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/*
*
* 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 H5_TXWINSIZE 4
#define H5_ACK_TIMEOUT msecs_to_jiffies(250)
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 */
struct sk_buff *rx_skb;
struct timer_list timer; /* Retransmission timer */
bool txack_req;
u8 msgq_txseq;
};
static void h5_timed_event(unsigned long arg)
{
struct hci_uart *hu = (struct hci_uart *) arg;
struct h5 *h5 = hu->priv;
struct sk_buff *skb;
unsigned long flags;
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->msgq_txseq = (h5->msgq_txseq - 1) & 0x07;
skb_queue_head(&h5->rel, skb);
}
spin_unlock_irqrestore(&h5->unack.lock, flags);
hci_uart_tx_wakeup(hu);
}
static int h5_open(struct hci_uart *hu)
{
struct h5 *h5;
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);
init_timer(&h5->timer);
h5->timer.function = h5_timed_event;
h5->timer.data = (unsigned long) hu;
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 int h5_recv(struct hci_uart *hu, void *data, int count)
{
return -ENOSYS;
}
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;
}
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 struct sk_buff *h5_prepare_pkt(struct h5 *h5, struct sk_buff *skb)
{
h5->txack_req = false;
return NULL;
}
static struct sk_buff *h5_prepare_ack(struct h5 *h5)
{
h5->txack_req = false;
return NULL;
}
static struct sk_buff *h5_dequeue(struct hci_uart *hu)
{
struct h5 *h5 = hu->priv;
unsigned long flags;
struct sk_buff *skb, *nskb;
if ((skb = skb_dequeue(&h5->unrel)) != NULL) {
nskb = h5_prepare_pkt(h5, skb);
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_TXWINSIZE)
goto unlock;
if ((skb = skb_dequeue(&h5->rel)) != NULL) {
nskb = h5_prepare_pkt(h5, skb);
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 (h5->txack_req)
return h5_prepare_ack(h5);
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);
}
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