Kestrel 8852C passive noise floor: physts measurement bring-up + bare-physts report

hal/halbb/g6/kestrel_halbb_glue.c

@@ -74,6 +74,21 @@ void kestrel_halbb_rx_bringup(struct kestrel_halbb_ctx *ctx) {
   /* Enable both RX chains (rx_path_en). Vendor core dispatcher; its 8852C
    * case passes hal_com->dbcc_en (0 here) — same as the direct call did. */
   halbb_ctrl_rx_path(bb, RF_PATH_AB, HW_PHY_0);
+
+  /* 8852C physts MEASUREMENT bring-up. Devourer's minimal halbb bring-up runs
+   * only halbb_init_reg (BB table) + this, skipping the vendor's
+   * halbb_dm_init_per_phy measurement inits. On the 8852B the physts engine
+   * fills reports anyway (its table covers it); on the 8852C the reports arrive
+   * EMPTY (is_valid=0) without these — halbb_ic_hw_setting_init_8852c sets the
+   * BB evm/measurement report-enable (0xa10[0]), and the physts CR map + IE
+   * bitmap must be programmed for the engine to snapshot RSSI/SNR/EVM. */
+#ifdef BB_8852C_SUPPORT
+  if (bb->ic_type == BB_RTL8852C) {
+    halbb_ic_hw_setting_init_8852c(bb); /* 0xa10[0] evm/measurement rpt-en */
+    halbb_cr_cfg_physts_init(bb);
+    halbb_physts_parsing_init(bb);
+  }
+#endif
 }
 
 void kestrel_halbb_set_gain(struct kestrel_halbb_ctx *ctx, unsigned char central_ch,

src/kestrel/HalKestrel.cpp

@@ -1920,18 +1920,26 @@ void HalKestrel::bb_reset_all() {
   bb_rmw(0x3200, 0x7u << 28, 0x0);
   bb_rmw(0x704, 1u << 1, 1);
   if (_variant == ChipVariant::C8852C) {
-    /* cfg_phy_rpt (phy_rpt.c) for the 8852C, matching the working vendor
-     * driver's R_AX_PPDU_STAT (0xCE40) = 0x0B00020F: RPT_EN(0) | APP_MAC_INFO(1)
-     * | APP_RX_CNT(2) | APP_PLCP_HDR(3) | DMA_MODE(9, the is_chip_id(8852C)
-     * bit) | the PPDU filter HAS_A1M/CRC_OK/DMA_OK (24/25/27). Devourer's
-     * byte-OR only sets RPT_EN; without the filter bits no PPDU gets a status
-     * report, so the 8852C emits zero physts (rate/RSSI read 0). Also forward
-     * PPDU-status to the host, not the WLCPU (R_AX_HW_RPT_FWD 0x9C18[1:0]=1). */
+    /* cfg_phy_rpt (phy_rpt.c) for the 8852C R_AX_PPDU_STAT (0xCE40) =
+     * 0x0B000201: RPT_EN(0) | DMA_MODE(9, the is_chip_id(8852C) bit) | the PPDU
+     * report filter HAS_A1M/CRC_OK/DMA_OK (24/25/27). Devourer's byte-OR only
+     * sets RPT_EN; without the filter bits no PPDU gets a status report, so the
+     * 8852C emits zero physts.
+     *   NB the vendor's value ALSO sets APP_MAC_INFO(1)/APP_RX_CNT(2)/
+     * APP_PLCP_HDR(3), which PREPEND those blocks to the report and push the
+     * physts_hdr_info out of place (devourer parses the physts, not the appended
+     * MAC info) — with them set, the report reads as an invalid/empty physts
+     * (is_valid=0). Clearing them makes the report the bare physts, bit-identical
+     * to the 8852B (is_valid + rssi_avg_td + IE_01), which the RPKT_TYPE_PPDU
+     * handler + the halbb measurement bring-up (kestrel_halbb_rx_bringup 8852C
+     * branch) turn into a working per-frame RSSI/SNR passive floor.
+     * Also forward PPDU-status to the host, not the WLCPU (R_AX_HW_RPT_FWD
+     * 0x9C18[1:0]=1). */
     const uint32_t pre = _device.rtw_read32(0xce40);
-    _device.rtw_write32(0xce40, 0x0B00020Fu);
+    _device.rtw_write32(0xce40, 0x0B000201u);
     _device.rtw_write32(0x9C18,
                         (_device.rtw_read32(0x9C18) & ~0x3u) | 0x1u);
-    _logger->info("Kestrel PPDU_STAT(8852C): 0xCE40 0x{:08x} -> 0x0B00020F", pre);
+    _logger->info("Kestrel PPDU_STAT(8852C): 0xCE40 0x{:08x} -> 0x0B000201", pre);
   } else {
     v = _device.rtw_read8(0xce40); /* start phy-sts update */
     _device.rtw_write8(0xce40, static_cast<uint8_t>(v | 0x1));

src/kestrel/RtlKestrelDevice.cpp

@@ -298,11 +298,11 @@ void RtlKestrelDevice::StartRxLoop(Action_ParsedRadioPacket packetProcessor) {
              * (byte0 [4:0] == 1) before trusting the offset: avg_snr is IE byte 8
              * [5:0] in dB. Store as raw = dB*2 (the RxQualityAccumulator
              * convention snr_db = raw/2). 0 when IE_01 absent (e.g. CCK).
-             * On-air-validated on the C8852B (passive floor cross-matches the NHM
-             * floor within ~1 dB). The C8852C physts layout differs (16-byte
-             * drv_info); IE_01 is not at this offset there, so snr stays 0 and the
-             * passive floor is null on the C — a follow-up (RSSI/LinkHealth still
-             * populate). */
+             * On-air-validated on BOTH dies (passive floor cross-matches the
+             * NHM floor within ~1 dB): the C8852C physts is bit-identical to the
+             * C8852B once its measurement engine is brought up (the 8852C branch
+             * in kestrel_halbb_rx_bringup + the R_AX_PPDU_STAT no-APP-prepend
+             * config in bb_reset_all) — same header, same IE_01 offset. */
             _last_snr = 0;
             if (f.payload_len >= 8 + 9 && (f.payload[8] & 0x1f) == 1)
               _last_snr = static_cast<uint8_t>((f.payload[16] & 0x3f) * 2);
@@ -372,10 +372,15 @@ RxEnergy RtlKestrelDevice::GetRxEnergy() {
    * env-monitor. Frame-free, BB-driven, no clock-stop -> no wedge.
    * ~mntr_time (100 ms) of control-thread wait; opt-in. Guard to a plausible
    * idle-floor band so a not-ready/garbage report never emits a fake dBm.
-   * C8852B only: the NHM triggers on the C8852C but its nhm_pwr reads ~25 dB
-   * high (an 8852C-specific scaling/reference not yet resolved — on-air, idle
-   * ch149 reads -68 dBm vs the 8852B's -93), so it stays null on the C rather
-   * than emit a wrong value. 8852C is a follow-up. */
+   * C8852B only: the NHM triggers on the C8852C but its nhm_pwr reads ~23 dB
+   * high (on-air ch36 the NHM reads -70 dBm while the passive floor and the
+   * 8852B NHM both read -93). The offset is in the NHM's raw HW gain reference,
+   * not the SW path (halbb_env_mntr treats the 8852C identically to the 8852B)
+   * and not the front-end gain (the physts RSSI is correct — the passive floor
+   * cross-matches the 8852B NHM within ~1 dB). The vendor has no 8852C NHM
+   * offset; it is a deeper RF-cal reference. The C8852C's absolute floor is met
+   * by the passive rssi-snr floor (GetRxQuality), so the frame-free NHM stays
+   * 8852B-only rather than emit the wrong -70. */
   if (_cfg.rx.abs_noise_floor && _variant == kestrel::ChipVariant::C8852B) {
     int8_t nf = 0;
     if (_hal.nhm_noise_floor(nf) && nf <= -60 && nf >= -105) {

tests/kestrel_physts_floor_onair.sh

@@ -0,0 +1,90 @@
+#!/usr/bin/env bash
+# On-air validation for the Kestrel passive noise floor (RtlKestrelDevice PPDU
+# handler -> rssi-snr -> RxQualityAccumulator) on BOTH dies.
+#
+# The gap this closes: the C8852C emitted EMPTY physts reports
+# (is_valid=0, all-zero content) so it had no per-frame RSSI/SNR and a NULL
+# passive floor. Root cause was the 8852C physts MEASUREMENT bring-up, not the
+# parse: (a) halbb_ic_hw_setting_init_8852c sets the BB evm/measurement
+# report-enable (0xa10[0]); (b) the physts CR map + IE bitmap must be programmed
+# (halbb_cr_cfg_physts_init + halbb_physts_parsing_init); (c) R_AX_PPDU_STAT
+# (0xCE40) must NOT set the APP_MAC_INFO/RX_CNT/PLCP_HDR prepend bits (1/2/3),
+# which pushed the physts_hdr_info out of place. With those, the 8852C physts is
+# bit-identical to the 8852B (byte0 is_valid, byte3 rssi_avg_td, IE_01 avg_snr),
+# so the existing hand-parse works for both dies.
+#
+# CHECK: with DEVOURER_RXQUALITY on an ambient channel, the passive
+# noise_floor_dbm populates (non-null, plausible -80..-100 band) on BOTH dies,
+# and the C8852B is unchanged from before.
+#
+# Usage: sudo -v && tests/kestrel_physts_floor_onair.sh
+set -u
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+OUT="${KPFOUT:-/tmp/devourer-kestrel-physts}"
+CH="${CH:-6}"        # ambient-traffic channel (2.4 GHz; both dies do monitor RX)
+DUR="${DUR:-8}"
+mkdir -p "$OUT"
+
+VID=0x35bc
+C_PID=0x0101         # RTL8832CU / C8852C  (the die the fix targets)
+B_PID=0x0108         # RTL8852BU / C8852B  (regression control)
+
+plugged() { lsusb -d "$(printf '%04x:%04x' "$1" "$2")" >/dev/null 2>&1; }
+unbind() { local pid="$1" d p i
+  for d in /sys/bus/usb/devices/*/idProduct; do p=$(cat "$d" 2>/dev/null) || continue
+    [ "$p" = "${pid#0x}" ] || continue
+    for i in "$(dirname "$d")":*; do
+      [ -e "$i/driver" ] && sudo sh -c "echo '$(basename "$i")' > '$i/driver/unbind'" 2>/dev/null || true
+    done; done; }
+
+run_die() { # $1=pid $2=tag -> "n snr passiveNF activeNF rssiMax"
+  sudo env DEVOURER_VID="$VID" DEVOURER_PID="$1" DEVOURER_CHANNEL="$CH" \
+    DEVOURER_RXQUALITY=1 DEVOURER_RX_NOISE_FLOOR=1 DEVOURER_RX_ENERGY_MS=500 \
+    timeout "$DUR" "$ROOT/build/rxdemo" >"$OUT/$2.log" 2>/dev/null || true
+  grep '"ev":"rx.quality"' "$OUT/$2.log" 2>/dev/null | python3 "$OUT/med.py"
+}
+
+cat >"$OUT/med.py" <<'PYEOF'
+import json,sys,statistics as st
+rows=[json.loads(l) for l in sys.stdin]
+def med(k):
+    v=[x[k] for x in rows if isinstance(x.get(k),(int,float))]
+    return round(st.median(v),1) if v else None
+def s(x): return "null" if x is None else str(x)
+print("\t".join([str(len(rows)), s(med("snr_mean_db")), s(med("noise_floor_dbm")),
+                 s(med("abs_noise_floor_dbm")), s(med("rssi_max_dbm"))]))
+PYEOF
+
+echo "== building rxdemo =="; cmake --build "$ROOT/build" -j --target rxdemo >/dev/null || exit 1
+printf "\n%-8s %-7s %-8s %-11s %-10s %-9s\n" DIE qual_ev snr_dB passiveNF activeNF rssiMax
+: >"$OUT/summary.tsv"
+for spec in "C8852C:$C_PID" "C8852B:$B_PID"; do
+  name="${spec%%:*}"; pid="${spec##*:}"
+  plugged "$VID" "$pid" || { printf "%-8s SKIP (not plugged)\n" "$name"; continue; }
+  unbind "$pid"
+  read -r n snr nf anf rmax < <(run_die "$pid" "$name")
+  printf "%-8s %-7s %-8s %-11s %-10s %-9s\n" "$name" "${n:-0}" "${snr:-null}" "${nf:-null}" "${anf:-null}" "${rmax:-null}"
+  printf "%s\t%s\t%s\t%s\t%s\t%s\n" "$name" "${n:-0}" "${snr:-null}" "${nf:-null}" "${anf:-null}" "${rmax:-null}" >>"$OUT/summary.tsv"
+done
+
+echo
+python3 - "$OUT/summary.tsv" <<'PYEOF'
+import sys
+def num(x):
+    try: return float(x)
+    except: return None
+rows={}
+for l in open(sys.argv[1]):
+    f=l.rstrip("\n").split("\t"); rows[f[0]]=f
+for name in ("C8852C","C8852B"):
+    r=rows.get(name)
+    if not r: print(f"  {name}: no data"); continue
+    nf=num(r[3])
+    if nf is None: print(f"  {name}: passive floor NULL (FAIL)")
+    elif -100<=nf<=-80: print(f"  {name}: passive floor {nf:.0f} dBm, snr {r[2]} dB -> PASS")
+    else: print(f"  {name}: passive floor {nf} dBm (snr {r[2]}) -> INSPECT")
+c,b=rows.get("C8852C"),rows.get("C8852B")
+if c and b and num(c[3]) is not None and num(b[3]) is not None:
+    print(f"  cross-die delta {abs(num(c[3])-num(b[3])):.0f} dB")
+print(f"\n  raw: {sys.argv[1]}")
+PYEOF