/*
   *
   *  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) {

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

  			switch (hci_skb_pkt_type(info->rx_skb)) {

  
  			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",
  				       hci_skb_pkt_type(info->rx_skb));

  				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 (hci_skb_pkt_type(skb)) {

  	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), &hci_skb_pkt_type(skb), 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);