Vadim Yanitskiy has uploaded this change for review. (
https://gerrit.osmocom.org/10942
Change subject: trxcon/scheduler: introduce TDMA frame math helpers
......................................................................
trxcon/scheduler: introduce TDMA frame math helpers
The 'normal' math operations, such as addition and substraction,
are not applicable for TDMA frame numbers because they may result
in out-of-range values.
Having TDMA frame math helpers in a single place would allow
one to avoid possible out-of-range result mistakes.
Change-Id: Ibb66ba846cc3d6c2eaa88414569e5f3751128047
---
M src/host/trxcon/sched_clck.c
M src/host/trxcon/sched_trx.c
M src/host/trxcon/scheduler.h
3 files changed, 16 insertions(+), 12 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmocom-bb refs/changes/42/10942/1
diff --git a/src/host/trxcon/sched_clck.c b/src/host/trxcon/sched_clck.c
index 56b89a2..8a9527c 100644
--- a/src/host/trxcon/sched_clck.c
+++ b/src/host/trxcon/sched_clck.c
@@ -84,8 +84,7 @@
timespecadd(tv_clock, &frame_duration, tv_clock);
elapsed_us -= FRAME_DURATION_uS;
- sched->fn_counter_proc = (sched->fn_counter_proc + 1)
- % GSM_HYPERFRAME;
+ sched->fn_counter_proc = TDMA_FN_INC(sched->fn_counter_proc);
/* Call frame callback */
if (sched->clock_cb)
@@ -143,8 +142,7 @@
/* Calculate elapsed time / frames since last processed fn */
timespecsub(&tv_now, tv_clock, &elapsed);
elapsed_us = (elapsed.tv_sec * 1000000) + (elapsed.tv_nsec / 1000);
- elapsed_fn = (fn + GSM_HYPERFRAME - sched->fn_counter_proc)
- % GSM_HYPERFRAME;
+ elapsed_fn = TDMA_FN_SUB(fn, sched->fn_counter_proc);
if (elapsed_fn >= 135774)
elapsed_fn -= GSM_HYPERFRAME;
@@ -182,8 +180,7 @@
/* Transmit what we still need to transmit */
while (fn != sched->fn_counter_proc) {
- sched->fn_counter_proc = (sched->fn_counter_proc + 1)
- % GSM_HYPERFRAME;
+ sched->fn_counter_proc = TDMA_FN_INC(sched->fn_counter_proc);
/* Call frame callback */
if (sched->clock_cb)
diff --git a/src/host/trxcon/sched_trx.c b/src/host/trxcon/sched_trx.c
index 8bd3c72..e20da39 100644
--- a/src/host/trxcon/sched_trx.c
+++ b/src/host/trxcon/sched_trx.c
@@ -65,8 +65,8 @@
* Advance frame number, giving the transceiver more
* time until a burst must be transmitted...
*/
- fn = (sched->fn_counter_proc + sched->fn_counter_advance)
- % GSM_HYPERFRAME;
+ fn = TDMA_FN_SUM(sched->fn_counter_proc,
+ sched->fn_counter_advance);
/* Get frame from multiframe */
offset = fn % ts->mf_layout->period;
@@ -608,15 +608,14 @@
}
/* Calculate how many frames have been elapsed */
- elapsed = (burst_fn + GSM_HYPERFRAME - ts->mf_last_fn);
- elapsed %= GSM_HYPERFRAME;
+ elapsed = TDMA_FN_SUB(burst_fn, ts->mf_last_fn);
/**
* If not too many frames have been elapsed,
* start counting from last fn + 1
*/
if (elapsed < 10)
- fn = (ts->mf_last_fn + 1) % GSM_HYPERFRAME;
+ fn = TDMA_FN_INC(ts->mf_last_fn);
else
fn = burst_fn;
@@ -658,7 +657,7 @@
if (fn == burst_fn)
break;
- fn = (fn + 1) % GSM_HYPERFRAME;
+ fn = TDMA_FN_INC(fn);
}
/* Set last processed frame number */
diff --git a/src/host/trxcon/scheduler.h b/src/host/trxcon/scheduler.h
index 6c3a2f2..6b70b41 100644
--- a/src/host/trxcon/scheduler.h
+++ b/src/host/trxcon/scheduler.h
@@ -8,6 +8,14 @@
#define GSM_SUPERFRAME (26 * 51)
#define GSM_HYPERFRAME (2048 * GSM_SUPERFRAME)
+/* TDMA frame number arithmetics */
+#define TDMA_FN_INC(fn) \
+ ((fn + 1) % GSM_HYPERFRAME)
+#define TDMA_FN_SUM(a, b) \
+ ((a + b) % GSM_HYPERFRAME)
+#define TDMA_FN_SUB(a, b) \
+ ((a + GSM_HYPERFRAME - b) % GSM_HYPERFRAME)
+
enum tdma_sched_clck_state {
SCH_CLCK_STATE_WAIT,
SCH_CLCK_STATE_OK,
--
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Gerrit-Project: osmocom-bb
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: Ibb66ba846cc3d6c2eaa88414569e5f3751128047
Gerrit-Change-Number: 10942
Gerrit-PatchSet: 1
Gerrit-Owner: Vadim Yanitskiy <[email protected]>
