cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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vivid-radio-tx.c (3630B)

      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->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
     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 *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
    118int 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}