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 
vivid_radio_tx_write(struct file * file,const char __user * buf,size_t size,loff_t * offset)23 ssize_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->private_data != dev->radio_tx_rds_owner) {
43 		mutex_unlock(&dev->mutex);
44 		return -EBUSY;
45 	}
46 	dev->radio_tx_rds_owner = file->private_data;
47 
48 retry:
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 
vivid_radio_tx_poll(struct file * file,struct poll_table_struct * wait)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 
vidioc_g_modulator(struct file * file,void * fh,struct v4l2_modulator * a)99 int vidioc_g_modulator(struct file *file, void *fh, 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 
vidioc_s_modulator(struct file * file,void * fh,const struct v4l2_modulator * a)118 int vidioc_s_modulator(struct file *file, void *fh, 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 }
129