path: root/drivers/net/wireless/ath/ath9k/calib.c

/*
 * Copyright (c) 2008-2009 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.
 */

#include "ath9k.h"

/* We can tune this as we go by monitoring really low values */
#define ATH9K_NF_TOO_LOW	-60

/* AR5416 may return very high value (like -31 dBm), in those cases the nf
 * is incorrect and we should use the static NF value. Later we can try to
 * find out why they are reporting these values */

static bool ath9k_hw_nf_in_range(struct ath_hw *ah, s16 nf)
{
	if (nf > ATH9K_NF_TOO_LOW) {
		DPRINTF(ah->ah_sc, ATH_DBG_CALIBRATE,
			"noise floor value detected (%d) is "
			"lower than what we think is a "
			"reasonable value (%d)\n",
			nf, ATH9K_NF_TOO_LOW);
		return false;
	}
	return true;
}

static int16_t ath9k_hw_get_nf_hist_mid(int16_t *nfCalBuffer)
{
	int16_t nfval;
	int16_t sort[ATH9K_NF_CAL_HIST_MAX];
	int i, j;

	for (i = 0; i < ATH9K_NF_CAL_HIST_MAX; i++)
		sort[i] = nfCalBuffer[i];

	for (i = 0; i < ATH9K_NF_CAL_HIST_MAX - 1; i++) {
		for (j = 1; j < ATH9K_NF_CAL_HIST_MAX - i; j++) {
			if (sort[j] > sort[j - 1]) {
				nfval = sort[j];
				sort[j] = sort[j - 1];
				sort[j - 1] = nfval;
			}
		}
	}
	nfval = sort[(ATH9K_NF_CAL_HIST_MAX - 1) >> 1];

	return nfval;
}

static void ath9k_hw_update_nfcal_hist_buffer(struct ath9k_nfcal_hist *h,
					      int16_t *nfarray)
{
	int i;

	for (i = 0; i < NUM_NF_READINGS; i++) {
		h[i].nfCalBuffer[h[i].currIndex] = nfarray[i];

		if (++h[i].currIndex >= ATH9K_NF_CAL_HIST_MAX)
			h[i].currIndex = 0;

		if (h[i].invalidNFcount > 0) {
			if (nfarray[i] < AR_PHY_CCA_MIN_BAD_VALUE ||
			    nfarray[i] > AR_PHY_CCA_MAX_HIGH_VALUE) {
				h[i].invalidNFcount = ATH9K_NF_CAL_HIST_MAX;
			} else {
				h[i].invalidNFcount--;
				h[i].privNF = nfarray[i];
			}
		} else {
			h[i].privNF =
				ath9k_hw_get_nf_hist_mid(h[i].nfCalBuffer);
		}
	}
	return;
}

static void ath9k_hw_do_getnf(struct ath_hw *ah,
			      int16_t nfarray[NUM_NF_READINGS])
{
	int16_t nf;

	if (AR_SREV_9280_10_OR_LATER(ah))
		nf = MS(REG_READ(ah, AR_PHY_CCA), AR9280_PHY_MINCCA_PWR);
	else
		nf = MS(REG_READ(ah, AR_PHY_CCA), AR_PHY_MINCCA_PWR);

	if (nf & 0x100)
		nf = 0 - ((nf ^ 0x1ff) + 1);
	DPRINTF(ah->ah_sc, ATH_DBG_CALIBRATE,
		"NF calibrated [ctl] [chain 0] is %d\n", nf);
	nfarray[0] = nf;

	if (!AR_SREV_9285(ah)) {
		if (AR_SREV_9280_10_OR_LATER(ah))
			nf = MS(REG_READ(ah, AR_PHY_CH1_CCA),
					AR9280_PHY_CH1_MINCCA_PWR);
		else
			nf = MS(REG_READ(ah, AR_PHY_CH1_CCA),
					AR_PHY_CH1_MINCCA_PWR);

		if (nf & 0x100)
			nf = 0 - ((nf ^ 0x1ff) + 1);
		DPRINTF(ah->ah_sc, ATH_DBG_CALIBRATE,
				"NF calibrated [ctl] [chain 1] is %d\n", nf);
		nfarray[1] = nf;

		if (!AR_SREV_9280(ah)) {
			nf = MS(REG_READ(