lapdm: introduce a new lapdm_phsap_dequeue_prim()

This function can be called by a TDMA-driven L1 which will never actually want
to receive unsolicited/asynchronous PH-DATA.req primitives, but who will simply
directly poll the LAPDm transmit queue by calling the abovementioned function

diff --git a/src/host/layer23/include/osmocom/bb/common/lapdm.h b/src/host/layer23/include/osmocom/bb/common/lapdm.h
index 946ca27..2e78aee 100644 (file)
--- a/src/host/layer23/include/osmocom/bb/common/lapdm.h
+++ b/src/host/layer23/include/osmocom/bb/common/lapdm.h
@@ -181,4 +181,6 @@ void lapdm_channel_reset(struct lapdm_channel *lc);
 void lapdm_entity_set_flags(struct lapdm_entity *le, unsigned int flags);
 void lapdm_channel_set_flags(struct lapdm_channel *lc, unsigned int flags);
 
+int lapdm_phsap_dequeue_prim(struct lapdm_entity *le, struct osmo_phsap_prim *pp);
+
 #endif /* _OSMOCOM_LAPDM_H */

diff --git a/src/host/layer23/src/common/lapdm.c b/src/host/layer23/src/common/lapdm.c
index e5e23f3..fd395ef 100644 (file)
--- a/src/host/layer23/src/common/lapdm.c
+++ b/src/host/layer23/src/common/lapdm.c
@@ -331,23 +331,12 @@ static int tx_ph_data_enqueue(struct lapdm_datalink *dl, struct msgb *msg,
        return le->l1_prim_cb(&pp.oph, le->l1_ctx);
 }
 
-/* get next frame from the tx queue. because the ms has multiple datalinks,
- * each datalink's queue is read round-robin.
- */
-static int l2_ph_data_conf(struct msgb *msg, struct lapdm_entity *le)
+static struct msgb *tx_dequeue_msgb(struct lapdm_entity *le)
 {
        struct lapdm_datalink *dl;
        int last = le->last_tx_dequeue;
        int i = last, n = ARRAY_SIZE(le->datalink);
-       struct osmo_phsap_prim pp;
-       uint8_t n201;
-
-       /* we may send again */
-       le->tx_pending = 0;
-
-       /* free confirm message */
-       if (msg)
-               msgb_free(msg);
+       struct msgb *msg = NULL;
 
        /* round-robin dequeue */
        do {
@@ -358,7 +347,58 @@ static int l2_ph_data_conf(struct msgb *msg, struct lapdm_entity *le)
                        break;
        } while (i != last);
 
-       if (!msg) {
+       if (msg) {
+               /* Set last dequeue position */
+               le->last_tx_dequeue = i;
+       }
+
+       return msg;
+}
+
+/* dequeue a msg that's pending transmission via L1 and wrap it into
+ * a osmo_phsap_prim */
+int lapdm_phsap_dequeue_prim(struct lapdm_entity *le, struct osmo_phsap_prim *pp)
+{
+       struct msgb *msg;
+       uint8_t n201;
+
+       msg = tx_dequeue_msgb(le);
+       if (!msg)
+               return -ENODEV;
+
+       /* if we have a message, send PH-DATA.req */
+       osmo_prim_init(&pp->oph, SAP_GSM_PH, PRIM_PH_DATA,
+                       PRIM_OP_REQUEST, msg);
+
+       /* Pull chan_nr and link_id */
+       pp->u.data.chan_nr = *msg->data;
+       msgb_pull(msg, 1);
+       pp->u.data.link_id = *msg->data;
+       msgb_pull(msg, 1);
+       n201 = *msg->data;
+       msgb_pull(msg, 1);
+
+       /* Pad the frame, we can transmit now */
+       lapdm_pad_msgb(msg, n201);
+
+       return 0;
+}
+
+/* get next frame from the tx queue. because the ms has multiple datalinks,
+ * each datalink's queue is read round-robin.
+ */
+static int l2_ph_data_conf(struct msgb *msg, struct lapdm_entity *le)
+{
+       struct osmo_phsap_prim pp;
+
+       /* we may send again */
+       le->tx_pending = 0;
+
+       /* free confirm message */
+       if (msg)
+               msgb_free(msg);
+
+       if (lapdm_phsap_dequeue_prim(le, &pp) < 0) {
                /* no message in all queues */
 
                /* If user didn't request PH-EMPTY_FRAME.req, abort */
@@ -370,24 +410,7 @@ static int l2_ph_data_conf(struct msgb *msg, struct lapdm_entity *le)
                                PRIM_PH_EMPTY_FRAME,
                                PRIM_OP_REQUEST, NULL);
        } else {
-               /* if we have a message, send PH-DATA.req */
-               osmo_prim_init(&pp.oph, SAP_GSM_PH, PRIM_PH_DATA,
-                               PRIM_OP_REQUEST, msg);
-
-               /* Pull chan_nr and link_id */
-               pp.u.data.chan_nr = *msg->data;
-               msgb_pull(msg, 1);
-               pp.u.data.link_id = *msg->data;
-               msgb_pull(msg, 1);
-               n201 = *msg->data;
-               msgb_pull(msg, 1);
-
-               /* Set last dequeue position */
-               le->last_tx_dequeue = i;
-
-               /* Pad the frame, we can transmit now */
                le->tx_pending = 1;
-               lapdm_pad_msgb(msg, n201);
        }
 
        return le->l1_prim_cb(&pp.oph, le->l1_ctx);