core/sap/dfs/src/dfs_misc.c

/*
 * Copyright (c) 2002-2014 The Linux Foundation. All rights reserved.
 *
 * Previously licensed under the ISC license by Qualcomm Atheros, 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.
 */

/*
 * This file was originally distributed by Qualcomm Atheros, Inc.
 * under proprietary terms before Copyright ownership was assigned
 * to the Linux Foundation.
 */

/*===========================================================================

                     dfs_misc.c

   OVERVIEW:

   Source code borrowed from QCA_MAIN DFS module

   DEPENDENCIES:

   Are listed for each API below.

   ===========================================================================*/

/*===========================================================================

                      EDIT HISTORY FOR FILE

   This section contains comments describing changes made to the module.
   Notice that changes are listed in reverse chronological order.

   when        who     what, where, why
   ----------    ---    --------------------------------------------------------

   ===========================================================================*/

#include "dfs.h"
/* TO DO DFS
   #include <ieee80211_var.h>
 */
#ifndef UNINET
/* TO DO DFS
   #include <ieee80211_channel.h>
 */
#endif
#ifdef ATH_SUPPORT_DFS

static int adjust_pri_per_chan_busy(int ext_chan_busy, int pri_margin)
{
	int adjust_pri = 0;

	if (ext_chan_busy > DFS_EXT_CHAN_LOADING_THRESH) {

		adjust_pri =
			(ext_chan_busy -
			 DFS_EXT_CHAN_LOADING_THRESH) * (pri_margin);
		adjust_pri /= 100;

	}
	return adjust_pri;
}

static int adjust_thresh_per_chan_busy(int ext_chan_busy, int thresh)
{
	int adjust_thresh = 0;

	if (ext_chan_busy > DFS_EXT_CHAN_LOADING_THRESH) {

		adjust_thresh =
			(ext_chan_busy - DFS_EXT_CHAN_LOADING_THRESH) * thresh;
		adjust_thresh /= 100;

	}
	return adjust_thresh;
}

/* For the extension channel, if legacy traffic is present, we see a lot of false alarms,
   so make the PRI margin narrower depending on the busy % for the extension channel.*/

int
dfs_get_pri_margin(struct ath_dfs *dfs, int is_extchan_detect,
		   int is_fixed_pattern)
{

	int adjust_pri = 0, ext_chan_busy = 0;
	int pri_margin;

	if (is_fixed_pattern)
		pri_margin = DFS_DEFAULT_FIXEDPATTERN_PRI_MARGIN;
	else
		pri_margin = DFS_DEFAULT_PRI_MARGIN;

	if (IS_CHAN_HT40(dfs->ic->ic_curchan)) {
		ext_chan_busy = dfs->ic->ic_get_ext_busy(dfs->ic);
		if (ext_chan_busy >= 0) {
			dfs->dfs_rinfo.ext_chan_busy_ts =
				dfs->ic->ic_get_TSF64(dfs->ic);
			dfs->dfs_rinfo.dfs_ext_chan_busy = ext_chan_busy;
		} else {
			/* Check to see if the cached value of ext_chan_busy can be used */
			ext_chan_busy = 0;
			if (dfs->dfs_rinfo.dfs_ext_chan_busy) {
				if (dfs->dfs_rinfo.rn_lastfull_ts <
				    dfs->dfs_rinfo.ext_chan_busy_ts) {
					ext_chan_busy =
						dfs->dfs_rinfo.dfs_ext_chan_busy;
					DFS_DPRINTK(dfs, ATH_DEBUG_DFS2,
						    " PRI Use cached copy of ext_chan_busy extchanbusy=%d \n",
						    ext_chan_busy);
				}
			}
		}
		adjust_pri =
			adjust_pri_per_chan_busy(ext_chan_busy, pri_margin);

		pri_margin -= adjust_pri;
	}
	return pri_margin;
}

/* For the extension channel, if legacy traffic is present, we see a lot of false alarms,
   so make the thresholds higher depending on the busy % for the extension channel.*/

int dfs_get_filter_threshold(struct ath_dfs *dfs, struct dfs_filter *rf,
			     int is_extchan_detect)
{
	int ext_chan_busy = 0;
	int thresh, adjust_thresh = 0;

	thresh = rf->rf_threshold;

	if (IS_CHAN_HT40(dfs->ic->ic_curchan)) {
		ext_chan_busy = dfs->ic->ic_get_ext_busy(dfs->ic);
		if (ext_chan_busy >= 0) {
			dfs->dfs_rinfo.ext_chan_busy_ts =
				dfs->ic->ic_get_TSF64(dfs->ic);
			dfs->dfs_rinfo.dfs_ext_chan_busy = ext_chan_busy;
		} else {
			/* Check to see if the cached value of ext_chan_busy can be used */
			ext_chan_busy = 0;
			if (dfs->dfs_rinfo.dfs_ext_chan_busy) {
				if (dfs->dfs_rinfo.rn_lastfull_ts <
				    dfs->dfs_rinfo.ext_chan_busy_ts) {
					ext_chan_busy =
						dfs->dfs_rinfo.dfs_ext_chan_busy;
					DFS_DPRINTK(dfs, ATH_DEBUG_DFS2,
						    " THRESH Use cached copy of ext_chan_busy extchanbusy=%d rn_lastfull_ts=%llu ext_chan_busy_ts=%llu\n",
						    ext_chan_busy,
						    (unsigned long long)dfs->
						    dfs_rinfo.rn_lastfull_ts,
						    (unsigned long long)dfs->
						    dfs_rinfo.ext_chan_busy_ts);
				}
			}
		}

		adjust_thresh =
			adjust_thresh_per_chan_busy(ext_chan_busy, thresh);

		DFS_DPRINTK(dfs, ATH_DEBUG_DFS2,
			    " filterID=%d extchanbusy=%d adjust_thresh=%d\n",
			    rf->rf_pulseid, ext_chan_busy, adjust_thresh);

		thresh += adjust_thresh;
	}
	return thresh;
}

uint32_t dfs_round(int32_t val)
{
	uint32_t ival, rem;

	if (val < 0)
		return 0;
	ival = val / 100;
	rem = val - (ival * 100);
	if (rem < 50)
		return ival;
	else
		return (ival + 1);
}

struct ieee80211_channel *ieee80211_get_extchan(struct ieee80211com *ic)
{
	int chan_offset = 0;
	if (IEEE80211_IS_CHAN_HT40PLUS_CAPABLE(ic->ic_curchan)) {
		chan_offset = 20;
	} else if (IEEE80211_IS_CHAN_HT40MINUS_CAPABLE(ic->ic_curchan)) {
		chan_offset = -20;
	} else {
		return NULL;
	}
	return (ic->
		ic_find_channel(ic, ic->ic_curchan->ic_freq + chan_offset,
				IEEE80211_CHAN_11NA_HT20));
}

/*
 * Finds the radar state entry that matches the current channel
 */
struct dfs_state *dfs_getchanstate(struct ath_dfs *dfs, uint8_t *index,
				   int ext_chan_flag)
{
	struct dfs_state *rs = NULL;
	int i;
	struct ieee80211_channel *cmp_ch;

	if (dfs == NULL) {
		printk("%s[%d]: sc_dfs is NULL\n", __func__, __LINE__);
		/* DFS_DPRINTK(dfs, ATH_DEBUG_DFS,"%s: sc_dfs is NULL\n",__func__); */
		return NULL;
	}

	if (ext_chan_flag) {
		cmp_ch = ieee80211_get_extchan(dfs->ic);
		if (cmp_ch) {
			DFS_DPRINTK(dfs, ATH_DEBUG_DFS2,
				    "Extension channel freq = %u flags=0x%x\n",
				    cmp_ch->ic_freq, cmp_ch->ic_flagext);
		} else {
			return NULL;
		}

	} else {
		cmp_ch = dfs->ic->ic_curchan;
		DFS_DPRINTK(dfs, ATH_DEBUG_DFS2,
			    "Primary channel freq = %u flags=0x%x\n",
			    cmp_ch->ic_freq, cmp_ch->ic_flagext);
	}
	for (i = 0; i < DFS_NUM_RADAR_STATES; i++) {
		if ((dfs->dfs_radar[i].rs_chan.ic_freq == cmp_ch->ic_freq) &&
		    (dfs->dfs_radar[i].rs_chan.ic_flags == cmp_ch->ic_flags)) {
			if (index != NULL)
				*index = (uint8_t) i;
			return &(dfs->dfs_radar[i]);
		}
	}
	/* No existing channel found, look for first free channel state entry */
	for (i = 0; i < DFS_NUM_RADAR_STATES; i++) {
		if (dfs->dfs_radar[i].rs_chan.ic_freq == 0) {
			rs = &(dfs->dfs_radar[i]);
			/* Found one, set channel info and default thresholds */
			rs->rs_chan = *cmp_ch;

			/* Copy the parameters from the default set */
			ath_dfs_phyerr_param_copy(&rs->rs_param,
						  &dfs->dfs_defaultparams);

			if (index != NULL)
				*index = (uint8_t) i;
			return (rs);
		}
	}
	DFS_DPRINTK(dfs, ATH_DEBUG_DFS2, "%s: No more radar states left.\n",
		    __func__);
	return (NULL);
}

#endif /* ATH_SUPPORT_DFS */