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mwx: implement RSSI
On Fri, May 01, 2026 at 05:00:48PM -0500, Benjamin Lee McQueen wrote:
> hi tech@,
>
> attached is a diff that implements RSSI for the MediaTek MT7921 network
> card.
>
> tested on a MT7921.
>
> -ben
> --- sys/dev/pci/if_mwx.c Fri Aug 1 08:37:06 2025
> +++ /usr/src/sys/dev/pci/if_mwx.c Mon Mar 9 18:45:35 2026
> @@ -1019,7 +1019,7 @@
> htole16(ic->ic_channels[rxi.rxi_chan].ic_freq);
> tap->wr_chan_flags =
> ic->ic_channels[rxi.rxi_chan].ic_flags;
> - tap->wr_dbm_antsignal = 0;
> + tap->wr_dbm_antsignal = rxi.rxi_rssi;
> bpf_mtap_hdr(sc->sc_drvbpf, tap, sc->sc_rxtap_len, m,
> BPF_DIRECTION_IN);
> }
> @@ -1029,7 +1029,6 @@
> ni = ieee80211_find_rxnode(ic, wh);
>
> /* send the frame to the 802.11 layer */
> - /* TODO MAYBE rxi.rxi_rssi = rssi; */
> ieee80211_inputm(ifp, m, ni, &rxi, ml);
>
> /* node is no longer needed */
> @@ -4225,11 +4224,13 @@
> struct ieee80211_rxinfo *rxi)
> {
> struct ieee80211com *ic = &sc->sc_ic;
> - uint32_t *rxd, rxd0, rxd1, rxd2, rxd3, rxd4;
> + uint32_t *rxd, *rxv = NULL;
> + uint32_t rxd0, rxd1, rxd2, rxd3, rxd4;
> // uint32_t mode = 0;
> uint16_t hdr_gap /*, seq_ctrl = 0, fc = 0 */;
> uint8_t chfnum, remove_pad /*, qos_ctl = 0, amsdu_info */;
> int idx, unicast, num_rxd = 6;
> + int i;
> // bool insert_ccmp_hdr = false;
>
> if (m->m_len < num_rxd * sizeof(uint32_t))
> @@ -4308,16 +4309,53 @@
>
> rxd += 6;
>
> - if (rxd1 & MT_RXD1_NORMAL_GROUP_4)
> + if (rxd1 & MT_RXD1_NORMAL_GROUP_4) {
> num_rxd += 4;
> - if (rxd1 & MT_RXD1_NORMAL_GROUP_1)
> + rxd += 4;
> + }
> + if (rxd1 & MT_RXD1_NORMAL_GROUP_1) {
> num_rxd += 4;
> - if (rxd1 & MT_RXD1_NORMAL_GROUP_2)
> + rxd += 4;
> + }
> + if (rxd1 & MT_RXD1_NORMAL_GROUP_2) {
> num_rxd += 2;
> - if (rxd1 & MT_RXD1_NORMAL_GROUP_3)
> + rxd += 2;
> + }
> + if (rxd1 & MT_RXD1_NORMAL_GROUP_3) {
> + uint32_t v0, v1;
> + int8_t chain[4], signal;
> +
> + rxv = rxd;
> num_rxd += 2;
> - if (rxd1 & MT_RXD1_NORMAL_GROUP_5)
> - num_rxd += 18;
> + rxd += 2;
> +
> + v0 = le32toh(rxv[0]); /* XXX not implemented yet */
> + v1 = le32toh(rxv[1]);
> +
> + if (rxd1 & MT_RXD1_NORMAL_GROUP_5) {
> + num_rxd += 18;
> + rxd += 6;
> + rxv = rxd;
> + v1 = le32toh(rxv[0]);
> + rxd += 12;
> + }
> +
> +
> + chain[0] = rcpi_to_rssi(MT_PRXV_RCPI0, v1);
> + chain[1] = rcpi_to_rssi(MT_PRXV_RCPI1, v1);
> + chain[2] = rcpi_to_rssi(MT_PRXV_RCPI2, v1);
> + chain[3] = rcpi_to_rssi(MT_PRXV_RCPI3, v1);
> +
> + signal = -128;
> + for (i = 0; i < sc->sc_capa.num_streams; i++) {
> + if (!(sc->sc_capa.antenna_mask & BIT(i)))
> + continue;
> + if (chain[i] >= 0)
> + continue;
> + signal = MAX(signal, chain[i]);
> + }
> + rxi->rxi_rssi = signal;
> + }
>
> if (m->m_len < num_rxd * sizeof(uint32_t))
> return -1;
> --- sys/dev/pci/if_mwxreg.h Wed May 22 02:38:57 2024
> +++ /usr/src/sys/dev/pci/if_mwxreg.h Mon Mar 9 18:40:42 2026
> @@ -16,6 +16,11 @@
> * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
> */
>
> +/* FROM LINUX */
> +#define BIT(x) (1 << (x))
> +#define FIELD_GET(mask, reg) (((reg) & (mask)) >> (__builtin_ctz(mask)))
> +#define GENMASK(h, l) (((~0U) >> (31 - (h))) & (~0U << (l)))
> +
> /* MCU WFDMA1 */
> #define MT_MCU_WFDMA1_BASE 0x3000
>
> @@ -1401,6 +1406,12 @@
> #define PHY_TYPE_BIT_HT (1U << 4)
> #define PHY_TYPE_BIT_VHT (1U << 5)
> #define PHY_TYPE_BIT_HE (1U << 6)
> +
> +/* P-RXV DW0 */
> +#define MT_PRXV_RCPI3 GENMASK(31, 24)
> +#define MT_PRXV_RCPI2 GENMASK(23, 16)
> +#define MT_PRXV_RCPI1 GENMASK(15, 8)
> +#define MT_PRXV_RCPI0 GENMASK(7, 0)
>
> #define rssi_to_rcpi(rssi) (2 * (rssi) + 220)
> #define rcpi_to_rssi(field, rxv) ((FIELD_GET(field, rxv) - 220) / 2)
Please do not introduce BIT, FIELD_GET and GENMASK and instead replace
them similar to how it is done in other places. You normally want a
XY_MASK and XY_SHIFT value.
I know that I have not converted all values yet in the header but I really
don't want those macros.
--
:wq Claudio
mwx: implement RSSI