4 files changed, 695 insertions, 26 deletions

diff --git a/drivers/net/wimax/i2400m/control.c b/drivers/net/wimax/i2400m/control.c
index 4073c3e93bd4..b3cadb626fe0 100644
--- a/drivers/net/wimax/i2400m/control.c
+++ b/drivers/net/wimax/i2400m/control.c
@@ -1312,10 +1312,12 @@ int i2400m_dev_initialize(struct i2400m *i2400m)
         struct i2400m_tlv_config_idle_parameters idle_params;
         struct i2400m_tlv_config_idle_timeout idle_timeout;
         struct i2400m_tlv_config_d2h_data_format df;
+        struct i2400m_tlv_config_dl_host_reorder dlhr;
         const struct i2400m_tlv_hdr *args[9];
         unsigned argc = 0;
 
         d_fnstart(3, dev, "(i2400m %p)\n", i2400m);
+        /* Disable idle mode? (enabled by default) */
         if (i2400m_idle_mode_disabled) {
                 if (i2400m_le_v1_3(i2400m)) {
                         idle_params.hdr.type =
@@ -1335,12 +1337,24 @@ int i2400m_dev_initialize(struct i2400m *i2400m)
                 }
         }
         if (i2400m_ge_v1_4(i2400m)) {
+                /* Enable extended RX data format? */
                 df.hdr.type =
                         cpu_to_le16(I2400M_TLV_CONFIG_D2H_DATA_FORMAT);
                 df.hdr.length = cpu_to_le16(
                         sizeof(df) - sizeof(df.hdr));
                 df.format = 1;
                 args[argc++] = &df.hdr;
+
+                /* Enable RX data reordering?
+                 * (switch flipped in rx.c:i2400m_rx_setup() after fw upload) */
+                if (i2400m->rx_reorder) {
+                        dlhr.hdr.type =
+                                cpu_to_le16(I2400M_TLV_CONFIG_DL_HOST_REORDER);
+                        dlhr.hdr.length = cpu_to_le16(
+                                sizeof(dlhr) - sizeof(dlhr.hdr));
+                        dlhr.reorder = 1;
+                        args[argc++] = &dlhr.hdr;
+                }
         }
         result = i2400m_set_init_config(i2400m, args, argc);
         if (result < 0)
diff --git a/drivers/net/wimax/i2400m/driver.c b/drivers/net/wimax/i2400m/driver.c
index e4f1ce5bc294..07a54bad237b 100644
--- a/drivers/net/wimax/i2400m/driver.c
+++ b/drivers/net/wimax/i2400m/driver.c
@@ -76,6 +76,11 @@ MODULE_PARM_DESC(idle_mode_disabled,
                  "If true, the device will not enable idle mode negotiation "
                  "with the base station (when connected) to save power.");
 
+int i2400m_rx_reorder_disabled; /* 0 (rx reorder enabled) by default */
+module_param_named(rx_reorder_disabled, i2400m_rx_reorder_disabled, int, 0644);
+MODULE_PARM_DESC(rx_reorder_disabled,
+                 "If true, RX reordering will be disabled.");
+
 /**
  * i2400m_queue_work - schedule work on a i2400m's queue
  *
@@ -396,6 +401,9 @@ retry:
         result = i2400m_tx_setup(i2400m);
         if (result < 0)
                 goto error_tx_setup;
+        result = i2400m_rx_setup(i2400m);
+        if (result < 0)
+                goto error_rx_setup;
         result = i2400m->bus_dev_start(i2400m);
         if (result < 0)
                 goto error_bus_dev_start;
@@ -430,6 +438,8 @@ error_fw_check:
 error_create_workqueue:
         i2400m->bus_dev_stop(i2400m);
 error_bus_dev_start:
+        i2400m_rx_release(i2400m);
+error_rx_setup:
         i2400m_tx_release(i2400m);
 error_tx_setup:
 error_bootstrap:
@@ -477,6 +487,7 @@ void __i2400m_dev_stop(struct i2400m *i2400m)
         i2400m->ready = 0;
         destroy_workqueue(i2400m->work_queue);
         i2400m->bus_dev_stop(i2400m);
+        i2400m_rx_release(i2400m);
         i2400m_tx_release(i2400m);
         wimax_state_change(wimax_dev, WIMAX_ST_DOWN);
         d_fnend(3, dev, "(i2400m %p) = 0\n", i2400m);
diff --git a/drivers/net/wimax/i2400m/i2400m.h b/drivers/net/wimax/i2400m/i2400m.h
index 125c30594e63..3ae2df38b59a 100644
--- a/drivers/net/wimax/i2400m/i2400m.h
+++ b/drivers/net/wimax/i2400m/i2400m.h
@@ -174,6 +174,7 @@ enum i2400m_reset_type {
 };
 
 struct i2400m_reset_ctx;
+struct i2400m_roq;
 
 /**
  * struct i2400m - descriptor for an Intel 2400m
@@ -257,6 +258,9 @@ struct i2400m_reset_ctx;
  *     force this to be the first field so that we can get from
  *     netdev_priv() the right pointer.
  *
+ * @rx_reorder: 1 if RX reordering is enabled; this can only be
+ *     set at probe time.
+ *
  * @state: device's state (as reported by it)
  *
  * @state_wq: waitqueue that is woken up whenever the state changes
@@ -313,6 +317,12 @@ struct i2400m_reset_ctx;
  *
  * @rx_size_max: buggest RX message received.
  *
+ * @rx_roq: RX ReOrder queues. (fw >= v1.4) When packets are received
+ *     out of order, the device will ask the driver to hold certain
+ *     packets until the ones that are received out of order can be
+ *     delivered. Then the driver can release them to the host. See
+ *     drivers/net/i2400m/rx.c for details.
+ *
  * @init_mutex: Mutex used for serializing the device bringup
  *     sequence; this way if the device reboots in the middle, we
  *     don't try to do a bringup again while we are tearing down the
@@ -377,6 +387,7 @@ struct i2400m {
         unsigned boot_mode:1;           /* is the device in boot mode? */
         unsigned sboot:1;               /* signed or unsigned fw boot */
         unsigned ready:1;               /* all probing steps done */
+        unsigned rx_reorder:1;          /* RX reorder is enabled */
         u8 trace_msg_from_user;         /* echo rx msgs to 'trace' pipe */
                                         /* typed u8 so debugfs/u8 can tweak */
         enum i2400m_system_state state;
@@ -405,10 +416,11 @@ struct i2400m {
         unsigned tx_pl_num, tx_pl_max, tx_pl_min,
                 tx_num, tx_size_acc, tx_size_min, tx_size_max;
 
-        /* RX stats */
+        /* RX stuff */
         spinlock_t rx_lock;             /* protect RX state */
         unsigned rx_pl_num, rx_pl_max, rx_pl_min,
                 rx_num, rx_size_acc, rx_size_min, rx_size_max;
+        struct i2400m_roq *rx_roq;      /* not under rx_lock! */
 
         struct mutex msg_mutex;         /* serialize command execution */
         struct completion msg_completion;
@@ -442,6 +454,7 @@ void i2400m_init(struct i2400m *i2400m)
         wimax_dev_init(&i2400m->wimax_dev);
 
         i2400m->boot_mode = 1;
+        i2400m->rx_reorder = 1;
         init_waitqueue_head(&i2400m->state_wq);
 
         spin_lock_init(&i2400m->tx_lock);
@@ -591,6 +604,9 @@ extern int i2400m_tx_setup(struct i2400m *);
 extern void i2400m_wake_tx_work(struct work_struct *);
 extern void i2400m_tx_release(struct i2400m *);
 
+extern int i2400m_rx_setup(struct i2400m *);
+extern void i2400m_rx_release(struct i2400m *);
+
 extern void i2400m_net_rx(struct i2400m *, struct sk_buff *, unsigned,
                           const void *, int);
 extern void i2400m_net_erx(struct i2400m *, struct sk_buff *,
@@ -788,6 +804,7 @@ void __i2400m_msleep(unsigned ms)
 /* Module parameters */
 
 extern int i2400m_idle_mode_disabled;
+extern int i2400m_rx_reorder_disabled;
 
 
 #endif /* #ifndef __I2400M_H__ */
diff --git a/drivers/net/wimax/i2400m/rx.c b/drivers/net/wimax/i2400m/rx.c
index cd525066d4b7..02419bfd64b5 100644
--- a/drivers/net/wimax/i2400m/rx.c
+++ b/drivers/net/wimax/i2400m/rx.c
@@ -39,7 +39,7 @@
  *  - Use skb_clone(), break up processing in chunks
  *  - Split transport/device specific
  *  - Make buffer size dynamic to exert less memory pressure
- *
+ *  - RX reorder support
  *
  * This handles the RX path.
  *
@@ -77,14 +77,42 @@
  * In firmware >= 1.4, RX packets have an extended header (16
  * bytes). This header conveys information for management of host
  * reordering of packets (the device offloads storage of the packets
- * for reordering to the host).
- *
- * Currently this information is not used as the current code doesn't
- * enable host reordering.
+ * for reordering to the host). Read below for more information.
  *
  * The header is used as dummy space to emulate an ethernet header and
  * thus be able to act as an ethernet device without having to reallocate.
  *
+ * DATA RX REORDERING
+ *
+ * Starting in firmware v1.4, the device can deliver packets for
+ * delivery with special reordering information; this allows it to
+ * more effectively do packet management when some frames were lost in
+ * the radio traffic.
+ *
+ * Thus, for RX packets that come out of order, the device gives the
+ * driver enough information to queue them properly and then at some
+ * point, the signal to deliver the whole (or part) of the queued
+ * packets to the networking stack. There are 16 such queues.
+ *
+ * This only happens when a packet comes in with the "need reorder"
+ * flag set in the RX header. When such bit is set, the following
+ * operations might be indicated:
+ *
+ *  - reset queue: send all queued packets to the OS
+ *
+ *  - queue: queue a packet
+ *
+ *  - update ws: update the queue's window start and deliver queued
+ *    packets that meet the criteria
+ *
+ *  - queue & update ws: queue a packet, update the window start and
+ *    deliver queued packets that meet the criteria
+ *
+ * (delivery criteria: the packet's [normalized] sequence number is
+ * lower than the new [normalized] window start).
+ *
+ * See the i2400m_roq_*() functions for details.
+ *
  * ROADMAP
  *
  * i2400m_rx
@@ -94,6 +122,17 @@
  *     i2400m_net_rx
  *     i2400m_rx_edata
  *       i2400m_net_erx
+ *       i2400m_roq_reset
+ *         i2400m_net_erx
+ *       i2400m_roq_queue
+ *         __i2400m_roq_queue
+ *       i2400m_roq_update_ws
+ *         __i2400m_roq_update_ws
+ *           i2400m_net_erx
+ *       i2400m_roq_queue_update_ws
+ *         __i2400m_roq_queue
+ *         __i2400m_roq_update_ws
+ *           i2400m_net_erx
  *     i2400m_rx_ctl
  *       i2400m_msg_size_check
  *       i2400m_report_hook_work    [in a workqueue]
@@ -330,6 +369,469 @@ error_check:
         return;
 }
 
+
+/*
+ * 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;
+}
+
+
 /*
  * Receive and send up an extended data packet
  *
@@ -347,6 +849,28 @@ error_check:
  * having to copy packets around.
  *
  * This function handles said path.
+ *
+ *
+ * Receive and send up an extended data packet that requires no reordering
+ *
+ * @i2400m: device descriptor
+ * @skb_rx: skb that contains the extended data packet
+ * @single_last: 1 if the payload is the only one or the last one of
+ *     the skb.
+ * @payload: pointer to the packet's data (past the actual extended
+ *     data payload header).
+ * @size: size of the payload
+ *
+ * Pass over to the networking stack a data packet that might have
+ * reordering requirements.
+ *
+ * This needs to the decide if the skb in which the packet is
+ * contained can be reused or if it needs to be cloned. Then it has to
+ * be trimmed in the edges so that the beginning is the space for eth
+ * header and then pass it to i2400m_net_erx() for the stack
+ *
+ * Assumes the caller has verified the sanity of the payload (size,
+ * etc) already.
  */
 static
 void i2400m_rx_edata(struct i2400m *i2400m, struct sk_buff *skb_rx,
@@ -357,53 +881,86 @@ void i2400m_rx_edata(struct i2400m *i2400m, struct sk_buff *skb_rx,
         struct net_device *net_dev = i2400m->wimax_dev.net_dev;
         struct sk_buff *skb;
         enum i2400m_cs cs;
-        unsigned reorder_needed;
+        u32 reorder;
+        unsigned ro_needed, ro_type, ro_cin, ro_sn;
+        struct i2400m_roq *roq;
+        struct i2400m_roq_data *roq_data;
 
-        d_fnstart(4, dev, "(i2400m %p skb_rx %p single %u payload %p "
+        BUILD_BUG_ON(ETH_HLEN > sizeof(*hdr));
+
+        d_fnstart(2, dev, "(i2400m %p skb_rx %p single %u payload %p "
                   "size %zu)\n", i2400m, skb_rx, single_last, payload, size);
         if (size < sizeof(*hdr)) {
                 dev_err(dev, "ERX: HW BUG? message with short header (%zu "
                         "vs %zu bytes expected)\n", size, sizeof(*hdr));
                 goto error;
         }
-        reorder_needed = le32_to_cpu(hdr->reorder & I2400M_REORDER_NEEDED);
-        cs = hdr->cs;
-        if (reorder_needed) {
-                dev_err(dev, "ERX: HW BUG? reorder needed, it was disabled\n");
-                goto error;
-        }
-        /* ok, so now decide if we want to clone or reuse the skb,
-         * pull and trim it so the beginning is the space for the eth
-         * header and pass it to i2400m_net_erx() for the stack */
+
         if (single_last) {
                 skb = skb_get(skb_rx);
-                d_printf(3, dev, "ERX: reusing single payload skb %p\n", skb);
+                d_printf(3, dev, "ERX: skb %p reusing\n", skb);
         } else {
                 skb = skb_clone(skb_rx, GFP_KERNEL);
-                d_printf(3, dev, "ERX: cloning %p\n", skb);
                 if (skb == NULL) {
                         dev_err(dev, "ERX: no memory to clone skb\n");
                         net_dev->stats.rx_dropped++;
                         goto error_skb_clone;
                 }
+                d_printf(3, dev, "ERX: skb %p cloned from %p\n", skb, skb_rx);
         }
         /* now we have to pull and trim so that the skb points to the
          * beginning of the IP packet; the netdev part will add the
-         * ethernet header as needed. */
-        BUILD_BUG_ON(ETH_HLEN > sizeof(*hdr));
+         * ethernet header as needed - we know there is enough space
+         * because we checked in i2400m_rx_edata(). */
         skb_pull(skb, payload + sizeof(*hdr) - (void *) skb->data);
-        skb_trim(skb, (void *) skb_end_pointer(skb) - payload + sizeof(*hdr));
-        i2400m_net_erx(i2400m, skb, cs);
+        skb_trim(skb, (void *) skb_end_pointer(skb) - payload - sizeof(*hdr));
+
+        reorder = le32_to_cpu(hdr->reorder);
+        ro_needed = reorder & I2400M_RO_NEEDED;
+        cs = hdr->cs;
+        if (ro_needed) {
+                ro_type = (reorder >> I2400M_RO_TYPE_SHIFT) & I2400M_RO_TYPE;
+                ro_cin = (reorder >> I2400M_RO_CIN_SHIFT) & I2400M_RO_CIN;
+                ro_sn = (reorder >> I2400M_RO_SN_SHIFT) & I2400M_RO_SN;
+
+                roq = &i2400m->rx_roq[ro_cin];
+                roq_data = (struct i2400m_roq_data *) &skb->cb;
+                roq_data->sn = ro_sn;
+                roq_data->cs = cs;
+                d_printf(2, dev, "ERX: reorder needed: "
+                         "type %u cin %u [ws %u] sn %u/%u len %zuB\n",
+                         ro_type, ro_cin, roq->ws, ro_sn,
+                         __i2400m_roq_nsn(roq, ro_sn), size);
+                d_dump(2, dev, payload, size);
+                switch(ro_type) {
+                case I2400M_RO_TYPE_RESET:
+                        i2400m_roq_reset(i2400m, roq);
+                        kfree_skb(skb); /* no data here */
+                        break;
+                case I2400M_RO_TYPE_PACKET:
+                        i2400m_roq_queue(i2400m, roq, skb, ro_sn);
+                        break;
+                case I2400M_RO_TYPE_WS:
+                        i2400m_roq_update_ws(i2400m, roq, ro_sn);
+                        kfree_skb(skb); /* no data here */
+                        break;
+                case I2400M_RO_TYPE_PACKET_WS:
+                        i2400m_roq_queue_update_ws(i2400m, roq, skb, ro_sn);
+                        break;
+                default:
+                        dev_err(dev, "HW BUG? unknown reorder type %u\n", ro_type);
+                }
+        }
+        else
+                i2400m_net_erx(i2400m, skb, cs);
 error_skb_clone:
 error:
-        d_fnend(4, dev, "(i2400m %p skb_rx %p single %u payload %p "
+        d_fnend(2, dev, "(i2400m %p skb_rx %p single %u payload %p "
                 "size %zu) = void\n", i2400m, skb_rx, single_last, payload, size);
         return;
 }
 
 
-
-
 /*
  * Act on a received payload
  *
@@ -632,3 +1189,73 @@ error_msg_hdr_check:
         return result;
 }
 EXPORT_SYMBOL_GPL(i2400m_rx);
+
+
+/*
+ * Initialize the RX queue and infrastructure
+ *
+ * This sets up all the RX reordering infrastructures, which will not
+ * be used if reordering is not enabled or if the firmware does not
+ * support it. The device is told to do reordering in
+ * i2400m_dev_initialize(), where it also looks at the value of the
+ * i2400m->rx_reorder switch before taking a decission.
+ *
+ * Note we allocate the roq queues in one chunk and the actual logging
+ * support for it (logging) in another one and then we setup the
+ * pointers from the first to the last.
+ */
+int i2400m_rx_setup(struct i2400m *i2400m)
+{
+        int result = 0;
+        struct device *dev = i2400m_dev(i2400m);
+
+        i2400m->rx_reorder = i2400m_rx_reorder_disabled? 0 : 1;
+        if (i2400m->rx_reorder) {
+                unsigned itr;
+                size_t size;
+                struct i2400m_roq_log *rd;
+
+                result = -ENOMEM;
+
+                size = sizeof(i2400m->rx_roq[0]) * (I2400M_RO_CIN + 1);
+                i2400m->rx_roq = kzalloc(size, GFP_KERNEL);
+                if (i2400m->rx_roq == NULL) {
+                        dev_err(dev, "RX: cannot allocate %zu bytes for "
+                                "reorder queues\n", size);
+                        goto error_roq_alloc;
+                }
+
+                size = sizeof(*i2400m->rx_roq[0].log) * (I2400M_RO_CIN + 1);
+                rd = kzalloc(size, GFP_KERNEL);
+                if (rd == NULL) {
+                        dev_err(dev, "RX: cannot allocate %zu bytes for "
+                                "reorder queues log areas\n", size);
+                        result = -ENOMEM;
+                        goto error_roq_log_alloc;
+                }
+
+                for(itr = 0; itr < I2400M_RO_CIN + 1; itr++) {
+                        __i2400m_roq_init(&i2400m->rx_roq[itr]);
+                        i2400m->rx_roq[itr].log = &rd[itr];
+                }
+        }
+        return 0;
+
+error_roq_log_alloc:
+        kfree(i2400m->rx_roq);
+error_roq_alloc:
+        return result;
+}
+
+
+/* Tear down the RX queue and infrastructure */
+void i2400m_rx_release(struct i2400m *i2400m)
+{
+        if (i2400m->rx_reorder) {
+                unsigned itr;
+                for(itr = 0; itr < I2400M_RO_CIN + 1; itr++)
+                        __skb_queue_purge(&i2400m->rx_roq[itr].queue);
+                kfree(i2400m->rx_roq[0].log);
+                kfree(i2400m->rx_roq);
+        }
+}