ath5k: Update gain_F calibration code and add documentation
* Update and cleanup rf gain optimization code
* Add comments and refferences to docs and use sane function names
* Use only step index on ath5k_gain, no need to have a pointer to
the current step since we can determine te step from it's index,
this also allows us to put all other structs on rfgain.h and cleanup
ath5k.h a little
* No need for ah_rfgain variable, we use ah_gain.g_state for everything
* Tested on RF2112B chip but gain_F calibration is not yet done
(we will finish this on the next patch where we'll rewrite rf-buffer
handling)
* Use initial rf gain settings for 2316 and 2317 SoCs introduced on a previous patch
It seems big but it's mostly cleanup, very few functional changes have been made on phy.c
Signed-off-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath5k/phy.c b/drivers/net/wireless/ath5k/phy.c
index 5021749..2543a71 100644
--- a/drivers/net/wireless/ath5k/phy.c
+++ b/drivers/net/wireless/ath5k/phy.c
@@ -78,10 +78,104 @@
return data;
}
-static u32 ath5k_hw_rfregs_gainf_corr(struct ath5k_hw *ah)
+/**********************\
+* RF Gain optimization *
+\**********************/
+
+/*
+ * This code is used to optimize rf gain on different environments
+ * (temprature mostly) based on feedback from a power detector.
+ *
+ * It's only used on RF5111 and RF5112, later RF chips seem to have
+ * auto adjustment on hw -notice they have a much smaller BANK 7 and
+ * no gain optimization ladder-.
+ *
+ * For more infos check out this patent doc
+ * http://www.freepatentsonline.com/7400691.html
+ *
+ * This paper describes power drops as seen on the receiver due to
+ * probe packets
+ * http://www.cnri.dit.ie/publications/ICT08%20-%20Practical%20Issues
+ * %20of%20Power%20Control.pdf
+ *
+ * And this is the MadWiFi bug entry related to the above
+ * http://madwifi-project.org/ticket/1659
+ * with various measurements and diagrams
+ *
+ * TODO: Deal with power drops due to probes by setting an apropriate
+ * tx power on the probe packets ! Make this part of the calibration process.
+ */
+
+/* Initialize ah_gain durring attach */
+int ath5k_hw_rfgain_opt_init(struct ath5k_hw *ah)
+{
+ /* Initialize the gain optimization values */
+ switch (ah->ah_radio) {
+ case AR5K_RF5111:
+ ah->ah_gain.g_step_idx = rfgain_opt_5111.go_default;
+ ah->ah_gain.g_low = 20;
+ ah->ah_gain.g_high = 35;
+ ah->ah_gain.g_state = AR5K_RFGAIN_ACTIVE;
+ break;
+ case AR5K_RF5112:
+ ah->ah_gain.g_step_idx = rfgain_opt_5112.go_default;
+ ah->ah_gain.g_low = 20;
+ ah->ah_gain.g_high = 85;
+ ah->ah_gain.g_state = AR5K_RFGAIN_ACTIVE;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/* Schedule a gain probe check on the next transmited packet.
+ * That means our next packet is going to be sent with lower
+ * tx power and a Peak to Average Power Detector (PAPD) will try
+ * to measure the gain.
+ *
+ * TODO: Use propper tx power setting for the probe packet so
+ * that we don't observe a serious power drop on the receiver
+ *
+ * XXX: How about forcing a tx packet (bypassing PCU arbitrator etc)
+ * just after we enable the probe so that we don't mess with
+ * standard traffic ? Maybe it's time to use sw interrupts and
+ * a probe tasklet !!!
+ */
+static void ath5k_hw_request_rfgain_probe(struct ath5k_hw *ah)
+{
+
+ /* Skip if gain calibration is inactive or
+ * we already handle a probe request */
+ if (ah->ah_gain.g_state != AR5K_RFGAIN_ACTIVE)
+ return;
+
+ ath5k_hw_reg_write(ah, AR5K_REG_SM(ah->ah_txpower.txp_max,
+ AR5K_PHY_PAPD_PROBE_TXPOWER) |
+ AR5K_PHY_PAPD_PROBE_TX_NEXT, AR5K_PHY_PAPD_PROBE);
+
+ ah->ah_gain.g_state = AR5K_RFGAIN_READ_REQUESTED;
+
+}
+
+/* Calculate gain_F measurement correction
+ * based on the current step for RF5112 rev. 2 */
+static u32 ath5k_hw_rf_gainf_corr(struct ath5k_hw *ah)
{
u32 mix, step;
u32 *rf;
+ const struct ath5k_gain_opt *go;
+ const struct ath5k_gain_opt_step *g_step;
+
+ /* Only RF5112 Rev. 2 supports it */
+ if ((ah->ah_radio != AR5K_RF5112) ||
+ (ah->ah_radio_5ghz_revision <= AR5K_SREV_RAD_5112A))
+ return 0;
+
+ go = &rfgain_opt_5112;
+
+ g_step = &go->go_step[ah->ah_gain.g_step_idx];
if (ah->ah_rf_banks == NULL)
return 0;
@@ -89,11 +183,15 @@
rf = ah->ah_rf_banks;
ah->ah_gain.g_f_corr = 0;
+ /* No VGA (Variable Gain Amplifier) override, skip */
if (ath5k_hw_rfregs_op(rf, ah->ah_offset[7], 0, 1, 36, 0, false) != 1)
return 0;
+ /* Mix gain stepping */
step = ath5k_hw_rfregs_op(rf, ah->ah_offset[7], 0, 4, 32, 0, false);
- mix = ah->ah_gain.g_step->gos_param[0];
+
+ /* Mix gain override */
+ mix = g_step->gos_param[0];
switch (mix) {
case 3:
@@ -113,9 +211,13 @@
return ah->ah_gain.g_f_corr;
}
-static bool ath5k_hw_rfregs_gain_readback(struct ath5k_hw *ah)
+/* Check if current gain_F measurement is in the range of our
+ * power detector windows. If we get a measurement outside range
+ * we know it's not accurate (detectors can't measure anything outside
+ * their detection window) so we must ignore it */
+static bool ath5k_hw_rf_check_gainf_readback(struct ath5k_hw *ah)
{
- u32 step, mix, level[4];
+ u32 step, mix_ovr, level[4];
u32 *rf;
if (ah->ah_rf_banks == NULL)
@@ -127,20 +229,20 @@
step = ath5k_hw_rfregs_op(rf, ah->ah_offset[7], 0, 6, 37, 0,
false);
level[0] = 0;
- level[1] = (step == 0x3f) ? 0x32 : step + 4;
- level[2] = (step != 0x3f) ? 0x40 : level[0];
- level[3] = level[2] + 0x32;
+ level[1] = (step == 63) ? 50 : step + 4;
+ level[2] = (step != 63) ? 64 : level[0];
+ level[3] = level[2] + 50 ;
ah->ah_gain.g_high = level[3] -
- (step == 0x3f ? AR5K_GAIN_DYN_ADJUST_HI_MARGIN : -5);
+ (step == 63 ? AR5K_GAIN_DYN_ADJUST_HI_MARGIN : -5);
ah->ah_gain.g_low = level[0] +
- (step == 0x3f ? AR5K_GAIN_DYN_ADJUST_LO_MARGIN : 0);
+ (step == 63 ? AR5K_GAIN_DYN_ADJUST_LO_MARGIN : 0);
} else {
- mix = ath5k_hw_rfregs_op(rf, ah->ah_offset[7], 0, 1, 36, 0,
+ mix_ovr = ath5k_hw_rfregs_op(rf, ah->ah_offset[7], 0, 1, 36, 0,
false);
level[0] = level[2] = 0;
- if (mix == 1) {
+ if (mix_ovr == 1) {
level[1] = level[3] = 83;
} else {
level[1] = level[3] = 107;
@@ -154,9 +256,12 @@
ah->ah_gain.g_current <= level[3]);
}
-static s32 ath5k_hw_rfregs_gain_adjust(struct ath5k_hw *ah)
+/* Perform gain_F adjustment by choosing the right set
+ * of parameters from rf gain optimization ladder */
+static s8 ath5k_hw_rf_gainf_adjust(struct ath5k_hw *ah)
{
const struct ath5k_gain_opt *go;
+ const struct ath5k_gain_opt_step *g_step;
int ret = 0;
switch (ah->ah_radio) {
@@ -170,35 +275,39 @@
return 0;
}
- ah->ah_gain.g_step = &go->go_step[ah->ah_gain.g_step_idx];
+ g_step = &go->go_step[ah->ah_gain.g_step_idx];
if (ah->ah_gain.g_current >= ah->ah_gain.g_high) {
+
+ /* Reached maximum */
if (ah->ah_gain.g_step_idx == 0)
return -1;
+
for (ah->ah_gain.g_target = ah->ah_gain.g_current;
ah->ah_gain.g_target >= ah->ah_gain.g_high &&
ah->ah_gain.g_step_idx > 0;
- ah->ah_gain.g_step =
- &go->go_step[ah->ah_gain.g_step_idx])
+ g_step = &go->go_step[ah->ah_gain.g_step_idx])
ah->ah_gain.g_target -= 2 *
(go->go_step[--(ah->ah_gain.g_step_idx)].gos_gain -
- ah->ah_gain.g_step->gos_gain);
+ g_step->gos_gain);
ret = 1;
goto done;
}
if (ah->ah_gain.g_current <= ah->ah_gain.g_low) {
+
+ /* Reached minimum */
if (ah->ah_gain.g_step_idx == (go->go_steps_count - 1))
return -2;
+
for (ah->ah_gain.g_target = ah->ah_gain.g_current;
ah->ah_gain.g_target <= ah->ah_gain.g_low &&
ah->ah_gain.g_step_idx < go->go_steps_count-1;
- ah->ah_gain.g_step =
- &go->go_step[ah->ah_gain.g_step_idx])
+ g_step = &go->go_step[ah->ah_gain.g_step_idx])
ah->ah_gain.g_target -= 2 *
(go->go_step[++ah->ah_gain.g_step_idx].gos_gain -
- ah->ah_gain.g_step->gos_gain);
+ g_step->gos_gain);
ret = 2;
goto done;
@@ -213,6 +322,135 @@
return ret;
}
+/* Main callback for thermal rf gain calibration engine
+ * Check for a new gain reading and schedule an adjustment
+ * if needed.
+ *
+ * TODO: Use sw interrupt to schedule reset if gain_F needs
+ * adjustment */
+enum ath5k_rfgain ath5k_hw_gainf_calibrate(struct ath5k_hw *ah)
+{
+ u32 data, type;
+ struct ath5k_eeprom_info *ee = &ah->ah_capabilities.cap_eeprom;
+
+ ATH5K_TRACE(ah->ah_sc);
+
+ if (ah->ah_rf_banks == NULL ||
+ ah->ah_gain.g_state == AR5K_RFGAIN_INACTIVE)
+ return AR5K_RFGAIN_INACTIVE;
+
+ /* No check requested, either engine is inactive
+ * or an adjustment is already requested */
+ if (ah->ah_gain.g_state != AR5K_RFGAIN_READ_REQUESTED)
+ goto done;
+
+ /* Read the PAPD (Peak to Average Power Detector)
+ * register */
+ data = ath5k_hw_reg_read(ah, AR5K_PHY_PAPD_PROBE);
+
+ /* No probe is scheduled, read gain_F measurement */
+ if (!(data & AR5K_PHY_PAPD_PROBE_TX_NEXT)) {
+ ah->ah_gain.g_current = data >> AR5K_PHY_PAPD_PROBE_GAINF_S;
+ type = AR5K_REG_MS(data, AR5K_PHY_PAPD_PROBE_TYPE);
+
+ /* If tx packet is CCK correct the gain_F measurement
+ * by cck ofdm gain delta */
+ if (type == AR5K_PHY_PAPD_PROBE_TYPE_CCK) {
+ if (ah->ah_radio_5ghz_revision >= AR5K_SREV_RAD_5112A)
+ ah->ah_gain.g_current +=
+ ee->ee_cck_ofdm_gain_delta;
+ else
+ ah->ah_gain.g_current +=
+ AR5K_GAIN_CCK_PROBE_CORR;
+ }
+
+ /* Further correct gain_F measurement for
+ * RF5112A radios */
+ if (ah->ah_radio_5ghz_revision >= AR5K_SREV_RAD_5112A) {
+ ath5k_hw_rf_gainf_corr(ah);
+ ah->ah_gain.g_current =
+ ah->ah_gain.g_current >= ah->ah_gain.g_f_corr ?
+ (ah->ah_gain.g_current-ah->ah_gain.g_f_corr) :
+ 0;
+ }
+
+ /* Check if measurement is ok and if we need
+ * to adjust gain, schedule a gain adjustment,
+ * else switch back to the acive state */
+ if (ath5k_hw_rf_check_gainf_readback(ah) &&
+ AR5K_GAIN_CHECK_ADJUST(&ah->ah_gain) &&
+ ath5k_hw_rf_gainf_adjust(ah)) {
+ ah->ah_gain.g_state = AR5K_RFGAIN_NEED_CHANGE;
+ } else {
+ ah->ah_gain.g_state = AR5K_RFGAIN_ACTIVE;
+ }
+ }
+
+done:
+ return ah->ah_gain.g_state;
+}
+
+/* Write initial rf gain table to set the RF sensitivity
+ * this one works on all RF chips and has nothing to do
+ * with gain_F calibration */
+int ath5k_hw_rfgain_init(struct ath5k_hw *ah, unsigned int freq)
+{
+ const struct ath5k_ini_rfgain *ath5k_rfg;
+ unsigned int i, size;
+
+ switch (ah->ah_radio) {
+ case AR5K_RF5111:
+ ath5k_rfg = rfgain_5111;
+ size = ARRAY_SIZE(rfgain_5111);
+ break;
+ case AR5K_RF5112:
+ ath5k_rfg = rfgain_5112;
+ size = ARRAY_SIZE(rfgain_5112);
+ break;
+ case AR5K_RF2413:
+ ath5k_rfg = rfgain_2413;
+ size = ARRAY_SIZE(rfgain_2413);
+ break;
+ case AR5K_RF2316:
+ ath5k_rfg = rfgain_2316;
+ size = ARRAY_SIZE(rfgain_2316);
+ break;
+ case AR5K_RF5413:
+ ath5k_rfg = rfgain_5413;
+ size = ARRAY_SIZE(rfgain_5413);
+ break;
+ case AR5K_RF2317:
+ case AR5K_RF2425:
+ ath5k_rfg = rfgain_2425;
+ size = ARRAY_SIZE(rfgain_2425);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ switch (freq) {
+ case AR5K_INI_RFGAIN_2GHZ:
+ case AR5K_INI_RFGAIN_5GHZ:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ for (i = 0; i < size; i++) {
+ AR5K_REG_WAIT(i);
+ ath5k_hw_reg_write(ah, ath5k_rfg[i].rfg_value[freq],
+ (u32)ath5k_rfg[i].rfg_register);
+ }
+
+ return 0;
+}
+
+
+
+/********************\
+* RF Registers setup *
+\********************/
+
/*
* Read EEPROM Calibration data, modify RF Banks and Initialize RF5111
*/
@@ -311,6 +549,8 @@
ath5k_hw_reg_write(ah, rf[i], rfb_5111[i].rfb_ctrl_register);
}
+ ah->ah_gain.g_state = AR5K_RFGAIN_ACTIVE;
+
return 0;
}
@@ -407,6 +647,9 @@
for (i = 0; i < rf_size; i++)
ath5k_hw_reg_write(ah, rf[i], rf_ini[i].rfb_ctrl_register);
+
+ ah->ah_gain.g_state = AR5K_RFGAIN_ACTIVE;
+
return 0;
}
@@ -536,125 +779,12 @@
}
ret = func(ah, channel, mode);
- if (!ret)
- ah->ah_rf_gain = AR5K_RFGAIN_INACTIVE;
return ret;
}
-int ath5k_hw_rfgain(struct ath5k_hw *ah, unsigned int freq)
-{
- const struct ath5k_ini_rfgain *ath5k_rfg;
- unsigned int i, size;
- switch (ah->ah_radio) {
- case AR5K_RF5111:
- ath5k_rfg = rfgain_5111;
- size = ARRAY_SIZE(rfgain_5111);
- break;
- case AR5K_RF5112:
- ath5k_rfg = rfgain_5112;
- size = ARRAY_SIZE(rfgain_5112);
- break;
- case AR5K_RF5413:
- ath5k_rfg = rfgain_5413;
- size = ARRAY_SIZE(rfgain_5413);
- break;
- case AR5K_RF2413:
- ath5k_rfg = rfgain_2413;
- size = ARRAY_SIZE(rfgain_2413);
- break;
- case AR5K_RF2425:
- ath5k_rfg = rfgain_2425;
- size = ARRAY_SIZE(rfgain_2425);
- break;
- default:
- return -EINVAL;
- }
- switch (freq) {
- case AR5K_INI_RFGAIN_2GHZ:
- case AR5K_INI_RFGAIN_5GHZ:
- break;
- default:
- return -EINVAL;
- }
-
- for (i = 0; i < size; i++) {
- AR5K_REG_WAIT(i);
- ath5k_hw_reg_write(ah, ath5k_rfg[i].rfg_value[freq],
- (u32)ath5k_rfg[i].rfg_register);
- }
-
- return 0;
-}
-
-enum ath5k_rfgain ath5k_hw_get_rf_gain(struct ath5k_hw *ah)
-{
- u32 data, type;
-
- ATH5K_TRACE(ah->ah_sc);
-
- if (ah->ah_rf_banks == NULL || !ah->ah_gain.g_active ||
- ah->ah_version <= AR5K_AR5211)
- return AR5K_RFGAIN_INACTIVE;
-
- if (ah->ah_rf_gain != AR5K_RFGAIN_READ_REQUESTED)
- goto done;
-
- data = ath5k_hw_reg_read(ah, AR5K_PHY_PAPD_PROBE);
-
- if (!(data & AR5K_PHY_PAPD_PROBE_TX_NEXT)) {
- ah->ah_gain.g_current = data >> AR5K_PHY_PAPD_PROBE_GAINF_S;
- type = AR5K_REG_MS(data, AR5K_PHY_PAPD_PROBE_TYPE);
-
- if (type == AR5K_PHY_PAPD_PROBE_TYPE_CCK)
- ah->ah_gain.g_current += AR5K_GAIN_CCK_PROBE_CORR;
-
- if (ah->ah_radio >= AR5K_RF5112) {
- ath5k_hw_rfregs_gainf_corr(ah);
- ah->ah_gain.g_current =
- ah->ah_gain.g_current >= ah->ah_gain.g_f_corr ?
- (ah->ah_gain.g_current-ah->ah_gain.g_f_corr) :
- 0;
- }
-
- if (ath5k_hw_rfregs_gain_readback(ah) &&
- AR5K_GAIN_CHECK_ADJUST(&ah->ah_gain) &&
- ath5k_hw_rfregs_gain_adjust(ah))
- ah->ah_rf_gain = AR5K_RFGAIN_NEED_CHANGE;
- }
-
-done:
- return ah->ah_rf_gain;
-}
-
-int ath5k_hw_set_rfgain_opt(struct ath5k_hw *ah)
-{
- /* Initialize the gain optimization values */
- switch (ah->ah_radio) {
- case AR5K_RF5111:
- ah->ah_gain.g_step_idx = rfgain_opt_5111.go_default;
- ah->ah_gain.g_step =
- &rfgain_opt_5111.go_step[ah->ah_gain.g_step_idx];
- ah->ah_gain.g_low = 20;
- ah->ah_gain.g_high = 35;
- ah->ah_gain.g_active = 1;
- break;
- case AR5K_RF5112:
- ah->ah_gain.g_step_idx = rfgain_opt_5112.go_default;
- ah->ah_gain.g_step =
- &rfgain_opt_5112.go_step[ah->ah_gain.g_step_idx];
- ah->ah_gain.g_low = 20;
- ah->ah_gain.g_high = 85;
- ah->ah_gain.g_active = 1;
- break;
- default:
- return -EINVAL;
- }
-
- return 0;
-}
/**************************\
PHY/RF channel functions
@@ -1176,13 +1306,8 @@
* as often as I/Q calibration.*/
ath5k_hw_noise_floor_calibration(ah, channel->center_freq);
- /* Request RF gain */
- if (channel->hw_value & CHANNEL_5GHZ) {
- ath5k_hw_reg_write(ah, AR5K_REG_SM(ah->ah_txpower.txp_max,
- AR5K_PHY_PAPD_PROBE_TXPOWER) |
- AR5K_PHY_PAPD_PROBE_TX_NEXT, AR5K_PHY_PAPD_PROBE);
- ah->ah_rf_gain = AR5K_RFGAIN_READ_REQUESTED;
- }
+ /* Initiate a gain_F calibration */
+ ath5k_hw_request_rfgain_probe(ah);
return 0;
}