Initial import

1 files changed, 1396 insertions, 0 deletions

diff --git a/drivers/net/wimax/i2400m/rx.c b/drivers/net/wimax/i2400m/rx.c
new file mode 100644
index 000000000..0b602951f
--- /dev/null
+++ b/drivers/net/wimax/i2400m/rx.c
@@ -0,0 +1,1396 @@
+/*
+ * 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 <linux-wimax@intel.com>
+ * Yanir Lubetkin <yanirx.lubetkin@intel.com>
+ *  - Initial implementation
+ * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
+ *  - 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;
+}
+
+
+/**
+ * i2400m_rx - Receive a buffer of data from the device
+ *
+ * @i2400m: device descriptor
+ * @skb: skbuff where the data has been received
+ *
+ * Parse in a buffer of data that contains an RX message sent from the
+ * device. See the file header for the format. Run all checks on the
+ * buffer header, then run over each payload's descriptors, verify
+ * their consistency and act on each payload's contents.  If
+ * everything is successful, update the device's statistics.
+ *
+ * Note: You need to set the skb to contain only the length of the
+ * received buffer; for that, use skb_trim(skb, RECEIVED_SIZE).
+ *
+ * Returns:
+ *
+ * 0 if ok, < 0 errno on error
+ *
+ * If ok, this function owns now the skb and the caller DOESN'T have
+ * to run kfree_skb() on it. However, on error, the caller still owns
+ * the skb and it is responsible for releasing it.
+ */
+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;
+
+	i2400m->rx_reorder = i2400m_rx_reorder_disabled? 0 : 1;
+	if (i2400m->rx_reorder) {
+		unsigned itr;
+		struct i2400m_roq_log *rd;
+
+		result = -ENOMEM;
+
+		i2400m->rx_roq = kcalloc(I2400M_RO_CIN + 1,
+					 sizeof(i2400m->rx_roq[0]), GFP_KERNEL);
+		if (i2400m->rx_roq == NULL)
+			goto error_roq_alloc;
+
+		rd = kcalloc(I2400M_RO_CIN + 1, sizeof(*i2400m->rx_roq[0].log),
+			     GFP_KERNEL);
+		if (rd == NULL) {
+			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);
+}