trxcon/scheduler: add TCH/H channel support

Change-Id: Ibb2a0850692c5ff86b13b820af10b12085589e67

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 rx_tchf_fn(struct trx_instance *trx, struct trx_ts *ts,
 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",

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 <axilirator@gmail.com>
+ * (C) 2018 by Harald Welte <laforge@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 @@ uint32_t sched_tchh_block_dl_first_fn(enum trx_lchan_type chan,
 	/* 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;
+}

src/host/trxcon/sched_trx.c

@@ -463,7 +463,7 @@ static void sched_trx_reset_lchan(struct trx_lchan_state *lchan)
 	/* 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;
 

src/host/trxcon/sched_trx.h

@@ -171,9 +171,9 @@ struct trx_lchan_state {
 	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 */