// SPDX-License-Identifier: GPL-2.0+
/*
 *  KOBIL USB Smart Card Terminal Driver
 *
 *  Copyright (C) 2002  KOBIL Systems GmbH
 *  Author: Thomas Wahrenbruch
 *
 *  Contact: linuxusb@kobil.de
 *
 *  This program is largely derived from work by the linux-usb group
 *  and associated source files.  Please see the usb/serial files for
 *  individual credits and copyrights.
 *
 *  Thanks to Greg Kroah-Hartman (greg@kroah.com) for his help and
 *  patience.
 *
 * Supported readers: USB TWIN, KAAN Standard Plus and SecOVID Reader Plus
 * (Adapter K), B1 Professional and KAAN Professional (Adapter B)
 */


#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/ioctl.h>
#include "kobil_sct.h"

#define DRIVER_AUTHOR "KOBIL Systems GmbH - http://www.kobil.com"
#define DRIVER_DESC "KOBIL USB Smart Card Terminal Driver (experimental)"

#define KOBIL_VENDOR_ID                 0x0D46
#define KOBIL_ADAPTER_B_PRODUCT_ID      0x2011
#define KOBIL_ADAPTER_K_PRODUCT_ID      0x2012
#define KOBIL_USBTWIN_PRODUCT_ID        0x0078
#define KOBIL_KAAN_SIM_PRODUCT_ID       0x0081

#define KOBIL_TIMEOUT           500
#define KOBIL_BUF_LENGTH        300


/* Function prototypes */
static int kobil_port_probe(struct usb_serial_port *probe);
static void kobil_port_remove(struct usb_serial_port *probe);
static int  kobil_open(struct tty_struct *tty, struct usb_serial_port *port);
static void kobil_close(struct usb_serial_port *port);
static int  kobil_write(struct tty_struct *tty, struct usb_serial_port *port,
                         const unsigned char *buf, int count);
static unsigned int kobil_write_room(struct tty_struct *tty);
static int  kobil_ioctl(struct tty_struct *tty,
                        unsigned int cmd, unsigned long arg);
static int  kobil_tiocmget(struct tty_struct *tty);
static int  kobil_tiocmset(struct tty_struct *tty,
                           unsigned int set, unsigned int clear);
static void kobil_read_int_callback(struct urb *urb);
static void kobil_write_int_callback(struct urb *urb);
static void kobil_set_termios(struct tty_struct *tty,
                              struct usb_serial_port *port,
                              const struct ktermios *old);
static void kobil_init_termios(struct tty_struct *tty);

static const struct usb_device_id id_table[] = {
        { USB_DEVICE(KOBIL_VENDOR_ID, KOBIL_ADAPTER_B_PRODUCT_ID) },
        { USB_DEVICE(KOBIL_VENDOR_ID, KOBIL_ADAPTER_K_PRODUCT_ID) },
        { USB_DEVICE(KOBIL_VENDOR_ID, KOBIL_USBTWIN_PRODUCT_ID) },
        { USB_DEVICE(KOBIL_VENDOR_ID, KOBIL_KAAN_SIM_PRODUCT_ID) },
        { }                     /* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, id_table);

static struct usb_serial_driver kobil_device = {
        .driver = {
                .name =         "kobil",
        },
        .description =          "KOBIL USB smart card terminal",
        .id_table =             id_table,
        .num_ports =            1,
        .num_interrupt_out =    1,
        .port_probe =           kobil_port_probe,
        .port_remove =          kobil_port_remove,
        .ioctl =                kobil_ioctl,
        .set_termios =          kobil_set_termios,
        .init_termios =         kobil_init_termios,
        .tiocmget =             kobil_tiocmget,
        .tiocmset =             kobil_tiocmset,
        .open =                 kobil_open,
        .close =                kobil_close,
        .write =                kobil_write,
        .write_room =           kobil_write_room,
        .read_int_callback =    kobil_read_int_callback,
        .write_int_callback =   kobil_write_int_callback,
};

static struct usb_serial_driver * const serial_drivers[] = {
        &kobil_device, NULL
};

struct kobil_private {
        unsigned char buf[KOBIL_BUF_LENGTH]; /* buffer for the APDU to send */
        int filled;  /* index of the last char in buf */
        int cur_pos; /* index of the next char to send in buf */
        __u16 device_type;
};

static int kobil_ctrl_send(struct usb_serial_port *port, u8 req, u16 val)
{
        return usb_control_msg(port->serial->dev,
                        usb_sndctrlpipe(port->serial->dev, 0),
                        req, USB_TYPE_VENDOR | USB_RECIP_ENDPOINT | USB_DIR_OUT,
                        val, 0, NULL, 0, KOBIL_TIMEOUT);
}

static int kobil_ctrl_recv(struct usb_serial_port *port, u8 req, u16 val, void *buf, u16 size)
{
        return usb_control_msg(port->serial->dev,
                        usb_rcvctrlpipe(port->serial->dev, 0),
                        req, USB_TYPE_VENDOR | USB_RECIP_ENDPOINT | USB_DIR_IN,
                        val, 0, buf, size, KOBIL_TIMEOUT);
}

static int kobil_port_probe(struct usb_serial_port *port)
{
        struct usb_serial *serial = port->serial;
        struct kobil_private *priv;

        priv = kmalloc_obj(struct kobil_private);
        if (!priv)
                return -ENOMEM;

        priv->filled = 0;
        priv->cur_pos = 0;
        priv->device_type = le16_to_cpu(serial->dev->descriptor.idProduct);

        switch (priv->device_type) {
        case KOBIL_ADAPTER_B_PRODUCT_ID:
                dev_dbg(&serial->dev->dev, "KOBIL B1 PRO / KAAN PRO detected\n");
                break;
        case KOBIL_ADAPTER_K_PRODUCT_ID:
                dev_dbg(&serial->dev->dev, "KOBIL KAAN Standard Plus / SecOVID Reader Plus detected\n");
                break;
        case KOBIL_USBTWIN_PRODUCT_ID:
                dev_dbg(&serial->dev->dev, "KOBIL USBTWIN detected\n");
                break;
        case KOBIL_KAAN_SIM_PRODUCT_ID:
                dev_dbg(&serial->dev->dev, "KOBIL KAAN SIM detected\n");
                break;
        }
        usb_set_serial_port_data(port, priv);

        return 0;
}


static void kobil_port_remove(struct usb_serial_port *port)
{
        struct kobil_private *priv;

        priv = usb_get_serial_port_data(port);
        kfree(priv);
}

static void kobil_init_termios(struct tty_struct *tty)
{
        /* Default to echo off and other sane device settings */
        tty->termios.c_lflag = 0;
        tty->termios.c_iflag = IGNBRK | IGNPAR | IXOFF;
        /* do NOT translate CR to CR-NL (0x0A -> 0x0A 0x0D) */
        tty->termios.c_oflag &= ~ONLCR;
}

static int kobil_open(struct tty_struct *tty, struct usb_serial_port *port)
{
        struct device *dev = &port->dev;
        struct kobil_private *priv;
        unsigned char *transfer_buffer;
        int transfer_buffer_length = 8;
        int result;

        priv = usb_get_serial_port_data(port);

        /* allocate memory for transfer buffer */
        transfer_buffer = kzalloc(transfer_buffer_length, GFP_KERNEL);
        if (!transfer_buffer)
                return -ENOMEM;

        /* get hardware version */
        result = kobil_ctrl_recv(port, SUSBCRequest_GetMisc, SUSBCR_MSC_GetHWVersion,
                        transfer_buffer, transfer_buffer_length);
        dev_dbg(dev, "%s - Send get_HW_version URB returns: %i\n", __func__, result);
        if (result >= 3) {
                dev_dbg(dev, "Hardware version: %i.%i.%i\n", transfer_buffer[0],
                                transfer_buffer[1], transfer_buffer[2]);
        }

        /* get firmware version */
        result = kobil_ctrl_recv(port, SUSBCRequest_GetMisc, SUSBCR_MSC_GetFWVersion,
                        transfer_buffer, transfer_buffer_length);
        dev_dbg(dev, "%s - Send get_FW_version URB returns: %i\n", __func__, result);
        if (result >= 3) {
                dev_dbg(dev, "Firmware version: %i.%i.%i\n", transfer_buffer[0],
                                transfer_buffer[1], transfer_buffer[2]);
        }

        if (priv->device_type == KOBIL_ADAPTER_B_PRODUCT_ID ||
                        priv->device_type == KOBIL_ADAPTER_K_PRODUCT_ID) {
                /* Setting Baudrate, Parity and Stopbits */
                result = kobil_ctrl_send(port, SUSBCRequest_SetBaudRateParityAndStopBits,
                                SUSBCR_SBR_9600 | SUSBCR_SPASB_EvenParity | SUSBCR_SPASB_1StopBit);
                dev_dbg(dev, "%s - Send set_baudrate URB returns: %i\n", __func__, result);

                /* reset all queues */
                result = kobil_ctrl_send(port, SUSBCRequest_Misc, SUSBCR_MSC_ResetAllQueues);
                dev_dbg(dev, "%s - Send reset_all_queues URB returns: %i\n", __func__, result);
        }
        if (priv->device_type == KOBIL_USBTWIN_PRODUCT_ID ||
                        priv->device_type == KOBIL_ADAPTER_B_PRODUCT_ID ||
                        priv->device_type == KOBIL_KAAN_SIM_PRODUCT_ID) {
                /* start reading (Adapter B 'cause PNP string) */
                result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
                dev_dbg(dev, "%s - Send read URB returns: %i\n", __func__, result);
        }

        kfree(transfer_buffer);
        return 0;
}


static void kobil_close(struct usb_serial_port *port)
{
        /* FIXME: Add rts/dtr methods */
        usb_kill_urb(port->interrupt_out_urb);
        usb_kill_urb(port->interrupt_in_urb);
}


static void kobil_read_int_callback(struct urb *urb)
{
        int result;
        struct usb_serial_port *port = urb->context;
        unsigned char *data = urb->transfer_buffer;
        int status = urb->status;

        if (status) {
                dev_dbg(&port->dev, "%s - Read int status not zero: %d\n", __func__, status);
                return;
        }

        if (urb->actual_length) {
                usb_serial_debug_data(&port->dev, __func__, urb->actual_length,
                                                                        data);
                tty_insert_flip_string(&port->port, data, urb->actual_length);
                tty_flip_buffer_push(&port->port);
        }

        result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
        dev_dbg(&port->dev, "%s - Send read URB returns: %i\n", __func__, result);
}


static void kobil_write_int_callback(struct urb *urb)
{
}


static int kobil_write(struct tty_struct *tty, struct usb_serial_port *port,
                        const unsigned char *buf, int count)
{
        struct kobil_private *priv;
        int length, todo, result;

        if (count == 0) {
                dev_dbg(&port->dev, "%s - write request of 0 bytes\n", __func__);
                return 0;
        }

        priv = usb_get_serial_port_data(port);

        if (count > (KOBIL_BUF_LENGTH - priv->filled)) {
                dev_dbg(&port->dev, "%s - Error: write request bigger than buffer size\n", __func__);
                return -ENOMEM;
        }

        /* Copy data to buffer */
        memcpy(priv->buf + priv->filled, buf, count);
        usb_serial_debug_data(&port->dev, __func__, count, priv->buf + priv->filled);
        priv->filled = priv->filled + count;

        /* only send complete block. TWIN, KAAN SIM and adapter K
           use the same protocol. */
        if (((priv->device_type != KOBIL_ADAPTER_B_PRODUCT_ID) && (priv->filled > 2) && (priv->filled >= (priv->buf[1] + 3))) ||
             ((priv->device_type == KOBIL_ADAPTER_B_PRODUCT_ID) && (priv->filled > 3) && (priv->filled >= (priv->buf[2] + 4)))) {
                /* stop reading (except TWIN and KAAN SIM) */
                if (priv->device_type == KOBIL_ADAPTER_B_PRODUCT_ID ||
                                priv->device_type == KOBIL_ADAPTER_K_PRODUCT_ID) {
                        usb_kill_urb(port->interrupt_in_urb);
                }

                todo = priv->filled - priv->cur_pos;

                while (todo > 0) {
                        /* max 8 byte in one urb (endpoint size) */
                        length = min(todo, port->interrupt_out_size);
                        /* copy data to transfer buffer */
                        memcpy(port->interrupt_out_buffer,
                                        priv->buf + priv->cur_pos, length);
                        port->interrupt_out_urb->transfer_buffer_length = length;

                        priv->cur_pos = priv->cur_pos + length;
                        result = usb_submit_urb(port->interrupt_out_urb,
                                        GFP_ATOMIC);
                        dev_dbg(&port->dev, "%s - Send write URB returns: %i\n", __func__, result);
                        todo = priv->filled - priv->cur_pos;

                        if (todo > 0)
                                msleep(24);
                }

                priv->filled = 0;
                priv->cur_pos = 0;

                /* start reading (except TWIN and KAAN SIM) */
                if (priv->device_type == KOBIL_ADAPTER_B_PRODUCT_ID ||
                                priv->device_type == KOBIL_ADAPTER_K_PRODUCT_ID) {
                        result = usb_submit_urb(port->interrupt_in_urb,
                                        GFP_ATOMIC);
                        dev_dbg(&port->dev, "%s - Send read URB returns: %i\n", __func__, result);
                }
        }
        return count;
}


static unsigned int kobil_write_room(struct tty_struct *tty)
{
        /* FIXME */
        return 8;
}


static int kobil_tiocmget(struct tty_struct *tty)
{
        struct usb_serial_port *port = tty->driver_data;
        struct kobil_private *priv;
        int result;
        unsigned char *transfer_buffer;
        int transfer_buffer_length = 8;

        priv = usb_get_serial_port_data(port);
        if (priv->device_type == KOBIL_USBTWIN_PRODUCT_ID ||
                        priv->device_type == KOBIL_KAAN_SIM_PRODUCT_ID) {
                /* This device doesn't support ioctl calls */
                return -EINVAL;
        }

        /* allocate memory for transfer buffer */
        transfer_buffer = kzalloc(transfer_buffer_length, GFP_KERNEL);
        if (!transfer_buffer)
                return -ENOMEM;

        result = kobil_ctrl_recv(port, SUSBCRequest_GetStatusLineState, 0,
                        transfer_buffer, transfer_buffer_length);
        dev_dbg(&port->dev, "Send get_status_line_state URB returns: %i\n",
                        result);
        if (result < 1) {
                if (result >= 0)
                        result = -EIO;
                goto out_free;
        }

        dev_dbg(&port->dev, "Statusline: %02x\n", transfer_buffer[0]);

        result = 0;
        if ((transfer_buffer[0] & SUSBCR_GSL_DSR) != 0)
                result = TIOCM_DSR;
out_free:
        kfree(transfer_buffer);
        return result;
}

static int kobil_tiocmset(struct tty_struct *tty,
                           unsigned int set, unsigned int clear)
{
        struct usb_serial_port *port = tty->driver_data;
        struct device *dev = &port->dev;
        struct kobil_private *priv;
        int dtr, rts;
        int result;
        u16 val = 0;

        priv = usb_get_serial_port_data(port);
        if (priv->device_type == KOBIL_USBTWIN_PRODUCT_ID ||
                        priv->device_type == KOBIL_KAAN_SIM_PRODUCT_ID) {
                /* This device doesn't support ioctl calls */
                return -EINVAL;
        }

        dtr = (set | clear) & TIOCM_DTR;
        rts = (set | clear) & TIOCM_RTS;

        if (dtr && priv->device_type == KOBIL_ADAPTER_B_PRODUCT_ID) {
                if (set & TIOCM_DTR)
                        val = SUSBCR_SSL_SETDTR;
                else
                        val = SUSBCR_SSL_CLRDTR;
        } else if (rts) {
                if (set & TIOCM_RTS)
                        val = SUSBCR_SSL_SETRTS;
                else
                        val = SUSBCR_SSL_CLRRTS;
        }

        if (val) {
                result = kobil_ctrl_send(port, SUSBCRequest_SetStatusLinesOrQueues, val);
                if (result < 0) {
                        dev_err(dev, "failed to set status lines: %d\n", result);
                        return result;
                }
        }

        return 0;
}

static void kobil_set_termios(struct tty_struct *tty,
                              struct usb_serial_port *port,
                              const struct ktermios *old)
{
        struct kobil_private *priv;
        int result;
        int c_cflag = tty->termios.c_cflag;
        speed_t speed;
        u16 val;

        priv = usb_get_serial_port_data(port);
        if (priv->device_type == KOBIL_USBTWIN_PRODUCT_ID ||
                        priv->device_type == KOBIL_KAAN_SIM_PRODUCT_ID) {
                /* This device doesn't support ioctl calls */
                tty_termios_copy_hw(&tty->termios, old);
                return;
        }

        speed = tty_get_baud_rate(tty);
        switch (speed) {
        case 1200:
                val = SUSBCR_SBR_1200;
                break;
        default:
                speed = 9600;
                fallthrough;
        case 9600:
                val = SUSBCR_SBR_9600;
                break;
        }

        if (c_cflag & CSTOPB)
                val |= SUSBCR_SPASB_2StopBits;
        else
                val |= SUSBCR_SPASB_1StopBit;

        if (c_cflag & PARENB) {
                if  (c_cflag & PARODD)
                        val |= SUSBCR_SPASB_OddParity;
                else
                        val |= SUSBCR_SPASB_EvenParity;
        } else {
                val |= SUSBCR_SPASB_NoParity;
        }

        tty->termios.c_cflag &= ~CMSPAR;
        tty_encode_baud_rate(tty, speed, speed);

        result = kobil_ctrl_send(port, SUSBCRequest_SetBaudRateParityAndStopBits, val);
        if (result) {
                dev_err(&port->dev, "failed to update line settings: %d\n",
                                result);
        }
}

static int kobil_ioctl(struct tty_struct *tty,
                                        unsigned int cmd, unsigned long arg)
{
        struct usb_serial_port *port = tty->driver_data;
        struct kobil_private *priv = usb_get_serial_port_data(port);
        int result;

        if (priv->device_type == KOBIL_USBTWIN_PRODUCT_ID ||
                        priv->device_type == KOBIL_KAAN_SIM_PRODUCT_ID)
                /* This device doesn't support ioctl calls */
                return -ENOIOCTLCMD;

        switch (cmd) {
        case TCFLSH:
                result = kobil_ctrl_send(port, SUSBCRequest_Misc, SUSBCR_MSC_ResetAllQueues);
                dev_dbg(&port->dev,
                        "%s - Send reset_all_queues (FLUSH) URB returns: %i\n",
                        __func__, result);
                return (result < 0) ? -EIO: 0;
        default:
                return -ENOIOCTLCMD;
        }
}

module_usb_serial_driver(serial_drivers, id_table);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");