diff options
Diffstat (limited to 'src/libbsc/acc_ramp.c')
| -rw-r--r-- | src/libbsc/acc_ramp.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/src/libbsc/acc_ramp.c b/src/libbsc/acc_ramp.c new file mode 100644 index 000000000..3f83d1e1d --- /dev/null +++ b/src/libbsc/acc_ramp.c @@ -0,0 +1,177 @@ +/* (C) 2018 Stefan Sperling <ssperling@sysmocom.de> + * + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as published by + * the Free Software Foundation; either version 3 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 Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + */ + +#include <assert.h> +#include <strings.h> +#include <errno.h> + +#include <osmocom/bsc/debug.h> +#include <osmocom/bsc/acc_ramp.h> +#include <osmocom/bsc/gsm_data.h> + +static void deny_all_accs(struct acc_ramp *acc_ramp) +{ + LOGP(DRLL, LOGL_DEBUG, "(bts=%d) ACC RAMP: denying all Access Control Classes 0-9\n", acc_ramp->bts->nr); + acc_ramp->barred_t2 = 0x03; /* ACC8, ACC9 barred */ + acc_ramp->barred_t3 = 0xff; /* ACC0 - ACC7 barred */ +} + +static void allow_all_accs(struct acc_ramp *acc_ramp) +{ + LOGP(DRLL, LOGL_DEBUG, "(bts=%d) ACC RAMP: allowing all Access Control Classes 0-9\n", acc_ramp->bts->nr); + acc_ramp->barred_t2 = 0x00; /* ACC8, ACC9 allowed */ + acc_ramp->barred_t3 = 0x00; /* ACC0 - ACC7 allowed */ +} + +static void allow_one_acc(struct acc_ramp *acc_ramp, unsigned int acc) +{ + LOGP(DRLL, LOGL_DEBUG, "(bts=%d) ACC RAMP: allowing Access Control Class %u\n", acc_ramp->bts->nr, acc); + assert(acc >= 0 && acc <= 9); + if (acc == 8 || acc == 9) + acc_ramp->barred_t2 &= ~(1 << (acc - 8)); + else + acc_ramp->barred_t3 &= ~(1 << acc); +} + +static unsigned int get_next_step_interval(struct acc_ramp *acc_ramp) +{ + struct gsm_bts *bts = acc_ramp->bts; + + if (acc_ramp->step_interval_is_fixed) + return acc_ramp->step_interval_sec; + + if (bts->chan_load_avg == 0) { + acc_ramp->step_interval_sec = ACC_RAMP_STEP_INTERVAL_MIN; + } else { + /* Scale the step interval to current channel load average. */ + uint64_t load = (bts->chan_load_avg << 8); /* convert to fixed-point */ + acc_ramp->step_interval_sec = ((load * ACC_RAMP_STEP_INTERVAL_MAX) / 100) >> 8; + if (acc_ramp->step_interval_sec < ACC_RAMP_STEP_SIZE_MIN) + acc_ramp->step_interval_sec = ACC_RAMP_STEP_INTERVAL_MIN; + else if (acc_ramp->step_interval_sec > ACC_RAMP_STEP_INTERVAL_MAX) + acc_ramp->step_interval_sec = ACC_RAMP_STEP_INTERVAL_MAX; + } + + LOGP(DRLL, LOGL_DEBUG, "(bts=%d) ACC RAMP: step interval set to %u sec based on %u%% load average\n", + bts->nr, acc_ramp->step_interval_sec, bts->chan_load_avg); + return acc_ramp->step_interval_sec; +} + +static void update_bts_rach_control(struct acc_ramp *acc_ramp) +{ + struct gsm_bts *bts = acc_ramp->bts; + struct gsm_bts_trx *trx; + + /* Update RACH control parameters of this BTS. */ + bts->si_common.rach_control.t2 &= ~0x03; + bts->si_common.rach_control.t2 |= acc_ramp_get_barred_t2(acc_ramp); + bts->si_common.rach_control.t3 = acc_ramp_get_barred_t3(acc_ramp); + + /* Send updated system information to all TRX. */ + llist_for_each_entry_reverse(trx, &bts->trx_list, list) + gsm_bts_trx_set_system_infos(trx); +} + +static void do_ramping_step(void *data) +{ + struct acc_ramp *acc_ramp = data; + int i; + + /* Shortcut in case we only do one ramping step. */ + if (acc_ramp->step_size == ACC_RAMP_STEP_SIZE_MAX) { + allow_all_accs(acc_ramp); + return; + } + + /* Allow 'step_size' ACCs, starting from ACC0. ACC9 will be allowed last. */ + for (i = 0; i < acc_ramp->step_size; i++) { + int idx = ffs(acc_ramp->barred_t3); + if (idx > 0) { + /* one of ACC0-ACC7 is still bared */ + allow_one_acc(acc_ramp, idx - 1); + } else { + idx = ffs(acc_ramp->barred_t2); + if (idx == 1 || idx == 2) { + /* ACC8 or ACC9 is still barred */ + allow_one_acc(acc_ramp, idx - 1 + 8); + } else { + /* all ACCs are now allowed */ + break; + } + } + } + + + update_bts_rach_control(acc_ramp); + + /* If we have not allowed all ACCs yet, schedule another ramping step. */ + if (acc_ramp_get_barred_t2(acc_ramp) != 0x00 || + acc_ramp_get_barred_t3(acc_ramp) != 0x00) + osmo_timer_schedule(&acc_ramp->step_timer, get_next_step_interval(acc_ramp), 0); +} + +void acc_ramp_init(struct acc_ramp *acc_ramp, struct gsm_bts *bts) +{ + acc_ramp->bts = bts; + allow_all_accs(acc_ramp); + acc_ramp->step_size = ACC_RAMP_STEP_SIZE_DEFAULT; + acc_ramp->step_interval_sec = ACC_RAMP_STEP_INTERVAL_DEFAULT; + acc_ramp->step_interval_is_fixed = false; + osmo_timer_setup(&acc_ramp->step_timer, do_ramping_step, acc_ramp); +} + +int acc_ramp_set_step_size(struct acc_ramp *acc_ramp, enum acc_ramp_step_size step_size) +{ + if (step_size < ACC_RAMP_STEP_SIZE_MIN || step_size > ACC_RAMP_STEP_SIZE_MAX) + return -ERANGE; + + acc_ramp->step_size = step_size; + return 0; +} + +int acc_ramp_set_step_interval(struct acc_ramp *acc_ramp, unsigned int step_interval) +{ + if (step_interval < ACC_RAMP_STEP_INTERVAL_MIN || step_interval > ACC_RAMP_STEP_INTERVAL_MAX) + return -ERANGE; + + acc_ramp->step_interval_sec = step_interval; + acc_ramp->step_interval_is_fixed = true; + return 0; +} + +void acc_ramp_set_step_interval_dynamic(struct acc_ramp *acc_ramp) +{ + acc_ramp->step_interval_is_fixed = false; +} + +void acc_ramp_start(struct acc_ramp *acc_ramp) +{ + /* Abort any previously running ramping process. */ + acc_ramp_abort(acc_ramp); + + /* Set all ACCs to denied and start ramping up. */ + deny_all_accs(acc_ramp); + do_ramping_step(acc_ramp); +} + +void acc_ramp_abort(struct acc_ramp *acc_ramp) +{ + if (osmo_timer_pending(&acc_ramp->step_timer)) + osmo_timer_del(&acc_ramp->step_timer); +} |