Harald Welte has submitted this change and it was merged. ( 
https://gerrit.osmocom.org/10460 )

Change subject: trxcon/scheduler: add TCH/H channel support
......................................................................

trxcon/scheduler: add TCH/H channel support

Change-Id: Ibb2a0850692c5ff86b13b820af10b12085589e67
---
M src/host/trxcon/sched_lchan_desc.c
M src/host/trxcon/sched_lchan_tchh.c
M src/host/trxcon/sched_trx.c
M src/host/trxcon/sched_trx.h
4 files changed, 331 insertions(+), 7 deletions(-)

Approvals:
  Jenkins Builder: Verified
  Harald Welte: Looks good to me, approved



diff --git a/src/host/trxcon/sched_lchan_desc.c 
b/src/host/trxcon/sched_lchan_desc.c
index 37d1273..4cac439 100644
--- a/src/host/trxcon/sched_lchan_desc.c
+++ b/src/host/trxcon/sched_lchan_desc.c
@@ -27,10 +27,7 @@

 /* TODO: implement */
 #define tx_pdtch_fn    NULL
-#define tx_tchh_fn     NULL
-
 #define rx_pdtch_fn    NULL
-#define rx_tchh_fn     NULL

 /* Forward declaration of handlers */
 int rx_data_fn(struct trx_instance *trx, struct trx_ts *ts,
@@ -54,6 +51,14 @@
 int tx_tchf_fn(struct trx_instance *trx, struct trx_ts *ts,
        struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid);

+int rx_tchh_fn(struct trx_instance *trx, struct trx_ts *ts,
+       struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid,
+       sbit_t *bits, int8_t rssi, int16_t toa256);
+
+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 trx_lchan_desc[_TRX_CHAN_MAX] = {
        {
                TRXC_IDLE,              "IDLE",
diff --git a/src/host/trxcon/sched_lchan_tchh.c 
b/src/host/trxcon/sched_lchan_tchh.c
index 316f995..7fb2809 100644
--- a/src/host/trxcon/sched_lchan_tchh.c
+++ b/src/host/trxcon/sched_lchan_tchh.c
@@ -3,6 +3,7 @@
  * TDMA scheduler: handlers for DL / UL bursts on logical channels
  *
  * (C) 2018 by Vadim Yanitskiy <axilira...@gmail.com>
+ * (C) 2018 by Harald Welte <lafo...@gnumonks.org>
  *
  * All Rights Reserved
  *
@@ -23,11 +24,27 @@
  */

 #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 "trxcon.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) */
@@ -181,3 +198,305 @@
        /* 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,
+       sbit_t *bits, int8_t rssi, int16_t toa256)
+{
+       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);
+
+       /**
+        * FIXME: properly update measurements
+        *
+        * Since TCH/H channel is using block-diagonal interleaving,
+        * a single burst may carry 57 bits of one encoded frame,
+        * and 57 bits of another. This should be taken into account.
+        */
+       lchan->meas.rssi_sum += rssi;
+       lchan->meas.toa256_sum += toa256;
+       lchan->meas.rssi_num++;
+       lchan->meas.toa256_num++;
+
+       /* 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) {
+               LOGP(DSCHD, LOGL_ERROR, "Received bad TCH frame ending at "
+                       "fn=%u on %s (rc=%d)\n", 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 TDMA frame number of the first burst */
+               lchan->rx_first_fn = sched_tchh_block_dl_first_fn(lchan->type,
+                       fn, true); /* FACCH/H */
+
+               /* FACCH/H received, forward to the higher layers */
+               sched_send_dt_ind(trx, ts, lchan, l2, GSM_MACBLOCK_LEN,
+                       n_errors, false, false);
+
+               /* 1/2 BFI */
+               goto bfi;
+       } else {
+               /* A good TCH frame received */
+               l2_len = rc;
+       }
+
+       /* Calculate TDMA frame number of the first burst */
+       lchan->rx_first_fn = sched_tchh_block_dl_first_fn(lchan->type,
+               fn, false); /* TCH/H */
+
+       /* 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 */
+       if (n_errors < 0)
+               n_errors = 116 * 2;
+
+       /* Calculate TDMA frame number of the first burst */
+       lchan->rx_first_fn = sched_tchh_block_dl_first_fn(lchan->type,
+               fn, false); /* TCH/H */
+
+       /* 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\n");
+
+               /* 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;
+}
diff --git a/src/host/trxcon/sched_trx.c b/src/host/trxcon/sched_trx.c
index e20da39..023764d 100644
--- a/src/host/trxcon/sched_trx.c
+++ b/src/host/trxcon/sched_trx.c
@@ -463,7 +463,7 @@
        /* TCH specific variables */
        if (CHAN_IS_TCH(lchan->type)) {
                lchan->dl_ongoing_facch = 0;
-               lchan->ul_ongoing_facch = 0;
+               lchan->ul_facch_blocks = 0;
 
                lchan->tch_mode = GSM48_CMODE_SIGN;

diff --git a/src/host/trxcon/sched_trx.h b/src/host/trxcon/sched_trx.h
index 2c8b4d8..08e2489 100644
--- a/src/host/trxcon/sched_trx.h
+++ b/src/host/trxcon/sched_trx.h
@@ -171,9 +171,9 @@
        uint8_t tch_mode;

        /*! \brief FACCH/H on downlink */
-       uint8_t dl_ongoing_facch;
-       /*! \brief FACCH/H on uplink */
-       uint8_t ul_ongoing_facch;
+       bool dl_ongoing_facch;
+       /*! \brief pending FACCH/H blocks on Uplink */
+       uint8_t ul_facch_blocks;

        struct {
                /*! \brief Number of RSSI values */

--
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Gerrit-Project: osmocom-bb
Gerrit-Branch: master
Gerrit-MessageType: merged
Gerrit-Change-Id: Ibb2a0850692c5ff86b13b820af10b12085589e67
Gerrit-Change-Number: 10460
Gerrit-PatchSet: 3
Gerrit-Owner: Vadim Yanitskiy <axilira...@gmail.com>
Gerrit-Reviewer: Harald Welte <lafo...@gnumonks.org>
Gerrit-Reviewer: Jenkins Builder (1000002)
Gerrit-Reviewer: Vadim Yanitskiy <axilira...@gmail.com>

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