diff options
Diffstat (limited to 'drivers/net/wireless/ath/ath9k/common.c')
| -rw-r--r-- | drivers/net/wireless/ath/ath9k/common.c | 326 |
1 files changed, 326 insertions, 0 deletions
diff --git a/drivers/net/wireless/ath/ath9k/common.c b/drivers/net/wireless/ath/ath9k/common.c new file mode 100644 index 000000000000..5fb164e294de --- /dev/null +++ b/drivers/net/wireless/ath/ath9k/common.c @@ -0,0 +1,326 @@ +/* + * 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; + + if (rx_stats->rs_more) { + /* + * Frame spans multiple descriptors; this cannot happen yet + * as we don't support jumbograms. If not in monitor mode, + * discard the frame. Enable this if you want to see + * error frames in Monitor mode. + */ + if (ah->opmode != NL80211_IFTYPE_MONITOR) + return false; + } else if (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; +} + +/* + * Theory for reporting quality: + * + * At a hardware RSSI of 45 you will be able to use MCS 7 reliably. + * At a hardware RSSI of 45 you will be able to use MCS 15 reliably. + * At a hardware RSSI of 35 you should be able use 54 Mbps reliably. + * + * MCS 7 is the highets MCS index usable by a 1-stream device. + * MCS 15 is the highest MCS index usable by a 2-stream device. + * + * All ath9k devices are either 1-stream or 2-stream. + * + * How many bars you see is derived from the qual reporting. + * + * A more elaborate scheme can be used here but it requires tables + * of SNR/throughput for each possible mode used. For the MCS table + * you can refer to the wireless wiki: + * + * http://wireless.kernel.org/en/developers/Documentation/ieee80211/802.11n + * + */ +static int ath9k_compute_qual(struct ieee80211_hw *hw, + struct ath_rx_status *rx_stats) +{ + int qual; + + if (conf_is_ht(&hw->conf)) + qual = rx_stats->rs_rssi * 100 / 45; + else + qual = rx_stats->rs_rssi * 100 / 35; + + /* + * rssi can be more than 45 though, anything above that + * should be considered at 100% + */ + if (qual > 100) + qual = 100; + + return qual; +} + +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; + else if (rx_stats->rs_rssi > 127) + rx_stats->rs_rssi = 127; + + /* 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; + + 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->qual = ath9k_compute_qual(hw, rx_stats); + 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, 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; + + /* 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 - hdrlen % 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 = hdrlen & 3; + if (padsize && hdrlen >= 24) { + memmove(skb->data + padsize, skb->data, hdrlen); + 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); + +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); |