/* PDCH scheduler * * Copyright (C) 2012 Andreas Eversberg * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include #include #include #include #include #include #include #include #include #include #include #include "pcu_utils.h" extern "C" { #include #include "nacc_fsm.h" } struct tbf_sched_candidates { struct gprs_rlcmac_tbf *ul_ass; struct gprs_rlcmac_tbf *dl_ass; struct gprs_rlcmac_tbf *nacc; struct gprs_rlcmac_ul_tbf *ul_ack; }; static void get_ctrl_msg_tbf_candidates(const struct gprs_rlcmac_pdch *pdch, struct tbf_sched_candidates *tbf_cand) { struct gprs_rlcmac_ul_tbf *ul_tbf; struct gprs_rlcmac_dl_tbf *dl_tbf; struct llist_item *pos; llist_for_each_entry(pos, &pdch->trx->ul_tbfs, list) { ul_tbf = tbf_as_ul_tbf((struct gprs_rlcmac_tbf *)pos->entry); OSMO_ASSERT(ul_tbf); if (tbf_ul_ack_rts(ul_tbf, pdch)) tbf_cand->ul_ack = ul_tbf; if (tbf_dl_ass_rts(ul_tbf, pdch)) tbf_cand->dl_ass = ul_tbf; if (tbf_ul_ass_rts(ul_tbf, pdch)) tbf_cand->ul_ass = ul_tbf; if (tbf_nacc_rts(ul_tbf, pdch)) tbf_cand->nacc = ul_tbf; /* FIXME: Is this supposed to be fair? The last TBF for each wins? Maybe use llist_add_tail and skip once we have all states? */ } llist_for_each_entry(pos, &pdch->trx->dl_tbfs, list) { dl_tbf = tbf_as_dl_tbf((struct gprs_rlcmac_tbf *)pos->entry); OSMO_ASSERT(dl_tbf); if (tbf_dl_ass_rts(dl_tbf, pdch)) tbf_cand->dl_ass = dl_tbf; if (tbf_ul_ass_rts(dl_tbf, pdch)) tbf_cand->ul_ass = dl_tbf; if (tbf_nacc_rts(dl_tbf, pdch)) tbf_cand->nacc = dl_tbf; } } static struct gprs_rlcmac_ul_tbf *sched_select_uplink(struct gprs_rlcmac_pdch *pdch, bool require_gprs_only) { struct gprs_rlcmac_ul_tbf *tbf; uint8_t i, tfi; /* select uplink resource */ for (i = 0, tfi = pdch->next_ul_tfi; i < 32; i++, tfi = (tfi + 1) & 31) { tbf = pdch->ul_tbf_by_tfi(tfi); /* no TBF for this tfi, go next */ if (!tbf) continue; /* no UL resources needed, go next */ /* we don't need to give resources in FINISHED state, * because we have received all blocks and only poll * for packet control ack. */ if (tbf->state_is_not(TBF_ST_FLOW)) continue; if (require_gprs_only && tbf->is_egprs_enabled()) continue; /* use this USF (tbf) */ /* next TBF to handle resource is the next one */ pdch->next_ul_tfi = (tfi + 1) & 31; return tbf; } return NULL; } struct msgb *sched_app_info(struct gprs_rlcmac_tbf *tbf) { struct gprs_rlcmac_bts *bts; struct msgb *msg = NULL; if (!tbf || !tbf->ms()->app_info_pending) return NULL; bts = tbf->bts; if (bts->app_info) { LOGP(DRLCMACSCHED, LOGL_DEBUG, "Sending Packet Application Information message\n"); msg = msgb_copy(bts->app_info, "app_info_msg_sched"); } else LOGP(DRLCMACSCHED, LOGL_ERROR, "MS has app_info_pending flag set, but no Packet Application Information" " message stored in BTS!\n"); tbf->ms()->app_info_pending = false; bts->app_info_pending--; if (!bts->app_info_pending) { LOGP(DRLCMACSCHED, LOGL_DEBUG, "Packet Application Information successfully sent to all MS with active" " TBF\n"); msgb_free(bts->app_info); bts->app_info = NULL; } return msg; } static struct msgb *sched_select_ctrl_msg(struct gprs_rlcmac_pdch *pdch, uint32_t fn, uint8_t block_nr, struct tbf_sched_candidates *tbfs) { struct msgb *msg = NULL; struct gprs_rlcmac_tbf *tbf = NULL; struct gprs_rlcmac_tbf *next_list[] = { tbfs->ul_ass, tbfs->dl_ass, tbfs->ul_ack, tbfs->nacc }; /* Send Packet Application Information first (ETWS primary notifications) */ msg = sched_app_info(tbfs->dl_ass); if (!msg) { for (size_t i = 0; i < ARRAY_SIZE(next_list); ++i) { tbf = next_list[(pdch->next_ctrl_prio + i) % ARRAY_SIZE(next_list)]; if (!tbf) continue; /* * Assignments for the same direction have lower precedence, * because they may kill the TBF when the CONTROL ACK is * received, thus preventing the others from being processed. */ if (tbf == tbfs->ul_ass && tbf->ul_ass_state_is(TBF_UL_ASS_SEND_ASS_REJ)) msg = tbf_ul_ass_create_rlcmac_msg(tbfs->ul_ass, pdch, fn); else if (tbf == tbfs->ul_ass && tbf->direction == GPRS_RLCMAC_DL_TBF) msg = tbf_ul_ass_create_rlcmac_msg(tbfs->ul_ass, pdch, fn); else if (tbf == tbfs->dl_ass && tbf->direction == GPRS_RLCMAC_UL_TBF) msg = tbf_dl_ass_create_rlcmac_msg(tbfs->dl_ass, pdch, fn); else if (tbf == tbfs->ul_ack) msg = tbf_ul_ack_create_rlcmac_msg(tbfs->ul_ack, pdch, fn); else if (tbf == tbfs->nacc) msg = ms_nacc_create_rlcmac_msg(tbf->ms(), tbf, pdch, fn); if (!msg) { tbf = NULL; continue; } pdch->next_ctrl_prio = (pdch->next_ctrl_prio + 1) % ARRAY_SIZE(next_list); break; } } if (!msg) { /* * If one of these is left, the response (CONTROL ACK) from the * MS will kill the current TBF, only one of them can be * non-NULL */ if (tbfs->dl_ass) { tbf = tbfs->dl_ass; msg = tbf_dl_ass_create_rlcmac_msg(tbfs->dl_ass, pdch, fn); } else if (tbfs->ul_ass) { tbf = tbfs->ul_ass; msg = tbf_ul_ass_create_rlcmac_msg(tbfs->ul_ass, pdch, fn); } } /* any message */ if (msg) { if (!tbf) { LOGPDCH(pdch, DRLCMACSCHED, LOGL_ERROR, "FN=%" PRIu32 " Control message to be scheduled, but no TBF\n", fn); msgb_free(msg); return NULL; } tbf->rotate_in_list(); LOGPDCH(pdch, DRLCMACSCHED, LOGL_DEBUG, "FN=%" PRIu32 " Scheduling control message at RTS for %s\n", fn, tbf_name(tbf)); rate_ctr_inc(rate_ctr_group_get_ctr(tbf->ms()->ctrs, MS_CTR_DL_CTRL_MSG_SCHED)); return msg; } /* schedule PACKET PAGING REQUEST, if any are pending */ msg = pdch->packet_paging_request(); if (msg) { LOGPDCH(pdch, DRLCMACSCHED, LOGL_DEBUG, "FN=%" PRIu32 " Scheduling paging request message at RTS\n", fn); return msg; } return NULL; } static inline enum tbf_dl_prio tbf_compute_priority(const struct gprs_rlcmac_bts *bts, struct gprs_rlcmac_dl_tbf *tbf, const struct gprs_rlcmac_pdch *pdch, uint32_t fn, int age) { const gprs_rlc_dl_window *w = static_cast(tbf->window()); unsigned long msecs_t3190 = osmo_tdef_get(the_pcu->T_defs, 3190, OSMO_TDEF_MS, -1); unsigned long dl_tbf_idle_msec = osmo_tdef_get(the_pcu->T_defs, -2031, OSMO_TDEF_MS, -1); int age_thresh1 = msecs_to_frames(200); int age_thresh2 = msecs_to_frames(OSMO_MIN(msecs_t3190/2, dl_tbf_idle_msec)); const bool is_control_ts = tbf_is_control_ts(tbf, pdch); if (is_control_ts && tbf->need_poll_for_dl_ack_nack()) return DL_PRIO_CONTROL; if (is_control_ts && age > age_thresh2 && age_thresh2 > 0) return DL_PRIO_HIGH_AGE; if ((tbf->state_is(TBF_ST_FLOW) && tbf->have_data()) || w->resend_needed() >= 0) return DL_PRIO_NEW_DATA; if (is_control_ts && age > age_thresh1 && tbf->keep_open(fn)) return DL_PRIO_LOW_AGE; if (!w->window_empty()) return DL_PRIO_SENT_DATA; return DL_PRIO_NONE; } /* Check if next data block of a TBF can be encoded in GMSK [(M)CS1-4]. */ static bool can_produce_gmsk_data_block_next(struct gprs_rlcmac_dl_tbf *tbf, enum tbf_dl_prio prio) { const gprs_rlc_dl_window *w; /* GPRS TBFs can always send GMSK */ if (!tbf->is_egprs_enabled()) return true; switch (prio) { case DL_PRIO_CONTROL: /* Control blocks are always CS-1 */ return true; case DL_PRIO_NEW_DATA: /* We can send any new data (no block generated yet) using any * MCS. However, we don't (yet) support resegmenting already * sent blocks (NACKed blocks in this case) into lower MCS of * the same family. See OS#4966 */ w = static_cast(tbf->window()); return w->resend_needed() < 0; default: return false; } } static struct msgb *sched_select_dl_data_msg(struct gprs_rlcmac_bts *bts, struct gprs_rlcmac_pdch *pdch, uint32_t fn, uint8_t block_nr, enum mcs_kind req_mcs_kind, bool *is_egprs) { struct msgb *msg = NULL; struct gprs_rlcmac_dl_tbf *tbf, *prio_tbf = NULL; enum tbf_dl_prio prio, max_prio = DL_PRIO_NONE; uint8_t i, tfi, prio_tfi; int age; /* select downlink resource */ for (i = 0, tfi = pdch->next_dl_tfi; i < 32; i++, tfi = (tfi + 1) & 31) { tbf = pdch->dl_tbf_by_tfi(tfi); /* no TBF for this tfi, go next */ if (!tbf) continue; /* no DL TBF, go next */ if (tbf->direction != GPRS_RLCMAC_DL_TBF) continue; /* no DL resources needed, go next */ if (tbf->state_is_not(TBF_ST_FLOW) && tbf->state_is_not(TBF_ST_FINISHED)) continue; /* If a GPRS (CS1-4) Dl block is required, skip EGPRS(_GSMK) tbfs: */ if (req_mcs_kind == GPRS && tbf->is_egprs_enabled()) continue; age = tbf->frames_since_last_poll(fn); /* compute priority */ prio = tbf_compute_priority(bts, tbf, pdch, fn, age); if (prio == DL_PRIO_NONE) continue; /* If a GPRS (CS1-4/MCS1-4) Dl block is required, downgrade MCS * below instead of skipping. However, downgrade can only be * done on new data BSNs (not yet sent) and control blocks. */ if (req_mcs_kind == EGPRS_GMSK && !can_produce_gmsk_data_block_next(tbf, prio)) { LOGPDCH(pdch, DRLCMACSCHED, LOGL_DEBUG, "FN=%" PRIu32 " Cannot downgrade EGPRS TBF with prio %d for %s\n", fn, prio, tbf_name(tbf)); continue; } /* get the TBF with the highest priority */ if (prio > max_prio) { prio_tfi = tfi; prio_tbf = tbf; max_prio = prio; } } if (prio_tbf) { LOGPDCH(pdch, DRLCMACSCHED, LOGL_DEBUG, "FN=%" PRIu32 " Scheduling data message at RTS for DL TFI=%d prio=%d mcs_mode_restrict=%s\n", fn, prio_tfi, max_prio, mode_name(req_mcs_kind)); /* next TBF to handle resource is the next one */ pdch->next_dl_tfi = (prio_tfi + 1) & 31; /* generate DL data block */ msg = prio_tbf->create_dl_acked_block(fn, pdch, req_mcs_kind); *is_egprs = prio_tbf->is_egprs_enabled(); } return msg; } static const uint8_t rlcmac_dl_idle[23] = { 0x47, /* control without optional header octets, no polling, USF=111 */ 0x94, /* dummy downlink control message, paging mode 00 */ 0x2b, /* no persistance level, 7 bits spare pattern */ 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b }; static struct msgb *sched_dummy(void) { struct msgb *msg; msg = msgb_alloc(23, "rlcmac_dl_idle"); if (!msg) return NULL; memcpy(msgb_put(msg, 23), rlcmac_dl_idle, 23); return msg; } static inline void tap_n_acc(const struct msgb *msg, struct gprs_rlcmac_bts *bts, uint8_t trx, uint8_t ts, uint32_t fn, enum pcu_gsmtap_category cat) { if (!msg) return; switch(cat) { case PCU_GSMTAP_C_DL_CTRL: bts_do_rate_ctr_inc(bts, CTR_RLC_SENT_CONTROL); bts_send_gsmtap(bts, PCU_GSMTAP_C_DL_CTRL, false, trx, ts, GSMTAP_CHANNEL_PACCH, fn, msg->data, msg->len); break; case PCU_GSMTAP_C_DL_DATA_GPRS: case PCU_GSMTAP_C_DL_DATA_EGPRS: bts_do_rate_ctr_inc(bts, CTR_RLC_SENT); bts_send_gsmtap(bts, cat, false, trx, ts, GSMTAP_CHANNEL_PDTCH, fn, msg->data, msg->len); break; case PCU_GSMTAP_C_DL_DUMMY: bts_do_rate_ctr_inc(bts, CTR_RLC_SENT_DUMMY); bts_send_gsmtap(bts, PCU_GSMTAP_C_DL_DUMMY, false, trx, ts, GSMTAP_CHANNEL_PACCH, fn, msg->data, msg->len); break; default: break; } } int gprs_rlcmac_rcv_rts_block(struct gprs_rlcmac_bts *bts, uint8_t trx, uint8_t ts, uint32_t fn, uint8_t block_nr) { struct gprs_rlcmac_pdch *pdch; struct tbf_sched_candidates tbf_cand = {0}; struct gprs_rlcmac_tbf *poll_tbf; struct gprs_rlcmac_ul_tbf *usf_tbf = NULL; struct gprs_rlcmac_sba *sba; uint8_t usf; struct msgb *msg = NULL; uint32_t poll_fn; enum pcu_gsmtap_category gsmtap_cat = PCU_GSMTAP_C_DL_DUMMY; /* init: make gcc happy */ bool tx_is_egprs = false; bool require_gprs_only; enum mcs_kind req_mcs_kind; /* Restrict CS/MCS if DL Data block is to be sent */ if (trx >= 8 || ts >= 8) return -EINVAL; pdch = &bts->trx[trx].pdch[ts]; if (!pdch->is_enabled()) { LOGPDCH(pdch, DRLCMACSCHED, LOGL_INFO, "Received RTS on disabled TS\n"); return -EIO; } /* store last frame number of RTS */ pdch->last_rts_fn = fn; /* require_gprs_only: Prioritize USF for GPRS-only MS here, * since anyway we'll need to tx a Dl block with CS1-4 due to * synchronization requirements. See 3GPP TS 03.64 version * 8.12.0 */ require_gprs_only = (pdch->fn_without_cs14 == MS_RESYNC_NUM_FRAMES - 1); if (require_gprs_only) { LOGP(DRLCMACSCHED, LOGL_DEBUG, "TRX=%d TS=%d FN=%d " "synchronization frame (every 18 frames), only CS1-4 allowed", trx, ts, fn); req_mcs_kind = GPRS; /* only GPRS CS1-4 allowed, all MS need to be able to decode it */ } else { req_mcs_kind = EGPRS; /* all kinds are fine */ } /* polling for next uplink block */ poll_fn = rts_next_fn(fn, block_nr); /* check for sba */ if ((sba = pdch_ulc_get_sba(pdch->ulc, poll_fn))) { LOGPDCH(pdch, DRLCMACSCHED, LOGL_DEBUG, "Received RTS for PDCH: " "FN=%d block_nr=%d scheduling free USF for " "single block allocation at FN=%d\n", fn, block_nr, sba->fn); /* else, check uplink resource for polling */ } else if ((poll_tbf = pdch_ulc_get_tbf_poll(pdch->ulc, poll_fn))) { LOGPDCH(pdch, DRLCMACSCHED, LOGL_DEBUG, "Received RTS for PDCH: FN=%d " "block_nr=%d scheduling free USF for polling at FN=%d of %s\n", fn, block_nr, poll_fn, tbf_name(poll_tbf)); /* If POLL TBF is UL and already has a USF assigned on this TS, * let's set its USF in the DL msg. This is not really needed, * but it helps understand better the flow when looking at * pcaps. */ if (poll_tbf->direction == GPRS_RLCMAC_UL_TBF && tbf_as_ul_tbf(poll_tbf)->m_usf[ts] != USF_INVALID) usf_tbf = tbf_as_ul_tbf(poll_tbf); /* else, search for uplink tbf */ } else if ((usf_tbf = sched_select_uplink(pdch, require_gprs_only))) { LOGPDCH(pdch, DRLCMACSCHED, LOGL_DEBUG, "Received RTS for PDCH: FN=%d " "block_nr=%d scheduling USF=%d for %s, expect answer on UL FN=%d\n", fn, block_nr, usf_tbf->m_usf[pdch->ts_no], tbf_name(usf_tbf), poll_fn); pdch_ulc_reserve_tbf_usf(pdch->ulc, poll_fn, usf_tbf); } /* If MS selected for USF is GPRS-only, then it will only be * able to read USF if dl block uses GMSK (CS1-4, MCS1-4) */ if (usf_tbf && req_mcs_kind == EGPRS && ms_mode(usf_tbf->ms()) != EGPRS) req_mcs_kind = EGPRS_GMSK; get_ctrl_msg_tbf_candidates(pdch, &tbf_cand); /* Prio 1: select control message */ if ((msg = sched_select_ctrl_msg(pdch, fn, block_nr, &tbf_cand))) { gsmtap_cat = PCU_GSMTAP_C_DL_CTRL; } /* Prio 2: select data message for downlink */ else if((msg = sched_select_dl_data_msg(bts, pdch, fn, block_nr, req_mcs_kind, &tx_is_egprs))) { gsmtap_cat = tx_is_egprs ? PCU_GSMTAP_C_DL_DATA_EGPRS : PCU_GSMTAP_C_DL_DATA_GPRS; } /* Prio 3: send dummy control message if need to poll or USF */ else { /* If there's no TBF attached to this PDCH, we can submit an empty * data_req since there's nothing to transmit nor to poll/USF. This * way we help BTS energy saving (on TRX!=C0) by sending nothing * instead of a dummy block. The early return is done here and * not at the start of the function because the condition below * (num_tbfs==0) may not be enough, because temporary dummy TBFs * created to send Imm Ass Rej (see handle_tbf_reject()) don't * have a TFI assigned and hence are not attached to the PDCH * TS, so they don't show up in the count below. */ const unsigned num_tbfs = pdch->num_tbfs(GPRS_RLCMAC_DL_TBF) + pdch->num_tbfs(GPRS_RLCMAC_UL_TBF); bool skip_idle = (num_tbfs == 0); if (bts->gen_idle_blocks_C0) skip_idle = skip_idle && trx != 0; if (!skip_idle && (msg = sched_dummy())) { /* increase counter */ gsmtap_cat = PCU_GSMTAP_C_DL_DUMMY; } else { msg = NULL; /* submit empty frame */ } } if (tx_is_egprs && pdch->has_gprs_only_tbf_attached()) { pdch->fn_without_cs14 += 1; } else { pdch->fn_without_cs14 = 0; } /* Used to measure the leak rate, count all blocks */ gprs_bssgp_update_frames_sent(); if (msg) { /* msg is now available */ bts_do_rate_ctr_add(bts, CTR_RLC_DL_BYTES, msgb_length(msg)); /* set USF */ OSMO_ASSERT(msgb_length(msg) > 0); usf = usf_tbf ? usf_tbf->m_usf[ts] : USF_UNUSED; msg->data[0] = (msg->data[0] & 0xf8) | usf; /* Send to GSMTAP */ tap_n_acc(msg, bts, trx, ts, fn, gsmtap_cat); } /* send PDTCH/PACCH to L1. msg=NULL accepted too (idle block) */ pcu_l1if_tx_pdtch(msg, bts, trx, ts, bts->trx[trx].arfcn, fn, block_nr); return 0; }