// SPDX-License-Identifier: GPL-2.0-only
/*
 * vivid-radio-tx.c - radio transmitter support functions.
 *
 * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/delay.h>
#include <linux/videodev2.h>
#include <linux/v4l2-dv-timings.h>
#include <media/v4l2-common.h>
#include <media/v4l2-event.h>
#include <media/v4l2-dv-timings.h>

#include "vivid-core.h"
#include "vivid-ctrls.h"
#include "vivid-radio-common.h"
#include "vivid-radio-tx.h"

ssize_t vivid_radio_tx_write(struct file *file, const char __user *buf,
                          size_t size, loff_t *offset)
{
        struct vivid_dev *dev = video_drvdata(file);
        struct v4l2_rds_data *data = dev->rds_gen.data;
        ktime_t timestamp;
        unsigned blk;
        int i;

        if (dev->radio_tx_rds_controls)
                return -EINVAL;

        if (size < sizeof(*data))
                return -EINVAL;
        size = sizeof(*data) * (size / sizeof(*data));

        if (mutex_lock_interruptible(&dev->mutex))
                return -ERESTARTSYS;
        if (dev->radio_tx_rds_owner &&
            file_to_v4l2_fh(file) != dev->radio_tx_rds_owner) {
                mutex_unlock(&dev->mutex);
                return -EBUSY;
        }
        dev->radio_tx_rds_owner = file_to_v4l2_fh(file);

retry:
        timestamp = ktime_sub(ktime_get(), dev->radio_rds_init_time);
        blk = ktime_divns(timestamp, VIVID_RDS_NSEC_PER_BLK);
        if (blk - VIVID_RDS_GEN_BLOCKS >= dev->radio_tx_rds_last_block)
                dev->radio_tx_rds_last_block = blk - VIVID_RDS_GEN_BLOCKS + 1;

        /*
         * No data is available if there hasn't been time to get new data,
         * or if the RDS receiver has been disabled, or if we use the data
         * from the RDS transmitter and that RDS transmitter has been disabled,
         * or if the signal quality is too weak.
         */
        if (blk == dev->radio_tx_rds_last_block ||
            !(dev->radio_tx_subchans & V4L2_TUNER_SUB_RDS)) {
                mutex_unlock(&dev->mutex);
                if (file->f_flags & O_NONBLOCK)
                        return -EWOULDBLOCK;
                if (msleep_interruptible(20) && signal_pending(current))
                        return -EINTR;
                if (mutex_lock_interruptible(&dev->mutex))
                        return -ERESTARTSYS;
                goto retry;
        }

        for (i = 0; i < size && blk > dev->radio_tx_rds_last_block;
                        dev->radio_tx_rds_last_block++) {
                unsigned data_blk = dev->radio_tx_rds_last_block % VIVID_RDS_GEN_BLOCKS;
                struct v4l2_rds_data rds;

                if (copy_from_user(&rds, buf + i, sizeof(rds))) {
                        i = -EFAULT;
                        break;
                }
                i += sizeof(rds);
                if (!dev->radio_rds_loop)
                        continue;
                if ((rds.block & V4L2_RDS_BLOCK_MSK) == V4L2_RDS_BLOCK_INVALID ||
                    (rds.block & V4L2_RDS_BLOCK_ERROR))
                        continue;
                rds.block &= V4L2_RDS_BLOCK_MSK;
                data[data_blk] = rds;
        }
        mutex_unlock(&dev->mutex);
        return i;
}

__poll_t vivid_radio_tx_poll(struct file *file, struct poll_table_struct *wait)
{
        return EPOLLOUT | EPOLLWRNORM | v4l2_ctrl_poll(file, wait);
}

int vidioc_g_modulator(struct file *file, void *priv, struct v4l2_modulator *a)
{
        struct vivid_dev *dev = video_drvdata(file);

        if (a->index > 0)
                return -EINVAL;

        strscpy(a->name, "AM/FM/SW Transmitter", sizeof(a->name));
        a->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
                        V4L2_TUNER_CAP_FREQ_BANDS | V4L2_TUNER_CAP_RDS |
                        (dev->radio_tx_rds_controls ?
                                V4L2_TUNER_CAP_RDS_CONTROLS :
                                V4L2_TUNER_CAP_RDS_BLOCK_IO);
        a->rangelow = AM_FREQ_RANGE_LOW;
        a->rangehigh = FM_FREQ_RANGE_HIGH;
        a->txsubchans = dev->radio_tx_subchans;
        return 0;
}

int vidioc_s_modulator(struct file *file, void *priv, const struct v4l2_modulator *a)
{
        struct vivid_dev *dev = video_drvdata(file);

        if (a->index)
                return -EINVAL;
        if (a->txsubchans & ~0x13)
                return -EINVAL;
        dev->radio_tx_subchans = a->txsubchans;
        return 0;
}