SIDEKIQ: fix tx time protection

lib/src/phy/rf/rf_skiq_imp.c

@@ -898,6 +898,7 @@ int rf_skiq_send_timed_multi(void*  h_,
   if (is_start_of_burst) {
     if (has_time_spec) {
       h->next_tstamp = time_to_tstamp(h, secs, frac_secs);
+      SKIQ_RF_DEBUG("[Tx SOB] ts=%ld\n", h->next_tstamp);
     } else {
       h->next_tstamp = rf_skiq_card_read_rf_timestamp(&h->cards[0]);
       h->next_tstamp += (uint64_t)round(h->current_srate_hz / 10); // increment a 10th of a second

lib/src/phy/rf/rf_skiq_imp_cfg.h

@@ -100,4 +100,11 @@ extern uint32_t rf_skiq_logging_level;
     }                                                                                                                  \
   } while (false)
 
-#endif // SRSRAN_RF_SKIQ_IMP_CFG_H
+#define SKIQ_RF_ERROR(...)                                                                                             \
+  do {                                                                                                                 \
+    if (rf_skiq_logging_level >= SKIQ_LOG_ERROR) {                                                                     \
+      fprintf(stdout, "[SKIQ RF ERROR] " __VA_ARGS__);                                                                 \
+    }                                                                                                                  \
+  } while (false)
+
+#endif // SRSLTE_RF_SKIQ_IMP_CFG_H

lib/src/phy/rf/rf_skiq_imp_port.c

@@ -84,25 +84,44 @@ static void* writer_thread(void* arg)
       break;
     }
 
+    // If the ring buffer read resulted in timeout
+    if (n == SRSRAN_ERROR_TIMEOUT) {
+      continue;
+    }
+
     // Ignore blocks with TS=0
-    if (q->p_tx_block->timestamp == 0) {
+    if (p_tx_block->timestamp == 0) {
       continue;
     }
 
     // Check if the timestamp is the past (this can be caused by sample rate change)
-    if (last_tx_ts > q->p_tx_block->timestamp) {
-      skiq_read_curr_tx_timestamp(q->card, q->hdl, &last_tx_ts);
-      if (last_tx_ts > q->p_tx_block->timestamp) {
-        ERROR("Tx block (ts=%ld) is in the past (%ld), ignoring\n", q->p_tx_block->timestamp, last_tx_ts);
+    if (last_tx_ts > p_tx_block->timestamp) {
+
+      // Get current RF timestamp
+      uint64_t curr_tx_ts = 0UL;
+      skiq_read_curr_tx_timestamp(q->card, q->hdl, &curr_tx_ts);
+
+      // Avoids giving a block to the FPGA that has already passed, otherwise it could hang forever
+      if (curr_tx_ts > p_tx_block->timestamp) {
+        SKIQ_RF_ERROR("[Tx %d:%d block] Tx block (ts=%ld) is in the past (last_tx_ts=%ld, curr_tx_ts=%ld), ignoring\n",
+                      q->card,
+                      (int)q->hdl,
+                      q->p_tx_block->timestamp,
+                      last_tx_ts,
+                      curr_tx_ts);
         continue;
       }
     }
-    last_tx_ts = q->p_tx_block->timestamp + q->block_size;
+    last_tx_ts = p_tx_block->timestamp + q->block_size;
 
     // If the ring-buffer did not return with error code...
     if (n > SRSRAN_SUCCESS) {
-      SKIQ_RF_DEBUG(
-          "[Tx %d:%d block] ts=%ld; nsamples=%d;\n", q->card, (int)q->hdl, p_tx_block->timestamp, q->block_size);
+      SKIQ_RF_DEBUG("[Tx %d:%d block] ts=%ld; nsamples=%d; last_tx_ts=%ld;\n",
+                    q->card,
+                    (int)q->hdl,
+                    p_tx_block->timestamp,
+                    q->block_size,
+                    last_tx_ts);
 
       if (skiq_transmit(q->card, q->hdl, p_tx_block, NULL) < 0) {
         ERROR("Error transmitting card %d\n", q->card);
@@ -247,7 +266,7 @@ void rf_skiq_tx_port_end_of_burst(rf_skiq_tx_port_t* q)
     // Write block into the ring-buffer
     srsran_ringbuffer_write_block(&q->rb, q->p_tx_block, q->p_block_nbytes);
 
-    SKIQ_RF_DEBUG("[Tx %d:%d] Padding offset=%d; n=%d; ts=%ld\n",
+    SKIQ_RF_DEBUG("[Tx EOB %d:%d] Padding offset=%d; n=%d; ts=%ld\n",
                   q->card,
                   (int)q->hdl,
                   q->next_offset,
@@ -268,6 +287,11 @@ int rf_skiq_tx_port_send(rf_skiq_tx_port_t* q, const cf_t* buffer, uint32_t nsam
     return nsamples;
   }
 
+  // If no data and no block has started, early return
+  if (buffer == NULL && q->next_offset == 0) {
+    return nsamples;
+  }
+
   pthread_mutex_lock(&q->mutex);
 
   // Calculate destination where IQ shall be stored
@@ -390,6 +414,7 @@ int rf_skiq_rx_port_init(rf_skiq_rx_port_t* q, uint8_t card, skiq_rx_hdl_t hdl,
 
 void rf_skiq_rx_port_free(rf_skiq_rx_port_t* q)
 {
+
   srsran_ringbuffer_free(&q->rb);
 }