nimble/ll: Add CS_SYNC transmission/reception

- CS SYNC sequence generation
- CS Access Address matching

Author: mkasenberg

nimble/controller/src/ble_ll_cs.c

@@ -31,7 +31,7 @@
 #include "ble_ll_cs_priv.h"
 
 struct ble_ll_cs_supp_cap g_ble_ll_cs_local_cap;
-static struct ble_ll_cs_sm g_ble_ll_cs_sm[MYNEWT_VAL(BLE_MAX_CONNECTIONS)];
+struct ble_ll_cs_sm g_ble_ll_cs_sm[MYNEWT_VAL(BLE_MAX_CONNECTIONS)];
 static const uint8_t t_ip1[] = {10, 20, 30, 40, 50, 60, 80, 145};
 static const uint8_t t_ip2[] = {10, 20, 30, 40, 50, 60, 80, 145};
 static const uint8_t t_fcs[] = {15, 20, 30, 40, 50, 60, 80, 100, 120, 150};

nimble/controller/src/ble_ll_cs_sync.c

@@ -21,11 +21,67 @@
 #if MYNEWT_VAL(BLE_LL_CHANNEL_SOUNDING)
 #include <stdint.h>
 #include "controller/ble_ll.h"
+#include "controller/ble_ll_conn.h"
 #include "controller/ble_ll_sched.h"
 #include "controller/ble_ll_tmr.h"
+#include "controller/ble_hw.h"
+#include "controller/ble_ll_hci.h"
+#include "mbedtls/aes.h"
+#include "ble_ll_priv.h"
 #include "ble_ll_cs_priv.h"
 
+extern struct ble_ll_cs_sm g_ble_ll_cs_sm[MYNEWT_VAL(BLE_MAX_CONNECTIONS)];
 extern struct ble_ll_cs_sm *g_ble_ll_cs_sm_current;
+extern int8_t g_ble_ll_tx_power;
+
+static uint8_t
+ble_ll_cs_sync_make(struct ble_ll_cs_sm *cssm, uint8_t *buf)
+{
+    int i;
+    int rc;
+    uint32_t aa;
+    struct ble_ll_cs_config *conf = cssm->active_config;
+    uint8_t sequence_len;
+    uint8_t bits;
+
+    if (conf->rtt_type != BLE_LL_CS_RTT_AA_ONLY) {
+        rc = ble_ll_cs_drbg_generate_sync_sequence(
+            &cssm->drbg_ctx, cssm->steps_in_procedure_count, conf->rtt_type,
+            buf, &sequence_len);
+
+        if (rc) {
+            return 0;
+        }
+    }
+
+    /* Shift by 4 bits to make space for trailer bits */
+    if (sequence_len > 0) {
+        assert(sequence_len >= BLE_PHY_MAX_PDU_LEN);
+        buf[sequence_len] = 0;
+        bits = 0;
+        for (i = sequence_len - 1; i >= 0; --i) {
+            bits = buf[i] >> 4;
+            buf[i] = (buf[i] << 4) & 0xF0;
+            buf[i + 1] = (buf[i + 1] & 0xF0) | bits;
+        }
+    }
+
+    if (conf->role == BLE_LL_CS_ROLE_INITIATOR) {
+        aa = cssm->initiator_aa;
+    } else {
+        aa = cssm->reflector_aa;
+    }
+
+    /* Set the trailer bits */
+    if (aa & 0x80000000) {
+        buf[0] |= 0x0A;
+    } else {
+        buf[0] |= 0x05;
+    }
+    ++sequence_len;
+
+    return sequence_len;
+}
 
 /**
  * Called when a CS pkt has been transmitted.
@@ -43,22 +99,114 @@ ble_ll_cs_sync_tx_end_cb(void *arg)
     ble_ll_cs_proc_schedule_next_tx_or_rx(cssm);
 }
 
+static uint8_t
+ble_ll_cs_sync_tx_make(uint8_t *dptr, void *arg, uint8_t *hdr_byte)
+{
+    uint8_t pdu_len;
+    struct ble_ll_cs_sm *cssm = arg;
+
+    /* TODO: Unused fields in CS Sync packet */
+    pdu_len = ble_ll_cs_sync_make(cssm, dptr);
+    *hdr_byte = 0;
+
+    return pdu_len;
+}
+
 int
 ble_ll_cs_sync_tx_sched_cb(struct ble_ll_sched_item *sch)
 {
-    /* TODO: Start TX of CS SYNC */
+    int rc;
+    struct ble_ll_cs_sm *cssm = sch->cb_arg;
+
+    BLE_LL_ASSERT(ble_ll_state_get() == BLE_LL_STATE_STANDBY);
+
+    /* TODO: Add to PHY a support CS mode.
+     * Adjustments for nrf:
+     * - Turn off CRC
+     * - set 4 bits in S1
+     *
+     * ble_ll_phy_to_cs_sync_mode(cssm->active_config->cs_sync_phy, 0);
+     */
+
+    ble_ll_tx_power_set(g_ble_ll_tx_power);
+
+    rc = ble_phy_tx_set_start_time(sch->start_time + g_ble_ll_sched_offset_ticks,
+                                   sch->remainder);
+    if (rc) {
+        return BLE_LL_SCHED_STATE_DONE;
+    }
+
+    ble_phy_set_txend_cb(ble_ll_cs_sync_tx_end_cb, cssm);
+
+    /* TODO: Add to PHY a support for 72 RF channels for CS exchanges.
+     * ble_phy_cs_setchan(cssm->channel, cssm->tx_aa, 0);
+     */
+
+    /* TODO: Add to PHY a support for CS_SYNC transmission.
+     * rc = ble_phy_tx_cs_sync(ble_ll_cs_sync_tx_make, cssm,
+     *                         BLE_PHY_TRANSITION_TX_RX);
+     */
+    (void) ble_ll_cs_sync_tx_make;
+    if (rc) {
+        ble_phy_disable();
+        return BLE_LL_SCHED_STATE_DONE;
+    }
+
+    ble_ll_state_set(BLE_LL_STATE_CS);
 
     return BLE_LL_SCHED_STATE_RUNNING;
 }
 
 int
 ble_ll_cs_sync_rx_sched_cb(struct ble_ll_sched_item *sch)
 {
-    /* TODO: Start RX of CS SYNC */
+    int rc;
+    uint32_t wfr_usecs;
+    struct ble_ll_cs_sm *cssm = sch->cb_arg;
+
+    BLE_LL_ASSERT(ble_ll_state_get() == BLE_LL_STATE_STANDBY);
+
+    /* TODO: Add to PHY a support CS mode.
+     * Adjustments for nrf:
+     * - Turn off CRC
+     * - set 4 bits in S1
+     *
+     * ble_ll_phy_to_cs_sync_mode(cssm->active_config->cs_sync_phy, 0);
+     */
+
+    /* TODO: Add to PHY a support for 72 RF channels for CS exchanges.
+     * ble_phy_cs_setchan(cssm->channel, cssm->tx_aa, 0);
+     */
+
+    rc = ble_phy_rx_set_start_time(sch->start_time + g_ble_ll_sched_offset_ticks,
+                                   sch->remainder);
+    if (rc) {
+        return BLE_LL_SCHED_STATE_DONE;
+    }
+
+    wfr_usecs = cssm->duration_usecs;
+    ble_phy_wfr_enable(BLE_PHY_WFR_ENABLE_RX, 0, wfr_usecs);
 
     return BLE_LL_SCHED_STATE_RUNNING;
 }
 
+static struct ble_ll_cs_sm *
+ble_ll_cs_sync_find_sm_match_aa(uint32_t aa)
+{
+    int i;
+    struct ble_ll_cs_sm *cssm;
+
+    for (i = 0; i < ARRAY_SIZE(g_ble_ll_cs_sm); ++i) {
+        cssm = &g_ble_ll_cs_sm[i];
+
+        if (cssm->rx_aa == aa) {
+            return cssm;
+        }
+    }
+
+    return NULL;
+}
+
 /**
  * Called when a receive PDU has started.
  * Check if the frame is the next expected CS_SYNC packet.
@@ -72,7 +220,14 @@ ble_ll_cs_sync_rx_sched_cb(struct ble_ll_sched_item *sch)
 int
 ble_ll_cs_sync_rx_isr_start(struct ble_mbuf_hdr *rxhdr, uint32_t aa)
 {
-    /* TODO: Verify CS Access Address */
+    struct ble_ll_cs_sm *cssm;
+
+    cssm = ble_ll_cs_sync_find_sm_match_aa(aa);
+
+    if (cssm == NULL) {
+        /* This is not the expected packet. Skip the frame. */
+        return -1;
+    }
 
     return 0;
 }
@@ -96,16 +251,16 @@ ble_ll_cs_sync_rx_isr_end(uint8_t *rxbuf, struct ble_mbuf_hdr *rxhdr)
     struct os_mbuf *rxpdu;
     struct ble_ll_cs_sm *cssm = g_ble_ll_cs_sm_current;
 
-    assert(cssm != NULL);
-    ble_ll_cs_proc_set_now_as_anchor_point(cssm);
-    ble_ll_cs_proc_schedule_next_tx_or_rx(cssm);
-
     /* Packet type was verified in isr_start */
 
     rxpdu = ble_ll_rxpdu_alloc(rxbuf[1] + BLE_LL_PDU_HDR_LEN);
     if (rxpdu) {
         ble_phy_rxpdu_copy(rxbuf, rxpdu);
 
+        assert(cssm != NULL);
+        ble_ll_cs_proc_set_now_as_anchor_point(cssm);
+        ble_ll_cs_proc_schedule_next_tx_or_rx(cssm);
+
         /* Send the packet to Link Layer context */
         ble_ll_rx_pdu_in(rxpdu);
     }