/*
* 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);
