_event_interruptible_timeout(
+ rc->uwbd.wq,
+ !list_empty(&rc->uwbd.event_list)
+ || (should_stop = kthread_should_stop()),
+ HZ);
+ if (should_stop)
+ break;
+ try_to_freeze();
+
+ spin_lock_irqsave(&rc->uwbd.event_list_lock, flags);
+ if (!list_empty(&rc->uwbd.event_list)) {
+ evt = list_first_entry(&rc->uwbd.event_list, struct uwb_event, list_node);
+ list_del(&evt->list_node);
+ } else
+ evt = NULL;
+ spin_unlock_irqrestore(&rc->uwbd.event_list_lock, flags);
+
+ if (evt) {
+ uwbd_event_handle(evt);
+ kfree(evt);
+ }
+
+ uwb_beca_purge(rc); /* Purge devices that left */
+ }
+ return 0;
+}
+
+
+/** Start the UWB daemon */
+void uwbd_start(struct uwb_rc *rc)
+{
+ rc->uwbd.task = kthread_run(uwbd, rc, "uwbd");
+ if (rc->uwbd.task == NULL)
+ printk(KERN_ERR "UWB: Cannot start management daemon; "
+ "UWB won't work\n");
+ else
+ rc->uwbd.pid = rc->uwbd.task->pid;
+}
+
+/* Stop the UWB daemon and free any unprocessed events */
+void uwbd_stop(struct uwb_rc *rc)
+{
+ kthread_stop(rc->uwbd.task);
+ uwbd_flush(rc);
+}
+
+/*
+ * Queue an event for the management daemon
+ *
+ * When some lower layer receives an event, it uses this function to
+ * push it forward to the UWB daemon.
+ *
+ * Once you pass the event, you don't own it any more, but the daemon
+ * does. It will uwb_event_free() it when done, so make sure you
+ * uwb_event_alloc()ed it or bad things will happen.
+ *
+ * If the daemon is not running, we just free the event.
+ */
+void uwbd_event_queue(struct uwb_event *evt)
+{
+ struct uwb_rc *rc = evt->rc;
+ unsigned long flags;
+
+ spin_lock_irqsave(&rc->uwbd.event_list_lock, flags);
+ if (rc->uwbd.pid != 0) {
+ list_add(&evt->list_node, &rc->uwbd.event_list);
+ wake_up_all(&rc->uwbd.wq);
+ } else {
+ __uwb_rc_put(evt->rc);
+ if (evt->type == UWB_EVT_TYPE_NOTIF)
+ kfree(evt->notif.rceb);
+ kfree(evt);
+ }
+ spin_unlock_irqrestore(&rc->uwbd.event_list_lock, flags);
+ return;
+}
+
+void uwbd_flush(struct uwb_rc *rc)
+{
+ struct uwb_event *evt, *nxt;
+
+ spin_lock_irq(&rc->uwbd.event_list_lock);
+ list_for_each_entry_safe(evt, nxt, &rc->uwbd.event_list, list_node) {
+ if (evt->rc == rc) {
+ __uwb_rc_put(rc);
+ list_del(&evt->list_node);
+ if (evt->type == UWB_EVT_TYPE_NOTIF)
+ kfree(evt->notif.rceb);
+ kfree(evt);
+ }
+ }
+ spin_unlock_irq(&rc->uwbd.event_list_lock);
+}
Code Review / kvmfornfv.git / blobdiff