393 lines
11 KiB
C++
393 lines
11 KiB
C++
/* PDCH scheduler
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*
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* Copyright (C) 2012 Andreas Eversberg <jolly@eversberg.eu>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include <gprs_bssgp_pcu.h>
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#include <gprs_rlcmac.h>
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#include <pcu_l1_if.h>
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#include <bts.h>
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#include <tbf.h>
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#include "pcu_utils.h"
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static uint32_t sched_poll(BTS *bts,
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uint8_t trx, uint8_t ts, uint32_t fn, uint8_t block_nr,
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struct gprs_rlcmac_tbf **poll_tbf,
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struct gprs_rlcmac_tbf **ul_ass_tbf,
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struct gprs_rlcmac_tbf **dl_ass_tbf,
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struct gprs_rlcmac_ul_tbf **ul_ack_tbf)
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{
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struct gprs_rlcmac_ul_tbf *ul_tbf;
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struct gprs_rlcmac_dl_tbf *dl_tbf;
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LListHead<gprs_rlcmac_tbf> *pos;
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uint32_t poll_fn;
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/* check special TBF for events */
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poll_fn = fn + 4;
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if ((block_nr % 3) == 2)
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poll_fn ++;
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poll_fn = poll_fn % 2715648;
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llist_for_each(pos, &bts->ul_tbfs()) {
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ul_tbf = as_ul_tbf(pos->entry());
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OSMO_ASSERT(ul_tbf);
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/* this trx, this ts */
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if (ul_tbf->trx->trx_no != trx || !ul_tbf->is_control_ts(ts))
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continue;
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/* polling for next uplink block */
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if (ul_tbf->poll_state == GPRS_RLCMAC_POLL_SCHED
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&& ul_tbf->poll_fn == poll_fn)
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*poll_tbf = ul_tbf;
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if (ul_tbf->ul_ack_state == GPRS_RLCMAC_UL_ACK_SEND_ACK)
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*ul_ack_tbf = ul_tbf;
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if (ul_tbf->dl_ass_state == GPRS_RLCMAC_DL_ASS_SEND_ASS)
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*dl_ass_tbf = ul_tbf;
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if (ul_tbf->ul_ass_state == GPRS_RLCMAC_UL_ASS_SEND_ASS
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|| ul_tbf->ul_ass_state ==
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GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ)
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*ul_ass_tbf = ul_tbf;
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#warning "Is this supposed to be fair? The last TBF for each wins? Maybe use llist_add_tail and skip once we have all states?"
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}
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llist_for_each(pos, &bts->dl_tbfs()) {
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dl_tbf = as_dl_tbf(pos->entry());
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OSMO_ASSERT(dl_tbf);
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/* this trx, this ts */
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if (dl_tbf->trx->trx_no != trx || !dl_tbf->is_control_ts(ts))
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continue;
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/* polling for next uplink block */
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if (dl_tbf->poll_state == GPRS_RLCMAC_POLL_SCHED
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&& dl_tbf->poll_fn == poll_fn)
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*poll_tbf = dl_tbf;
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if (dl_tbf->dl_ass_state == GPRS_RLCMAC_DL_ASS_SEND_ASS)
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*dl_ass_tbf = dl_tbf;
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if (dl_tbf->ul_ass_state == GPRS_RLCMAC_UL_ASS_SEND_ASS
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|| dl_tbf->ul_ass_state == GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ)
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*ul_ass_tbf = dl_tbf;
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}
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return poll_fn;
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}
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static uint8_t sched_select_uplink(uint8_t trx, uint8_t ts, uint32_t fn,
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uint8_t block_nr, struct gprs_rlcmac_pdch *pdch)
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{
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struct gprs_rlcmac_ul_tbf *tbf;
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uint8_t usf = 0x07;
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uint8_t i, tfi;
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/* select uplink resource */
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for (i = 0, tfi = pdch->next_ul_tfi; i < 32;
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i++, tfi = (tfi + 1) & 31) {
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tbf = pdch->ul_tbf_by_tfi(tfi);
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/* no TBF for this tfi, go next */
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if (!tbf)
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continue;
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/* no UL resources needed, go next */
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/* we don't need to give resources in FINISHED state,
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* because we have received all blocks and only poll
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* for packet control ack. */
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if (tbf->state_is_not(GPRS_RLCMAC_FLOW))
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continue;
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/* use this USF */
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usf = tbf->m_usf[ts];
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LOGP(DRLCMACSCHED, LOGL_DEBUG, "Received RTS for PDCH: TRX=%d "
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"TS=%d FN=%d block_nr=%d scheduling USF=%d for "
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"required uplink resource of UL TFI=%d\n", trx, ts, fn,
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block_nr, usf, tfi);
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/* next TBF to handle resource is the next one */
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pdch->next_ul_tfi = (tfi + 1) & 31;
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break;
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}
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return usf;
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}
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static struct msgb *sched_select_ctrl_msg(
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uint8_t trx, uint8_t ts, uint32_t fn,
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uint8_t block_nr, struct gprs_rlcmac_pdch *pdch,
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struct gprs_rlcmac_tbf *ul_ass_tbf,
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struct gprs_rlcmac_tbf *dl_ass_tbf,
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struct gprs_rlcmac_ul_tbf *ul_ack_tbf)
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{
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struct msgb *msg = NULL;
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struct gprs_rlcmac_tbf *tbf = NULL;
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struct gprs_rlcmac_tbf *next_list[3] = { ul_ass_tbf, dl_ass_tbf, ul_ack_tbf };
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for (size_t i = 0; i < ARRAY_SIZE(next_list); ++i) {
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tbf = next_list[(pdch->next_ctrl_prio + i) % 3];
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if (!tbf)
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continue;
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/*
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* Assignments for the same direction have lower precedence,
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* because they may kill the TBF when the CONTROL ACK is
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* received, thus preventing the others from being processed.
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*/
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if (tbf == ul_ass_tbf && tbf->ul_ass_state ==
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GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ)
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msg = ul_ass_tbf->create_packet_access_reject();
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else if (tbf == ul_ass_tbf && tbf->direction ==
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GPRS_RLCMAC_DL_TBF)
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if (tbf->ul_ass_state ==
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GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ)
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msg = ul_ass_tbf->create_packet_access_reject();
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else
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msg = ul_ass_tbf->create_ul_ass(fn, ts);
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else if (tbf == dl_ass_tbf && tbf->direction == GPRS_RLCMAC_UL_TBF)
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msg = dl_ass_tbf->create_dl_ass(fn, ts);
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else if (tbf == ul_ack_tbf)
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msg = ul_ack_tbf->create_ul_ack(fn, ts);
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if (!msg) {
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tbf = NULL;
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continue;
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}
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pdch->next_ctrl_prio += 1;
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pdch->next_ctrl_prio %= 3;
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break;
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}
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if (!msg) {
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/*
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* If one of these is left, the response (CONTROL ACK) from the
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* MS will kill the current TBF, only one of them can be
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* non-NULL
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*/
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if (dl_ass_tbf) {
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tbf = dl_ass_tbf;
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msg = dl_ass_tbf->create_dl_ass(fn, ts);
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} else if (ul_ass_tbf) {
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tbf = ul_ass_tbf;
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msg = ul_ass_tbf->create_ul_ass(fn, ts);
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}
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}
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if (!tbf)
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return NULL;
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/* any message */
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if (msg) {
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tbf->rotate_in_list();
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LOGP(DRLCMACSCHED, LOGL_DEBUG, "Scheduling control "
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"message at RTS for %s (TRX=%d, TS=%d)\n",
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tbf_name(tbf), trx, ts);
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/* Updates the dl ctrl msg counter for ms */
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tbf->ms()->update_dl_ctrl_msg();
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return msg;
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}
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/* schedule PACKET PAGING REQUEST */
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msg = pdch->packet_paging_request();
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if (msg) {
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LOGP(DRLCMACSCHED, LOGL_DEBUG, "Scheduling paging request "
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"message at RTS for (TRX=%d, TS=%d)\n", trx, ts);
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/* Updates the dl ctrl msg counter for ms */
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tbf->ms()->update_dl_ctrl_msg();
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return msg;
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}
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return NULL;
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}
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static struct msgb *sched_select_downlink(struct gprs_rlcmac_bts *bts,
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uint8_t trx, uint8_t ts, uint32_t fn,
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uint8_t block_nr, struct gprs_rlcmac_pdch *pdch)
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{
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struct msgb *msg = NULL;
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struct gprs_rlcmac_dl_tbf *tbf, *prio_tbf = NULL;
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enum {
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DL_PRIO_NONE,
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DL_PRIO_SENT_DATA, /* the data has been sent and not (yet) nacked */
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DL_PRIO_LOW_AGE, /* the age has reached the first threshold */
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DL_PRIO_NEW_DATA, /* the data has not been sent yet or nacked */
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DL_PRIO_HIGH_AGE, /* the age has reached the second threshold */
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DL_PRIO_CONTROL, /* a control block needs to be sent */
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} prio, max_prio = DL_PRIO_NONE;
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uint8_t i, tfi, prio_tfi;
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int age;
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const int age_thresh1 = msecs_to_frames(200);
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const int high_prio_msecs =
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OSMO_MIN(BTS::TIMER_T3190_MSEC/2, bts->dl_tbf_idle_msec);
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const int age_thresh2 = msecs_to_frames(high_prio_msecs);
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/* select downlink resource */
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for (i = 0, tfi = pdch->next_dl_tfi; i < 32;
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i++, tfi = (tfi + 1) & 31) {
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tbf = pdch->dl_tbf_by_tfi(tfi);
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/* no TBF for this tfi, go next */
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if (!tbf)
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continue;
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/* no DL TBF, go next */
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if (tbf->direction != GPRS_RLCMAC_DL_TBF)
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continue;
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/* no DL resources needed, go next */
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if (tbf->state_is_not(GPRS_RLCMAC_FLOW)
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&& tbf->state_is_not(GPRS_RLCMAC_FINISHED))
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continue;
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/* waiting for CCCH IMM.ASS confirm */
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if (tbf->m_wait_confirm)
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continue;
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age = tbf->frames_since_last_poll(fn);
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/* compute priority */
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if (tbf->is_control_ts(ts) && tbf->need_control_ts())
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prio = DL_PRIO_CONTROL;
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else if (tbf->is_control_ts(ts) &&
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age > age_thresh2 && age_thresh2 > 0)
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prio = DL_PRIO_HIGH_AGE;
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else if ((tbf->state_is(GPRS_RLCMAC_FLOW) && tbf->have_data()) ||
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tbf->m_window.resend_needed() >= 0)
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prio = DL_PRIO_NEW_DATA;
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else if (tbf->is_control_ts(ts) &&
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age > age_thresh1 && tbf->keep_open(fn))
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prio = DL_PRIO_LOW_AGE;
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else if (!tbf->m_window.window_empty())
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prio = DL_PRIO_SENT_DATA;
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else
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continue;
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/* get the TBF with the highest priority */
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if (prio > max_prio) {
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prio_tfi = tfi;
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prio_tbf = tbf;
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max_prio = prio;
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}
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}
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if (prio_tbf) {
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LOGP(DRLCMACSCHED, LOGL_DEBUG, "Scheduling data message at "
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"RTS for DL TFI=%d (TRX=%d, TS=%d) prio=%d\n",
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prio_tfi, trx, ts, max_prio);
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/* next TBF to handle resource is the next one */
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pdch->next_dl_tfi = (prio_tfi + 1) & 31;
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/* generate DL data block */
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msg = prio_tbf->create_dl_acked_block(fn, ts);
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}
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return msg;
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}
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static const uint8_t rlcmac_dl_idle[23] = {
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0x47, /* control without optional header octets, no polling, USF=111 */
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0x94, /* dummy downlink control message, paging mode 00 */
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0x2b, /* no persistance level, 7 bits spare pattern */
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0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b,
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0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b
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};
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static struct msgb *sched_dummy(void)
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{
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struct msgb *msg;
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msg = msgb_alloc(23, "rlcmac_dl_idle");
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if (!msg)
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return NULL;
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memcpy(msgb_put(msg, 23), rlcmac_dl_idle, 23);
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return msg;
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}
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int gprs_rlcmac_rcv_rts_block(struct gprs_rlcmac_bts *bts,
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uint8_t trx, uint8_t ts,
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uint32_t fn, uint8_t block_nr)
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{
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struct gprs_rlcmac_pdch *pdch;
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struct gprs_rlcmac_tbf *poll_tbf = NULL, *dl_ass_tbf = NULL,
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*ul_ass_tbf = NULL;
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struct gprs_rlcmac_ul_tbf *ul_ack_tbf = NULL;
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uint8_t usf = 0x7;
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struct msgb *msg = NULL;
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uint32_t poll_fn, sba_fn;
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if (trx >= 8 || ts >= 8)
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return -EINVAL;
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pdch = &bts->trx[trx].pdch[ts];
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if (!pdch->is_enabled()) {
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LOGP(DRLCMACSCHED, LOGL_ERROR, "Received RTS on disabled PDCH: "
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"TRX=%d TS=%d\n", trx, ts);
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return -EIO;
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}
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/* store last frame number of RTS */
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pdch->last_rts_fn = fn;
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poll_fn = sched_poll(bts->bts, trx, ts, fn, block_nr, &poll_tbf, &ul_ass_tbf,
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&dl_ass_tbf, &ul_ack_tbf);
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/* check uplink resource for polling */
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if (poll_tbf)
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LOGP(DRLCMACSCHED, LOGL_DEBUG, "Received RTS for PDCH: TRX=%d "
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"TS=%d FN=%d block_nr=%d scheduling free USF for "
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"polling at FN=%d of %s\n", trx, ts, fn,
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block_nr, poll_fn,
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tbf_name(poll_tbf));
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/* use free USF */
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/* else. check for sba */
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else if ((sba_fn = bts->bts->sba()->sched(trx, ts, fn, block_nr) != 0xffffffff))
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LOGP(DRLCMACSCHED, LOGL_DEBUG, "Received RTS for PDCH: TRX=%d "
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"TS=%d FN=%d block_nr=%d scheduling free USF for "
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"single block allocation at FN=%d\n", trx, ts, fn,
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block_nr, sba_fn);
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/* use free USF */
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/* else, we search for uplink resource */
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else
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usf = sched_select_uplink(trx, ts, fn, block_nr, pdch);
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/* Prio 1: select control message */
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msg = sched_select_ctrl_msg(trx, ts, fn, block_nr, pdch, ul_ass_tbf,
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dl_ass_tbf, ul_ack_tbf);
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if (msg)
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bts->bts->rlc_sent_control();
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/* Prio 2: select data message for downlink */
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if (!msg) {
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msg = sched_select_downlink(bts, trx, ts, fn, block_nr, pdch);
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if (msg)
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bts->bts->rlc_sent();
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}
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/* Prio 3: send dummy contol message */
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if (!msg) {
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/* increase counter */
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msg = sched_dummy();
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if (msg)
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bts->bts->rlc_sent_dummy();
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}
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if (!msg)
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return -ENOMEM;
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/* msg is now available */
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bts->bts->rlc_dl_bytes(msg->data_len);
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/* set USF */
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OSMO_ASSERT(msgb_length(msg) > 0);
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msg->data[0] = (msg->data[0] & 0xf8) | usf;
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/* Used to measure the leak rate, count all blocks */
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gprs_bssgp_update_frames_sent();
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/* send PDTCH/PACCH to L1 */
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pcu_l1if_tx_pdtch(msg, trx, ts, bts->trx[trx].arfcn, fn, block_nr);
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return 0;
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}
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