Hello All,
I started using the "default" 2-wire coexistence without making any changes
in ath9k driver for AR9287. First executed "modprobe ath9k btcoex_enable = 1".I
used some print statements and came to know that 2-wire initialization
(ath9k_hw_btcoex_init_2wire()) and 2-wire enable
(ath9k_hw_btcoex_enable_2wire())routines were executed.
My understanding on 2-wire coex: Please correct me if I am wrong. When WLAN
activitiy (Tx or Rx; AR9287 is 2 x 2 MIMO) is in progress, WLAN_ACTIVE is
asserted. If Bluetooth wants to transmit any packets, than BT_ACTIVE line has
to be asserted (pull high). Then WLAN should buffer any transmissions (however
there can be receptions/ACK) and allow Bluetooth to transmit packets. AR9287
stops transmission when BT_ACTIVE is true.
Based on the following code snippet, from hw.c:
if (common->btcoex_enabled) {
if (AR_SREV_9300_20_OR_LATER(ah)) {
btcoex_hw->scheme = ATH_BTCOEX_CFG_3WIRE;
btcoex_hw->btactive_gpio = ATH_BTACTIVE_GPIO_9300;
btcoex_hw->wlanactive_gpio = ATH_WLANACTIVE_GPIO_9300;
btcoex_hw->btpriority_gpio = ATH_BTPRIORITY_GPIO_9300;
} else if (AR_SREV_9280_20_OR_LATER(ah)) {
btcoex_hw->btactive_gpio = ATH_BTACTIVE_GPIO_9280;
btcoex_hw->wlanactive_gpio = ATH_WLANACTIVE_GPIO_9280;
if (AR_SREV_9285(ah)) {
btcoex_hw->scheme = ATH_BTCOEX_CFG_3WIRE;
btcoex_hw->btpriority_gpio =
ATH_BTPRIORITY_GPIO_9285;
} else {
btcoex_hw->scheme = ATH_BTCOEX_CFG_2WIRE;
}
}
} else {
btcoex_hw->scheme = ATH_BTCOEX_CFG_NONE;
}
I understand that ATH_BTCOEX_CFG_2_WIRE, ATH_BTACTIVE_GPIO_9280 (GPIO6 as per
btcoex.h) and ATH_WLANACTIVE_GPIO_9280 (GPIO5 as per btcoex.h) are used.
I next started monitoring GPIO5 on oscillaoscope to see WLAN activity and I
could see a lot of pulse trains. Next in order to simulate high priority BT
traffic, I pulled the line GPIO6 high. But I did not see any change in WLAN
activity as I could continue to see the pulse trains. My expectation was that
there should not be any WLAN activity and hence no pulses. Please guide if I am
missing anything?
Thanks & regards
Sandeep_______________________________________________
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