363 lines
10 KiB
C
363 lines
10 KiB
C
/*
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* Copyright (c) 2008-2011 Atheros Communications Inc.
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* Copyright (c) 2011 Neratec Solutions AG
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "hw.h"
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#include "hw-ops.h"
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#include "ath9k.h"
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#include "dfs.h"
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#include "dfs_debug.h"
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/* internal struct to pass radar data */
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struct ath_radar_data {
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u8 pulse_bw_info;
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u8 rssi;
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u8 ext_rssi;
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u8 pulse_length_ext;
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u8 pulse_length_pri;
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};
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/**** begin: CHIRP ************************************************************/
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/* min and max gradients for defined FCC chirping pulses, given by
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* - 20MHz chirp width over a pulse width of 50us
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* - 5MHz chirp width over a pulse width of 100us
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*/
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static const int BIN_DELTA_MIN = 1;
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static const int BIN_DELTA_MAX = 10;
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/* we need at least 3 deltas / 4 samples for a reliable chirp detection */
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#define NUM_DIFFS 3
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static const int FFT_NUM_SAMPLES = (NUM_DIFFS + 1);
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/* Threshold for difference of delta peaks */
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static const int MAX_DIFF = 2;
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/* width range to be checked for chirping */
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static const int MIN_CHIRP_PULSE_WIDTH = 20;
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static const int MAX_CHIRP_PULSE_WIDTH = 110;
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struct ath9k_dfs_fft_20 {
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u8 bin[28];
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u8 lower_bins[3];
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} __packed;
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struct ath9k_dfs_fft_40 {
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u8 bin[64];
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u8 lower_bins[3];
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u8 upper_bins[3];
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} __packed;
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static inline int fft_max_index(u8 *bins)
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{
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return (bins[2] & 0xfc) >> 2;
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}
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static inline int fft_max_magnitude(u8 *bins)
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{
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return (bins[0] & 0xc0) >> 6 | bins[1] << 2 | (bins[2] & 0x03) << 10;
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}
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static inline u8 fft_bitmap_weight(u8 *bins)
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{
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return bins[0] & 0x3f;
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}
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static int ath9k_get_max_index_ht40(struct ath9k_dfs_fft_40 *fft,
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bool is_ctl, bool is_ext)
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{
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const int DFS_UPPER_BIN_OFFSET = 64;
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/* if detected radar on both channels, select the significant one */
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if (is_ctl && is_ext) {
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/* first check wether channels have 'strong' bins */
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is_ctl = fft_bitmap_weight(fft->lower_bins) != 0;
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is_ext = fft_bitmap_weight(fft->upper_bins) != 0;
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/* if still unclear, take higher magnitude */
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if (is_ctl && is_ext) {
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int mag_lower = fft_max_magnitude(fft->lower_bins);
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int mag_upper = fft_max_magnitude(fft->upper_bins);
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if (mag_upper > mag_lower)
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is_ctl = false;
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else
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is_ext = false;
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}
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}
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if (is_ctl)
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return fft_max_index(fft->lower_bins);
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return fft_max_index(fft->upper_bins) + DFS_UPPER_BIN_OFFSET;
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}
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static bool ath9k_check_chirping(struct ath_softc *sc, u8 *data,
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int datalen, bool is_ctl, bool is_ext)
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{
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int i;
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int max_bin[FFT_NUM_SAMPLES];
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struct ath_hw *ah = sc->sc_ah;
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struct ath_common *common = ath9k_hw_common(ah);
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int prev_delta;
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if (IS_CHAN_HT40(ah->curchan)) {
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struct ath9k_dfs_fft_40 *fft = (struct ath9k_dfs_fft_40 *) data;
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int num_fft_packets = datalen / sizeof(*fft);
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if (num_fft_packets == 0)
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return false;
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ath_dbg(common, DFS, "HT40: datalen=%d, num_fft_packets=%d\n",
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datalen, num_fft_packets);
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if (num_fft_packets < (FFT_NUM_SAMPLES)) {
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ath_dbg(common, DFS, "not enough packets for chirp\n");
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return false;
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}
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/* HW sometimes adds 2 garbage bytes in front of FFT samples */
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if ((datalen % sizeof(*fft)) == 2) {
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fft = (struct ath9k_dfs_fft_40 *) (data + 2);
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ath_dbg(common, DFS, "fixing datalen by 2\n");
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}
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if (IS_CHAN_HT40MINUS(ah->curchan)) {
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int temp = is_ctl;
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is_ctl = is_ext;
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is_ext = temp;
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}
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for (i = 0; i < FFT_NUM_SAMPLES; i++)
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max_bin[i] = ath9k_get_max_index_ht40(fft + i, is_ctl,
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is_ext);
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} else {
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struct ath9k_dfs_fft_20 *fft = (struct ath9k_dfs_fft_20 *) data;
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int num_fft_packets = datalen / sizeof(*fft);
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if (num_fft_packets == 0)
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return false;
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ath_dbg(common, DFS, "HT20: datalen=%d, num_fft_packets=%d\n",
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datalen, num_fft_packets);
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if (num_fft_packets < (FFT_NUM_SAMPLES)) {
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ath_dbg(common, DFS, "not enough packets for chirp\n");
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return false;
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}
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/* in ht20, this is a 6-bit signed number => shift it to 0 */
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for (i = 0; i < FFT_NUM_SAMPLES; i++)
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max_bin[i] = fft_max_index(fft[i].lower_bins) ^ 0x20;
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}
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ath_dbg(common, DFS, "bin_max = [%d, %d, %d, %d]\n",
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max_bin[0], max_bin[1], max_bin[2], max_bin[3]);
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/* Check for chirp attributes within specs
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* a) delta of adjacent max_bins is within range
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* b) delta of adjacent deltas are within tolerance
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*/
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prev_delta = 0;
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for (i = 0; i < NUM_DIFFS; i++) {
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int ddelta = -1;
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int delta = max_bin[i + 1] - max_bin[i];
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/* ensure gradient is within valid range */
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if (abs(delta) < BIN_DELTA_MIN || abs(delta) > BIN_DELTA_MAX) {
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ath_dbg(common, DFS, "CHIRP: invalid delta %d "
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"in sample %d\n", delta, i);
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return false;
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}
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if (i == 0)
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goto done;
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ddelta = delta - prev_delta;
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if (abs(ddelta) > MAX_DIFF) {
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ath_dbg(common, DFS, "CHIRP: ddelta %d too high\n",
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ddelta);
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return false;
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}
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done:
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ath_dbg(common, DFS, "CHIRP - %d: delta=%d, ddelta=%d\n",
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i, delta, ddelta);
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prev_delta = delta;
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}
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return true;
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}
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/**** end: CHIRP **************************************************************/
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/* convert pulse duration to usecs, considering clock mode */
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static u32 dur_to_usecs(struct ath_hw *ah, u32 dur)
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{
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const u32 AR93X_NSECS_PER_DUR = 800;
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const u32 AR93X_NSECS_PER_DUR_FAST = (8000 / 11);
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u32 nsecs;
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if (IS_CHAN_A_FAST_CLOCK(ah, ah->curchan))
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nsecs = dur * AR93X_NSECS_PER_DUR_FAST;
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else
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nsecs = dur * AR93X_NSECS_PER_DUR;
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return (nsecs + 500) / 1000;
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}
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#define PRI_CH_RADAR_FOUND 0x01
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#define EXT_CH_RADAR_FOUND 0x02
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static bool
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ath9k_postprocess_radar_event(struct ath_softc *sc,
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struct ath_radar_data *ard,
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struct pulse_event *pe)
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{
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u8 rssi;
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u16 dur;
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/*
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* Only the last 2 bits of the BW info are relevant, they indicate
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* which channel the radar was detected in.
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*/
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ard->pulse_bw_info &= 0x03;
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switch (ard->pulse_bw_info) {
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case PRI_CH_RADAR_FOUND:
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/* radar in ctrl channel */
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dur = ard->pulse_length_pri;
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DFS_STAT_INC(sc, pri_phy_errors);
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/*
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* cannot use ctrl channel RSSI
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* if extension channel is stronger
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*/
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rssi = (ard->ext_rssi >= (ard->rssi + 3)) ? 0 : ard->rssi;
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break;
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case EXT_CH_RADAR_FOUND:
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/* radar in extension channel */
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dur = ard->pulse_length_ext;
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DFS_STAT_INC(sc, ext_phy_errors);
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/*
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* cannot use extension channel RSSI
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* if control channel is stronger
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*/
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rssi = (ard->rssi >= (ard->ext_rssi + 12)) ? 0 : ard->ext_rssi;
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break;
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case (PRI_CH_RADAR_FOUND | EXT_CH_RADAR_FOUND):
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/*
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* Conducted testing, when pulse is on DC, both pri and ext
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* durations are reported to be same
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*
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* Radiated testing, when pulse is on DC, different pri and
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* ext durations are reported, so take the larger of the two
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*/
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if (ard->pulse_length_ext >= ard->pulse_length_pri)
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dur = ard->pulse_length_ext;
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else
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dur = ard->pulse_length_pri;
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DFS_STAT_INC(sc, dc_phy_errors);
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/* when both are present use stronger one */
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rssi = (ard->rssi < ard->ext_rssi) ? ard->ext_rssi : ard->rssi;
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break;
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default:
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/*
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* Bogus bandwidth info was received in descriptor,
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* so ignore this PHY error
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*/
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DFS_STAT_INC(sc, bwinfo_discards);
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return false;
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}
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if (rssi == 0) {
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DFS_STAT_INC(sc, rssi_discards);
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return false;
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}
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/* convert duration to usecs */
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pe->width = dur_to_usecs(sc->sc_ah, dur);
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pe->rssi = rssi;
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DFS_STAT_INC(sc, pulses_detected);
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return true;
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}
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static void
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ath9k_dfs_process_radar_pulse(struct ath_softc *sc, struct pulse_event *pe)
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{
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struct dfs_pattern_detector *pd = sc->dfs_detector;
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DFS_STAT_INC(sc, pulses_processed);
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if (pd == NULL)
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return;
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if (!pd->add_pulse(pd, pe))
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return;
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DFS_STAT_INC(sc, radar_detected);
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ieee80211_radar_detected(sc->hw);
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}
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/*
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* DFS: check PHY-error for radar pulse and feed the detector
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*/
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void ath9k_dfs_process_phyerr(struct ath_softc *sc, void *data,
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struct ath_rx_status *rs, u64 mactime)
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{
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struct ath_radar_data ard;
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u16 datalen;
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char *vdata_end;
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struct pulse_event pe;
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struct ath_hw *ah = sc->sc_ah;
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struct ath_common *common = ath9k_hw_common(ah);
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DFS_STAT_INC(sc, pulses_total);
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if ((rs->rs_phyerr != ATH9K_PHYERR_RADAR) &&
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(rs->rs_phyerr != ATH9K_PHYERR_FALSE_RADAR_EXT)) {
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ath_dbg(common, DFS,
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"Error: rs_phyer=0x%x not a radar error\n",
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rs->rs_phyerr);
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DFS_STAT_INC(sc, pulses_no_dfs);
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return;
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}
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datalen = rs->rs_datalen;
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if (datalen == 0) {
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DFS_STAT_INC(sc, datalen_discards);
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return;
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}
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ard.rssi = rs->rs_rssi_ctl[0];
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ard.ext_rssi = rs->rs_rssi_ext[0];
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/*
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* hardware stores this as 8 bit signed value.
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* we will cap it at 0 if it is a negative number
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*/
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if (ard.rssi & 0x80)
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ard.rssi = 0;
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if (ard.ext_rssi & 0x80)
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ard.ext_rssi = 0;
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vdata_end = (char *)data + datalen;
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ard.pulse_bw_info = vdata_end[-1];
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ard.pulse_length_ext = vdata_end[-2];
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ard.pulse_length_pri = vdata_end[-3];
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pe.freq = ah->curchan->channel;
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pe.ts = mactime;
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if (!ath9k_postprocess_radar_event(sc, &ard, &pe))
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return;
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if (pe.width > MIN_CHIRP_PULSE_WIDTH &&
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pe.width < MAX_CHIRP_PULSE_WIDTH) {
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bool is_ctl = !!(ard.pulse_bw_info & PRI_CH_RADAR_FOUND);
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bool is_ext = !!(ard.pulse_bw_info & EXT_CH_RADAR_FOUND);
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int clen = datalen - 3;
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pe.chirp = ath9k_check_chirping(sc, data, clen, is_ctl, is_ext);
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} else {
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pe.chirp = false;
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}
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ath_dbg(common, DFS,
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"ath9k_dfs_process_phyerr: type=%d, freq=%d, ts=%llu, "
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"width=%d, rssi=%d, delta_ts=%llu\n",
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ard.pulse_bw_info, pe.freq, pe.ts, pe.width, pe.rssi,
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pe.ts - sc->dfs_prev_pulse_ts);
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sc->dfs_prev_pulse_ts = pe.ts;
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if (ard.pulse_bw_info & PRI_CH_RADAR_FOUND)
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ath9k_dfs_process_radar_pulse(sc, &pe);
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if (IS_CHAN_HT40(ah->curchan) &&
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ard.pulse_bw_info & EXT_CH_RADAR_FOUND) {
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pe.freq += IS_CHAN_HT40PLUS(ah->curchan) ? 20 : -20;
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ath9k_dfs_process_radar_pulse(sc, &pe);
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}
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}
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#undef PRI_CH_RADAR_FOUND
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#undef EXT_CH_RADAR_FOUND
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