// SPDX-License-Identifier: GPL-2.0-or-later
/*
        CA-driver for TwinHan DST Frontend/Card

        Copyright (C) 2004, 2005 Manu Abraham (manu@kromtek.com)

*/

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/string.h>
#include <linux/dvb/ca.h>
#include <media/dvbdev.h>
#include <media/dvb_frontend.h>
#include "dst_ca.h"
#include "dst_common.h"

#define DST_CA_ERROR            0
#define DST_CA_NOTICE           1
#define DST_CA_INFO             2
#define DST_CA_DEBUG            3

#define dprintk(x, y, z, format, arg...) do {                                           \
        if (z) {                                                                        \
                if      ((x > DST_CA_ERROR) && (x > y))                                 \
                        printk(KERN_ERR "%s: " format "\n", __func__ , ##arg);  \
                else if ((x > DST_CA_NOTICE) && (x > y))                                \
                        printk(KERN_NOTICE "%s: " format "\n", __func__ , ##arg);       \
                else if ((x > DST_CA_INFO) && (x > y))                                  \
                        printk(KERN_INFO "%s: " format "\n", __func__ , ##arg); \
                else if ((x > DST_CA_DEBUG) && (x > y))                                 \
                        printk(KERN_DEBUG "%s: " format "\n", __func__ , ##arg);        \
        } else {                                                                        \
                if (x > y)                                                              \
                        printk(format, ## arg);                                         \
        }                                                                               \
} while(0)


static DEFINE_MUTEX(dst_ca_mutex);
static unsigned int verbose = 5;
module_param(verbose, int, 0644);
MODULE_PARM_DESC(verbose, "verbose startup messages, default is 1 (yes)");

static void put_command_and_length(u8 *data, int command, int length)
{
        data[0] = (command >> 16) & 0xff;
        data[1] = (command >> 8) & 0xff;
        data[2] = command & 0xff;
        data[3] = length;
}

static void put_checksum(u8 *check_string, int length)
{
        dprintk(verbose, DST_CA_DEBUG, 1, " Computing string checksum.");
        dprintk(verbose, DST_CA_DEBUG, 1, "  -> string length : 0x%02x", length);
        check_string[length] = dst_check_sum (check_string, length);
        dprintk(verbose, DST_CA_DEBUG, 1, "  -> checksum      : 0x%02x", check_string[length]);
}

static int dst_ci_command(struct dst_state* state, u8 * data, u8 *ca_string, u8 len, int read)
{
        u8 reply;

        mutex_lock(&state->dst_mutex);
        dst_comm_init(state);
        msleep(65);

        if (write_dst(state, data, len)) {
                dprintk(verbose, DST_CA_INFO, 1, " Write not successful, trying to recover");
                dst_error_recovery(state);
                goto error;
        }
        if ((dst_pio_disable(state)) < 0) {
                dprintk(verbose, DST_CA_ERROR, 1, " DST PIO disable failed.");
                goto error;
        }
        if (read_dst(state, &reply, GET_ACK) < 0) {
                dprintk(verbose, DST_CA_INFO, 1, " Read not successful, trying to recover");
                dst_error_recovery(state);
                goto error;
        }
        if (read) {
                if (! dst_wait_dst_ready(state, LONG_DELAY)) {
                        dprintk(verbose, DST_CA_NOTICE, 1, " 8820 not ready");
                        goto error;
                }
                if (read_dst(state, ca_string, 128) < 0) {      /*      Try to make this dynamic        */
                        dprintk(verbose, DST_CA_INFO, 1, " Read not successful, trying to recover");
                        dst_error_recovery(state);
                        goto error;
                }
        }
        mutex_unlock(&state->dst_mutex);
        return 0;

error:
        mutex_unlock(&state->dst_mutex);
        return -EIO;
}


static int dst_put_ci(struct dst_state *state, u8 *data, int len, u8 *ca_string, int read)
{
        u8 dst_ca_comm_err = 0;

        while (dst_ca_comm_err < RETRIES) {
                dprintk(verbose, DST_CA_NOTICE, 1, " Put Command");
                if (dst_ci_command(state, data, ca_string, len, read)) {        // If error
                        dst_error_recovery(state);
                        dst_ca_comm_err++; // work required here.
                } else {
                        break;
                }
        }

        if(dst_ca_comm_err == RETRIES)
                return -EIO;

        return 0;
}



static int ca_get_app_info(struct dst_state *state)
{
        int length, str_length;
        static u8 command[8] = {0x07, 0x40, 0x01, 0x00, 0x01, 0x00, 0x00, 0xff};

        put_checksum(&command[0], command[0]);
        if ((dst_put_ci(state, command, sizeof(command), state->messages, GET_REPLY)) < 0) {
                dprintk(verbose, DST_CA_ERROR, 1, " -->dst_put_ci FAILED !");
                return -EIO;
        }
        dprintk(verbose, DST_CA_INFO, 1, " -->dst_put_ci SUCCESS !");
        dprintk(verbose, DST_CA_INFO, 1, " ================================ CI Module Application Info ======================================");
        dprintk(verbose, DST_CA_INFO, 1, " Application Type=[%d], Application Vendor=[%d], Vendor Code=[%d]\n%s: Application info=[%s]",
                state->messages[7], (state->messages[8] << 8) | state->messages[9],
                (state->messages[10] << 8) | state->messages[11], __func__, (char *)(&state->messages[12]));
        dprintk(verbose, DST_CA_INFO, 1, " ==================================================================================================");

        // Transform dst message to correct application_info message
        length = state->messages[5];
        str_length = length - 6;
        if (str_length < 0) {
                str_length = 0;
                dprintk(verbose, DST_CA_ERROR, 1, "Invalid string length returned in ca_get_app_info(). Recovering.");
        }

        // First, the command and length fields
        put_command_and_length(&state->messages[0], CA_APP_INFO, length);

        // Copy application_type, application_manufacturer and manufacturer_code
        memmove(&state->messages[4], &state->messages[7], 5);

        // Set string length and copy string
        state->messages[9] = str_length;
        memmove(&state->messages[10], &state->messages[12], str_length);

        return 0;
}

static int ca_get_ca_info(struct dst_state *state)
{
        int srcPtr, dstPtr, i, num_ids;
        static u8 slot_command[8] = {0x07, 0x40, 0x00, 0x00, 0x02, 0x00, 0x00, 0xff};
        const int in_system_id_pos = 8, out_system_id_pos = 4, in_num_ids_pos = 7;

        put_checksum(&slot_command[0], slot_command[0]);
        if ((dst_put_ci(state, slot_command, sizeof (slot_command), state->messages, GET_REPLY)) < 0) {
                dprintk(verbose, DST_CA_ERROR, 1, " -->dst_put_ci FAILED !");
                return -EIO;
        }
        dprintk(verbose, DST_CA_INFO, 1, " -->dst_put_ci SUCCESS !");

        // Print raw data
        dprintk(verbose, DST_CA_INFO, 0, " DST data = [");
        for (i = 0; i < state->messages[0] + 1; i++) {
                dprintk(verbose, DST_CA_INFO, 0, " 0x%02x", state->messages[i]);
        }
        dprintk(verbose, DST_CA_INFO, 0, "]\n");

        // Set the command and length of the output
        num_ids = state->messages[in_num_ids_pos];
        if (num_ids >= 100) {
                num_ids = 100;
                dprintk(verbose, DST_CA_ERROR, 1, "Invalid number of ids (>100). Recovering.");
        }
        put_command_and_length(&state->messages[0], CA_INFO, num_ids * 2);

        dprintk(verbose, DST_CA_INFO, 0, " CA_INFO = [");
        srcPtr = in_system_id_pos;
        dstPtr = out_system_id_pos;
        for(i = 0; i < num_ids; i++) {
                dprintk(verbose, DST_CA_INFO, 0, " 0x%02x%02x", state->messages[srcPtr + 0], state->messages[srcPtr + 1]);
                // Append to output
                state->messages[dstPtr + 0] = state->messages[srcPtr + 0];
                state->messages[dstPtr + 1] = state->messages[srcPtr + 1];
                srcPtr += 2;
                dstPtr += 2;
        }
        dprintk(verbose, DST_CA_INFO, 0, "]\n");

        return 0;
}

static int ca_get_slot_caps(struct dst_state *state, struct ca_caps *p_ca_caps, void __user *arg)
{
        int i;
        u8 slot_cap[256];
        static u8 slot_command[8] = {0x07, 0x40, 0x02, 0x00, 0x02, 0x00, 0x00, 0xff};

        put_checksum(&slot_command[0], slot_command[0]);
        if ((dst_put_ci(state, slot_command, sizeof (slot_command), slot_cap, GET_REPLY)) < 0) {
                dprintk(verbose, DST_CA_ERROR, 1, " -->dst_put_ci FAILED !");
                return -EIO;
        }
        dprintk(verbose, DST_CA_NOTICE, 1, " -->dst_put_ci SUCCESS !");

        /*      Will implement the rest soon            */

        dprintk(verbose, DST_CA_INFO, 1, " Slot cap = [%d]", slot_cap[7]);
        dprintk(verbose, DST_CA_INFO, 0, "===================================\n");
        for (i = 0; i < slot_cap[0] + 1; i++)
                dprintk(verbose, DST_CA_INFO, 0, " %d", slot_cap[i]);
        dprintk(verbose, DST_CA_INFO, 0, "\n");

        p_ca_caps->slot_num = 1;
        p_ca_caps->slot_type = 1;
        p_ca_caps->descr_num = slot_cap[7];
        p_ca_caps->descr_type = 1;

        if (copy_to_user(arg, p_ca_caps, sizeof (struct ca_caps)))
                return -EFAULT;

        return 0;
}

/*      Need some more work     */
static int ca_get_slot_descr(struct dst_state *state, struct ca_msg *p_ca_message, void __user *arg)
{
        return -EOPNOTSUPP;
}


static int ca_get_slot_info(struct dst_state *state, struct ca_slot_info *p_ca_slot_info, void __user *arg)
{
        int i;
        static u8 slot_command[8] = {0x00, 0x05, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff};

        u8 *slot_info = state->messages;

        put_checksum(&slot_command[0], 7);
        if ((dst_put_ci(state, slot_command, sizeof (slot_command), slot_info, GET_REPLY)) < 0) {
                dprintk(verbose, DST_CA_ERROR, 1, " -->dst_put_ci FAILED !");
                return -EIO;
        }
        dprintk(verbose, DST_CA_INFO, 1, " -->dst_put_ci SUCCESS !");

        /*      Will implement the rest soon            */

        dprintk(verbose, DST_CA_INFO, 1, " Slot info = [%d]", slot_info[3]);
        dprintk(verbose, DST_CA_INFO, 0, "===================================\n");
        for (i = 0; i < 8; i++)
                dprintk(verbose, DST_CA_INFO, 0, " %d", slot_info[i]);
        dprintk(verbose, DST_CA_INFO, 0, "\n");

        if (slot_info[4] & 0x80) {
                p_ca_slot_info->flags = CA_CI_MODULE_PRESENT;
                p_ca_slot_info->num = 1;
                p_ca_slot_info->type = CA_CI;
        } else if (slot_info[4] & 0x40) {
                p_ca_slot_info->flags = CA_CI_MODULE_READY;
                p_ca_slot_info->num = 1;
                p_ca_slot_info->type = CA_CI;
        } else
                p_ca_slot_info->flags = 0;

        if (copy_to_user(arg, p_ca_slot_info, sizeof (struct ca_slot_info)))
                return -EFAULT;

        return 0;
}


static int ca_get_message(struct dst_state *state, struct ca_msg *p_ca_message, void __user *arg)
{
        u8 i = 0;
        u32 command = 0;

        if (copy_from_user(p_ca_message, arg, sizeof (struct ca_msg)))
                return -EFAULT;

        dprintk(verbose, DST_CA_NOTICE, 1, " Message = [%*ph]",
                3, p_ca_message->msg);

        for (i = 0; i < 3; i++) {
                command = command | p_ca_message->msg[i];
                if (i < 2)
                        command = command << 8;
        }
        dprintk(verbose, DST_CA_NOTICE, 1, " Command=[0x%x]", command);

        switch (command) {
        case CA_APP_INFO:
                memcpy(p_ca_message->msg, state->messages, 128);
                if (copy_to_user(arg, p_ca_message, sizeof (struct ca_msg)) )
                        return -EFAULT;
                break;
        case CA_INFO:
                memcpy(p_ca_message->msg, state->messages, 128);
                if (copy_to_user(arg, p_ca_message, sizeof (struct ca_msg)) )
                        return -EFAULT;
                break;
        }

        return 0;
}

static int handle_dst_tag(struct dst_state *state, struct ca_msg *p_ca_message, struct ca_msg *hw_buffer, u32 length)
{
        if (state->dst_hw_cap & DST_TYPE_HAS_SESSION) {
                hw_buffer->msg[2] = p_ca_message->msg[1];       /*      MSB     */
                hw_buffer->msg[3] = p_ca_message->msg[2];       /*      LSB     */
        } else {
                if (length > 247) {
                        dprintk(verbose, DST_CA_ERROR, 1, " Message too long ! *** Bailing Out *** !");
                        return -EIO;
                }
                hw_buffer->msg[0] = (length & 0xff) + 7;
                hw_buffer->msg[1] = 0x40;
                hw_buffer->msg[2] = 0x03;
                hw_buffer->msg[3] = 0x00;
                hw_buffer->msg[4] = 0x03;
                hw_buffer->msg[5] = length & 0xff;
                hw_buffer->msg[6] = 0x00;

                /*
                 *      Need to compute length for EN50221 section 8.3.2, for the time being
                 *      assuming 8.3.2 is not applicable
                 */
                memcpy(&hw_buffer->msg[7], &p_ca_message->msg[4], length);
        }

        return 0;
}

static int write_to_8820(struct dst_state *state, struct ca_msg *hw_buffer, u8 length, u8 reply)
{
        if ((dst_put_ci(state, hw_buffer->msg, length, hw_buffer->msg, reply)) < 0) {
                dprintk(verbose, DST_CA_ERROR, 1, " DST-CI Command failed.");
                dprintk(verbose, DST_CA_NOTICE, 1, " Resetting DST.");
                rdc_reset_state(state);
                return -EIO;
        }
        dprintk(verbose, DST_CA_NOTICE, 1, " DST-CI Command success.");

        return 0;
}

static u32 asn_1_decode(u8 *asn_1_array)
{
        u8 length_field = 0, word_count = 0, count = 0;
        u32 length = 0;

        length_field = asn_1_array[0];
        dprintk(verbose, DST_CA_DEBUG, 1, " Length field=[%02x]", length_field);
        if (length_field < 0x80) {
                length = length_field & 0x7f;
                dprintk(verbose, DST_CA_DEBUG, 1, " Length=[%02x]\n", length);
        } else {
                word_count = length_field & 0x7f;
                for (count = 0; count < word_count; count++) {
                        length = length  << 8;
                        length += asn_1_array[count + 1];
                        dprintk(verbose, DST_CA_DEBUG, 1, " Length=[%04x]", length);
                }
        }
        return length;
}

static int debug_string(u8 *msg, u32 length, u32 offset)
{
        u32 i;

        dprintk(verbose, DST_CA_DEBUG, 0, " String=[ ");
        for (i = offset; i < length; i++)
                dprintk(verbose, DST_CA_DEBUG, 0, "%02x ", msg[i]);
        dprintk(verbose, DST_CA_DEBUG, 0, "]\n");

        return 0;
}


static int ca_set_pmt(struct dst_state *state, struct ca_msg *p_ca_message, struct ca_msg *hw_buffer, u8 reply, u8 query)
{
        u32 length = 0;
        u8 tag_length = 8;

        length = asn_1_decode(&p_ca_message->msg[3]);
        dprintk(verbose, DST_CA_DEBUG, 1, " CA Message length=[%d]", length);
        debug_string(&p_ca_message->msg[4], length, 0); /*      length is excluding tag & length        */

        memset(hw_buffer->msg, '\0', length);
        handle_dst_tag(state, p_ca_message, hw_buffer, length);
        put_checksum(hw_buffer->msg, hw_buffer->msg[0]);

        debug_string(hw_buffer->msg, (length + tag_length), 0); /*      tags too        */
        write_to_8820(state, hw_buffer, (length + tag_length), reply);

        return 0;
}


/*      Board supports CA PMT reply ?           */
static int dst_check_ca_pmt(struct dst_state *state, struct ca_msg *p_ca_message, struct ca_msg *hw_buffer)
{
        int ca_pmt_reply_test = 0;

        /*      Do test board                   */
        /*      Not there yet but soon          */

        /*      CA PMT Reply capable            */
        if (ca_pmt_reply_test) {
                if ((ca_set_pmt(state, p_ca_message, hw_buffer, 1, GET_REPLY)) < 0) {
                        dprintk(verbose, DST_CA_ERROR, 1, " ca_set_pmt.. failed !");
                        return -EIO;
                }

        /*      Process CA PMT Reply            */
        /*      will implement soon             */
                dprintk(verbose, DST_CA_ERROR, 1, " Not there yet");
        }
        /*      CA PMT Reply not capable        */
        if (!ca_pmt_reply_test) {
                if ((ca_set_pmt(state, p_ca_message, hw_buffer, 0, NO_REPLY)) < 0) {
                        dprintk(verbose, DST_CA_ERROR, 1, " ca_set_pmt.. failed !");
                        return -EIO;
                }
                dprintk(verbose, DST_CA_NOTICE, 1, " ca_set_pmt.. success !");
        /*      put a dummy message             */

        }
        return 0;
}

static int ca_send_message(struct dst_state *state, struct ca_msg *p_ca_message, void __user *arg)
{
        int i;
        u32 command;
        struct ca_msg *hw_buffer;
        int result = 0;

        hw_buffer = kmalloc_obj(*hw_buffer);
        if (!hw_buffer)
                return -ENOMEM;
        dprintk(verbose, DST_CA_DEBUG, 1, " ");

        if (copy_from_user(p_ca_message, arg, sizeof (struct ca_msg))) {
                result = -EFAULT;
                goto free_mem_and_exit;
        }

        /*      EN50221 tag     */
        command = 0;

        for (i = 0; i < 3; i++) {
                command = command | p_ca_message->msg[i];
                if (i < 2)
                        command = command << 8;
        }
        dprintk(verbose, DST_CA_DEBUG, 1, " Command=[0x%x]\n", command);

        switch (command) {
        case CA_PMT:
                dprintk(verbose, DST_CA_DEBUG, 1, "Command = SEND_CA_PMT");
                if ((ca_set_pmt(state, p_ca_message, hw_buffer, 0, 0)) < 0) {   // code simplification started
                        dprintk(verbose, DST_CA_ERROR, 1, " -->CA_PMT Failed !");
                        result = -1;
                        goto free_mem_and_exit;
                }
                dprintk(verbose, DST_CA_INFO, 1, " -->CA_PMT Success !");
                break;
        case CA_PMT_REPLY:
                dprintk(verbose, DST_CA_INFO, 1, "Command = CA_PMT_REPLY");
                /*      Have to handle the 2 basic types of cards here  */
                if ((dst_check_ca_pmt(state, p_ca_message, hw_buffer)) < 0) {
                        dprintk(verbose, DST_CA_ERROR, 1, " -->CA_PMT_REPLY Failed !");
                        result = -1;
                        goto free_mem_and_exit;
                }
                dprintk(verbose, DST_CA_INFO, 1, " -->CA_PMT_REPLY Success !");
                break;
        case CA_APP_INFO_ENQUIRY:               // only for debugging
                dprintk(verbose, DST_CA_INFO, 1, " Getting Cam Application information");

                if ((ca_get_app_info(state)) < 0) {
                        dprintk(verbose, DST_CA_ERROR, 1, " -->CA_APP_INFO_ENQUIRY Failed !");
                        result = -1;
                        goto free_mem_and_exit;
                }
                dprintk(verbose, DST_CA_INFO, 1, " -->CA_APP_INFO_ENQUIRY Success !");
                break;
        case CA_INFO_ENQUIRY:
                dprintk(verbose, DST_CA_INFO, 1, " Getting CA Information");

                if ((ca_get_ca_info(state)) < 0) {
                        dprintk(verbose, DST_CA_ERROR, 1, " -->CA_INFO_ENQUIRY Failed !");
                        result = -1;
                        goto free_mem_and_exit;
                }
                dprintk(verbose, DST_CA_INFO, 1, " -->CA_INFO_ENQUIRY Success !");
                break;
        }

free_mem_and_exit:
        kfree (hw_buffer);

        return result;
}

static long dst_ca_ioctl(struct file *file, unsigned int cmd, unsigned long ioctl_arg)
{
        struct dvb_device *dvbdev;
        struct dst_state *state;
        struct ca_slot_info *p_ca_slot_info;
        struct ca_caps *p_ca_caps;
        struct ca_msg *p_ca_message;
        void __user *arg = (void __user *)ioctl_arg;
        int result = 0;

        mutex_lock(&dst_ca_mutex);
        dvbdev = file->private_data;
        state = dvbdev->priv;
        p_ca_message = kmalloc_obj(struct ca_msg);
        p_ca_slot_info = kmalloc_obj(struct ca_slot_info);
        p_ca_caps = kmalloc_obj(struct ca_caps);
        if (!p_ca_message || !p_ca_slot_info || !p_ca_caps) {
                result = -ENOMEM;
                goto free_mem_and_exit;
        }

        /*      We have now only the standard ioctl's, the driver is upposed to handle internals.       */
        switch (cmd) {
        case CA_SEND_MSG:
                dprintk(verbose, DST_CA_INFO, 1, " Sending message");
                result = ca_send_message(state, p_ca_message, arg);

                if (result < 0) {
                        dprintk(verbose, DST_CA_ERROR, 1, " -->CA_SEND_MSG Failed !");
                        goto free_mem_and_exit;
                }
                break;
        case CA_GET_MSG:
                dprintk(verbose, DST_CA_INFO, 1, " Getting message");
                result = ca_get_message(state, p_ca_message, arg);
                if (result < 0) {
                        dprintk(verbose, DST_CA_ERROR, 1, " -->CA_GET_MSG Failed !");
                        goto free_mem_and_exit;
                }
                dprintk(verbose, DST_CA_INFO, 1, " -->CA_GET_MSG Success !");
                break;
        case CA_RESET:
                dprintk(verbose, DST_CA_ERROR, 1, " Resetting DST");
                dst_error_bailout(state);
                msleep(4000);
                break;
        case CA_GET_SLOT_INFO:
                dprintk(verbose, DST_CA_INFO, 1, " Getting Slot info");
                result = ca_get_slot_info(state, p_ca_slot_info, arg);
                if (result < 0) {
                        dprintk(verbose, DST_CA_ERROR, 1, " -->CA_GET_SLOT_INFO Failed !");
                        result = -1;
                        goto free_mem_and_exit;
                }
                dprintk(verbose, DST_CA_INFO, 1, " -->CA_GET_SLOT_INFO Success !");
                break;
        case CA_GET_CAP:
                dprintk(verbose, DST_CA_INFO, 1, " Getting Slot capabilities");
                result = ca_get_slot_caps(state, p_ca_caps, arg);
                if (result < 0) {
                        dprintk(verbose, DST_CA_ERROR, 1, " -->CA_GET_CAP Failed !");
                        goto free_mem_and_exit;
                }
                dprintk(verbose, DST_CA_INFO, 1, " -->CA_GET_CAP Success !");
                break;
        case CA_GET_DESCR_INFO:
                dprintk(verbose, DST_CA_INFO, 1, " Getting descrambler description");
                result = ca_get_slot_descr(state, p_ca_message, arg);
                if (result < 0) {
                        dprintk(verbose, DST_CA_ERROR, 1, " -->CA_GET_DESCR_INFO Failed !");
                        goto free_mem_and_exit;
                }
                dprintk(verbose, DST_CA_INFO, 1, " -->CA_GET_DESCR_INFO Success !");
                break;
        default:
                result = -EOPNOTSUPP;
        }
 free_mem_and_exit:
        kfree (p_ca_message);
        kfree (p_ca_slot_info);
        kfree (p_ca_caps);

        mutex_unlock(&dst_ca_mutex);
        return result;
}

static int dst_ca_open(struct inode *inode, struct file *file)
{
        dprintk(verbose, DST_CA_DEBUG, 1, " Device opened [%p] ", file);

        return 0;
}

static int dst_ca_release(struct inode *inode, struct file *file)
{
        dprintk(verbose, DST_CA_DEBUG, 1, " Device closed.");

        return 0;
}

static ssize_t dst_ca_read(struct file *file, char __user *buffer, size_t length, loff_t *offset)
{
        dprintk(verbose, DST_CA_DEBUG, 1, " Device read.");

        return 0;
}

static ssize_t dst_ca_write(struct file *file, const char __user *buffer, size_t length, loff_t *offset)
{
        dprintk(verbose, DST_CA_DEBUG, 1, " Device write.");

        return 0;
}

static const struct file_operations dst_ca_fops = {
        .owner = THIS_MODULE,
        .unlocked_ioctl = dst_ca_ioctl,
        .open = dst_ca_open,
        .release = dst_ca_release,
        .read = dst_ca_read,
        .write = dst_ca_write,
        .llseek = noop_llseek,
};

static struct dvb_device dvbdev_ca = {
        .priv = NULL,
        .users = 1,
        .readers = 1,
        .writers = 1,
        .fops = &dst_ca_fops
};

struct dvb_device *dst_ca_attach(struct dst_state *dst, struct dvb_adapter *dvb_adapter)
{
        struct dvb_device *dvbdev;

        dprintk(verbose, DST_CA_ERROR, 1, "registering DST-CA device");
        if (dvb_register_device(dvb_adapter, &dvbdev, &dvbdev_ca, dst,
                                DVB_DEVICE_CA, 0) == 0) {
                dst->dst_ca = dvbdev;
                return dst->dst_ca;
        }

        return NULL;
}

EXPORT_SYMBOL_GPL(dst_ca_attach);

MODULE_DESCRIPTION("DST DVB-S/T/C Combo CA driver");
MODULE_AUTHOR("Manu Abraham");
MODULE_LICENSE("GPL");