+
+/*
+ * Reorder queue data stored on skb->cb while the skb is queued in the
+ * reorder queues.
+ */
+struct i2400m_roq_data {
+ unsigned sn; /* Serial number for the skb */
+ enum i2400m_cs cs; /* packet type for the skb */
+};
+
+
+/*
+ * ReOrder Queue
+ *
+ * @ws: Window Start; sequence number where the current window start
+ * is for this queue
+ * @queue: the skb queue itself
+ * @log: circular ring buffer used to log information about the
+ * reorder process in this queue that can be displayed in case of
+ * error to help diagnose it.
+ *
+ * This is the head for a list of skbs. In the skb->cb member of the
+ * skb when queued here contains a 'struct i2400m_roq_data' were we
+ * store the sequence number (sn) and the cs (packet type) coming from
+ * the RX payload header from the device.
+ */
+struct i2400m_roq
+{
+ unsigned ws;
+ struct sk_buff_head queue;
+ struct i2400m_roq_log *log;
+};
+
+
+static
+void __i2400m_roq_init(struct i2400m_roq *roq)
+{
+ roq->ws = 0;
+ skb_queue_head_init(&roq->queue);
+}
+
+
+static
+unsigned __i2400m_roq_index(struct i2400m *i2400m, struct i2400m_roq *roq)
+{
+ return ((unsigned long) roq - (unsigned long) i2400m->rx_roq)
+ / sizeof(*roq);
+}
+
+
+/*
+ * Normalize a sequence number based on the queue's window start
+ *
+ * nsn = (sn - ws) % 2048
+ *
+ * Note that if @sn < @roq->ws, we still need a positive number; %'s
+ * sign is implementation specific, so we normalize it by adding 2048
+ * to bring it to be positive.
+ */
+static
+unsigned __i2400m_roq_nsn(struct i2400m_roq *roq, unsigned sn)
+{
+ int r;
+ r = ((int) sn - (int) roq->ws) % 2048;
+ if (r < 0)
+ r += 2048;
+ return r;
+}
+
+
+/*
+ * Circular buffer to keep the last N reorder operations
+ *
+ * In case something fails, dumb then to try to come up with what
+ * happened.
+ */
+enum {
+ I2400M_ROQ_LOG_LENGTH = 32,
+};
+
+struct i2400m_roq_log {
+ struct i2400m_roq_log_entry {
+ enum i2400m_ro_type type;
+ unsigned ws, count, sn, nsn, new_ws;
+ } entry[I2400M_ROQ_LOG_LENGTH];
+ unsigned in, out;
+};
+
+
+/* Print a log entry */
+static
+void i2400m_roq_log_entry_print(struct i2400m *i2400m, unsigned index,
+ unsigned e_index,
+ struct i2400m_roq_log_entry *e)
+{
+ struct device *dev = i2400m_dev(i2400m);
+
+ switch(e->type) {
+ case I2400M_RO_TYPE_RESET:
+ dev_err(dev, "q#%d reset ws %u cnt %u sn %u/%u"
+ " - new nws %u\n",
+ index, e->ws, e->count, e->sn, e->nsn, e->new_ws);
+ break;
+ case I2400M_RO_TYPE_PACKET:
+ dev_err(dev, "q#%d queue ws %u cnt %u sn %u/%u\n",
+ index, e->ws, e->count, e->sn, e->nsn);
+ break;
+ case I2400M_RO_TYPE_WS:
+ dev_err(dev, "q#%d update_ws ws %u cnt %u sn %u/%u"
+ " - new nws %u\n",
+ index, e->ws, e->count, e->sn, e->nsn, e->new_ws);
+ break;
+ case I2400M_RO_TYPE_PACKET_WS:
+ dev_err(dev, "q#%d queue_update_ws ws %u cnt %u sn %u/%u"
+ " - new nws %u\n",
+ index, e->ws, e->count, e->sn, e->nsn, e->new_ws);
+ break;
+ default:
+ dev_err(dev, "q#%d BUG? entry %u - unknown type %u\n",
+ index, e_index, e->type);
+ break;
+ }
+}
+
+
+static
+void i2400m_roq_log_add(struct i2400m *i2400m,
+ struct i2400m_roq *roq, enum i2400m_ro_type type,
+ unsigned ws, unsigned count, unsigned sn,
+ unsigned nsn, unsigned new_ws)
+{
+ struct i2400m_roq_log_entry *e;
+ unsigned cnt_idx;
+ int index = __i2400m_roq_index(i2400m, roq);
+
+ /* if we run out of space, we eat from the end */
+ if (roq->log->in - roq->log->out == I2400M_ROQ_LOG_LENGTH)
+ roq->log->out++;
+ cnt_idx = roq->log->in++ % I2400M_ROQ_LOG_LENGTH;
+ e = &roq->log->entry[cnt_idx];
+
+ e->type = type;
+ e->ws = ws;
+ e->count = count;
+ e->sn = sn;
+ e->nsn = nsn;
+ e->new_ws = new_ws;
+
+ if (d_test(1))
+ i2400m_roq_log_entry_print(i2400m, index, cnt_idx, e);
+}
+
+
+/* Dump all the entries in the FIFO and reinitialize it */
+static
+void i2400m_roq_log_dump(struct i2400m *i2400m, struct i2400m_roq *roq)
+{
+ unsigned cnt, cnt_idx;
+ struct i2400m_roq_log_entry *e;
+ int index = __i2400m_roq_index(i2400m, roq);
+
+ BUG_ON(roq->log->out > roq->log->in);
+ for (cnt = roq->log->out; cnt < roq->log->in; cnt++) {
+ cnt_idx = cnt % I2400M_ROQ_LOG_LENGTH;
+ e = &roq->log->entry[cnt_idx];
+ i2400m_roq_log_entry_print(i2400m, index, cnt_idx, e);
+ memset(e, 0, sizeof(*e));
+ }
+ roq->log->in = roq->log->out = 0;
+}
+
+
+/*
+ * Backbone for the queuing of an skb (by normalized sequence number)
+ *
+ * @i2400m: device descriptor
+ * @roq: reorder queue where to add
+ * @skb: the skb to add
+ * @sn: the sequence number of the skb
+ * @nsn: the normalized sequence number of the skb (pre-computed by the
+ * caller from the @sn and @roq->ws).
+ *
+ * We try first a couple of quick cases:
+ *
+ * - the queue is empty
+ * - the skb would be appended to the queue
+ *
+ * These will be the most common operations.
+ *
+ * If these fail, then we have to do a sorted insertion in the queue,
+ * which is the slowest path.
+ *
+ * We don't have to acquire a reference count as we are going to own it.
+ */
+static
+void __i2400m_roq_queue(struct i2400m *i2400m, struct i2400m_roq *roq,
+ struct sk_buff *skb, unsigned sn, unsigned nsn)
+{
+ struct device *dev = i2400m_dev(i2400m);
+ struct sk_buff *skb_itr;
+ struct i2400m_roq_data *roq_data_itr, *roq_data;
+ unsigned nsn_itr;
+
+ d_fnstart(4, dev, "(i2400m %p roq %p skb %p sn %u nsn %u)\n",
+ i2400m, roq, skb, sn, nsn);
+
+ roq_data = (struct i2400m_roq_data *) &skb->cb;
+ BUILD_BUG_ON(sizeof(*roq_data) > sizeof(skb->cb));
+ roq_data->sn = sn;
+ d_printf(3, dev, "ERX: roq %p [ws %u] nsn %d sn %u\n",
+ roq, roq->ws, nsn, roq_data->sn);
+
+ /* Queues will be empty on not-so-bad environments, so try
+ * that first */
+ if (skb_queue_empty(&roq->queue)) {
+ d_printf(2, dev, "ERX: roq %p - first one\n", roq);
+ __skb_queue_head(&roq->queue, skb);
+ goto out;
+ }
+ /* Now try append, as most of the operations will be that */
+ skb_itr = skb_peek_tail(&roq->queue);
+ roq_data_itr = (struct i2400m_roq_data *) &skb_itr->cb;
+ nsn_itr = __i2400m_roq_nsn(roq, roq_data_itr->sn);
+ /* NSN bounds assumed correct (checked when it was queued) */
+ if (nsn >= nsn_itr) {
+ d_printf(2, dev, "ERX: roq %p - appended after %p (nsn %d sn %u)\n",
+ roq, skb_itr, nsn_itr, roq_data_itr->sn);
+ __skb_queue_tail(&roq->queue, skb);
+ goto out;
+ }
+ /* None of the fast paths option worked. Iterate to find the
+ * right spot where to insert the packet; we know the queue is
+ * not empty, so we are not the first ones; we also know we
+ * are not going to be the last ones. The list is sorted, so
+ * we have to insert before the the first guy with an nsn_itr
+ * greater that our nsn. */
+ skb_queue_walk(&roq->queue, skb_itr) {
+ roq_data_itr = (struct i2400m_roq_data *) &skb_itr->cb;
+ nsn_itr = __i2400m_roq_nsn(roq, roq_data_itr->sn);
+ /* NSN bounds assumed correct (checked when it was queued) */
+ if (nsn_itr > nsn) {
+ d_printf(2, dev, "ERX: roq %p - queued before %p "
+ "(nsn %d sn %u)\n", roq, skb_itr, nsn_itr,
+ roq_data_itr->sn);
+ __skb_queue_before(&roq->queue, skb_itr, skb);
+ goto out;
+ }
+ }
+ /* If we get here, that is VERY bad -- print info to help
+ * diagnose and crash it */
+ dev_err(dev, "SW BUG? failed to insert packet\n");
+ dev_err(dev, "ERX: roq %p [ws %u] skb %p nsn %d sn %u\n",
+ roq, roq->ws, skb, nsn, roq_data->sn);
+ skb_queue_walk(&roq->queue, skb_itr) {
+ roq_data_itr = (struct i2400m_roq_data *) &skb_itr->cb;
+ nsn_itr = __i2400m_roq_nsn(roq, roq_data_itr->sn);
+ /* NSN bounds assumed correct (checked when it was queued) */
+ dev_err(dev, "ERX: roq %p skb_itr %p nsn %d sn %u\n",
+ roq, skb_itr, nsn_itr, roq_data_itr->sn);
+ }
+ BUG();
+out:
+ d_fnend(4, dev, "(i2400m %p roq %p skb %p sn %u nsn %d) = void\n",
+ i2400m, roq, skb, sn, nsn);
+ return;
+}
+
+
+/*
+ * Backbone for the update window start operation
+ *
+ * @i2400m: device descriptor
+ * @roq: Reorder queue
+ * @sn: New sequence number
+ *
+ * Updates the window start of a queue; when doing so, it must deliver
+ * to the networking stack all the queued skb's whose normalized
+ * sequence number is lower than the new normalized window start.
+ */
+static
+unsigned __i2400m_roq_update_ws(struct i2400m *i2400m, struct i2400m_roq *roq,
+ unsigned sn)
+{
+ struct device *dev = i2400m_dev(i2400m);
+ struct sk_buff *skb_itr, *tmp_itr;
+ struct i2400m_roq_data *roq_data_itr;
+ unsigned new_nws, nsn_itr;
+
+ new_nws = __i2400m_roq_nsn(roq, sn);
+ if (unlikely(new_nws >= 1024) && d_test(1)) {
+ dev_err(dev, "SW BUG? __update_ws new_nws %u (sn %u ws %u)\n",
+ new_nws, sn, roq->ws);
+ WARN_ON(1);
+ i2400m_roq_log_dump(i2400m, roq);
+ }
+ skb_queue_walk_safe(&roq->queue, skb_itr, tmp_itr) {
+ roq_data_itr = (struct i2400m_roq_data *) &skb_itr->cb;
+ nsn_itr = __i2400m_roq_nsn(roq, roq_data_itr->sn);
+ /* NSN bounds assumed correct (checked when it was queued) */
+ if (nsn_itr < new_nws) {
+ d_printf(2, dev, "ERX: roq %p - release skb %p "
+ "(nsn %u/%u new nws %u)\n",
+ roq, skb_itr, nsn_itr, roq_data_itr->sn,
+ new_nws);
+ __skb_unlink(skb_itr, &roq->queue);
+ i2400m_net_erx(i2400m, skb_itr, roq_data_itr->cs);
+ }
+ else
+ break; /* rest of packets all nsn_itr > nws */
+ }
+ roq->ws = sn;
+ return new_nws;
+}
+
+
+/*
+ * Reset a queue
+ *
+ * @i2400m: device descriptor
+ * @cin: Queue Index
+ *
+ * Deliver all the packets and reset the window-start to zero. Name is
+ * kind of misleading.
+ */
+static
+void i2400m_roq_reset(struct i2400m *i2400m, struct i2400m_roq *roq)
+{
+ struct device *dev = i2400m_dev(i2400m);
+ struct sk_buff *skb_itr, *tmp_itr;
+ struct i2400m_roq_data *roq_data_itr;
+
+ d_fnstart(2, dev, "(i2400m %p roq %p)\n", i2400m, roq);
+ i2400m_roq_log_add(i2400m, roq, I2400M_RO_TYPE_RESET,
+ roq->ws, skb_queue_len(&roq->queue),
+ ~0, ~0, 0);
+ skb_queue_walk_safe(&roq->queue, skb_itr, tmp_itr) {
+ roq_data_itr = (struct i2400m_roq_data *) &skb_itr->cb;
+ d_printf(2, dev, "ERX: roq %p - release skb %p (sn %u)\n",
+ roq, skb_itr, roq_data_itr->sn);
+ __skb_unlink(skb_itr, &roq->queue);
+ i2400m_net_erx(i2400m, skb_itr, roq_data_itr->cs);
+ }
+ roq->ws = 0;
+ d_fnend(2, dev, "(i2400m %p roq %p) = void\n", i2400m, roq);
+ return;
+}
+
+
+/*
+ * Queue a packet
+ *
+ * @i2400m: device descriptor
+ * @cin: Queue Index
+ * @skb: containing the packet data
+ * @fbn: First block number of the packet in @skb
+ * @lbn: Last block number of the packet in @skb
+ *
+ * The hardware is asking the driver to queue a packet for later
+ * delivery to the networking stack.
+ */
+static
+void i2400m_roq_queue(struct i2400m *i2400m, struct i2400m_roq *roq,
+ struct sk_buff * skb, unsigned lbn)
+{
+ struct device *dev = i2400m_dev(i2400m);
+ unsigned nsn, len;
+
+ d_fnstart(2, dev, "(i2400m %p roq %p skb %p lbn %u) = void\n",
+ i2400m, roq, skb, lbn);
+ len = skb_queue_len(&roq->queue);
+ nsn = __i2400m_roq_nsn(roq, lbn);
+ if (unlikely(nsn >= 1024)) {
+ dev_err(dev, "SW BUG? queue nsn %d (lbn %u ws %u)\n",
+ nsn, lbn, roq->ws);
+ i2400m_roq_log_dump(i2400m, roq);
+ i2400m->bus_reset(i2400m, I2400M_RT_WARM);
+ } else {
+ __i2400m_roq_queue(i2400m, roq, skb, lbn, nsn);
+ i2400m_roq_log_add(i2400m, roq, I2400M_RO_TYPE_PACKET,
+ roq->ws, len, lbn, nsn, ~0);
+ }
+ d_fnend(2, dev, "(i2400m %p roq %p skb %p lbn %u) = void\n",
+ i2400m, roq, skb, lbn);
+ return;
+}
+
+
+/*
+ * Update the window start in a reorder queue and deliver all skbs
+ * with a lower window start
+ *
+ * @i2400m: device descriptor
+ * @roq: Reorder queue
+ * @sn: New sequence number
+ */
+static
+void i2400m_roq_update_ws(struct i2400m *i2400m, struct i2400m_roq *roq,
+ unsigned sn)
+{
+ struct device *dev = i2400m_dev(i2400m);
+ unsigned old_ws, nsn, len;
+
+ d_fnstart(2, dev, "(i2400m %p roq %p sn %u)\n", i2400m, roq, sn);
+ old_ws = roq->ws;
+ len = skb_queue_len(&roq->queue);
+ nsn = __i2400m_roq_update_ws(i2400m, roq, sn);
+ i2400m_roq_log_add(i2400m, roq, I2400M_RO_TYPE_WS,
+ old_ws, len, sn, nsn, roq->ws);
+ d_fnstart(2, dev, "(i2400m %p roq %p sn %u) = void\n", i2400m, roq, sn);
+ return;
+}
+
+
+/*
+ * Queue a packet and update the window start
+ *
+ * @i2400m: device descriptor
+ * @cin: Queue Index
+ * @skb: containing the packet data
+ * @fbn: First block number of the packet in @skb
+ * @sn: Last block number of the packet in @skb
+ *
+ * Note that unlike i2400m_roq_update_ws(), which sets the new window
+ * start to @sn, in here we'll set it to @sn + 1.
+ */
+static
+void i2400m_roq_queue_update_ws(struct i2400m *i2400m, struct i2400m_roq *roq,
+ struct sk_buff * skb, unsigned sn)
+{
+ struct device *dev = i2400m_dev(i2400m);
+ unsigned nsn, old_ws, len;
+
+ d_fnstart(2, dev, "(i2400m %p roq %p skb %p sn %u)\n",
+ i2400m, roq, skb, sn);
+ len = skb_queue_len(&roq->queue);
+ nsn = __i2400m_roq_nsn(roq, sn);
+ old_ws = roq->ws;
+ if (unlikely(nsn >= 1024)) {
+ dev_err(dev, "SW BUG? queue_update_ws nsn %u (sn %u ws %u)\n",
+ nsn, sn, roq->ws);
+ i2400m_roq_log_dump(i2400m, roq);
+ i2400m->bus_reset(i2400m, I2400M_RT_WARM);
+ } else {
+ /* if the queue is empty, don't bother as we'd queue
+ * it and inmediately unqueue it -- just deliver it */
+ if (len == 0) {
+ struct i2400m_roq_data *roq_data;
+ roq_data = (struct i2400m_roq_data *) &skb->cb;
+ i2400m_net_erx(i2400m, skb, roq_data->cs);
+ }
+ else {
+ __i2400m_roq_queue(i2400m, roq, skb, sn, nsn);
+ __i2400m_roq_update_ws(i2400m, roq, sn + 1);
+ }
+ i2400m_roq_log_add(i2400m, roq, I2400M_RO_TYPE_PACKET_WS,
+ old_ws, len, sn, nsn, roq->ws);
+ }
+ d_fnend(2, dev, "(i2400m %p roq %p skb %p sn %u) = void\n",
+ i2400m, roq, skb, sn);
+ return;
+}
+
+