vivid-radio-tx.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * vivid-radio-tx.c - radio transmitter support functions.
  4 *
  5 * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
  6 */
  7
  8#include <linux/errno.h>
  9#include <linux/kernel.h>
 10#include <linux/sched/signal.h>
 11#include <linux/delay.h>
 12#include <linux/videodev2.h>
 13#include <linux/v4l2-dv-timings.h>
 14#include <media/v4l2-common.h>
 15#include <media/v4l2-event.h>
 16#include <media/v4l2-dv-timings.h>
 17
 18#include "vivid-core.h"
 19#include "vivid-ctrls.h"
 20#include "vivid-radio-common.h"
 21#include "vivid-radio-tx.h"
 22
 23ssize_t vivid_radio_tx_write(struct file *file, const char __user *buf,
 24			  size_t size, loff_t *offset)
 25{
 26	struct vivid_dev *dev = video_drvdata(file);
 27	struct v4l2_rds_data *data = dev->rds_gen.data;
 28	ktime_t timestamp;
 29	unsigned blk;
 30	int i;
 31
 32	if (dev->radio_tx_rds_controls)
 33		return -EINVAL;
 34
 35	if (size < sizeof(*data))
 36		return -EINVAL;
 37	size = sizeof(*data) * (size / sizeof(*data));
 38
 39	if (mutex_lock_interruptible(&dev->mutex))
 40		return -ERESTARTSYS;
 41	if (dev->radio_tx_rds_owner &&
 42	    file_to_v4l2_fh(file) != dev->radio_tx_rds_owner) {
 43		mutex_unlock(&dev->mutex);
 44		return -EBUSY;
 45	}
 46	dev->radio_tx_rds_owner = file_to_v4l2_fh(file);
 47
 48retry:
 49	timestamp = ktime_sub(ktime_get(), dev->radio_rds_init_time);
 50	blk = ktime_divns(timestamp, VIVID_RDS_NSEC_PER_BLK);
 51	if (blk - VIVID_RDS_GEN_BLOCKS >= dev->radio_tx_rds_last_block)
 52		dev->radio_tx_rds_last_block = blk - VIVID_RDS_GEN_BLOCKS + 1;
 53
 54	/*
 55	 * No data is available if there hasn't been time to get new data,
 56	 * or if the RDS receiver has been disabled, or if we use the data
 57	 * from the RDS transmitter and that RDS transmitter has been disabled,
 58	 * or if the signal quality is too weak.
 59	 */
 60	if (blk == dev->radio_tx_rds_last_block ||
 61	    !(dev->radio_tx_subchans & V4L2_TUNER_SUB_RDS)) {
 62		mutex_unlock(&dev->mutex);
 63		if (file->f_flags & O_NONBLOCK)
 64			return -EWOULDBLOCK;
 65		if (msleep_interruptible(20) && signal_pending(current))
 66			return -EINTR;
 67		if (mutex_lock_interruptible(&dev->mutex))
 68			return -ERESTARTSYS;
 69		goto retry;
 70	}
 71
 72	for (i = 0; i < size && blk > dev->radio_tx_rds_last_block;
 73			dev->radio_tx_rds_last_block++) {
 74		unsigned data_blk = dev->radio_tx_rds_last_block % VIVID_RDS_GEN_BLOCKS;
 75		struct v4l2_rds_data rds;
 76
 77		if (copy_from_user(&rds, buf + i, sizeof(rds))) {
 78			i = -EFAULT;
 79			break;
 80		}
 81		i += sizeof(rds);
 82		if (!dev->radio_rds_loop)
 83			continue;
 84		if ((rds.block & V4L2_RDS_BLOCK_MSK) == V4L2_RDS_BLOCK_INVALID ||
 85		    (rds.block & V4L2_RDS_BLOCK_ERROR))
 86			continue;
 87		rds.block &= V4L2_RDS_BLOCK_MSK;
 88		data[data_blk] = rds;
 89	}
 90	mutex_unlock(&dev->mutex);
 91	return i;
 92}
 93
 94__poll_t vivid_radio_tx_poll(struct file *file, struct poll_table_struct *wait)
 95{
 96	return EPOLLOUT | EPOLLWRNORM | v4l2_ctrl_poll(file, wait);
 97}
 98
 99int vidioc_g_modulator(struct file *file, void *priv, struct v4l2_modulator *a)
100{
101	struct vivid_dev *dev = video_drvdata(file);
102
103	if (a->index > 0)
104		return -EINVAL;
105
106	strscpy(a->name, "AM/FM/SW Transmitter", sizeof(a->name));
107	a->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
108			V4L2_TUNER_CAP_FREQ_BANDS | V4L2_TUNER_CAP_RDS |
109			(dev->radio_tx_rds_controls ?
110				V4L2_TUNER_CAP_RDS_CONTROLS :
111				V4L2_TUNER_CAP_RDS_BLOCK_IO);
112	a->rangelow = AM_FREQ_RANGE_LOW;
113	a->rangehigh = FM_FREQ_RANGE_HIGH;
114	a->txsubchans = dev->radio_tx_subchans;
115	return 0;
116}
117
118int vidioc_s_modulator(struct file *file, void *priv, const struct v4l2_modulator *a)
119{
120	struct vivid_dev *dev = video_drvdata(file);
121
122	if (a->index)
123		return -EINVAL;
124	if (a->txsubchans & ~0x13)
125		return -EINVAL;
126	dev->radio_tx_subchans = a->txsubchans;
127	return 0;
128}