nimble/controller: Move latency calculations to ble_ll_conn_calc_dci

This is to localize CSA #2 related code in order for easier compile
time configuration.

X-Original-Commit: 3acdf385fa4bfc94081005d359073f0e114825b6

nimble/controller/include/controller/ble_ll_conn.h

@@ -152,7 +152,6 @@ struct ble_ll_conn_sm
     uint16_t channel_id; /* TODO could be union with hop and last chan used */
     uint8_t hop_inc;
     uint8_t data_chan_index;
-    uint8_t unmapped_chan;
     uint8_t last_unmapped_chan;
     uint8_t num_used_chans;
 
@@ -288,7 +287,7 @@ struct ble_ll_conn_sm
 struct ble_ll_conn_sm *ble_ll_conn_find_active_conn(uint16_t handle);
 
 /* required for unit testing */
-uint8_t ble_ll_conn_calc_dci(struct ble_ll_conn_sm *conn);
+uint8_t ble_ll_conn_calc_dci(struct ble_ll_conn_sm *conn, uint16_t latency);
 
 #ifdef __cplusplus
 }

nimble/controller/src/ble_ll_conn.c

@@ -664,33 +664,21 @@ ble_ll_conn_calc_dci_csa2(struct ble_ll_conn_sm *conn)
     return ble_ll_conn_remapped_channel(remap_index, conn->chanmap);
 }
 
-/**
- * Determine data channel index to be used for the upcoming/current
- * connection event
- *
- * @param conn
- *
- * @return uint8_t
- */
-uint8_t
-ble_ll_conn_calc_dci(struct ble_ll_conn_sm *conn)
+static uint8_t
+ble_ll_conn_calc_dci_csa1(struct ble_ll_conn_sm *conn)
 {
     uint8_t curchan;
     uint8_t remap_index;
     uint8_t bitpos;
 
-    if (CONN_F_CSA2_SUPP(conn)) {
-        return ble_ll_conn_calc_dci_csa2(conn);
-    }
-
     /* Get next unmapped channel */
     curchan = conn->last_unmapped_chan + conn->hop_inc;
     if (curchan > BLE_PHY_NUM_DATA_CHANS) {
         curchan -= BLE_PHY_NUM_DATA_CHANS;
     }
 
-    /* Set the current unmapped channel */
-    conn->unmapped_chan = curchan;
+    /* Save unmapped channel */
+    conn->last_unmapped_chan = curchan;
 
     /* Is this a valid channel? */
     bitpos = 1 << (curchan & 0x07);
@@ -704,6 +692,34 @@ ble_ll_conn_calc_dci(struct ble_ll_conn_sm *conn)
     return ble_ll_conn_remapped_channel(remap_index, conn->chanmap);
 }
 
+/**
+ * Determine data channel index to be used for the upcoming/current
+ * connection event
+ *
+ * @param conn
+ * @param latency Used only for CSA #1
+ *
+ * @return uint8_t
+ */
+uint8_t
+ble_ll_conn_calc_dci(struct ble_ll_conn_sm *conn, uint16_t latency)
+{
+    uint8_t index;
+
+    if (CONN_F_CSA2_SUPP(conn)) {
+        return ble_ll_conn_calc_dci_csa2(conn);
+    }
+
+    index = conn->data_chan_index;
+
+    while (latency > 0) {
+        index = ble_ll_conn_calc_dci_csa1(conn);
+        latency--;
+    }
+
+    return index;
+}
+
 /**
  * Called when we are in the connection state and the wait for response timer
  * fires off.
@@ -1583,12 +1599,12 @@ ble_ll_conn_set_csa(struct ble_ll_conn_sm *connsm, bool chsel)
         connsm->channel_id = ((connsm->access_addr & 0xffff0000) >> 16) ^
                               (connsm->access_addr & 0x0000ffff);
 
-        connsm->data_chan_index = ble_ll_conn_calc_dci(connsm);
+        connsm->data_chan_index = ble_ll_conn_calc_dci(connsm, 0);
         return;
     }
 
     connsm->last_unmapped_chan = 0;
-    connsm->data_chan_index = ble_ll_conn_calc_dci(connsm);
+    connsm->data_chan_index = ble_ll_conn_calc_dci(connsm, 1);
 }
 
 /**
@@ -1949,15 +1965,7 @@ ble_ll_conn_next_event(struct ble_ll_conn_sm *connsm)
     }
 
     /* Calculate data channel index of next connection event */
-    if (CONN_F_CSA2_SUPP(connsm)) {
-        connsm->data_chan_index = ble_ll_conn_calc_dci(connsm);
-    } else {
-        while (latency > 0) {
-            connsm->last_unmapped_chan = connsm->unmapped_chan;
-            connsm->data_chan_index = ble_ll_conn_calc_dci(connsm);
-            --latency;
-        }
-    }
+    connsm->data_chan_index = ble_ll_conn_calc_dci(connsm, latency);
 
     /*
      * If we are trying to terminate connection, check if next wake time is

nimble/controller/test/src/ble_ll_csa2_test.c

@@ -53,15 +53,15 @@ TEST_CASE(ble_ll_csa2_test_1)
     conn.chanmap[3] = 0x1f;
 
     conn.event_cntr = 1;
-    rc = ble_ll_conn_calc_dci(&conn);
+    rc = ble_ll_conn_calc_dci(&conn, 0);
     TEST_ASSERT(rc == 20);
 
     conn.event_cntr = 2;
-    rc = ble_ll_conn_calc_dci(&conn);
+    rc = ble_ll_conn_calc_dci(&conn, 0);
     TEST_ASSERT(rc == 6);
 
     conn.event_cntr = 3;
-    rc = ble_ll_conn_calc_dci(&conn);
+    rc = ble_ll_conn_calc_dci(&conn, 0);
     TEST_ASSERT(rc == 21);
 }
 
@@ -95,15 +95,15 @@ TEST_CASE(ble_ll_csa2_test_2)
     conn.chanmap[4] = 0x1e;
 
     conn.event_cntr = 6;
-    rc = ble_ll_conn_calc_dci(&conn);
+    rc = ble_ll_conn_calc_dci(&conn, 0);
     TEST_ASSERT(rc == 23);
 
     conn.event_cntr = 7;
-    rc = ble_ll_conn_calc_dci(&conn);
+    rc = ble_ll_conn_calc_dci(&conn, 0);
     TEST_ASSERT(rc == 9);
 
     conn.event_cntr = 8;
-    rc = ble_ll_conn_calc_dci(&conn);
+    rc = ble_ll_conn_calc_dci(&conn, 0);
     TEST_ASSERT(rc == 34);
 }