/*
 *
 *  Driver for Bluetooth PCMCIA cards with HCI UART interface
 *
 *  Copyright (C) 2001-2002  Marcel Holtmann <marcel@holtmann.org>
 *
 *
 *  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;
 *
 *  Software distributed under the License is distributed on an "AS
 *  IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 *  implied. See the License for the specific language governing
 *  rights and limitations under the License.
 *
 *  The initial developer of the original code is David A. Hinds
 *  <dahinds@users.sourceforge.net>.  Portions created by David A. Hinds
 *  are Copyright (C) 1999 David A. Hinds.  All Rights Reserved.
 *
 */

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/spinlock.h>
#include <linux/moduleparam.h>

#include <linux/skbuff.h>
#include <linux/string.h>
#include <linux/serial.h>
#include <linux/serial_reg.h>
#include <linux/bitops.h>
#include <linux/io.h>

#include <pcmcia/cistpl.h>
#include <pcmcia/ciscode.h>
#include <pcmcia/ds.h>
#include <pcmcia/cisreg.h>

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


/* ======================== Module parameters ======================== */


MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
MODULE_DESCRIPTION("Bluetooth driver for Bluetooth PCMCIA cards with HCI UART interface");
MODULE_LICENSE("GPL");


/* ======================== Local structures ======================== */


struct btuart_info {
	struct pcmcia_device *p_dev;

	struct hci_dev *hdev;

	spinlock_t lock;	/* For serializing operations */

	struct sk_buff_head txq;
	unsigned long tx_state;

	unsigned long rx_state;
	unsigned long rx_count;
	struct sk_buff *rx_skb;
};


static int btuart_config(struct pcmcia_device *link);
static void btuart_release(struct pcmcia_device *link);

static void btuart_detach(struct pcmcia_device *p_dev);


/* Maximum baud rate */
#define SPEED_MAX  115200

/* Default baud rate: 57600, 115200, 230400 or 460800 */
#define DEFAULT_BAUD_RATE  115200


/* Transmit states  */
#define XMIT_SENDING	1
#define XMIT_WAKEUP	2
#define XMIT_WAITING	8

/* Receiver states */
#define RECV_WAIT_PACKET_TYPE	0
#define RECV_WAIT_EVENT_HEADER	1
#define RECV_WAIT_ACL_HEADER	2
#define RECV_WAIT_SCO_HEADER	3
#define RECV_WAIT_DATA		4


/* ======================== Interrupt handling ======================== */


static int btuart_write(unsigned int iobase, int fifo_size, __u8 *buf, int len)
{
	int actual = 0;

	/* Tx FIFO should be empty */
	if (!(inb(iobase + UART_LSR) & UART_LSR_THRE))
		return 0;

	/* Fill FIFO with current frame */
	while ((fifo_size-- > 0) && (actual < len)) {
		/* Transmit next byte */
		outb(buf[actual], iobase + UART_TX);
		actual++;
	}

	return actual;
}


static void btuart_write_wakeup(struct btuart_info *info)
{
	if (!info) {
		BT_ERR("Unknown device");
		return;
	}

	if (test_and_set_bit(XMIT_SENDING, &(info->tx_state))) {
		set_bit(XMIT_WAKEUP, &(info->tx_state));
		return;
	}

	do {
		unsigned int iobase = info->p_dev->resource[0]->start;
		register struct sk_buff *skb;
		int len;

		clear_bit(XMIT_WAKEUP, &(info->tx_state));

		if (!pcmcia_dev_present(info->p_dev))
			return;

		skb = skb_dequeue(&(info->txq));
		if (!skb)
			break;

		/* Send frame */
		len = btuart_write(iobase, 16, skb->data, skb->len);
		set_bit(XMIT_WAKEUP, &(info->tx_state));

		if (len == skb->len) {
			kfree_skb(skb);
		} else {
			skb_pull(skb, len);
			skb_queue_head(&(info->txq), skb);
		}

		info->hdev->stat.byte_tx += len;

	} while (test_bit(XMIT_WAKEUP, &(info->tx_state)));

	clear_bit(XMIT_SENDING, &(info->tx_state));
}


static void btuart_receive(struct btuart_info *info)
{
	unsigned int iobase;
	int boguscount = 0;

	if (!info) {
		BT_ERR("Unknown device");
		return;
	}

	iobase = info->p_dev->resource[0]->start;

	do {
		info->hdev->stat.byte_rx++;

		/* Allocate packet */
		if (!info->rx_skb) {
			info->rx_state = RECV_WAIT_PACKET_TYPE;
			info->rx_count = 0;
			info->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);
			if (!info->rx_skb) {
				BT_ERR("Can't allocate mem for new packet");
				return;
			}
		}

		if (info->rx_state == RECV_WAIT_PACKET_TYPE) {

			bt_cb(info->rx_skb)->pkt_type = inb(iobase + UART_RX);

			switch (bt_cb(info->rx_skb)->pkt_type) {

			case HCI_EVENT_PKT:
				info->rx_state = RECV_WAIT_EVENT_HEADER;
				info->rx_count = HCI_EVENT_HDR_SIZE;
				break;

			case HCI_ACLDATA_PKT:
				info->rx_state = RECV_WAIT_ACL_HEADER;
				info->rx_count = HCI_ACL_HDR_SIZE;
				break;

			case HCI_SCODATA_PKT:
				info->rx_state = RECV_WAIT_SCO_HEADER;
				info->rx_count = HCI_SCO_HDR_SIZE;
				break;

			default:
				/* Unknown packet */
				BT_ERR("Unknown HCI packet with type 0x%02x received", bt_cb(info->rx_skb)->pkt_type);
				info->hdev->stat.err_rx++;

				kfree_skb(info->rx_skb);
				info->rx_skb = NULL;
				break;

			}

		} else {

			*skb_put(info->rx_skb, 1) = inb(iobase + UART_RX);
			info->rx_count--;

			if (info->rx_count == 0) {

				int dlen;
				struct hci_event_hdr *eh;
				struct hci_acl_hdr *ah;
				struct hci_sco_hdr *sh;


				switch (info->rx_state) {

				case RECV_WAIT_EVENT_HEADER:
					eh = hci_event_hdr(info->rx_skb);
					info->rx_state = RECV_WAIT_DATA;
					info->rx_count = eh->plen;
					break;

				case RECV_WAIT_ACL_HEADER:
					ah = hci_acl_hdr(info->rx_skb);
					dlen = __le16_to_cpu(ah->dlen);
					info->rx_state = RECV_WAIT_DATA;
					info->rx_count = dlen;
					break;

				case RECV_WAIT_SCO_HEADER:
					sh = hci_sco_hdr(info->rx_skb);
					info->rx_state = RECV_WAIT_DATA;
					info->rx_count = sh->dlen;
					break;

				case RECV_WAIT_DATA:
					hci_recv_frame(info->hdev, info->rx_skb);
					info->rx_skb = NULL;
					break;

				}

			}

		}

		/* Make sure we don't stay here too long */
		if (boguscount++ > 16)
			break;

	} while (inb(iobase + UART_LSR) & UART_LSR_DR);
}


static irqreturn_t btuart_interrupt(int irq, void *dev_inst)
{
	struct btuart_info *info = dev_inst;
	unsigned int iobase;
	int boguscount = 0;
	int iir, lsr;
	irqreturn_t r = IRQ_NONE;

	if (!info || !info->hdev)
		/* our irq handler is shared */
		return IRQ_NONE;

	iobase = info->p_dev->resource[0]->start;

	spin_lock(&(info->lock));

	iir = inb(iobase + UART_IIR) & UART_IIR_ID;
	while (iir) {
		r = IRQ_HANDLED;

		/* Clear interrupt */
		lsr = inb(iobase + UART_LSR);

		switch (iir) {
		case UART_IIR_RLSI:
			BT_ERR("RLSI");
			break;
		case UART_IIR_RDI:
			/* Receive interrupt */
			btuart_receive(info);
			break;
		case UART_IIR_THRI:
			if (lsr & UART_LSR_THRE) {
				/* Transmitter ready for data */
				btuart_write_wakeup(info);
			}
			break;
		default:
			BT_ERR("Unhandled IIR=%#x", iir);
			break;
		}

		/* Make sure we don't stay here too long */
		if (boguscount++ > 100)
			break;

		iir = inb(iobase + UART_IIR) & UART_IIR_ID;

	}

	spin_unlock(&(info->lock));

	return r;
}


static void btuart_change_speed(struct btuart_info *info,
				unsigned int speed)
{
	unsigned long flags;
	unsigned int iobase;
	int fcr;		/* FIFO control reg */
	int lcr;		/* Line control reg */
	int divisor;

	if (!info) {
		BT_ERR("Unknown device");
		return;
	}

	iobase = info->p_dev->resource[0]->start;

	spin_lock_irqsave(&(info->lock), flags);

	/* Turn off interrupts */
	outb(0, iobase + UART_IER);

	divisor = SPEED_MAX / speed;

	fcr = UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT;

	/* 
	 * Use trigger level 1 to avoid 3 ms. timeout delay at 9600 bps, and
	 * almost 1,7 ms at 19200 bps. At speeds above that we can just forget
	 * about this timeout since it will always be fast enough. 
	 */

	if (speed < 38400)
		fcr |= UART_FCR_TRIGGER_1;
	else
		fcr |= UART_FCR_TRIGGER_14;

	/* Bluetooth cards use 8N1 */
	lcr = UART_LCR_WLEN8;

	outb(UART_LCR_DLAB | lcr, iobase + UART_LCR);	/* Set DLAB */
	outb(divisor & 0xff, iobase + UART_DLL);	/* Set speed */
	outb(divisor >> 8, iobase + UART_DLM);
	outb(lcr, iobase + UART_LCR);	/* Set 8N1  */
	outb(fcr, iobase + UART_FCR);	/* Enable FIFO's */

	/* Turn on interrupts */
	outb(UART_IER_RLSI | UART_IER_RDI | UART_IER_THRI, iobase + UART_IER);

	spin_unlock_irqrestore(&(info->lock), flags);
}


/* ======================== HCI interface ======================== */


static int btuart_hci_flush(struct hci_dev *hdev)
{
	struct btuart_info *info = hci_get_drvdata(hdev);

	/* Drop TX queue */
	skb_queue_purge(&(info->txq));

	return 0;
}


static int btuart_hci_open(struct hci_dev *hdev)
{
	return 0;
}


static int btuart_hci_close(struct hci_dev *hdev)
{
	btuart_hci_flush(hdev);

	return 0;
}


static int btuart_hci_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
{
	struct btuart_info *info = hci_get_drvdata(hdev);

	switch (bt_cb(skb)->pkt_type) {
	case HCI_COMMAND_PKT:
		hdev->stat.cmd_tx++;
		break;
	case HCI_ACLDATA_PKT:
		hdev->stat.acl_tx++;
		break;
	case HCI_SCODATA_PKT:
		hdev->stat.sco_tx++;
		break;
	}

	/* Prepend skb with frame type */
	memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
	skb_queue_tail(&(info->txq), skb);

	btuart_write_wakeup(info);

	return 0;
}


/* ======================== Card services HCI interaction ======================== */


static int btuart_open(struct btuart_info *info)
{
	unsigned long flags;
	unsigned int iobase = info->p_dev->resource[0]->start;
	struct hci_dev *hdev;

	spin_lock_init(&(info->lock));

	skb_queue_head_init(&(info->txq));

	info->rx_state = RECV_WAIT_PACKET_TYPE;
	info->rx_count = 0;
	info->rx_skb = NULL;

	/* Initialize HCI device */
	hdev = hci_alloc_dev();
	if (!hdev) {
		BT_ERR("Can't allocate HCI device");
		return -ENOMEM;
	}

	info->hdev = hdev;

	hdev->bus = HCI_PCCARD;
	hci_set_drvdata(hdev, info);
	SET_HCIDEV_DEV(hdev, &info->p_dev->dev);

	hdev->open  = btuart_hci_open;
	hdev->close = btuart_hci_close;
	hdev->flush = btuart_hci_flush;
	hdev->send  = btuart_hci_send_frame;

	spin_lock_irqsave(&(info->lock), flags);

	/* Reset UART */
	outb(0, iobase + UART_MCR);

	/* Turn off interrupts */
	outb(0, iobase + UART_IER);

	/* Initialize UART */
	outb(UART_LCR_WLEN8, iobase + UART_LCR);	/* Reset DLAB */
	outb((UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2), iobase + UART_MCR);

	/* Turn on interrupts */
	// outb(UART_IER_RLSI | UART_IER_RDI | UART_IER_THRI, iobase + UART_IER);

	spin_unlock_irqrestore(&(info->lock), flags);

	btuart_change_speed(info, DEFAULT_BAUD_RATE);

	/* Timeout before it is safe to send the first HCI packet */
	msleep(1000);

	/* Register HCI device */
	if (hci_register_dev(hdev) < 0) {
		BT_ERR("Can't register HCI device");
		info->hdev = NULL;
		hci_free_dev(hdev);
		return -ENODEV;
	}

	return 0;
}


static int btuart_close(struct btuart_info *info)
{
	unsigned long flags;
	unsigned int iobase = info->p_dev->resource[0]->start;
	struct hci_dev *hdev = info->hdev;

	if (!hdev)
		return -ENODEV;

	btuart_hci_close(hdev);

	spin_lock_irqsave(&(info->lock), flags);

	/* Reset UART */
	outb(0, iobase + UART_MCR);

	/* Turn off interrupts */
	outb(0, iobase + UART_IER);

	spin_unlock_irqrestore(&(info->lock), flags);

	hci_unregister_dev(hdev);
	hci_free_dev(hdev);

	return 0;
}

static int btuart_probe(struct pcmcia_device *link)
{
	struct btuart_info *info;

	/* Create new info device */
	info = devm_kzalloc(&link->dev, sizeof(*info), GFP_KERNEL);
	if (!info)
		return -ENOMEM;

	info->p_dev = link;
	link->priv = info;

	link->config_flags |= CONF_ENABLE_IRQ | CONF_AUTO_SET_VPP |
		CONF_AUTO_SET_IO;

	return btuart_config(link);
}


static void btuart_detach(struct pcmcia_device *link)
{
	btuart_release(link);
}

static int btuart_check_config(struct pcmcia_device *p_dev, void *priv_data)
{
	int *try = priv_data;

	if (!try)
		p_dev->io_lines = 16;

	if ((p_dev->resource[0]->end != 8) || (p_dev->resource[0]->start == 0))
		return -EINVAL;

	p_dev->resource[0]->end = 8;
	p_dev->resource[0]->flags &= ~IO_DATA_PATH_WIDTH;
	p_dev->resource[0]->flags |= IO_DATA_PATH_WIDTH_8;

	return pcmcia_request_io(p_dev);
}

static int btuart_check_config_notpicky(struct pcmcia_device *p_dev,
					void *priv_data)
{
	static unsigned int base[5] = { 0x3f8, 0x2f8, 0x3e8, 0x2e8, 0x0 };
	int j;

	if (p_dev->io_lines > 3)
		return -ENODEV;

	p_dev->resource[0]->flags &= ~IO_DATA_PATH_WIDTH;
	p_dev->resource[0]->flags |= IO_DATA_PATH_WIDTH_8;
	p_dev->resource[0]->end = 8;

	for (j = 0; j < 5; j++) {
		p_dev->resource[0]->start = base[j];
		p_dev->io_lines = base[j] ? 16 : 3;
		if (!pcmcia_request_io(p_dev))
			return 0;
	}
	return -ENODEV;
}

static int btuart_config(struct pcmcia_device *link)
{
	struct btuart_info *info = link->priv;
	int i;
	int try;

	/* First pass: look for a config entry that looks normal.
	   Two tries: without IO aliases, then with aliases */
	for (try = 0; try < 2; try++)
		if (!pcmcia_loop_config(link, btuart_check_config, &try))
			goto found_port;

	/* Second pass: try to find an entry that isn't picky about
	   its base address, then try to grab any standard serial port
	   address, and finally try to get any free port. */
	if (!pcmcia_loop_config(link, btuart_check_config_notpicky, NULL))
		goto found_port;

	BT_ERR("No usable port range found");
	goto failed;

found_port:
	i = pcmcia_request_irq(link, btuart_interrupt);
	if (i != 0)
		goto failed;

	i = pcmcia_enable_device(link);
	if (i != 0)
		goto failed;

	if (btuart_open(info) != 0)
		goto failed;

	return 0;

failed:
	btuart_release(link);
	return -ENODEV;
}


static void btuart_release(struct pcmcia_device *link)
{
	struct btuart_info *info = link->priv;

	btuart_close(info);

	pcmcia_disable_device(link);
}

static const struct pcmcia_device_id btuart_ids[] = {
	/* don't use this driver. Use serial_cs + hci_uart instead */
	PCMCIA_DEVICE_NULL
};
MODULE_DEVICE_TABLE(pcmcia, btuart_ids);

static struct pcmcia_driver btuart_driver = {
	.owner		= THIS_MODULE,
	.name		= "btuart_cs",
	.probe		= btuart_probe,
	.remove		= btuart_detach,
	.id_table	= btuart_ids,
};
module_pcmcia_driver(btuart_driver);