Linux 4.19-rc7

[linux-2.6/btrfs-unstable.git] / drivers / bluetooth / hci_qca.c

/*
 *  Bluetooth Software UART Qualcomm protocol
 *
 *  HCI_IBS (HCI In-Band Sleep) is Qualcomm's power management
 *  protocol extension to H4.
 *
 *  Copyright (C) 2007 Texas Instruments, Inc.
 *  Copyright (c) 2010, 2012, 2018 The Linux Foundation. All rights reserved.
 *
 *  Acknowledgements:
 *  This file is based on hci_ll.c, which was...
 *  Written by Ohad Ben-Cohen <ohad@bencohen.org>
 *  which was in turn 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/kernel.h>
#include <linux/clk.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/gpio/consumer.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/serdev.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>

#include "hci_uart.h"
#include "btqca.h"

/* HCI_IBS protocol messages */
#define HCI_IBS_SLEEP_IND       0xFE
#define HCI_IBS_WAKE_IND        0xFD
#define HCI_IBS_WAKE_ACK        0xFC
#define HCI_MAX_IBS_SIZE        10

/* Controller states */
#define STATE_IN_BAND_SLEEP_ENABLED     1

#define IBS_WAKE_RETRANS_TIMEOUT_MS     100
#define IBS_TX_IDLE_TIMEOUT_MS          2000
#define BAUDRATE_SETTLE_TIMEOUT_MS      300

/* susclk rate */
#define SUSCLK_RATE_32KHZ       32768

/* HCI_IBS transmit side sleep protocol states */
enum tx_ibs_states {
        HCI_IBS_TX_ASLEEP,
        HCI_IBS_TX_WAKING,
        HCI_IBS_TX_AWAKE,
};

/* HCI_IBS receive side sleep protocol states */
enum rx_states {
        HCI_IBS_RX_ASLEEP,
        HCI_IBS_RX_AWAKE,
};

/* HCI_IBS transmit and receive side clock state vote */
enum hci_ibs_clock_state_vote {
        HCI_IBS_VOTE_STATS_UPDATE,
        HCI_IBS_TX_VOTE_CLOCK_ON,
        HCI_IBS_TX_VOTE_CLOCK_OFF,
        HCI_IBS_RX_VOTE_CLOCK_ON,
        HCI_IBS_RX_VOTE_CLOCK_OFF,
};

struct qca_data {
        struct hci_uart *hu;
        struct sk_buff *rx_skb;
        struct sk_buff_head txq;
        struct sk_buff_head tx_wait_q;  /* HCI_IBS wait queue   */
        spinlock_t hci_ibs_lock;        /* HCI_IBS state lock   */
        u8 tx_ibs_state;        /* HCI_IBS transmit side power state*/
        u8 rx_ibs_state;        /* HCI_IBS receive side power state */
        bool tx_vote;           /* Clock must be on for TX */
        bool rx_vote;           /* Clock must be on for RX */
        struct timer_list tx_idle_timer;
        u32 tx_idle_delay;
        struct timer_list wake_retrans_timer;
        u32 wake_retrans;
        struct workqueue_struct *workqueue;
        struct work_struct ws_awake_rx;
        struct work_struct ws_awake_device;
        struct work_struct ws_rx_vote_off;
        struct work_struct ws_tx_vote_off;
        unsigned long flags;

        /* For debugging purpose */
        u64 ibs_sent_wacks;
        u64 ibs_sent_slps;
        u64 ibs_sent_wakes;
        u64 ibs_recv_wacks;
        u64 ibs_recv_slps;
        u64 ibs_recv_wakes;
        u64 vote_last_jif;
        u32 vote_on_ms;
        u32 vote_off_ms;
        u64 tx_votes_on;
        u64 rx_votes_on;
        u64 tx_votes_off;
        u64 rx_votes_off;
        u64 votes_on;
        u64 votes_off;
};

enum qca_speed_type {
        QCA_INIT_SPEED = 1,
        QCA_OPER_SPEED
};

/*
 * Voltage regulator information required for configuring the
 * QCA Bluetooth chipset
 */
struct qca_vreg {
        const char *name;
        unsigned int min_uV;
        unsigned int max_uV;
        unsigned int load_uA;
};

struct qca_vreg_data {
        enum qca_btsoc_type soc_type;
        struct qca_vreg *vregs;
        size_t num_vregs;
};

/*
 * Platform data for the QCA Bluetooth power driver.
 */
struct qca_power {
        struct device *dev;
        const struct qca_vreg_data *vreg_data;
        struct regulator_bulk_data *vreg_bulk;
        bool vregs_on;
};

struct qca_serdev {
        struct hci_uart  serdev_hu;
        struct gpio_desc *bt_en;
        struct clk       *susclk;
        enum qca_btsoc_type btsoc_type;
        struct qca_power *bt_power;
        u32 init_speed;
        u32 oper_speed;
};

static int qca_power_setup(struct hci_uart *hu, bool on);
static void qca_power_shutdown(struct hci_dev *hdev);

static void __serial_clock_on(struct tty_struct *tty)
{
        /* TODO: Some chipset requires to enable UART clock on client
         * side to save power consumption or manual work is required.
         * Please put your code to control UART clock here if needed
         */
}

static void __serial_clock_off(struct tty_struct *tty)
{
        /* TODO: Some chipset requires to disable UART clock on client
         * side to save power consumption or manual work is required.
         * Please put your code to control UART clock off here if needed
         */
}

/* serial_clock_vote needs to be called with the ibs lock held */
static void serial_clock_vote(unsigned long vote, struct hci_uart *hu)
{
        struct qca_data *qca = hu->priv;
        unsigned int diff;

        bool old_vote = (qca->tx_vote | qca->rx_vote);
        bool new_vote;

        switch (vote) {
        case HCI_IBS_VOTE_STATS_UPDATE:
                diff = jiffies_to_msecs(jiffies - qca->vote_last_jif);

                if (old_vote)
                        qca->vote_off_ms += diff;
                else
                        qca->vote_on_ms += diff;
                return;

        case HCI_IBS_TX_VOTE_CLOCK_ON:
                qca->tx_vote = true;
                qca->tx_votes_on++;
                new_vote = true;
                break;

        case HCI_IBS_RX_VOTE_CLOCK_ON:
                qca->rx_vote = true;
                qca->rx_votes_on++;
                new_vote = true;
                break;

        case HCI_IBS_TX_VOTE_CLOCK_OFF:
                qca->tx_vote = false;
                qca->tx_votes_off++;
                new_vote = qca->rx_vote | qca->tx_vote;
                break;

        case HCI_IBS_RX_VOTE_CLOCK_OFF:
                qca->rx_vote = false;
                qca->rx_votes_off++;
                new_vote = qca->rx_vote | qca->tx_vote;
                break;

        default:
                BT_ERR("Voting irregularity");
                return;
        }

        if (new_vote != old_vote) {
                if (new_vote)
                        __serial_clock_on(hu->tty);
                else
                        __serial_clock_off(hu->tty);

                BT_DBG("Vote serial clock %s(%s)", new_vote ? "true" : "false",
                       vote ? "true" : "false");

                diff = jiffies_to_msecs(jiffies - qca->vote_last_jif);

                if (new_vote) {
                        qca->votes_on++;
                        qca->vote_off_ms += diff;
                } else {
                        qca->votes_off++;
                        qca->vote_on_ms += diff;
                }
                qca->vote_last_jif = jiffies;
        }
}

/* Builds and sends an HCI_IBS command packet.
 * These are very simple packets with only 1 cmd byte.
 */
static int send_hci_ibs_cmd(u8 cmd, struct hci_uart *hu)
{
        int err = 0;
        struct sk_buff *skb = NULL;
        struct qca_data *qca = hu->priv;

        BT_DBG("hu %p send hci ibs cmd 0x%x", hu, cmd);

        skb = bt_skb_alloc(1, GFP_ATOMIC);
        if (!skb) {
                BT_ERR("Failed to allocate memory for HCI_IBS packet");
                return -ENOMEM;
        }

        /* Assign HCI_IBS type */
        skb_put_u8(skb, cmd);

        skb_queue_tail(&qca->txq, skb);

        return err;
}

static void qca_wq_awake_device(struct work_struct *work)
{
        struct qca_data *qca = container_of(work, struct qca_data,
                                            ws_awake_device);
        struct hci_uart *hu = qca->hu;
        unsigned long retrans_delay;

        BT_DBG("hu %p wq awake device", hu);

        /* Vote for serial clock */
        serial_clock_vote(HCI_IBS_TX_VOTE_CLOCK_ON, hu);

        spin_lock(&qca->hci_ibs_lock);

        /* Send wake indication to device */
        if (send_hci_ibs_cmd(HCI_IBS_WAKE_IND, hu) < 0)
                BT_ERR("Failed to send WAKE to device");

        qca->ibs_sent_wakes++;

        /* Start retransmit timer */
        retrans_delay = msecs_to_jiffies(qca->wake_retrans);
        mod_timer(&qca->wake_retrans_timer, jiffies + retrans_delay);

        spin_unlock(&qca->hci_ibs_lock);

        /* Actually send the packets */
        hci_uart_tx_wakeup(hu);
}

static void qca_wq_awake_rx(struct work_struct *work)
{
        struct qca_data *qca = container_of(work, struct qca_data,
                                            ws_awake_rx);
        struct hci_uart *hu = qca->hu;

        BT_DBG("hu %p wq awake rx", hu);

        serial_clock_vote(HCI_IBS_RX_VOTE_CLOCK_ON, hu);

        spin_lock(&qca->hci_ibs_lock);
        qca->rx_ibs_state = HCI_IBS_RX_AWAKE;

        /* Always acknowledge device wake up,
         * sending IBS message doesn't count as TX ON.
         */
        if (send_hci_ibs_cmd(HCI_IBS_WAKE_ACK, hu) < 0)
                BT_ERR("Failed to acknowledge device wake up");

        qca->ibs_sent_wacks++;

        spin_unlock(&qca->hci_ibs_lock);

        /* Actually send the packets */
        hci_uart_tx_wakeup(hu);
}

static void qca_wq_serial_rx_clock_vote_off(struct work_struct *work)
{
        struct qca_data *qca = container_of(work, struct qca_data,
                                            ws_rx_vote_off);
        struct hci_uart *hu = qca->hu;

        BT_DBG("hu %p rx clock vote off", hu);

        serial_clock_vote(HCI_IBS_RX_VOTE_CLOCK_OFF, hu);
}

static void qca_wq_serial_tx_clock_vote_off(struct work_struct *work)
{
        struct qca_data *qca = container_of(work, struct qca_data,
                                            ws_tx_vote_off);
        struct hci_uart *hu = qca->hu;

        BT_DBG("hu %p tx clock vote off", hu);

        /* Run HCI tx handling unlocked */
        hci_uart_tx_wakeup(hu);

        /* Now that message queued to tty driver, vote for tty clocks off.
         * It is up to the tty driver to pend the clocks off until tx done.
         */
        serial_clock_vote(HCI_IBS_TX_VOTE_CLOCK_OFF, hu);
}

static void hci_ibs_tx_idle_timeout(struct timer_list *t)
{
        struct qca_data *qca = from_timer(qca, t, tx_idle_timer);
        struct hci_uart *hu = qca->hu;
        unsigned long flags;

        BT_DBG("hu %p idle timeout in %d state", hu, qca->tx_ibs_state);

        spin_lock_irqsave_nested(&qca->hci_ibs_lock,
                                 flags, SINGLE_DEPTH_NESTING);

        switch (qca->tx_ibs_state) {
        case HCI_IBS_TX_AWAKE:
                /* TX_IDLE, go to SLEEP */
                if (send_hci_ibs_cmd(HCI_IBS_SLEEP_IND, hu) < 0) {
                        BT_ERR("Failed to send SLEEP to device");
                        break;
                }
                qca->tx_ibs_state = HCI_IBS_TX_ASLEEP;
                qca->ibs_sent_slps++;
                queue_work(qca->workqueue, &qca->ws_tx_vote_off);
                break;

        case HCI_IBS_TX_ASLEEP:
        case HCI_IBS_TX_WAKING:
                /* Fall through */

        default:
                BT_ERR("Spurious timeout tx state %d", qca->tx_ibs_state);
                break;
        }

        spin_unlock_irqrestore(&qca->hci_ibs_lock, flags);
}

static void hci_ibs_wake_retrans_timeout(struct timer_list *t)
{
        struct qca_data *qca = from_timer(qca, t, wake_retrans_timer);
        struct hci_uart *hu = qca->hu;
        unsigned long flags, retrans_delay;
        bool retransmit = false;

        BT_DBG("hu %p wake retransmit timeout in %d state",
                hu, qca->tx_ibs_state);

        spin_lock_irqsave_nested(&qca->hci_ibs_lock,
                                 flags, SINGLE_DEPTH_NESTING);

        switch (qca->tx_ibs_state) {
        case HCI_IBS_TX_WAKING:
                /* No WAKE_ACK, retransmit WAKE */
                retransmit = true;
                if (send_hci_ibs_cmd(HCI_IBS_WAKE_IND, hu) < 0) {
                        BT_ERR("Failed to acknowledge device wake up");
                        break;
                }
                qca->ibs_sent_wakes++;
                retrans_delay = msecs_to_jiffies(qca->wake_retrans);
                mod_timer(&qca->wake_retrans_timer, jiffies + retrans_delay);
                break;

        case HCI_IBS_TX_ASLEEP:
        case HCI_IBS_TX_AWAKE:
                /* Fall through */

        default:
                BT_ERR("Spurious timeout tx state %d", qca->tx_ibs_state);
                break;
        }

        spin_unlock_irqrestore(&qca->hci_ibs_lock, flags);

        if (retransmit)
                hci_uart_tx_wakeup(hu);
}

/* Initialize protocol */
static int qca_open(struct hci_uart *hu)
{
        struct qca_serdev *qcadev;
        struct qca_data *qca;
        int ret;

        BT_DBG("hu %p qca_open", hu);

        qca = kzalloc(sizeof(struct qca_data), GFP_KERNEL);
        if (!qca)
                return -ENOMEM;

        skb_queue_head_init(&qca->txq);
        skb_queue_head_init(&qca->tx_wait_q);
        spin_lock_init(&qca->hci_ibs_lock);
        qca->workqueue = alloc_ordered_workqueue("qca_wq", 0);
        if (!qca->workqueue) {
                BT_ERR("QCA Workqueue not initialized properly");
                kfree(qca);
                return -ENOMEM;
        }

        INIT_WORK(&qca->ws_awake_rx, qca_wq_awake_rx);
        INIT_WORK(&qca->ws_awake_device, qca_wq_awake_device);
        INIT_WORK(&qca->ws_rx_vote_off, qca_wq_serial_rx_clock_vote_off);
        INIT_WORK(&qca->ws_tx_vote_off, qca_wq_serial_tx_clock_vote_off);

        qca->hu = hu;

        /* Assume we start with both sides asleep -- extra wakes OK */
        qca->tx_ibs_state = HCI_IBS_TX_ASLEEP;
        qca->rx_ibs_state = HCI_IBS_RX_ASLEEP;

        /* clocks actually on, but we start votes off */
        qca->tx_vote = false;
        qca->rx_vote = false;
        qca->flags = 0;

        qca->ibs_sent_wacks = 0;
        qca->ibs_sent_slps = 0;
        qca->ibs_sent_wakes = 0;
        qca->ibs_recv_wacks = 0;
        qca->ibs_recv_slps = 0;
        qca->ibs_recv_wakes = 0;
        qca->vote_last_jif = jiffies;
        qca->vote_on_ms = 0;
        qca->vote_off_ms = 0;
        qca->votes_on = 0;
        qca->votes_off = 0;
        qca->tx_votes_on = 0;
        qca->tx_votes_off = 0;
        qca->rx_votes_on = 0;
        qca->rx_votes_off = 0;

        hu->priv = qca;

        if (hu->serdev) {
                serdev_device_open(hu->serdev);

                qcadev = serdev_device_get_drvdata(hu->serdev);
                if (qcadev->btsoc_type != QCA_WCN3990) {
                        gpiod_set_value_cansleep(qcadev->bt_en, 1);
                } else {
                        hu->init_speed = qcadev->init_speed;
                        hu->oper_speed = qcadev->oper_speed;
                        ret = qca_power_setup(hu, true);
                        if (ret) {
                                destroy_workqueue(qca->workqueue);
                                kfree_skb(qca->rx_skb);
                                hu->priv = NULL;
                                kfree(qca);
                                return ret;
                        }
                }
        }

        timer_setup(&qca->wake_retrans_timer, hci_ibs_wake_retrans_timeout, 0);
        qca->wake_retrans = IBS_WAKE_RETRANS_TIMEOUT_MS;

        timer_setup(&qca->tx_idle_timer, hci_ibs_tx_idle_timeout, 0);
        qca->tx_idle_delay = IBS_TX_IDLE_TIMEOUT_MS;

        BT_DBG("HCI_UART_QCA open, tx_idle_delay=%u, wake_retrans=%u",
               qca->tx_idle_delay, qca->wake_retrans);

        return 0;
}

static void qca_debugfs_init(struct hci_dev *hdev)
{
        struct hci_uart *hu = hci_get_drvdata(hdev);
        struct qca_data *qca = hu->priv;
        struct dentry *ibs_dir;
        umode_t mode;

        if (!hdev->debugfs)
                return;

        ibs_dir = debugfs_create_dir("ibs", hdev->debugfs);

        /* read only */
        mode = S_IRUGO;
        debugfs_create_u8("tx_ibs_state", mode, ibs_dir, &qca->tx_ibs_state);
        debugfs_create_u8("rx_ibs_state", mode, ibs_dir, &qca->rx_ibs_state);
        debugfs_create_u64("ibs_sent_sleeps", mode, ibs_dir,
                           &qca->ibs_sent_slps);
        debugfs_create_u64("ibs_sent_wakes", mode, ibs_dir,
                           &qca->ibs_sent_wakes);
        debugfs_create_u64("ibs_sent_wake_acks", mode, ibs_dir,
                           &qca->ibs_sent_wacks);
        debugfs_create_u64("ibs_recv_sleeps", mode, ibs_dir,
                           &qca->ibs_recv_slps);
        debugfs_create_u64("ibs_recv_wakes", mode, ibs_dir,
                           &qca->ibs_recv_wakes);
        debugfs_create_u64("ibs_recv_wake_acks", mode, ibs_dir,
                           &qca->ibs_recv_wacks);
        debugfs_create_bool("tx_vote", mode, ibs_dir, &qca->tx_vote);
        debugfs_create_u64("tx_votes_on", mode, ibs_dir, &qca->tx_votes_on);
        debugfs_create_u64("tx_votes_off", mode, ibs_dir, &qca->tx_votes_off);
        debugfs_create_bool("rx_vote", mode, ibs_dir, &qca->rx_vote);
        debugfs_create_u64("rx_votes_on", mode, ibs_dir, &qca->rx_votes_on);
        debugfs_create_u64("rx_votes_off", mode, ibs_dir, &qca->rx_votes_off);
        debugfs_create_u64("votes_on", mode, ibs_dir, &qca->votes_on);
        debugfs_create_u64("votes_off", mode, ibs_dir, &qca->votes_off);
        debugfs_create_u32("vote_on_ms", mode, ibs_dir, &qca->vote_on_ms);
        debugfs_create_u32("vote_off_ms", mode, ibs_dir, &qca->vote_off_ms);

        /* read/write */
        mode = S_IRUGO | S_IWUSR;
        debugfs_create_u32("wake_retrans", mode, ibs_dir, &qca->wake_retrans);
        debugfs_create_u32("tx_idle_delay", mode, ibs_dir,
                           &qca->tx_idle_delay);
}

/* Flush protocol data */
static int qca_flush(struct hci_uart *hu)
{
        struct qca_data *qca = hu->priv;

        BT_DBG("hu %p qca flush", hu);

        skb_queue_purge(&qca->tx_wait_q);
        skb_queue_purge(&qca->txq);

        return 0;
}

/* Close protocol */
static int qca_close(struct hci_uart *hu)
{
        struct qca_serdev *qcadev;
        struct qca_data *qca = hu->priv;

        BT_DBG("hu %p qca close", hu);

        serial_clock_vote(HCI_IBS_VOTE_STATS_UPDATE, hu);

        skb_queue_purge(&qca->tx_wait_q);
        skb_queue_purge(&qca->txq);
        del_timer(&qca->tx_idle_timer);
        del_timer(&qca->wake_retrans_timer);
        destroy_workqueue(qca->workqueue);
        qca->hu = NULL;

        if (hu->serdev) {
                qcadev = serdev_device_get_drvdata(hu->serdev);
                if (qcadev->btsoc_type == QCA_WCN3990)
                        qca_power_shutdown(hu->hdev);
                else
                        gpiod_set_value_cansleep(qcadev->bt_en, 0);

                serdev_device_close(hu->serdev);
        }

        kfree_skb(qca->rx_skb);

        hu->priv = NULL;

        kfree(qca);

        return 0;
}

/* Called upon a wake-up-indication from the device.
 */
static void device_want_to_wakeup(struct hci_uart *hu)
{
        unsigned long flags;
        struct qca_data *qca = hu->priv;

        BT_DBG("hu %p want to wake up", hu);

        spin_lock_irqsave(&qca->hci_ibs_lock, flags);

        qca->ibs_recv_wakes++;

        switch (qca->rx_ibs_state) {
        case HCI_IBS_RX_ASLEEP:
                /* Make sure clock is on - we may have turned clock off since
                 * receiving the wake up indicator awake rx clock.
                 */
                queue_work(qca->workqueue, &qca->ws_awake_rx);
                spin_unlock_irqrestore(&qca->hci_ibs_lock, flags);
                return;

        case HCI_IBS_RX_AWAKE:
                /* Always acknowledge device wake up,
                 * sending IBS message doesn't count as TX ON.
                 */
                if (send_hci_ibs_cmd(HCI_IBS_WAKE_ACK, hu) < 0) {
                        BT_ERR("Failed to acknowledge device wake up");
                        break;
                }
                qca->ibs_sent_wacks++;
                break;

        default:
                /* Any other state is illegal */
                BT_ERR("Received HCI_IBS_WAKE_IND in rx state %d",
                       qca->rx_ibs_state);
                break;
        }

        spin_unlock_irqrestore(&qca->hci_ibs_lock, flags);

        /* Actually send the packets */
        hci_uart_tx_wakeup(hu);
}

/* Called upon a sleep-indication from the device.
 */
static void device_want_to_sleep(struct hci_uart *hu)
{
        unsigned long flags;
        struct qca_data *qca = hu->priv;

        BT_DBG("hu %p want to sleep", hu);

        spin_lock_irqsave(&qca->hci_ibs_lock, flags);

        qca->ibs_recv_slps++;

        switch (qca->rx_ibs_state) {
        case HCI_IBS_RX_AWAKE:
                /* Update state */
                qca->rx_ibs_state = HCI_IBS_RX_ASLEEP;
                /* Vote off rx clock under workqueue */
                queue_work(qca->workqueue, &qca->ws_rx_vote_off);
                break;

        case HCI_IBS_RX_ASLEEP:
                /* Fall through */

        default:
                /* Any other state is illegal */
                BT_ERR("Received HCI_IBS_SLEEP_IND in rx state %d",
                       qca->rx_ibs_state);
                break;
        }

        spin_unlock_irqrestore(&qca->hci_ibs_lock, flags);
}

/* Called upon wake-up-acknowledgement from the device
 */
static void device_woke_up(struct hci_uart *hu)
{
        unsigned long flags, idle_delay;
        struct qca_data *qca = hu->priv;
        struct sk_buff *skb = NULL;

        BT_DBG("hu %p woke up", hu);

        spin_lock_irqsave(&qca->hci_ibs_lock, flags);

        qca->ibs_recv_wacks++;

        switch (qca->tx_ibs_state) {
        case HCI_IBS_TX_AWAKE:
                /* Expect one if we send 2 WAKEs */
                BT_DBG("Received HCI_IBS_WAKE_ACK in tx state %d",
                       qca->tx_ibs_state);
                break;

        case HCI_IBS_TX_WAKING:
                /* Send pending packets */
                while ((skb = skb_dequeue(&qca->tx_wait_q)))
                        skb_queue_tail(&qca->txq, skb);

                /* Switch timers and change state to HCI_IBS_TX_AWAKE */
                del_timer(&qca->wake_retrans_timer);
                idle_delay = msecs_to_jiffies(qca->tx_idle_delay);
                mod_timer(&qca->tx_idle_timer, jiffies + idle_delay);
                qca->tx_ibs_state = HCI_IBS_TX_AWAKE;
                break;

        case HCI_IBS_TX_ASLEEP:
                /* Fall through */

        default:
                BT_ERR("Received HCI_IBS_WAKE_ACK in tx state %d",
                       qca->tx_ibs_state);
                break;
        }

        spin_unlock_irqrestore(&qca->hci_ibs_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 qca_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
        unsigned long flags = 0, idle_delay;
        struct qca_data *qca = hu->priv;

        BT_DBG("hu %p qca enq skb %p tx_ibs_state %d", hu, skb,
               qca->tx_ibs_state);

        /* Prepend skb with frame type */
        memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);

        /* Don't go to sleep in middle of patch download or
         * Out-Of-Band(GPIOs control) sleep is selected.
         */
        if (!test_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags)) {
                skb_queue_tail(&qca->txq, skb);
                return 0;
        }

        spin_lock_irqsave(&qca->hci_ibs_lock, flags);

        /* Act according to current state */
        switch (qca->tx_ibs_state) {
        case HCI_IBS_TX_AWAKE:
                BT_DBG("Device awake, sending normally");
                skb_queue_tail(&qca->txq, skb);
                idle_delay = msecs_to_jiffies(qca->tx_idle_delay);
                mod_timer(&qca->tx_idle_timer, jiffies + idle_delay);
                break;

        case HCI_IBS_TX_ASLEEP:
                BT_DBG("Device asleep, waking up and queueing packet");
                /* Save packet for later */
                skb_queue_tail(&qca->tx_wait_q, skb);

                qca->tx_ibs_state = HCI_IBS_TX_WAKING;
                /* Schedule a work queue to wake up device */
                queue_work(qca->workqueue, &qca->ws_awake_device);
                break;

        case HCI_IBS_TX_WAKING:
                BT_DBG("Device waking up, queueing packet");
                /* Transient state; just keep packet for later */
                skb_queue_tail(&qca->tx_wait_q, skb);
                break;

        default:
                BT_ERR("Illegal tx state: %d (losing packet)",
                       qca->tx_ibs_state);
                kfree_skb(skb);
                break;
        }

        spin_unlock_irqrestore(&qca->hci_ibs_lock, flags);

        return 0;
}

static int qca_ibs_sleep_ind(struct hci_dev *hdev, struct sk_buff *skb)
{
        struct hci_uart *hu = hci_get_drvdata(hdev);

        BT_DBG("hu %p recv hci ibs cmd 0x%x", hu, HCI_IBS_SLEEP_IND);

        device_want_to_sleep(hu);

        kfree_skb(skb);
        return 0;
}

static int qca_ibs_wake_ind(struct hci_dev *hdev, struct sk_buff *skb)
{
        struct hci_uart *hu = hci_get_drvdata(hdev);

        BT_DBG("hu %p recv hci ibs cmd 0x%x", hu, HCI_IBS_WAKE_IND);

        device_want_to_wakeup(hu);

        kfree_skb(skb);
        return 0;
}

static int qca_ibs_wake_ack(struct hci_dev *hdev, struct sk_buff *skb)
{
        struct hci_uart *hu = hci_get_drvdata(hdev);

        BT_DBG("hu %p recv hci ibs cmd 0x%x", hu, HCI_IBS_WAKE_ACK);

        device_woke_up(hu);

        kfree_skb(skb);
        return 0;
}

#define QCA_IBS_SLEEP_IND_EVENT \
        .type = HCI_IBS_SLEEP_IND, \
        .hlen = 0, \
        .loff = 0, \
        .lsize = 0, \
        .maxlen = HCI_MAX_IBS_SIZE

#define QCA_IBS_WAKE_IND_EVENT \
        .type = HCI_IBS_WAKE_IND, \
        .hlen = 0, \
        .loff = 0, \
        .lsize = 0, \
        .maxlen = HCI_MAX_IBS_SIZE

#define QCA_IBS_WAKE_ACK_EVENT \
        .type = HCI_IBS_WAKE_ACK, \
        .hlen = 0, \
        .loff = 0, \
        .lsize = 0, \
        .maxlen = HCI_MAX_IBS_SIZE

static const struct h4_recv_pkt qca_recv_pkts[] = {
        { H4_RECV_ACL,             .recv = hci_recv_frame    },
        { H4_RECV_SCO,             .recv = hci_recv_frame    },
        { H4_RECV_EVENT,           .recv = hci_recv_frame    },
        { QCA_IBS_WAKE_IND_EVENT,  .recv = qca_ibs_wake_ind  },
        { QCA_IBS_WAKE_ACK_EVENT,  .recv = qca_ibs_wake_ack  },
        { QCA_IBS_SLEEP_IND_EVENT, .recv = qca_ibs_sleep_ind },
};

static int qca_recv(struct hci_uart *hu, const void *data, int count)
{
        struct qca_data *qca = hu->priv;

        if (!test_bit(HCI_UART_REGISTERED, &hu->flags))
                return -EUNATCH;

        qca->rx_skb = h4_recv_buf(hu->hdev, qca->rx_skb, data, count,
                                  qca_recv_pkts, ARRAY_SIZE(qca_recv_pkts));
        if (IS_ERR(qca->rx_skb)) {
                int err = PTR_ERR(qca->rx_skb);
                bt_dev_err(hu->hdev, "Frame reassembly failed (%d)", err);
                qca->rx_skb = NULL;
                return err;
        }

        return count;
}

static struct sk_buff *qca_dequeue(struct hci_uart *hu)
{
        struct qca_data *qca = hu->priv;

        return skb_dequeue(&qca->txq);
}

static uint8_t qca_get_baudrate_value(int speed)
{
        switch (speed) {
        case 9600:
                return QCA_BAUDRATE_9600;
        case 19200:
                return QCA_BAUDRATE_19200;
        case 38400:
                return QCA_BAUDRATE_38400;
        case 57600:
                return QCA_BAUDRATE_57600;
        case 115200:
                return QCA_BAUDRATE_115200;
        case 230400:
                return QCA_BAUDRATE_230400;
        case 460800:
                return QCA_BAUDRATE_460800;
        case 500000:
                return QCA_BAUDRATE_500000;
        case 921600:
                return QCA_BAUDRATE_921600;
        case 1000000:
                return QCA_BAUDRATE_1000000;
        case 2000000:
                return QCA_BAUDRATE_2000000;
        case 3000000:
                return QCA_BAUDRATE_3000000;
        case 3200000:
                return QCA_BAUDRATE_3200000;
        case 3500000:
                return QCA_BAUDRATE_3500000;
        default:
                return QCA_BAUDRATE_115200;
        }
}

static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
{
        struct hci_uart *hu = hci_get_drvdata(hdev);
        struct qca_data *qca = hu->priv;
        struct sk_buff *skb;
        struct qca_serdev *qcadev;
        u8 cmd[] = { 0x01, 0x48, 0xFC, 0x01, 0x00 };

        if (baudrate > QCA_BAUDRATE_3200000)
                return -EINVAL;

        cmd[4] = baudrate;

        skb = bt_skb_alloc(sizeof(cmd), GFP_KERNEL);
        if (!skb) {
                bt_dev_err(hdev, "Failed to allocate baudrate packet");
                return -ENOMEM;
        }

        /* Disabling hardware flow control is mandatory while
         * sending change baudrate request to wcn3990 SoC.
         */
        qcadev = serdev_device_get_drvdata(hu->serdev);
        if (qcadev->btsoc_type == QCA_WCN3990)
                hci_uart_set_flow_control(hu, true);

        /* Assign commands to change baudrate and packet type. */
        skb_put_data(skb, cmd, sizeof(cmd));
        hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;

        skb_queue_tail(&qca->txq, skb);
        hci_uart_tx_wakeup(hu);

        /* wait 300ms to change new baudrate on controller side
         * controller will come back after they receive this HCI command
         * then host can communicate with new baudrate to controller
         */
        set_current_state(TASK_UNINTERRUPTIBLE);
        schedule_timeout(msecs_to_jiffies(BAUDRATE_SETTLE_TIMEOUT_MS));
        set_current_state(TASK_RUNNING);

        if (qcadev->btsoc_type == QCA_WCN3990)
                hci_uart_set_flow_control(hu, false);

        return 0;
}

static inline void host_set_baudrate(struct hci_uart *hu, unsigned int speed)
{
        if (hu->serdev)
                serdev_device_set_baudrate(hu->serdev, speed);
        else
                hci_uart_set_baudrate(hu, speed);
}

static int qca_send_power_pulse(struct hci_dev *hdev, u8 cmd)
{
        struct hci_uart *hu = hci_get_drvdata(hdev);
        struct qca_data *qca = hu->priv;
        struct sk_buff *skb;

        /* These power pulses are single byte command which are sent
         * at required baudrate to wcn3990. On wcn3990, we have an external
         * circuit at Tx pin which decodes the pulse sent at specific baudrate.
         * For example, wcn3990 supports RF COEX antenna for both Wi-Fi/BT
         * and also we use the same power inputs to turn on and off for
         * Wi-Fi/BT. Powering up the power sources will not enable BT, until
         * we send a power on pulse at 115200 bps. This algorithm will help to
         * save power. Disabling hardware flow control is mandatory while
         * sending power pulses to SoC.
         */
        bt_dev_dbg(hdev, "sending power pulse %02x to SoC", cmd);

        skb = bt_skb_alloc(sizeof(cmd), GFP_KERNEL);
        if (!skb)
                return -ENOMEM;

        hci_uart_set_flow_control(hu, true);

        skb_put_u8(skb, cmd);
        hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;

        skb_queue_tail(&qca->txq, skb);
        hci_uart_tx_wakeup(hu);

        /* Wait for 100 uS for SoC to settle down */
        usleep_range(100, 200);
        hci_uart_set_flow_control(hu, false);

        return 0;
}

static unsigned int qca_get_speed(struct hci_uart *hu,
                                  enum qca_speed_type speed_type)
{
        unsigned int speed = 0;

        if (speed_type == QCA_INIT_SPEED) {
                if (hu->init_speed)
                        speed = hu->init_speed;
                else if (hu->proto->init_speed)
                        speed = hu->proto->init_speed;
        } else {
                if (hu->oper_speed)
                        speed = hu->oper_speed;
                else if (hu->proto->oper_speed)
                        speed = hu->proto->oper_speed;
        }

        return speed;
}

static int qca_check_speeds(struct hci_uart *hu)
{
        struct qca_serdev *qcadev;

        qcadev = serdev_device_get_drvdata(hu->serdev);
        if (qcadev->btsoc_type == QCA_WCN3990) {
                if (!qca_get_speed(hu, QCA_INIT_SPEED) &&
                    !qca_get_speed(hu, QCA_OPER_SPEED))
                        return -EINVAL;
        } else {
                if (!qca_get_speed(hu, QCA_INIT_SPEED) ||
                    !qca_get_speed(hu, QCA_OPER_SPEED))
                        return -EINVAL;
        }

        return 0;
}

static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type)
{
        unsigned int speed, qca_baudrate;
        int ret;

        if (speed_type == QCA_INIT_SPEED) {
                speed = qca_get_speed(hu, QCA_INIT_SPEED);
                if (speed)
                        host_set_baudrate(hu, speed);
        } else {
                speed = qca_get_speed(hu, QCA_OPER_SPEED);
                if (!speed)
                        return 0;

                qca_baudrate = qca_get_baudrate_value(speed);
                bt_dev_dbg(hu->hdev, "Set UART speed to %d", speed);
                ret = qca_set_baudrate(hu->hdev, qca_baudrate);
                if (ret)
                        return ret;

                host_set_baudrate(hu, speed);
        }

        return 0;
}

static int qca_wcn3990_init(struct hci_uart *hu)
{
        struct hci_dev *hdev = hu->hdev;
        int ret;

        /* Forcefully enable wcn3990 to enter in to boot mode. */
        host_set_baudrate(hu, 2400);
        ret = qca_send_power_pulse(hdev, QCA_WCN3990_POWEROFF_PULSE);
        if (ret)
                return ret;

        qca_set_speed(hu, QCA_INIT_SPEED);
        ret = qca_send_power_pulse(hdev, QCA_WCN3990_POWERON_PULSE);
        if (ret)
                return ret;

        /* Wait for 100 ms for SoC to boot */
        msleep(100);

        /* Now the device is in ready state to communicate with host.
         * To sync host with device we need to reopen port.
         * Without this, we will have RTS and CTS synchronization
         * issues.
         */
        serdev_device_close(hu->serdev);
        ret = serdev_device_open(hu->serdev);
        if (ret) {
                bt_dev_err(hu->hdev, "failed to open port");
                return ret;
        }

        hci_uart_set_flow_control(hu, false);

        return 0;
}

static int qca_setup(struct hci_uart *hu)
{
        struct hci_dev *hdev = hu->hdev;
        struct qca_data *qca = hu->priv;
        unsigned int speed, qca_baudrate = QCA_BAUDRATE_115200;
        struct qca_serdev *qcadev;
        int ret;
        int soc_ver = 0;

        qcadev = serdev_device_get_drvdata(hu->serdev);

        ret = qca_check_speeds(hu);
        if (ret)
                return ret;

        /* Patch downloading has to be done without IBS mode */
        clear_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);

        if (qcadev->btsoc_type == QCA_WCN3990) {
                bt_dev_info(hdev, "setting up wcn3990");
                ret = qca_wcn3990_init(hu);
                if (ret)
                        return ret;

                ret = qca_read_soc_version(hdev, &soc_ver);
                if (ret)
                        return ret;
        } else {
                bt_dev_info(hdev, "ROME setup");
                qca_set_speed(hu, QCA_INIT_SPEED);
        }

        /* Setup user speed if needed */
        speed = qca_get_speed(hu, QCA_OPER_SPEED);
        if (speed) {
                ret = qca_set_speed(hu, QCA_OPER_SPEED);
                if (ret)
                        return ret;

                qca_baudrate = qca_get_baudrate_value(speed);
        }

        if (qcadev->btsoc_type != QCA_WCN3990) {
                /* Get QCA version information */
                ret = qca_read_soc_version(hdev, &soc_ver);
                if (ret)
                        return ret;
        }

        bt_dev_info(hdev, "QCA controller version 0x%08x", soc_ver);
        /* Setup patch / NVM configurations */
        ret = qca_uart_setup(hdev, qca_baudrate, qcadev->btsoc_type, soc_ver);
        if (!ret) {
                set_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
                qca_debugfs_init(hdev);
        } else if (ret == -ENOENT) {
                /* No patch/nvm-config found, run with original fw/config */
                ret = 0;
        } else if (ret == -EAGAIN) {
                /*
                 * Userspace firmware loader will return -EAGAIN in case no
                 * patch/nvm-config is found, so run with original fw/config.
                 */
                ret = 0;
        }

        /* Setup bdaddr */
        hu->hdev->set_bdaddr = qca_set_bdaddr_rome;

        return ret;
}

static struct hci_uart_proto qca_proto = {
        .id             = HCI_UART_QCA,
        .name           = "QCA",
        .manufacturer   = 29,
        .init_speed     = 115200,
        .oper_speed     = 3000000,
        .open           = qca_open,
        .close          = qca_close,
        .flush          = qca_flush,
        .setup          = qca_setup,
        .recv           = qca_recv,
        .enqueue        = qca_enqueue,
        .dequeue        = qca_dequeue,
};

static const struct qca_vreg_data qca_soc_data = {
        .soc_type = QCA_WCN3990,
        .vregs = (struct qca_vreg []) {
                { "vddio",   1800000, 1900000,  15000  },
                { "vddxo",   1800000, 1900000,  80000  },
                { "vddrf",   1300000, 1350000,  300000 },
                { "vddch0",  3300000, 3400000,  450000 },
        },
        .num_vregs = 4,
};

static void qca_power_shutdown(struct hci_dev *hdev)
{
        struct hci_uart *hu = hci_get_drvdata(hdev);

        host_set_baudrate(hu, 2400);
        qca_send_power_pulse(hdev, QCA_WCN3990_POWEROFF_PULSE);
        qca_power_setup(hu, false);
}

static int qca_enable_regulator(struct qca_vreg vregs,
                                struct regulator *regulator)
{
        int ret;

        ret = regulator_set_voltage(regulator, vregs.min_uV,
                                    vregs.max_uV);
        if (ret)
                return ret;

        if (vregs.load_uA)
                ret = regulator_set_load(regulator,
                                         vregs.load_uA);

        if (ret)
                return ret;

        return regulator_enable(regulator);

}

static void qca_disable_regulator(struct qca_vreg vregs,
                                  struct regulator *regulator)
{
        regulator_disable(regulator);
        regulator_set_voltage(regulator, 0, vregs.max_uV);
        if (vregs.load_uA)
                regulator_set_load(regulator, 0);

}

static int qca_power_setup(struct hci_uart *hu, bool on)
{
        struct qca_vreg *vregs;
        struct regulator_bulk_data *vreg_bulk;
        struct qca_serdev *qcadev;
        int i, num_vregs, ret = 0;

        qcadev = serdev_device_get_drvdata(hu->serdev);
        if (!qcadev || !qcadev->bt_power || !qcadev->bt_power->vreg_data ||
            !qcadev->bt_power->vreg_bulk)
                return -EINVAL;

        vregs = qcadev->bt_power->vreg_data->vregs;
        vreg_bulk = qcadev->bt_power->vreg_bulk;
        num_vregs = qcadev->bt_power->vreg_data->num_vregs;
        BT_DBG("on: %d", on);
        if (on && !qcadev->bt_power->vregs_on) {
                for (i = 0; i < num_vregs; i++) {
                        ret = qca_enable_regulator(vregs[i],
                                                   vreg_bulk[i].consumer);
                        if (ret)
                                break;
                }

                if (ret) {
                        BT_ERR("failed to enable regulator:%s", vregs[i].name);
                        /* turn off regulators which are enabled */
                        for (i = i - 1; i >= 0; i--)
                                qca_disable_regulator(vregs[i],
                                                      vreg_bulk[i].consumer);
                } else {
                        qcadev->bt_power->vregs_on = true;
                }
        } else if (!on && qcadev->bt_power->vregs_on) {
                /* turn off regulator in reverse order */
                i = qcadev->bt_power->vreg_data->num_vregs - 1;
                for ( ; i >= 0; i--)
                        qca_disable_regulator(vregs[i], vreg_bulk[i].consumer);

                qcadev->bt_power->vregs_on = false;
        }

        return ret;
}

static int qca_init_regulators(struct qca_power *qca,
                                const struct qca_vreg *vregs, size_t num_vregs)
{
        int i;

        qca->vreg_bulk = devm_kzalloc(qca->dev, num_vregs *
                                      sizeof(struct regulator_bulk_data),
                                      GFP_KERNEL);
        if (!qca->vreg_bulk)
                return -ENOMEM;

        for (i = 0; i < num_vregs; i++)
                qca->vreg_bulk[i].supply = vregs[i].name;

        return devm_regulator_bulk_get(qca->dev, num_vregs, qca->vreg_bulk);
}

static int qca_serdev_probe(struct serdev_device *serdev)
{
        struct qca_serdev *qcadev;
        const struct qca_vreg_data *data;
        int err;

        qcadev = devm_kzalloc(&serdev->dev, sizeof(*qcadev), GFP_KERNEL);
        if (!qcadev)
                return -ENOMEM;

        qcadev->serdev_hu.serdev = serdev;
        data = of_device_get_match_data(&serdev->dev);
        serdev_device_set_drvdata(serdev, qcadev);
        if (data && data->soc_type == QCA_WCN3990) {
                qcadev->btsoc_type = QCA_WCN3990;
                qcadev->bt_power = devm_kzalloc(&serdev->dev,
                                                sizeof(struct qca_power),
                                                GFP_KERNEL);
                if (!qcadev->bt_power)
                        return -ENOMEM;

                qcadev->bt_power->dev = &serdev->dev;
                qcadev->bt_power->vreg_data = data;
                err = qca_init_regulators(qcadev->bt_power, data->vregs,
                                          data->num_vregs);
                if (err) {
                        BT_ERR("Failed to init regulators:%d", err);
                        goto out;
                }

                qcadev->bt_power->vregs_on = false;

                device_property_read_u32(&serdev->dev, "max-speed",
                                         &qcadev->oper_speed);
                if (!qcadev->oper_speed)
                        BT_DBG("UART will pick default operating speed");

                err = hci_uart_register_device(&qcadev->serdev_hu, &qca_proto);
                if (err) {
                        BT_ERR("wcn3990 serdev registration failed");
                        goto out;
                }
        } else {
                qcadev->btsoc_type = QCA_ROME;
                qcadev->bt_en = devm_gpiod_get(&serdev->dev, "enable",
                                               GPIOD_OUT_LOW);
                if (IS_ERR(qcadev->bt_en)) {
                        dev_err(&serdev->dev, "failed to acquire enable gpio\n");
                        return PTR_ERR(qcadev->bt_en);
                }

                qcadev->susclk = devm_clk_get(&serdev->dev, NULL);
                if (IS_ERR(qcadev->susclk)) {
                        dev_err(&serdev->dev, "failed to acquire clk\n");
                        return PTR_ERR(qcadev->susclk);
                }

                err = clk_set_rate(qcadev->susclk, SUSCLK_RATE_32KHZ);
                if (err)
                        return err;

                err = clk_prepare_enable(qcadev->susclk);
                if (err)
                        return err;

                err = hci_uart_register_device(&qcadev->serdev_hu, &qca_proto);
                if (err)
                        clk_disable_unprepare(qcadev->susclk);
        }

out:    return err;

}

static void qca_serdev_remove(struct serdev_device *serdev)
{
        struct qca_serdev *qcadev = serdev_device_get_drvdata(serdev);

        if (qcadev->btsoc_type == QCA_WCN3990)
                qca_power_shutdown(qcadev->serdev_hu.hdev);
        else
                clk_disable_unprepare(qcadev->susclk);

        hci_uart_unregister_device(&qcadev->serdev_hu);
}

static const struct of_device_id qca_bluetooth_of_match[] = {
        { .compatible = "qcom,qca6174-bt" },
        { .compatible = "qcom,wcn3990-bt", .data = &qca_soc_data},
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, qca_bluetooth_of_match);

static struct serdev_device_driver qca_serdev_driver = {
        .probe = qca_serdev_probe,
        .remove = qca_serdev_remove,
        .driver = {
                .name = "hci_uart_qca",
                .of_match_table = qca_bluetooth_of_match,
        },
};

int __init qca_init(void)
{
        serdev_device_driver_register(&qca_serdev_driver);

        return hci_uart_register_proto(&qca_proto);
}

int __exit qca_deinit(void)
{
        serdev_device_driver_unregister(&qca_serdev_driver);

        return hci_uart_unregister_proto(&qca_proto);
}