--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/L1/cfile/tch_feature.c	Thu Jun 09 00:02:41 2016 +0000
@@ -0,0 +1,152 @@
+/*
+ * This module is a FreeCalypso addition; it contains code implementing
+ * our custom voice TCH rerouting feature.
+ */
+
+#include "config.h"
+#include "l1_confg.h"
+#include "l1_types.h"
+#include "sys_types.h"
+#include <string.h>
+#include "l1_const.h"
+#include "l1_defty.h"
+#include "l1_varex.h"
+#include "l1_trace.h"
+#include "tch_feature.h"
+
+T_RVT_USER_ID tch_reroute_rvt_id;
+BOOL tch_reroute_downlink;
+
+void tch_send_downlink_bits(API *dsp_buffer)
+{
+	T_RVT_BUFFER buf;
+	T_RVT_RET rc;
+	UINT8 *dp;
+	UWORD16 apiword;
+	int i;
+
+	rc = rvt_mem_alloc(tch_reroute_rvt_id, 41, &buf);
+	if (rc != RVT_OK)
+		return;
+	dp = buf;
+	*dp++ = TCH_DLBITS_IND;
+	for (i = 0; i < 20; i++) {
+		apiword = dsp_buffer[i];
+		*dp++ = apiword >> 8;
+		*dp++ = apiword;
+	}
+	rvt_send_trace_no_cpy(buf, tch_reroute_rvt_id, 41, RVT_BINARY_FORMAT);
+}
+
+static void send_tch_ulbits_conf()
+{
+	T_RVT_BUFFER buf;
+	T_RVT_RET rc;
+
+	rc = rvt_mem_alloc(tch_reroute_rvt_id, 1, &buf);
+	if (rc == RVT_OK) {
+		buf[0] = TCH_ULBITS_CONF;
+		rvt_send_trace_no_cpy(buf, tch_reroute_rvt_id, 1,
+					RVT_BINARY_FORMAT);
+	}
+}
+
+#define	UPLINK_QUEUE_SIZE	5
+#define	WORDS_PER_ENTRY		17
+
+static UWORD16 uplink_data[UPLINK_QUEUE_SIZE][WORDS_PER_ENTRY];
+static volatile int ul_read_ptr, ul_write_ptr;
+
+void tch_substitute_uplink(API *dsp_buffer)
+{
+	int read_ptr;
+	int i;
+
+	read_ptr = ul_read_ptr;
+	if (read_ptr == ul_write_ptr) {
+		/* no uplink substitution */
+		l1s_dsp_com.dsp_ndb_ptr->d_tch_mode &= ~B_PLAY_UL;
+		return;
+	}
+	for (i = 0; i < WORDS_PER_ENTRY; i++)
+		dsp_buffer[i+3] = uplink_data[read_ptr][i];
+	// Fill data block Header...
+	dsp_buffer[0] = (1 << B_BLUD);		// 1st word: Set B_BLU bit.
+	dsp_buffer[1] = 0;			// 2nd word: cleared.
+	dsp_buffer[2] = 0;			// 3rd word: cleared.
+	l1s_dsp_com.dsp_ndb_ptr->d_tch_mode |= B_PLAY_UL;
+	/* advance the read pointer and send TCH_ULBITS_CONF */
+	read_ptr++;
+	if (read_ptr >= UPLINK_QUEUE_SIZE)
+		read_ptr = 0;
+	ul_read_ptr = read_ptr;
+	send_tch_ulbits_conf();
+}
+
+static void handle_tch_ulbits_req(T_RVT_BUFFER pkt)
+{
+	int write_ptr, write_next, i;
+	UINT8 *sp;
+
+	write_ptr = ul_write_ptr;
+	write_next = write_ptr + 1;
+	if (write_next >= UPLINK_QUEUE_SIZE)
+		write_next = 0;
+	if (write_next == ul_read_ptr)	/* queue full */
+		return;
+	sp = pkt + 1;
+	for (i = 0; i < WORDS_PER_ENTRY; i++) {
+		uplink_data[write_ptr][i] = (sp[0] << 8) | sp[1];
+		sp += 2;
+	}
+	ul_write_ptr = write_next;
+}
+
+static void handle_tch_config_req(T_RVT_BUFFER pkt)
+{
+	UWORD8 config;
+	T_RVT_BUFFER buf;
+	T_RVT_RET rc;
+
+	config = pkt[1] & 0x01;
+	tch_reroute_downlink = config;
+
+	/* send TCH_CONFIG_CONF response */
+	rc = rvt_mem_alloc(tch_reroute_rvt_id, 2, &buf);
+	if (rc == RVT_OK) {
+		buf[0] = TCH_CONFIG_CONF;
+		buf[1] = config;
+		rvt_send_trace_no_cpy(buf, tch_reroute_rvt_id, 2,
+					RVT_BINARY_FORMAT);
+	}
+}
+
+/*
+ * The following function is the callback registered with RVT; it gets
+ * called in RVT HISR context.
+ */
+static void tch_rvt_input_callback(T_RVT_BUFFER pkt, UINT16 pktlen)
+{
+	if (pktlen < 1)
+		return;
+	switch (pkt[0]) {
+	case TCH_CONFIG_REQ:
+		if (pktlen != 2)
+			return;
+		handle_tch_config_req(pkt);
+		break;
+	case TCH_ULBITS_REQ:
+		if (pktlen < 34)
+			return;
+		handle_tch_ulbits_req(pkt);
+		break;
+	}
+}
+
+void feature_tch_reroute_init()
+{
+	rvt_register_id("TCH", &tch_reroute_rvt_id, tch_rvt_input_callback);
+	tch_reroute_downlink = FALSE;
+	ul_read_ptr = 0;
+	ul_write_ptr = 0;
+}