ieee802154/submac: implement MR-FSK timings

sys/include/net/ieee802154.h

@@ -125,6 +125,13 @@ extern "C" {
  */
 #define IEEE802154_MR_OFDM_SYMBOL_TIME_US   (120)
 
+/**
+ * @brief Symbol time for IEEE 802.15.4 MR-FSK in µs
+ *
+ * symbol time is always 20 µs for MR-FSK (table 0, pg. 7)
+ */
+#define IEEE802154_MR_FSK_SYMBOL_TIME_US    (20)
+
 /**
  * @brief value of measured power when RSSI is zero.
  *
@@ -190,11 +197,23 @@ typedef enum {
 /**
  * @brief   802.15.4 forward error correction schemes
  */
-enum {
+typedef enum {
     IEEE802154_FEC_NONE,            /**< no forward error correction */
     IEEE802154_FEC_NRNSC,           /**< non-recursive and non-systematic code */
     IEEE802154_FEC_RSC              /**< recursive and systematic code */
-};
+} ieee802154_mr_fsk_fec_t;
+
+/**
+ * @brief   802.15.4 MR-FSK symbol rates
+ */
+typedef enum {
+    IEEE802154_MR_FSK_SRATE_50K,    /**< 50k Symbols/s  */
+    IEEE802154_MR_FSK_SRATE_100K,   /**< 100k Symbols/s */
+    IEEE802154_MR_FSK_SRATE_150K,   /**< 150k Symbols/s */
+    IEEE802154_MR_FSK_SRATE_200K,   /**< 200k Symbols/s */
+    IEEE802154_MR_FSK_SRATE_300K,   /**< 300k Symbols/s */
+    IEEE802154_MR_FSK_SRATE_400K,   /**< 400k Symbols/s */
+} ieee802154_mr_fsk_srate_t;
 
 /**
  * @brief   802.15.4 MR-OQPSK chip rates
@@ -206,6 +225,32 @@ typedef enum {
     IEEE802154_MR_OQPSK_CHIPS_2000, /**< 2000 kChip/s */
 } ieee802154_mr_oqpsk_chips_t;
 
+/**
+ * @brief Get the minimum pramble length for a given symbol rate
+ *
+ * From IEEE 802.15.4g Table 6-64
+ *
+ * @param[in] srate     symbol rate
+ * @return    preamble length in bytes
+ */
+static inline uint8_t ieee802154_mr_fsk_plen(ieee802154_mr_fsk_srate_t srate)
+{
+    switch (srate) {
+    case IEEE802154_MR_FSK_SRATE_50K:
+        return 2;
+    case IEEE802154_MR_FSK_SRATE_100K:
+        return 3;
+    case IEEE802154_MR_FSK_SRATE_150K:
+    case IEEE802154_MR_FSK_SRATE_200K:
+    case IEEE802154_MR_FSK_SRATE_300K:
+        return 8;
+    case IEEE802154_MR_FSK_SRATE_400K:
+        return 10;
+    }
+
+    return 0;
+}
+
 /**
  * @brief   Special address definitions
  * @{
@@ -302,6 +347,34 @@ extern const uint8_t ieee802154_addr_bcast[IEEE802154_ADDR_BCAST_LEN];
 #define CONFIG_IEEE802154_MR_OFDM_DEFAULT_SCHEME    (2U)
 #endif
 
+/**
+ * @brief IEEE802.15.4 MR-FSK default symbol rate
+ */
+#ifndef CONFIG_IEEE802154_MR_FSK_DEFAULT_SRATE
+#define CONFIG_IEEE802154_MR_FSK_DEFAULT_SRATE      IEEE802154_MR_FSK_SRATE_200K
+#endif
+
+/**
+ * @brief IEEE802.15.4 MR-FSK default modulation index, fraction of 64
+ */
+#ifndef CONFIG_IEEE802154_MR_FSK_DEFAULT_MOD_IDX
+#define CONFIG_IEEE802154_MR_FSK_DEFAULT_MOD_IDX    (64U)
+#endif
+
+/**
+ * @brief IEEE802.15.4 MR-FSK default modulation order
+ */
+#ifndef CONFIG_IEEE802154_MR_FSK_DEFAULT_MOD_ORD
+#define CONFIG_IEEE802154_MR_FSK_DEFAULT_MOD_ORD    (2U)
+#endif
+
+/**
+ * @brief IEEE802.15.4 MR-FSK default error correction mode
+ */
+#ifndef CONFIG_IEEE802154_MR_FSK_DEFAULT_FEC
+#define CONFIG_IEEE802154_MR_FSK_DEFAULT_FEC        IEEE802154_FEC_NONE
+#endif
+
 /**
  * @brief IEEE802.15.4 default PANID
  */

sys/include/net/ieee802154/radio.h

@@ -477,6 +477,17 @@ typedef struct {
     uint8_t scheme;                     /**< Modulation & Coding Scheme */
 } ieee802154_mr_odmf_conf_t;
 
+/**
+ * @brief extension for IEEE 802.15.4g MR-FSK PHY
+ */
+typedef struct {
+    ieee802154_phy_conf_t super;        /**< common settings */
+    ieee802154_mr_fsk_srate_t srate;    /**< symbol rate */
+    uint8_t mod_ord;                    /**< modulation order, 2 or 4 */
+    uint8_t mod_idx;                    /**< modulation index */
+    ieee802154_mr_fsk_fec_t fec;        /**< forward error correction */
+} ieee802154_mr_fsk_conf_t;
+
 /**
  * @brief IEEE 802.15.4 radio operations
  */

sys/net/link_layer/ieee802154/submac.c

@@ -498,6 +498,7 @@ static inline uint8_t _mr_oqpsk_ack_psdu_duration_syms(uint8_t chips, uint8_t mo
     return (Npsdu + Ns/2) / Ns + (Npsdu + 8 * Ns) / (16 * Ns);
 }
 
+MAYBE_UNUSED
 static inline uint16_t _mr_oqpsk_ack_timeout_us(const ieee802154_mr_oqpks_conf_t *conf)
 {
     /* see 802.15.4g-2012, p. 30 */
@@ -510,6 +511,7 @@ static inline uint16_t _mr_oqpsk_ack_timeout_us(const ieee802154_mr_oqpks_conf_t
          + IEEE802154G_ATURNAROUNDTIME_US;
 }
 
+MAYBE_UNUSED
 static inline uint16_t _mr_oqpsk_csma_backoff_period_us(const ieee802154_mr_oqpks_conf_t *conf)
 {
     return _mr_oqpsk_cca_duration_syms(conf->chips) * _mr_oqpsk_symbol_duration_us(conf->chips)
@@ -546,6 +548,7 @@ static inline uint16_t _mr_ofdm_csma_backoff_period_us(const ieee802154_mr_odmf_
          + IEEE802154G_ATURNAROUNDTIME_US;
 }
 
+MAYBE_UNUSED
 static inline uint16_t _mr_ofdm_ack_timeout_us(const ieee802154_mr_odmf_conf_t *conf)
 {
     return _mr_ofdm_csma_backoff_period_us(conf)
@@ -553,6 +556,47 @@ static inline uint16_t _mr_ofdm_ack_timeout_us(const ieee802154_mr_odmf_conf_t *
          + _mr_ofdm_frame_duration(conf->option, conf->scheme, IEEE802154_ACK_FRAME_LEN);
 }
 
+/*
+ * MR-FSK timing calculations
+ *
+ * The standard unfortunately does not list the formula, instead it has to be pieced together
+ * from scattered information and tables in the IEEE 802.15.4 document - may contain errors.
+ */
+
+MAYBE_UNUSED
+static inline uint16_t _mr_fsk_csma_backoff_period_us(const ieee802154_mr_fsk_conf_t *conf)
+{
+    (void)conf;
+
+    return IEEE802154_CCA_DURATION_IN_SYMBOLS * IEEE802154_MR_FSK_SYMBOL_TIME_US
+         + IEEE802154G_ATURNAROUNDTIME_US;
+}
+
+MAYBE_UNUSED
+static inline uint16_t _mr_fsk_ack_timeout_us(const ieee802154_mr_fsk_conf_t *conf)
+{
+    uint8_t ack_len = IEEE802154_ACK_FRAME_LEN;
+    uint8_t fsk_pl = ieee802154_mr_fsk_plen(conf->srate);
+
+    /* PHR uses same data rate as PSDU */
+    ack_len += 2;
+
+    /* 4-FSK doubles data rate */
+    if (conf->mod_ord == 4) {
+        ack_len /= 2;
+    }
+
+    /* forward error correction halves data rate */
+    if (conf->fec) {
+        ack_len *= 2;
+    }
+
+    return _mr_fsk_csma_backoff_period_us(conf)
+         + IEEE802154G_ATURNAROUNDTIME_US
+         /* long Preamble + SFD; SFD=2 */
+         + ((fsk_pl * 8 + 2) + ack_len) * 8 * IEEE802154_MR_FSK_SYMBOL_TIME_US;
+}
+
 static int ieee802154_submac_config_phy(ieee802154_submac_t *submac,
                                         const ieee802154_phy_conf_t *conf)
 {
@@ -572,6 +616,12 @@ static int ieee802154_submac_config_phy(ieee802154_submac_t *submac,
         submac->ack_timeout_us = _mr_ofdm_ack_timeout_us((void *)conf);
         submac->csma_backoff_us = _mr_ofdm_csma_backoff_period_us((void *)conf);
         break;
+#endif
+#ifdef MODULE_NETDEV_IEEE802154_MR_FSK
+    case IEEE802154_PHY_MR_FSK:
+        submac->ack_timeout_us = _mr_fsk_ack_timeout_us((void *)conf);
+        submac->csma_backoff_us = _mr_fsk_csma_backoff_period_us((void *)conf);
+        break;
 #endif
     case IEEE802154_PHY_NO_OP:
     case IEEE802154_PHY_DISABLED:
@@ -658,6 +708,9 @@ int ieee802154_submac_init(ieee802154_submac_t *submac, const network_uint16_t *
 #endif
 #ifdef MODULE_NETDEV_IEEE802154_MR_OFDM
         ieee802154_mr_odmf_conf_t mr_ofdm;
+#endif
+#ifdef MODULE_NETDEV_IEEE802154_MR_FSK
+        ieee802154_mr_fsk_conf_t mr_fsk;
 #endif
     } conf;
 
@@ -673,6 +726,14 @@ int ieee802154_submac_init(ieee802154_submac_t *submac, const network_uint16_t *
         conf.mr_ofdm.scheme = CONFIG_IEEE802154_MR_OFDM_DEFAULT_SCHEME;
     }
 #endif
+#ifdef MODULE_NETDEV_IEEE802154_MR_FSK
+    if (submac->phy_mode == IEEE802154_PHY_MR_FSK) {
+        conf.mr_fsk.srate = CONFIG_IEEE802154_MR_FSK_DEFAULT_SRATE;
+        conf.mr_fsk.mod_ord = CONFIG_IEEE802154_MR_FSK_DEFAULT_MOD_ORD;
+        conf.mr_fsk.mod_idx = CONFIG_IEEE802154_MR_FSK_DEFAULT_MOD_IDX;
+        conf.mr_fsk.fec = CONFIG_IEEE802154_MR_FSK_DEFAULT_FEC;
+    }
+#endif
 
     conf.super.phy_mode = submac->phy_mode;
     conf.super.channel = submac->channel_num;