rx.c

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/*
 * Intel Wireless WiMAX Connection 2400m
 * Handle incoming traffic and deliver it to the control or data planes
 *
 *
 * Copyright (C) 2007-2008 Intel Corporation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *   * Neither the name of Intel Corporation nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *
 * Intel Corporation <[email protected]>
 * Yanir Lubetkin <[email protected]>
 *  - Initial implementation
 * Inaky Perez-Gonzalez <[email protected]>
 *  - 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.
 *
 * We receive an RX message from the bus-specific driver, which
 * contains one or more payloads that have potentially different
 * destinataries (data or control paths).
 *
 * So we just take that payload from the transport specific code in
 * the form of an skb, break it up in chunks (a cloned skb each in the
 * case of network packets) and pass it to netdev or to the
 * command/ack handler (and from there to the WiMAX stack).
 *
 * PROTOCOL FORMAT
 *
 * The format of the buffer is:
 *
 * HEADER                      (struct i2400m_msg_hdr)
 * PAYLOAD DESCRIPTOR 0        (struct i2400m_pld)
 * PAYLOAD DESCRIPTOR 1
 * ...
 * PAYLOAD DESCRIPTOR N
 * PAYLOAD 0                   (raw bytes)
 * PAYLOAD 1
 * ...
 * PAYLOAD N
 *
 * See tx.c for a deeper description on alignment requirements and
 * other fun facts of it.
 *
 * DATA PACKETS
 *
 * In firmwares <= v1.3, data packets have no header for RX, but they
 * do for TX (currently unused).
 *
 * 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). 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
 *   i2400m_rx_msg_hdr_check
 *   i2400m_rx_pl_descr_check
 *   i2400m_rx_payload
 *     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]
 *         i2400m_report_hook
 *       wimax_msg_to_user
 *       i2400m_rx_ctl_ack
 *         wimax_msg_to_user_alloc
 *     i2400m_rx_trace
 *       i2400m_msg_size_check
 *       wimax_msg
 */
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/if_arp.h>
#include <linux/netdevice.h>
#include <linux/workqueue.h>
#include <linux/export.h>
#include <linux/moduleparam.h>
#include "i2400m.h"


#define D_SUBMODULE rx
#include "debug-levels.h"

static 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.");

struct i2400m_report_hook_args {
    struct sk_buff *skb_rx;
    const struct i2400m_l3l4_hdr *l3l4_hdr;
    size_t size;
    struct list_head list_node;
};


/*
 * Execute i2400m_report_hook in a workqueue
 *
 * Goes over the list of queued reports in i2400m->rx_reports and
 * processes them.
 *
 * NOTE: refcounts on i2400m are not needed because we flush the
 *     workqueue this runs on (i2400m->work_queue) before destroying
 *     i2400m.
 */
void i2400m_report_hook_work(struct work_struct *ws)
{
    struct i2400m *i2400m = container_of(ws, struct i2400m, rx_report_ws);
    struct device *dev = i2400m_dev(i2400m);
    struct i2400m_report_hook_args *args, *args_next;
    LIST_HEAD(list);
    unsigned long flags;

    while (1) {
        spin_lock_irqsave(&i2400m->rx_lock, flags);
        list_splice_init(&i2400m->rx_reports, &list);
        spin_unlock_irqrestore(&i2400m->rx_lock, flags);
        if (list_empty(&list))
            break;
        else
            d_printf(1, dev, "processing queued reports\n");
        list_for_each_entry_safe(args, args_next, &list, list_node) {
            d_printf(2, dev, "processing queued report %p\n", args);
            i2400m_report_hook(i2400m, args->l3l4_hdr, args->size);
            kfree_skb(args->skb_rx);
            list_del(&args->list_node);
            kfree(args);
        }
    }
}


/*
 * Flush the list of queued reports
 */
static
void i2400m_report_hook_flush(struct i2400m *i2400m)
{
    struct device *dev = i2400m_dev(i2400m);
    struct i2400m_report_hook_args *args, *args_next;
    LIST_HEAD(list);
    unsigned long flags;

    d_printf(1, dev, "flushing queued reports\n");
    spin_lock_irqsave(&i2400m->rx_lock, flags);
    list_splice_init(&i2400m->rx_reports, &list);
    spin_unlock_irqrestore(&i2400m->rx_lock, flags);
    list_for_each_entry_safe(args, args_next, &list, list_node) {
        d_printf(2, dev, "flushing queued report %p\n", args);
        kfree_skb(args->skb_rx);
        list_del(&args->list_node);
        kfree(args);
    }
}


/*
 * Queue a report for later processing
 *
 * @i2400m: device descriptor
 * @skb_rx: skb that contains the payload (for reference counting)
 * @l3l4_hdr: pointer to the control
 * @size: size of the message
 */
static
void i2400m_report_hook_queue(struct i2400m *i2400m, struct sk_buff *skb_rx,
                  const void *l3l4_hdr, size_t size)
{
    struct device *dev = i2400m_dev(i2400m);
    unsigned long flags;
    struct i2400m_report_hook_args *args;

    args = kzalloc(sizeof(*args), GFP_NOIO);
    if (args) {
        args->skb_rx = skb_get(skb_rx);
        args->l3l4_hdr = l3l4_hdr;
        args->size = size;
        spin_lock_irqsave(&i2400m->rx_lock, flags);
        list_add_tail(&args->list_node, &i2400m->rx_reports);
        spin_unlock_irqrestore(&i2400m->rx_lock, flags);
        d_printf(2, dev, "queued report %p\n", args);
        rmb();      /* see i2400m->ready's documentation  */
        if (likely(i2400m->ready))  /* only send if up */
            queue_work(i2400m->work_queue, &i2400m->rx_report_ws);
    } else  {
        if (printk_ratelimit())
            dev_err(dev, "%s:%u: Can't allocate %zu B\n",
                __func__, __LINE__, sizeof(*args));
    }
}


/*
 * Process an ack to a command
 *
 * @i2400m: device descriptor
 * @payload: pointer to message
 * @size: size of the message
 *
 * Pass the acknodledgment (in an skb) to the thread that is waiting
 * for it in i2400m->msg_completion.
 *
 * We need to coordinate properly with the thread waiting for the
 * ack. Check if it is waiting or if it is gone. We loose the spinlock
 * to avoid allocating on atomic contexts (yeah, could use GFP_ATOMIC,
 * but this is not so speed critical).
 */
static
void i2400m_rx_ctl_ack(struct i2400m *i2400m,
               const void *payload, size_t size)
{
    struct device *dev = i2400m_dev(i2400m);
    struct wimax_dev *wimax_dev = &i2400m->wimax_dev;
    unsigned long flags;
    struct sk_buff *ack_skb;

    /* Anyone waiting for an answer? */
    spin_lock_irqsave(&i2400m->rx_lock, flags);
    if (i2400m->ack_skb != ERR_PTR(-EINPROGRESS)) {
        dev_err(dev, "Huh? reply to command with no waiters\n");
        goto error_no_waiter;
    }
    spin_unlock_irqrestore(&i2400m->rx_lock, flags);

    ack_skb = wimax_msg_alloc(wimax_dev, NULL, payload, size, GFP_KERNEL);

    /* Check waiter didn't time out waiting for the answer... */
    spin_lock_irqsave(&i2400m->rx_lock, flags);
    if (i2400m->ack_skb != ERR_PTR(-EINPROGRESS)) {
        d_printf(1, dev, "Huh? waiter for command reply cancelled\n");
        goto error_waiter_cancelled;
    }
    if (IS_ERR(ack_skb))
        dev_err(dev, "CMD/GET/SET ack: cannot allocate SKB\n");
    i2400m->ack_skb = ack_skb;
    spin_unlock_irqrestore(&i2400m->rx_lock, flags);
    complete(&i2400m->msg_completion);
    return;

error_waiter_cancelled:
    if (!IS_ERR(ack_skb))
        kfree_skb(ack_skb);
error_no_waiter:
    spin_unlock_irqrestore(&i2400m->rx_lock, flags);
}


/*
 * Receive and process a control payload
 *
 * @i2400m: device descriptor
 * @skb_rx: skb that contains the payload (for reference counting)
 * @payload: pointer to message
 * @size: size of the message
 *
 * There are two types of control RX messages: reports (asynchronous,
 * like your every day interrupts) and 'acks' (reponses to a command,
 * get or set request).
 *
 * If it is a report, we run hooks on it (to extract information for
 * things we need to do in the driver) and then pass it over to the
 * WiMAX stack to send it to user space.
 *
 * NOTE: report processing is done in a workqueue specific to the
 *     generic driver, to avoid deadlocks in the system.
 *
 * If it is not a report, it is an ack to a previously executed
 * command, set or get, so wake up whoever is waiting for it from
 * i2400m_msg_to_dev(). i2400m_rx_ctl_ack() takes care of that.
 *
 * Note that the sizes we pass to other functions from here are the
 * sizes of the _l3l4_hdr + payload, not full buffer sizes, as we have
 * verified in _msg_size_check() that they are congruent.
 *
 * For reports: We can't clone the original skb where the data is
 * because we need to send this up via netlink; netlink has to add
 * headers and we can't overwrite what's preceding the payload...as
 * it is another message. So we just dup them.
 */
static
void i2400m_rx_ctl(struct i2400m *i2400m, struct sk_buff *skb_rx,
           const void *payload, size_t size)
{
    int result;
    struct device *dev = i2400m_dev(i2400m);
    const struct i2400m_l3l4_hdr *l3l4_hdr = payload;
    unsigned msg_type;

    result = i2400m_msg_size_check(i2400m, l3l4_hdr, size);
    if (result < 0) {
        dev_err(dev, "HW BUG? device sent a bad message: %d\n",
            result);
        goto error_check;
    }
    msg_type = le16_to_cpu(l3l4_hdr->type);
    d_printf(1, dev, "%s 0x%04x: %zu bytes\n",
         msg_type & I2400M_MT_REPORT_MASK ? "REPORT" : "CMD/SET/GET",
         msg_type, size);
    d_dump(2, dev, l3l4_hdr, size);
    if (msg_type & I2400M_MT_REPORT_MASK) {
        /*
         * Process each report
         *
         * - has to be ran serialized as well
         *
         * - the handling might force the execution of
         *   commands. That might cause reentrancy issues with
         *   bus-specific subdrivers and workqueues, so the we
         *   run it in a separate workqueue.
         *
         * - when the driver is not yet ready to handle them,
         *   they are queued and at some point the queue is
         *   restarted [NOTE: we can't queue SKBs directly, as
         *   this might be a piece of a SKB, not the whole
         *   thing, and this is cheaper than cloning the
         *   SKB].
         *
         * Note we don't do refcounting for the device
         * structure; this is because before destroying
         * 'i2400m', we make sure to flush the
         * i2400m->work_queue, so there are no issues.
         */
        i2400m_report_hook_queue(i2400m, skb_rx, l3l4_hdr, size);
        if (unlikely(i2400m->trace_msg_from_user))
            wimax_msg(&i2400m->wimax_dev, "echo",
                  l3l4_hdr, size, GFP_KERNEL);
        result = wimax_msg(&i2400m->wimax_dev, NULL, l3l4_hdr, size,
                   GFP_KERNEL);
        if (result < 0)
            dev_err(dev, "error sending report to userspace: %d\n",
                result);
    } else      /* an ack to a CMD, GET or SET */
        i2400m_rx_ctl_ack(i2400m, payload, size);
error_check:
    return;
}


/*
 * Receive and send up a trace
 *
 * @i2400m: device descriptor
 * @skb_rx: skb that contains the trace (for reference counting)
 * @payload: pointer to trace message inside the skb
 * @size: size of the message
 *
 * THe i2400m might produce trace information (diagnostics) and we
 * send them through a different kernel-to-user pipe (to avoid
 * clogging it).
 *
 * As in i2400m_rx_ctl(), we can't clone the original skb where the
 * data is because we need to send this up via netlink; netlink has to
 * add headers and we can't overwrite what's preceding the
 * payload...as it is another message. So we just dup them.
 */
static
void i2400m_rx_trace(struct i2400m *i2400m,
             const void *payload, size_t size)
{
    int result;
    struct device *dev = i2400m_dev(i2400m);
    struct wimax_dev *wimax_dev = &i2400m->wimax_dev;
    const struct i2400m_l3l4_hdr *l3l4_hdr = payload;
    unsigned msg_type;

    result = i2400m_msg_size_check(i2400m, l3l4_hdr, size);
    if (result < 0) {
        dev_err(dev, "HW BUG? device sent a bad trace message: %d\n",
            result);
        goto error_check;
    }
    msg_type = le16_to_cpu(l3l4_hdr->type);
    d_printf(1, dev, "Trace %s 0x%04x: %zu bytes\n",
         msg_type & I2400M_MT_REPORT_MASK ? "REPORT" : "CMD/SET/GET",
         msg_type, size);
    d_dump(2, dev, l3l4_hdr, size);
    result = wimax_msg(wimax_dev, "trace", l3l4_hdr, size, GFP_KERNEL);
    if (result < 0)
        dev_err(dev, "error sending trace to userspace: %d\n",
            result);
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);
}


/*
 * 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);
    /*
     * For type 2(update_window_start) rx messages, there is no
     * need to check if the normalized sequence number is greater 1023.
     * Simply insert and deliver all packets to the host up to the
     * window start.
     */
    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);
}


/*
 * 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_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);
}


/*
 * 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);
}


/*
 * 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);
    /*
     * For type 3(queue_update_window_start) rx messages, there is no
     * need to check if the normalized sequence number is greater 1023.
     * Simply insert and deliver all packets to the host up to the
     * window start.
     */
    old_ws = roq->ws;
    /* If the queue is empty, don't bother as we'd queue
     * it and immediately 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);
}


/*
 * This routine destroys the memory allocated for rx_roq, when no
 * other thread is accessing it. Access to rx_roq is refcounted by
 * rx_roq_refcount, hence memory allocated must be destroyed when
 * rx_roq_refcount becomes zero. This routine gets executed when
 * rx_roq_refcount becomes zero.
 */
static void i2400m_rx_roq_destroy(struct kref *ref)
{
    unsigned itr;
    struct i2400m *i2400m
            = container_of(ref, struct i2400m, rx_roq_refcount);
    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);
    i2400m->rx_roq = NULL;
}

/*
 * Receive and send up an extended data packet
 *
 * @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 inside the skb
 * @size: size of the payload
 *
 * Starting in v1.4 of the i2400m's firmware, the device can send data
 * packets to the host in an extended format that; this incudes a 16
 * byte header (struct i2400m_pl_edata_hdr). Using this header's space
 * we can fake ethernet headers for ethernet device emulation without
 * 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,
             unsigned single_last, const void *payload, size_t size)
{
    struct device *dev = i2400m_dev(i2400m);
    const struct i2400m_pl_edata_hdr *hdr = payload;
    struct net_device *net_dev = i2400m->wimax_dev.net_dev;
    struct sk_buff *skb;
    enum i2400m_cs cs;
    u32 reorder;
    unsigned ro_needed, ro_type, ro_cin, ro_sn;
    struct i2400m_roq *roq;
    struct i2400m_roq_data *roq_data;
    unsigned long flags;

    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;
    }

    if (single_last) {
        skb = skb_get(skb_rx);
        d_printf(3, dev, "ERX: skb %p reusing\n", skb);
    } else {
        skb = skb_clone(skb_rx, GFP_KERNEL);
        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 - 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));

    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;

        spin_lock_irqsave(&i2400m->rx_lock, flags);
        if (i2400m->rx_roq == NULL) {
            kfree_skb(skb); /* rx_roq is already destroyed */
            spin_unlock_irqrestore(&i2400m->rx_lock, flags);
            goto error;
        }
        roq = &i2400m->rx_roq[ro_cin];
        kref_get(&i2400m->rx_roq_refcount);
        spin_unlock_irqrestore(&i2400m->rx_lock, flags);

        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);
        }

        spin_lock_irqsave(&i2400m->rx_lock, flags);
        kref_put(&i2400m->rx_roq_refcount, i2400m_rx_roq_destroy);
        spin_unlock_irqrestore(&i2400m->rx_lock, flags);
    }
    else
        i2400m_net_erx(i2400m, skb, cs);
error_skb_clone:
error:
    d_fnend(2, dev, "(i2400m %p skb_rx %p single %u payload %p "
        "size %zu) = void\n", i2400m, skb_rx, single_last, payload, size);
}


/*
 * Act on a received payload
 *
 * @i2400m: device instance
 * @skb_rx: skb where the transaction was received
 * @single_last: 1 this is the only payload or the last one (so the
 *     skb can be reused instead of cloned).
 * @pld: payload descriptor
 * @payload: payload data
 *
 * Upon reception of a payload, look at its guts in the payload
 * descriptor and decide what to do with it. If it is a single payload
 * skb or if the last skb is a data packet, the skb will be referenced
 * and modified (so it doesn't have to be cloned).
 */
static
void i2400m_rx_payload(struct i2400m *i2400m, struct sk_buff *skb_rx,
               unsigned single_last, const struct i2400m_pld *pld,
               const void *payload)
{
    struct device *dev = i2400m_dev(i2400m);
    size_t pl_size = i2400m_pld_size(pld);
    enum i2400m_pt pl_type = i2400m_pld_type(pld);

    d_printf(7, dev, "RX: received payload type %u, %zu bytes\n",
         pl_type, pl_size);
    d_dump(8, dev, payload, pl_size);

    switch (pl_type) {
    case I2400M_PT_DATA:
        d_printf(3, dev, "RX: data payload %zu bytes\n", pl_size);
        i2400m_net_rx(i2400m, skb_rx, single_last, payload, pl_size);
        break;
    case I2400M_PT_CTRL:
        i2400m_rx_ctl(i2400m, skb_rx, payload, pl_size);
        break;
    case I2400M_PT_TRACE:
        i2400m_rx_trace(i2400m, payload, pl_size);
        break;
    case I2400M_PT_EDATA:
        d_printf(3, dev, "ERX: data payload %zu bytes\n", pl_size);
        i2400m_rx_edata(i2400m, skb_rx, single_last, payload, pl_size);
        break;
    default:    /* Anything else shouldn't come to the host */
        if (printk_ratelimit())
            dev_err(dev, "RX: HW BUG? unexpected payload type %u\n",
                pl_type);
    }
}


/*
 * Check a received transaction's message header
 *
 * @i2400m: device descriptor
 * @msg_hdr: message header
 * @buf_size: size of the received buffer
 *
 * Check that the declarations done by a RX buffer message header are
 * sane and consistent with the amount of data that was received.
 */
static
int i2400m_rx_msg_hdr_check(struct i2400m *i2400m,
                const struct i2400m_msg_hdr *msg_hdr,
                size_t buf_size)
{
    int result = -EIO;
    struct device *dev = i2400m_dev(i2400m);
    if (buf_size < sizeof(*msg_hdr)) {
        dev_err(dev, "RX: HW BUG? message with short header (%zu "
            "vs %zu bytes expected)\n", buf_size, sizeof(*msg_hdr));
        goto error;
    }
    if (msg_hdr->barker != cpu_to_le32(I2400M_D2H_MSG_BARKER)) {
        dev_err(dev, "RX: HW BUG? message received with unknown "
            "barker 0x%08x (buf_size %zu bytes)\n",
            le32_to_cpu(msg_hdr->barker), buf_size);
        goto error;
    }
    if (msg_hdr->num_pls == 0) {
        dev_err(dev, "RX: HW BUG? zero payload packets in message\n");
        goto error;
    }
    if (le16_to_cpu(msg_hdr->num_pls) > I2400M_MAX_PLS_IN_MSG) {
        dev_err(dev, "RX: HW BUG? message contains more payload "
            "than maximum; ignoring.\n");
        goto error;
    }
    result = 0;
error:
    return result;
}


/*
 * Check a payload descriptor against the received data
 *
 * @i2400m: device descriptor
 * @pld: payload descriptor
 * @pl_itr: offset (in bytes) in the received buffer the payload is
 *          located
 * @buf_size: size of the received buffer
 *
 * Given a payload descriptor (part of a RX buffer), check it is sane
 * and that the data it declares fits in the buffer.
 */
static
int i2400m_rx_pl_descr_check(struct i2400m *i2400m,
                  const struct i2400m_pld *pld,
                  size_t pl_itr, size_t buf_size)
{
    int result = -EIO;
    struct device *dev = i2400m_dev(i2400m);
    size_t pl_size = i2400m_pld_size(pld);
    enum i2400m_pt pl_type = i2400m_pld_type(pld);

    if (pl_size > i2400m->bus_pl_size_max) {
        dev_err(dev, "RX: HW BUG? payload @%zu: size %zu is "
            "bigger than maximum %zu; ignoring message\n",
            pl_itr, pl_size, i2400m->bus_pl_size_max);
        goto error;
    }
    if (pl_itr + pl_size > buf_size) {  /* enough? */
        dev_err(dev, "RX: HW BUG? payload @%zu: size %zu "
            "goes beyond the received buffer "
            "size (%zu bytes); ignoring message\n",
            pl_itr, pl_size, buf_size);
        goto error;
    }
    if (pl_type >= I2400M_PT_ILLEGAL) {
        dev_err(dev, "RX: HW BUG? illegal payload type %u; "
            "ignoring message\n", pl_type);
        goto error;
    }
    result = 0;
error:
    return result;
}


int i2400m_rx(struct i2400m *i2400m, struct sk_buff *skb)
{
    int i, result;
    struct device *dev = i2400m_dev(i2400m);
    const struct i2400m_msg_hdr *msg_hdr;
    size_t pl_itr, pl_size;
    unsigned long flags;
    unsigned num_pls, single_last, skb_len;

    skb_len = skb->len;
    d_fnstart(4, dev, "(i2400m %p skb %p [size %u])\n",
          i2400m, skb, skb_len);
    result = -EIO;
    msg_hdr = (void *) skb->data;
    result = i2400m_rx_msg_hdr_check(i2400m, msg_hdr, skb_len);
    if (result < 0)
        goto error_msg_hdr_check;
    result = -EIO;
    num_pls = le16_to_cpu(msg_hdr->num_pls);
    pl_itr = sizeof(*msg_hdr) + /* Check payload descriptor(s) */
        num_pls * sizeof(msg_hdr->pld[0]);
    pl_itr = ALIGN(pl_itr, I2400M_PL_ALIGN);
    if (pl_itr > skb_len) { /* got all the payload descriptors? */
        dev_err(dev, "RX: HW BUG? message too short (%u bytes) for "
            "%u payload descriptors (%zu each, total %zu)\n",
            skb_len, num_pls, sizeof(msg_hdr->pld[0]), pl_itr);
        goto error_pl_descr_short;
    }
    /* Walk each payload payload--check we really got it */
    for (i = 0; i < num_pls; i++) {
        /* work around old gcc warnings */
        pl_size = i2400m_pld_size(&msg_hdr->pld[i]);
        result = i2400m_rx_pl_descr_check(i2400m, &msg_hdr->pld[i],
                          pl_itr, skb_len);
        if (result < 0)
            goto error_pl_descr_check;
        single_last = num_pls == 1 || i == num_pls - 1;
        i2400m_rx_payload(i2400m, skb, single_last, &msg_hdr->pld[i],
                  skb->data + pl_itr);
        pl_itr += ALIGN(pl_size, I2400M_PL_ALIGN);
        cond_resched();     /* Don't monopolize */
    }
    kfree_skb(skb);
    /* Update device statistics */
    spin_lock_irqsave(&i2400m->rx_lock, flags);
    i2400m->rx_pl_num += i;
    if (i > i2400m->rx_pl_max)
        i2400m->rx_pl_max = i;
    if (i < i2400m->rx_pl_min)
        i2400m->rx_pl_min = i;
    i2400m->rx_num++;
    i2400m->rx_size_acc += skb_len;
    if (skb_len < i2400m->rx_size_min)
        i2400m->rx_size_min = skb_len;
    if (skb_len > i2400m->rx_size_max)
        i2400m->rx_size_max = skb_len;
    spin_unlock_irqrestore(&i2400m->rx_lock, flags);
error_pl_descr_check:
error_pl_descr_short:
error_msg_hdr_check:
    d_fnend(4, dev, "(i2400m %p skb %p [size %u]) = %d\n",
        i2400m, skb, skb_len, result);
    return result;
}
EXPORT_SYMBOL_GPL(i2400m_rx);


void i2400m_unknown_barker(struct i2400m *i2400m,
               const void *buf, size_t size)
{
    struct device *dev = i2400m_dev(i2400m);
    char prefix[64];
    const __le32 *barker = buf;
    dev_err(dev, "RX: HW BUG? unknown barker %08x, "
        "dropping %zu bytes\n", le32_to_cpu(*barker), size);
    snprintf(prefix, sizeof(prefix), "%s %s: ",
         dev_driver_string(dev), dev_name(dev));
    if (size > 64) {
        print_hex_dump(KERN_ERR, prefix, DUMP_PREFIX_OFFSET,
                   8, 4, buf, 64, 0);
        printk(KERN_ERR "%s... (only first 64 bytes "
               "dumped)\n", prefix);
    } else
        print_hex_dump(KERN_ERR, prefix, DUMP_PREFIX_OFFSET,
                   8, 4, buf, size, 0);
}
EXPORT_SYMBOL(i2400m_unknown_barker);


/*
 * 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];
        }
        kref_init(&i2400m->rx_roq_refcount);
    }
    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)
{
    unsigned long flags;

    if (i2400m->rx_reorder) {
        spin_lock_irqsave(&i2400m->rx_lock, flags);
        kref_put(&i2400m->rx_roq_refcount, i2400m_rx_roq_destroy);
        spin_unlock_irqrestore(&i2400m->rx_lock, flags);
    }
    /* at this point, nothing can be received... */
    i2400m_report_hook_flush(i2400m);
}