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path: root/drivers/bluetooth/hci_h5.c
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Diffstat (limited to 'drivers/bluetooth/hci_h5.c')
-rw-r--r--drivers/bluetooth/hci_h5.c747
1 files changed, 747 insertions, 0 deletions
diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c
new file mode 100644
index 000000000000..b6154d5a07a5
--- /dev/null
+++ b/drivers/bluetooth/hci_h5.c
@@ -0,0 +1,747 @@
+/*
+ *
+ * Bluetooth HCI Three-wire UART driver
+ *
+ * Copyright (C) 2012 Intel Corporation
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+
+#include "hci_uart.h"
+
+#define HCI_3WIRE_ACK_PKT 0
+#define HCI_3WIRE_LINK_PKT 15
+
+/* Sliding window size */
+#define H5_TX_WIN_MAX 4
+
+#define H5_ACK_TIMEOUT msecs_to_jiffies(250)
+#define H5_SYNC_TIMEOUT msecs_to_jiffies(100)
+
+/*
+ * Maximum Three-wire packet:
+ * 4 byte header + max value for 12-bit length + 2 bytes for CRC
+ */
+#define H5_MAX_LEN (4 + 0xfff + 2)
+
+/* Convenience macros for reading Three-wire header values */
+#define H5_HDR_SEQ(hdr) ((hdr)[0] & 0x07)
+#define H5_HDR_ACK(hdr) (((hdr)[0] >> 3) & 0x07)
+#define H5_HDR_CRC(hdr) (((hdr)[0] >> 6) & 0x01)
+#define H5_HDR_RELIABLE(hdr) (((hdr)[0] >> 7) & 0x01)
+#define H5_HDR_PKT_TYPE(hdr) ((hdr)[1] & 0x0f)
+#define H5_HDR_LEN(hdr) ((((hdr)[1] >> 4) & 0xff) + ((hdr)[2] << 4))
+
+#define SLIP_DELIMITER 0xc0
+#define SLIP_ESC 0xdb
+#define SLIP_ESC_DELIM 0xdc
+#define SLIP_ESC_ESC 0xdd
+
+/* H5 state flags */
+enum {
+ H5_RX_ESC, /* SLIP escape mode */
+ H5_TX_ACK_REQ, /* Pending ack to send */
+};
+
+struct h5 {
+ struct sk_buff_head unack; /* Unack'ed packets queue */
+ struct sk_buff_head rel; /* Reliable packets queue */
+ struct sk_buff_head unrel; /* Unreliable packets queue */
+
+ unsigned long flags;
+
+ struct sk_buff *rx_skb; /* Receive buffer */
+ size_t rx_pending; /* Expecting more bytes */
+ u8 rx_ack; /* Last ack number received */
+
+ int (*rx_func) (struct hci_uart *hu, u8 c);
+
+ struct timer_list timer; /* Retransmission timer */
+
+ u8 tx_seq; /* Next seq number to send */
+ u8 tx_ack; /* Next ack number to send */
+ u8 tx_win; /* Sliding window size */
+
+ enum {
+ H5_UNINITIALIZED,
+ H5_INITIALIZED,
+ H5_ACTIVE,
+ } state;
+
+ enum {
+ H5_AWAKE,
+ H5_SLEEPING,
+ H5_WAKING_UP,
+ } sleep;
+};
+
+static void h5_reset_rx(struct h5 *h5);
+
+static void h5_link_control(struct hci_uart *hu, const void *data, size_t len)
+{
+ struct h5 *h5 = hu->priv;
+ struct sk_buff *nskb;
+
+ nskb = alloc_skb(3, GFP_ATOMIC);
+ if (!nskb)
+ return;
+
+ bt_cb(nskb)->pkt_type = HCI_3WIRE_LINK_PKT;
+
+ memcpy(skb_put(nskb, len), data, len);
+
+ skb_queue_tail(&h5->unrel, nskb);
+}
+
+static u8 h5_cfg_field(struct h5 *h5)
+{
+ u8 field = 0;
+
+ /* Sliding window size (first 3 bits) */
+ field |= (h5->tx_win & 7);
+
+ return field;
+}
+
+static void h5_timed_event(unsigned long arg)
+{
+ const unsigned char sync_req[] = { 0x01, 0x7e };
+ unsigned char conf_req[] = { 0x03, 0xfc, 0x01 };
+ struct hci_uart *hu = (struct hci_uart *) arg;
+ struct h5 *h5 = hu->priv;
+ struct sk_buff *skb;
+ unsigned long flags;
+
+ BT_DBG("%s", hu->hdev->name);
+
+ if (h5->state == H5_UNINITIALIZED)
+ h5_link_control(hu, sync_req, sizeof(sync_req));
+
+ if (h5->state == H5_INITIALIZED) {
+ conf_req[2] = h5_cfg_field(h5);
+ h5_link_control(hu, conf_req, sizeof(conf_req));
+ }
+
+ if (h5->state != H5_ACTIVE) {
+ mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
+ goto wakeup;
+ }
+
+ if (h5->sleep != H5_AWAKE) {
+ h5->sleep = H5_SLEEPING;
+ goto wakeup;
+ }
+
+ BT_DBG("hu %p retransmitting %u pkts", hu, h5->unack.qlen);
+
+ spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
+
+ while ((skb = __skb_dequeue_tail(&h5->unack)) != NULL) {
+ h5->tx_seq = (h5->tx_seq - 1) & 0x07;
+ skb_queue_head(&h5->rel, skb);
+ }
+
+ spin_unlock_irqrestore(&h5->unack.lock, flags);
+
+wakeup:
+ hci_uart_tx_wakeup(hu);
+}
+
+static int h5_open(struct hci_uart *hu)
+{
+ struct h5 *h5;
+ const unsigned char sync[] = { 0x01, 0x7e };
+
+ BT_DBG("hu %p", hu);
+
+ h5 = kzalloc(sizeof(*h5), GFP_KERNEL);
+ if (!h5)
+ return -ENOMEM;
+
+ hu->priv = h5;
+
+ skb_queue_head_init(&h5->unack);
+ skb_queue_head_init(&h5->rel);
+ skb_queue_head_init(&h5->unrel);
+
+ h5_reset_rx(h5);
+
+ init_timer(&h5->timer);
+ h5->timer.function = h5_timed_event;
+ h5->timer.data = (unsigned long) hu;
+
+ h5->tx_win = H5_TX_WIN_MAX;
+
+ set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags);
+
+ /* Send initial sync request */
+ h5_link_control(hu, sync, sizeof(sync));
+ mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
+
+ return 0;
+}
+
+static int h5_close(struct hci_uart *hu)
+{
+ struct h5 *h5 = hu->priv;
+
+ skb_queue_purge(&h5->unack);
+ skb_queue_purge(&h5->rel);
+ skb_queue_purge(&h5->unrel);
+
+ del_timer(&h5->timer);
+
+ kfree(h5);
+
+ return 0;
+}
+
+static void h5_pkt_cull(struct h5 *h5)
+{
+ struct sk_buff *skb, *tmp;
+ unsigned long flags;
+ int i, to_remove;
+ u8 seq;
+
+ spin_lock_irqsave(&h5->unack.lock, flags);
+
+ to_remove = skb_queue_len(&h5->unack);
+ if (to_remove == 0)
+ goto unlock;
+
+ seq = h5->tx_seq;
+
+ while (to_remove > 0) {
+ if (h5->rx_ack == seq)
+ break;
+
+ to_remove--;
+ seq = (seq - 1) % 8;
+ }
+
+ if (seq != h5->rx_ack)
+ BT_ERR("Controller acked invalid packet");
+
+ i = 0;
+ skb_queue_walk_safe(&h5->unack, skb, tmp) {
+ if (i++ >= to_remove)
+ break;
+
+ __skb_unlink(skb, &h5->unack);
+ kfree_skb(skb);
+ }
+
+ if (skb_queue_empty(&h5->unack))
+ del_timer(&h5->timer);
+
+unlock:
+ spin_unlock_irqrestore(&h5->unack.lock, flags);
+}
+
+static void h5_handle_internal_rx(struct hci_uart *hu)
+{
+ struct h5 *h5 = hu->priv;
+ const unsigned char sync_req[] = { 0x01, 0x7e };
+ const unsigned char sync_rsp[] = { 0x02, 0x7d };
+ unsigned char conf_req[] = { 0x03, 0xfc, 0x01 };
+ const unsigned char conf_rsp[] = { 0x04, 0x7b };
+ const unsigned char wakeup_req[] = { 0x05, 0xfa };
+ const unsigned char woken_req[] = { 0x06, 0xf9 };
+ const unsigned char sleep_req[] = { 0x07, 0x78 };
+ const unsigned char *hdr = h5->rx_skb->data;
+ const unsigned char *data = &h5->rx_skb->data[4];
+
+ BT_DBG("%s", hu->hdev->name);
+
+ if (H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT)
+ return;
+
+ if (H5_HDR_LEN(hdr) < 2)
+ return;
+
+ conf_req[2] = h5_cfg_field(h5);
+
+ if (memcmp(data, sync_req, 2) == 0) {
+ h5_link_control(hu, sync_rsp, 2);
+ } else if (memcmp(data, sync_rsp, 2) == 0) {
+ h5->state = H5_INITIALIZED;
+ h5_link_control(hu, conf_req, 3);
+ } else if (memcmp(data, conf_req, 2) == 0) {
+ h5_link_control(hu, conf_rsp, 2);
+ h5_link_control(hu, conf_req, 3);
+ } else if (memcmp(data, conf_rsp, 2) == 0) {
+ if (H5_HDR_LEN(hdr) > 2)
+ h5->tx_win = (data[2] & 7);
+ BT_DBG("Three-wire init complete. tx_win %u", h5->tx_win);
+ h5->state = H5_ACTIVE;
+ hci_uart_init_ready(hu);
+ return;
+ } else if (memcmp(data, sleep_req, 2) == 0) {
+ BT_DBG("Peer went to sleep");
+ h5->sleep = H5_SLEEPING;
+ return;
+ } else if (memcmp(data, woken_req, 2) == 0) {
+ BT_DBG("Peer woke up");
+ h5->sleep = H5_AWAKE;
+ } else if (memcmp(data, wakeup_req, 2) == 0) {
+ BT_DBG("Peer requested wakeup");
+ h5_link_control(hu, woken_req, 2);
+ h5->sleep = H5_AWAKE;
+ } else {
+ BT_DBG("Link Control: 0x%02hhx 0x%02hhx", data[0], data[1]);
+ return;
+ }
+
+ hci_uart_tx_wakeup(hu);
+}
+
+static void h5_complete_rx_pkt(struct hci_uart *hu)
+{
+ struct h5 *h5 = hu->priv;
+ const unsigned char *hdr = h5->rx_skb->data;
+
+ if (H5_HDR_RELIABLE(hdr)) {
+ h5->tx_ack = (h5->tx_ack + 1) % 8;
+ set_bit(H5_TX_ACK_REQ, &h5->flags);
+ hci_uart_tx_wakeup(hu);
+ }
+
+ h5->rx_ack = H5_HDR_ACK(hdr);
+
+ h5_pkt_cull(h5);
+
+ switch (H5_HDR_PKT_TYPE(hdr)) {
+ case HCI_EVENT_PKT:
+ case HCI_ACLDATA_PKT:
+ case HCI_SCODATA_PKT:
+ bt_cb(h5->rx_skb)->pkt_type = H5_HDR_PKT_TYPE(hdr);
+
+ /* Remove Three-wire header */
+ skb_pull(h5->rx_skb, 4);
+
+ hci_recv_frame(h5->rx_skb);
+ h5->rx_skb = NULL;
+
+ break;
+
+ default:
+ h5_handle_internal_rx(hu);
+ break;
+ }
+
+ h5_reset_rx(h5);
+}
+
+static int h5_rx_crc(struct hci_uart *hu, unsigned char c)
+{
+ struct h5 *h5 = hu->priv;
+
+ h5_complete_rx_pkt(hu);
+ h5_reset_rx(h5);
+
+ return 0;
+}
+
+static int h5_rx_payload(struct hci_uart *hu, unsigned char c)
+{
+ struct h5 *h5 = hu->priv;
+ const unsigned char *hdr = h5->rx_skb->data;
+
+ if (H5_HDR_CRC(hdr)) {
+ h5->rx_func = h5_rx_crc;
+ h5->rx_pending = 2;
+ } else {
+ h5_complete_rx_pkt(hu);
+ h5_reset_rx(h5);
+ }
+
+ return 0;
+}
+
+static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c)
+{
+ struct h5 *h5 = hu->priv;
+ const unsigned char *hdr = h5->rx_skb->data;
+
+ BT_DBG("%s rx: seq %u ack %u crc %u rel %u type %u len %u",
+ hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
+ H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
+ H5_HDR_LEN(hdr));
+
+ if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) {
+ BT_ERR("Invalid header checksum");
+ h5_reset_rx(h5);
+ return 0;
+ }
+
+ if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_ack) {
+ BT_ERR("Out-of-order packet arrived (%u != %u)",
+ H5_HDR_SEQ(hdr), h5->tx_ack);
+ h5_reset_rx(h5);
+ return 0;
+ }
+
+ if (h5->state != H5_ACTIVE &&
+ H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT) {
+ BT_ERR("Non-link packet received in non-active state");
+ h5_reset_rx(h5);
+ }
+
+ h5->rx_func = h5_rx_payload;
+ h5->rx_pending = H5_HDR_LEN(hdr);
+
+ return 0;
+}
+
+static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c)
+{
+ struct h5 *h5 = hu->priv;
+
+ if (c == SLIP_DELIMITER)
+ return 1;
+
+ h5->rx_func = h5_rx_3wire_hdr;
+ h5->rx_pending = 4;
+
+ h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC);
+ if (!h5->rx_skb) {
+ BT_ERR("Can't allocate mem for new packet");
+ h5_reset_rx(h5);
+ return -ENOMEM;
+ }
+
+ h5->rx_skb->dev = (void *) hu->hdev;
+
+ return 0;
+}
+
+static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c)
+{
+ struct h5 *h5 = hu->priv;
+
+ if (c == SLIP_DELIMITER)
+ h5->rx_func = h5_rx_pkt_start;
+
+ return 1;
+}
+
+static void h5_unslip_one_byte(struct h5 *h5, unsigned char c)
+{
+ const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC;
+ const u8 *byte = &c;
+
+ if (!test_bit(H5_RX_ESC, &h5->flags) && c == SLIP_ESC) {
+ set_bit(H5_RX_ESC, &h5->flags);
+ return;
+ }
+
+ if (test_and_clear_bit(H5_RX_ESC, &h5->flags)) {
+ switch (c) {
+ case SLIP_ESC_DELIM:
+ byte = &delim;
+ break;
+ case SLIP_ESC_ESC:
+ byte = &esc;
+ break;
+ default:
+ BT_ERR("Invalid esc byte 0x%02hhx", c);
+ h5_reset_rx(h5);
+ return;
+ }
+ }
+
+ memcpy(skb_put(h5->rx_skb, 1), byte, 1);
+ h5->rx_pending--;
+
+ BT_DBG("unsliped 0x%02hhx, rx_pending %zu", *byte, h5->rx_pending);
+}
+
+static void h5_reset_rx(struct h5 *h5)
+{
+ if (h5->rx_skb) {
+ kfree_skb(h5->rx_skb);
+ h5->rx_skb = NULL;
+ }
+
+ h5->rx_func = h5_rx_delimiter;
+ h5->rx_pending = 0;
+ clear_bit(H5_RX_ESC, &h5->flags);
+}
+
+static int h5_recv(struct hci_uart *hu, void *data, int count)
+{
+ struct h5 *h5 = hu->priv;
+ unsigned char *ptr = data;
+
+ BT_DBG("%s pending %zu count %d", hu->hdev->name, h5->rx_pending,
+ count);
+
+ while (count > 0) {
+ int processed;
+
+ if (h5->rx_pending > 0) {
+ if (*ptr == SLIP_DELIMITER) {
+ BT_ERR("Too short H5 packet");
+ h5_reset_rx(h5);
+ continue;
+ }
+
+ h5_unslip_one_byte(h5, *ptr);
+
+ ptr++; count--;
+ continue;
+ }
+
+ processed = h5->rx_func(hu, *ptr);
+ if (processed < 0)
+ return processed;
+
+ ptr += processed;
+ count -= processed;
+ }
+
+ return 0;
+}
+
+static int h5_enqueue(struct hci_uart *hu, struct sk_buff *skb)
+{
+ struct h5 *h5 = hu->priv;
+
+ if (skb->len > 0xfff) {
+ BT_ERR("Packet too long (%u bytes)", skb->len);
+ kfree_skb(skb);
+ return 0;
+ }
+
+ if (h5->state != H5_ACTIVE) {
+ BT_ERR("Ignoring HCI data in non-active state");
+ kfree_skb(skb);
+ return 0;
+ }
+
+ switch (bt_cb(skb)->pkt_type) {
+ case HCI_ACLDATA_PKT:
+ case HCI_COMMAND_PKT:
+ skb_queue_tail(&h5->rel, skb);
+ break;
+
+ case HCI_SCODATA_PKT:
+ skb_queue_tail(&h5->unrel, skb);
+ break;
+
+ default:
+ BT_ERR("Unknown packet type %u", bt_cb(skb)->pkt_type);
+ kfree_skb(skb);
+ break;
+ }
+
+ return 0;
+}
+
+static void h5_slip_delim(struct sk_buff *skb)
+{
+ const char delim = SLIP_DELIMITER;
+
+ memcpy(skb_put(skb, 1), &delim, 1);
+}
+
+static void h5_slip_one_byte(struct sk_buff *skb, u8 c)
+{
+ const char esc_delim[2] = { SLIP_ESC, SLIP_ESC_DELIM };
+ const char esc_esc[2] = { SLIP_ESC, SLIP_ESC_ESC };
+
+ switch (c) {
+ case SLIP_DELIMITER:
+ memcpy(skb_put(skb, 2), &esc_delim, 2);
+ break;
+ case SLIP_ESC:
+ memcpy(skb_put(skb, 2), &esc_esc, 2);
+ break;
+ default:
+ memcpy(skb_put(skb, 1), &c, 1);
+ }
+}
+
+static bool valid_packet_type(u8 type)
+{
+ switch (type) {
+ case HCI_ACLDATA_PKT:
+ case HCI_COMMAND_PKT:
+ case HCI_SCODATA_PKT:
+ case HCI_3WIRE_LINK_PKT:
+ case HCI_3WIRE_ACK_PKT:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static struct sk_buff *h5_prepare_pkt(struct hci_uart *hu, u8 pkt_type,
+ const u8 *data, size_t len)
+{
+ struct h5 *h5 = hu->priv;
+ struct sk_buff *nskb;
+ u8 hdr[4];
+ int i;
+
+ if (!valid_packet_type(pkt_type)) {
+ BT_ERR("Unknown packet type %u", pkt_type);
+ return NULL;
+ }
+
+ /*
+ * Max len of packet: (original len + 4 (H5 hdr) + 2 (crc)) * 2
+ * (because bytes 0xc0 and 0xdb are escaped, worst case is when
+ * the packet is all made of 0xc0 and 0xdb) + 2 (0xc0
+ * delimiters at start and end).
+ */
+ nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
+ if (!nskb)
+ return NULL;
+
+ bt_cb(nskb)->pkt_type = pkt_type;
+
+ h5_slip_delim(nskb);
+
+ hdr[0] = h5->tx_ack << 3;
+ clear_bit(H5_TX_ACK_REQ, &h5->flags);
+
+ /* Reliable packet? */
+ if (pkt_type == HCI_ACLDATA_PKT || pkt_type == HCI_COMMAND_PKT) {
+ hdr[0] |= 1 << 7;
+ hdr[0] |= h5->tx_seq;
+ h5->tx_seq = (h5->tx_seq + 1) % 8;
+ }
+
+ hdr[1] = pkt_type | ((len & 0x0f) << 4);
+ hdr[2] = len >> 4;
+ hdr[3] = ~((hdr[0] + hdr[1] + hdr[2]) & 0xff);
+
+ BT_DBG("%s tx: seq %u ack %u crc %u rel %u type %u len %u",
+ hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
+ H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
+ H5_HDR_LEN(hdr));
+
+ for (i = 0; i < 4; i++)
+ h5_slip_one_byte(nskb, hdr[i]);
+
+ for (i = 0; i < len; i++)
+ h5_slip_one_byte(nskb, data[i]);
+
+ h5_slip_delim(nskb);
+
+ return nskb;
+}
+
+static struct sk_buff *h5_dequeue(struct hci_uart *hu)
+{
+ struct h5 *h5 = hu->priv;
+ unsigned long flags;
+ struct sk_buff *skb, *nskb;
+
+ if (h5->sleep != H5_AWAKE) {
+ const unsigned char wakeup_req[] = { 0x05, 0xfa };
+
+ if (h5->sleep == H5_WAKING_UP)
+ return NULL;
+
+ h5->sleep = H5_WAKING_UP;
+ BT_DBG("Sending wakeup request");
+
+ mod_timer(&h5->timer, jiffies + HZ / 100);
+ return h5_prepare_pkt(hu, HCI_3WIRE_LINK_PKT, wakeup_req, 2);
+ }
+
+ if ((skb = skb_dequeue(&h5->unrel)) != NULL) {
+ nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
+ skb->data, skb->len);
+ if (nskb) {
+ kfree_skb(skb);
+ return nskb;
+ }
+
+ skb_queue_head(&h5->unrel, skb);
+ BT_ERR("Could not dequeue pkt because alloc_skb failed");
+ }
+
+ spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
+
+ if (h5->unack.qlen >= h5->tx_win)
+ goto unlock;
+
+ if ((skb = skb_dequeue(&h5->rel)) != NULL) {
+ nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
+ skb->data, skb->len);
+ if (nskb) {
+ __skb_queue_tail(&h5->unack, skb);
+ mod_timer(&h5->timer, jiffies + H5_ACK_TIMEOUT);
+ spin_unlock_irqrestore(&h5->unack.lock, flags);
+ return nskb;
+ }
+
+ skb_queue_head(&h5->rel, skb);
+ BT_ERR("Could not dequeue pkt because alloc_skb failed");
+ }
+
+unlock:
+ spin_unlock_irqrestore(&h5->unack.lock, flags);
+
+ if (test_bit(H5_TX_ACK_REQ, &h5->flags))
+ return h5_prepare_pkt(hu, HCI_3WIRE_ACK_PKT, NULL, 0);
+
+ return NULL;
+}
+
+static int h5_flush(struct hci_uart *hu)
+{
+ BT_DBG("hu %p", hu);
+ return 0;
+}
+
+static struct hci_uart_proto h5p = {
+ .id = HCI_UART_3WIRE,
+ .open = h5_open,
+ .close = h5_close,
+ .recv = h5_recv,
+ .enqueue = h5_enqueue,
+ .dequeue = h5_dequeue,
+ .flush = h5_flush,
+};
+
+int __init h5_init(void)
+{
+ int err = hci_uart_register_proto(&h5p);
+
+ if (!err)
+ BT_INFO("HCI Three-wire UART (H5) protocol initialized");
+ else
+ BT_ERR("HCI Three-wire UART (H5) protocol init failed");
+
+ return err;
+}
+
+int __exit h5_deinit(void)
+{
+ return hci_uart_unregister_proto(&h5p);
+}