[Bluetooth] Add UART driver for Texas Instruments' BRF63xx chips

Add support for Texas Instruments' HCI Low Level (HCILL) Bluetooth
protocol, which is a power management extension to H4. The HCILL is
widely used by TI's BRF63xx Bluetooth chips.

Signed-off-by: Ohad Ben-Cohen <[e-mail]>
Signed-off-by: Marcel Holtmann <[e-mail]>

drivers/bluetooth/Kconfig

···
 
 	  Say Y here to compile support for HCI BCSP protocol.
 
+config BT_HCIUART_LL
+	bool "HCILL protocol support"
+	depends on BT_HCIUART
+	help
+	  HCILL (HCI Low Level) is a serial protocol for communication
+	  between Bluetooth device and host. This protocol is required for
+	  serial Bluetooth devices that are based on Texas Instruments'
+	  BRF chips.
+
+	  Say Y here to compile support for HCILL protocol.
+
 config BT_HCIBCM203X
 	tristate "HCI BCM203x USB driver"
 	depends on USB

drivers/bluetooth/Makefile

···
 hci_uart-y				:= hci_ldisc.o
 hci_uart-$(CONFIG_BT_HCIUART_H4)	+= hci_h4.o
 hci_uart-$(CONFIG_BT_HCIUART_BCSP)	+= hci_bcsp.o
+hci_uart-$(CONFIG_BT_HCIUART_LL)	+= hci_ll.o
 hci_uart-objs				:= $(hci_uart-y)

drivers/bluetooth/hci_ldisc.c

···
 #ifdef CONFIG_BT_HCIUART_BCSP
 	bcsp_init();
 #endif
-	
+#ifdef CONFIG_BT_HCIUART_LL
+	ll_init();
+#endif
+
 	return 0;
 }
 
···
 #endif
 #ifdef CONFIG_BT_HCIUART_BCSP
 	bcsp_deinit();
+#endif
+#ifdef CONFIG_BT_HCIUART_LL
+	ll_deinit();
 #endif
 
 	/* Release tty registration of line discipline */

drivers/bluetooth/hci_ll.c

···
+/*
+ *  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 <[e-mail]>
+ *
+ *  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;
+} __attribute__((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;
+	skb->dev = (void *) hu->hdev;
+
+	/* 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_ATOMIC);
+	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);
+
+	if (ll->rx_skb)
+		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:
+		/* acknowledge device wake up */
+		if (send_hcill_cmd(HCILL_WAKE_UP_ACK, hu) < 0) {
+			BT_ERR("cannot acknowledge device wake up");
+			goto out;
+		}
+		break;
+	case HCILL_ASLEEP_TO_AWAKE:
+		/*
+		 * this state means that a wake-up-indication
+		 * is already on its way to the device,
+		 * and will serve as the required wake-up-ack
+		 */
+		BT_DBG("dual wake-up-indication");
+		break;
+	default:
+		/* any other state are 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 ll_struct *ll, int len)
+{
+	register int room = skb_tailroom(ll->rx_skb);
+
+	BT_DBG("len %d room %d", len, room);
+
+	if (!len) {
+		hci_recv_frame(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, void *data, int count)
+{
+	struct ll_struct *ll = hu->priv;
+	register char *ptr;
+	struct hci_event_hdr *eh;
+	struct hci_acl_hdr   *ah;
+	struct hci_sco_hdr   *sh;
+	register 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(ll->rx_skb);
+
+				ll->rx_state = HCILL_W4_PACKET_TYPE;
+				ll->rx_skb = NULL;
+				continue;
+
+			case HCILL_W4_EVENT_HDR:
+				eh = (struct hci_event_hdr *) ll->rx_skb->data;
+
+				BT_DBG("Event header: evt 0x%2.2x plen %d", eh->evt, eh->plen);
+
+				ll_check_data_len(ll, eh->plen);
+				continue;
+
+			case HCILL_W4_ACL_HDR:
+				ah = (struct hci_acl_hdr *) ll->rx_skb->data;
+				dlen = __le16_to_cpu(ah->dlen);
+
+				BT_DBG("ACL header: dlen %d", dlen);
+
+				ll_check_data_len(ll, dlen);
+				continue;
+
+			case HCILL_W4_SCO_HDR:
+				sh = (struct hci_sco_hdr *) ll->rx_skb->data;
+
+				BT_DBG("SCO header: dlen %d", sh->dlen);
+
+				ll_check_data_len(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 0;
+		}
+
+		ll->rx_skb->dev = (void *) hu->hdev;
+		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 struct hci_uart_proto llp = {
+	.id		= HCI_UART_LL,
+	.open		= ll_open,
+	.close		= ll_close,
+	.recv		= ll_recv,
+	.enqueue	= ll_enqueue,
+	.dequeue	= ll_dequeue,
+	.flush		= ll_flush,
+};
+
+int ll_init(void)
+{
+	int err = hci_uart_register_proto(&llp);
+
+	if (!err)
+		BT_INFO("HCILL protocol initialized");
+	else
+		BT_ERR("HCILL protocol registration failed");
+
+	return err;
+}
+
+int ll_deinit(void)
+{
+	return hci_uart_unregister_proto(&llp);
+}

drivers/bluetooth/hci_uart.h

···
 #define HCIUARTGETDEVICE	_IOR('U', 202, int)
 
 /* UART protocols */
-#define HCI_UART_MAX_PROTO	4
+#define HCI_UART_MAX_PROTO	5
 
 #define HCI_UART_H4	0
 #define HCI_UART_BCSP	1
 #define HCI_UART_3WIRE	2
 #define HCI_UART_H4DS	3
+#define HCI_UART_LL	4
 
 struct hci_uart;
 
···
 #ifdef CONFIG_BT_HCIUART_BCSP
 int bcsp_init(void);
 int bcsp_deinit(void);
+#endif
+
+#ifdef CONFIG_BT_HCIUART_LL
+int ll_init(void);
+int ll_deinit(void);
 #endif