drivers/net/wireless/ath/ath9k/common.c - linux - Git at Google

 /*
  * Copyright (c) 2009 Atheros Communications Inc.
  *
  * 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.
  */

 /*
  * Module for common driver code between ath9k and ath9k_htc
  */

 #include <linux/kernel.h>
 #include <linux/module.h>

 #include "common.h"

 MODULE_AUTHOR("Atheros Communications");
 MODULE_DESCRIPTION("Shared library for Atheros wireless 802.11n LAN cards.");
 MODULE_LICENSE("Dual BSD/GPL");

 /* Common RX processing */

 /* Assumes you've already done the endian to CPU conversion */
 static bool ath9k_rx_accept(struct ath_common *common,
 			    struct sk_buff *skb,
 			    struct ieee80211_rx_status *rxs,
 			    struct ath_rx_status *rx_stats,
 			    bool *decrypt_error)
 {
 	struct ath_hw *ah = common->ah;
 	struct ieee80211_hdr *hdr;
 	__le16 fc;

 	hdr = (struct ieee80211_hdr *) skb->data;
 	fc = hdr->frame_control;

 	if (!rx_stats->rs_datalen)
 		return false;
         /*
          * rs_status follows rs_datalen so if rs_datalen is too large
          * we can take a hint that hardware corrupted it, so ignore
          * those frames.
          */
 	if (rx_stats->rs_datalen > common->rx_bufsize)
 		return false;

 	/*
 	 * rs_more indicates chained descriptors which can be used
 	 * to link buffers together for a sort of scatter-gather
 	 * operation.
 	 *
 	 * The rx_stats->rs_status will not be set until the end of the
 	 * chained descriptors so it can be ignored if rs_more is set. The
 	 * rs_more will be false at the last element of the chained
 	 * descriptors.
 	 */
 	if (!rx_stats->rs_more && rx_stats->rs_status != 0) {
 		if (rx_stats->rs_status & ATH9K_RXERR_CRC)
 			rxs->flag |= RX_FLAG_FAILED_FCS_CRC;
 		if (rx_stats->rs_status & ATH9K_RXERR_PHY)
 			return false;

 		if (rx_stats->rs_status & ATH9K_RXERR_DECRYPT) {
 			*decrypt_error = true;
 		} else if (rx_stats->rs_status & ATH9K_RXERR_MIC) {
 			if (ieee80211_is_ctl(fc))
 				/*
 				 * Sometimes, we get invalid
 				 * MIC failures on valid control frames.
 				 * Remove these mic errors.
 				 */
 				rx_stats->rs_status &= ~ATH9K_RXERR_MIC;
 			else
 				rxs->flag |= RX_FLAG_MMIC_ERROR;
 		}
 		/*
 		 * Reject error frames with the exception of
 		 * decryption and MIC failures. For monitor mode,
 		 * we also ignore the CRC error.
 		 */
 		if (ah->opmode == NL80211_IFTYPE_MONITOR) {
 			if (rx_stats->rs_status &
 			    ~(ATH9K_RXERR_DECRYPT | ATH9K_RXERR_MIC |
 			      ATH9K_RXERR_CRC))
 				return false;
 		} else {
 			if (rx_stats->rs_status &
 			    ~(ATH9K_RXERR_DECRYPT | ATH9K_RXERR_MIC)) {
 				return false;
 			}
 		}
 	}
 	return true;
 }

 static u8 ath9k_process_rate(struct ath_common *common,
 			     struct ieee80211_hw *hw,
 			     struct ath_rx_status *rx_stats,
 			     struct ieee80211_rx_status *rxs,
 			     struct sk_buff *skb)
 {
 	struct ieee80211_supported_band *sband;
 	enum ieee80211_band band;
 	unsigned int i = 0;

 	band = hw->conf.channel->band;
 	sband = hw->wiphy->bands[band];

 	if (rx_stats->rs_rate & 0x80) {
 		/* HT rate */
 		rxs->flag |= RX_FLAG_HT;
 		if (rx_stats->rs_flags & ATH9K_RX_2040)
 			rxs->flag |= RX_FLAG_40MHZ;
 		if (rx_stats->rs_flags & ATH9K_RX_GI)
 			rxs->flag |= RX_FLAG_SHORT_GI;
 		return rx_stats->rs_rate & 0x7f;
 	}

 	for (i = 0; i < sband->n_bitrates; i++) {
 		if (sband->bitrates[i].hw_value == rx_stats->rs_rate)
 			return i;
 		if (sband->bitrates[i].hw_value_short == rx_stats->rs_rate) {
 			rxs->flag |= RX_FLAG_SHORTPRE;
 			return i;
 		}
 	}

 	/* No valid hardware bitrate found -- we should not get here */
 	ath_print(common, ATH_DBG_XMIT, "unsupported hw bitrate detected "
 		  "0x%02x using 1 Mbit\n", rx_stats->rs_rate);
 	if ((common->debug_mask & ATH_DBG_XMIT))
 		print_hex_dump_bytes("", DUMP_PREFIX_NONE, skb->data, skb->len);

         return 0;
 }

 static void ath9k_process_rssi(struct ath_common *common,
 			       struct ieee80211_hw *hw,
 			       struct sk_buff *skb,
 			       struct ath_rx_status *rx_stats)
 {
 	struct ath_hw *ah = common->ah;
 	struct ieee80211_sta *sta;
 	struct ieee80211_hdr *hdr;
 	struct ath_node *an;
 	int last_rssi = ATH_RSSI_DUMMY_MARKER;
 	__le16 fc;

 	hdr = (struct ieee80211_hdr *)skb->data;
 	fc = hdr->frame_control;

 	rcu_read_lock();
 	/*
 	 * XXX: use ieee80211_find_sta! This requires quite a bit of work
 	 * under the current ath9k virtual wiphy implementation as we have
 	 * no way of tying a vif to wiphy. Typically vifs are attached to
 	 * at least one sdata of a wiphy on mac80211 but with ath9k virtual
 	 * wiphy you'd have to iterate over every wiphy and each sdata.
 	 */
 	sta = ieee80211_find_sta_by_hw(hw, hdr->addr2);
 	if (sta) {
 		an = (struct ath_node *) sta->drv_priv;
 		if (rx_stats->rs_rssi != ATH9K_RSSI_BAD &&
 		   !rx_stats->rs_moreaggr)
 			ATH_RSSI_LPF(an->last_rssi, rx_stats->rs_rssi);
 		last_rssi = an->last_rssi;
 	}
 	rcu_read_unlock();

 	if (likely(last_rssi != ATH_RSSI_DUMMY_MARKER))
 		rx_stats->rs_rssi = ATH_EP_RND(last_rssi,
 					      ATH_RSSI_EP_MULTIPLIER);
 	if (rx_stats->rs_rssi < 0)
 		rx_stats->rs_rssi = 0;

 	/* Update Beacon RSSI, this is used by ANI. */
 	if (ieee80211_is_beacon(fc))
 		ah->stats.avgbrssi = rx_stats->rs_rssi;
 }

 /*
  * For Decrypt or Demic errors, we only mark packet status here and always push
  * up the frame up to let mac80211 handle the actual error case, be it no
  * decryption key or real decryption error. This let us keep statistics there.
  */
 int ath9k_cmn_rx_skb_preprocess(struct ath_common *common,
 				struct ieee80211_hw *hw,
 				struct sk_buff *skb,
 				struct ath_rx_status *rx_stats,
 				struct ieee80211_rx_status *rx_status,
 				bool *decrypt_error)
 {
 	struct ath_hw *ah = common->ah;

 	memset(rx_status, 0, sizeof(struct ieee80211_rx_status));
 	if (!ath9k_rx_accept(common, skb, rx_status, rx_stats, decrypt_error))
 		return -EINVAL;

 	ath9k_process_rssi(common, hw, skb, rx_stats);

 	rx_status->rate_idx = ath9k_process_rate(common, hw,
 						 rx_stats, rx_status, skb);
 	rx_status->mactime = ath9k_hw_extend_tsf(ah, rx_stats->rs_tstamp);
 	rx_status->band = hw->conf.channel->band;
 	rx_status->freq = hw->conf.channel->center_freq;
 	rx_status->noise = common->ani.noise_floor;
 	rx_status->signal = ATH_DEFAULT_NOISE_FLOOR + rx_stats->rs_rssi;
 	rx_status->antenna = rx_stats->rs_antenna;
 	rx_status->flag |= RX_FLAG_TSFT;

 	return 0;
 }
 EXPORT_SYMBOL(ath9k_cmn_rx_skb_preprocess);

 void ath9k_cmn_rx_skb_postprocess(struct ath_common *common,
 				  struct sk_buff *skb,
 				  struct ath_rx_status *rx_stats,
 				  struct ieee80211_rx_status *rxs,
 				  bool decrypt_error)
 {
 	struct ath_hw *ah = common->ah;
 	struct ieee80211_hdr *hdr;
 	int hdrlen, padpos, padsize;
 	u8 keyix;
 	__le16 fc;

 	/* see if any padding is done by the hw and remove it */
 	hdr = (struct ieee80211_hdr *) skb->data;
 	hdrlen = ieee80211_get_hdrlen_from_skb(skb);
 	fc = hdr->frame_control;
 	padpos = ath9k_cmn_padpos(hdr->frame_control);

 	/* The MAC header is padded to have 32-bit boundary if the
 	 * packet payload is non-zero. The general calculation for
 	 * padsize would take into account odd header lengths:
 	 * padsize = (4 - padpos % 4) % 4; However, since only
 	 * even-length headers are used, padding can only be 0 or 2
 	 * bytes and we can optimize this a bit. In addition, we must
 	 * not try to remove padding from short control frames that do
 	 * not have payload. */
 	padsize = padpos & 3;
 	if (padsize && skb->len>=padpos+padsize+FCS_LEN) {
 		memmove(skb->data + padsize, skb->data, padpos);
 		skb_pull(skb, padsize);
 	}

 	keyix = rx_stats->rs_keyix;

 	if (!(keyix == ATH9K_RXKEYIX_INVALID) && !decrypt_error) {
 		rxs->flag |= RX_FLAG_DECRYPTED;
 	} else if (ieee80211_has_protected(fc)
 		   && !decrypt_error && skb->len >= hdrlen + 4) {
 		keyix = skb->data[hdrlen + 3] >> 6;

 		if (test_bit(keyix, common->keymap))
 			rxs->flag |= RX_FLAG_DECRYPTED;
 	}
 	if (ah->sw_mgmt_crypto &&
 	    (rxs->flag & RX_FLAG_DECRYPTED) &&
 	    ieee80211_is_mgmt(fc))
 		/* Use software decrypt for management frames. */
 		rxs->flag &= ~RX_FLAG_DECRYPTED;
 }
 EXPORT_SYMBOL(ath9k_cmn_rx_skb_postprocess);

 int ath9k_cmn_padpos(__le16 frame_control)
 {
 	int padpos = 24;
 	if (ieee80211_has_a4(frame_control)) {
 		padpos += ETH_ALEN;
 	}
 	if (ieee80211_is_data_qos(frame_control)) {
 		padpos += IEEE80211_QOS_CTL_LEN;
 	}

 	return padpos;
 }
 EXPORT_SYMBOL(ath9k_cmn_padpos);

 static int __init ath9k_cmn_init(void)
 {
 	return 0;
 }
 module_init(ath9k_cmn_init);

 static void __exit ath9k_cmn_exit(void)
 {
 	return;
 }
 module_exit(ath9k_cmn_exit);
	/*
	* Copyright (c) 2009 Atheros Communications Inc.
	*
	* 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.
	*/

	/*
	* Module for common driver code between ath9k and ath9k_htc
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>

	#include "common.h"

	MODULE_AUTHOR("Atheros Communications");
	MODULE_DESCRIPTION("Shared library for Atheros wireless 802.11n LAN cards.");
	MODULE_LICENSE("Dual BSD/GPL");

	/* Common RX processing */

	/* Assumes you've already done the endian to CPU conversion */
	static bool ath9k_rx_accept(struct ath_common *common,
	struct sk_buff *skb,
	struct ieee80211_rx_status *rxs,
	struct ath_rx_status *rx_stats,
	bool *decrypt_error)
	{
	struct ath_hw *ah = common->ah;
	struct ieee80211_hdr *hdr;
	__le16 fc;

	hdr = (struct ieee80211_hdr *) skb->data;
	fc = hdr->frame_control;

	if (!rx_stats->rs_datalen)
	return false;
	/*
	* rs_status follows rs_datalen so if rs_datalen is too large
	* we can take a hint that hardware corrupted it, so ignore
	* those frames.
	*/
	if (rx_stats->rs_datalen > common->rx_bufsize)
	return false;

	/*
	* rs_more indicates chained descriptors which can be used
	* to link buffers together for a sort of scatter-gather
	* operation.
	*
	* The rx_stats->rs_status will not be set until the end of the
	* chained descriptors so it can be ignored if rs_more is set. The
	* rs_more will be false at the last element of the chained
	* descriptors.
	*/
	if (!rx_stats->rs_more && rx_stats->rs_status != 0) {
	if (rx_stats->rs_status & ATH9K_RXERR_CRC)
	rxs->flag \|= RX_FLAG_FAILED_FCS_CRC;
	if (rx_stats->rs_status & ATH9K_RXERR_PHY)
	return false;

	if (rx_stats->rs_status & ATH9K_RXERR_DECRYPT) {
	*decrypt_error = true;
	} else if (rx_stats->rs_status & ATH9K_RXERR_MIC) {
	if (ieee80211_is_ctl(fc))
	/*
	* Sometimes, we get invalid
	* MIC failures on valid control frames.
	* Remove these mic errors.
	*/
	rx_stats->rs_status &= ~ATH9K_RXERR_MIC;
	else
	rxs->flag \|= RX_FLAG_MMIC_ERROR;
	}
	/*
	* Reject error frames with the exception of
	* decryption and MIC failures. For monitor mode,
	* we also ignore the CRC error.
	*/
	if (ah->opmode == NL80211_IFTYPE_MONITOR) {
	if (rx_stats->rs_status &
	~(ATH9K_RXERR_DECRYPT \| ATH9K_RXERR_MIC \|
	ATH9K_RXERR_CRC))
	return false;
	} else {
	if (rx_stats->rs_status &
	~(ATH9K_RXERR_DECRYPT \| ATH9K_RXERR_MIC)) {
	return false;
	}
	}
	}
	return true;
	}

	static u8 ath9k_process_rate(struct ath_common *common,
	struct ieee80211_hw *hw,
	struct ath_rx_status *rx_stats,
	struct ieee80211_rx_status *rxs,
	struct sk_buff *skb)
	{
	struct ieee80211_supported_band *sband;
	enum ieee80211_band band;
	unsigned int i = 0;

	band = hw->conf.channel->band;
	sband = hw->wiphy->bands[band];

	if (rx_stats->rs_rate & 0x80) {
	/* HT rate */
	rxs->flag \|= RX_FLAG_HT;
	if (rx_stats->rs_flags & ATH9K_RX_2040)
	rxs->flag \|= RX_FLAG_40MHZ;
	if (rx_stats->rs_flags & ATH9K_RX_GI)
	rxs->flag \|= RX_FLAG_SHORT_GI;
	return rx_stats->rs_rate & 0x7f;
	}

	for (i = 0; i < sband->n_bitrates; i++) {
	if (sband->bitrates[i].hw_value == rx_stats->rs_rate)
	return i;
	if (sband->bitrates[i].hw_value_short == rx_stats->rs_rate) {
	rxs->flag \|= RX_FLAG_SHORTPRE;
	return i;
	}
	}

	/* No valid hardware bitrate found -- we should not get here */
	ath_print(common, ATH_DBG_XMIT, "unsupported hw bitrate detected "
	"0x%02x using 1 Mbit\n", rx_stats->rs_rate);
	if ((common->debug_mask & ATH_DBG_XMIT))
	print_hex_dump_bytes("", DUMP_PREFIX_NONE, skb->data, skb->len);

	return 0;
	}

	static void ath9k_process_rssi(struct ath_common *common,
	struct ieee80211_hw *hw,
	struct sk_buff *skb,
	struct ath_rx_status *rx_stats)
	{
	struct ath_hw *ah = common->ah;
	struct ieee80211_sta *sta;
	struct ieee80211_hdr *hdr;
	struct ath_node *an;
	int last_rssi = ATH_RSSI_DUMMY_MARKER;
	__le16 fc;

	hdr = (struct ieee80211_hdr *)skb->data;
	fc = hdr->frame_control;

	rcu_read_lock();
	/*
	* XXX: use ieee80211_find_sta! This requires quite a bit of work
	* under the current ath9k virtual wiphy implementation as we have
	* no way of tying a vif to wiphy. Typically vifs are attached to
	* at least one sdata of a wiphy on mac80211 but with ath9k virtual
	* wiphy you'd have to iterate over every wiphy and each sdata.
	*/
	sta = ieee80211_find_sta_by_hw(hw, hdr->addr2);
	if (sta) {
	an = (struct ath_node *) sta->drv_priv;
	if (rx_stats->rs_rssi != ATH9K_RSSI_BAD &&
	!rx_stats->rs_moreaggr)
	ATH_RSSI_LPF(an->last_rssi, rx_stats->rs_rssi);
	last_rssi = an->last_rssi;
	}
	rcu_read_unlock();

	if (likely(last_rssi != ATH_RSSI_DUMMY_MARKER))
	rx_stats->rs_rssi = ATH_EP_RND(last_rssi,
	ATH_RSSI_EP_MULTIPLIER);
	if (rx_stats->rs_rssi < 0)
	rx_stats->rs_rssi = 0;

	/* Update Beacon RSSI, this is used by ANI. */
	if (ieee80211_is_beacon(fc))
	ah->stats.avgbrssi = rx_stats->rs_rssi;
	}

	/*
	* For Decrypt or Demic errors, we only mark packet status here and always push
	* up the frame up to let mac80211 handle the actual error case, be it no
	* decryption key or real decryption error. This let us keep statistics there.
	*/
	int ath9k_cmn_rx_skb_preprocess(struct ath_common *common,
	struct ieee80211_hw *hw,
	struct sk_buff *skb,
	struct ath_rx_status *rx_stats,
	struct ieee80211_rx_status *rx_status,
	bool *decrypt_error)
	{
	struct ath_hw *ah = common->ah;

	memset(rx_status, 0, sizeof(struct ieee80211_rx_status));
	if (!ath9k_rx_accept(common, skb, rx_status, rx_stats, decrypt_error))
	return -EINVAL;

	ath9k_process_rssi(common, hw, skb, rx_stats);

	rx_status->rate_idx = ath9k_process_rate(common, hw,
	rx_stats, rx_status, skb);
	rx_status->mactime = ath9k_hw_extend_tsf(ah, rx_stats->rs_tstamp);
	rx_status->band = hw->conf.channel->band;
	rx_status->freq = hw->conf.channel->center_freq;
	rx_status->noise = common->ani.noise_floor;
	rx_status->signal = ATH_DEFAULT_NOISE_FLOOR + rx_stats->rs_rssi;
	rx_status->antenna = rx_stats->rs_antenna;
	rx_status->flag \|= RX_FLAG_TSFT;

	return 0;
	}
	EXPORT_SYMBOL(ath9k_cmn_rx_skb_preprocess);

	void ath9k_cmn_rx_skb_postprocess(struct ath_common *common,
	struct sk_buff *skb,
	struct ath_rx_status *rx_stats,
	struct ieee80211_rx_status *rxs,
	bool decrypt_error)
	{
	struct ath_hw *ah = common->ah;
	struct ieee80211_hdr *hdr;
	int hdrlen, padpos, padsize;
	u8 keyix;
	__le16 fc;

	/* see if any padding is done by the hw and remove it */
	hdr = (struct ieee80211_hdr *) skb->data;
	hdrlen = ieee80211_get_hdrlen_from_skb(skb);
	fc = hdr->frame_control;
	padpos = ath9k_cmn_padpos(hdr->frame_control);

	/* The MAC header is padded to have 32-bit boundary if the
	* packet payload is non-zero. The general calculation for
	* padsize would take into account odd header lengths:
	* padsize = (4 - padpos % 4) % 4; However, since only
	* even-length headers are used, padding can only be 0 or 2
	* bytes and we can optimize this a bit. In addition, we must
	* not try to remove padding from short control frames that do
	* not have payload. */
	padsize = padpos & 3;
	if (padsize && skb->len>=padpos+padsize+FCS_LEN) {
	memmove(skb->data + padsize, skb->data, padpos);
	skb_pull(skb, padsize);
	}

	keyix = rx_stats->rs_keyix;

	if (!(keyix == ATH9K_RXKEYIX_INVALID) && !decrypt_error) {
	rxs->flag \|= RX_FLAG_DECRYPTED;
	} else if (ieee80211_has_protected(fc)
	&& !decrypt_error && skb->len >= hdrlen + 4) {
	keyix = skb->data[hdrlen + 3] >> 6;

	if (test_bit(keyix, common->keymap))
	rxs->flag \|= RX_FLAG_DECRYPTED;
	}
	if (ah->sw_mgmt_crypto &&
	(rxs->flag & RX_FLAG_DECRYPTED) &&
	ieee80211_is_mgmt(fc))
	/* Use software decrypt for management frames. */
	rxs->flag &= ~RX_FLAG_DECRYPTED;
	}
	EXPORT_SYMBOL(ath9k_cmn_rx_skb_postprocess);

	int ath9k_cmn_padpos(__le16 frame_control)
	{
	int padpos = 24;
	if (ieee80211_has_a4(frame_control)) {
	padpos += ETH_ALEN;
	}
	if (ieee80211_is_data_qos(frame_control)) {
	padpos += IEEE80211_QOS_CTL_LEN;
	}

	return padpos;
	}
	EXPORT_SYMBOL(ath9k_cmn_padpos);

	static int __init ath9k_cmn_init(void)
	{
	return 0;
	}
	module_init(ath9k_cmn_init);

	static void __exit ath9k_cmn_exit(void)
	{
	return;
	}
	module_exit(ath9k_cmn_exit);