Re: [PATCH] mt76: mt7615: add support for per-chain signal strength reporting

From: Sebastian Gottschall
Date: Mon Jun 10 2019 - 00:52:29 EST


okay. curious is, that my variant works with sane results too.
i will test your variant and check the results

Sebastian

Am 10.06.2019 um 06:22 schrieb Ryder Lee:
On Mon, 2019-06-10 at 10:09 +0800, Ryder Lee wrote:
On Sun, 2019-06-09 at 16:44 +0200, Sebastian Gottschall wrote:
according to my findings

MT_RXV4_RCPI1 is part of rx descriptor 4 and not 3
so it must be rxdg4 = rxd[4] etc.
RXV start from 1 in the code.

That is: RXV1 <-> rxdg0, RXV2 <-> rxdg1 ...so RXV4 <-> rxdg3

however rxdg3 contains MT_RXV3_IB_RSSIRX which can be used for signal calculation.
i already wrote a similar code for this driver which i sended to felix a long time ago.
my variant looks like
status->signal = (FIELD_GET(MT_RXV3_IB_RSSIRX, rxdg3) - 220) / 2;
status->chain_signal[0] = (FIELD_GET(MT_RXV4_RCPI0, rxdg4) - 220) / 2;
status->chain_signal[1] = (FIELD_GET(MT_RXV4_RCPI1, rxdg4) - 220) / 2;
status->chain_signal[2] = (FIELD_GET(MT_RXV4_RCPI2, rxdg4) - 220) / 2;
status->chain_signal[3] = (FIELD_GET(MT_RXV4_RCPI3, rxdg4) - 220) / 2;
mt7615 actually doesn't use in-band RSSI for signal calculation, but it
occurs to me that i should modify the code to compare per-chain's
signal. Something like this:

status->chain_signal[0] = to_rssi(MT_RXV4_RCPI0, rxdg3);
status->chain_signal[1] = to_rssi(MT_RXV4_RCPI1, rxdg3);
status->chain_signal[2] = to_rssi(MT_RXV4_RCPI2, rxdg3);
status->chain_signal[3] = to_rssi(MT_RXV4_RCPI3, rxdg3);
status->signal = status->chain_signal[0];

switch (status->chains) {
case 0xf:
status->signal = max(status->signal,
status->chain_signal[3]);
case 0x7:
status->signal = max(status->signal,
status->chain_signal[2]);
case 0x3:
status->signal = max(status->signal,
status->chain_signal[1]);
break;
default:
break;
}


I could send a v2 or you can take care of that.

Ryder