| /* |
| * OsmocomBB <-> SDR connection bridge |
| * TDMA scheduler: handlers for DL / UL bursts on logical channels |
| * |
| * (C) 2018-2020 by Vadim Yanitskiy <axilirator@gmail.com> |
| * (C) 2018 by Harald Welte <laforge@gnumonks.org> |
| * |
| * All Rights Reserved |
| * |
| * 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., |
| * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| */ |
| |
| #include <errno.h> |
| #include <string.h> |
| #include <stdint.h> |
| #include <stdbool.h> |
| |
| #include <osmocom/core/logging.h> |
| #include <osmocom/core/utils.h> |
| #include <osmocom/core/bits.h> |
| |
| #include <osmocom/gsm/protocol/gsm_04_08.h> |
| #include <osmocom/gsm/gsm_utils.h> |
| |
| #include <osmocom/coding/gsm0503_coding.h> |
| #include <osmocom/codec/codec.h> |
| |
| #include "l1ctl_proto.h" |
| #include "scheduler.h" |
| #include "sched_trx.h" |
| #include "logging.h" |
| #include "trx_if.h" |
| #include "l1ctl.h" |
| |
| static const uint8_t tch_h0_traffic_block_map[3][4] = { |
| /* B0(0,2,4,6), B1(4,6,8,10), B2(8,10,0,2) */ |
| { 0, 2, 4, 6 }, |
| { 4, 6, 8, 10 }, |
| { 8, 10, 0, 2 }, |
| }; |
| |
| static const uint8_t tch_h1_traffic_block_map[3][4] = { |
| /* B0(1,3,5,7), B1(5,7,9,11), B2(9,11,1,3) */ |
| { 1, 3, 5, 7 }, |
| { 5, 7, 9, 11 }, |
| { 9, 11, 1, 3 }, |
| }; |
| |
| static const uint8_t tch_h0_dl_facch_block_map[3][6] = { |
| /* B0(4,6,8,10,13,15), B1(13,15,17,19,21,23), B2(21,23,0,2,4,6) */ |
| { 4, 6, 8, 10, 13, 15 }, |
| { 13, 15, 17, 19, 21, 23 }, |
| { 21, 23, 0, 2, 4, 6 }, |
| }; |
| |
| static const uint8_t tch_h0_ul_facch_block_map[3][6] = { |
| /* B0(0,2,4,6,8,10), B1(8,10,13,15,17,19), B2(17,19,21,23,0,2) */ |
| { 0, 2, 4, 6, 8, 10 }, |
| { 8, 10, 13, 15, 17, 19 }, |
| { 17, 19, 21, 23, 0, 2 }, |
| }; |
| |
| static const uint8_t tch_h1_dl_facch_block_map[3][6] = { |
| /* B0(5,7,9,11,14,16), B1(14,16,18,20,22,24), B2(22,24,1,3,5,7) */ |
| { 5, 7, 9, 11, 14, 16 }, |
| { 14, 16, 18, 20, 22, 24 }, |
| { 22, 24, 1, 3, 5, 7 }, |
| }; |
| |
| const uint8_t tch_h1_ul_facch_block_map[3][6] = { |
| /* B0(1,3,5,7,9,11), B1(9,11,14,16,18,20), B2(18,20,22,24,1,3) */ |
| { 1, 3, 5, 7, 9, 11 }, |
| { 9, 11, 14, 16, 18, 20 }, |
| { 18, 20, 22, 24, 1, 3 }, |
| }; |
| |
| /** |
| * Can a TCH/H block transmission be initiated / finished |
| * on a given frame number and a given channel type? |
| * |
| * See GSM 05.02, clause 7, table 1 |
| * |
| * @param chan channel type (TRXC_TCHH_0 or TRXC_TCHH_1) |
| * @param fn the current frame number |
| * @param ul Uplink or Downlink? |
| * @param facch FACCH/H or traffic? |
| * @param start init or end of transmission? |
| * @return true (yes) or false (no) |
| */ |
| bool sched_tchh_block_map_fn(enum trx_lchan_type chan, |
| uint32_t fn, bool ul, bool facch, bool start) |
| { |
| uint8_t fn_mf; |
| int i = 0; |
| |
| /* Just to be sure */ |
| OSMO_ASSERT(chan == TRXC_TCHH_0 || chan == TRXC_TCHH_1); |
| |
| /* Calculate a modulo */ |
| fn_mf = facch ? (fn % 26) : (fn % 13); |
| |
| #define MAP_GET_POS(map) \ |
| (start ? 0 : ARRAY_SIZE(map[i]) - 1) |
| |
| #define BLOCK_MAP_FN(map) \ |
| do { \ |
| if (map[i][MAP_GET_POS(map)] == fn_mf) \ |
| return true; \ |
| } while (++i < ARRAY_SIZE(map)) |
| |
| /* Choose a proper block map */ |
| if (facch) { |
| if (ul) { |
| if (chan == TRXC_TCHH_0) |
| BLOCK_MAP_FN(tch_h0_ul_facch_block_map); |
| else |
| BLOCK_MAP_FN(tch_h1_ul_facch_block_map); |
| } else { |
| if (chan == TRXC_TCHH_0) |
| BLOCK_MAP_FN(tch_h0_dl_facch_block_map); |
| else |
| BLOCK_MAP_FN(tch_h1_dl_facch_block_map); |
| } |
| } else { |
| if (chan == TRXC_TCHH_0) |
| BLOCK_MAP_FN(tch_h0_traffic_block_map); |
| else |
| BLOCK_MAP_FN(tch_h1_traffic_block_map); |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Calculates a frame number of the first burst |
| * using given frame number of the last burst. |
| * |
| * See GSM 05.02, clause 7, table 1 |
| * |
| * @param chan channel type (TRXC_TCHH_0 or TRXC_TCHH_1) |
| * @param last_fn frame number of the last burst |
| * @param facch FACCH/H or traffic? |
| * @return either frame number of the first burst, |
| * or fn=last_fn if calculation failed |
| */ |
| uint32_t sched_tchh_block_dl_first_fn(enum trx_lchan_type chan, |
| uint32_t last_fn, bool facch) |
| { |
| uint8_t fn_mf, fn_diff; |
| int i = 0; |
| |
| /* Just to be sure */ |
| OSMO_ASSERT(chan == TRXC_TCHH_0 || chan == TRXC_TCHH_1); |
| |
| /* Calculate a modulo */ |
| fn_mf = facch ? (last_fn % 26) : (last_fn % 13); |
| |
| #define BLOCK_FIRST_FN(map) \ |
| do { \ |
| if (map[i][ARRAY_SIZE(map[i]) - 1] == fn_mf) { \ |
| fn_diff = GSM_TDMA_FN_DIFF(fn_mf, map[i][0]); \ |
| return GSM_TDMA_FN_SUB(last_fn, fn_diff); \ |
| } \ |
| } while (++i < ARRAY_SIZE(map)) |
| |
| /* Choose a proper block map */ |
| if (facch) { |
| if (chan == TRXC_TCHH_0) |
| BLOCK_FIRST_FN(tch_h0_dl_facch_block_map); |
| else |
| BLOCK_FIRST_FN(tch_h1_dl_facch_block_map); |
| } else { |
| if (chan == TRXC_TCHH_0) |
| BLOCK_FIRST_FN(tch_h0_traffic_block_map); |
| else |
| BLOCK_FIRST_FN(tch_h1_traffic_block_map); |
| } |
| |
| LOGP(DSCHD, LOGL_ERROR, "Failed to calculate TDMA " |
| "frame number of the first burst of %s block, " |
| "using the current fn=%u\n", facch ? |
| "FACCH/H" : "TCH/H", last_fn); |
| |
| /* Couldn't calculate the first fn, return the last */ |
| return last_fn; |
| } |
| |
| int rx_tchh_fn(struct trx_instance *trx, struct trx_ts *ts, |
| struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid, |
| const sbit_t *bits, const struct trx_meas_set *meas) |
| { |
| const struct trx_lchan_desc *lchan_desc; |
| int n_errors = -1, n_bits_total, rc; |
| sbit_t *buffer, *offset; |
| uint8_t l2[128], *mask; |
| size_t l2_len; |
| |
| /* Set up pointers */ |
| lchan_desc = &trx_lchan_desc[lchan->type]; |
| mask = &lchan->rx_burst_mask; |
| buffer = lchan->rx_bursts; |
| |
| LOGP(DSCHD, LOGL_DEBUG, "Traffic received on %s: fn=%u ts=%u bid=%u\n", |
| lchan_desc->name, fn, ts->index, bid); |
| |
| if (*mask == 0x00) { |
| /* Align to the first burst */ |
| if (bid > 0) |
| return 0; |
| |
| /* Align reception of the first FACCH/H frame */ |
| if (lchan->tch_mode == GSM48_CMODE_SIGN) { |
| if (!sched_tchh_facch_start(lchan->type, fn, 0)) |
| return 0; |
| } else { /* or TCH/H traffic frame */ |
| if (!sched_tchh_traffic_start(lchan->type, fn, 0)) |
| return 0; |
| } |
| } |
| |
| /* Update mask */ |
| *mask |= (1 << bid); |
| |
| /* Store the measurements */ |
| sched_trx_meas_push(lchan, meas); |
| |
| /* Copy burst to the end of buffer of 6 bursts */ |
| offset = buffer + bid * 116 + 464; |
| memcpy(offset, bits + 3, 58); |
| memcpy(offset + 58, bits + 87, 58); |
| |
| /* Wait until the second burst */ |
| if (bid != 1) |
| return 0; |
| |
| /* Wait for complete set of bursts */ |
| if (lchan->tch_mode == GSM48_CMODE_SIGN) { |
| /* FACCH/H is interleaved over 6 bursts */ |
| if ((*mask & 0x3f) != 0x3f) |
| goto bfi_shift; |
| } else { |
| /* Traffic is interleaved over 4 bursts */ |
| if ((*mask & 0x0f) != 0x0f) |
| goto bfi_shift; |
| } |
| |
| /* Skip decoding attempt in case of FACCH/H */ |
| if (lchan->dl_ongoing_facch) { |
| lchan->dl_ongoing_facch = false; |
| goto bfi_shift; /* 2/2 BFI */ |
| } |
| |
| switch (lchan->tch_mode) { |
| case GSM48_CMODE_SIGN: |
| case GSM48_CMODE_SPEECH_V1: /* HR */ |
| rc = gsm0503_tch_hr_decode(l2, buffer, |
| !sched_tchh_facch_end(lchan->type, fn, 0), |
| &n_errors, &n_bits_total); |
| break; |
| case GSM48_CMODE_SPEECH_AMR: /* AMR */ |
| /** |
| * TODO: AMR requires a dedicated loop, |
| * which will be implemented later... |
| */ |
| LOGP(DSCHD, LOGL_ERROR, "AMR isn't supported yet\n"); |
| return -ENOTSUP; |
| default: |
| LOGP(DSCHD, LOGL_ERROR, "Invalid TCH mode: %u\n", lchan->tch_mode); |
| return -EINVAL; |
| } |
| |
| /* Shift buffer by 4 bursts for interleaving */ |
| memcpy(buffer, buffer + 232, 232); |
| memcpy(buffer + 232, buffer + 464, 232); |
| |
| /* Shift burst mask */ |
| *mask = *mask << 2; |
| |
| /* Check decoding result */ |
| if (rc < 4) { |
| /* Calculate AVG of the measurements (assuming 4 bursts) */ |
| sched_trx_meas_avg(lchan, 4); |
| |
| LOGP(DSCHD, LOGL_ERROR, "Received bad TCH frame (%s) " |
| "at fn=%u on %s (rc=%d)\n", burst_mask2str(mask, 6), |
| lchan->meas_avg.fn, lchan_desc->name, rc); |
| |
| /* Send BFI */ |
| goto bfi; |
| } else if (rc == GSM_MACBLOCK_LEN) { |
| /* Skip decoding of the next 2 stolen bursts */ |
| lchan->dl_ongoing_facch = true; |
| |
| /* Calculate AVG of the measurements (FACCH/H takes 6 bursts) */ |
| sched_trx_meas_avg(lchan, 6); |
| |
| /* FACCH/H received, forward to the higher layers */ |
| sched_send_dt_ind(trx, ts, lchan, l2, GSM_MACBLOCK_LEN, |
| n_errors, false, false); |
| |
| /* Send BFI substituting 1/2 stolen TCH frames */ |
| n_errors = -1; /* ensure fake measurements */ |
| goto bfi; |
| } else { |
| /* A good TCH frame received */ |
| l2_len = rc; |
| |
| /* Calculate AVG of the measurements (traffic takes 4 bursts) */ |
| sched_trx_meas_avg(lchan, 4); |
| } |
| |
| /* Send a traffic frame to the higher layers */ |
| return sched_send_dt_ind(trx, ts, lchan, l2, l2_len, |
| n_errors, false, true); |
| |
| bfi_shift: |
| /* Shift buffer */ |
| memcpy(buffer, buffer + 232, 232); |
| memcpy(buffer + 232, buffer + 464, 232); |
| |
| /* Shift burst mask */ |
| *mask = *mask << 2; |
| |
| bfi: |
| /* Didn't try to decode, fake measurements */ |
| if (n_errors < 0) { |
| lchan->meas_avg = (struct trx_meas_set) { |
| .fn = sched_tchh_block_dl_first_fn(lchan->type, fn, false), |
| .toa256 = 0, |
| .rssi = -110, |
| }; |
| |
| /* No bursts => no errors */ |
| n_errors = 0; |
| } |
| |
| /* BFI is not applicable in signalling mode */ |
| if (lchan->tch_mode == GSM48_CMODE_SIGN) |
| return sched_send_dt_ind(trx, ts, lchan, NULL, 0, |
| n_errors, true, false); |
| |
| /* Bad frame indication */ |
| l2_len = sched_bad_frame_ind(l2, lchan); |
| |
| /* Send a BFI frame to the higher layers */ |
| return sched_send_dt_ind(trx, ts, lchan, l2, l2_len, |
| n_errors, true, true); |
| } |
| |
| int tx_tchh_fn(struct trx_instance *trx, struct trx_ts *ts, |
| struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid) |
| { |
| const struct trx_lchan_desc *lchan_desc; |
| ubit_t burst[GSM_BURST_LEN]; |
| ubit_t *buffer, *offset; |
| const uint8_t *tsc; |
| uint8_t *mask; |
| size_t l2_len; |
| int rc; |
| |
| /* Set up pointers */ |
| lchan_desc = &trx_lchan_desc[lchan->type]; |
| mask = &lchan->tx_burst_mask; |
| buffer = lchan->tx_bursts; |
| |
| if (bid > 0) { |
| /* Align to the first burst */ |
| if (*mask == 0x00) |
| return 0; |
| goto send_burst; |
| } |
| |
| if (*mask == 0x00) { |
| /* Align transmission of the first FACCH/H frame */ |
| if (lchan->tch_mode == GSM48_CMODE_SIGN) |
| if (!sched_tchh_facch_start(lchan->type, fn, 1)) |
| return 0; |
| } |
| |
| /* Shift buffer by 2 bursts back for interleaving */ |
| memcpy(buffer, buffer + 232, 232); |
| |
| /* Also shift TX burst mask */ |
| *mask = *mask << 2; |
| |
| /* If FACCH/H blocks are still pending */ |
| if (lchan->ul_facch_blocks > 2) { |
| memcpy(buffer + 232, buffer + 464, 232); |
| goto send_burst; |
| } |
| |
| /* Check the current TCH mode */ |
| switch (lchan->tch_mode) { |
| case GSM48_CMODE_SIGN: |
| case GSM48_CMODE_SPEECH_V1: /* HR */ |
| l2_len = GSM_HR_BYTES + 1; |
| break; |
| case GSM48_CMODE_SPEECH_AMR: /* AMR */ |
| /** |
| * TODO: AMR requires a dedicated loop, |
| * which will be implemented later... |
| */ |
| LOGP(DSCHD, LOGL_ERROR, "AMR isn't supported yet, " |
| "dropping frame...\n"); |
| |
| /* Forget this primitive */ |
| sched_prim_drop(lchan); |
| return -ENOTSUP; |
| default: |
| LOGP(DSCHD, LOGL_ERROR, "Invalid TCH mode: %u, " |
| "dropping frame...\n", lchan->tch_mode); |
| |
| /* Forget this primitive */ |
| sched_prim_drop(lchan); |
| return -EINVAL; |
| } |
| |
| /* Determine payload length */ |
| if (PRIM_IS_FACCH(lchan->prim)) { |
| l2_len = GSM_MACBLOCK_LEN; /* FACCH */ |
| } else if (lchan->prim->payload_len != l2_len) { |
| LOGP(DSCHD, LOGL_ERROR, "Primitive has odd length %zu " |
| "(expected %zu for TCH or %u for FACCH), so dropping...\n", |
| lchan->prim->payload_len, l2_len, GSM_MACBLOCK_LEN); |
| |
| /* Forget this primitive */ |
| sched_prim_drop(lchan); |
| return -EINVAL; |
| } |
| |
| /* Encode the payload */ |
| rc = gsm0503_tch_hr_encode(buffer, lchan->prim->payload, l2_len); |
| if (rc) { |
| LOGP(DSCHD, LOGL_ERROR, "Failed to encode L2 payload (len=%zu): %s\n", |
| lchan->prim->payload_len, osmo_hexdump(lchan->prim->payload, |
| lchan->prim->payload_len)); |
| |
| /* Forget this primitive */ |
| sched_prim_drop(lchan); |
| return -EINVAL; |
| } |
| |
| /* A FACCH/H frame occupies 6 bursts */ |
| if (PRIM_IS_FACCH(lchan->prim)) |
| lchan->ul_facch_blocks = 6; |
| |
| send_burst: |
| /* Determine which burst should be sent */ |
| offset = buffer + bid * 116; |
| |
| /* Update mask */ |
| *mask |= (1 << bid); |
| |
| /* Choose proper TSC */ |
| tsc = sched_nb_training_bits[trx->tsc]; |
| |
| /* Compose a new burst */ |
| memset(burst, 0, 3); /* TB */ |
| memcpy(burst + 3, offset, 58); /* Payload 1/2 */ |
| memcpy(burst + 61, tsc, 26); /* TSC */ |
| memcpy(burst + 87, offset + 58, 58); /* Payload 2/2 */ |
| memset(burst + 145, 0, 3); /* TB */ |
| |
| LOGP(DSCHD, LOGL_DEBUG, "Transmitting %s fn=%u ts=%u burst=%u\n", |
| lchan_desc->name, fn, ts->index, bid); |
| |
| /* Forward burst to transceiver */ |
| sched_trx_handle_tx_burst(trx, ts, lchan, fn, burst); |
| |
| /* In case of a FACCH/H frame, one block less */ |
| if (lchan->ul_facch_blocks) |
| lchan->ul_facch_blocks--; |
| |
| if ((*mask & 0x0f) == 0x0f) { |
| /** |
| * If no more FACCH/H blocks pending, |
| * confirm data / traffic sending |
| */ |
| if (!lchan->ul_facch_blocks) |
| sched_send_dt_conf(trx, ts, lchan, fn, |
| PRIM_IS_TCH(lchan->prim)); |
| |
| /* Forget processed primitive */ |
| sched_prim_drop(lchan); |
| } |
| |
| return 0; |
| } |