[nrf fromtree] drivers: ieee802154: copy back the TX buffer into the upper

... layer

Copy back the TX buffer content back into the upper layer
in case of a TX failure.

This is necessary in when frame encryption by the radio driver
is used. The shim layer for the nRF5 driver has a buffer, that
is used by the driver to authenticate and encrypt the frame
in-place. In case of a TX failure, the buffer contents
are propagated back to the upper layer. The upper layer
must use the same secured frame for retransmission.

Signed-off-by: Rafał Kuźnia <[email protected]>

Author: e-rk

drivers/ieee802154/ieee802154_nrf5.c

@@ -518,6 +518,7 @@ static int nrf5_tx(const struct device *dev,
 	uint8_t payload_len = frag->len;
 	uint8_t *payload = frag->data;
 	bool ret = true;
+	int result;
 
 	LOG_DBG("%p (%u)", payload, payload_len);
 
@@ -575,19 +576,32 @@ static int nrf5_tx(const struct device *dev,
 		/* Handle ACK packet. */
 		return handle_ack(nrf5_radio);
 	case NRF_802154_TX_ERROR_NO_MEM:
-		return -ENOBUFS;
+		result = -ENOBUFS;
 	case NRF_802154_TX_ERROR_BUSY_CHANNEL:
-		return -EBUSY;
+		result = -EBUSY;
 	case NRF_802154_TX_ERROR_INVALID_ACK:
 	case NRF_802154_TX_ERROR_NO_ACK:
-		return -ENOMSG;
+		result = -ENOMSG;
 	case NRF_802154_TX_ERROR_ABORTED:
 	case NRF_802154_TX_ERROR_TIMESLOT_DENIED:
 	case NRF_802154_TX_ERROR_TIMESLOT_ENDED:
-		return -EIO;
+	default:
+		result = -EIO;
 	}
 
-	return -EIO;
+#if NRF_802154_ENCRYPTION_ENABLED
+	/*
+	 * When frame encryption by the radio driver is enabled,
+	 * the frame stored in the tx_psdu buffer is authenticated
+	 * and encrypted in place. After an unsuccessful TX attempt,
+	 * this frame must be propagated back to the upper layer
+	 * for retransmission. The upper layer must ensure that the
+	 * excact same secured frame is used for retransmission.
+	 */
+	memcpy(payload, nrf5_radio->tx_psdu + 1, payload_len);
+#endif
+
+	return result;
 }
 
 static uint64_t nrf5_get_time(const struct device *dev)