Add guarded nRF SPI startup diagnostic for private 16 MHz trials

src/helpers/radiolib/NrfRadioSpiStartupDiagHal.cpp

@@ -0,0 +1,12 @@
+#include "NrfRadioSpiStartupDiagHal.h"
+
+#if MESH_HIL_SPI_STARTUP_DIAG
+namespace mesh { namespace spistartup {
+extern "C" {
+volatile Capture mesh_hil_spi_startup = {
+    0x4d435353, 1, sizeof(Capture), Idle,
+    0, UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX,
+    0, 0, 0, UINT32_MAX, 0};
+}
+} }
+#endif

src/helpers/radiolib/NrfRadioSpiStartupDiagHal.h

@@ -0,0 +1,77 @@
+#pragma once
+
+#ifndef MESH_HIL_SPI_STARTUP_DIAG
+#define MESH_HIL_SPI_STARTUP_DIAG 0
+#endif
+#if MESH_HIL_SPI_STARTUP_DIAG != 0 && MESH_HIL_SPI_STARTUP_DIAG != 1
+#error "SPI startup diagnostic flag must be 0 or 1"
+#endif
+
+#if MESH_HIL_SPI_STARTUP_DIAG
+#if !defined(NRF52_PLATFORM)
+#error "SPI startup diagnostic requires nRF52"
+#endif
+
+#include "Nrf52BufferedRadioHal.h"
+#include <helpers/nrf52/SoftDeviceState.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+namespace mesh { namespace spistartup {
+
+enum Phase : uint32_t { Idle = 0, Query = 1, Transfer = 2, Completed = 3, Refused = 4 };
+
+// Fixed 14-word ABI for private SWD reads, including before USB is usable.
+// Each word is independently observable; this is not an atomic snapshot.
+struct Capture {
+  uint32_t magic, version, size_bytes, phase;
+  uint32_t queries, first_query_result, first_query_enabled;
+  uint32_t last_query_result, last_query_enabled;
+  uint32_t begun, completed, refused, last_opcode, last_length;
+};
+static_assert(sizeof(Capture) == 56 && offsetof(Capture, begun) == 36
+              && offsetof(Capture, last_length) == 52, "SPI startup capture ABI changed");
+extern "C" {
+extern volatile Capture mesh_hil_spi_startup;
+}
+
+} } // namespace mesh::spistartup
+
+// Diagnostic only: the global nrfx anomaly-198 workaround cannot coexist
+// with SoftDevice. Refuse the actual frame unless its disabled state was
+// positively established by the existing LTO-safe supervisor query.
+class NrfRadioSpiStartupDiagHal : public Nrf52BufferedRadioHal {
+public:
+  explicit NrfRadioSpiStartupDiagHal(SPIClass& bus, uint32_t hz)
+      : Nrf52BufferedRadioHal(bus, hz) {}
+
+  void spiTransfer(uint8_t* out, size_t len, uint8_t* in) override {
+    if (!len) return;
+    auto& capture = mesh::spistartup::mesh_hil_spi_startup;
+    capture.last_opcode = out ? out[0] : UINT32_MAX;
+    capture.last_length = static_cast<uint32_t>(len);
+    capture.phase = mesh::spistartup::Query;
+    uint8_t enabled = 0;
+    const uint32_t result = mesh_nrf52::softdeviceIsEnabled(enabled);
+    if (!capture.queries) {
+      capture.first_query_result = result;
+      capture.first_query_enabled = enabled;
+    }
+    ++capture.queries;
+    capture.last_query_result = result;
+    capture.last_query_enabled = enabled;
+    if (result != 0 || enabled != 0) {
+      if (in) memset(in, 0x2a, len); // SX126x command-failed status.
+      ++capture.refused;
+      capture.phase = mesh::spistartup::Refused;
+      return;
+    }
+    ++capture.begun;
+    capture.phase = mesh::spistartup::Transfer;
+    Nrf52BufferedRadioHal::spiTransfer(out, len, in);
+    ++capture.completed;
+    capture.phase = mesh::spistartup::Completed;
+  }
+};
+#endif