Harald Welte has submitted this change and it was merged. (
https://gerrit.osmocom.org/10455 )
Change subject: trxcon/sched_prim.c: properly handle both TCH/H and FACCH/H
prims
......................................................................
trxcon/sched_prim.c: properly handle both TCH/H and FACCH/H prims
Initially it was assumed that FACCH prioritization should be done
in the same way for both TCH/F and TCH/H. Moreover, it was not
possible to confirm this, because TCH/H was (and still) not
implemented yet. But according to the specs:
- unlike FACCH/F, FACCH/H transmissions shall be aligned
within a multiframe, i.e. can only be initiated on
particular frame numbers (see GSM 05.02, clause 7);
- unlike FACCH/F, a FACCH/H frame steals two TCH/F frames;
so the TCH/H (including FACCH/H) primitives should be handled
separately from the TCH/F (including FACCH/F) primitives.
Change-Id: I9b59f60e1cbac8fb8fd557b6c67b5e376c0a6bbb
---
M src/host/trxcon/sched_prim.c
M src/host/trxcon/sched_trx.c
M src/host/trxcon/sched_trx.h
3 files changed, 86 insertions(+), 6 deletions(-)
Approvals:
Jenkins Builder: Verified
Harald Welte: Looks good to me, approved
diff --git a/src/host/trxcon/sched_prim.c b/src/host/trxcon/sched_prim.c
index 4987379..acd08bf 100644
--- a/src/host/trxcon/sched_prim.c
+++ b/src/host/trxcon/sched_prim.c
@@ -223,25 +223,105 @@
}
/**
+ * Dequeues either a TCH/H, or a FACCH/H prim (preferred).
+ * If a FACCH/H prim is found, two TCH/H prims are being
+ * dropped (i.e. replaced).
+ *
+ * According to GSM 05.02, the following blocks can be used
+ * to carry FACCH/H data (see clause 7, table 1 of 9):
+ *
+ * UL FACCH/H0:
+ * B0(0,2,4,6,8,10), B1(8,10,13,15,17,19), B2(17,19,21,23,0,2)
+ *
+ * UL FACCH/H1:
+ * B0(1,3,5,7,9,11), B1(9,11,14,16,18,20), B2(18,20,22,24,1,3)
+ *
+ * where the numbers within brackets are fn % 26.
+ *
+ * @param queue transmit queue to take a prim from
+ * @param fn the current frame number
+ * @param lchan_type required channel type of a primitive,
+ * @return either a FACCH/H, or a TCH/H primitive,
+ * otherwise NULL
+ */
+static struct trx_ts_prim *prim_dequeue_tch_h(struct llist_head *queue,
+ uint32_t fn, enum trx_lchan_type lchan_type)
+{
+ struct trx_ts_prim *facch;
+ struct trx_ts_prim *tch;
+ bool facch_now = false;
+ uint32_t fn_mf;
+
+ /* Traffic multiframe period */
+ fn_mf = fn % 26;
+
+ /* FACCH/H0 frame alignment */
+ if (lchan_type == TRXC_TCHH_0)
+ if (fn_mf == 0 || fn_mf == 8 || fn_mf == 17)
+ facch_now = true;
+
+ /* FACCH/H1 frame alignment */
+ if (lchan_type == TRXC_TCHH_1)
+ if (fn_mf == 1 || fn_mf == 9 || fn_mf == 18)
+ facch_now = true;
+
+ /* If FACCH/H is not allowed for a given frame number */
+ if (!facch_now) /* Just dequeue a TCH/H prim */
+ goto no_facch;
+
+ /* If there are no FACCH/H prims in the queue */
+ facch = prim_dequeue_tch(queue, lchan_type, true);
+ if (!facch) /* Just dequeue a TCH/H prim */
+ goto no_facch;
+
+ /* FACCH/H prim replaces two TCH/F prims */
+ tch = prim_dequeue_tch(queue, lchan_type, false);
+ if (tch) {
+ /* At least one TCH/H prim is dropped */
+ talloc_free(tch);
+
+ /* Attempt to find another */
+ tch = prim_dequeue_tch(queue, lchan_type, false);
+ if (tch) /* Drop the second TCH/H prim */
+ talloc_free(tch);
+ }
+
+ return facch;
+
+no_facch:
+ return prim_dequeue_tch(queue, lchan_type, false);
+}
+
+/**
* Dequeues a single primitive of required type
* from a specified transmit queue.
*
* @param queue a transmit queue to take a prim from
+ * @param fn the current frame number (used for FACCH/H)
* @param lchan_type required primitive type
* @return a primitive or NULL if not found
*/
struct trx_ts_prim *sched_prim_dequeue(struct llist_head *queue,
- enum trx_lchan_type lchan_type)
+ uint32_t fn, enum trx_lchan_type lchan_type)
{
/* There is nothing to dequeue */
if (llist_empty(queue))
return NULL;
- /* TCH requires FACCH prioritization, so handle it separately */
- if (CHAN_IS_TCH(lchan_type))
+ switch (lchan_type) {
+ /* TCH/F requires FACCH/F prioritization */
+ case TRXC_TCHF:
return prim_dequeue_tch_f(queue);
- return prim_dequeue_one(queue, lchan_type);
+ /* FACCH/H prioritization is a bit more complex */
+ case TRXC_TCHH_0:
+ case TRXC_TCHH_1:
+ return prim_dequeue_tch_h(queue, fn, lchan_type);
+
+ /* Other kinds of logical channels */
+ default:
+ return prim_dequeue_one(queue, lchan_type);
+ }
}
/**
diff --git a/src/host/trxcon/sched_trx.c b/src/host/trxcon/sched_trx.c
index c263ce7..fd43a56 100644
--- a/src/host/trxcon/sched_trx.c
+++ b/src/host/trxcon/sched_trx.c
@@ -95,7 +95,7 @@
* attempt to obtain a new one from queue
*/
if (lchan->prim == NULL)
- lchan->prim = sched_prim_dequeue(&ts->tx_prims, chan);
+ lchan->prim = sched_prim_dequeue(&ts->tx_prims, fn,
chan);
/* TODO: report TX buffers health to the higher layers */
diff --git a/src/host/trxcon/sched_trx.h b/src/host/trxcon/sched_trx.h
index cd9c0e4..f3fa9df 100644
--- a/src/host/trxcon/sched_trx.h
+++ b/src/host/trxcon/sched_trx.h
@@ -302,7 +302,7 @@
(CHAN_IS_TCH(prim->chan) && prim->payload_len == GSM_MACBLOCK_LEN)
struct trx_ts_prim *sched_prim_dequeue(struct llist_head *queue,
- enum trx_lchan_type lchan_type);
+ uint32_t fn, enum trx_lchan_type lchan_type);
int sched_prim_dummy(struct trx_lchan_state *lchan);
void sched_prim_drop(struct trx_lchan_state *lchan);
void sched_prim_flush_queue(struct llist_head *list);
--
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Gerrit-Project: osmocom-bb
Gerrit-Branch: master
Gerrit-MessageType: merged
Gerrit-Change-Id: I9b59f60e1cbac8fb8fd557b6c67b5e376c0a6bbb
Gerrit-Change-Number: 10455
Gerrit-PatchSet: 1
Gerrit-Owner: Vadim Yanitskiy <axilira...@gmail.com>
Gerrit-Reviewer: Harald Welte <lafo...@gnumonks.org>
Gerrit-Reviewer: Jenkins Builder
