Add frdm-mcxw71 support

tutorials/nxp/frdm-mcxw71/minimal/hal.c

@@ -2,6 +2,61 @@
 // All rights reserved
 
 #include "hal.h"
+#include "mongoose.h"
+
+// Initialise the transceiver the way NXP XCVR_Init() does it: start the RF
+// oscillator, wait for the radio to wake up, enable its clocks and load the
+// 802.15.4 register setup. Then select the legacy 802.15.4 demodulator and
+// CCA from RX digital. See PhyHwInit() in NXP ieee_802_15_4 PHY sources,
+// PhyPacketProcessor.c
+bool hal_radio_init(void) {
+  uint32_t stat = RFMC_RF2P4GHZ_STAT_RST_STAT_MASK |
+                  RFMC_RF2P4GHZ_STAT_LP_ACK_STAT_MASK;
+  size_t i, n = 1000000;
+  RFMC->CTRL &= ~RFMC_CTRL_RFMC_RST_MASK;                // RFMC out of reset
+  RFMC->RF2P4GHZ_CTRL |= RFMC_RF2P4GHZ_CTRL_XO_EN_MASK;  // Start RF oscillator
+  RFMC->RF2P4GHZ_CTRL &=
+      ~(RFMC_RF2P4GHZ_CTRL_LP_ENTER_MASK | RFMC_RF2P4GHZ_CTRL_RF_POR_MASK |
+        RFMC_RF2P4GHZ_CTRL_RST_MASK);  // Release radio reset, no low power
+  while ((RFMC->RF2P4GHZ_STAT & stat) != 0 ||
+         (RFMC->XO_STAT & RFMC_XO_STAT_XTAL_RDY_MASK) == 0) {
+    if (--n == 0) return false;  // Radio did not wake up
+  }
+  RADIO_CTRL->LL_CTRL = RADIO_CTRL_LL_CTRL_ACTIVE_LL_MASK;
+  RFMC->RF2P4GHZ_CTRL |=
+      RFMC_RF2P4GHZ_CTRL_BLE_LP_EN_MASK | RFMC_RF2P4GHZ_CTRL_BLE_WKUP_MASK;
+  for (i = 0; i < sizeof(s_radio_regs) / sizeof(s_radio_regs[0]); i++) {
+    *s_radio_regs[i].reg = s_radio_regs[i].val;
+  }
+  XCVR_MISC->XCVR_CTRL &= ~XCVR_MISC_XCVR_CTRL_DEMOD_SEL_MASK;
+  XCVR_MISC->XCVR_CTRL |= XCVR_MISC_XCVR_CTRL_DEMOD_SEL(2);
+  XCVR_ZBDEMOD->CCA_LQI_SRC |= XCVR_ZBDEMOD_CCA_LQI_SRC_CCA1_FROM_RX_DIG(1);
+  return true;
+}
+
+// Random bytes for Mongoose, MG_ENABLE_CUSTOM_RANDOM. Entropy is radio noise:
+// receiver RSSI, sampled while the radio receives, mixed with SysTick by
+// SHA-256. Good enough for random addresses and nonces, not a certified TRNG
+bool mg_random(void *buf, size_t len) {
+  static uint32_t counter;
+  uint8_t digest[32], *p = (uint8_t *) buf;
+  size_t i, n;
+  while (len > 0) {
+    mg_sha256_ctx ctx;
+    mg_sha256_init(&ctx);
+    counter++;
+    mg_sha256_update(&ctx, (uint8_t *) &counter, sizeof(counter));
+    for (i = 0; i < 64; i++) {
+      uint32_t sample[2] = {XCVR_RX_DIG->NB_RSSI_RES0, SysTick->VAL};
+      mg_sha256_update(&ctx, (uint8_t *) sample, sizeof(sample));
+      for (n = 0; n < 50; n++) __NOP();  // Let the RSSI update
+    }
+    mg_sha256_final(digest, &ctx);
+    n = len < sizeof(digest) ? len : sizeof(digest);
+    memcpy(p, digest, n), p += n, len -= n;
+  }
+  return true;
+}
 
 // Added to minimise the bin size: avoid pulling printf and friends
 void __assert_func(const char *s, int line, const char *fn, const char *expr) {