ar5523: Add new driver

This driver is for the AR5523 chipset from Atheros. It was created
in 2007 by Christoph Hellwig but it was never finished. I found it a
couple of months ago and after some polishing it's working pretty
fine.

The driver was written with the FreeBSD driver (uath) as reference,
which was written with the reverse-engineered windows driver as
reference, hence the feature set is very limited. Station mode
only, no HW crypto offload.

Signed-off-by: Pontus Fuchs <pontus.fuchs@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 1806 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ar5523/ar5523.c b/drivers/net/wireless/ath/ar5523/ar5523.c
new file mode 100644
index 000000000000..f782b6e502bf
--- /dev/null
+++ b/drivers/net/wireless/ath/ar5523/ar5523.c
@@ -0,0 +1,1806 @@
+/*
+ * Copyright (c) 2006 Damien Bergamini <damien.bergamini@free.fr>
+ * Copyright (c) 2006 Sam Leffler, Errno Consulting
+ * Copyright (c) 2007 Christoph Hellwig <hch@lst.de>
+ * Copyright (c) 2008-2009 Weongyo Jeong <weongyo@freebsd.org>
+ * Copyright (c) 2012 Pontus Fuchs <pontus.fuchs@gmail.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * This driver is based on the uath driver written by Damien Bergamini for
+ * OpenBSD, who did black-box analysis of the Windows binary driver to find
+ * out how the hardware works.  It contains a lot magic numbers because of
+ * that and only has minimal functionality.
+ */
+#include <linux/compiler.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/completion.h>
+#include <linux/firmware.h>
+#include <linux/skbuff.h>
+#include <linux/usb.h>
+#include <net/mac80211.h>
+
+#include "ar5523.h"
+#include "ar5523_hw.h"
+
+/*
+ * Various supported device vendors/products.
+ * UB51: AR5005UG 802.11b/g, UB52: AR5005UX 802.11a/b/g
+ */
+
+static int ar5523_submit_rx_cmd(struct ar5523 *ar);
+static void ar5523_data_tx_pkt_put(struct ar5523 *ar);
+
+static void ar5523_read_reply(struct ar5523 *ar, struct ar5523_cmd_hdr *hdr,
+			      struct ar5523_tx_cmd *cmd)
+{
+	int dlen, olen;
+	u32 *rp;
+
+	dlen = hdr->len - sizeof(*hdr);
+
+	if (dlen < 0) {
+		WARN_ON(1);
+		goto out;
+	}
+
+	ar5523_dbg(ar, "Code = %d len = %d\n", hdr->code & 0xff, dlen);
+
+	rp = (u32 *)(hdr + 1);
+	if (dlen >= sizeof(u32)) {
+		olen = be32_to_cpu(rp[0]);
+		dlen -= sizeof(u32);
+		if (olen == 0) {
+			/* convention is 0 =>'s one word */
+			olen = sizeof(u32);
+		}
+	} else
+		olen = 0;
+
+	if (cmd->odata) {
+		if (cmd->olen < olen) {
+			ar5523_err(ar, "olen to small %d < %d\n",
+				   cmd->olen, olen);
+			cmd->olen = 0;
+			cmd->res = -EOVERFLOW;
+		} else {
+			cmd->olen = olen;
+			memcpy(cmd->odata, &rp[1], olen);
+			cmd->res = 0;
+		}
+	}
+
+out:
+	complete(&cmd->done);
+}
+
+static void ar5523_cmd_rx_cb(struct urb *urb)
+{
+	struct ar5523 *ar = urb->context;
+	struct ar5523_tx_cmd *cmd = &ar->tx_cmd;
+	struct ar5523_cmd_hdr *hdr = ar->rx_cmd_buf;
+	int dlen;
+
+	if (urb->status) {
+		if (urb->status != -ESHUTDOWN)
+			ar5523_err(ar, "RX USB error %d.\n", urb->status);
+		goto skip;
+	}
+
+	if (urb->actual_length < sizeof(struct ar5523_cmd_hdr)) {
+		ar5523_err(ar, "RX USB to short.\n");
+		goto skip;
+	}
+
+	ar5523_dbg(ar, "%s code %02x priv %d\n", __func__,
+		   be32_to_cpu(hdr->code) & 0xff, hdr->priv);
+
+	hdr->code = be32_to_cpu(hdr->code);
+	hdr->len = be32_to_cpu(hdr->len);
+
+	switch (hdr->code & 0xff) {
+	default:
+		/* reply to a read command */
+		if (hdr->priv != AR5523_CMD_ID) {
+			ar5523_err(ar, "Unexpected command id: %02x\n",
+				   hdr->code & 0xff);
+			goto skip;
+		}
+		ar5523_read_reply(ar, hdr, cmd);
+		break;
+
+	case WDCMSG_DEVICE_AVAIL:
+		ar5523_dbg(ar, "WDCMSG_DEVICE_AVAIL\n");
+		cmd->res = 0;
+		cmd->olen = 0;
+		complete(&cmd->done);
+		break;
+
+	case WDCMSG_SEND_COMPLETE:
+		ar5523_dbg(ar, "WDCMSG_SEND_COMPLETE: %d pending\n",
+			atomic_read(&ar->tx_nr_pending));
+		if (!test_bit(AR5523_HW_UP, &ar->flags))
+			ar5523_dbg(ar, "Unexpected WDCMSG_SEND_COMPLETE\n");
+		else {
+			mod_timer(&ar->tx_wd_timer,
+				  jiffies + AR5523_TX_WD_TIMEOUT);
+			ar5523_data_tx_pkt_put(ar);
+
+		}
+		break;
+
+	case WDCMSG_TARGET_START:
+		/* This command returns a bogus id so it needs special
+		   handling */
+		dlen = hdr->len - sizeof(*hdr);
+		if (dlen != (int)sizeof(u32)) {
+			ar5523_err(ar, "Invalid reply to WDCMSG_TARGET_START");
+			return;
+		}
+		memcpy(cmd->odata, hdr + 1, sizeof(u32));
+		cmd->olen = sizeof(u32);
+		cmd->res = 0;
+		complete(&cmd->done);
+		break;
+
+	case WDCMSG_STATS_UPDATE:
+		ar5523_dbg(ar, "WDCMSG_STATS_UPDATE\n");
+		break;
+	}
+
+skip:
+	ar5523_submit_rx_cmd(ar);
+}
+
+static int ar5523_alloc_rx_cmd(struct ar5523 *ar)
+{
+	ar->rx_cmd_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!ar->rx_cmd_urb)
+		return -ENOMEM;
+
+	ar->rx_cmd_buf = usb_alloc_coherent(ar->dev, AR5523_MAX_RXCMDSZ,
+					    GFP_KERNEL,
+					    &ar->rx_cmd_urb->transfer_dma);
+	if (!ar->rx_cmd_buf) {
+		usb_free_urb(ar->rx_cmd_urb);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+static void ar5523_cancel_rx_cmd(struct ar5523 *ar)
+{
+	usb_kill_urb(ar->rx_cmd_urb);
+}
+
+static void ar5523_free_rx_cmd(struct ar5523 *ar)
+{
+	usb_free_coherent(ar->dev, AR5523_MAX_RXCMDSZ,
+			  ar->rx_cmd_buf, ar->rx_cmd_urb->transfer_dma);
+	usb_free_urb(ar->rx_cmd_urb);
+}
+
+static int ar5523_submit_rx_cmd(struct ar5523 *ar)
+{
+	int error;
+
+	usb_fill_bulk_urb(ar->rx_cmd_urb, ar->dev,
+			  ar5523_cmd_rx_pipe(ar->dev), ar->rx_cmd_buf,
+			  AR5523_MAX_RXCMDSZ, ar5523_cmd_rx_cb, ar);
+	ar->rx_cmd_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+	error = usb_submit_urb(ar->rx_cmd_urb, GFP_ATOMIC);
+	if (error) {
+		if (error != -ENODEV)
+			ar5523_err(ar, "error %d when submitting rx urb\n",
+				   error);
+		return error;
+	}
+	return 0;
+}
+
+/*
+ * Command submitted cb
+ */
+static void ar5523_cmd_tx_cb(struct urb *urb)
+{
+	struct ar5523_tx_cmd *cmd = urb->context;
+	struct ar5523 *ar = cmd->ar;
+
+	if (urb->status) {
+		ar5523_err(ar, "Failed to TX command. Status = %d\n",
+			   urb->status);
+		cmd->res = urb->status;
+		complete(&cmd->done);
+		return;
+	}
+
+	if (!(cmd->flags & AR5523_CMD_FLAG_READ)) {
+		cmd->res = 0;
+		complete(&cmd->done);
+	}
+}
+
+static int ar5523_cmd(struct ar5523 *ar, u32 code, const void *idata,
+		      int ilen, void *odata, int olen, int flags)
+{
+	struct ar5523_cmd_hdr *hdr;
+	struct ar5523_tx_cmd *cmd = &ar->tx_cmd;
+	int xferlen, error;
+
+	/* always bulk-out a multiple of 4 bytes */
+	xferlen = (sizeof(struct ar5523_cmd_hdr) + ilen + 3) & ~3;
+
+	hdr = (struct ar5523_cmd_hdr *)cmd->buf_tx;
+	memset(hdr, 0, sizeof(struct ar5523_cmd_hdr));
+	hdr->len  = cpu_to_be32(xferlen);
+	hdr->code = cpu_to_be32(code);
+	hdr->priv = AR5523_CMD_ID;
+
+	if (flags & AR5523_CMD_FLAG_MAGIC)
+		hdr->magic = cpu_to_be32(1 << 24);
+	memcpy(hdr + 1, idata, ilen);
+
+	cmd->odata = odata;
+	cmd->olen = olen;
+	cmd->flags = flags;
+
+	ar5523_dbg(ar, "do cmd %02x\n", code);
+
+	usb_fill_bulk_urb(cmd->urb_tx, ar->dev, ar5523_cmd_tx_pipe(ar->dev),
+			  cmd->buf_tx, xferlen, ar5523_cmd_tx_cb, cmd);
+	cmd->urb_tx->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+	error = usb_submit_urb(cmd->urb_tx, GFP_KERNEL);
+	if (error) {
+		ar5523_err(ar, "could not send command 0x%x, error=%d\n",
+			   code, error);
+		return error;
+	}
+
+	if (!wait_for_completion_timeout(&cmd->done, 2 * HZ)) {
+		cmd->odata = NULL;
+		ar5523_err(ar, "timeout waiting for command %02x reply\n",
+			   code);
+		cmd->res = -ETIMEDOUT;
+	}
+	return cmd->res;
+}
+
+static int ar5523_cmd_write(struct ar5523 *ar, u32 code, const void *data,
+			    int len, int flags)
+{
+	flags &= ~AR5523_CMD_FLAG_READ;
+	return ar5523_cmd(ar, code, data, len, NULL, 0, flags);
+}
+
+static int ar5523_cmd_read(struct ar5523 *ar, u32 code, const void *idata,
+			   int ilen, void *odata, int olen, int flags)
+{
+	flags |= AR5523_CMD_FLAG_READ;
+	return ar5523_cmd(ar, code, idata, ilen, odata, olen, flags);
+}
+
+static int ar5523_config(struct ar5523 *ar, u32 reg, u32 val)
+{
+	struct ar5523_write_mac write;
+	int error;
+
+	write.reg = cpu_to_be32(reg);
+	write.len = cpu_to_be32(0);	/* 0 = single write */
+	*(u32 *)write.data = cpu_to_be32(val);
+
+	error = ar5523_cmd_write(ar, WDCMSG_TARGET_SET_CONFIG, &write,
+				 3 * sizeof(u32), 0);
+	if (error != 0)
+		ar5523_err(ar, "could not write register 0x%02x\n", reg);
+	return error;
+}
+
+static int ar5523_config_multi(struct ar5523 *ar, u32 reg, const void *data,
+			       int len)
+{
+	struct ar5523_write_mac write;
+	int error;
+
+	write.reg = cpu_to_be32(reg);
+	write.len = cpu_to_be32(len);
+	memcpy(write.data, data, len);
+
+	/* properly handle the case where len is zero (reset) */
+	error = ar5523_cmd_write(ar, WDCMSG_TARGET_SET_CONFIG, &write,
+	    (len == 0) ? sizeof(u32) : 2 * sizeof(u32) + len, 0);
+	if (error != 0)
+		ar5523_err(ar, "could not write %d bytes to register 0x%02x\n",
+			   len, reg);
+	return error;
+}
+
+static int ar5523_get_status(struct ar5523 *ar, u32 which, void *odata,
+			     int olen)
+{
+	int error;
+
+	which = cpu_to_be32(which);
+	error = ar5523_cmd_read(ar, WDCMSG_TARGET_GET_STATUS,
+	    &which, sizeof(which), odata, olen, AR5523_CMD_FLAG_MAGIC);
+	if (error != 0)
+		ar5523_err(ar, "could not read EEPROM offset 0x%02x\n",
+			   be32_to_cpu(which));
+	return error;
+}
+
+static int ar5523_get_capability(struct ar5523 *ar, u32 cap, u32 *val)
+{
+	int error;
+
+	cap = cpu_to_be32(cap);
+	error = ar5523_cmd_read(ar, WDCMSG_TARGET_GET_CAPABILITY,
+	    &cap, sizeof(cap), val, sizeof(u32), AR5523_CMD_FLAG_MAGIC);
+	if (error != 0) {
+		ar5523_err(ar, "could not read capability %u\n",
+			   be32_to_cpu(cap));
+		return error;
+	}
+	*val = be32_to_cpu(*val);
+	return error;
+}
+
+static int ar5523_get_devcap(struct ar5523 *ar)
+{
+#define	GETCAP(x) do {				\
+	error = ar5523_get_capability(ar, x, &cap);		\
+	if (error != 0)					\
+		return error;				\
+	ar5523_info(ar, "Cap: "			\
+	    "%s=0x%08x\n", #x, cap);	\
+} while (0)
+	int error;
+	u32 cap;
+
+	/* collect device capabilities */
+	GETCAP(CAP_TARGET_VERSION);
+	GETCAP(CAP_TARGET_REVISION);
+	GETCAP(CAP_MAC_VERSION);
+	GETCAP(CAP_MAC_REVISION);
+	GETCAP(CAP_PHY_REVISION);
+	GETCAP(CAP_ANALOG_5GHz_REVISION);
+	GETCAP(CAP_ANALOG_2GHz_REVISION);
+
+	GETCAP(CAP_REG_DOMAIN);
+	GETCAP(CAP_REG_CAP_BITS);
+	GETCAP(CAP_WIRELESS_MODES);
+	GETCAP(CAP_CHAN_SPREAD_SUPPORT);
+	GETCAP(CAP_COMPRESS_SUPPORT);
+	GETCAP(CAP_BURST_SUPPORT);
+	GETCAP(CAP_FAST_FRAMES_SUPPORT);
+	GETCAP(CAP_CHAP_TUNING_SUPPORT);
+	GETCAP(CAP_TURBOG_SUPPORT);
+	GETCAP(CAP_TURBO_PRIME_SUPPORT);
+	GETCAP(CAP_DEVICE_TYPE);
+	GETCAP(CAP_WME_SUPPORT);
+	GETCAP(CAP_TOTAL_QUEUES);
+	GETCAP(CAP_CONNECTION_ID_MAX);
+
+	GETCAP(CAP_LOW_5GHZ_CHAN);
+	GETCAP(CAP_HIGH_5GHZ_CHAN);
+	GETCAP(CAP_LOW_2GHZ_CHAN);
+	GETCAP(CAP_HIGH_2GHZ_CHAN);
+	GETCAP(CAP_TWICE_ANTENNAGAIN_5G);
+	GETCAP(CAP_TWICE_ANTENNAGAIN_2G);
+
+	GETCAP(CAP_CIPHER_AES_CCM);
+	GETCAP(CAP_CIPHER_TKIP);
+	GETCAP(CAP_MIC_TKIP);
+	return 0;
+}
+
+static int ar5523_set_ledsteady(struct ar5523 *ar, int lednum, int ledmode)
+{
+	struct ar5523_cmd_ledsteady led;
+
+	led.lednum = cpu_to_be32(lednum);
+	led.ledmode = cpu_to_be32(ledmode);
+
+	ar5523_dbg(ar, "set %s led %s (steady)\n",
+		   (lednum == UATH_LED_LINK) ? "link" : "activity",
+		   ledmode ? "on" : "off");
+	return ar5523_cmd_write(ar, WDCMSG_SET_LED_STEADY, &led, sizeof(led),
+				 0);
+}
+
+static int ar5523_set_rxfilter(struct ar5523 *ar, u32 bits, u32 op)
+{
+	struct ar5523_cmd_rx_filter rxfilter;
+
+	rxfilter.bits = cpu_to_be32(bits);
+	rxfilter.op = cpu_to_be32(op);
+
+	ar5523_dbg(ar, "setting Rx filter=0x%x flags=0x%x\n", bits, op);
+	return ar5523_cmd_write(ar, WDCMSG_RX_FILTER, &rxfilter,
+				 sizeof(rxfilter), 0);
+}
+
+static int ar5523_reset_tx_queues(struct ar5523 *ar)
+{
+	__be32 qid = cpu_to_be32(0);
+
+	ar5523_dbg(ar, "resetting Tx queue\n");
+	return ar5523_cmd_write(ar, WDCMSG_RELEASE_TX_QUEUE,
+				 &qid, sizeof(qid), 0);
+}
+
+static int ar5523_set_chan(struct ar5523 *ar)
+{
+	struct ieee80211_conf *conf = &ar->hw->conf;
+
+	struct ar5523_cmd_reset reset;
+
+	memset(&reset, 0, sizeof(reset));
+	reset.flags |= cpu_to_be32(UATH_CHAN_2GHZ);
+	reset.flags |= cpu_to_be32(UATH_CHAN_OFDM);
+	reset.freq = cpu_to_be32(conf->channel->center_freq);
+	reset.maxrdpower = cpu_to_be32(50);	/* XXX */
+	reset.channelchange = cpu_to_be32(1);
+	reset.keeprccontent = cpu_to_be32(0);
+
+	ar5523_dbg(ar, "set chan flags 0x%x freq %d\n",
+		   be32_to_cpu(reset.flags),
+		   conf->channel->center_freq);
+	return ar5523_cmd_write(ar, WDCMSG_RESET, &reset, sizeof(reset), 0);
+}
+
+static int ar5523_queue_init(struct ar5523 *ar)
+{
+	struct ar5523_cmd_txq_setup qinfo;
+
+	ar5523_dbg(ar, "setting up Tx queue\n");
+	qinfo.qid	     = cpu_to_be32(0);
+	qinfo.len	     = cpu_to_be32(sizeof(qinfo.attr));
+	qinfo.attr.priority  = cpu_to_be32(0);	/* XXX */
+	qinfo.attr.aifs	     = cpu_to_be32(3);
+	qinfo.attr.logcwmin  = cpu_to_be32(4);
+	qinfo.attr.logcwmax  = cpu_to_be32(10);
+	qinfo.attr.bursttime = cpu_to_be32(0);
+	qinfo.attr.mode	     = cpu_to_be32(0);
+	qinfo.attr.qflags    = cpu_to_be32(1);	/* XXX? */
+	return ar5523_cmd_write(ar, WDCMSG_SETUP_TX_QUEUE, &qinfo,
+				 sizeof(qinfo), 0);
+}
+
+static int ar5523_switch_chan(struct ar5523 *ar)
+{
+	int error;
+
+	error = ar5523_set_chan(ar);
+	if (error) {
+		ar5523_err(ar, "could not set chan, error %d\n", error);
+		goto out_err;
+	}
+
+	/* reset Tx rings */
+	error = ar5523_reset_tx_queues(ar);
+	if (error) {
+		ar5523_err(ar, "could not reset Tx queues, error %d\n",
+			   error);
+		goto out_err;
+	}
+	/* set Tx rings WME properties */
+	error = ar5523_queue_init(ar);
+	if (error)
+		ar5523_err(ar, "could not init wme, error %d\n", error);
+
+out_err:
+	return error;
+}
+
+static void ar5523_rx_data_put(struct ar5523 *ar,
+				struct ar5523_rx_data *data)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&ar->rx_data_list_lock, flags);
+	list_move(&data->list, &ar->rx_data_free);
+	spin_unlock_irqrestore(&ar->rx_data_list_lock, flags);
+}
+
+static void ar5523_data_rx_cb(struct urb *urb)
+{
+	struct ar5523_rx_data *data = urb->context;
+	struct ar5523 *ar = data->ar;
+	struct ar5523_rx_desc *desc;
+	struct ar5523_chunk *chunk;
+	struct ieee80211_hw *hw = ar->hw;
+	struct ieee80211_rx_status *rx_status;
+	u32 rxlen;
+	int usblen = urb->actual_length;
+	int hdrlen, pad;
+
+	ar5523_dbg(ar, "%s\n", __func__);
+	/* sync/async unlink faults aren't errors */
+	if (urb->status) {
+		if (urb->status != -ESHUTDOWN)
+			ar5523_err(ar, "%s: USB err: %d\n", __func__,
+				   urb->status);
+		goto skip;
+	}
+
+	if (usblen < AR5523_MIN_RXBUFSZ) {
+		ar5523_err(ar, "RX: wrong xfer size (usblen=%d)\n", usblen);
+		goto skip;
+	}
+
+	chunk = (struct ar5523_chunk *) data->skb->data;
+
+	if (((chunk->flags & UATH_CFLAGS_FINAL) == 0) ||
+		chunk->seqnum != 0) {
+		ar5523_dbg(ar, "RX: No final flag. s: %d f: %02x l: %d\n",
+			   chunk->seqnum, chunk->flags,
+			   be16_to_cpu(chunk->length));
+		goto skip;
+	}
+
+	/* Rx descriptor is located at the end, 32-bit aligned */
+	desc = (struct ar5523_rx_desc *)
+		(data->skb->data + usblen - sizeof(struct ar5523_rx_desc));
+
+	rxlen = be32_to_cpu(desc->len);
+	if (rxlen > ar->rxbufsz) {
+		ar5523_dbg(ar, "RX: Bad descriptor (len=%d)\n",
+			   be32_to_cpu(desc->len));
+		goto skip;
+	}
+
+	if (!rxlen) {
+		ar5523_dbg(ar, "RX: rxlen is 0\n");
+		goto skip;
+	}
+
+	if (be32_to_cpu(desc->status) != 0) {
+		ar5523_dbg(ar, "Bad RX status (0x%x len = %d). Skip\n",
+			   be32_to_cpu(desc->status), be32_to_cpu(desc->len));
+		goto skip;
+	}
+
+	skb_reserve(data->skb, sizeof(*chunk));
+	skb_put(data->skb, rxlen - sizeof(struct ar5523_rx_desc));
+
+	hdrlen = ieee80211_get_hdrlen_from_skb(data->skb);
+	if (!IS_ALIGNED(hdrlen, 4)) {
+		ar5523_dbg(ar, "eek, alignment workaround activated\n");
+		pad = ALIGN(hdrlen, 4) - hdrlen;
+		memmove(data->skb->data + pad, data->skb->data, hdrlen);
+		skb_pull(data->skb, pad);
+		skb_put(data->skb, pad);
+	}
+
+	rx_status = IEEE80211_SKB_RXCB(data->skb);
+	memset(rx_status, 0, sizeof(*rx_status));
+	rx_status->freq = be32_to_cpu(desc->channel);
+	rx_status->band = hw->conf.channel->band;
+	rx_status->signal = -95 + be32_to_cpu(desc->rssi);
+
+	ieee80211_rx_irqsafe(hw, data->skb);
+	data->skb = NULL;
+
+skip:
+	if (data->skb) {
+		dev_kfree_skb_irq(data->skb);
+		data->skb = NULL;
+	}
+
+	ar5523_rx_data_put(ar, data);
+	if (atomic_inc_return(&ar->rx_data_free_cnt) >=
+	    AR5523_RX_DATA_REFILL_COUNT &&
+	    test_bit(AR5523_HW_UP, &ar->flags))
+		queue_work(ar->wq, &ar->rx_refill_work);
+}
+
+static void ar5523_rx_refill_work(struct work_struct *work)
+{
+	struct ar5523 *ar = container_of(work, struct ar5523, rx_refill_work);
+	struct ar5523_rx_data *data;
+	unsigned long flags;
+	int error;
+
+	ar5523_dbg(ar, "%s\n", __func__);
+	do {
+		spin_lock_irqsave(&ar->rx_data_list_lock, flags);
+
+		if (!list_empty(&ar->rx_data_free))
+			data = (struct ar5523_rx_data *) ar->rx_data_free.next;
+		else
+			data = NULL;
+		spin_unlock_irqrestore(&ar->rx_data_list_lock, flags);
+
+		if (!data)
+			goto done;
+
+		data->skb = alloc_skb(ar->rxbufsz, GFP_KERNEL);
+		if (!data->skb) {
+			ar5523_err(ar, "could not allocate rx skbuff\n");
+			return;
+		}
+
+		usb_fill_bulk_urb(data->urb, ar->dev,
+				  ar5523_data_rx_pipe(ar->dev), data->skb->data,
+				  ar->rxbufsz, ar5523_data_rx_cb, data);
+
+		spin_lock_irqsave(&ar->rx_data_list_lock, flags);
+		list_move(&data->list, &ar->rx_data_used);
+		spin_unlock_irqrestore(&ar->rx_data_list_lock, flags);
+		atomic_dec(&ar->rx_data_free_cnt);
+
+		error = usb_submit_urb(data->urb, GFP_KERNEL);
+		if (error) {
+			kfree_skb(data->skb);
+			if (error != -ENODEV)
+				ar5523_err(ar, "Err sending rx data urb %d\n",
+					   error);
+			ar5523_rx_data_put(ar, data);
+			atomic_inc(&ar->rx_data_free_cnt);
+			return;
+		}
+
+	} while (true);
+done:
+	return;
+}
+
+static void ar5523_cancel_rx_bufs(struct ar5523 *ar)
+{
+	struct ar5523_rx_data *data;
+	unsigned long flags;
+
+	do {
+		spin_lock_irqsave(&ar->rx_data_list_lock, flags);
+		if (!list_empty(&ar->rx_data_used))
+			data = (struct ar5523_rx_data *) ar->rx_data_used.next;
+		else
+			data = NULL;
+		spin_unlock_irqrestore(&ar->rx_data_list_lock, flags);
+
+		if (!data)
+			break;
+
+		usb_kill_urb(data->urb);
+		list_move(&data->list, &ar->rx_data_free);
+		atomic_inc(&ar->rx_data_free_cnt);
+	} while (data);
+}
+
+static void ar5523_free_rx_bufs(struct ar5523 *ar)
+{
+	struct ar5523_rx_data *data;
+
+	ar5523_cancel_rx_bufs(ar);
+	while (!list_empty(&ar->rx_data_free)) {
+		data = (struct ar5523_rx_data *) ar->rx_data_free.next;
+		list_del(&data->list);
+		usb_free_urb(data->urb);
+	}
+}
+
+static int ar5523_alloc_rx_bufs(struct ar5523 *ar)
+{
+	int i;
+
+	for (i = 0; i < AR5523_RX_DATA_COUNT; i++) {
+		struct ar5523_rx_data *data = &ar->rx_data[i];
+
+		data->ar = ar;
+		data->urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!data->urb) {
+			ar5523_err(ar, "could not allocate rx data urb\n");
+			goto err;
+		}
+		list_add_tail(&data->list, &ar->rx_data_free);
+		atomic_inc(&ar->rx_data_free_cnt);
+	}
+	return 0;
+
+err:
+	ar5523_free_rx_bufs(ar);
+	return -ENOMEM;
+}
+
+static void ar5523_data_tx_pkt_put(struct ar5523 *ar)
+{
+	atomic_dec(&ar->tx_nr_total);
+	if (!atomic_dec_return(&ar->tx_nr_pending)) {
+		del_timer(&ar->tx_wd_timer);
+		wake_up(&ar->tx_flush_waitq);
+	}
+
+	if (atomic_read(&ar->tx_nr_total) < AR5523_TX_DATA_RESTART_COUNT) {
+		ar5523_dbg(ar, "restart tx queue\n");
+		ieee80211_wake_queues(ar->hw);
+	}
+}
+
+static void ar5523_data_tx_cb(struct urb *urb)
+{
+	struct sk_buff *skb = urb->context;
+	struct ieee80211_tx_info *txi = IEEE80211_SKB_CB(skb);
+	struct ar5523_tx_data *data = (struct ar5523_tx_data *)
+				       txi->driver_data;
+	struct ar5523 *ar = data->ar;
+	unsigned long flags;
+
+	ar5523_dbg(ar, "data tx urb completed: %d\n", urb->status);
+
+	spin_lock_irqsave(&ar->tx_data_list_lock, flags);
+	list_del(&data->list);
+	spin_unlock_irqrestore(&ar->tx_data_list_lock, flags);
+
+	if (urb->status) {
+		ar5523_dbg(ar, "%s: urb status: %d\n", __func__, urb->status);
+		ar5523_data_tx_pkt_put(ar);
+		ieee80211_free_txskb(ar->hw, skb);
+	} else {
+		skb_pull(skb, sizeof(struct ar5523_tx_desc) + sizeof(__be32));
+		ieee80211_tx_status_irqsafe(ar->hw, skb);
+	}
+	usb_free_urb(urb);
+}
+
+static void ar5523_tx(struct ieee80211_hw *hw,
+		       struct ieee80211_tx_control *control,
+		       struct sk_buff *skb)
+{
+	struct ieee80211_tx_info *txi = IEEE80211_SKB_CB(skb);
+	struct ar5523_tx_data *data = (struct ar5523_tx_data *)
+					txi->driver_data;
+	struct ar5523 *ar = hw->priv;
+	unsigned long flags;
+
+	ar5523_dbg(ar, "tx called\n");
+	if (atomic_inc_return(&ar->tx_nr_total) >= AR5523_TX_DATA_COUNT) {
+		ar5523_dbg(ar, "tx queue full\n");
+		ar5523_dbg(ar, "stop queues (tot %d pend %d)\n",
+			   atomic_read(&ar->tx_nr_total),
+			   atomic_read(&ar->tx_nr_pending));
+		ieee80211_stop_queues(hw);
+	}
+
+	data->skb = skb;
+
+	spin_lock_irqsave(&ar->tx_data_list_lock, flags);
+	list_add_tail(&data->list, &ar->tx_queue_pending);
+	spin_unlock_irqrestore(&ar->tx_data_list_lock, flags);
+
+	ieee80211_queue_work(ar->hw, &ar->tx_work);
+}
+
+static void ar5523_tx_work_locked(struct ar5523 *ar)
+{
+	struct ar5523_tx_data *data;
+	struct ar5523_tx_desc *desc;
+	struct ar5523_chunk *chunk;
+	struct ieee80211_tx_info *txi;
+	struct urb *urb;
+	struct sk_buff *skb;
+	int error = 0, paylen;
+	u32 txqid;
+	unsigned long flags;
+
+	BUILD_BUG_ON(sizeof(struct ar5523_tx_data) >
+		     IEEE80211_TX_INFO_DRIVER_DATA_SIZE);
+
+	ar5523_dbg(ar, "%s\n", __func__);
+	do {
+		spin_lock_irqsave(&ar->tx_data_list_lock, flags);
+		if (!list_empty(&ar->tx_queue_pending)) {
+			data = (struct ar5523_tx_data *)
+				ar->tx_queue_pending.next;
+			list_del(&data->list);
+		} else
+			data = NULL;
+		spin_unlock_irqrestore(&ar->tx_data_list_lock, flags);
+
+		if (!data)
+			break;
+
+		skb = data->skb;
+		txqid = 0;
+		txi = IEEE80211_SKB_CB(skb);
+		paylen = skb->len;
+		urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!urb) {
+			ar5523_err(ar, "Failed to allocate TX urb\n");
+			ieee80211_free_txskb(ar->hw, skb);
+			continue;
+		}
+
+		data->ar = ar;
+		data->urb = urb;
+
+		desc = (struct ar5523_tx_desc *)skb_push(skb, sizeof(*desc));
+		chunk = (struct ar5523_chunk *)skb_push(skb, sizeof(*chunk));
+
+		chunk->seqnum = 0;
+		chunk->flags = UATH_CFLAGS_FINAL;
+		chunk->length = cpu_to_be16(skb->len);
+
+		desc->msglen = cpu_to_be32(skb->len);
+		desc->msgid  = AR5523_DATA_ID;
+		desc->buflen = cpu_to_be32(paylen);
+		desc->type   = cpu_to_be32(WDCMSG_SEND);
+		desc->flags  = cpu_to_be32(UATH_TX_NOTIFY);
+
+		if (test_bit(AR5523_CONNECTED, &ar->flags))
+			desc->connid = cpu_to_be32(AR5523_ID_BSS);
+		else
+			desc->connid = cpu_to_be32(AR5523_ID_BROADCAST);
+
+		if (txi->flags & IEEE80211_TX_CTL_USE_MINRATE)
+			txqid |= UATH_TXQID_MINRATE;
+
+		desc->txqid = cpu_to_be32(txqid);
+
+		urb->transfer_flags = URB_ZERO_PACKET;
+		usb_fill_bulk_urb(urb, ar->dev, ar5523_data_tx_pipe(ar->dev),
+				  skb->data, skb->len, ar5523_data_tx_cb, skb);
+
+		spin_lock_irqsave(&ar->tx_data_list_lock, flags);
+		list_add_tail(&data->list, &ar->tx_queue_submitted);
+		spin_unlock_irqrestore(&ar->tx_data_list_lock, flags);
+		mod_timer(&ar->tx_wd_timer, jiffies + AR5523_TX_WD_TIMEOUT);
+		atomic_inc(&ar->tx_nr_pending);
+
+		ar5523_dbg(ar, "TX Frame (%d pending)\n",
+			   atomic_read(&ar->tx_nr_pending));
+		error = usb_submit_urb(urb, GFP_KERNEL);
+		if (error) {
+			ar5523_err(ar, "error %d when submitting tx urb\n",
+				   error);
+			spin_lock_irqsave(&ar->tx_data_list_lock, flags);
+			list_del(&data->list);
+			spin_unlock_irqrestore(&ar->tx_data_list_lock, flags);
+			atomic_dec(&ar->tx_nr_pending);
+			ar5523_data_tx_pkt_put(ar);
+			usb_free_urb(urb);
+			ieee80211_free_txskb(ar->hw, skb);
+		}
+	} while (true);
+}
+
+static void ar5523_tx_work(struct work_struct *work)
+{
+	struct ar5523 *ar = container_of(work, struct ar5523, tx_work);
+
+	ar5523_dbg(ar, "%s\n", __func__);
+	mutex_lock(&ar->mutex);
+	ar5523_tx_work_locked(ar);
+	mutex_unlock(&ar->mutex);
+}
+
+static void ar5523_tx_wd_timer(unsigned long arg)
+{
+	struct ar5523 *ar = (struct ar5523 *) arg;
+
+	ar5523_dbg(ar, "TX watchdog timer triggered\n");
+	ieee80211_queue_work(ar->hw, &ar->tx_wd_work);
+}
+
+static void ar5523_tx_wd_work(struct work_struct *work)
+{
+	struct ar5523 *ar = container_of(work, struct ar5523, tx_wd_work);
+
+	/* Occasionally the TX queues stop responding. The only way to
+	 * recover seems to be to reset the dongle.
+	 */
+
+	mutex_lock(&ar->mutex);
+	ar5523_err(ar, "TX queue stuck (tot %d pend %d)\n",
+		   atomic_read(&ar->tx_nr_total),
+		   atomic_read(&ar->tx_nr_pending));
+
+	ar5523_err(ar, "Will restart dongle.\n");
+	ar5523_cmd_write(ar, WDCMSG_TARGET_RESET, NULL, 0, 0);
+	mutex_unlock(&ar->mutex);
+}
+
+static void ar5523_flush_tx(struct ar5523 *ar)
+{
+	ar5523_tx_work_locked(ar);
+
+	/* Don't waste time trying to flush if USB is disconnected */
+	if (test_bit(AR5523_USB_DISCONNECTED, &ar->flags))
+		return;
+	if (!wait_event_timeout(ar->tx_flush_waitq,
+	    !atomic_read(&ar->tx_nr_pending), AR5523_FLUSH_TIMEOUT))
+		ar5523_err(ar, "flush timeout (tot %d pend %d)\n",
+			   atomic_read(&ar->tx_nr_total),
+			   atomic_read(&ar->tx_nr_pending));
+}
+
+static void ar5523_free_tx_cmd(struct ar5523 *ar)
+{
+	struct ar5523_tx_cmd *cmd = &ar->tx_cmd;
+
+	usb_free_coherent(ar->dev, AR5523_MAX_RXCMDSZ, cmd->buf_tx,
+			  cmd->urb_tx->transfer_dma);
+	usb_free_urb(cmd->urb_tx);
+}
+
+static int ar5523_alloc_tx_cmd(struct ar5523 *ar)
+{
+	struct ar5523_tx_cmd *cmd = &ar->tx_cmd;
+
+	cmd->ar = ar;
+	init_completion(&cmd->done);
+
+	cmd->urb_tx = usb_alloc_urb(0, GFP_KERNEL);
+	if (!cmd->urb_tx) {
+		ar5523_err(ar, "could not allocate urb\n");
+		return -ENOMEM;
+	}
+	cmd->buf_tx = usb_alloc_coherent(ar->dev, AR5523_MAX_TXCMDSZ,
+					 GFP_KERNEL,
+					 &cmd->urb_tx->transfer_dma);
+	if (!cmd->buf_tx) {
+		usb_free_urb(cmd->urb_tx);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+/*
+ * This function is called periodically (every second) when associated to
+ * query device statistics.
+ */
+static void ar5523_stat_work(struct work_struct *work)
+{
+	struct ar5523 *ar = container_of(work, struct ar5523, stat_work.work);
+	int error;
+
+	ar5523_dbg(ar, "%s\n", __func__);
+	mutex_lock(&ar->mutex);
+
+	/*
+	 * Send request for statistics asynchronously once a second. This
+	 * seems to be important. Throughput is a lot better if this is done.
+	 */
+	error = ar5523_cmd_write(ar, WDCMSG_TARGET_GET_STATS, NULL, 0, 0);
+	if (error)
+		ar5523_err(ar, "could not query stats, error %d\n", error);
+	mutex_unlock(&ar->mutex);
+	ieee80211_queue_delayed_work(ar->hw, &ar->stat_work, HZ);
+}
+
+/*
+ * Interface routines to the mac80211 stack.
+ */
+static int ar5523_start(struct ieee80211_hw *hw)
+{
+	struct ar5523 *ar = hw->priv;
+	int error;
+	__be32 val;
+
+	ar5523_dbg(ar, "start called\n");
+
+	mutex_lock(&ar->mutex);
+	val = cpu_to_be32(0);
+	ar5523_cmd_write(ar, WDCMSG_BIND, &val, sizeof(val), 0);
+
+	/* set MAC address */
+	ar5523_config_multi(ar, CFG_MAC_ADDR, &ar->hw->wiphy->perm_addr,
+			    ETH_ALEN);
+
+	/* XXX honor net80211 state */
+	ar5523_config(ar, CFG_RATE_CONTROL_ENABLE, 0x00000001);
+	ar5523_config(ar, CFG_DIVERSITY_CTL, 0x00000001);
+	ar5523_config(ar, CFG_ABOLT, 0x0000003f);
+	ar5523_config(ar, CFG_WME_ENABLED, 0x00000000);
+
+	ar5523_config(ar, CFG_SERVICE_TYPE, 1);
+	ar5523_config(ar, CFG_TP_SCALE, 0x00000000);
+	ar5523_config(ar, CFG_TPC_HALF_DBM5, 0x0000003c);
+	ar5523_config(ar, CFG_TPC_HALF_DBM2, 0x0000003c);
+	ar5523_config(ar, CFG_OVERRD_TX_POWER, 0x00000000);
+	ar5523_config(ar, CFG_GMODE_PROTECTION, 0x00000000);
+	ar5523_config(ar, CFG_GMODE_PROTECT_RATE_INDEX, 0x00000003);
+	ar5523_config(ar, CFG_PROTECTION_TYPE, 0x00000000);
+	ar5523_config(ar, CFG_MODE_CTS, 0x00000002);
+
+	error = ar5523_cmd_read(ar, WDCMSG_TARGET_START, NULL, 0,
+	    &val, sizeof(val), AR5523_CMD_FLAG_MAGIC);
+	if (error) {
+		ar5523_dbg(ar, "could not start target, error %d\n", error);
+		goto err;
+	}
+	ar5523_dbg(ar, "WDCMSG_TARGET_START returns handle: 0x%x\n",
+		   be32_to_cpu(val));
+
+	ar5523_switch_chan(ar);
+
+	val = cpu_to_be32(TARGET_DEVICE_AWAKE);
+	ar5523_cmd_write(ar, WDCMSG_SET_PWR_MODE, &val, sizeof(val), 0);
+	/* XXX? check */
+	ar5523_cmd_write(ar, WDCMSG_RESET_KEY_CACHE, NULL, 0, 0);
+
+	set_bit(AR5523_HW_UP, &ar->flags);
+	queue_work(ar->wq, &ar->rx_refill_work);
+
+	/* enable Rx */
+	ar5523_set_rxfilter(ar, 0, UATH_FILTER_OP_INIT);
+	ar5523_set_rxfilter(ar,
+			    UATH_FILTER_RX_UCAST | UATH_FILTER_RX_MCAST |
+			    UATH_FILTER_RX_BCAST | UATH_FILTER_RX_BEACON,
+			    UATH_FILTER_OP_SET);
+
+	ar5523_set_ledsteady(ar, UATH_LED_ACTIVITY, UATH_LED_ON);
+	ar5523_dbg(ar, "start OK\n");
+
+err:
+	mutex_unlock(&ar->mutex);
+	return error;
+}
+
+static void ar5523_stop(struct ieee80211_hw *hw)
+{
+	struct ar5523 *ar = hw->priv;
+
+	ar5523_dbg(ar, "stop called\n");
+
+	cancel_delayed_work_sync(&ar->stat_work);
+	mutex_lock(&ar->mutex);
+	clear_bit(AR5523_HW_UP, &ar->flags);
+
+	ar5523_set_ledsteady(ar, UATH_LED_LINK, UATH_LED_OFF);
+	ar5523_set_ledsteady(ar, UATH_LED_ACTIVITY, UATH_LED_OFF);
+
+	ar5523_cmd_write(ar, WDCMSG_TARGET_STOP, NULL, 0, 0);
+
+	del_timer_sync(&ar->tx_wd_timer);
+	cancel_work_sync(&ar->tx_wd_work);
+	cancel_work_sync(&ar->rx_refill_work);
+	ar5523_cancel_rx_bufs(ar);
+	mutex_unlock(&ar->mutex);
+}
+
+static int ar5523_set_rts_threshold(struct ieee80211_hw *hw, u32 value)
+{
+	struct ar5523 *ar = hw->priv;
+	int ret;
+
+	ar5523_dbg(ar, "set_rts_threshold called\n");
+	mutex_lock(&ar->mutex);
+
+	ret = ar5523_config(ar, CFG_USER_RTS_THRESHOLD, value);
+
+	mutex_unlock(&ar->mutex);
+	return ret;
+}
+
+static void ar5523_flush(struct ieee80211_hw *hw, bool drop)
+{
+	struct ar5523 *ar = hw->priv;
+
+	ar5523_dbg(ar, "flush called\n");
+	ar5523_flush_tx(ar);
+}
+
+static int ar5523_add_interface(struct ieee80211_hw *hw,
+				struct ieee80211_vif *vif)
+{
+	struct ar5523 *ar = hw->priv;
+
+	ar5523_dbg(ar, "add interface called\n");
+
+	if (ar->vif) {
+		ar5523_dbg(ar, "invalid add_interface\n");
+		return -EOPNOTSUPP;
+	}
+
+	switch (vif->type) {
+	case NL80211_IFTYPE_STATION:
+		ar->vif = vif;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static void ar5523_remove_interface(struct ieee80211_hw *hw,
+				    struct ieee80211_vif *vif)
+{
+	struct ar5523 *ar = hw->priv;
+
+	ar5523_dbg(ar, "remove interface called\n");
+	ar->vif = NULL;
+}
+
+static int ar5523_hwconfig(struct ieee80211_hw *hw, u32 changed)
+{
+	struct ar5523 *ar = hw->priv;
+
+	ar5523_dbg(ar, "config called\n");
+	mutex_lock(&ar->mutex);
+	if (changed & IEEE80211_CONF_CHANGE_CHANNEL) {