Bluetooth: hci_event: Add quirk to ignore byte in LE Extended Adv Report

Broadcom controllers present on Apple Silicon devices use the upper
8 bits of the event type in the LE Extended Advertising Report for
the channel on which the frame has been received.
Add a quirk to drop the upper byte to ensure that the advertising
results are parsed correctly.

The following except from a btmon trace shows a report received on
channel 37 by these controllers:

> HCI Event: LE Meta Event (0x3e) plen 55                    #1 [hci0] 0.912271
      LE Extended Advertising Report (0x0d)
        Num reports: 1
        Entry 0
          Event type: 0x2513
            Props: 0x0013
              Connectable
              Scannable
              Use legacy advertising PDUs
            Data status: Complete
            Reserved (0x2500)
          Legacy PDU Type: Reserved (0x2513)
          Address type: Public (0x00)
          Address: XX:XX:XX:XX:XX:XX (Shenzhen Jingxun Software Telecommunication Technology Co.,Ltd)
          Primary PHY: LE 1M
          Secondary PHY: No packets
          SID: no ADI field (0xff)
          TX power: 127 dBm
          RSSI: -76 dBm (0xb4)
          Periodic advertising interval: 0.00 msec (0x0000)
          Direct address type: Public (0x00)
          Direct address: 00:00:00:00:00:00 (OUI 00-00-00)
          Data length: 0x1d
        02 01 18 09 ff 57 00 31 1f 01 3c 86 ab 03 16 df  .....W.1..<.....
        fd 0b 09 4a 42 4c 20 46 6c 69 70 20 35           ...JBL Flip 5
        Flags: 0x18
          Simultaneous LE and BR/EDR (Controller)
          Simultaneous LE and BR/EDR (Host)
        Company: Harman International Industries, Inc. (87)
          Data: 311f013c86ab
        Service Data (UUID 0xfddf):
        Name (complete): JBL Flip 5

Signed-off-by: Sven Peter <sven@svenpeter.dev>

Author: svenpeter42

include/net/bluetooth/hci.h

@@ -263,6 +263,17 @@ enum {
 	 * during the hdev->setup vendor callback.
 	 */
 	HCI_QUIRK_BROKEN_ENHANCED_SETUP_SYNC_CONN,
+
+	/*
+	 * When this quirk is set, the upper 8 bits of the evt_type field of
+	 * the LE Extended Advertising Report events are discarded.
+	 * Some Broadcom controllers found in Apple machines put the channel
+	 * the report was received on into these reserved bits.
+	 *
+	 * This quirk can be set before hci_register_dev is called or
+	 * during the hdev->setup vendor callback.
+	 */
+	HCI_QUIRK_FIXUP_LE_EXT_ADV_REPORT_EVT_TYPE,
 };
 
 /* HCI device flags */

net/bluetooth/hci_event.c

@@ -6471,6 +6471,10 @@ static void hci_le_ext_adv_report_evt(struct hci_dev *hdev, void *data,
 			break;
 
 		evt_type = __le16_to_cpu(info->type);
+		if (test_bit(HCI_QUIRK_FIXUP_LE_EXT_ADV_REPORT_EVT_TYPE,
+			     &hdev->quirks))
+			evt_type &= 0xff;
+
 		legacy_evt_type = ext_evt_type_to_legacy(hdev, evt_type);
 		if (legacy_evt_type != LE_ADV_INVALID) {
 			process_adv_report(hdev, legacy_evt_type, &info->bdaddr,