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);
--
1.6.2.5
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