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);