// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 *  Bluetooth HCI UART driver for Intel devices
 *
 *  Copyright (C) 2015  Intel Corporation
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/firmware.h>
#include <linux/module.h>
#include <linux/wait.h>
#include <linux/tty.h>
#include <linux/platform_device.h>
#include <linux/gpio/consumer.h>
#include <linux/acpi.h>
#include <linux/interrupt.h>
#include <linux/pm_runtime.h>

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

#include "hci_uart.h"
#include "btintel.h"

#define STATE_BOOTLOADER        0
#define STATE_DOWNLOADING       1
#define STATE_FIRMWARE_LOADED   2
#define STATE_FIRMWARE_FAILED   3
#define STATE_BOOTING           4
#define STATE_LPM_ENABLED       5
#define STATE_TX_ACTIVE         6
#define STATE_SUSPENDED         7
#define STATE_LPM_TRANSACTION   8

#define HCI_LPM_WAKE_PKT 0xf0
#define HCI_LPM_PKT 0xf1
#define HCI_LPM_MAX_SIZE 10
#define HCI_LPM_HDR_SIZE HCI_EVENT_HDR_SIZE

#define LPM_OP_TX_NOTIFY 0x00
#define LPM_OP_SUSPEND_ACK 0x02
#define LPM_OP_RESUME_ACK 0x03

#define LPM_SUSPEND_DELAY_MS 1000

struct hci_lpm_pkt {
        __u8 opcode;
        __u8 dlen;
        __u8 data[];
} __packed;

struct intel_device {
        struct list_head list;
        struct platform_device *pdev;
        struct gpio_desc *reset;
        struct hci_uart *hu;
        struct mutex hu_lock;
        int irq;
};

static LIST_HEAD(intel_device_list);
static DEFINE_MUTEX(intel_device_list_lock);

struct intel_data {
        struct sk_buff *rx_skb;
        struct sk_buff_head txq;
        struct work_struct busy_work;
        struct hci_uart *hu;
        unsigned long flags;
};

static u8 intel_convert_speed(unsigned int speed)
{
        switch (speed) {
        case 9600:
                return 0x00;
        case 19200:
                return 0x01;
        case 38400:
                return 0x02;
        case 57600:
                return 0x03;
        case 115200:
                return 0x04;
        case 230400:
                return 0x05;
        case 460800:
                return 0x06;
        case 921600:
                return 0x07;
        case 1843200:
                return 0x08;
        case 3250000:
                return 0x09;
        case 2000000:
                return 0x0a;
        case 3000000:
                return 0x0b;
        default:
                return 0xff;
        }
}

static int intel_wait_booting(struct hci_uart *hu)
{
        struct intel_data *intel = hu->priv;
        int err;

        err = wait_on_bit_timeout(&intel->flags, STATE_BOOTING,
                                  TASK_INTERRUPTIBLE,
                                  msecs_to_jiffies(1000));

        if (err == -EINTR) {
                bt_dev_err(hu->hdev, "Device boot interrupted");
                return -EINTR;
        }

        if (err) {
                bt_dev_err(hu->hdev, "Device boot timeout");
                return -ETIMEDOUT;
        }

        return err;
}

static int intel_wait_lpm_transaction(struct hci_uart *hu)
{
        struct intel_data *intel = hu->priv;
        int err;

        err = wait_on_bit_timeout(&intel->flags, STATE_LPM_TRANSACTION,
                                  TASK_INTERRUPTIBLE,
                                  msecs_to_jiffies(1000));

        if (err == -EINTR) {
                bt_dev_err(hu->hdev, "LPM transaction interrupted");
                return -EINTR;
        }

        if (err) {
                bt_dev_err(hu->hdev, "LPM transaction timeout");
                return -ETIMEDOUT;
        }

        return err;
}

static int intel_lpm_suspend(struct hci_uart *hu)
{
        static const u8 suspend[] = { 0x01, 0x01, 0x01 };
        struct intel_data *intel = hu->priv;
        struct sk_buff *skb;

        if (!test_bit(STATE_LPM_ENABLED, &intel->flags) ||
            test_bit(STATE_SUSPENDED, &intel->flags))
                return 0;

        if (test_bit(STATE_TX_ACTIVE, &intel->flags))
                return -EAGAIN;

        bt_dev_dbg(hu->hdev, "Suspending");

        skb = bt_skb_alloc(sizeof(suspend), GFP_KERNEL);
        if (!skb) {
                bt_dev_err(hu->hdev, "Failed to alloc memory for LPM packet");
                return -ENOMEM;
        }

        skb_put_data(skb, suspend, sizeof(suspend));
        hci_skb_pkt_type(skb) = HCI_LPM_PKT;

        set_bit(STATE_LPM_TRANSACTION, &intel->flags);

        /* LPM flow is a priority, enqueue packet at list head */
        skb_queue_head(&intel->txq, skb);
        hci_uart_tx_wakeup(hu);

        intel_wait_lpm_transaction(hu);
        /* Even in case of failure, continue and test the suspended flag */

        clear_bit(STATE_LPM_TRANSACTION, &intel->flags);

        if (!test_bit(STATE_SUSPENDED, &intel->flags)) {
                bt_dev_err(hu->hdev, "Device suspend error");
                return -EINVAL;
        }

        bt_dev_dbg(hu->hdev, "Suspended");

        hci_uart_set_flow_control(hu, true);

        return 0;
}

static int intel_lpm_resume(struct hci_uart *hu)
{
        struct intel_data *intel = hu->priv;
        struct sk_buff *skb;

        if (!test_bit(STATE_LPM_ENABLED, &intel->flags) ||
            !test_bit(STATE_SUSPENDED, &intel->flags))
                return 0;

        bt_dev_dbg(hu->hdev, "Resuming");

        hci_uart_set_flow_control(hu, false);

        skb = bt_skb_alloc(0, GFP_KERNEL);
        if (!skb) {
                bt_dev_err(hu->hdev, "Failed to alloc memory for LPM packet");
                return -ENOMEM;
        }

        hci_skb_pkt_type(skb) = HCI_LPM_WAKE_PKT;

        set_bit(STATE_LPM_TRANSACTION, &intel->flags);

        /* LPM flow is a priority, enqueue packet at list head */
        skb_queue_head(&intel->txq, skb);
        hci_uart_tx_wakeup(hu);

        intel_wait_lpm_transaction(hu);
        /* Even in case of failure, continue and test the suspended flag */

        clear_bit(STATE_LPM_TRANSACTION, &intel->flags);

        if (test_bit(STATE_SUSPENDED, &intel->flags)) {
                bt_dev_err(hu->hdev, "Device resume error");
                return -EINVAL;
        }

        bt_dev_dbg(hu->hdev, "Resumed");

        return 0;
}

static int intel_lpm_host_wake(struct hci_uart *hu)
{
        static const u8 lpm_resume_ack[] = { LPM_OP_RESUME_ACK, 0x00 };
        struct intel_data *intel = hu->priv;
        struct sk_buff *skb;

        hci_uart_set_flow_control(hu, false);

        clear_bit(STATE_SUSPENDED, &intel->flags);

        skb = bt_skb_alloc(sizeof(lpm_resume_ack), GFP_KERNEL);
        if (!skb) {
                bt_dev_err(hu->hdev, "Failed to alloc memory for LPM packet");
                return -ENOMEM;
        }

        skb_put_data(skb, lpm_resume_ack, sizeof(lpm_resume_ack));
        hci_skb_pkt_type(skb) = HCI_LPM_PKT;

        /* LPM flow is a priority, enqueue packet at list head */
        skb_queue_head(&intel->txq, skb);
        hci_uart_tx_wakeup(hu);

        bt_dev_dbg(hu->hdev, "Resumed by controller");

        return 0;
}

static irqreturn_t intel_irq(int irq, void *dev_id)
{
        struct intel_device *idev = dev_id;

        dev_info(&idev->pdev->dev, "hci_intel irq\n");

        mutex_lock(&idev->hu_lock);
        if (idev->hu)
                intel_lpm_host_wake(idev->hu);
        mutex_unlock(&idev->hu_lock);

        /* Host/Controller are now LPM resumed, trigger a new delayed suspend */
        pm_runtime_get(&idev->pdev->dev);
        pm_runtime_put_autosuspend(&idev->pdev->dev);

        return IRQ_HANDLED;
}

static int intel_set_power(struct hci_uart *hu, bool powered)
{
        struct intel_device *idev;
        int err = -ENODEV;

        if (!hu->tty->dev)
                return err;

        mutex_lock(&intel_device_list_lock);

        list_for_each_entry(idev, &intel_device_list, list) {
                /* tty device and pdev device should share the same parent
                 * which is the UART port.
                 */
                if (hu->tty->dev->parent != idev->pdev->dev.parent)
                        continue;

                if (!idev->reset) {
                        err = -ENOTSUPP;
                        break;
                }

                BT_INFO("hu %p, Switching compatible pm device (%s) to %u",
                        hu, dev_name(&idev->pdev->dev), powered);

                gpiod_set_value(idev->reset, powered);

                /* Provide to idev a hu reference which is used to run LPM
                 * transactions (lpm suspend/resume) from PM callbacks.
                 * hu needs to be protected against concurrent removing during
                 * these PM ops.
                 */
                mutex_lock(&idev->hu_lock);
                idev->hu = powered ? hu : NULL;
                mutex_unlock(&idev->hu_lock);

                if (idev->irq < 0)
                        break;

                if (powered && device_can_wakeup(&idev->pdev->dev)) {
                        err = devm_request_threaded_irq(&idev->pdev->dev,
                                                        idev->irq, NULL,
                                                        intel_irq,
                                                        IRQF_ONESHOT,
                                                        "bt-host-wake", idev);
                        if (err) {
                                BT_ERR("hu %p, unable to allocate irq-%d",
                                       hu, idev->irq);
                                break;
                        }

                        device_wakeup_enable(&idev->pdev->dev);

                        pm_runtime_set_active(&idev->pdev->dev);
                        pm_runtime_use_autosuspend(&idev->pdev->dev);
                        pm_runtime_set_autosuspend_delay(&idev->pdev->dev,
                                                         LPM_SUSPEND_DELAY_MS);
                        pm_runtime_enable(&idev->pdev->dev);
                } else if (!powered && device_may_wakeup(&idev->pdev->dev)) {
                        devm_free_irq(&idev->pdev->dev, idev->irq, idev);
                        device_wakeup_disable(&idev->pdev->dev);

                        pm_runtime_disable(&idev->pdev->dev);
                }
        }

        mutex_unlock(&intel_device_list_lock);

        return err;
}

static void intel_busy_work(struct work_struct *work)
{
        struct intel_data *intel = container_of(work, struct intel_data,
                                                busy_work);
        struct intel_device *idev;

        if (!intel->hu->tty->dev)
                return;

        /* Link is busy, delay the suspend */
        mutex_lock(&intel_device_list_lock);
        list_for_each_entry(idev, &intel_device_list, list) {
                if (intel->hu->tty->dev->parent == idev->pdev->dev.parent) {
                        pm_runtime_get(&idev->pdev->dev);
                        pm_runtime_put_autosuspend(&idev->pdev->dev);
                        break;
                }
        }
        mutex_unlock(&intel_device_list_lock);
}

static int intel_open(struct hci_uart *hu)
{
        struct intel_data *intel;

        BT_DBG("hu %p", hu);

        if (!hci_uart_has_flow_control(hu))
                return -EOPNOTSUPP;

        intel = kzalloc_obj(*intel);
        if (!intel)
                return -ENOMEM;

        skb_queue_head_init(&intel->txq);
        INIT_WORK(&intel->busy_work, intel_busy_work);

        intel->hu = hu;

        hu->priv = intel;

        if (!intel_set_power(hu, true))
                set_bit(STATE_BOOTING, &intel->flags);

        return 0;
}

static int intel_close(struct hci_uart *hu)
{
        struct intel_data *intel = hu->priv;

        BT_DBG("hu %p", hu);

        cancel_work_sync(&intel->busy_work);

        intel_set_power(hu, false);

        skb_queue_purge(&intel->txq);
        kfree_skb(intel->rx_skb);
        kfree(intel);

        hu->priv = NULL;
        return 0;
}

static int intel_flush(struct hci_uart *hu)
{
        struct intel_data *intel = hu->priv;

        BT_DBG("hu %p", hu);

        skb_queue_purge(&intel->txq);

        return 0;
}

static int inject_cmd_complete(struct hci_dev *hdev, __u16 opcode)
{
        struct sk_buff *skb;
        struct hci_event_hdr *hdr;
        struct hci_ev_cmd_complete *evt;

        skb = bt_skb_alloc(sizeof(*hdr) + sizeof(*evt) + 1, GFP_KERNEL);
        if (!skb)
                return -ENOMEM;

        hdr = skb_put(skb, sizeof(*hdr));
        hdr->evt = HCI_EV_CMD_COMPLETE;
        hdr->plen = sizeof(*evt) + 1;

        evt = skb_put(skb, sizeof(*evt));
        evt->ncmd = 0x01;
        evt->opcode = cpu_to_le16(opcode);

        skb_put_u8(skb, 0x00);

        hci_skb_pkt_type(skb) = HCI_EVENT_PKT;

        return hci_recv_frame(hdev, skb);
}

static int intel_set_baudrate(struct hci_uart *hu, unsigned int speed)
{
        struct intel_data *intel = hu->priv;
        struct hci_dev *hdev = hu->hdev;
        u8 speed_cmd[] = { 0x06, 0xfc, 0x01, 0x00 };
        struct sk_buff *skb;
        int err;

        /* This can be the first command sent to the chip, check
         * that the controller is ready.
         */
        err = intel_wait_booting(hu);

        clear_bit(STATE_BOOTING, &intel->flags);

        /* In case of timeout, try to continue anyway */
        if (err && err != -ETIMEDOUT)
                return err;

        bt_dev_info(hdev, "Change controller speed to %d", speed);

        speed_cmd[3] = intel_convert_speed(speed);
        if (speed_cmd[3] == 0xff) {
                bt_dev_err(hdev, "Unsupported speed");
                return -EINVAL;
        }

        /* Device will not accept speed change if Intel version has not been
         * previously requested.
         */
        skb = __hci_cmd_sync(hdev, 0xfc05, 0, NULL, HCI_CMD_TIMEOUT);
        if (IS_ERR(skb)) {
                bt_dev_err(hdev, "Reading Intel version information failed (%ld)",
                           PTR_ERR(skb));
                return PTR_ERR(skb);
        }
        kfree_skb(skb);

        skb = bt_skb_alloc(sizeof(speed_cmd), GFP_KERNEL);
        if (!skb) {
                bt_dev_err(hdev, "Failed to alloc memory for baudrate packet");
                return -ENOMEM;
        }

        skb_put_data(skb, speed_cmd, sizeof(speed_cmd));
        hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;

        hci_uart_set_flow_control(hu, true);

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

        /* wait 100ms to change baudrate on controller side */
        msleep(100);

        hci_uart_set_baudrate(hu, speed);
        hci_uart_set_flow_control(hu, false);

        return 0;
}

static int intel_setup(struct hci_uart *hu)
{
        struct intel_data *intel = hu->priv;
        struct hci_dev *hdev = hu->hdev;
        struct sk_buff *skb;
        struct intel_version ver;
        struct intel_boot_params params;
        struct intel_device *idev;
        const struct firmware *fw;
        char fwname[64];
        u32 boot_param;
        ktime_t calltime, delta, rettime;
        unsigned long long duration;
        unsigned int init_speed, oper_speed;
        int speed_change = 0;
        int err;

        bt_dev_dbg(hdev, "");

        hu->hdev->set_diag = btintel_set_diag;
        hu->hdev->set_bdaddr = btintel_set_bdaddr;

        /* Set the default boot parameter to 0x0 and it is updated to
         * SKU specific boot parameter after reading Intel_Write_Boot_Params
         * command while downloading the firmware.
         */
        boot_param = 0x00000000;

        calltime = ktime_get();

        if (hu->init_speed)
                init_speed = hu->init_speed;
        else
                init_speed = hu->proto->init_speed;

        if (hu->oper_speed)
                oper_speed = hu->oper_speed;
        else
                oper_speed = hu->proto->oper_speed;

        if (oper_speed && init_speed && oper_speed != init_speed)
                speed_change = 1;

        /* Check that the controller is ready */
        err = intel_wait_booting(hu);

        clear_bit(STATE_BOOTING, &intel->flags);

        /* In case of timeout, try to continue anyway */
        if (err && err != -ETIMEDOUT)
                return err;

        set_bit(STATE_BOOTLOADER, &intel->flags);

        /* Read the Intel version information to determine if the device
         * is in bootloader mode or if it already has operational firmware
         * loaded.
         */
        err = btintel_read_version(hdev, &ver);
        if (err)
                return err;

        /* The hardware platform number has a fixed value of 0x37 and
         * for now only accept this single value.
         */
        if (ver.hw_platform != 0x37) {
                bt_dev_err(hdev, "Unsupported Intel hardware platform (%u)",
                           ver.hw_platform);
                return -EINVAL;
        }

        /* Check for supported iBT hardware variants of this firmware
         * loading method.
         *
         * This check has been put in place to ensure correct forward
         * compatibility options when newer hardware variants come along.
         */
        switch (ver.hw_variant) {
        case 0x0b:      /* LnP */
        case 0x0c:      /* WsP */
        case 0x12:      /* ThP */
                break;
        default:
                bt_dev_err(hdev, "Unsupported Intel hardware variant (%u)",
                           ver.hw_variant);
                return -EINVAL;
        }

        btintel_version_info(hdev, &ver);

        /* The firmware variant determines if the device is in bootloader
         * mode or is running operational firmware. The value 0x06 identifies
         * the bootloader and the value 0x23 identifies the operational
         * firmware.
         *
         * When the operational firmware is already present, then only
         * the check for valid Bluetooth device address is needed. This
         * determines if the device will be added as configured or
         * unconfigured controller.
         *
         * It is not possible to use the Secure Boot Parameters in this
         * case since that command is only available in bootloader mode.
         */
        if (ver.fw_variant == 0x23) {
                clear_bit(STATE_BOOTLOADER, &intel->flags);
                btintel_check_bdaddr(hdev);
                return 0;
        }

        /* If the device is not in bootloader mode, then the only possible
         * choice is to return an error and abort the device initialization.
         */
        if (ver.fw_variant != 0x06) {
                bt_dev_err(hdev, "Unsupported Intel firmware variant (%u)",
                           ver.fw_variant);
                return -ENODEV;
        }

        /* Read the secure boot parameters to identify the operating
         * details of the bootloader.
         */
        err = btintel_read_boot_params(hdev, &params);
        if (err)
                return err;

        /* It is required that every single firmware fragment is acknowledged
         * with a command complete event. If the boot parameters indicate
         * that this bootloader does not send them, then abort the setup.
         */
        if (params.limited_cce != 0x00) {
                bt_dev_err(hdev, "Unsupported Intel firmware loading method (%u)",
                           params.limited_cce);
                return -EINVAL;
        }

        /* If the OTP has no valid Bluetooth device address, then there will
         * also be no valid address for the operational firmware.
         */
        if (!bacmp(&params.otp_bdaddr, BDADDR_ANY)) {
                bt_dev_info(hdev, "No device address configured");
                hci_set_quirk(hdev, HCI_QUIRK_INVALID_BDADDR);
        }

        /* With this Intel bootloader only the hardware variant and device
         * revision information are used to select the right firmware for SfP
         * and WsP.
         *
         * The firmware filename is ibt-<hw_variant>-<dev_revid>.sfi.
         *
         * Currently the supported hardware variants are:
         *   11 (0x0b) for iBT 3.0 (LnP/SfP)
         *   12 (0x0c) for iBT 3.5 (WsP)
         *
         * For ThP/JfP and for future SKU's, the FW name varies based on HW
         * variant, HW revision and FW revision, as these are dependent on CNVi
         * and RF Combination.
         *
         *   18 (0x12) for iBT3.5 (ThP/JfP)
         *
         * The firmware file name for these will be
         * ibt-<hw_variant>-<hw_revision>-<fw_revision>.sfi.
         *
         */
        switch (ver.hw_variant) {
        case 0x0b:      /* SfP */
        case 0x0c:      /* WsP */
                snprintf(fwname, sizeof(fwname), "intel/ibt-%u-%u.sfi",
                         ver.hw_variant, le16_to_cpu(params.dev_revid));
                break;
        case 0x12:      /* ThP */
                snprintf(fwname, sizeof(fwname), "intel/ibt-%u-%u-%u.sfi",
                         ver.hw_variant, ver.hw_revision, ver.fw_revision);
                break;
        default:
                bt_dev_err(hdev, "Unsupported Intel hardware variant (%u)",
                           ver.hw_variant);
                return -EINVAL;
        }

        err = request_firmware(&fw, fwname, &hdev->dev);
        if (err < 0) {
                bt_dev_err(hdev, "Failed to load Intel firmware file (%d)",
                           err);
                return err;
        }

        bt_dev_info(hdev, "Found device firmware: %s", fwname);

        /* Save the DDC file name for later */
        switch (ver.hw_variant) {
        case 0x0b:      /* SfP */
        case 0x0c:      /* WsP */
                snprintf(fwname, sizeof(fwname), "intel/ibt-%u-%u.ddc",
                         ver.hw_variant, le16_to_cpu(params.dev_revid));
                break;
        case 0x12:      /* ThP */
                snprintf(fwname, sizeof(fwname), "intel/ibt-%u-%u-%u.ddc",
                         ver.hw_variant, ver.hw_revision, ver.fw_revision);
                break;
        default:
                bt_dev_err(hdev, "Unsupported Intel hardware variant (%u)",
                           ver.hw_variant);
                return -EINVAL;
        }

        if (fw->size < 644) {
                bt_dev_err(hdev, "Invalid size of firmware file (%zu)",
                           fw->size);
                err = -EBADF;
                goto done;
        }

        set_bit(STATE_DOWNLOADING, &intel->flags);

        /* Start firmware downloading and get boot parameter */
        err = btintel_download_firmware(hdev, &ver, fw, &boot_param);
        if (err < 0)
                goto done;

        set_bit(STATE_FIRMWARE_LOADED, &intel->flags);

        bt_dev_info(hdev, "Waiting for firmware download to complete");

        /* Before switching the device into operational mode and with that
         * booting the loaded firmware, wait for the bootloader notification
         * that all fragments have been successfully received.
         *
         * When the event processing receives the notification, then the
         * STATE_DOWNLOADING flag will be cleared.
         *
         * The firmware loading should not take longer than 5 seconds
         * and thus just timeout if that happens and fail the setup
         * of this device.
         */
        err = wait_on_bit_timeout(&intel->flags, STATE_DOWNLOADING,
                                  TASK_INTERRUPTIBLE,
                                  msecs_to_jiffies(5000));
        if (err == -EINTR) {
                bt_dev_err(hdev, "Firmware loading interrupted");
                err = -EINTR;
                goto done;
        }

        if (err) {
                bt_dev_err(hdev, "Firmware loading timeout");
                err = -ETIMEDOUT;
                goto done;
        }

        if (test_bit(STATE_FIRMWARE_FAILED, &intel->flags)) {
                bt_dev_err(hdev, "Firmware loading failed");
                err = -ENOEXEC;
                goto done;
        }

        rettime = ktime_get();
        delta = ktime_sub(rettime, calltime);
        duration = (unsigned long long)ktime_to_ns(delta) >> 10;

        bt_dev_info(hdev, "Firmware loaded in %llu usecs", duration);

done:
        release_firmware(fw);

        /* Check if there was an error and if is not -EALREADY which means the
         * firmware has already been loaded.
         */
        if (err < 0 && err != -EALREADY)
                return err;

        /* We need to restore the default speed before Intel reset */
        if (speed_change) {
                err = intel_set_baudrate(hu, init_speed);
                if (err)
                        return err;
        }

        calltime = ktime_get();

        set_bit(STATE_BOOTING, &intel->flags);

        err = btintel_send_intel_reset(hdev, boot_param);
        if (err)
                return err;

        /* The bootloader will not indicate when the device is ready. This
         * is done by the operational firmware sending bootup notification.
         *
         * Booting into operational firmware should not take longer than
         * 1 second. However if that happens, then just fail the setup
         * since something went wrong.
         */
        bt_dev_info(hdev, "Waiting for device to boot");

        err = intel_wait_booting(hu);
        if (err)
                return err;

        clear_bit(STATE_BOOTING, &intel->flags);

        rettime = ktime_get();
        delta = ktime_sub(rettime, calltime);
        duration = (unsigned long long)ktime_to_ns(delta) >> 10;

        bt_dev_info(hdev, "Device booted in %llu usecs", duration);

        /* Enable LPM if matching pdev with wakeup enabled, set TX active
         * until further LPM TX notification.
         */
        mutex_lock(&intel_device_list_lock);
        list_for_each_entry(idev, &intel_device_list, list) {
                if (!hu->tty->dev)
                        break;
                if (hu->tty->dev->parent == idev->pdev->dev.parent) {
                        if (device_may_wakeup(&idev->pdev->dev)) {
                                set_bit(STATE_LPM_ENABLED, &intel->flags);
                                set_bit(STATE_TX_ACTIVE, &intel->flags);
                        }
                        break;
                }
        }
        mutex_unlock(&intel_device_list_lock);

        /* Ignore errors, device can work without DDC parameters */
        btintel_load_ddc_config(hdev, fwname);

        skb = __hci_cmd_sync(hdev, HCI_OP_RESET, 0, NULL, HCI_CMD_TIMEOUT);
        if (IS_ERR(skb))
                return PTR_ERR(skb);
        kfree_skb(skb);

        if (speed_change) {
                err = intel_set_baudrate(hu, oper_speed);
                if (err)
                        return err;
        }

        bt_dev_info(hdev, "Setup complete");

        clear_bit(STATE_BOOTLOADER, &intel->flags);

        return 0;
}

static int intel_recv_event(struct hci_dev *hdev, struct sk_buff *skb)
{
        struct hci_uart *hu = hci_get_drvdata(hdev);
        struct intel_data *intel = hu->priv;
        struct hci_event_hdr *hdr;

        if (!test_bit(STATE_BOOTLOADER, &intel->flags) &&
            !test_bit(STATE_BOOTING, &intel->flags))
                goto recv;

        hdr = (void *)skb->data;

        /* When the firmware loading completes the device sends
         * out a vendor specific event indicating the result of
         * the firmware loading.
         */
        if (skb->len == 7 && hdr->evt == 0xff && hdr->plen == 0x05 &&
            skb->data[2] == 0x06) {
                if (skb->data[3] != 0x00)
                        set_bit(STATE_FIRMWARE_FAILED, &intel->flags);

                if (test_and_clear_bit(STATE_DOWNLOADING, &intel->flags) &&
                    test_bit(STATE_FIRMWARE_LOADED, &intel->flags))
                        wake_up_bit(&intel->flags, STATE_DOWNLOADING);

        /* When switching to the operational firmware the device
         * sends a vendor specific event indicating that the bootup
         * completed.
         */
        } else if (skb->len == 9 && hdr->evt == 0xff && hdr->plen == 0x07 &&
                   skb->data[2] == 0x02) {
                if (test_and_clear_bit(STATE_BOOTING, &intel->flags))
                        wake_up_bit(&intel->flags, STATE_BOOTING);
        }
recv:
        return hci_recv_frame(hdev, skb);
}

static void intel_recv_lpm_notify(struct hci_dev *hdev, int value)
{
        struct hci_uart *hu = hci_get_drvdata(hdev);
        struct intel_data *intel = hu->priv;

        bt_dev_dbg(hdev, "TX idle notification (%d)", value);

        if (value) {
                set_bit(STATE_TX_ACTIVE, &intel->flags);
                schedule_work(&intel->busy_work);
        } else {
                clear_bit(STATE_TX_ACTIVE, &intel->flags);
        }
}

static int intel_recv_lpm(struct hci_dev *hdev, struct sk_buff *skb)
{
        struct hci_lpm_pkt *lpm = (void *)skb->data;
        struct hci_uart *hu = hci_get_drvdata(hdev);
        struct intel_data *intel = hu->priv;

        switch (lpm->opcode) {
        case LPM_OP_TX_NOTIFY:
                if (lpm->dlen < 1) {
                        bt_dev_err(hu->hdev, "Invalid LPM notification packet");
                        break;
                }
                intel_recv_lpm_notify(hdev, lpm->data[0]);
                break;
        case LPM_OP_SUSPEND_ACK:
                set_bit(STATE_SUSPENDED, &intel->flags);
                if (test_and_clear_bit(STATE_LPM_TRANSACTION, &intel->flags))
                        wake_up_bit(&intel->flags, STATE_LPM_TRANSACTION);
                break;
        case LPM_OP_RESUME_ACK:
                clear_bit(STATE_SUSPENDED, &intel->flags);
                if (test_and_clear_bit(STATE_LPM_TRANSACTION, &intel->flags))
                        wake_up_bit(&intel->flags, STATE_LPM_TRANSACTION);
                break;
        default:
                bt_dev_err(hdev, "Unknown LPM opcode (%02x)", lpm->opcode);
                break;
        }

        kfree_skb(skb);

        return 0;
}

#define INTEL_RECV_LPM \
        .type = HCI_LPM_PKT, \
        .hlen = HCI_LPM_HDR_SIZE, \
        .loff = 1, \
        .lsize = 1, \
        .maxlen = HCI_LPM_MAX_SIZE

static const struct h4_recv_pkt intel_recv_pkts[] = {
        { H4_RECV_ACL,    .recv = hci_recv_frame   },
        { H4_RECV_SCO,    .recv = hci_recv_frame   },
        { H4_RECV_EVENT,  .recv = intel_recv_event },
        { INTEL_RECV_LPM, .recv = intel_recv_lpm   },
};

static int intel_recv(struct hci_uart *hu, const void *data, int count)
{
        struct intel_data *intel = hu->priv;

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

        intel->rx_skb = h4_recv_buf(hu, intel->rx_skb, data, count,
                                    intel_recv_pkts,
                                    ARRAY_SIZE(intel_recv_pkts));
        if (IS_ERR(intel->rx_skb)) {
                int err = PTR_ERR(intel->rx_skb);

                bt_dev_err(hu->hdev, "Frame reassembly failed (%d)", err);
                intel->rx_skb = NULL;
                return err;
        }

        return count;
}

static int intel_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
        struct intel_data *intel = hu->priv;
        struct intel_device *idev;

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

        if (!hu->tty->dev)
                goto out_enqueue;

        /* Be sure our controller is resumed and potential LPM transaction
         * completed before enqueuing any packet.
         */
        mutex_lock(&intel_device_list_lock);
        list_for_each_entry(idev, &intel_device_list, list) {
                if (hu->tty->dev->parent == idev->pdev->dev.parent) {
                        pm_runtime_get_sync(&idev->pdev->dev);
                        pm_runtime_put_autosuspend(&idev->pdev->dev);
                        break;
                }
        }
        mutex_unlock(&intel_device_list_lock);
out_enqueue:
        skb_queue_tail(&intel->txq, skb);

        return 0;
}

static struct sk_buff *intel_dequeue(struct hci_uart *hu)
{
        struct intel_data *intel = hu->priv;
        struct sk_buff *skb;

        skb = skb_dequeue(&intel->txq);
        if (!skb)
                return skb;

        if (test_bit(STATE_BOOTLOADER, &intel->flags) &&
            (hci_skb_pkt_type(skb) == HCI_COMMAND_PKT)) {
                struct hci_command_hdr *cmd = (void *)skb->data;
                __u16 opcode = le16_to_cpu(cmd->opcode);

                /* When the BTINTEL_HCI_OP_RESET command is issued to boot into
                 * the operational firmware, it will actually not send a command
                 * complete event. To keep the flow control working inject that
                 * event here.
                 */
                if (opcode == BTINTEL_HCI_OP_RESET)
                        inject_cmd_complete(hu->hdev, opcode);
        }

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

        return skb;
}

static const struct hci_uart_proto intel_proto = {
        .id             = HCI_UART_INTEL,
        .name           = "Intel",
        .manufacturer   = 2,
        .init_speed     = 115200,
        .oper_speed     = 3000000,
        .open           = intel_open,
        .close          = intel_close,
        .flush          = intel_flush,
        .setup          = intel_setup,
        .set_baudrate   = intel_set_baudrate,
        .recv           = intel_recv,
        .enqueue        = intel_enqueue,
        .dequeue        = intel_dequeue,
};

#ifdef CONFIG_ACPI
static const struct acpi_device_id intel_acpi_match[] = {
        { "INT33E1", 0 },
        { "INT33E3", 0 },
        { }
};
MODULE_DEVICE_TABLE(acpi, intel_acpi_match);
#endif

static int intel_suspend_device(struct device *dev)
{
        struct intel_device *idev = dev_get_drvdata(dev);

        mutex_lock(&idev->hu_lock);
        if (idev->hu)
                intel_lpm_suspend(idev->hu);
        mutex_unlock(&idev->hu_lock);

        return 0;
}

static int intel_resume_device(struct device *dev)
{
        struct intel_device *idev = dev_get_drvdata(dev);

        mutex_lock(&idev->hu_lock);
        if (idev->hu)
                intel_lpm_resume(idev->hu);
        mutex_unlock(&idev->hu_lock);

        return 0;
}

static int __maybe_unused intel_suspend(struct device *dev)
{
        struct intel_device *idev = dev_get_drvdata(dev);

        if (device_may_wakeup(dev))
                enable_irq_wake(idev->irq);

        return intel_suspend_device(dev);
}

static int __maybe_unused intel_resume(struct device *dev)
{
        struct intel_device *idev = dev_get_drvdata(dev);

        if (device_may_wakeup(dev))
                disable_irq_wake(idev->irq);

        return intel_resume_device(dev);
}

static const struct dev_pm_ops intel_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(intel_suspend, intel_resume)
        SET_RUNTIME_PM_OPS(intel_suspend_device, intel_resume_device, NULL)
};

static const struct acpi_gpio_params reset_gpios = { 0, 0, false };
static const struct acpi_gpio_params host_wake_gpios = { 1, 0, false };

static const struct acpi_gpio_mapping acpi_hci_intel_gpios[] = {
        { "reset-gpios", &reset_gpios, 1, ACPI_GPIO_QUIRK_ONLY_GPIOIO },
        { "host-wake-gpios", &host_wake_gpios, 1, ACPI_GPIO_QUIRK_ONLY_GPIOIO },
        { }
};

static int intel_probe(struct platform_device *pdev)
{
        struct intel_device *idev;
        int ret;

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

        mutex_init(&idev->hu_lock);

        idev->pdev = pdev;

        ret = devm_acpi_dev_add_driver_gpios(&pdev->dev, acpi_hci_intel_gpios);
        if (ret)
                dev_dbg(&pdev->dev, "Unable to add GPIO mapping table\n");

        idev->reset = devm_gpiod_get(&pdev->dev, "reset", GPIOD_OUT_LOW);
        if (IS_ERR(idev->reset)) {
                dev_err(&pdev->dev, "Unable to retrieve gpio\n");
                return PTR_ERR(idev->reset);
        }

        idev->irq = platform_get_irq(pdev, 0);
        if (idev->irq < 0) {
                struct gpio_desc *host_wake;

                dev_err(&pdev->dev, "No IRQ, falling back to gpio-irq\n");

                host_wake = devm_gpiod_get(&pdev->dev, "host-wake", GPIOD_IN);
                if (IS_ERR(host_wake)) {
                        dev_err(&pdev->dev, "Unable to retrieve IRQ\n");
                        goto no_irq;
                }

                idev->irq = gpiod_to_irq(host_wake);
                if (idev->irq < 0) {
                        dev_err(&pdev->dev, "No corresponding irq for gpio\n");
                        goto no_irq;
                }
        }

        /* Only enable wake-up/irq when controller is powered */
        device_set_wakeup_capable(&pdev->dev, true);
        device_wakeup_disable(&pdev->dev);

no_irq:
        platform_set_drvdata(pdev, idev);

        /* Place this instance on the device list */
        mutex_lock(&intel_device_list_lock);
        list_add_tail(&idev->list, &intel_device_list);
        mutex_unlock(&intel_device_list_lock);

        dev_info(&pdev->dev, "registered, gpio(%d)/irq(%d).\n",
                 desc_to_gpio(idev->reset), idev->irq);

        return 0;
}

static void intel_remove(struct platform_device *pdev)
{
        struct intel_device *idev = platform_get_drvdata(pdev);

        device_wakeup_disable(&pdev->dev);

        mutex_lock(&intel_device_list_lock);
        list_del(&idev->list);
        mutex_unlock(&intel_device_list_lock);

        dev_info(&pdev->dev, "unregistered.\n");
}

static struct platform_driver intel_driver = {
        .probe = intel_probe,
        .remove = intel_remove,
        .driver = {
                .name = "hci_intel",
                .acpi_match_table = ACPI_PTR(intel_acpi_match),
                .pm = &intel_pm_ops,
        },
};

int __init intel_init(void)
{
        int err;

        err = platform_driver_register(&intel_driver);
        if (err)
                return err;

        return hci_uart_register_proto(&intel_proto);
}

int __exit intel_deinit(void)
{
        platform_driver_unregister(&intel_driver);

        return hci_uart_unregister_proto(&intel_proto);
}