wifi: rtw88: Fix the RX aggregation in USB 3 mode

RTL8822CU, RTL8822BU, and RTL8821CU don't need BIT_EN_PRE_CALC.
In fact, RTL8822BU in USB 3 mode doesn't pass all the frames to the
driver, resulting in much lower download speed than normal:

$ iperf3 -c 192.168.0.1 -R
Connecting to host 192.168.0.1, port 5201
Reverse mode, remote host 192.168.0.1 is sending
[  5] local 192.168.0.50 port 43062 connected to 192.168.0.1 port 5201
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec  26.9 MBytes   225 Mbits/sec
[  5]   1.00-2.00   sec  7.50 MBytes  62.9 Mbits/sec
[  5]   2.00-3.00   sec  8.50 MBytes  71.3 Mbits/sec
[  5]   3.00-4.00   sec  8.38 MBytes  70.3 Mbits/sec
[  5]   4.00-5.00   sec  7.75 MBytes  65.0 Mbits/sec
[  5]   5.00-6.00   sec  8.00 MBytes  67.1 Mbits/sec
[  5]   6.00-7.00   sec  8.00 MBytes  67.1 Mbits/sec
[  5]   7.00-8.00   sec  7.75 MBytes  65.0 Mbits/sec
[  5]   8.00-9.00   sec  7.88 MBytes  66.1 Mbits/sec
[  5]   9.00-10.00  sec  7.88 MBytes  66.1 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.02  sec   102 MBytes  85.1 Mbits/sec  224             sender
[  5]   0.00-10.00  sec  98.6 MBytes  82.7 Mbits/sec                  receiver

Don't set BIT_EN_PRE_CALC. Then the speed is much better:

% iperf3 -c 192.168.0.1 -R
Connecting to host 192.168.0.1, port 5201
Reverse mode, remote host 192.168.0.1 is sending
[  5] local 192.168.0.50 port 39000 connected to 192.168.0.1 port 5201
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec  52.8 MBytes   442 Mbits/sec
[  5]   1.00-2.00   sec  71.9 MBytes   603 Mbits/sec
[  5]   2.00-3.00   sec  74.8 MBytes   627 Mbits/sec
[  5]   3.00-4.00   sec  75.9 MBytes   636 Mbits/sec
[  5]   4.00-5.00   sec  76.0 MBytes   638 Mbits/sec
[  5]   5.00-6.00   sec  74.1 MBytes   622 Mbits/sec
[  5]   6.00-7.00   sec  74.0 MBytes   621 Mbits/sec
[  5]   7.00-8.00   sec  76.0 MBytes   638 Mbits/sec
[  5]   8.00-9.00   sec  74.4 MBytes   624 Mbits/sec
[  5]   9.00-10.00  sec  63.9 MBytes   536 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec   717 MBytes   601 Mbits/sec   24             sender
[  5]   0.00-10.00  sec   714 MBytes   599 Mbits/sec                  receiver

Fixes: 002a5db ("wifi: rtw88: Enable USB RX aggregation for 8822c/8822b/8821c")
Signed-off-by: Bitterblue Smith <[email protected]>
Acked-by: Ping-Ke Shih <[email protected]>
Signed-off-by: Kalle Valo <[email protected]>
Link: https://patch.msgid.link/[email protected]

Author: Bitterblue Smith

drivers/net/wireless/realtek/rtw88/usb.c

@@ -771,7 +771,6 @@ static void rtw_usb_dynamic_rx_agg_v1(struct rtw_dev *rtwdev, bool enable)
 	u8 size, timeout;
 	u16 val16;
 
-	rtw_write32_set(rtwdev, REG_RXDMA_AGG_PG_TH, BIT_EN_PRE_CALC);
 	rtw_write8_set(rtwdev, REG_TXDMA_PQ_MAP, BIT_RXDMA_AGG_EN);
 	rtw_write8_clr(rtwdev, REG_RXDMA_AGG_PG_TH + 3, BIT(7));