- 根目录:
- drivers
- bluetooth
- hci_h5.c
/*
*
* 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(hu->hdev, 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);
}