src/target/firmware/layer1/prim_fbsb.c

   1 /* Layer 1 - FCCH and SCH burst handling */
   2
   3 /* (C) 2010 by Harald Welte <laforge@gnumonks.org>
   4  *
   5  * All Rights Reserved
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  */
  22
  23 #include <stdint.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26 #include <stdlib.h>
  27 #include <errno.h>
  28
  29 #include <defines.h>
  30 #include <debug.h>
  31 #include <memory.h>
  32 #include <byteorder.h>
  33 #include <osmocore/gsm_utils.h>
  34 #include <osmocore/msgb.h>
  35 #include <calypso/dsp_api.h>
  36 #include <calypso/irq.h>
  37 #include <calypso/tpu.h>
  38 #include <calypso/tsp.h>
  39 #include <calypso/dsp.h>
  40 #include <calypso/timer.h>
  41 #include <comm/sercomm.h>
  42
  43 #include <layer1/sync.h>
  44 #include <layer1/afc.h>
  45 #include <layer1/tdma_sched.h>
  46 #include <layer1/mframe_sched.h>
  47 #include <layer1/tpu_window.h>
  48 #include <layer1/l23_api.h>
  49
  50 #include <l1a_l23_interface.h>
  51
  52 #define FB0_RETRY_COUNT         3
  53 #define AFC_RETRY_COUNT         30
  54
  55 extern uint16_t rf_arfcn; // TODO
  56
  57 struct mon_state {
  58         uint32_t fnr_report;    /* frame number when DSP reported it */
  59         int attempt;            /* which attempt was this ? */
  60
  61         int16_t toa;
  62         uint16_t pm;
  63         uint16_t angle;
  64         uint16_t snr;
  65
  66         /* computed values */
  67         int16_t freq_diff;
  68
  69         /* Sync Burst (SB) */
  70         uint8_t bsic;
  71         struct gsm_time time;
  72 };
  73
  74 struct l1a_fb_state {
  75         struct mon_state mon;
  76         struct l1ctl_fbsb_req req;
  77         int16_t initial_freq_err;
  78         uint8_t fb_retries;
  79         uint8_t afc_retries;
  80 };
  81
  82 static struct l1a_fb_state fbs;
  83 static struct mon_state *last_fb = &fbs.mon;
  84
  85 static void dump_mon_state(struct mon_state *fb)
  86 {
  87 #if 0
  88         printf("(%u:%u): TOA=%5u, Power=%4ddBm, Angle=%5dHz, "
  89                 "SNR=%04x(%d.%u) OFFSET=%u SYNCHRO=%u\n",
  90                 fb->fnr_report, fb->attempt, fb->toa,
  91                 agc_inp_dbm8_by_pm(fb->pm)/8, ANGLE_TO_FREQ(fb->angle),
  92                 fb->snr, l1s_snr_int(fb->snr), l1s_snr_fract(fb->snr),
  93                 tpu_get_offset(), tpu_get_synchro());
  94 #else
  95         printf("(%u:%u): TOA=%5u, Power=%4ddBm, Angle=%5dHz\n",
  96                 fb->fnr_report, fb->attempt, fb->toa,
  97                 agc_inp_dbm8_by_pm(fb->pm)/8, ANGLE_TO_FREQ(fb->angle));
  98 #endif
  99 }
 100
 101 static int l1ctl_fbsb_resp(uint8_t res)
 102 {
 103         struct msgb *msg;
 104         struct l1ctl_fbsb_resp *resp;
 105
 106         msg = l1_create_l2_msg(L1CTL_FBSB_RESP, fbs.mon.time.fn,
 107                                 l1s_snr_int(fbs.mon.snr),
 108                                 fbs.req.band_arfcn);
 109         if (!msg)
 110                 return -ENOMEM;
 111
 112         resp = (struct l1ctl_fbsb_resp *) msgb_put(msg, sizeof(*resp));
 113         resp->initial_freq_err = htons(fbs.initial_freq_err);
 114         resp->result = res;
 115         resp->bsic = fbs.mon.bsic;
 116
 117         /* no need to set BSIC, as it is never used here */
 118         l1_queue_for_l2(msg);
 119
 120         return 0;
 121 }
 122
 123 /* SCH Burst Detection ********************************************************/
 124
 125 /* determine the GSM time and BSIC from a Sync Burst */
 126 static uint8_t l1s_decode_sb(struct gsm_time *time, uint32_t sb)
 127 {
 128         uint8_t bsic = (sb >> 2) & 0x3f;
 129         uint8_t t3p;
 130
 131         memset(time, 0, sizeof(*time));
 132
 133         /* TS 05.02 Chapter 3.3.2.2.1 SCH Frame Numbers */
 134         time->t1 = ((sb >> 23) & 1) | ((sb >> 7) & 0x1fe) | ((sb << 9) & 0x600);
 135         time->t2 = (sb >> 18) & 0x1f;
 136         t3p = ((sb >> 24) & 1) | ((sb >> 15) & 6);
 137         time->t3 = t3p*10 + 1;
 138
 139         /* TS 05.02 Chapter 4.3.3 TDMA frame number */
 140         time->fn = gsm_gsmtime2fn(time);
 141
 142         time->tc = (time->fn / 51) % 8;
 143
 144         return bsic;
 145 }
 146
 147 static void read_sb_result(struct mon_state *st, int attempt)
 148 {
 149         st->toa = dsp_api.db_r->a_serv_demod[D_TOA];
 150         st->pm = dsp_api.db_r->a_serv_demod[D_PM]>>3;
 151         st->angle = dsp_api.db_r->a_serv_demod[D_ANGLE];
 152         st->snr = dsp_api.db_r->a_serv_demod[D_SNR];
 153
 154         st->freq_diff = ANGLE_TO_FREQ(st->angle);
 155         st->fnr_report = l1s.current_time.fn;
 156         st->attempt = attempt;
 157
 158         dump_mon_state(st);
 159
 160         if (st->snr > AFC_SNR_THRESHOLD)
 161                 afc_input(st->freq_diff, rf_arfcn, 1);
 162         else
 163                 afc_input(st->freq_diff, rf_arfcn, 0);
 164
 165         dsp_api.r_page_used = 1;
 166 }
 167
 168 /* Note: When we get the SB response, it is 2 TDMA frames after the SB
 169  * actually happened, as it is a "C W W R" task */
 170 #define SB2_LATENCY     2
 171
 172 static int l1s_sbdet_resp(__unused uint8_t p1, uint8_t attempt,
 173                           __unused uint16_t p3)
 174 {
 175         uint32_t sb;
 176         int qbits, fn_offset;
 177         struct l1_cell_info *cinfo = &l1s.serving_cell;
 178         int fnr_delta, bits_delta;
 179         struct l1ctl_sync_new_ccch_resp *l1;
 180         struct msgb *msg;
 181
 182         putchart('s');
 183
 184         if (dsp_api.db_r->a_sch[0] & (1<<B_SCH_CRC)) {
 185                 /* mark READ page as being used */
 186                 dsp_api.r_page_used = 1;
 187
 188                 /* after 2nd attempt, we failed */
 189                 if (attempt == 2) {
 190                         last_fb->attempt = 13;
 191                         l1s_compl_sched(L1_COMPL_FB);
 192                 }
 193
 194                 /* after 1st attempt, we simply wait for 2nd */
 195                 return 0;
 196         }
 197
 198         printf("SB%d ", attempt);
 199         read_sb_result(last_fb, attempt);
 200
 201         sb = dsp_api.db_r->a_sch[3] | dsp_api.db_r->a_sch[4] << 16;
 202         fbs.mon.bsic = l1s_decode_sb(&fbs.mon.time, sb);
 203         printf("=> SB 0x%08x: BSIC=%u ", sb, fbs.mon.bsic);
 204         l1s_time_dump(&fbs.mon.time);
 205
 206         l1s.serving_cell.bsic = fbs.mon.bsic;
 207
 208         /* calculate synchronisation value (TODO: only complete for qbits) */
 209         last_fb->toa -= 23;
 210         qbits = last_fb->toa * 4;
 211         fn_offset = l1s.current_time.fn; // TODO
 212
 213         if (qbits > QBITS_PER_TDMA) {
 214                 qbits -= QBITS_PER_TDMA;
 215                 fn_offset -= 1;
 216         } else if (qbits < 0)  {
 217                 qbits += QBITS_PER_TDMA;
 218                 fn_offset += 1;
 219         }
 220
 221         fnr_delta = last_fb->fnr_report - attempt;
 222         bits_delta = fnr_delta * BITS_PER_TDMA;
 223
 224         cinfo->fn_offset = fnr_delta;
 225         cinfo->time_alignment = qbits;
 226         cinfo->arfcn = rf_arfcn;
 227
 228         if (last_fb->toa > bits_delta)
 229                 printf("=> DSP reports SB in bit that is %d bits in the "
 230                         "future?!?\n", last_fb->toa - bits_delta);
 231         else
 232                 printf(" qbits=%u\n", qbits);
 233
 234         synchronize_tdma(&l1s.serving_cell);
 235
 236         /* if we have recived a SYNC burst, update our local GSM time */
 237         gsm_fn2gsmtime(&l1s.current_time, fbs.mon.time.fn + SB2_LATENCY);
 238         /* compute next time from new current time */
 239         l1s.next_time = l1s.current_time;
 240         l1s_time_inc(&l1s.next_time, 1);
 241
 242         /* If we call tdma_sched_reset(), which is only needed if there
 243          * are further l1s_sbdet_resp() scheduled, we will bring
 244          * dsp_api.db_r and dsp_api.db_w out of sync because we changed
 245          * dsp_api.db_w for l1s_sbdet_cmd() and canceled
 246          * l1s_sbdet_resp() which would change dsp_api.db_r. The DSP
 247          * however expects dsp_api.db_w and dsp_api.db_r to be in sync
 248          * (either "0 - 0" or "1 - 1"). So we have to bring dsp_api.db_w
 249          * and dsp_api.db_r into sync again, otherwise NB reading will
 250          * complain. We probably don't need the Abort command and could
 251          * just bring dsp_api.db_w and dsp_api.db_r into sync.  */
 252         if (attempt != 2) {
 253                 tdma_sched_reset();
 254                 l1s_dsp_abort();
 255         }
 256
 257         l1s_reset_hw();
 258         /* enable the MF Task for BCCH reading */
 259         mframe_enable(MF_TASK_BCCH_NORM);
 260         mframe_enable(MF_TASK_CCCH_COMB);
 261
 262         l1s_compl_sched(L1_COMPL_FB);
 263
 264         return 0;
 265 }
 266
 267 static int l1s_sbdet_cmd(__unused uint8_t p1, __unused uint8_t p2,
 268                          __unused uint16_t p3)
 269 {
 270         putchart('S');
 271
 272         fbs.mon.bsic = 0;
 273         fbs.mon.time.fn = 0;
 274
 275         dsp_api.db_w->d_task_md = SB_DSP_TASK;
 276         dsp_api.ndb->d_fb_mode = 0; /* wideband search */
 277         dsp_end_scenario();
 278
 279         /* Program TPU */
 280         l1s_rx_win_ctrl(rf_arfcn, L1_RXWIN_SB);
 281         tpu_end_scenario();
 282
 283         return 0;
 284 }
 285
 286 /* This is how it is done by the TSM30 */
 287 static const struct tdma_sched_item sb_sched_set[] = {
 288         SCHED_ITEM(l1s_sbdet_cmd, 0, 1),        SCHED_END_FRAME(),
 289         SCHED_ITEM(l1s_sbdet_cmd, 0, 2),        SCHED_END_FRAME(),
 290                                                 SCHED_END_FRAME(),
 291         SCHED_ITEM(l1s_sbdet_resp, 0, 1),       SCHED_END_FRAME(),
 292         SCHED_ITEM(l1s_sbdet_resp, 0, 2),       SCHED_END_FRAME(),
 293         SCHED_END_SET()
 294 };
 295
 296 void l1s_sb_test(uint8_t base_fn)
 297 {
 298         tdma_schedule_set(base_fn, sb_sched_set, 0);
 299 }
 300 /* FCCH Burst *****************************************************************/
 301
 302 static int read_fb_result(struct mon_state *st, int attempt)
 303 {
 304         st->toa = dsp_api.ndb->a_sync_demod[D_TOA];
 305         st->pm = dsp_api.ndb->a_sync_demod[D_PM]>>3;
 306         st->angle = dsp_api.ndb->a_sync_demod[D_ANGLE];
 307         st->snr = dsp_api.ndb->a_sync_demod[D_SNR];
 308
 309         //last_fb->angle = clip_int16(last_fb->angle, AFC_MAX_ANGLE);
 310         st->freq_diff = ANGLE_TO_FREQ(last_fb->angle);
 311         st->fnr_report = l1s.current_time.fn;
 312         st->attempt = attempt;
 313
 314         dump_mon_state(st);
 315
 316         dsp_api.ndb->d_fb_det = 0;
 317         dsp_api.ndb->a_sync_demod[D_TOA] = 0; /* TSM30 does it (really needed ?) */
 318
 319         /* Update AFC with current frequency offset */
 320         afc_correct(st->freq_diff, rf_arfcn);
 321
 322         //tpu_dsp_frameirq_enable();
 323         return 1;
 324 }
 325
 326 static void fbinfo2cellinfo(struct l1_cell_info *cinfo,
 327                             const struct mon_state *mon)
 328 {
 329         int ntdma, qbits, fn_offset, fnr_delta, bits_delta;
 330
 331         /* FIXME: where did this magic 23 come from? */
 332         last_fb->toa -= 23;
 333
 334         if (last_fb->toa < 0) {
 335                 qbits = (last_fb->toa + BITS_PER_TDMA) * 4;
 336                 ntdma = -1;
 337         } else {
 338                 ntdma = (last_fb->toa) / BITS_PER_TDMA;
 339                 qbits = (last_fb->toa - ntdma * BITS_PER_TDMA) * 4;
 340         }
 341
 342         fn_offset = l1s.current_time.fn - last_fb->attempt + ntdma;
 343         fnr_delta = last_fb->fnr_report - last_fb->attempt;
 344         bits_delta = fnr_delta * BITS_PER_TDMA;
 345
 346         cinfo->fn_offset = fnr_delta;
 347         cinfo->time_alignment = qbits;
 348         cinfo->arfcn = rf_arfcn;
 349
 350         if (last_fb->toa > bits_delta)
 351                 printf("=> DSP reports FB in bit that is %d bits in "
 352                         "the future?!?\n", last_fb->toa - bits_delta);
 353         else {
 354                 int fb_fnr = (last_fb->fnr_report - last_fb->attempt)
 355                                 + last_fb->toa/BITS_PER_TDMA;
 356                 printf("=>FB @ FNR %u fn_offset=%d qbits=%u\n",
 357                         fb_fnr, fn_offset, qbits);
 358         }
 359 }
 360
 361 /* scheduler callback to issue a FB detection task to the DSP */
 362 static int l1s_fbdet_cmd(__unused uint8_t p1, __unused uint8_t p2,
 363                          uint16_t fb_mode)
 364 {
 365         if (fb_mode == 0) {
 366                 putchart('F');
 367         } else {
 368                 putchart('V');
 369         }
 370
 371         l1s.fb.mode = fb_mode;
 372
 373         /* Program DSP */
 374         dsp_api.db_w->d_task_md = FB_DSP_TASK;  /* maybe with I/Q swap? */
 375         dsp_api.ndb->d_fb_mode = fb_mode;
 376         dsp_end_scenario();
 377
 378         /* Program TPU */
 379         l1s_rx_win_ctrl(fbs.req.band_arfcn, L1_RXWIN_FB);
 380         tpu_end_scenario();
 381
 382         return 0;
 383 }
 384
 385 #if 0
 386 #define FB0_SNR_THRESH  2000
 387 #define FB1_SNR_THRESH  3000
 388 #else
 389 #define FB0_SNR_THRESH  0
 390 #define FB1_SNR_THRESH  0
 391 #endif
 392
 393 static const struct tdma_sched_item fb_sched_set[];
 394
 395 /* scheduler callback to check for a FB detection response */
 396 static int l1s_fbdet_resp(__unused uint8_t p1, uint8_t attempt,
 397                           uint16_t fb_mode)
 398 {
 399         putchart('f');
 400
 401         if (!dsp_api.ndb->d_fb_det) {
 402                 /* we did not detect a FB */
 403
 404                 /* attempt < 12, do nothing */
 405                 if (attempt < 12)
 406                         return 0;
 407
 408                 /* attempt >= 12, we simply don't find one */
 409
 410                 /* If we don't reset here, we get DSP DMA errors */
 411                 tdma_sched_reset();
 412
 413                 if (fbs.fb_retries < FB0_RETRY_COUNT) {
 414                         /* retry once more */
 415                         tdma_schedule_set(1, fb_sched_set, 0);
 416                         fbs.fb_retries++;
 417                 } else {
 418                         last_fb->attempt = 13;
 419                         l1s_compl_sched(L1_COMPL_FB);
 420                 }
 421
 422                 return 0;
 423         }
 424
 425         /* We found a frequency burst, reset everything */
 426         l1s_reset_hw();
 427
 428         printf("FB%u ", dsp_api.ndb->d_fb_mode);
 429         read_fb_result(last_fb, attempt);
 430
 431         /* if this is the first success, save freq err */
 432         if (!fbs.initial_freq_err)
 433                 fbs.initial_freq_err = last_fb->freq_diff;
 434
 435         /* If we don't reset here, we get DSP DMA errors */
 436         tdma_sched_reset();
 437
 438         /* Immediately schedule further TDMA tasklets, if requested. Doing
 439          * this directly from L1S means we can do this quickly without any
 440          * additional delays */
 441         if (fb_mode == 0) {
 442                 if (fbs.req.flags & L1CTL_FBSB_F_FB1) {
 443                         /* If we don't reset here, we get DSP DMA errors */
 444                         tdma_sched_reset();
 445                         /* FIXME: don't only use the last but an average */
 446                         if (abs(last_fb->freq_diff) < fbs.req.freq_err_thresh1 &&
 447                             last_fb->snr > FB0_SNR_THRESH) {
 448                                 /* continue with FB1 task in DSP */
 449                                 tdma_schedule_set(1, fb_sched_set, 1);
 450                         } else {
 451                                 if (fbs.afc_retries < AFC_RETRY_COUNT) {
 452                                         tdma_schedule_set(1, fb_sched_set, 0);
 453                                         fbs.afc_retries++;
 454                                 } else {
 455                                         /* Abort */
 456                                         last_fb->attempt = 13;
 457                                         l1s_compl_sched(L1_COMPL_FB);
 458                                 }
 459                         }
 460                 } else
 461                         l1s_compl_sched(L1_COMPL_FB);
 462         } else if (fb_mode == 1) {
 463                 if (fbs.req.flags & L1CTL_FBSB_F_SB) {
 464
 465         int ntdma, qbits;
 466         /* FIXME: where did this magic 23 come from? */
 467         last_fb->toa -= 23;
 468
 469         if (last_fb->toa < 0) {
 470                 qbits = (last_fb->toa + BITS_PER_TDMA) * 4;
 471                 ntdma = -1;
 472         } else {
 473                 ntdma = (last_fb->toa) / BITS_PER_TDMA;
 474                 qbits = (last_fb->toa - ntdma * BITS_PER_TDMA) * 4;
 475         }
 476
 477
 478                         int fn_offset = l1s.current_time.fn - last_fb->attempt + ntdma;
 479                         int delay = fn_offset + 11 - l1s.current_time.fn - 1;
 480                         printf("  fn_offset=%d (fn=%u + attempt=%u + ntdma = %d)\m",
 481                                 fn_offset, l1s.current_time.fn, last_fb->attempt, ntdma);
 482                         printf("  delay=%d (fn_offset=%d + 11 - fn=%u - 1\n", delay,
 483                                 fn_offset, l1s.current_time.fn);
 484                         printf("  scheduling next FB/SB detection task with delay %u\n", delay);
 485                         if (abs(last_fb->freq_diff) < fbs.req.freq_err_thresh2 &&
 486                             last_fb->snr > FB1_SNR_THRESH) {
 487                                 /* synchronize before reading SB */
 488                                 fbinfo2cellinfo(&l1s.serving_cell, last_fb);
 489                                 synchronize_tdma(&l1s.serving_cell);
 490                                 tdma_schedule_set(delay, sb_sched_set, 0);
 491                         } else
 492                                 tdma_schedule_set(delay, fb_sched_set, 1);
 493                 } else
 494                         l1s_compl_sched(L1_COMPL_FB);
 495         }
 496
 497         return 0;
 498 }
 499
 500 /* FB detection */
 501 static const struct tdma_sched_item fb_sched_set[] = {
 502         SCHED_ITEM(l1s_fbdet_cmd, 0, 0),        SCHED_END_FRAME(),
 503                                                 SCHED_END_FRAME(),
 504         SCHED_ITEM(l1s_fbdet_resp, 0, 1),       SCHED_END_FRAME(),
 505         SCHED_ITEM(l1s_fbdet_resp, 0, 2),       SCHED_END_FRAME(),
 506         SCHED_ITEM(l1s_fbdet_resp, 0, 3),       SCHED_END_FRAME(),
 507         SCHED_ITEM(l1s_fbdet_resp, 0, 4),       SCHED_END_FRAME(),
 508         SCHED_ITEM(l1s_fbdet_resp, 0, 5),       SCHED_END_FRAME(),
 509         SCHED_ITEM(l1s_fbdet_resp, 0, 6),       SCHED_END_FRAME(),
 510         SCHED_ITEM(l1s_fbdet_resp, 0, 7),       SCHED_END_FRAME(),
 511         SCHED_ITEM(l1s_fbdet_resp, 0, 8),       SCHED_END_FRAME(),
 512         SCHED_ITEM(l1s_fbdet_resp, 0, 9),       SCHED_END_FRAME(),
 513         SCHED_ITEM(l1s_fbdet_resp, 0, 10),      SCHED_END_FRAME(),
 514         SCHED_ITEM(l1s_fbdet_resp, 0, 11),      SCHED_END_FRAME(),
 515         SCHED_ITEM(l1s_fbdet_resp, 0, 12),      SCHED_END_FRAME(),
 516         SCHED_END_SET()
 517 };
 518
 519 /* Asynchronous completion handler for FB detection */
 520 static void l1a_fb_compl(__unused enum l1_compl c)
 521 {
 522         struct l1_cell_info *cinfo = &l1s.serving_cell;
 523
 524         if (last_fb->attempt >= 13) {
 525                 /* FB detection failed, signal this via L1CTL */
 526                 return l1ctl_fbsb_resp(255);
 527         }
 528
 529         /* FIME: use l1s.neigh_cell[fbs.cinfo_idx] */
 530         fbinfo2cellinfo(&l1s.serving_cell, last_fb);
 531
 532         /* send FBSB_RESP success message via L1CTL */
 533         l1ctl_fbsb_resp(0);
 534 }
 535
 536 void l1s_fbsb_req(uint8_t base_fn, struct l1ctl_fbsb_req *req)
 537 {
 538         /* copy + endian convert request data */
 539         fbs.req.band_arfcn = ntohs(req->band_arfcn);
 540         fbs.req.timeout = ntohs(req->timeout);
 541         fbs.req.freq_err_thresh1 = ntohs(req->freq_err_thresh1);
 542         fbs.req.freq_err_thresh2 = ntohs(req->freq_err_thresh2);
 543         fbs.req.num_freqerr_avg = req->num_freqerr_avg;
 544         fbs.req.flags = req->flags;
 545         fbs.req.sync_info_idx = req->sync_info_idx;
 546
 547         /* clear initial frequency error */
 548         fbs.initial_freq_err = 0;
 549         fbs.fb_retries = 0;
 550
 551         /* Make sure we start at a 'center' AFCDAC output value */
 552         afc_reset();
 553
 554         if (fbs.req.flags & L1CTL_FBSB_F_FB0)
 555                 tdma_schedule_set(base_fn, fb_sched_set, 0);
 556         else if (fbs.req.flags & L1CTL_FBSB_F_FB1)
 557                 tdma_schedule_set(base_fn, fb_sched_set, 0);
 558         else if (fbs.req.flags & L1CTL_FBSB_F_SB)
 559                 tdma_schedule_set(base_fn, sb_sched_set, 0);
 560
 561         l1s.completion[L1_COMPL_FB] = &l1a_fb_compl;
 562 }