// SPDX-License-Identifier: GPL-2.0
/*
 * IPWireless 3G PCMCIA Network Driver
 *
 * Original code
 *   by Stephen Blackheath <stephen@blacksapphire.com>,
 *      Ben Martel <benm@symmetric.co.nz>
 *
 * Copyrighted as follows:
 *   Copyright (C) 2004 by Symmetric Systems Ltd (NZ)
 *
 * Various driver changes and rewrites, port to new kernels
 *   Copyright (C) 2006-2007 Jiri Kosina
 *
 * Misc code cleanups and updates
 *   Copyright (C) 2007 David Sterba
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/ppp_defs.h>
#include <linux/if.h>
#include <linux/ppp-ioctl.h>
#include <linux/sched.h>
#include <linux/serial.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/uaccess.h>

#include "tty.h"
#include "network.h"
#include "hardware.h"
#include "main.h"

#define IPWIRELESS_PCMCIA_START         (0)
#define IPWIRELESS_PCMCIA_MINORS        (24)
#define IPWIRELESS_PCMCIA_MINOR_RANGE   (8)

#define TTYTYPE_MODEM    (0)
#define TTYTYPE_MONITOR  (1)
#define TTYTYPE_RAS_RAW  (2)

struct ipw_tty {
        struct tty_port port;
        int index;
        struct ipw_hardware *hardware;
        unsigned int channel_idx;
        unsigned int secondary_channel_idx;
        int tty_type;
        struct ipw_network *network;
        unsigned int control_lines;
        struct mutex ipw_tty_mutex;
        int tx_bytes_queued;
};

static struct ipw_tty *ttys[IPWIRELESS_PCMCIA_MINORS];

static struct tty_driver *ipw_tty_driver;

static char *tty_type_name(int tty_type)
{
        static char *channel_names[] = {
                "modem",
                "monitor",
                "RAS-raw"
        };

        return channel_names[tty_type];
}

static struct ipw_tty *get_tty(int index)
{
        /*
         * The 'ras_raw' channel is only available when 'loopback' mode
         * is enabled.
         * Number of minor starts with 16 (_RANGE * _RAS_RAW).
         */
        if (!ipwireless_loopback && index >=
                         IPWIRELESS_PCMCIA_MINOR_RANGE * TTYTYPE_RAS_RAW)
                return NULL;

        return ttys[index];
}

static int ipw_open(struct tty_struct *linux_tty, struct file *filp)
{
        struct ipw_tty *tty = get_tty(linux_tty->index);

        if (!tty)
                return -ENODEV;

        mutex_lock(&tty->ipw_tty_mutex);
        if (tty->port.count == 0)
                tty->tx_bytes_queued = 0;

        tty->port.count++;

        tty->port.tty = linux_tty;
        linux_tty->driver_data = tty;

        if (tty->tty_type == TTYTYPE_MODEM)
                ipwireless_ppp_open(tty->network);

        mutex_unlock(&tty->ipw_tty_mutex);

        return 0;
}

static void do_ipw_close(struct ipw_tty *tty)
{
        tty->port.count--;

        if (tty->port.count == 0) {
                struct tty_struct *linux_tty = tty->port.tty;

                if (linux_tty != NULL) {
                        tty->port.tty = NULL;
                        linux_tty->driver_data = NULL;

                        if (tty->tty_type == TTYTYPE_MODEM)
                                ipwireless_ppp_close(tty->network);
                }
        }
}

static void ipw_hangup(struct tty_struct *linux_tty)
{
        struct ipw_tty *tty = linux_tty->driver_data;

        if (!tty)
                return;

        mutex_lock(&tty->ipw_tty_mutex);
        if (tty->port.count == 0) {
                mutex_unlock(&tty->ipw_tty_mutex);
                return;
        }

        do_ipw_close(tty);

        mutex_unlock(&tty->ipw_tty_mutex);
}

static void ipw_close(struct tty_struct *linux_tty, struct file *filp)
{
        ipw_hangup(linux_tty);
}

/* Take data received from hardware, and send it out the tty */
void ipwireless_tty_received(struct ipw_tty *tty, unsigned char *data,
                        unsigned int length)
{
        int work = 0;

        mutex_lock(&tty->ipw_tty_mutex);

        if (!tty->port.count) {
                mutex_unlock(&tty->ipw_tty_mutex);
                return;
        }
        mutex_unlock(&tty->ipw_tty_mutex);

        work = tty_insert_flip_string(&tty->port, data, length);

        if (work != length)
                printk(KERN_DEBUG IPWIRELESS_PCCARD_NAME
                                ": %d chars not inserted to flip buffer!\n",
                                length - work);

        if (work)
                tty_flip_buffer_push(&tty->port);
}

static void ipw_write_packet_sent_callback(void *callback_data,
                                           unsigned int packet_length)
{
        struct ipw_tty *tty = callback_data;

        /*
         * Packet has been sent, so we subtract the number of bytes from our
         * tally of outstanding TX bytes.
         */
        tty->tx_bytes_queued -= packet_length;
}

static ssize_t ipw_write(struct tty_struct *linux_tty, const u8 *buf,
                         size_t count)
{
        struct ipw_tty *tty = linux_tty->driver_data;
        int room, ret;

        if (!tty)
                return -ENODEV;

        mutex_lock(&tty->ipw_tty_mutex);
        if (!tty->port.count) {
                mutex_unlock(&tty->ipw_tty_mutex);
                return -EINVAL;
        }

        room = IPWIRELESS_TX_QUEUE_SIZE - tty->tx_bytes_queued;
        if (room < 0)
                room = 0;
        /* Don't allow caller to write any more than we have room for */
        if (count > room)
                count = room;

        if (count == 0) {
                mutex_unlock(&tty->ipw_tty_mutex);
                return 0;
        }

        ret = ipwireless_send_packet(tty->hardware, IPW_CHANNEL_RAS,
                               buf, count,
                               ipw_write_packet_sent_callback, tty);
        if (ret < 0) {
                mutex_unlock(&tty->ipw_tty_mutex);
                return 0;
        }

        tty->tx_bytes_queued += count;
        mutex_unlock(&tty->ipw_tty_mutex);

        return count;
}

static unsigned int ipw_write_room(struct tty_struct *linux_tty)
{
        struct ipw_tty *tty = linux_tty->driver_data;
        int room;

        /* FIXME: Exactly how is the tty object locked here .. */
        if (!tty)
                return 0;

        if (!tty->port.count)
                return 0;

        room = IPWIRELESS_TX_QUEUE_SIZE - tty->tx_bytes_queued;
        if (room < 0)
                room = 0;

        return room;
}

static int ipwireless_get_serial_info(struct tty_struct *linux_tty,
                                      struct serial_struct *ss)
{
        struct ipw_tty *tty = linux_tty->driver_data;

        if (!tty)
                return -ENODEV;

        if (!tty->port.count)
                return -EINVAL;

        ss->type = PORT_UNKNOWN;
        ss->line = tty->index;
        ss->baud_base = 115200;
        return 0;
}

static int ipwireless_set_serial_info(struct tty_struct *linux_tty,
                                      struct serial_struct *ss)
{
        return 0;       /* Keeps the PCMCIA scripts happy. */
}

static unsigned int ipw_chars_in_buffer(struct tty_struct *linux_tty)
{
        struct ipw_tty *tty = linux_tty->driver_data;

        if (!tty)
                return 0;

        if (!tty->port.count)
                return 0;

        return tty->tx_bytes_queued;
}

static int get_control_lines(struct ipw_tty *tty)
{
        unsigned int my = tty->control_lines;
        unsigned int out = 0;

        if (my & IPW_CONTROL_LINE_RTS)
                out |= TIOCM_RTS;
        if (my & IPW_CONTROL_LINE_DTR)
                out |= TIOCM_DTR;
        if (my & IPW_CONTROL_LINE_CTS)
                out |= TIOCM_CTS;
        if (my & IPW_CONTROL_LINE_DSR)
                out |= TIOCM_DSR;
        if (my & IPW_CONTROL_LINE_DCD)
                out |= TIOCM_CD;

        return out;
}

static int set_control_lines(struct ipw_tty *tty, unsigned int set,
                             unsigned int clear)
{
        int ret;

        if (set & TIOCM_RTS) {
                ret = ipwireless_set_RTS(tty->hardware, tty->channel_idx, 1);
                if (ret)
                        return ret;
                if (tty->secondary_channel_idx != -1) {
                        ret = ipwireless_set_RTS(tty->hardware,
                                          tty->secondary_channel_idx, 1);
                        if (ret)
                                return ret;
                }
        }
        if (set & TIOCM_DTR) {
                ret = ipwireless_set_DTR(tty->hardware, tty->channel_idx, 1);
                if (ret)
                        return ret;
                if (tty->secondary_channel_idx != -1) {
                        ret = ipwireless_set_DTR(tty->hardware,
                                          tty->secondary_channel_idx, 1);
                        if (ret)
                                return ret;
                }
        }
        if (clear & TIOCM_RTS) {
                ret = ipwireless_set_RTS(tty->hardware, tty->channel_idx, 0);
                if (tty->secondary_channel_idx != -1) {
                        ret = ipwireless_set_RTS(tty->hardware,
                                          tty->secondary_channel_idx, 0);
                        if (ret)
                                return ret;
                }
        }
        if (clear & TIOCM_DTR) {
                ret = ipwireless_set_DTR(tty->hardware, tty->channel_idx, 0);
                if (tty->secondary_channel_idx != -1) {
                        ret = ipwireless_set_DTR(tty->hardware,
                                          tty->secondary_channel_idx, 0);
                        if (ret)
                                return ret;
                }
        }
        return 0;
}

static int ipw_tiocmget(struct tty_struct *linux_tty)
{
        struct ipw_tty *tty = linux_tty->driver_data;
        /* FIXME: Exactly how is the tty object locked here .. */

        if (!tty)
                return -ENODEV;

        if (!tty->port.count)
                return -EINVAL;

        return get_control_lines(tty);
}

static int
ipw_tiocmset(struct tty_struct *linux_tty,
             unsigned int set, unsigned int clear)
{
        struct ipw_tty *tty = linux_tty->driver_data;
        /* FIXME: Exactly how is the tty object locked here .. */

        if (!tty)
                return -ENODEV;

        if (!tty->port.count)
                return -EINVAL;

        return set_control_lines(tty, set, clear);
}

static int ipw_ioctl(struct tty_struct *linux_tty,
                     unsigned int cmd, unsigned long arg)
{
        struct ipw_tty *tty = linux_tty->driver_data;

        if (!tty)
                return -ENODEV;

        if (!tty->port.count)
                return -EINVAL;

        /* FIXME: Exactly how is the tty object locked here .. */
        if (tty->tty_type == TTYTYPE_MODEM) {
                switch (cmd) {
                case PPPIOCGCHAN:
                        {
                                int chan = ipwireless_ppp_channel_index(
                                                        tty->network);

                                if (chan < 0)
                                        return -ENODEV;
                                if (put_user(chan, (int __user *) arg))
                                        return -EFAULT;
                        }
                        return 0;

                case PPPIOCGUNIT:
                        {
                                int unit = ipwireless_ppp_unit_number(
                                                tty->network);

                                if (unit < 0)
                                        return -ENODEV;
                                if (put_user(unit, (int __user *) arg))
                                        return -EFAULT;
                        }
                        return 0;

                case FIONREAD:
                        {
                                int val = 0;

                                if (put_user(val, (int __user *) arg))
                                        return -EFAULT;
                        }
                        return 0;
                case TCFLSH:
                        return tty_perform_flush(linux_tty, arg);
                }
        }
        return -ENOIOCTLCMD;
}

static int add_tty(int j,
                    struct ipw_hardware *hardware,
                    struct ipw_network *network, int channel_idx,
                    int secondary_channel_idx, int tty_type)
{
        ttys[j] = kzalloc_obj(struct ipw_tty);
        if (!ttys[j])
                return -ENOMEM;
        ttys[j]->index = j;
        ttys[j]->hardware = hardware;
        ttys[j]->channel_idx = channel_idx;
        ttys[j]->secondary_channel_idx = secondary_channel_idx;
        ttys[j]->network = network;
        ttys[j]->tty_type = tty_type;
        mutex_init(&ttys[j]->ipw_tty_mutex);
        tty_port_init(&ttys[j]->port);

        tty_port_register_device(&ttys[j]->port, ipw_tty_driver, j, NULL);
        ipwireless_associate_network_tty(network, channel_idx, ttys[j]);

        if (secondary_channel_idx != -1)
                ipwireless_associate_network_tty(network,
                                                 secondary_channel_idx,
                                                 ttys[j]);
        /* check if we provide raw device (if loopback is enabled) */
        if (get_tty(j))
                printk(KERN_INFO IPWIRELESS_PCCARD_NAME
                       ": registering %s device ttyIPWp%d\n",
                       tty_type_name(tty_type), j);

        return 0;
}

struct ipw_tty *ipwireless_tty_create(struct ipw_hardware *hardware,
                                      struct ipw_network *network)
{
        int i, j;

        for (i = 0; i < IPWIRELESS_PCMCIA_MINOR_RANGE; i++) {
                int allfree = 1;

                for (j = i; j < IPWIRELESS_PCMCIA_MINORS;
                                j += IPWIRELESS_PCMCIA_MINOR_RANGE)
                        if (ttys[j] != NULL) {
                                allfree = 0;
                                break;
                        }

                if (allfree) {
                        j = i;

                        if (add_tty(j, hardware, network,
                                        IPW_CHANNEL_DIALLER, IPW_CHANNEL_RAS,
                                        TTYTYPE_MODEM))
                                return NULL;

                        j += IPWIRELESS_PCMCIA_MINOR_RANGE;
                        if (add_tty(j, hardware, network,
                                        IPW_CHANNEL_DIALLER, -1,
                                        TTYTYPE_MONITOR))
                                return NULL;

                        j += IPWIRELESS_PCMCIA_MINOR_RANGE;
                        if (add_tty(j, hardware, network,
                                        IPW_CHANNEL_RAS, -1,
                                        TTYTYPE_RAS_RAW))
                                return NULL;

                        return ttys[i];
                }
        }
        return NULL;
}

/*
 * Must be called before ipwireless_network_free().
 */
void ipwireless_tty_free(struct ipw_tty *tty)
{
        int j;
        struct ipw_network *network = ttys[tty->index]->network;

        for (j = tty->index; j < IPWIRELESS_PCMCIA_MINORS;
                        j += IPWIRELESS_PCMCIA_MINOR_RANGE) {
                struct ipw_tty *ttyj = ttys[j];

                if (ttyj) {
                        mutex_lock(&ttyj->ipw_tty_mutex);
                        if (get_tty(j))
                                printk(KERN_INFO IPWIRELESS_PCCARD_NAME
                                       ": deregistering %s device ttyIPWp%d\n",
                                       tty_type_name(ttyj->tty_type), j);
                        if (ttyj->port.tty != NULL) {
                                mutex_unlock(&ttyj->ipw_tty_mutex);
                                tty_vhangup(ttyj->port.tty);
                                /* FIXME: Exactly how is the tty object locked here
                                   against a parallel ioctl etc */
                                /* FIXME2: hangup does not mean all processes
                                 * are gone */
                                mutex_lock(&ttyj->ipw_tty_mutex);
                        }
                        while (ttyj->port.count)
                                do_ipw_close(ttyj);
                        ipwireless_disassociate_network_ttys(network,
                                                             ttyj->channel_idx);
                        tty_unregister_device(ipw_tty_driver, j);
                        tty_port_destroy(&ttyj->port);
                        ttys[j] = NULL;
                        mutex_unlock(&ttyj->ipw_tty_mutex);
                        kfree(ttyj);
                }
        }
}

static const struct tty_operations tty_ops = {
        .open = ipw_open,
        .close = ipw_close,
        .hangup = ipw_hangup,
        .write = ipw_write,
        .write_room = ipw_write_room,
        .ioctl = ipw_ioctl,
        .chars_in_buffer = ipw_chars_in_buffer,
        .tiocmget = ipw_tiocmget,
        .tiocmset = ipw_tiocmset,
        .set_serial = ipwireless_set_serial_info,
        .get_serial = ipwireless_get_serial_info,
};

int ipwireless_tty_init(void)
{
        int result;

        ipw_tty_driver = tty_alloc_driver(IPWIRELESS_PCMCIA_MINORS,
                        TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV);
        if (IS_ERR(ipw_tty_driver))
                return PTR_ERR(ipw_tty_driver);

        ipw_tty_driver->driver_name = IPWIRELESS_PCCARD_NAME;
        ipw_tty_driver->name = "ttyIPWp";
        ipw_tty_driver->major = 0;
        ipw_tty_driver->minor_start = IPWIRELESS_PCMCIA_START;
        ipw_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
        ipw_tty_driver->subtype = SERIAL_TYPE_NORMAL;
        ipw_tty_driver->init_termios = tty_std_termios;
        ipw_tty_driver->init_termios.c_cflag =
            B9600 | CS8 | CREAD | HUPCL | CLOCAL;
        ipw_tty_driver->init_termios.c_ispeed = 9600;
        ipw_tty_driver->init_termios.c_ospeed = 9600;
        tty_set_operations(ipw_tty_driver, &tty_ops);
        result = tty_register_driver(ipw_tty_driver);
        if (result) {
                printk(KERN_ERR IPWIRELESS_PCCARD_NAME
                       ": failed to register tty driver\n");
                tty_driver_kref_put(ipw_tty_driver);
                return result;
        }

        return 0;
}

void ipwireless_tty_release(void)
{
        tty_unregister_driver(ipw_tty_driver);
        tty_driver_kref_put(ipw_tty_driver);
}

int ipwireless_tty_is_modem(struct ipw_tty *tty)
{
        return tty->tty_type == TTYTYPE_MODEM;
}

void
ipwireless_tty_notify_control_line_change(struct ipw_tty *tty,
                                          unsigned int channel_idx,
                                          unsigned int control_lines,
                                          unsigned int changed_mask)
{
        unsigned int old_control_lines = tty->control_lines;

        tty->control_lines = (tty->control_lines & ~changed_mask)
                | (control_lines & changed_mask);

        /*
         * If DCD is de-asserted, we close the tty so pppd can tell that we
         * have gone offline.
         */
        if ((old_control_lines & IPW_CONTROL_LINE_DCD)
                        && !(tty->control_lines & IPW_CONTROL_LINE_DCD)
                        && tty->port.tty) {
                tty_hangup(tty->port.tty);
        }
}