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* [PATCH v2 1/2] Bluetooth: HCI: Add initial support for Short Connection Interval feature
@ 2026-05-06 16:06 Luiz Augusto von Dentz
  2026-05-06 16:06 ` [PATCH v2 2/2] Bluetooth: MGMT: Add SCI setting bit(25) Luiz Augusto von Dentz
  2026-05-06 17:53 ` [v2,1/2] Bluetooth: HCI: Add initial support for Short Connection Interval feature bluez.test.bot
  0 siblings, 2 replies; 3+ messages in thread
From: Luiz Augusto von Dentz @ 2026-05-06 16:06 UTC (permalink / raw)
  To: linux-bluetooth

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This adds initial support for SCI related commands, command bits, event
event mask bit and feature bits:

Events:

HCI_LE_Connection_Rate_Change(0x37)

Commands:

HCI_LE_Connection_Rate_Request(0x20a1)
HCI_LE_Set_Default_Rate_Parameters(0x20a2)
HCI_LE_Read_Minimum_Supported_Connection_Interval(0x20a3)

Also update the init sequence to incorporte support for reading SCI
groups and then setting the Default Rate

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 include/net/bluetooth/hci.h      | 52 +++++++++++++++++++
 include/net/bluetooth/hci_core.h | 15 ++++++
 net/bluetooth/hci_core.c         | 14 ++++-
 net/bluetooth/hci_event.c        | 62 ++++++++++++++++++++++
 net/bluetooth/hci_sync.c         | 88 +++++++++++++++++++++++++++++++-
 5 files changed, 229 insertions(+), 2 deletions(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 572b1c620c5d..848ec42de827 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -656,6 +656,7 @@ enum {
 #define HCI_LE_LL_EXT_FEATURE		0x80
 #define HCI_LE_CS			0x40
 #define HCI_LE_CS_HOST			0x80
+#define HCI_LE_SCI			0x01
 
 /* Connection modes */
 #define HCI_CM_ACTIVE	0x0000
@@ -2486,6 +2487,46 @@ struct hci_rp_le_cs_test {
 
 #define HCI_OP_LE_CS_TEST_END			0x2096
 
+#define HCI_OP_LE_CONN_RATE			0x20a1
+struct hci_cp_le_conn_rate {
+	__le16   handle;
+	__le16   interval_min;
+	__le16   interval_max;
+	__le16   subrate_min;
+	__le16   subrate_max;
+	__le16   max_latency;
+	__le16   cont_num;
+	__le16   supv_timeout;
+	__le16   min_ce_len;
+	__le16   max_ce_len;
+} __packed;
+
+#define HCI_OP_LE_SET_DEF_RATE		0x20a2
+struct hci_cp_le_set_def_rate {
+	__le16   interval_min;
+	__le16   interval_max;
+	__le16   subrate_min;
+	__le16   subrate_max;
+	__le16   max_latency;
+	__le16   cont_num;
+	__le16   supv_timeout;
+	__le16   min_ce_len;
+	__le16   max_ce_len;
+} __packed;
+
+#define HCI_OP_LE_READ_CONN_INTERVAL	0x20a3
+struct hci_le_conn_interval_group {
+	__le16   min;
+	__le16   max;
+	__le16   stride;
+} __packed;
+
+struct hci_rp_le_read_conn_interval {
+	__u8    status;
+	__u8    num_grps;
+	struct hci_le_conn_interval_group grps[] __counted_by(num_grps);
+} __packed;
+
 /* ---- HCI Events ---- */
 struct hci_ev_status {
 	__u8    status;
@@ -3300,6 +3341,17 @@ struct hci_evt_le_cs_test_end_complete {
 	__u8	status;
 } __packed;
 
+#define HCI_EVT_LE_CONN_RATE_CHANGE			0x37
+struct hci_evt_le_conn_rate_change {
+	__u8	status;
+	__le16	handle;
+	__le16	interval;
+	__le16	subrate;
+	__le16	latency;
+	__le16	cont_number;
+	__le16	supv_timeout;
+} __packed;
+
 #define HCI_EV_VENDOR			0xff
 
 /* Internal events generated by Bluetooth stack */
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index aa600fbf9a53..61872403fe65 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -333,6 +333,14 @@ struct adv_monitor {
 #define HCI_ADV_MONITOR_EXT_NONE		1
 #define HCI_ADV_MONITOR_EXT_MSFT		2
 
+
+struct sci_group {
+	struct list_head list;
+	__u16 min;
+	__u16 max;
+	__u16 stride;
+};
+
 #define HCI_MAX_SHORT_NAME_LENGTH	10
 
 #define HCI_CONN_HANDLE_MAX		0x0eff
@@ -572,6 +580,7 @@ struct hci_dev {
 	struct list_head	pend_le_reports;
 	struct list_head	blocked_keys;
 	struct list_head	local_codecs;
+	struct list_head	sci_groups;
 
 	struct hci_dev_stats	stat;
 
@@ -2082,6 +2091,12 @@ void hci_conn_del_sysfs(struct hci_conn *conn);
 #define mws_transport_config_capable(dev) (((dev)->commands[30] & 0x08) && \
 	(!hci_test_quirk((dev), HCI_QUIRK_BROKEN_MWS_TRANSPORT_CONFIG)))
 
+/* Shorter Connection Intervals support */
+#define le_sci_capable(dev) \
+	((dev)->le_features[9] & HCI_LE_SCI)
+
+void hci_sci_groups_clear(struct hci_dev *hdev);
+
 /* ----- HCI protocols ----- */
 #define HCI_PROTO_DEFER             0x01
 
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index c46c1236ebfa..04c5559ef029 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2543,8 +2543,9 @@ struct hci_dev *hci_alloc_dev_priv(int sizeof_priv)
 	INIT_LIST_HEAD(&hdev->adv_instances);
 	INIT_LIST_HEAD(&hdev->blocked_keys);
 	INIT_LIST_HEAD(&hdev->monitored_devices);
-
 	INIT_LIST_HEAD(&hdev->local_codecs);
+	INIT_LIST_HEAD(&hdev->sci_groups);
+
 	INIT_WORK(&hdev->rx_work, hci_rx_work);
 	INIT_WORK(&hdev->cmd_work, hci_cmd_work);
 	INIT_WORK(&hdev->tx_work, hci_tx_work);
@@ -2740,6 +2741,16 @@ void hci_unregister_dev(struct hci_dev *hdev)
 }
 EXPORT_SYMBOL(hci_unregister_dev);
 
+void hci_sci_groups_clear(struct hci_dev *hdev)
+{
+	struct sci_group *grp, *tmp;
+
+	list_for_each_entry_safe(grp, tmp, &hdev->sci_groups, list) {
+		list_del(&grp->list);
+		kfree(grp);
+	}
+}
+
 /* Release HCI device */
 void hci_release_dev(struct hci_dev *hdev)
 {
@@ -2766,6 +2777,7 @@ void hci_release_dev(struct hci_dev *hdev)
 	hci_discovery_filter_clear(hdev);
 	hci_blocked_keys_clear(hdev);
 	hci_codec_list_clear(&hdev->local_codecs);
+	hci_sci_groups_clear(hdev);
 	msft_release(hdev);
 	hci_dev_unlock(hdev);
 
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index eea2f810aafa..db2a8d5c456c 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -3957,6 +3957,51 @@ static u8 hci_cc_le_read_all_local_features(struct hci_dev *hdev, void *data,
 	return rp->status;
 }
 
+static u8 hci_cc_le_read_conn_interval(struct hci_dev *hdev, void *data,
+				       struct sk_buff *skb)
+{
+	struct hci_rp_le_read_conn_interval *rp = data;
+	__u8 i;
+
+	bt_dev_dbg(hdev, "status 0x%2.2x", rp->status);
+
+	if (rp->status || !rp->num_grps)
+		return rp->status;
+
+	hci_dev_lock(hdev);
+
+	/* Clear any existing SCI groups before adding new ones. */
+	hci_sci_groups_clear(hdev);
+
+	for (i = 0; i < rp->num_grps; i++) {
+		struct hci_le_conn_interval_group *grp;
+		struct sci_group *sgrp;
+
+		/* Pull HCI event data for the current group. */
+		grp = skb_pull_data(skb, sizeof(*grp));
+		if (!grp) {
+			bt_dev_err(hdev, "invalid data length for SCI group");
+			break;
+		}
+
+		sgrp = kzalloc(sizeof(*sgrp), GFP_KERNEL);
+		if (!sgrp) {
+			bt_dev_err(hdev, "can't allocate memory for SCI group");
+			break;
+		}
+
+		sgrp->min = __le16_to_cpu(grp->min);
+		sgrp->max = __le16_to_cpu(grp->max);
+		sgrp->stride = __le16_to_cpu(grp->stride);
+
+		list_add(&sgrp->list, &hdev->sci_groups);
+	}
+
+	hci_dev_unlock(hdev);
+
+	return rp->status;
+}
+
 static void hci_cs_le_create_big(struct hci_dev *hdev, u8 status)
 {
 	bt_dev_dbg(hdev, "status 0x%2.2x", status);
@@ -4239,6 +4284,10 @@ static const struct hci_cc {
 	HCI_CC(HCI_OP_LE_READ_ALL_LOCAL_FEATURES,
 	       hci_cc_le_read_all_local_features,
 	       sizeof(struct hci_rp_le_read_all_local_features)),
+	HCI_CC_VL(HCI_OP_LE_READ_CONN_INTERVAL,
+		  hci_cc_le_read_conn_interval,
+		  sizeof(struct hci_rp_le_read_conn_interval),
+		  HCI_MAX_EVENT_SIZE),
 };
 
 static u8 hci_cc_func(struct hci_dev *hdev, const struct hci_cc *cc,
@@ -7372,6 +7421,16 @@ static void hci_le_read_all_remote_features_evt(struct hci_dev *hdev,
 	hci_dev_unlock(hdev);
 }
 
+static void hci_le_conn_rate_change_evt(struct hci_dev *hdev, void *data,
+					struct sk_buff *skb)
+{
+	struct hci_evt_le_conn_rate_change *ev = data;
+
+	bt_dev_dbg(hdev, "status 0x%2.2x", ev->status);
+
+	/* TODO: Store rate to be used for next connection? */
+}
+
 #define HCI_LE_EV_VL(_op, _func, _min_len, _max_len) \
 [_op] = { \
 	.func = _func, \
@@ -7483,6 +7542,9 @@ static const struct hci_le_ev {
 		     sizeof(struct
 			    hci_evt_le_read_all_remote_features_complete),
 		     HCI_MAX_EVENT_SIZE),
+	/* [0x37 = HCI_EVT_LE_CONN_RATE_CHANGE] */
+	HCI_LE_EV(HCI_EVT_LE_CONN_RATE_CHANGE, hci_le_conn_rate_change_evt,
+		  sizeof(struct hci_evt_le_conn_rate_change)),
 };
 
 static void hci_le_meta_evt(struct hci_dev *hdev, void *data,
diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index fd3aacdea512..31c3c873e33d 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -4449,6 +4449,10 @@ static int hci_le_set_event_mask_sync(struct hci_dev *hdev)
 		events[6] |= 0x02;	/* LE CS Subevent Result Continue event */
 		events[6] |= 0x04;	/* LE CS Test End Complete event */
 	}
+
+	if (le_sci_capable(hdev))
+		events[6] |= 0x20;	/* LE Connection Rate Change */
+
 	return __hci_cmd_sync_status(hdev, HCI_OP_LE_SET_EVENT_MASK,
 				     sizeof(events), events, HCI_CMD_TIMEOUT);
 }
@@ -4611,9 +4615,16 @@ static int hci_le_set_host_features_sync(struct hci_dev *hdev)
 			return err;
 	}
 
-	if (le_cs_capable(hdev))
+	if (le_cs_capable(hdev)) {
 		/* Channel Sounding (Host Support) */
 		err = hci_le_set_host_feature_sync(hdev, 47, 0x01);
+		if (err)
+			return err;
+	}
+
+	if (le_sci_capable(hdev))
+		/* Short Connection Interval (Host Support) */
+		err = hci_le_set_host_feature_sync(hdev, 73, 0x01);
 
 	return err;
 }
@@ -4896,11 +4907,86 @@ static int hci_le_set_default_phy_sync(struct hci_dev *hdev)
 				     sizeof(cp), &cp, HCI_CMD_TIMEOUT);
 }
 
+/* Read Connection Interval if command is supported and SCI feature bit is
+ * marked as supported.
+ */
+static int hci_le_read_conn_interval_sync(struct hci_dev *hdev)
+{
+	if (!(hdev->commands[48] & BIT(7)) || !le_sci_capable(hdev))
+		return 0;
+
+	return __hci_cmd_sync_status(hdev, HCI_OP_LE_READ_CONN_INTERVAL,
+				     0, NULL, HCI_CMD_TIMEOUT);
+}
+
+/* Set Default Connection Rate Parameters if command is supported, SCI feature
+ * bit is marked as supported and at least one of the supported SCI groups
+ * exists.
+ */
+static int hci_le_set_def_rate_sync(struct hci_dev *hdev)
+{
+	struct hci_cp_le_set_def_rate cp;
+	struct sci_group *grp, *tmp;
+	__u16 min = 0, max = 0;
+
+	if (!(hdev->commands[48] & BIT(6)) || !le_sci_capable(hdev) ||
+	    list_empty(&hdev->sci_groups))
+		return 0;
+
+	memset(&cp, 0, sizeof(cp));
+
+	/* Iterate over the SCI groups and find the widest supported connection
+	 * interval range to maximize compatibility with peer devices.
+	 */
+	list_for_each_entry_safe(grp, tmp, &hdev->sci_groups, list) {
+		if (!min == 0 || grp->min < min)
+			min = grp->min;
+
+		if (!max == 0 || grp->max > max)
+			max = grp->max;
+	}
+
+	cp.interval_min = cpu_to_le16(min);
+	cp.interval_max = cpu_to_le16(max);
+
+	/* HOG 1.2 Table 7.4. Modes with recommended parameter values suggests
+	 * subrate 1-4 for all modes so use that as default.
+	 */
+	cp.subrate_min = cpu_to_le16(0x0001);
+	cp.subrate_max = cpu_to_le16(0x0004);
+
+	/* HIP 1.2 Table 7.5. Modes with recommended parameter values suggests
+	 * max latency of 0 for all modes expect low power.
+	 */
+	cp.max_latency = 0x0000;
+
+	/* HIP 1.2 Table 7.5. Modes with recommended parameter values suggests
+	 * continuation number 1 for full range.
+	 */
+	cp.cont_num = cpu_to_le16(0x0001);
+
+	/* HOG 1.2 Table 7.4. Modes with recommended parameter values states
+	 * that link supervision timeout should be: Greater than or equal to
+	 * (1 + Peripheral Latency) x Subrate max x Connection Interval max x 2.
+	 */
+	cp.supv_timeout = cpu_to_le16((1 + 0) * 0x0004 * max * 2 / 10);
+
+	cp.min_ce_len = cpu_to_le16(min);
+	cp.max_ce_len = cpu_to_le16(max);
+
+	return __hci_cmd_sync_status(hdev, HCI_OP_LE_SET_DEF_RATE,
+				     sizeof(cp), &cp, HCI_CMD_TIMEOUT);
+}
+
 static const struct hci_init_stage le_init4[] = {
 	/* HCI_OP_LE_WRITE_DEF_DATA_LEN */
 	HCI_INIT(hci_le_set_write_def_data_len_sync),
 	/* HCI_OP_LE_SET_DEFAULT_PHY */
 	HCI_INIT(hci_le_set_default_phy_sync),
+	/* HCI_OP_LE_READ_CONN_INTERVAL */
+	HCI_INIT(hci_le_read_conn_interval_sync),
+	/* HCI_OP_LE_SET_DEF_RATE */
+	HCI_INIT(hci_le_set_def_rate_sync),
 	{}
 };
 
-- 
2.53.0


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2026-05-06 16:06 [PATCH v2 1/2] Bluetooth: HCI: Add initial support for Short Connection Interval feature Luiz Augusto von Dentz
2026-05-06 16:06 ` [PATCH v2 2/2] Bluetooth: MGMT: Add SCI setting bit(25) Luiz Augusto von Dentz
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