[PATCH v4 4/5] Bluetooth: Query LE tx power on startup

From: Daniel Winkler
Date: Thu Oct 01 2020 - 19:04:22 EST


Queries tx power via HCI_LE_Read_Transmit_Power command when the hci
device is initialized, and stores resulting min/max LE power in hdev
struct. If command isn't available (< BT5 support), min/max values
both default to HCI_TX_POWER_INVALID.

This patch is manually verified by ensuring BT5 devices correctly query
and receive controller tx power range.

Reviewed-by: Sonny Sasaka <sonnysasaka@xxxxxxxxxxxx>
Signed-off-by: Daniel Winkler <danielwinkler@xxxxxxxxxx>
---

Changes in v4: None
Changes in v3: None
Changes in v2: None

include/net/bluetooth/hci.h | 7 +++++++
include/net/bluetooth/hci_core.h | 2 ++
net/bluetooth/hci_core.c | 8 ++++++++
net/bluetooth/hci_event.c | 18 ++++++++++++++++++
4 files changed, 35 insertions(+)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index c8e67042a3b14c..c1504aa3d9cfd5 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -1797,6 +1797,13 @@ struct hci_cp_le_set_adv_set_rand_addr {
bdaddr_t bdaddr;
} __packed;

+#define HCI_OP_LE_READ_TRANSMIT_POWER 0x204b
+struct hci_rp_le_read_transmit_power {
+ __u8 status;
+ __s8 min_le_tx_power;
+ __s8 max_le_tx_power;
+} __packed;
+
#define HCI_OP_LE_READ_BUFFER_SIZE_V2 0x2060
struct hci_rp_le_read_buffer_size_v2 {
__u8 status;
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index ab168f46b6d909..9463039f85442c 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -381,6 +381,8 @@ struct hci_dev {
__u16 def_page_timeout;
__u16 def_multi_adv_rotation_duration;
__u16 def_le_autoconnect_timeout;
+ __s8 min_le_tx_power;
+ __s8 max_le_tx_power;

__u16 pkt_type;
__u16 esco_type;
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 3a2332f4a9bba2..6bff1c09be3b42 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -741,6 +741,12 @@ static int hci_init3_req(struct hci_request *req, unsigned long opt)
hci_req_add(req, HCI_OP_LE_READ_ADV_TX_POWER, 0, NULL);
}

+ if (hdev->commands[38] & 0x80) {
+ /* Read LE Min/Max Tx Power*/
+ hci_req_add(req, HCI_OP_LE_READ_TRANSMIT_POWER,
+ 0, NULL);
+ }
+
if (hdev->commands[26] & 0x40) {
/* Read LE White List Size */
hci_req_add(req, HCI_OP_LE_READ_WHITE_LIST_SIZE,
@@ -3654,6 +3660,8 @@ struct hci_dev *hci_alloc_dev(void)
hdev->le_num_of_adv_sets = HCI_MAX_ADV_INSTANCES;
hdev->def_multi_adv_rotation_duration = HCI_DEFAULT_ADV_DURATION;
hdev->def_le_autoconnect_timeout = HCI_LE_AUTOCONN_TIMEOUT;
+ hdev->min_le_tx_power = HCI_TX_POWER_INVALID;
+ hdev->max_le_tx_power = HCI_TX_POWER_INVALID;

hdev->rpa_timeout = HCI_DEFAULT_RPA_TIMEOUT;
hdev->discov_interleaved_timeout = DISCOV_INTERLEAVED_TIMEOUT;
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 4281f4ac6700d4..de51188a3dc15d 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -1202,6 +1202,20 @@ static void hci_cc_le_set_adv_set_random_addr(struct hci_dev *hdev,
hci_dev_unlock(hdev);
}

+static void hci_cc_le_read_transmit_power(struct hci_dev *hdev,
+ struct sk_buff *skb)
+{
+ struct hci_rp_le_read_transmit_power *rp = (void *)skb->data;
+
+ BT_DBG("%s status 0x%2.2x", hdev->name, rp->status);
+
+ if (rp->status)
+ return;
+
+ hdev->min_le_tx_power = rp->min_le_tx_power;
+ hdev->max_le_tx_power = rp->max_le_tx_power;
+}
+
static void hci_cc_le_set_adv_enable(struct hci_dev *hdev, struct sk_buff *skb)
{
__u8 *sent, status = *((__u8 *) skb->data);
@@ -3574,6 +3588,10 @@ static void hci_cmd_complete_evt(struct hci_dev *hdev, struct sk_buff *skb,
hci_cc_le_set_adv_set_random_addr(hdev, skb);
break;

+ case HCI_OP_LE_READ_TRANSMIT_POWER:
+ hci_cc_le_read_transmit_power(hdev, skb);
+ break;
+
default:
BT_DBG("%s opcode 0x%4.4x", hdev->name, *opcode);
break;
--
2.28.0.709.gb0816b6eb0-goog