/*
 *
 *  Bluetooth HCI UART driver for Broadcom devices
 *
 *  Copyright (C) 2015  Intel Corporation
 *
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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/errno.h>
#include <linux/skbuff.h>
#include <linux/firmware.h>
#include <linux/module.h>
#include <linux/acpi.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/gpio/consumer.h>
#include <linux/tty.h>

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

#include "btbcm.h"
#include "hci_uart.h"

struct bcm_device {
	struct list_head	list;

	struct platform_device	*pdev;

	const char		*name;
	struct gpio_desc	*device_wakeup;
	struct gpio_desc	*shutdown;

	struct clk		*clk;
	bool			clk_enabled;

	u32			init_speed;

#ifdef CONFIG_PM_SLEEP
	struct hci_uart		*hu;
	bool			is_suspended; /* suspend/resume flag */
#endif
};

struct bcm_data {
	struct sk_buff		*rx_skb;
	struct sk_buff_head	txq;

	struct bcm_device	*dev;
};

/* List of BCM BT UART devices */
static DEFINE_SPINLOCK(bcm_device_list_lock);
static LIST_HEAD(bcm_device_list);

static int bcm_set_baudrate(struct hci_uart *hu, unsigned int speed)
{
	struct hci_dev *hdev = hu->hdev;
	struct sk_buff *skb;
	struct bcm_update_uart_baud_rate param;

	if (speed > 3000000) {
		struct bcm_write_uart_clock_setting clock;

		clock.type = BCM_UART_CLOCK_48MHZ;

		BT_DBG("%s: Set Controller clock (%d)", hdev->name, clock.type);

		/* This Broadcom specific command changes the UART's controller
		 * clock for baud rate > 3000000.
		 */
		skb = __hci_cmd_sync(hdev, 0xfc45, 1, &clock, HCI_INIT_TIMEOUT);
		if (IS_ERR(skb)) {
			int err = PTR_ERR(skb);
			BT_ERR("%s: BCM: failed to write clock command (%d)",
			       hdev->name, err);
			return err;
		}

		kfree_skb(skb);
	}

	BT_DBG("%s: Set Controller UART speed to %d bit/s", hdev->name, speed);

	param.zero = cpu_to_le16(0);
	param.baud_rate = cpu_to_le32(speed);

	/* This Broadcom specific command changes the UART's controller baud
	 * rate.
	 */
	skb = __hci_cmd_sync(hdev, 0xfc18, sizeof(param), &param,
			     HCI_INIT_TIMEOUT);
	if (IS_ERR(skb)) {
		int err = PTR_ERR(skb);
		BT_ERR("%s: BCM: failed to write update baudrate command (%d)",
		       hdev->name, err);
		return err;
	}

	kfree_skb(skb);

	return 0;
}

/* bcm_device_exists should be protected by bcm_device_list_lock */
static bool bcm_device_exists(struct bcm_device *device)
{
	struct list_head *p;

	list_for_each(p, &bcm_device_list) {
		struct bcm_device *dev = list_entry(p, struct bcm_device, list);

		if (device == dev)
			return true;
	}

	return false;
}

static int bcm_gpio_set_power(struct bcm_device *dev, bool powered)
{
	if (powered && !IS_ERR(dev->clk) && !dev->clk_enabled)
		clk_enable(dev->clk);

	gpiod_set_value_cansleep(dev->shutdown, powered);
	gpiod_set_value_cansleep(dev->device_wakeup, powered);

	if (!powered && !IS_ERR(dev->clk) && dev->clk_enabled)
		clk_disable(dev->clk);

	dev->clk_enabled = powered;

	return 0;
}

static int bcm_open(struct hci_uart *hu)
{
	struct bcm_data *bcm;
	struct list_head *p;

	BT_DBG("hu %p", hu);

	bcm = kzalloc(sizeof(*bcm), GFP_KERNEL);
	if (!bcm)
		return -ENOMEM;

	skb_queue_head_init(&bcm->txq);

	hu->priv = bcm;

	spin_lock(&bcm_device_list_lock);
	list_for_each(p, &bcm_device_list) {
		struct bcm_device *dev = list_entry(p, struct bcm_device, list);

		/* Retrieve saved bcm_device based on parent of the
		 * platform device (saved during device probe) and
		 * parent of tty device used by hci_uart
		 */
		if (hu->tty->dev->parent == dev->pdev->dev.parent) {
			bcm->dev = dev;
			hu->init_speed = dev->init_speed;
#ifdef CONFIG_PM_SLEEP
			dev->hu = hu;
#endif
			break;
		}
	}

	if (bcm->dev)
		bcm_gpio_set_power(bcm->dev, true);

	spin_unlock(&bcm_device_list_lock);

	return 0;
}

static int bcm_close(struct hci_uart *hu)
{
	struct bcm_data *bcm = hu->priv;

	BT_DBG("hu %p", hu);

	/* Protect bcm->dev against removal of the device or driver */
	spin_lock(&bcm_device_list_lock);
	if (bcm_device_exists(bcm->dev)) {
		bcm_gpio_set_power(bcm->dev, false);
#ifdef CONFIG_PM_SLEEP
		bcm->dev->hu = NULL;
#endif
	}
	spin_unlock(&bcm_device_list_lock);

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

	hu->priv = NULL;
	return 0;
}

static int bcm_flush(struct hci_uart *hu)
{
	struct bcm_data *bcm = hu->priv;

	BT_DBG("hu %p", hu);

	skb_queue_purge(&bcm->txq);

	return 0;
}

static int bcm_setup(struct hci_uart *hu)
{
	char fw_name[64];
	const struct firmware *fw;
	unsigned int speed;
	int err;

	BT_DBG("hu %p", hu);

	hu->hdev->set_bdaddr = btbcm_set_bdaddr;

	err = btbcm_initialize(hu->hdev, fw_name, sizeof(fw_name));
	if (err)
		return err;

	err = request_firmware(&fw, fw_name, &hu->hdev->dev);
	if (err < 0) {
		BT_INFO("%s: BCM: Patch %s not found", hu->hdev->name, fw_name);
		return 0;
	}

	err = btbcm_patchram(hu->hdev, fw);
	if (err) {
		BT_INFO("%s: BCM: Patch failed (%d)", hu->hdev->name, err);
		goto finalize;
	}

	/* Init speed if any */
	if (hu->init_speed)
		speed = hu->init_speed;
	else if (hu->proto->init_speed)
		speed = hu->proto->init_speed;
	else
		speed = 0;

	if (speed)
		hci_uart_set_baudrate(hu, speed);

	/* Operational speed if any */
	if (hu->oper_speed)
		speed = hu->oper_speed;
	else if (hu->proto->oper_speed)
		speed = hu->proto->oper_speed;
	else
		speed = 0;

	if (speed) {
		err = bcm_set_baudrate(hu, speed);
		if (!err)
			hci_uart_set_baudrate(hu, speed);
	}

finalize:
	release_firmware(fw);

	err = btbcm_finalize(hu->hdev);

	return err;
}

static const struct h4_recv_pkt bcm_recv_pkts[] = {
	{ H4_RECV_ACL,   .recv = hci_recv_frame },
	{ H4_RECV_SCO,   .recv = hci_recv_frame },
	{ H4_RECV_EVENT, .recv = hci_recv_frame },
};

static int bcm_recv(struct hci_uart *hu, const void *data, int count)
{
	struct bcm_data *bcm = hu->priv;

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

	bcm->rx_skb = h4_recv_buf(hu->hdev, bcm->rx_skb, data, count,
				  bcm_recv_pkts, ARRAY_SIZE(bcm_recv_pkts));
	if (IS_ERR(bcm->rx_skb)) {
		int err = PTR_ERR(bcm->rx_skb);
		BT_ERR("%s: Frame reassembly failed (%d)", hu->hdev->name, err);
		bcm->rx_skb = NULL;
		return err;
	}

	return count;
}

static int bcm_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
	struct bcm_data *bcm = 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);
	skb_queue_tail(&bcm->txq, skb);

	return 0;
}

static struct sk_buff *bcm_dequeue(struct hci_uart *hu)
{
	struct bcm_data *bcm = hu->priv;

	return skb_dequeue(&bcm->txq);
}

#ifdef CONFIG_PM_SLEEP
/* Platform suspend callback */
static int bcm_suspend(struct device *dev)
{
	struct bcm_device *bdev = platform_get_drvdata(to_platform_device(dev));

	BT_DBG("suspend (%p): is_suspended %d", bdev, bdev->is_suspended);

	if (!bdev->is_suspended) {
		hci_uart_set_flow_control(bdev->hu, true);

		/* Once this callback returns, driver suspends BT via GPIO */
		bdev->is_suspended = true;
	}

	/* Suspend the device */
	if (bdev->device_wakeup) {
		gpiod_set_value(bdev->device_wakeup, false);
		BT_DBG("suspend, delaying 15 ms");
		mdelay(15);
	}

	return 0;
}

/* Platform resume callback */
static int bcm_resume(struct device *dev)
{
	struct bcm_device *bdev = platform_get_drvdata(to_platform_device(dev));

	BT_DBG("resume (%p): is_suspended %d", bdev, bdev->is_suspended);

	if (bdev->device_wakeup) {
		gpiod_set_value(bdev->device_wakeup, true);
		BT_DBG("resume, delaying 15 ms");
		mdelay(15);
	}

	/* When this callback executes, the device has woken up already */
	if (bdev->is_suspended) {
		bdev->is_suspended = false;

		hci_uart_set_flow_control(bdev->hu, false);
	}

	return 0;
}
#endif

static const struct acpi_gpio_params device_wakeup_gpios = { 0, 0, false };
static const struct acpi_gpio_params shutdown_gpios = { 1, 0, false };

static const struct acpi_gpio_mapping acpi_bcm_default_gpios[] = {
	{ "device-wakeup-gpios", &device_wakeup_gpios, 1 },
	{ "shutdown-gpios", &shutdown_gpios, 1 },
	{ },
};

#ifdef CONFIG_ACPI
static int bcm_resource(struct acpi_resource *ares, void *data)
{
	struct bcm_device *dev = data;

	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
		struct acpi_resource_uart_serialbus *sb;

		sb = &ares->data.uart_serial_bus;
		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_UART)
			dev->init_speed = sb->default_baud_rate;
	}

	/* Always tell the ACPI core to skip this resource */
	return 1;
}

static int bcm_acpi_probe(struct bcm_device *dev)
{
	struct platform_device *pdev = dev->pdev;
	const struct acpi_device_id *id;
	struct acpi_device *adev;
	LIST_HEAD(resources);
	int ret;

	id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
	if (!id)
		return -ENODEV;

	/* Retrieve GPIO data */
	dev->name = dev_name(&pdev->dev);
	ret = acpi_dev_add_driver_gpios(ACPI_COMPANION(&pdev->dev),
					acpi_bcm_default_gpios);
	if (ret)
		return ret;

	dev->clk = devm_clk_get(&pdev->dev, NULL);

	dev->device_wakeup = devm_gpiod_get_optional(&pdev->dev,
						     "device-wakeup",
						     GPIOD_OUT_LOW);
	if (IS_ERR(dev->device_wakeup))
		return PTR_ERR(dev->device_wakeup);

	dev->shutdown = devm_gpiod_get_optional(&pdev->dev, "shutdown",
						GPIOD_OUT_LOW);
	if (IS_ERR(dev->shutdown))
		return PTR_ERR(dev->shutdown);

	/* Make sure at-least one of the GPIO is defined and that
	 * a name is specified for this instance
	 */
	if ((!dev->device_wakeup && !dev->shutdown) || !dev->name) {
		dev_err(&pdev->dev, "invalid platform data\n");
		return -EINVAL;
	}

	/* Retrieve UART ACPI info */
	adev = ACPI_COMPANION(&dev->pdev->dev);
	if (!adev)
		return 0;

	acpi_dev_get_resources(adev, &resources, bcm_resource, dev);

	return 0;
}
#else
static int bcm_acpi_probe(struct bcm_device *dev)
{
	return -EINVAL;
}
#endif /* CONFIG_ACPI */

static int bcm_probe(struct platform_device *pdev)
{
	struct bcm_device *dev;
	struct acpi_device_id *pdata = pdev->dev.platform_data;
	int ret;

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

	dev->pdev = pdev;

	if (ACPI_HANDLE(&pdev->dev)) {
		ret = bcm_acpi_probe(dev);
		if (ret)
			return ret;
	} else if (pdata) {
		dev->name = pdata->id;
	} else {
		return -ENODEV;
	}

	platform_set_drvdata(pdev, dev);

	dev_info(&pdev->dev, "%s device registered.\n", dev->name);

	/* Place this instance on the device list */
	spin_lock(&bcm_device_list_lock);
	list_add_tail(&dev->list, &bcm_device_list);
	spin_unlock(&bcm_device_list_lock);

	bcm_gpio_set_power(dev, false);

	return 0;
}

static int bcm_remove(struct platform_device *pdev)
{
	struct bcm_device *dev = platform_get_drvdata(pdev);

	spin_lock(&bcm_device_list_lock);
	list_del(&dev->list);
	spin_unlock(&bcm_device_list_lock);

	acpi_dev_remove_driver_gpios(ACPI_COMPANION(&pdev->dev));

	dev_info(&pdev->dev, "%s device unregistered.\n", dev->name);

	return 0;
}

static const struct hci_uart_proto bcm_proto = {
	.id		= HCI_UART_BCM,
	.name		= "BCM",
	.init_speed	= 115200,
	.oper_speed	= 4000000,
	.open		= bcm_open,
	.close		= bcm_close,
	.flush		= bcm_flush,
	.setup		= bcm_setup,
	.set_baudrate	= bcm_set_baudrate,
	.recv		= bcm_recv,
	.enqueue	= bcm_enqueue,
	.dequeue	= bcm_dequeue,
};

#ifdef CONFIG_ACPI
static const struct acpi_device_id bcm_acpi_match[] = {
	{ "BCM2E39", 0 },
	{ "BCM2E67", 0 },
	{ },
};
MODULE_DEVICE_TABLE(acpi, bcm_acpi_match);
#endif

/* Platform suspend and resume callbacks */
static SIMPLE_DEV_PM_OPS(bcm_pm_ops, bcm_suspend, bcm_resume);

static struct platform_driver bcm_driver = {
	.probe = bcm_probe,
	.remove = bcm_remove,
	.driver = {
		.name = "hci_bcm",
		.acpi_match_table = ACPI_PTR(bcm_acpi_match),
		.pm = &bcm_pm_ops,
	},
};

int __init bcm_init(void)
{
	platform_driver_register(&bcm_driver);

	return hci_uart_register_proto(&bcm_proto);
}

int __exit bcm_deinit(void)
{
	platform_driver_unregister(&bcm_driver);

	return hci_uart_unregister_proto(&bcm_proto);
}