/*
* Texas Instruments' Bluetooth HCILL UART protocol
*
* HCILL (HCI Low Level) is a Texas Instruments' power management
* protocol extension to H4.
*
* Copyright (C) 2007 Texas Instruments, Inc.
*
* Written by Ohad Ben-Cohen <ohad@bencohen.org>
*
* Acknowledgements:
* This file is based on hci_h4.c, which was written
* by Maxim Krasnyansky and Marcel Holtmann.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation
*
* 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/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/signal.h>
#include <linux/ioctl.h>
#include <linux/skbuff.h>
#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include "hci_uart.h"
/* HCILL commands */
#define HCILL_GO_TO_SLEEP_IND 0x30
#define HCILL_GO_TO_SLEEP_ACK 0x31
#define HCILL_WAKE_UP_IND 0x32
#define HCILL_WAKE_UP_ACK 0x33
/* HCILL receiver States */
#define HCILL_W4_PACKET_TYPE 0
#define HCILL_W4_EVENT_HDR 1
#define HCILL_W4_ACL_HDR 2
#define HCILL_W4_SCO_HDR 3
#define HCILL_W4_DATA 4
/* HCILL states */
enum hcill_states_e {
HCILL_ASLEEP,
HCILL_ASLEEP_TO_AWAKE,
HCILL_AWAKE,
HCILL_AWAKE_TO_ASLEEP
};
struct hcill_cmd {
u8 cmd;
} __packed;
struct ll_struct {
unsigned long rx_state;
unsigned long rx_count;
struct sk_buff *rx_skb;
struct sk_buff_head txq;
spinlock_t hcill_lock; /* HCILL state lock */
unsigned long hcill_state; /* HCILL power state */
struct sk_buff_head tx_wait_q; /* HCILL wait queue */
};
/*
* Builds and sends an HCILL command packet.
* These are very simple packets with only 1 cmd byte
*/
static int send_hcill_cmd(u8 cmd, struct hci_uart *hu)
{
int err = 0;
struct sk_buff *skb = NULL;
struct ll_struct *ll = hu->priv;
struct hcill_cmd *hcill_packet;
BT_DBG("hu %p cmd 0x%x", hu, cmd);
/* allocate packet */
skb = bt_skb_alloc(1, GFP_ATOMIC);
if (!skb) {
BT_ERR("cannot allocate memory for HCILL packet");
err = -ENOMEM;
goto out;
}
/* prepare packet */
hcill_packet = (struct hcill_cmd *) skb_put(skb, 1);
hcill_packet->cmd = cmd;
/* send packet */
skb_queue_tail(&ll->txq, skb);
out:
return err;
}
/* Initialize protocol */
static int ll_open(struct hci_uart *hu)
{
struct ll_struct *ll;
BT_DBG("hu %p", hu);
ll = kzalloc(sizeof(*ll), GFP_KERNEL);
if (!ll)
return -ENOMEM;
skb_queue_head_init(&ll->txq);
skb_queue_head_init(&ll->tx_wait_q);
spin_lock_init(&ll->hcill_lock);
ll->hcill_state = HCILL_AWAKE;
hu->priv = ll;
return 0;
}
/* Flush protocol data */
static int ll_flush(struct hci_uart *hu)
{
struct ll_struct *ll = hu->priv;
BT_DBG("hu %p", hu);
skb_queue_purge(&ll->tx_wait_q);
skb_queue_purge(&ll->txq);
return 0;
}
/* Close protocol */
static int ll_close(struct hci_uart *hu)
{
struct ll_struct *ll = hu->priv;
BT_DBG("hu %p", hu);
skb_queue_purge(&ll->tx_wait_q);
skb_queue_purge(&ll->txq);
kfree_skb(ll->rx_skb);
hu->priv = NULL;
kfree(ll);
return 0;
}
/*
* internal function, which does common work of the device wake up process:
* 1. places all pending packets (waiting in tx_wait_q list) in txq list.
* 2. changes internal state to HCILL_AWAKE.
* Note: assumes that hcill_lock spinlock is taken,
* shouldn't be called otherwise!
*/
static void __ll_do_awake(struct ll_struct *ll)
{
struct sk_buff *skb = NULL;
while ((skb = skb_dequeue(&ll->tx_wait_q)))
skb_queue_tail(&ll->txq, skb);
ll->hcill_state = HCILL_AWAKE;
}
/*
* Called upon a wake-up-indication from the device
*/
static void ll_device_want_to_wakeup(struct hci_uart *hu)
{
unsigned long flags;
struct ll_struct *ll = hu->priv;
BT_DBG("hu %p", hu);
/* lock hcill state */
spin_lock_irqsave(&ll->hcill_lock, flags);
switch (ll->hcill_state) {
case HCILL_ASLEEP_TO_AWAKE:
/*
* This state means that both the host and the BRF chip
* have simultaneously sent a wake-up-indication packet.
* Traditionally, in this case, receiving a wake-up-indication
* was enough and an additional wake-up-ack wasn't needed.
* This has changed with the BRF6350, which does require an
* explicit wake-up-ack. Other BRF versions, which do not
* require an explicit ack here, do accept it, thus it is
* perfectly safe to always send one.
*/
BT_DBG("dual wake-up-indication");
/* deliberate fall-through - do not add break */
case HCILL_ASLEEP:
/* acknowledge device wake up */
if (send_hcill_cmd(HCILL_WAKE_UP_ACK, hu) < 0) {
BT_ERR("cannot acknowledge device wake up");
goto out;
}
break;
default:
/* any other state is illegal */
BT_ERR("received HCILL_WAKE_UP_IND in state %ld", ll->hcill_state);
break;
}
/* send pending packets and change state to HCILL_AWAKE */
__ll_do_awake(ll);
out:
spin_unlock_irqrestore(&ll->hcill_lock, flags);
/* actually send the packets */
hci_uart_tx_wakeup(hu);
}
/*
* Called upon a sleep-indication from the device
*/
static void ll_device_want_to_sleep(struct hci_uart *hu)
{
unsigned long flags;
struct ll_struct *ll = hu->priv;
BT_DBG("hu %p", hu);
/* lock hcill state */
spin_lock_irqsave(&ll->hcill_lock, flags);
/* sanity check */
if (ll->hcill_state != HCILL_AWAKE)
BT_ERR("ERR: HCILL_GO_TO_SLEEP_IND in state %ld", ll->hcill_state);
/* acknowledge device sleep */
if (send_hcill_cmd(HCILL_GO_TO_SLEEP_ACK, hu) < 0) {
BT_ERR("cannot acknowledge device sleep");
goto out;
}
/* update state */
ll->hcill_state = HCILL_ASLEEP;
out:
spin_unlock_irqrestore(&ll->hcill_lock, flags);
/* actually send the sleep ack packet */
hci_uart_tx_wakeup(hu);
}
/*
* Called upon wake-up-acknowledgement from the device
*/
static void ll_device_woke_up(struct hci_uart *hu)
{
unsigned long flags;
struct ll_struct *ll = hu->priv;
BT_DBG("hu %p", hu);
/* lock hcill state */
spin_lock_irqsave(&ll->hcill_lock, flags);
/* sanity check */
if (ll->hcill_state != HCILL_ASLEEP_TO_AWAKE)
BT_ERR("received HCILL_WAKE_UP_ACK in state %ld", ll->hcill_state);
/* send pending packets and change state to HCILL_AWAKE */
__ll_do_awake(ll);
spin_unlock_irqrestore(&ll->hcill_lock, flags);
/* actually send the packets */
hci_uart_tx_wakeup(hu);
}
/* Enqueue frame for transmittion (padding, crc, etc) */
/* may be called from two simultaneous tasklets */
static int ll_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
unsigned long flags = 0;
struct ll_struct *ll = hu->priv;
BT_DBG("hu %p skb %p", hu, skb);
/* Prepend skb with frame type */
memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
/* lock hcill state */
spin_lock_irqsave(&ll->hcill_lock, flags);
/* act according to current state */
switch (ll->hcill_state) {
case HCILL_AWAKE:
BT_DBG("device awake, sending normally");
skb_queue_tail(&ll->txq, skb);
break;
case HCILL_ASLEEP:
BT_DBG("device asleep, waking up and queueing packet");
/* save packet for later */
skb_queue_tail(&ll->tx_wait_q, skb);
/* awake device */
if (send_hcill_cmd(HCILL_WAKE_UP_IND, hu) < 0) {
BT_ERR("cannot wake up device");
break;
}
ll->hcill_state = HCILL_ASLEEP_TO_AWAKE;
break;
case HCILL_ASLEEP_TO_AWAKE:
BT_DBG("device waking up, queueing packet");
/* transient state; just keep packet for later */
skb_queue_tail(&ll->tx_wait_q, skb);
break;
default:
BT_ERR("illegal hcill state: %ld (losing packet)", ll->hcill_state);
kfree_skb(skb);
break;
}
spin_unlock_irqrestore(&ll->hcill_lock, flags);
return 0;
}
static inline int ll_check_data_len(struct hci_dev *hdev, struct ll_struct *ll, int len)
{
int room = skb_tailroom(ll->rx_skb);
BT_DBG("len %d room %d", len, room);
if (!len) {
hci_recv_frame(hdev, ll->rx_skb);
} else if (len > room) {
BT_ERR("Data length is too large");
kfree_skb(ll->rx_skb);
} else {
ll->rx_state = HCILL_W4_DATA;
ll->rx_count = len;
return len;
}
ll->rx_state = HCILL_W4_PACKET_TYPE;
ll->rx_skb = NULL;
ll->rx_count = 0;
return 0;
}
/* Recv data */
static int ll_recv(struct hci_uart *hu, const void *data, int count)
{
struct ll_struct *ll = hu->priv;
const char *ptr;
struct hci_event_hdr *eh;
struct hci_acl_hdr *ah;
struct hci_sco_hdr *sh;
int len, type, dlen;
BT_DBG("hu %p count %d rx_state %ld rx_count %ld", hu, count, ll->rx_state, ll->rx_count);
ptr = data;
while (count) {
if (ll->rx_count) {
len = min_t(unsigned int, ll->rx_count, count);
memcpy(skb_put(ll->rx_skb, len), ptr, len);
ll->rx_count -= len; count -= len; ptr += len;
if (ll->rx_count)
continue;
switch (ll->rx_state) {
case HCILL_W4_DATA:
BT_DBG("Complete data");
hci_recv_frame(hu->hdev, ll->rx_skb);
ll->rx_state = HCILL_W4_PACKET_TYPE;
ll->rx_skb = NULL;
continue;
case HCILL_W4_EVENT_HDR:
eh = hci_event_hdr(ll->rx_skb);
BT_DBG("Event header: evt 0x%2.2x plen %d", eh->evt, eh->plen);
ll_check_data_len(hu->hdev, ll, eh->plen);
continue;
case HCILL_W4_ACL_HDR:
ah = hci_acl_hdr(ll->rx_skb);
dlen = __le16_to_cpu(ah->dlen);
BT_DBG("ACL header: dlen %d", dlen);
ll_check_data_len(hu->hdev, ll, dlen);
continue;
case HCILL_W4_SCO_HDR:
sh = hci_sco_hdr(ll->rx_skb);
BT_DBG("SCO header: dlen %d", sh->dlen);
ll_check_data_len(hu->hdev, ll, sh->dlen);
continue;
}
}
/* HCILL_W4_PACKET_TYPE */
switch (*ptr) {
case HCI_EVENT_PKT:
BT_DBG("Event packet");
ll->rx_state = HCILL_W4_EVENT_HDR;
ll->rx_count = HCI_EVENT_HDR_SIZE;
type = HCI_EVENT_PKT;
break;
case HCI_ACLDATA_PKT:
BT_DBG("ACL packet");
ll->rx_state = HCILL_W4_ACL_HDR;
ll->rx_count = HCI_ACL_HDR_SIZE;
type = HCI_ACLDATA_PKT;
break;
case HCI_SCODATA_PKT:
BT_DBG("SCO packet");
ll->rx_state = HCILL_W4_SCO_HDR;
ll->rx_count = HCI_SCO_HDR_SIZE;
type = HCI_SCODATA_PKT;
break;
/* HCILL signals */
case HCILL_GO_TO_SLEEP_IND:
BT_DBG("HCILL_GO_TO_SLEEP_IND packet");
ll_device_want_to_sleep(hu);
ptr++; count--;
continue;
case HCILL_GO_TO_SLEEP_ACK:
/* shouldn't happen */
BT_ERR("received HCILL_GO_TO_SLEEP_ACK (in state %ld)", ll->hcill_state);
ptr++; count--;
continue;
case HCILL_WAKE_UP_IND:
BT_DBG("HCILL_WAKE_UP_IND packet");
ll_device_want_to_wakeup(hu);
ptr++; count--;
continue;
case HCILL_WAKE_UP_ACK:
BT_DBG("HCILL_WAKE_UP_ACK packet");
ll_device_woke_up(hu);
ptr++; count--;
continue;
default:
BT_ERR("Unknown HCI packet type %2.2x", (__u8)*ptr);
hu->hdev->stat.err_rx++;
ptr++; count--;
continue;
}
ptr++; count--;
/* Allocate packet */
ll->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);
if (!ll->rx_skb) {
BT_ERR("Can't allocate mem for new packet");
ll->rx_state = HCILL_W4_PACKET_TYPE;
ll->rx_count = 0;
return -ENOMEM;
}
bt_cb(ll->rx_skb)->pkt_type = type;
}
return count;
}
static struct sk_buff *ll_dequeue(struct hci_uart *hu)
{
struct ll_struct *ll = hu->priv;
return skb_dequeue(&ll->txq);
}
static const struct hci_uart_proto llp = {
.id = HCI_UART_LL,
.name = "LL",
.open = ll_open,
.close = ll_close,
.recv = ll_recv,
.enqueue = ll_enqueue,
.dequeue = ll_dequeue,
.flush = ll_flush,
};
int __init ll_init(void)
{
return hci_uart_register_proto(&llp);
}
int __exit ll_deinit(void)
{
return hci_uart_unregister_proto(&llp);
}
