[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 <ohad@bencohen.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 531 insertions, 0 deletions

diff --git a/drivers/bluetooth/hci_ll.c b/drivers/bluetooth/hci_ll.c
new file mode 100644
index 000000000000..8c3e62a17b4a
--- /dev/null
+++ b/drivers/bluetooth/hci_ll.c
@@ -0,0 +1,531 @@
+/*
+ *  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;
+} __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);
+}