Bluetooth: ISO: extend API for setting SDU interval

The BT Core Spec v5.4 allows separate SDU_Interval to
be set on C_To_P and P_To_C directions,
but this is not possible with the existing interface.

This PR splits the interval parameter in the call to
bt_iso_sig_create into one for C_To_P
and one for P_To_C

Signed-off-by: Andries Kruithof <[email protected]>

include/zephyr/bluetooth/iso.h

@@ -335,19 +335,33 @@ struct bt_iso_cig_param {
 	 */
 	uint8_t num_cis;
 
-	/** @brief Channel interval in us.
+	/** @brief Channel interval in us for SDUs sent from Central to Peripheral.
 	 *
 	 *  Value range BT_ISO_SDU_INTERVAL_MIN - BT_ISO_SDU_INTERVAL_MAX.
 	 */
-	uint32_t interval;
+	uint32_t c_to_p_interval;
 
-	/** @brief Channel Latency in ms.
+	/** @brief Channel interval in us for SDUs sent from Peripheral to Central.
+	 *
+	 *  Value range BT_ISO_SDU_INTERVAL_MIN - BT_ISO_SDU_INTERVAL_MAX.
+	 */
+	uint32_t p_to_c_interval;
+
+	/** @brief Channel Latency in ms for SDUs sent from Central to Peripheral
 	 *
 	 *  Value range BT_ISO_LATENCY_MIN - BT_ISO_LATENCY_MAX.
 	 *
 	 *  This value is ignored if any advanced ISO parameters are set.
 	 */
-	uint16_t latency;
+	uint16_t c_to_p_latency;
+
+	/** @brief Channel Latency in ms for SDUs sent from Peripheral to Central
+	 *
+	 *  Value range BT_ISO_LATENCY_MIN - BT_ISO_LATENCY_MAX.
+	 *
+	 *  This value is ignored if any advanced ISO parameters are set.
+	 */
+	uint16_t p_to_c_latency;
 
 	/** @brief Channel peripherals sleep clock accuracy Only for CIS
 	 *

samples/bluetooth/central_iso/src/main.c

@@ -251,8 +251,10 @@ int main(void)
 	param.sca = BT_GAP_SCA_UNKNOWN;
 	param.packing = 0;
 	param.framing = 0;
-	param.latency = 10; /* ms */
-	param.interval = interval_us; /* us */
+	param.c_to_p_latency = 10; /* ms */
+	param.p_to_c_latency = 10; /* ms */
+	param.c_to_p_interval = interval_us; /* us */
+	param.p_to_c_interval = interval_us; /* us */
 
 	err = bt_iso_cig_create(&param, &cig);
 

samples/bluetooth/iso_connected_benchmark/src/main.c

@@ -116,8 +116,10 @@ static struct bt_iso_chan_qos iso_qos = {
 };
 
 static struct bt_iso_cig_param cig_create_param = {
-	.interval = DEFAULT_CIS_INTERVAL_US, /* in microseconds */
-	.latency = DEFAULT_CIS_LATENCY_MS, /* milliseconds */
+	.c_to_p_interval = DEFAULT_CIS_INTERVAL_US, /* in microseconds */
+	.p_to_c_interval = DEFAULT_CIS_INTERVAL_US, /* in microseconds */
+	.c_to_p_latency = DEFAULT_CIS_LATENCY_MS, /* milliseconds */
+	.p_to_c_latency = DEFAULT_CIS_LATENCY_MS, /* milliseconds */
 	.sca = BT_GAP_SCA_UNKNOWN,
 	.packing = DEFAULT_CIS_PACKING,
 	.framing = DEFAULT_CIS_FRAMING,
@@ -179,17 +181,21 @@ static void iso_send(struct bt_iso_chan *chan)
 	int ret;
 	struct net_buf *buf;
 	struct iso_chan_work *chan_work;
+	uint32_t interval;
 
 	chan_work = CONTAINER_OF(chan, struct iso_chan_work, chan);
 
 	if (!chan_work->info.can_send) {
 		return;
 	}
 
+	interval = (role == ROLE_CENTRAL) ?
+		   cig_create_param.c_to_p_interval : cig_create_param.p_to_c_interval;
+
 	buf = net_buf_alloc(&tx_pool, K_FOREVER);
 	if (buf == NULL) {
 		LOG_ERR("Could not allocate buffer");
-		k_work_reschedule(&chan_work->send_work, K_USEC(cig_create_param.interval));
+		k_work_reschedule(&chan_work->send_work, K_USEC(interval));
 		return;
 	}
 
@@ -201,7 +207,7 @@ static void iso_send(struct bt_iso_chan *chan)
 	if (ret < 0) {
 		LOG_ERR("Unable to send data: %d", ret);
 		net_buf_unref(buf);
-		k_work_reschedule(&chan_work->send_work, K_USEC(cig_create_param.interval));
+		k_work_reschedule(&chan_work->send_work, K_USEC(interval));
 		return;
 	}
 
@@ -541,8 +547,11 @@ static int parse_interval_arg(void)
 	size_t char_count;
 	uint64_t interval;
 
-	printk("Set interval (us) (current %u, default %u)\n",
-	       cig_create_param.interval, DEFAULT_CIS_INTERVAL_US);
+	interval = (role == ROLE_CENTRAL) ?
+		   cig_create_param.c_to_p_interval : cig_create_param.p_to_c_interval;
+
+	printk("Set interval (us) (current %llu, default %u)\n",
+	       interval, DEFAULT_CIS_INTERVAL_US);
 
 	char_count = get_chars(buffer, sizeof(buffer) - 1);
 	if (char_count == 0) {
@@ -566,7 +575,7 @@ static int parse_latency_arg(void)
 	uint64_t latency;
 
 	printk("Set latency (ms) (current %u, default %u)\n",
-	       cig_create_param.latency, DEFAULT_CIS_LATENCY_MS);
+	       cig_create_param.c_to_p_latency, DEFAULT_CIS_LATENCY_MS);
 
 	char_count = get_chars(buffer, sizeof(buffer) - 1);
 	if (char_count == 0) {
@@ -854,8 +863,10 @@ static int parse_cig_args(void)
 	}
 #endif /* CONFIG_BT_ISO_ADVANCED */
 
-	cig_create_param.interval = interval;
-	cig_create_param.latency = latency;
+	cig_create_param.c_to_p_interval = interval;
+	cig_create_param.p_to_c_interval = interval;
+	cig_create_param.c_to_p_latency = latency;
+	cig_create_param.p_to_c_latency = latency;
 	cig_create_param.num_cis = cis_count;
 #if defined(CONFIG_BT_ISO_ADVANCED)
 	cig_create_param.c_to_p_ft = c_to_p_ft;
@@ -923,9 +934,11 @@ static int change_central_settings(void)
 	int err;
 
 	printk("Change CIG settings (y/N)? (Current settings: cis_count=%u, "
-	       "interval=%u, latency=%u)\n",
-	       cig_create_param.num_cis, cig_create_param.interval,
-	       cig_create_param.latency);
+	       "C to P interval=%u, P to C interval=%u "
+	       "C to P latency=%u, P to C latency=%u)\n",
+	       cig_create_param.num_cis, cig_create_param.c_to_p_interval,
+	       cig_create_param.p_to_c_interval, cig_create_param.c_to_p_latency,
+	       cig_create_param.p_to_c_latency);
 
 	c = tolower(console_getchar());
 	if (c == 'y') {
@@ -934,9 +947,12 @@ static int change_central_settings(void)
 			return err;
 		}
 
-		printk("New settings: cis_count=%u, inteval=%u, latency=%u\n",
-		       cig_create_param.num_cis, cig_create_param.interval,
-		       cig_create_param.latency);
+		printk("New settings: cis_count=%u, C to P interval=%u, "
+		       "P TO C interval=%u, C to P latency=%u "
+		       "P TO C latency=%u\n",
+		       cig_create_param.num_cis, cig_create_param.c_to_p_interval,
+		       cig_create_param.p_to_c_interval, cig_create_param.c_to_p_latency,
+		       cig_create_param.p_to_c_latency);
 	}
 
 	printk("Change TX settings (y/N)? (Current settings: rtn=%u, "

subsys/bluetooth/audio/bap_unicast_client.c

@@ -2089,8 +2089,10 @@ static void bt_audio_codec_qos_to_cig_param(struct bt_iso_cig_param *cig_param,
 {
 	cig_param->framing = qos->framing;
 	cig_param->packing = BT_ISO_PACKING_SEQUENTIAL; /*  TODO: Add to QoS struct */
-	cig_param->interval = qos->interval;
-	cig_param->latency = qos->latency;
+	cig_param->c_to_p_interval = qos->interval;
+	cig_param->p_to_c_interval = qos->interval;
+	cig_param->c_to_p_latency = qos->latency;
+	cig_param->p_to_c_latency = qos->latency;
 	cig_param->sca = BT_GAP_SCA_UNKNOWN;
 }
 

subsys/bluetooth/host/iso.c

@@ -1524,18 +1524,22 @@ static struct net_buf *hci_le_set_cig_params(const struct bt_iso_cig *cig,
 	memset(req, 0, sizeof(*req));
 
 	req->cig_id = cig->id;
-	req->c_latency = sys_cpu_to_le16(param->latency);
-	req->p_latency = sys_cpu_to_le16(param->latency);
-	sys_put_le24(param->interval, req->c_interval);
-	sys_put_le24(param->interval, req->p_interval);
+	req->c_latency = sys_cpu_to_le16(param->c_to_p_latency);
+	req->p_latency = sys_cpu_to_le16(param->p_to_c_latency);
+	sys_put_le24(param->c_to_p_interval, req->c_interval);
+	sys_put_le24(param->p_to_c_interval, req->p_interval);
 
 	req->sca = param->sca;
 	req->packing = param->packing;
 	req->framing = param->framing;
 	req->num_cis = param->num_cis;
 
-	LOG_DBG("id %u, latency %u, interval %u, sca %u, packing %u, framing %u, num_cis %u",
-		cig->id, param->latency, param->interval, param->sca, param->packing,
+	LOG_DBG("id %u, latency C to P %u, latency P to C %u, "
+		"interval C to P %u, interval P to C %u, "
+		"sca %u, packing %u, framing %u, num_cis %u",
+		cig->id, param->c_to_p_latency, param->p_to_c_latency,
+		param->c_to_p_interval, param->p_to_c_interval,
+		param->sca, param->packing,
 		param->framing, param->num_cis);
 
 	/* Program the cis parameters */
@@ -1611,8 +1615,8 @@ static struct net_buf *hci_le_set_cig_test_params(const struct bt_iso_cig *cig,
 	memset(req, 0, sizeof(*req));
 
 	req->cig_id = cig->id;
-	sys_put_le24(param->interval, req->c_interval);
-	sys_put_le24(param->interval, req->p_interval);
+	sys_put_le24(param->c_to_p_interval, req->c_interval);
+	sys_put_le24(param->p_to_c_interval, req->p_interval);
 
 	req->c_ft = param->c_to_p_ft;
 	req->p_ft = param->p_to_c_ft;
@@ -1859,16 +1863,28 @@ static bool valid_cig_param(const struct bt_iso_cig_param *param, bool advanced,
 		return false;
 	}
 
-	if (param->interval < BT_ISO_SDU_INTERVAL_MIN ||
-	    param->interval > BT_ISO_SDU_INTERVAL_MAX) {
-		LOG_DBG("Invalid interval: %u", param->interval);
+	if (param->c_to_p_interval < BT_ISO_SDU_INTERVAL_MIN ||
+	    param->c_to_p_interval > BT_ISO_SDU_INTERVAL_MAX) {
+		LOG_DBG("Invalid interval: %u", param->c_to_p_interval);
+		return false;
+	}
+
+	if (param->p_to_c_interval < BT_ISO_SDU_INTERVAL_MIN ||
+	    param->p_to_c_interval > BT_ISO_SDU_INTERVAL_MAX) {
+		LOG_DBG("Invalid interval: %u", param->p_to_c_interval);
 		return false;
 	}
 
 	if (!advanced &&
-	    (param->latency < BT_ISO_LATENCY_MIN ||
-	     param->latency > BT_ISO_LATENCY_MAX)) {
-		LOG_DBG("Invalid latency: %u", param->latency);
+	    (param->c_to_p_latency < BT_ISO_LATENCY_MIN ||
+	     param->c_to_p_latency > BT_ISO_LATENCY_MAX)) {
+		LOG_DBG("Invalid C to P latency: %u", param->c_to_p_latency);
+		return false;
+	}
+	if (!advanced &&
+	    (param->p_to_c_latency < BT_ISO_LATENCY_MIN ||
+	     param->p_to_c_latency > BT_ISO_LATENCY_MAX)) {
+		LOG_DBG("Invalid latency: %u", param->p_to_c_latency);
 		return false;
 	}
 

subsys/bluetooth/shell/iso.c

@@ -181,11 +181,17 @@ static int cmd_cig_create(const struct shell *sh, size_t argc, char *argv[])
 			return -ENOEXEC;
 		}
 
-		param.interval = interval;
+		param.c_to_p_interval = interval;
+		param.p_to_c_interval = interval;
 	} else {
-		param.interval = 10000;
+		param.c_to_p_interval = 10000;
+		param.p_to_c_interval = 10000;
 	}
-	cis_sdu_interval_us = param.interval;
+	/* cis_sdu_internal_us is used to increase the sequence number
+	 * setting it to the lowest interval number ensures that it
+	 * is increased at least once per interval
+	 */
+	cis_sdu_interval_us = MIN(param.c_to_p_interval, param.p_to_c_interval);
 
 	if (argc > 3) {
 		unsigned long packing;

tests/bsim/bluetooth/host/iso/cis/src/cis_central.c

@@ -183,8 +183,10 @@ static void create_cig(void)
 	param.sca = BT_GAP_SCA_UNKNOWN;
 	param.packing = BT_ISO_PACKING_SEQUENTIAL;
 	param.framing = BT_ISO_FRAMING_UNFRAMED;
-	param.latency = 10U;          /* ms */
-	param.interval = interval_us; /* us */
+	param.c_to_p_latency = 10U;          /* ms */
+	param.p_to_c_latency = 10U;          /* ms */
+	param.c_to_p_interval = interval_us; /* us */
+	param.p_to_c_interval = interval_us; /* us */
 
 	err = bt_iso_cig_create(&param, &cig);
 	if (err != 0) {
@@ -210,8 +212,10 @@ static void reconfigure_cig(void)
 	param.sca = BT_GAP_SCA_UNKNOWN;
 	param.packing = BT_ISO_PACKING_SEQUENTIAL;
 	param.framing = BT_ISO_FRAMING_UNFRAMED;
-	param.latency = 10U;          /* ms */
-	param.interval = interval_us; /* us */
+	param.c_to_p_latency = 10U;          /* ms */
+	param.p_to_c_latency = 10U;          /* ms */
+	param.c_to_p_interval = interval_us; /* us */
+	param.p_to_c_interval = interval_us; /* us */
 
 	/* Test modifying existing CIS */
 	default_chan->qos->tx->rtn++;
@@ -225,7 +229,8 @@ static void reconfigure_cig(void)
 
 	/* Test modifying CIG parameter without any CIS */
 	param.num_cis = 0U;
-	param.interval = 7500U; /* us */
+	param.c_to_p_interval = 7500U; /* us */
+	param.p_to_c_interval = 7500U; /* us */
 
 	err = bt_iso_cig_reconfigure(cig, &param);
 	if (err != 0) {
@@ -234,10 +239,24 @@ static void reconfigure_cig(void)
 		return;
 	}
 
+	/* Test modifying to different values for both intervals */
+	param.num_cis = 0U;
+	param.c_to_p_interval = 5000U; /* us */
+	param.p_to_c_interval = 2500U; /* us */
+
+	err = bt_iso_cig_reconfigure(cig, &param);
+	if (err != 0) {
+		FAIL("Failed to reconfigure CIG to different intervals (%d)\n", err);
+
+		return;
+	}
+
+
 	/* Add CIS to the CIG and restore interval to 10ms */
 	param.cis_channels = &channels[1];
 	param.num_cis = 1U;
-	param.interval = interval_us; /* us */
+	param.c_to_p_interval = interval_us; /* us */
+	param.p_to_c_interval = interval_us; /* us */
 
 	err = bt_iso_cig_reconfigure(cig, &param);
 	if (err != 0) {

tests/bsim/bluetooth/ll/cis/src/main.c

@@ -413,11 +413,14 @@ static void test_cis_central(void)
 	cig_param.sca = BT_GAP_SCA_UNKNOWN;
 	cig_param.packing = 0U;
 	cig_param.framing = 0U;
-	cig_param.interval = ISO_INTERVAL_US;
+	cig_param.c_to_p_interval = ISO_INTERVAL_US;
+	cig_param.p_to_c_interval = ISO_INTERVAL_US;
 	if (IS_ENABLED(CONFIG_TEST_FT_SKIP_SUBEVENTS)) {
-		cig_param.latency = ISO_LATENCY_FT_MS;
+		cig_param.c_to_p_latency = ISO_LATENCY_FT_MS;
+		cig_param.p_to_c_latency = ISO_LATENCY_FT_MS;
 	} else {
-		cig_param.latency = ISO_LATENCY_MS;
+		cig_param.c_to_p_latency = ISO_LATENCY_MS;
+		cig_param.p_to_c_latency = ISO_LATENCY_MS;
 	}
 
 	printk("Create CIG...");