cellular-infrastructure
/
osmo-pcu
mirror of https://gerrit.osmocom.org/osmo-pcu
9
0
Fork 1
Code Issues Releases Wiki Activity
osmo-pcu/src/gprs_rlcmac_sched.cpp

513 lines
16 KiB
C++
Raw Blame History

/* PDCH scheduler
*
* Copyright (C) 2012 Andreas Eversberg <jolly@eversberg.eu>
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <gprs_bssgp_pcu.h>
#include <gprs_rlcmac.h>
#include <pcu_l1_if.h>
#include <bts.h>
#include <tbf.h>
#include <tbf_ul.h>
#include <gprs_debug.h>
#include <gprs_ms.h>
#include <rlc.h>
#include <sba.h>
#include <pdch.h>
#include "pcu_utils.h"
extern "C" {
#include <osmocom/core/gsmtap.h>
}
struct tbf_sched_candidates {
struct gprs_rlcmac_tbf *poll;
struct gprs_rlcmac_tbf *ul_ass;
struct gprs_rlcmac_tbf *dl_ass;
struct gprs_rlcmac_ul_tbf *ul_ack;
};
static uint32_t sched_poll(struct gprs_rlcmac_bts *bts,
uint8_t trx, uint8_t ts, uint32_t fn, uint8_t block_nr,
struct tbf_sched_candidates *tbf_cand)
{
struct gprs_rlcmac_ul_tbf *ul_tbf;
struct gprs_rlcmac_dl_tbf *dl_tbf;
struct llist_item *pos;
uint32_t poll_fn;
/* check special TBF for events */
poll_fn = fn + 4;
if ((block_nr % 3) == 2)
poll_fn ++;
poll_fn = poll_fn % GSM_MAX_FN;
llist_for_each_entry(pos, &bts->ul_tbfs, list) {
ul_tbf = as_ul_tbf((struct gprs_rlcmac_tbf *)pos->entry);
OSMO_ASSERT(ul_tbf);
/* this trx, this ts */
if (ul_tbf->trx->trx_no != trx || !ul_tbf->is_control_ts(ts))
continue;
/* polling for next uplink block */
if (ul_tbf->poll_scheduled() && ul_tbf->poll_fn == poll_fn)
tbf_cand->poll = ul_tbf;
if (ul_tbf->ul_ack_state_is(GPRS_RLCMAC_UL_ACK_SEND_ACK))
tbf_cand->ul_ack = ul_tbf;
if (ul_tbf->dl_ass_state_is(GPRS_RLCMAC_DL_ASS_SEND_ASS))
tbf_cand->dl_ass = ul_tbf;
if (ul_tbf->ul_ass_state_is(GPRS_RLCMAC_UL_ASS_SEND_ASS)
|| ul_tbf->ul_ass_state_is(GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ))
tbf_cand->ul_ass = 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, &bts->dl_tbfs, list) {
dl_tbf = as_dl_tbf((struct gprs_rlcmac_tbf *)pos->entry);
OSMO_ASSERT(dl_tbf);
/* this trx, this ts */
if (dl_tbf->trx->trx_no != trx || !dl_tbf->is_control_ts(ts))
continue;
/* polling for next uplink block */
if (dl_tbf->poll_scheduled() && dl_tbf->poll_fn == poll_fn)
tbf_cand->poll = dl_tbf;
if (dl_tbf->dl_ass_state_is(GPRS_RLCMAC_DL_ASS_SEND_ASS))
tbf_cand->dl_ass = dl_tbf;
if (dl_tbf->ul_ass_state_is(GPRS_RLCMAC_UL_ASS_SEND_ASS)
|| dl_tbf->ul_ass_state_is(GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ))
tbf_cand->ul_ass = dl_tbf;
}
return poll_fn;
}
static struct gprs_rlcmac_ul_tbf *sched_select_uplink(uint8_t trx, uint8_t ts, uint32_t fn,
uint8_t block_nr, struct gprs_rlcmac_pdch *pdch, bool require_gprs_only)
{
struct gprs_rlcmac_ul_tbf *tbf = NULL;
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(GPRS_RLCMAC_FLOW))
continue;
if (require_gprs_only && tbf->is_egprs_enabled())
continue;
/* use this USF */
LOGP(DRLCMACSCHED, LOGL_DEBUG, "Received RTS for PDCH: TRX=%d "
"TS=%d FN=%d block_nr=%d scheduling USF=%d for "
"required uplink resource of UL TFI=%d\n", trx, ts, fn,
block_nr, tbf->m_usf[ts], tfi);
/* next TBF to handle resource is the next one */
pdch->next_ul_tfi = (tfi + 1) & 31;
break;
}
return tbf;
}
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 = the_pcu->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(
uint8_t trx, uint8_t ts, uint32_t fn,
uint8_t block_nr, struct gprs_rlcmac_pdch *pdch,
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 };
/* 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(GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ))
msg = tbfs->ul_ass->create_packet_access_reject();
else if (tbf == tbfs->ul_ass && tbf->direction ==
GPRS_RLCMAC_DL_TBF)
if (tbf->ul_ass_state_is(GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ))
msg = tbfs->ul_ass->create_packet_access_reject();
else
msg = tbfs->ul_ass->create_ul_ass(fn, ts);
else if (tbf == tbfs->dl_ass && tbf->direction == GPRS_RLCMAC_UL_TBF)
msg = tbfs->dl_ass->create_dl_ass(fn, ts);
else if (tbf == tbfs->ul_ack)
msg = tbfs->ul_ack->create_ul_ack(fn, ts);
/* else: if tbf/ms is pending to send tx_neigbhourData or tx_CellchangeContinue, send it */
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 = tbfs->dl_ass->create_dl_ass(fn, ts);
} else if (tbfs->ul_ass) {
tbf = tbfs->ul_ass;
msg = tbfs->ul_ass->create_ul_ass(fn, ts);
}
}
/* any message */
if (msg) {
if (!tbf) {
LOGP(DRLCMACSCHED, LOGL_ERROR,
"Control message to be scheduled, but no TBF (TRX=%d, TS=%d)\n", trx, ts);
msgb_free(msg);
return NULL;
}
tbf->rotate_in_list();
LOGP(DRLCMACSCHED, LOGL_DEBUG, "Scheduling control "
"message at RTS for %s (TRX=%d, TS=%d)\n",
tbf_name(tbf), trx, ts);
rate_ctr_inc(&tbf->ms()->ctrs->ctr[MS_CTR_DL_CTRL_MSG_SCHED]);
return msg;
}
/* schedule PACKET PAGING REQUEST, if any are pending */
msg = pdch->packet_paging_request();
if (msg) {
LOGP(DRLCMACSCHED, LOGL_DEBUG, "Scheduling paging request "
"message at RTS for (TRX=%d, TS=%d)\n", trx, ts);
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,
uint8_t ts, uint32_t fn, int age)
{
const gprs_rlc_dl_window *w = static_cast<gprs_rlc_dl_window *>(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));
if (tbf->is_control_ts(ts) && tbf->need_control_ts())
return DL_PRIO_CONTROL;
if (tbf->is_control_ts(ts) && age > age_thresh2 && age_thresh2 > 0)
return DL_PRIO_HIGH_AGE;
if ((tbf->state_is(GPRS_RLCMAC_FLOW) && tbf->have_data()) || w->resend_needed() >= 0)
return DL_PRIO_NEW_DATA;
if (tbf->is_control_ts(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;
}
static struct msgb *sched_select_downlink(struct gprs_rlcmac_bts *bts,
uint8_t trx, uint8_t ts, uint32_t fn,
uint8_t block_nr, struct gprs_rlcmac_pdch *pdch, 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(GPRS_RLCMAC_FLOW)
&& tbf->state_is_not(GPRS_RLCMAC_FINISHED))
continue;
/* waiting for CCCH IMM.ASS confirm */
if (tbf->m_wait_confirm)
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, ts, 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 && tbf->is_egprs_enabled() &&
(prio !=DL_PRIO_CONTROL && prio != DL_PRIO_NEW_DATA)) {
LOGP(DRLCMACSCHED, LOGL_DEBUG, "Cannot downgrade EGPRS TBF with prio %d\n", prio);
continue;
}
/* get the TBF with the highest priority */
if (prio > max_prio) {
prio_tfi = tfi;
prio_tbf = tbf;
max_prio = prio;
}
}
if (prio_tbf) {
LOGP(DRLCMACSCHED, LOGL_DEBUG, "Scheduling data message at "
"RTS for DL TFI=%d (TRX=%d, TS=%d) prio=%d mcs_mode_restrict=%s\n",
prio_tfi, trx, ts, 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, ts, req_mcs_kind);
*is_egprs = ms_mode(prio_tbf->ms()) != GPRS;
}
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_ul_tbf *usf_tbf;
uint8_t usf;
struct msgb *msg = NULL;
uint32_t poll_fn, sba_fn;
enum pcu_gsmtap_category gsmtap_cat;
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()) {
LOGP(DRLCMACSCHED, LOGL_ERROR, "Received RTS on disabled PDCH: "
"TRX=%d TS=%d\n", trx, ts);
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 */
}
poll_fn = sched_poll(bts, trx, ts, fn, block_nr, &tbf_cand);
/* check uplink resource for polling */
if (tbf_cand.poll) {
LOGP(DRLCMACSCHED, LOGL_DEBUG, "Received RTS for PDCH: TRX=%d "
"TS=%d FN=%d block_nr=%d scheduling free USF for "
"polling at FN=%d of %s\n", trx, ts, fn,
block_nr, poll_fn, tbf_name(tbf_cand.poll));
usf = USF_UNUSED;
/* else. check for sba */
} else if ((sba_fn = bts_sba(bts)->sched(trx, ts, fn, block_nr)) != 0xffffffff) {
LOGP(DRLCMACSCHED, LOGL_DEBUG, "Received RTS for PDCH: TRX=%d "
"TS=%d FN=%d block_nr=%d scheduling free USF for "
"single block allocation at FN=%d\n", trx, ts, fn,
block_nr, sba_fn);
usf = USF_UNUSED;
/* else, we search for uplink resource */
} else {
usf_tbf = sched_select_uplink(trx, ts, fn, block_nr, pdch, require_gprs_only);
if (usf_tbf) {
usf = usf_tbf->m_usf[ts];
/* 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 (req_mcs_kind == EGPRS && ms_mode(usf_tbf->ms()) != EGPRS)
req_mcs_kind = EGPRS_GMSK;
} else {
usf = USF_UNUSED;
}
}
/* Prio 1: select control message */
if ((msg = sched_select_ctrl_msg(trx, ts, fn, block_nr, pdch, &tbf_cand))) {
gsmtap_cat = PCU_GSMTAP_C_DL_CTRL;
}
/* Prio 2: select data message for downlink */
else if((msg = sched_select_downlink(bts, trx, ts, fn, block_nr, pdch, 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 contol message */
else if ((msg = sched_dummy())) {
/* increase counter */
gsmtap_cat = PCU_GSMTAP_C_DL_DUMMY;
} else {
return -ENOMEM;
}
if (tx_is_egprs && pdch->has_gprs_only_tbf_attached()) {
pdch->fn_without_cs14 += 1;
} else {
pdch->fn_without_cs14 = 0;
}
/* msg is now available */
bts_do_rate_ctr_add(bts, CTR_RLC_DL_BYTES, msg->data_len);
/* set USF */
OSMO_ASSERT(msgb_length(msg) > 0);
msg->data[0] = (msg->data[0] & 0xf8) | usf;
/* Used to measure the leak rate, count all blocks */
gprs_bssgp_update_frames_sent();
/* Send to GSMTAP */
tap_n_acc(msg, bts, trx, ts, fn, gsmtap_cat);
/* send PDTCH/PACCH to L1 */
pcu_l1if_tx_pdtch(msg, trx, ts, bts->trx[trx].arfcn, fn, block_nr);
return 0;
}
View Git Blame Copy Permalink