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>

MAINTAINERS

@@ -7477,6 +7477,12 @@ S:	Maintained
 F:	Documentation/usb/acm.txt
 F:	drivers/usb/class/cdc-acm.*
 
+USB AR5523 WIRELESS DRIVER
+M:	Pontus Fuchs <pontus.fuchs@gmail.com>
+L:	linux-wireless@vger.kernel.org
+S:	Maintained
+F:	drivers/net/wireless/ath/ar5523/
+
 USB ATTACHED SCSI
 M:	Matthew Wilcox <willy@linux.intel.com>
 M:	Sarah Sharp <sarah.a.sharp@linux.intel.com>

drivers/net/wireless/ath/Kconfig

@@ -26,5 +26,6 @@ source "drivers/net/wireless/ath/ath5k/Kconfig"
 source "drivers/net/wireless/ath/ath9k/Kconfig"
 source "drivers/net/wireless/ath/carl9170/Kconfig"
 source "drivers/net/wireless/ath/ath6kl/Kconfig"
+source "drivers/net/wireless/ath/ar5523/Kconfig"
 
 endif

drivers/net/wireless/ath/Makefile

@@ -2,6 +2,7 @@ obj-$(CONFIG_ATH5K)		+= ath5k/
 obj-$(CONFIG_ATH9K_HW)		+= ath9k/
 obj-$(CONFIG_CARL9170)		+= carl9170/
 obj-$(CONFIG_ATH6KL)		+= ath6kl/
+obj-$(CONFIG_AR5523)		+= ar5523/
 
 obj-$(CONFIG_ATH_COMMON)	+= ath.o
 

drivers/net/wireless/ath/ar5523/Kconfig

+config AR5523
+       tristate "Atheros AR5523 wireless driver support"
+       depends on MAC80211 && USB
+       select FW_LOADER
+       ---help---
+         This module add support for AR5523 based USB dongles such as D-Link
+         DWL-G132, Netgear WPN111 and many more.

drivers/net/wireless/ath/ar5523/Makefile

+obj-$(CONFIG_AR5523)   := ar5523.o

drivers/net/wireless/ath/ar5523/ar5523.h

+/*
+ * 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.
+ */
+
+#define AR5523_FLAG_PRE_FIRMWARE	(1 << 0)
+#define AR5523_FLAG_ABG			(1 << 1)
+
+#define AR5523_FIRMWARE_FILE	"ar5523.bin"
+
+#define AR5523_CMD_TX_PIPE	0x01
+#define	AR5523_DATA_TX_PIPE	0x02
+#define	AR5523_CMD_RX_PIPE	0x81
+#define	AR5523_DATA_RX_PIPE	0x82
+
+#define ar5523_cmd_tx_pipe(dev) \
+	usb_sndbulkpipe((dev), AR5523_CMD_TX_PIPE)
+#define ar5523_data_tx_pipe(dev) \
+	usb_sndbulkpipe((dev), AR5523_DATA_TX_PIPE)
+#define ar5523_cmd_rx_pipe(dev) \
+	usb_rcvbulkpipe((dev), AR5523_CMD_RX_PIPE)
+#define ar5523_data_rx_pipe(dev) \
+	usb_rcvbulkpipe((dev), AR5523_DATA_RX_PIPE)
+
+#define	AR5523_DATA_TIMEOUT	10000
+#define	AR5523_CMD_TIMEOUT	1000
+
+#define AR5523_TX_DATA_COUNT		8
+#define AR5523_TX_DATA_RESTART_COUNT	2
+#define AR5523_RX_DATA_COUNT		16
+#define AR5523_RX_DATA_REFILL_COUNT	8
+
+#define AR5523_CMD_ID	1
+#define AR5523_DATA_ID	2
+
+#define AR5523_TX_WD_TIMEOUT	(HZ * 2)
+#define AR5523_FLUSH_TIMEOUT	(HZ * 3)
+
+enum AR5523_flags {
+	AR5523_HW_UP,
+	AR5523_USB_DISCONNECTED,
+	AR5523_CONNECTED
+};
+
+struct ar5523_tx_cmd {
+	struct ar5523		*ar;
+	struct urb		*urb_tx;
+	void			*buf_tx;
+	void			*odata;
+	int			olen;
+	int			flags;
+	int			res;
+	struct completion	done;
+};
+
+/* This struct is placed in tx_info->driver_data. It must not be larger
+ *  than IEEE80211_TX_INFO_DRIVER_DATA_SIZE.
+ */
+struct ar5523_tx_data {
+	struct list_head	list;
+	struct ar5523		*ar;
+	struct sk_buff		*skb;
+	struct urb		*urb;
+};
+
+struct ar5523_rx_data {
+	struct	list_head	list;
+	struct ar5523		*ar;
+	struct urb		*urb;
+	struct sk_buff		*skb;
+};
+
+struct ar5523 {
+	struct usb_device	*dev;
+	struct ieee80211_hw	*hw;
+
+	unsigned long		flags;
+	struct mutex		mutex;
+	struct workqueue_struct *wq;
+
+	struct ar5523_tx_cmd	tx_cmd;
+
+	struct delayed_work	stat_work;
+
+	struct timer_list	tx_wd_timer;
+	struct work_struct	tx_wd_work;
+	struct work_struct	tx_work;
+	struct list_head	tx_queue_pending;
+	struct list_head	tx_queue_submitted;
+	spinlock_t		tx_data_list_lock;
+	wait_queue_head_t	tx_flush_waitq;
+
+	/* Queued + Submitted TX frames */
+	atomic_t		tx_nr_total;
+
+	/* Submitted TX frames */
+	atomic_t		tx_nr_pending;
+
+	void			*rx_cmd_buf;
+	struct urb		*rx_cmd_urb;
+
+	struct ar5523_rx_data	rx_data[AR5523_RX_DATA_COUNT];
+	spinlock_t		rx_data_list_lock;
+	struct list_head	rx_data_free;
+	struct list_head	rx_data_used;
+	atomic_t		rx_data_free_cnt;
+
+	struct work_struct	rx_refill_work;
+
+	int			rxbufsz;
+	u8			serial[16];
+
+	struct ieee80211_channel channels[14];
+	struct ieee80211_rate	rates[12];
+	struct ieee80211_supported_band band;
+	struct ieee80211_vif	*vif;
+};
+
+/* flags for sending firmware commands */
+#define AR5523_CMD_FLAG_READ	(1 << 1)
+#define AR5523_CMD_FLAG_MAGIC	(1 << 2)
+
+#define ar5523_dbg(ar, format, arg...) \
+	dev_dbg(&(ar)->dev->dev, format, ## arg)
+
+/* On USB hot-unplug there can be a lot of URBs in flight and they'll all
+ * fail. Instead of dealing with them in every possible place just surpress
+ * any messages on USB disconnect.
+ */
+#define ar5523_err(ar, format, arg...) \
+do { \
+	if (!test_bit(AR5523_USB_DISCONNECTED, &ar->flags)) { \
+		dev_err(&(ar)->dev->dev, format, ## arg); \
+	} \
+} while (0)
+#define ar5523_info(ar, format, arg...)	\
+	dev_info(&(ar)->dev->dev, format, ## arg)