2009/10/14 Bob Copeland <me@xxxxxxxxxxxxxxx>:
> This updates ath5k to calibrate the noise floor similar to the
> way it is done in the madwifi hal and ath9k. Of note:
>
> - we start NF measurement at the same time as AGC calibration,
> but do not actually read the value until the periodic (long)
> calibration
> - we keep a history of the last few values read and write the
> median back to the hardware for CCA
> - we do not complain if NF calibration isn't complete, instead
> we keep the last read value.
>
> Signed-off-by: Bob Copeland <me@xxxxxxxxxxxxxxx>
> ---
> drivers/net/wireless/ath/ath5k/ath5k.h | 13 ++
> drivers/net/wireless/ath/ath5k/attach.c | 2 +
> drivers/net/wireless/ath/ath5k/phy.c | 185 +++++++++++++++++++++----------
> drivers/net/wireless/ath/ath5k/reg.h | 11 +-
> drivers/net/wireless/ath/ath5k/reset.c | 17 +---
> 5 files changed, 148 insertions(+), 80 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath5k/ath5k.h b/drivers/net/wireless/ath/ath5k/ath5k.h
> index 6cd5efc..1c90d6b 100644
> --- a/drivers/net/wireless/ath/ath5k/ath5k.h
> +++ b/drivers/net/wireless/ath/ath5k/ath5k.h
> @@ -204,6 +204,7 @@
> #define AR5K_TUNE_CWMAX_11B 1023
> #define AR5K_TUNE_CWMAX_XR 7
> #define AR5K_TUNE_NOISE_FLOOR -72
> +#define AR5K_TUNE_CCA_MAX_GOOD_VALUE -95
> #define AR5K_TUNE_MAX_TXPOWER 63
> #define AR5K_TUNE_DEFAULT_TXPOWER 25
> #define AR5K_TUNE_TPC_TXPOWER false
> @@ -1012,6 +1013,14 @@ struct ath5k_capabilities {
> } cap_queues;
> };
>
> +/* size of noise floor history (keep it a power of two) */
> +#define ATH5K_NF_CAL_HIST_MAX 8
> +struct ath5k_nfcal_hist
> +{
> + s16 index; /* current index into nfval */
> + s16 nfval[ATH5K_NF_CAL_HIST_MAX]; /* last few noise floors */
> +};
> +
>
> /***************************************\
> HARDWARE ABSTRACTION LAYER STRUCTURE
> @@ -1125,6 +1134,8 @@ struct ath5k_hw {
> struct ieee80211_channel r_last_channel;
> } ah_radar;
>
> + struct ath5k_nfcal_hist ah_nfcal_hist;
> +
> /* noise floor from last periodic calibration */
> s32 ah_noise_floor;
>
> @@ -1288,8 +1299,10 @@ extern int ath5k_hw_rfgain_opt_init(struct ath5k_hw *ah);
> extern bool ath5k_channel_ok(struct ath5k_hw *ah, u16 freq, unsigned int flags);
> extern int ath5k_hw_channel(struct ath5k_hw *ah, struct ieee80211_channel *channel);
> /* PHY calibration */
> +void ath5k_hw_init_nfcal_hist(struct ath5k_hw *ah);
> extern int ath5k_hw_phy_calibrate(struct ath5k_hw *ah, struct ieee80211_channel *channel);
> extern int ath5k_hw_noise_floor_calibration(struct ath5k_hw *ah, short freq);
> +extern s16 ath5k_hw_get_noise_floor(struct ath5k_hw *ah);
> extern void ath5k_hw_calibration_poll(struct ath5k_hw *ah);
> /* Spur mitigation */
> bool ath5k_hw_chan_has_spur_noise(struct ath5k_hw *ah,
> diff --git a/drivers/net/wireless/ath/ath5k/attach.c b/drivers/net/wireless/ath/ath5k/attach.c
> index 71a1bd2..1ec85af 100644
> --- a/drivers/net/wireless/ath/ath5k/attach.c
> +++ b/drivers/net/wireless/ath/ath5k/attach.c
> @@ -342,6 +342,8 @@ struct ath5k_hw *ath5k_hw_attach(struct ath5k_softc *sc)
>
> ath5k_hw_rfgain_opt_init(ah);
>
> + ath5k_hw_init_nfcal_hist(ah);
> +
> /* turn on HW LEDs */
> ath5k_hw_set_ledstate(ah, AR5K_LED_INIT);
>
> diff --git a/drivers/net/wireless/ath/ath5k/phy.c b/drivers/net/wireless/ath/ath5k/phy.c
> index 1a039f2..8959907 100644
> --- a/drivers/net/wireless/ath/ath5k/phy.c
> +++ b/drivers/net/wireless/ath/ath5k/phy.c
> @@ -1124,77 +1124,148 @@ ath5k_hw_calibration_poll(struct ath5k_hw *ah)
> ah->ah_swi_mask = AR5K_SWI_FULL_CALIBRATION;
> AR5K_REG_ENABLE_BITS(ah, AR5K_CR, AR5K_CR_SWI);
> }
> +}
>
> +static int sign_extend(int val, const int nbits)
> +{
> + int order = BIT(nbits-1);
> + return (val ^ order) - order;
> }
>
> -/**
> - * ath5k_hw_noise_floor_calibration - perform PHY noise floor calibration
> - *
> - * @ah: struct ath5k_hw pointer we are operating on
> - * @freq: the channel frequency, just used for error logging
> - *
> - * This function performs a noise floor calibration of the PHY and waits for
> - * it to complete. Then the noise floor value is compared to some maximum
> - * noise floor we consider valid.
> - *
> - * Note that this is different from what the madwifi HAL does: it reads the
> - * noise floor and afterwards initiates the calibration. Since the noise floor
> - * calibration can take some time to finish, depending on the current channel
> - * use, that avoids the occasional timeout warnings we are seeing now.
> - *
> - * See the following link for an Atheros patent on noise floor calibration:
> - * http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL \
> - * &p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7245893.PN.&OS=PN/7
> +static s32 ath5k_hw_read_measured_noise_floor(struct ath5k_hw *ah)
> +{
> + s32 val;
> +
> + val = ath5k_hw_reg_read(ah, AR5K_PHY_NF);
> + return sign_extend(AR5K_REG_MS(val, AR5K_PHY_NF_MINCCA_PWR), 9);
> +}
> +
> +void ath5k_hw_init_nfcal_hist(struct ath5k_hw *ah)
> +{
> + int i;
> +
> + ah->ah_nfcal_hist.index = 0;
> + for (i = 0; i < ATH5K_NF_CAL_HIST_MAX; i++)
> + ah->ah_nfcal_hist.nfval[i] = AR5K_TUNE_CCA_MAX_GOOD_VALUE;
> +}
> +
> +static void ath5k_hw_update_nfcal_hist(struct ath5k_hw *ah, s16 noise_floor)
> +{
> + struct ath5k_nfcal_hist *hist = &ah->ah_nfcal_hist;
> + hist->index = (hist->index + 1) & (ATH5K_NF_CAL_HIST_MAX-1);
> + hist->nfval[hist->index] = noise_floor;
> +}
> +
> +static s16 ath5k_hw_get_median_noise_floor(struct ath5k_hw *ah)
> +{
> + s16 sort[ATH5K_NF_CAL_HIST_MAX];
> + s16 tmp;
> + int i, j;
> +
> + memcpy(sort, ah->ah_nfcal_hist.nfval, sizeof(sort));
> + for (i = 0; i < ATH5K_NF_CAL_HIST_MAX - 1; i++) {
> + for (j = 1; j < ATH5K_NF_CAL_HIST_MAX - i; j++) {
> + if (sort[j] > sort[j-1]) {
> + tmp = sort[j];
> + sort[j] = sort[j-1];
> + sort[j-1] = tmp;
> + }
> + }
> + }
> + for (i = 0; i < ATH5K_NF_CAL_HIST_MAX; i++) {
> + ATH5K_DBG(ah->ah_sc, ATH5K_DEBUG_CALIBRATE,
> + "cal %d:%d\n", i, sort[i]);
> + }
> + return sort[(ATH5K_NF_CAL_HIST_MAX-1) / 2];
> +}
> +
> +/*
> + * When we tell the hardware to perform a noise floor calibration
> + * by setting the AR5K_PHY_AGCCTL_NF bit, it will periodically
> + * sample-and-hold the minimum noise level seen at the antennas.
> + * This value is then stored in a ring buffer of recently measured
> + * noise floor values so we have a moving window of the last few
> + * samples.
> *
> - * XXX: Since during noise floor calibration antennas are detached according to
> - * the patent, we should stop tx queues here.
> + * The median of the values in the history is then loaded into the
> + * hardware for its own use for RSSI and CCA measurements.
> */
> -int
> -ath5k_hw_noise_floor_calibration(struct ath5k_hw *ah, short freq)
> +void ath5k_hw_update_noise_floor(struct ath5k_hw *ah)
> {
> - int ret;
> - unsigned int i;
> - s32 noise_floor;
> + struct ath5k_eeprom_info *ee = &ah->ah_capabilities.cap_eeprom;
> + u32 val;
> + s16 nf, threshold;
> + u8 ee_mode;
>
> - /*
> - * Enable noise floor calibration
> - */
> - AR5K_REG_ENABLE_BITS(ah, AR5K_PHY_AGCCTL,
> - AR5K_PHY_AGCCTL_NF);
> + /* keep last value if calibration hasn't completed */
> + if (ath5k_hw_reg_read(ah, AR5K_PHY_AGCCTL) & AR5K_PHY_AGCCTL_NF) {
> + ATH5K_DBG(ah->ah_sc, ATH5K_DEBUG_CALIBRATE,
> + "NF did not complete in calibration window\n");
>
> - ret = ath5k_hw_register_timeout(ah, AR5K_PHY_AGCCTL,
> - AR5K_PHY_AGCCTL_NF, 0, false);
> - if (ret) {
> - ATH5K_ERR(ah->ah_sc,
> - "noise floor calibration timeout (%uMHz)\n", freq);
> - return -EAGAIN;
> + return;
> }
>
> - /* Wait until the noise floor is calibrated and read the value */
> - for (i = 20; i > 0; i--) {
> - mdelay(1);
> - noise_floor = ath5k_hw_reg_read(ah, AR5K_PHY_NF);
> - noise_floor = AR5K_PHY_NF_RVAL(noise_floor);
> - if (noise_floor & AR5K_PHY_NF_ACTIVE) {
> - noise_floor = AR5K_PHY_NF_AVAL(noise_floor);
> -
> - if (noise_floor <= AR5K_TUNE_NOISE_FLOOR)
> - break;
> - }
> + switch (ah->ah_current_channel->hw_value & CHANNEL_MODES) {
> + case CHANNEL_A:
> + case CHANNEL_T:
> + case CHANNEL_XR:
> + ee_mode = AR5K_EEPROM_MODE_11A;
> + break;
> + case CHANNEL_G:
> + case CHANNEL_TG:
> + ee_mode = AR5K_EEPROM_MODE_11G;
> + break;
> + default:
> + case CHANNEL_B:
> + ee_mode = AR5K_EEPROM_MODE_11B;
> + break;
> }
>
> - ATH5K_DBG_UNLIMIT(ah->ah_sc, ATH5K_DEBUG_CALIBRATE,
> - "noise floor %d\n", noise_floor);
>
> - if (noise_floor > AR5K_TUNE_NOISE_FLOOR) {
> - ATH5K_ERR(ah->ah_sc,
> - "noise floor calibration failed (%uMHz)\n", freq);
> - return -EAGAIN;
> + /* completed NF calibration, test threshold */
> + nf = ath5k_hw_read_measured_noise_floor(ah);
> + threshold = ee->ee_noise_floor_thr[ee_mode];
> +
> + if (nf > threshold) {
> + ATH5K_DBG(ah->ah_sc, ATH5K_DEBUG_CALIBRATE,
> + "noise floor failure detected; "
> + "read %d, threshold %d\n",
> + nf, threshold);
> +
> + nf = AR5K_TUNE_CCA_MAX_GOOD_VALUE;
> }
>
> - ah->ah_noise_floor = noise_floor;
> + ath5k_hw_update_nfcal_hist(ah, nf);
> + nf = ath5k_hw_get_median_noise_floor(ah);
>
> - return 0;
> + /* load noise floor (in .5 dBm) so the hardware will use it */
> + val = ath5k_hw_reg_read(ah, AR5K_PHY_NF) & ~AR5K_PHY_NF_M;
> + val |= (nf * 2) & AR5K_PHY_NF_M;
> + ath5k_hw_reg_write(ah, val, AR5K_PHY_NF);
> +
> + AR5K_REG_MASKED_BITS(ah, AR5K_PHY_AGCCTL, AR5K_PHY_AGCCTL_NF,
> + ~(AR5K_PHY_AGCCTL_NF_EN | AR5K_PHY_AGCCTL_NF_NOUPDATE));
> +
> + ath5k_hw_register_timeout(ah, AR5K_PHY_AGCCTL, AR5K_PHY_AGCCTL_NF,
> + 0, false);
> +
> + /*
> + * Load a high max CCA Power value (-50 dBm in .5 dBm units)
> + * so that we're not capped by the median we just loaded.
> + * This will be used as the initial value for the next noise
> + * floor calibration.
> + */
> + val = (val & ~AR5K_PHY_NF_M) | ((-50 * 2) & AR5K_PHY_NF_M);
> + ath5k_hw_reg_write(ah, val, AR5K_PHY_NF);
> + AR5K_REG_ENABLE_BITS(ah, AR5K_PHY_AGCCTL,
> + AR5K_PHY_AGCCTL_NF_EN |
> + AR5K_PHY_AGCCTL_NF_NOUPDATE |
> + AR5K_PHY_AGCCTL_NF);
> +
> + ah->ah_noise_floor = nf;
> +
> + ATH5K_DBG(ah->ah_sc, ATH5K_DEBUG_CALIBRATE,
> + "noise floor calibrated: %d\n", nf);
> }
>
> /*
> @@ -1287,7 +1358,7 @@ static int ath5k_hw_rf5110_calibrate(struct ath5k_hw *ah,
> return ret;
> }
>
> - ath5k_hw_noise_floor_calibration(ah, channel->center_freq);
> + ath5k_hw_update_noise_floor(ah);
>
> /*
> * Re-enable RX/TX and beacons
> @@ -1360,7 +1431,7 @@ done:
> * since noise floor calibration interrupts rx path while I/Q
> * calibration doesn't. We don't need to run noise floor calibration
> * as often as I/Q calibration.*/
> - ath5k_hw_noise_floor_calibration(ah, channel->center_freq);
> + ath5k_hw_update_noise_floor(ah);
>
> /* Initiate a gain_F calibration */
> ath5k_hw_request_rfgain_probe(ah);
> diff --git a/drivers/net/wireless/ath/ath5k/reg.h b/drivers/net/wireless/ath/ath5k/reg.h
> index debad07..7486da6 100644
> --- a/drivers/net/wireless/ath/ath5k/reg.h
> +++ b/drivers/net/wireless/ath/ath5k/reg.h
> @@ -2039,17 +2039,14 @@
> #define AR5K_PHY_AGCCTL_NF_NOUPDATE 0x00020000 /* Don't update nf automaticaly */
>
> /*
> - * PHY noise floor status register
> + * PHY noise floor status register (CCA = Clear Channel Assessment)
> */
> #define AR5K_PHY_NF 0x9864 /* Register address */
> -#define AR5K_PHY_NF_M 0x000001ff /* Noise floor mask */
> -#define AR5K_PHY_NF_ACTIVE 0x00000100 /* Noise floor calibration still active */
> -#define AR5K_PHY_NF_RVAL(_n) (((_n) >> 19) & AR5K_PHY_NF_M)
> -#define AR5K_PHY_NF_AVAL(_n) (-((_n) ^ AR5K_PHY_NF_M) + 1)
> -#define AR5K_PHY_NF_SVAL(_n) (((_n) & AR5K_PHY_NF_M) | (1 << 9))
> +#define AR5K_PHY_NF_M 0x000001ff /* Noise floor, written to hardware in 1/2 dBm units */
> +#define AR5K_PHY_NF_SVAL(_n) (((_n) & AR5K_PHY_NF_M) | (1 << 9))
> #define AR5K_PHY_NF_THRESH62 0x0007f000 /* Thresh62 -check ANI patent- (field) */
> #define AR5K_PHY_NF_THRESH62_S 12
> -#define AR5K_PHY_NF_MINCCA_PWR 0x0ff80000 /* ??? */
> +#define AR5K_PHY_NF_MINCCA_PWR 0x0ff80000 /* Minimum measured noise level, read from hardware in 1 dBm units */
> #define AR5K_PHY_NF_MINCCA_PWR_S 19
>
> /*
> diff --git a/drivers/net/wireless/ath/ath5k/reset.c b/drivers/net/wireless/ath/ath5k/reset.c
> index 34e13c7..aa05cf3 100644
> --- a/drivers/net/wireless/ath/ath5k/reset.c
> +++ b/drivers/net/wireless/ath/ath5k/reset.c
> @@ -1289,7 +1289,7 @@ int ath5k_hw_reset(struct ath5k_hw *ah, enum nl80211_iftype op_mode,
> * out and/or noise floor calibration might timeout.
> */
> AR5K_REG_ENABLE_BITS(ah, AR5K_PHY_AGCCTL,
> - AR5K_PHY_AGCCTL_CAL);
> + AR5K_PHY_AGCCTL_CAL | AR5K_PHY_AGCCTL_NF);
>
> /* At the same time start I/Q calibration for QAM constellation
> * -no need for CCK- */
> @@ -1310,21 +1310,6 @@ int ath5k_hw_reset(struct ath5k_hw *ah, enum nl80211_iftype op_mode,
> channel->center_freq);
> }
>
> - /*
> - * If we run NF calibration before AGC, it always times out.
> - * Binary HAL starts NF and AGC calibration at the same time
> - * and only waits for AGC to finish. Also if AGC or NF cal.
> - * times out, reset doesn't fail on binary HAL. I believe
> - * that's wrong because since rx path is routed to a detector,
> - * if cal. doesn't finish we won't have RX. Sam's HAL for AR5210/5211
> - * enables noise floor calibration after offset calibration and if noise
> - * floor calibration fails, reset fails. I believe that's
> - * a better approach, we just need to find a polling interval
> - * that suits best, even if reset continues we need to make
> - * sure that rx path is ready.
> - */
> - ath5k_hw_noise_floor_calibration(ah, channel->center_freq);
> -
> /* Restore antenna mode */
> ath5k_hw_set_antenna_mode(ah, ah->ah_ant_mode);
>
a) Please leave some comments to let people know that when nf
calibration runs antennas are detached (it measures the noise produced
from the card itself), that if we enable nf calibration before agc
calibration it always fails + the link to Atheros patent.
b) What about thresh62 ? Do we also need to update/rewrite this value
(we got it from EEPROM and write it on the register during reset) ?
Acked-by: Nick Kossifidis <mickflemm@xxxxxxxxx>
--
GPG ID: 0xD21DB2DB
As you read this post global entropy rises. Have Fun ;-)
Nick
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