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67d2f8781b
Commit dec2c92880 ("Bluetooth: hci_ldisc:
Use rwlocking to avoid closing proto races") introduced locks in
hci_ldisc that are held while calling the proto functions. These locks
are rwlock's, and hence do not allow sleeping while they are held.
However, the proto functions that hci_bcm registers use mutexes and
hence need to be able to sleep.
In more detail: hci_uart_tty_receive() and hci_uart_dequeue() both
acquire the rwlock, after which they call proto->recv() and
proto->dequeue(), respectively. In the case of hci_bcm these point to
bcm_recv() and bcm_dequeue(). The latter both acquire the
bcm_device_lock, which is a mutex, so doing so results in a call to
might_sleep(). But since we're holding a rwlock in hci_ldisc, that
results in the following BUG (this for the dequeue case - a similar
one for the receive case is omitted for brevity):
BUG: sleeping function called from invalid context at kernel/locking/mutex.c
in_atomic(): 1, irqs_disabled(): 0, pid: 7303, name: kworker/7:3
INFO: lockdep is turned off.
CPU: 7 PID: 7303 Comm: kworker/7:3 Tainted: G W OE 4.13.2+ #17
Hardware name: Apple Inc. MacBookPro13,3/Mac-A5C67F76ED83108C, BIOS MBP133.8
Workqueue: events hci_uart_write_work [hci_uart]
Call Trace:
dump_stack+0x8e/0xd6
___might_sleep+0x164/0x250
__might_sleep+0x4a/0x80
__mutex_lock+0x59/0xa00
? lock_acquire+0xa3/0x1f0
? lock_acquire+0xa3/0x1f0
? hci_uart_write_work+0xd3/0x160 [hci_uart]
mutex_lock_nested+0x1b/0x20
? mutex_lock_nested+0x1b/0x20
bcm_dequeue+0x21/0xc0 [hci_uart]
hci_uart_write_work+0xe6/0x160 [hci_uart]
process_one_work+0x253/0x6a0
worker_thread+0x4d/0x3b0
kthread+0x133/0x150
We can't replace the mutex in hci_bcm, because there are other calls
there that might sleep. Therefore this replaces the rwlock's in
hci_ldisc with rw_semaphore's (which allow sleeping). This is a safer
approach anyway as it reduces the restrictions on the proto callbacks.
Also, because acquiring write-lock is very rare compared to acquiring
the read-lock, the percpu variant of rw_semaphore is used.
Lastly, because hci_uart_tx_wakeup() may be called from an IRQ context,
we can't block (sleep) while trying acquire the read lock there, so we
use the trylock variant.
Signed-off-by: Ronald Tschalär <ronald@innovation.ch>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
207 lines
5.1 KiB
C
207 lines
5.1 KiB
C
/*
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*
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* Bluetooth HCI UART driver
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*
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* Copyright (C) 2000-2001 Qualcomm Incorporated
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* Copyright (C) 2002-2003 Maxim Krasnyansky <maxk@qualcomm.com>
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* Copyright (C) 2004-2005 Marcel Holtmann <marcel@holtmann.org>
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*
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#ifndef N_HCI
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#define N_HCI 15
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#endif
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/* Ioctls */
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#define HCIUARTSETPROTO _IOW('U', 200, int)
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#define HCIUARTGETPROTO _IOR('U', 201, int)
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#define HCIUARTGETDEVICE _IOR('U', 202, int)
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#define HCIUARTSETFLAGS _IOW('U', 203, int)
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#define HCIUARTGETFLAGS _IOR('U', 204, int)
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/* UART protocols */
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#define HCI_UART_MAX_PROTO 12
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#define HCI_UART_H4 0
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#define HCI_UART_BCSP 1
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#define HCI_UART_3WIRE 2
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#define HCI_UART_H4DS 3
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#define HCI_UART_LL 4
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#define HCI_UART_ATH3K 5
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#define HCI_UART_INTEL 6
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#define HCI_UART_BCM 7
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#define HCI_UART_QCA 8
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#define HCI_UART_AG6XX 9
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#define HCI_UART_NOKIA 10
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#define HCI_UART_MRVL 11
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#define HCI_UART_RAW_DEVICE 0
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#define HCI_UART_RESET_ON_INIT 1
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#define HCI_UART_CREATE_AMP 2
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#define HCI_UART_INIT_PENDING 3
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#define HCI_UART_EXT_CONFIG 4
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#define HCI_UART_VND_DETECT 5
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struct hci_uart;
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struct serdev_device;
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struct hci_uart_proto {
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unsigned int id;
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const char *name;
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unsigned int manufacturer;
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unsigned int init_speed;
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unsigned int oper_speed;
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int (*open)(struct hci_uart *hu);
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int (*close)(struct hci_uart *hu);
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int (*flush)(struct hci_uart *hu);
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int (*setup)(struct hci_uart *hu);
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int (*set_baudrate)(struct hci_uart *hu, unsigned int speed);
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int (*recv)(struct hci_uart *hu, const void *data, int len);
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int (*enqueue)(struct hci_uart *hu, struct sk_buff *skb);
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struct sk_buff *(*dequeue)(struct hci_uart *hu);
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};
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struct hci_uart {
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struct tty_struct *tty;
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struct serdev_device *serdev;
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struct hci_dev *hdev;
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unsigned long flags;
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unsigned long hdev_flags;
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struct work_struct init_ready;
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struct work_struct write_work;
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const struct hci_uart_proto *proto;
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struct percpu_rw_semaphore proto_lock; /* Stop work for proto close */
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void *priv;
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struct sk_buff *tx_skb;
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unsigned long tx_state;
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unsigned int init_speed;
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unsigned int oper_speed;
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u8 alignment;
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u8 padding;
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};
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/* HCI_UART proto flag bits */
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#define HCI_UART_PROTO_SET 0
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#define HCI_UART_REGISTERED 1
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#define HCI_UART_PROTO_READY 2
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/* TX states */
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#define HCI_UART_SENDING 1
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#define HCI_UART_TX_WAKEUP 2
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int hci_uart_register_proto(const struct hci_uart_proto *p);
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int hci_uart_unregister_proto(const struct hci_uart_proto *p);
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int hci_uart_register_device(struct hci_uart *hu, const struct hci_uart_proto *p);
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void hci_uart_unregister_device(struct hci_uart *hu);
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int hci_uart_tx_wakeup(struct hci_uart *hu);
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int hci_uart_init_ready(struct hci_uart *hu);
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void hci_uart_set_baudrate(struct hci_uart *hu, unsigned int speed);
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void hci_uart_set_flow_control(struct hci_uart *hu, bool enable);
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void hci_uart_set_speeds(struct hci_uart *hu, unsigned int init_speed,
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unsigned int oper_speed);
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#ifdef CONFIG_BT_HCIUART_H4
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int h4_init(void);
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int h4_deinit(void);
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struct h4_recv_pkt {
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u8 type; /* Packet type */
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u8 hlen; /* Header length */
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u8 loff; /* Data length offset in header */
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u8 lsize; /* Data length field size */
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u16 maxlen; /* Max overall packet length */
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int (*recv)(struct hci_dev *hdev, struct sk_buff *skb);
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};
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#define H4_RECV_ACL \
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.type = HCI_ACLDATA_PKT, \
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.hlen = HCI_ACL_HDR_SIZE, \
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.loff = 2, \
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.lsize = 2, \
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.maxlen = HCI_MAX_FRAME_SIZE \
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#define H4_RECV_SCO \
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.type = HCI_SCODATA_PKT, \
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.hlen = HCI_SCO_HDR_SIZE, \
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.loff = 2, \
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.lsize = 1, \
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.maxlen = HCI_MAX_SCO_SIZE
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#define H4_RECV_EVENT \
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.type = HCI_EVENT_PKT, \
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.hlen = HCI_EVENT_HDR_SIZE, \
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.loff = 1, \
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.lsize = 1, \
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.maxlen = HCI_MAX_EVENT_SIZE
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struct sk_buff *h4_recv_buf(struct hci_dev *hdev, struct sk_buff *skb,
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const unsigned char *buffer, int count,
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const struct h4_recv_pkt *pkts, int pkts_count);
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#endif
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#ifdef CONFIG_BT_HCIUART_BCSP
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int bcsp_init(void);
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int bcsp_deinit(void);
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#endif
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#ifdef CONFIG_BT_HCIUART_LL
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int ll_init(void);
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int ll_deinit(void);
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#endif
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#ifdef CONFIG_BT_HCIUART_ATH3K
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int ath_init(void);
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int ath_deinit(void);
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#endif
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#ifdef CONFIG_BT_HCIUART_3WIRE
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int h5_init(void);
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int h5_deinit(void);
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#endif
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#ifdef CONFIG_BT_HCIUART_INTEL
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int intel_init(void);
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int intel_deinit(void);
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#endif
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#ifdef CONFIG_BT_HCIUART_BCM
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int bcm_init(void);
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int bcm_deinit(void);
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#endif
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#ifdef CONFIG_BT_HCIUART_QCA
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int qca_init(void);
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int qca_deinit(void);
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#endif
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#ifdef CONFIG_BT_HCIUART_AG6XX
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int ag6xx_init(void);
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int ag6xx_deinit(void);
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#endif
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#ifdef CONFIG_BT_HCIUART_MRVL
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int mrvl_init(void);
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int mrvl_deinit(void);
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#endif
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