drivers/media/cec/cec-api.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * cec-api.c - HDMI Consumer Electronics Control framework - API
  *
  * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
  */

 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/kmod.h>
 #include <linux/ktime.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/uaccess.h>
 #include <linux/version.h>

 #include <media/cec-pin.h>
 #include "cec-priv.h"
 #include "cec-pin-priv.h"

 static inline struct cec_devnode *cec_devnode_data(struct file *filp)
 {
 	struct cec_fh *fh = filp->private_data;

 	return &fh->adap->devnode;
 }

 /* CEC file operations */

 static __poll_t cec_poll(struct file *filp,
 			     struct poll_table_struct *poll)
 {
 	struct cec_fh *fh = filp->private_data;
 	struct cec_adapter *adap = fh->adap;
 	__poll_t res = 0;

 	if (!cec_is_registered(adap))
 		return EPOLLERR | EPOLLHUP;
 	mutex_lock(&adap->lock);
 	if (adap->is_configured &&
 	    adap->transmit_queue_sz < CEC_MAX_MSG_TX_QUEUE_SZ)
 		res |= EPOLLOUT | EPOLLWRNORM;
 	if (fh->queued_msgs)
 		res |= EPOLLIN | EPOLLRDNORM;
 	if (fh->total_queued_events)
 		res |= EPOLLPRI;
 	poll_wait(filp, &fh->wait, poll);
 	mutex_unlock(&adap->lock);
 	return res;
 }

 static bool cec_is_busy(const struct cec_adapter *adap,
 			const struct cec_fh *fh)
 {
 	bool valid_initiator = adap->cec_initiator && adap->cec_initiator == fh;
 	bool valid_follower = adap->cec_follower && adap->cec_follower == fh;

 	/*
 	 * Exclusive initiators and followers can always access the CEC adapter
 	 */
 	if (valid_initiator || valid_follower)
 		return false;
 	/*
 	 * All others can only access the CEC adapter if there is no
 	 * exclusive initiator and they are in INITIATOR mode.
 	 */
 	return adap->cec_initiator ||
 	       fh->mode_initiator == CEC_MODE_NO_INITIATOR;
 }

 static long cec_adap_g_caps(struct cec_adapter *adap,
 			    struct cec_caps __user *parg)
 {
 	struct cec_caps caps = {};

 	strlcpy(caps.driver, adap->devnode.dev.parent->driver->name,
 		sizeof(caps.driver));
 	strlcpy(caps.name, adap->name, sizeof(caps.name));
 	caps.available_log_addrs = adap->available_log_addrs;
 	caps.capabilities = adap->capabilities;
 	caps.version = LINUX_VERSION_CODE;
 	if (copy_to_user(parg, &caps, sizeof(caps)))
 		return -EFAULT;
 	return 0;
 }

 static long cec_adap_g_phys_addr(struct cec_adapter *adap,
 				 __u16 __user *parg)
 {
 	u16 phys_addr;

 	mutex_lock(&adap->lock);
 	phys_addr = adap->phys_addr;
 	mutex_unlock(&adap->lock);
 	if (copy_to_user(parg, &phys_addr, sizeof(phys_addr)))
 		return -EFAULT;
 	return 0;
 }

 static long cec_adap_s_phys_addr(struct cec_adapter *adap, struct cec_fh *fh,
 				 bool block, __u16 __user *parg)
 {
 	u16 phys_addr;
 	long err;

 	if (!(adap->capabilities & CEC_CAP_PHYS_ADDR))
 		return -ENOTTY;
 	if (copy_from_user(&phys_addr, parg, sizeof(phys_addr)))
 		return -EFAULT;

 	err = cec_phys_addr_validate(phys_addr, NULL, NULL);
 	if (err)
 		return err;
 	mutex_lock(&adap->lock);
 	if (cec_is_busy(adap, fh))
 		err = -EBUSY;
 	else
 		__cec_s_phys_addr(adap, phys_addr, block);
 	mutex_unlock(&adap->lock);
 	return err;
 }

 static long cec_adap_g_log_addrs(struct cec_adapter *adap,
 				 struct cec_log_addrs __user *parg)
 {
 	struct cec_log_addrs log_addrs;

 	mutex_lock(&adap->lock);
 	log_addrs = adap->log_addrs;
 	if (!adap->is_configured)
 		memset(log_addrs.log_addr, CEC_LOG_ADDR_INVALID,
 		       sizeof(log_addrs.log_addr));
 	mutex_unlock(&adap->lock);

 	if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
 		return -EFAULT;
 	return 0;
 }

 static long cec_adap_s_log_addrs(struct cec_adapter *adap, struct cec_fh *fh,
 				 bool block, struct cec_log_addrs __user *parg)
 {
 	struct cec_log_addrs log_addrs;
 	long err = -EBUSY;

 	if (!(adap->capabilities & CEC_CAP_LOG_ADDRS))
 		return -ENOTTY;
 	if (copy_from_user(&log_addrs, parg, sizeof(log_addrs)))
 		return -EFAULT;
 	log_addrs.flags &= CEC_LOG_ADDRS_FL_ALLOW_UNREG_FALLBACK |
 			   CEC_LOG_ADDRS_FL_ALLOW_RC_PASSTHRU |
 			   CEC_LOG_ADDRS_FL_CDC_ONLY;
 	mutex_lock(&adap->lock);
 	if (!adap->is_configuring &&
 	    (!log_addrs.num_log_addrs || !adap->is_configured) &&
 	    !cec_is_busy(adap, fh)) {
 		err = __cec_s_log_addrs(adap, &log_addrs, block);
 		if (!err)
 			log_addrs = adap->log_addrs;
 	}
 	mutex_unlock(&adap->lock);
 	if (err)
 		return err;
 	if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
 		return -EFAULT;
 	return 0;
 }

 static long cec_transmit(struct cec_adapter *adap, struct cec_fh *fh,
 			 bool block, struct cec_msg __user *parg)
 {
 	struct cec_msg msg = {};
 	long err = 0;

 	if (!(adap->capabilities & CEC_CAP_TRANSMIT))
 		return -ENOTTY;
 	if (copy_from_user(&msg, parg, sizeof(msg)))
 		return -EFAULT;

 	/* A CDC-Only device can only send CDC messages */
 	if ((adap->log_addrs.flags & CEC_LOG_ADDRS_FL_CDC_ONLY) &&
 	    (msg.len == 1 || msg.msg[1] != CEC_MSG_CDC_MESSAGE))
 		return -EINVAL;

 	mutex_lock(&adap->lock);
 	if (adap->log_addrs.num_log_addrs == 0)
 		err = -EPERM;
 	else if (adap->is_configuring)
 		err = -ENONET;
 	else if (!adap->is_configured &&
 		 (adap->needs_hpd || msg.msg[0] != 0xf0))
 		err = -ENONET;
 	else if (cec_is_busy(adap, fh))
 		err = -EBUSY;
 	else
 		err = cec_transmit_msg_fh(adap, &msg, fh, block);
 	mutex_unlock(&adap->lock);
 	if (err)
 		return err;
 	if (copy_to_user(parg, &msg, sizeof(msg)))
 		return -EFAULT;
 	return 0;
 }

 /* Called by CEC_RECEIVE: wait for a message to arrive */
 static int cec_receive_msg(struct cec_fh *fh, struct cec_msg *msg, bool block)
 {
 	u32 timeout = msg->timeout;
 	int res;

 	do {
 		mutex_lock(&fh->lock);
 		/* Are there received messages queued up? */
 		if (fh->queued_msgs) {
 			/* Yes, return the first one */
 			struct cec_msg_entry *entry =
 				list_first_entry(&fh->msgs,
 						 struct cec_msg_entry, list);

 			list_del(&entry->list);
 			*msg = entry->msg;
 			kfree(entry);
 			fh->queued_msgs--;
 			mutex_unlock(&fh->lock);
 			/* restore original timeout value */
 			msg->timeout = timeout;
 			return 0;
 		}

 		/* No, return EAGAIN in non-blocking mode or wait */
 		mutex_unlock(&fh->lock);

 		/* Return when in non-blocking mode */
 		if (!block)
 			return -EAGAIN;

 		if (msg->timeout) {
 			/* The user specified a timeout */
 			res = wait_event_interruptible_timeout(fh->wait,
 							       fh->queued_msgs,
 				msecs_to_jiffies(msg->timeout));
 			if (res == 0)
 				res = -ETIMEDOUT;
 			else if (res > 0)
 				res = 0;
 		} else {
 			/* Wait indefinitely */
 			res = wait_event_interruptible(fh->wait,
 						       fh->queued_msgs);
 		}
 		/* Exit on error, otherwise loop to get the new message */
 	} while (!res);
 	return res;
 }

 static long cec_receive(struct cec_adapter *adap, struct cec_fh *fh,
 			bool block, struct cec_msg __user *parg)
 {
 	struct cec_msg msg = {};
 	long err;

 	if (copy_from_user(&msg, parg, sizeof(msg)))
 		return -EFAULT;

 	err = cec_receive_msg(fh, &msg, block);
 	if (err)
 		return err;
 	msg.flags = 0;
 	if (copy_to_user(parg, &msg, sizeof(msg)))
 		return -EFAULT;
 	return 0;
 }

 static long cec_dqevent(struct cec_adapter *adap, struct cec_fh *fh,
 			bool block, struct cec_event __user *parg)
 {
 	struct cec_event_entry *ev = NULL;
 	u64 ts = ~0ULL;
 	unsigned int i;
 	unsigned int ev_idx;
 	long err = 0;

 	mutex_lock(&fh->lock);
 	while (!fh->total_queued_events && block) {
 		mutex_unlock(&fh->lock);
 		err = wait_event_interruptible(fh->wait,
 					       fh->total_queued_events);
 		if (err)
 			return err;
 		mutex_lock(&fh->lock);
 	}

 	/* Find the oldest event */
 	for (i = 0; i < CEC_NUM_EVENTS; i++) {
 		struct cec_event_entry *entry =
 			list_first_entry_or_null(&fh->events[i],
 						 struct cec_event_entry, list);

 		if (entry && entry->ev.ts <= ts) {
 			ev = entry;
 			ev_idx = i;
 			ts = ev->ev.ts;
 		}
 	}

 	if (!ev) {
 		err = -EAGAIN;
 		goto unlock;
 	}
 	list_del(&ev->list);

 	if (copy_to_user(parg, &ev->ev, sizeof(ev->ev)))
 		err = -EFAULT;
 	if (ev_idx >= CEC_NUM_CORE_EVENTS)
 		kfree(ev);
 	fh->queued_events[ev_idx]--;
 	fh->total_queued_events--;

 unlock:
 	mutex_unlock(&fh->lock);
 	return err;
 }

 static long cec_g_mode(struct cec_adapter *adap, struct cec_fh *fh,
 		       u32 __user *parg)
 {
 	u32 mode = fh->mode_initiator | fh->mode_follower;

 	if (copy_to_user(parg, &mode, sizeof(mode)))
 		return -EFAULT;
 	return 0;
 }

 static long cec_s_mode(struct cec_adapter *adap, struct cec_fh *fh,
 		       u32 __user *parg)
 {
 	u32 mode;
 	u8 mode_initiator;
 	u8 mode_follower;
 	bool send_pin_event = false;
 	long err = 0;

 	if (copy_from_user(&mode, parg, sizeof(mode)))
 		return -EFAULT;
 	if (mode & ~(CEC_MODE_INITIATOR_MSK | CEC_MODE_FOLLOWER_MSK)) {
 		dprintk(1, "%s: invalid mode bits set\n", __func__);
 		return -EINVAL;
 	}

 	mode_initiator = mode & CEC_MODE_INITIATOR_MSK;
 	mode_follower = mode & CEC_MODE_FOLLOWER_MSK;

 	if (mode_initiator > CEC_MODE_EXCL_INITIATOR ||
 	    mode_follower > CEC_MODE_MONITOR_ALL) {
 		dprintk(1, "%s: unknown mode\n", __func__);
 		return -EINVAL;
 	}

 	if (mode_follower == CEC_MODE_MONITOR_ALL &&
 	    !(adap->capabilities & CEC_CAP_MONITOR_ALL)) {
 		dprintk(1, "%s: MONITOR_ALL not supported\n", __func__);
 		return -EINVAL;
 	}

 	if (mode_follower == CEC_MODE_MONITOR_PIN &&
 	    !(adap->capabilities & CEC_CAP_MONITOR_PIN)) {
 		dprintk(1, "%s: MONITOR_PIN not supported\n", __func__);
 		return -EINVAL;
 	}

 	/* Follower modes should always be able to send CEC messages */
 	if ((mode_initiator == CEC_MODE_NO_INITIATOR ||
 	     !(adap->capabilities & CEC_CAP_TRANSMIT)) &&
 	    mode_follower >= CEC_MODE_FOLLOWER &&
 	    mode_follower <= CEC_MODE_EXCL_FOLLOWER_PASSTHRU) {
 		dprintk(1, "%s: cannot transmit\n", __func__);
 		return -EINVAL;
 	}

 	/* Monitor modes require CEC_MODE_NO_INITIATOR */
 	if (mode_initiator && mode_follower >= CEC_MODE_MONITOR_PIN) {
 		dprintk(1, "%s: monitor modes require NO_INITIATOR\n",
 			__func__);
 		return -EINVAL;
 	}

 	/* Monitor modes require CAP_NET_ADMIN */
 	if (mode_follower >= CEC_MODE_MONITOR_PIN && !capable(CAP_NET_ADMIN))
 		return -EPERM;

 	mutex_lock(&adap->lock);
 	/*
 	 * You can't become exclusive follower if someone else already
 	 * has that job.
 	 */
 	if ((mode_follower == CEC_MODE_EXCL_FOLLOWER ||
 	     mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) &&
 	    adap->cec_follower && adap->cec_follower != fh)
 		err = -EBUSY;
 	/*
 	 * You can't become exclusive initiator if someone else already
 	 * has that job.
 	 */
 	if (mode_initiator == CEC_MODE_EXCL_INITIATOR &&
 	    adap->cec_initiator && adap->cec_initiator != fh)
 		err = -EBUSY;

 	if (!err) {
 		bool old_mon_all = fh->mode_follower == CEC_MODE_MONITOR_ALL;
 		bool new_mon_all = mode_follower == CEC_MODE_MONITOR_ALL;

 		if (old_mon_all != new_mon_all) {
 			if (new_mon_all)
 				err = cec_monitor_all_cnt_inc(adap);
 			else
 				cec_monitor_all_cnt_dec(adap);
 		}
 	}

 	if (!err) {
 		bool old_mon_pin = fh->mode_follower == CEC_MODE_MONITOR_PIN;
 		bool new_mon_pin = mode_follower == CEC_MODE_MONITOR_PIN;

 		if (old_mon_pin != new_mon_pin) {
 			send_pin_event = new_mon_pin;
 			if (new_mon_pin)
 				err = cec_monitor_pin_cnt_inc(adap);
 			else
 				cec_monitor_pin_cnt_dec(adap);
 		}
 	}

 	if (err) {
 		mutex_unlock(&adap->lock);
 		return err;
 	}

 	if (fh->mode_follower == CEC_MODE_FOLLOWER)
 		adap->follower_cnt--;
 	if (mode_follower == CEC_MODE_FOLLOWER)
 		adap->follower_cnt++;
 	if (send_pin_event) {
 		struct cec_event ev = {
 			.flags = CEC_EVENT_FL_INITIAL_STATE,
 		};

 		ev.event = adap->cec_pin_is_high ? CEC_EVENT_PIN_CEC_HIGH :
 						   CEC_EVENT_PIN_CEC_LOW;
 		cec_queue_event_fh(fh, &ev, 0);
 	}
 	if (mode_follower == CEC_MODE_EXCL_FOLLOWER ||
 	    mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) {
 		adap->passthrough =
 			mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU;
 		adap->cec_follower = fh;
 	} else if (adap->cec_follower == fh) {
 		adap->passthrough = false;
 		adap->cec_follower = NULL;
 	}
 	if (mode_initiator == CEC_MODE_EXCL_INITIATOR)
 		adap->cec_initiator = fh;
 	else if (adap->cec_initiator == fh)
 		adap->cec_initiator = NULL;
 	fh->mode_initiator = mode_initiator;
 	fh->mode_follower = mode_follower;
 	mutex_unlock(&adap->lock);
 	return 0;
 }

 static long cec_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct cec_fh *fh = filp->private_data;
 	struct cec_adapter *adap = fh->adap;
 	bool block = !(filp->f_flags & O_NONBLOCK);
 	void __user *parg = (void __user *)arg;

 	if (!cec_is_registered(adap))
 		return -ENODEV;

 	switch (cmd) {
 	case CEC_ADAP_G_CAPS:
 		return cec_adap_g_caps(adap, parg);

 	case CEC_ADAP_G_PHYS_ADDR:
 		return cec_adap_g_phys_addr(adap, parg);

 	case CEC_ADAP_S_PHYS_ADDR:
 		return cec_adap_s_phys_addr(adap, fh, block, parg);

 	case CEC_ADAP_G_LOG_ADDRS:
 		return cec_adap_g_log_addrs(adap, parg);

 	case CEC_ADAP_S_LOG_ADDRS:
 		return cec_adap_s_log_addrs(adap, fh, block, parg);

 	case CEC_TRANSMIT:
 		return cec_transmit(adap, fh, block, parg);

 	case CEC_RECEIVE:
 		return cec_receive(adap, fh, block, parg);

 	case CEC_DQEVENT:
 		return cec_dqevent(adap, fh, block, parg);

 	case CEC_G_MODE:
 		return cec_g_mode(adap, fh, parg);

 	case CEC_S_MODE:
 		return cec_s_mode(adap, fh, parg);

 	default:
 		return -ENOTTY;
 	}
 }

 static int cec_open(struct inode *inode, struct file *filp)
 {
 	struct cec_devnode *devnode =
 		container_of(inode->i_cdev, struct cec_devnode, cdev);
 	struct cec_adapter *adap = to_cec_adapter(devnode);
 	struct cec_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
 	/*
 	 * Initial events that are automatically sent when the cec device is
 	 * opened.
 	 */
 	struct cec_event ev = {
 		.event = CEC_EVENT_STATE_CHANGE,
 		.flags = CEC_EVENT_FL_INITIAL_STATE,
 	};
 	unsigned int i;
 	int err;

 	if (!fh)
 		return -ENOMEM;

 	INIT_LIST_HEAD(&fh->msgs);
 	INIT_LIST_HEAD(&fh->xfer_list);
 	for (i = 0; i < CEC_NUM_EVENTS; i++)
 		INIT_LIST_HEAD(&fh->events[i]);
 	mutex_init(&fh->lock);
 	init_waitqueue_head(&fh->wait);

 	fh->mode_initiator = CEC_MODE_INITIATOR;
 	fh->adap = adap;

 	err = cec_get_device(devnode);
 	if (err) {
 		kfree(fh);
 		return err;
 	}

 	mutex_lock(&devnode->lock);
 	if (list_empty(&devnode->fhs) &&
 	    !adap->needs_hpd &&
 	    adap->phys_addr == CEC_PHYS_ADDR_INVALID) {
 		err = adap->ops->adap_enable(adap, true);
 		if (err) {
 			mutex_unlock(&devnode->lock);
 			kfree(fh);
 			return err;
 		}
 	}
 	filp->private_data = fh;

 	/* Queue up initial state events */
 	ev.state_change.phys_addr = adap->phys_addr;
 	ev.state_change.log_addr_mask = adap->log_addrs.log_addr_mask;
 	cec_queue_event_fh(fh, &ev, 0);
 #ifdef CONFIG_CEC_PIN
 	if (adap->pin && adap->pin->ops->read_hpd) {
 		err = adap->pin->ops->read_hpd(adap);
 		if (err >= 0) {
 			ev.event = err ? CEC_EVENT_PIN_HPD_HIGH :
 					 CEC_EVENT_PIN_HPD_LOW;
 			cec_queue_event_fh(fh, &ev, 0);
 		}
 	}
 	if (adap->pin && adap->pin->ops->read_5v) {
 		err = adap->pin->ops->read_5v(adap);
 		if (err >= 0) {
 			ev.event = err ? CEC_EVENT_PIN_5V_HIGH :
 					 CEC_EVENT_PIN_5V_LOW;
 			cec_queue_event_fh(fh, &ev, 0);
 		}
 	}
 #endif

 	list_add(&fh->list, &devnode->fhs);
 	mutex_unlock(&devnode->lock);

 	return 0;
 }

 /* Override for the release function */
 static int cec_release(struct inode *inode, struct file *filp)
 {
 	struct cec_devnode *devnode = cec_devnode_data(filp);
 	struct cec_adapter *adap = to_cec_adapter(devnode);
 	struct cec_fh *fh = filp->private_data;
 	unsigned int i;

 	mutex_lock(&adap->lock);
 	if (adap->cec_initiator == fh)
 		adap->cec_initiator = NULL;
 	if (adap->cec_follower == fh) {
 		adap->cec_follower = NULL;
 		adap->passthrough = false;
 	}
 	if (fh->mode_follower == CEC_MODE_FOLLOWER)
 		adap->follower_cnt--;
 	if (fh->mode_follower == CEC_MODE_MONITOR_PIN)
 		cec_monitor_pin_cnt_dec(adap);
 	if (fh->mode_follower == CEC_MODE_MONITOR_ALL)
 		cec_monitor_all_cnt_dec(adap);
 	mutex_unlock(&adap->lock);

 	mutex_lock(&devnode->lock);
 	list_del(&fh->list);
 	if (cec_is_registered(adap) && list_empty(&devnode->fhs) &&
 	    !adap->needs_hpd && adap->phys_addr == CEC_PHYS_ADDR_INVALID) {
 		WARN_ON(adap->ops->adap_enable(adap, false));
 	}
 	mutex_unlock(&devnode->lock);

 	/* Unhook pending transmits from this filehandle. */
 	mutex_lock(&adap->lock);
 	while (!list_empty(&fh->xfer_list)) {
 		struct cec_data *data =
 			list_first_entry(&fh->xfer_list, struct cec_data, xfer_list);

 		data->blocking = false;
 		data->fh = NULL;
 		list_del(&data->xfer_list);
 	}
 	mutex_unlock(&adap->lock);
 	while (!list_empty(&fh->msgs)) {
 		struct cec_msg_entry *entry =
 			list_first_entry(&fh->msgs, struct cec_msg_entry, list);

 		list_del(&entry->list);
 		kfree(entry);
 	}
 	for (i = CEC_NUM_CORE_EVENTS; i < CEC_NUM_EVENTS; i++) {
 		while (!list_empty(&fh->events[i])) {
 			struct cec_event_entry *entry =
 				list_first_entry(&fh->events[i],
 						 struct cec_event_entry, list);

 			list_del(&entry->list);
 			kfree(entry);
 		}
 	}
 	kfree(fh);

 	cec_put_device(devnode);
 	filp->private_data = NULL;
 	return 0;
 }

 const struct file_operations cec_devnode_fops = {
 	.owner = THIS_MODULE,
 	.open = cec_open,
 	.unlocked_ioctl = cec_ioctl,
 	.release = cec_release,
 	.poll = cec_poll,
 	.llseek = no_llseek,
 };
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* cec-api.c - HDMI Consumer Electronics Control framework - API
	*
	* Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
	*/

	#include <linux/errno.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/kmod.h>
	#include <linux/ktime.h>
	#include <linux/slab.h>
	#include <linux/mm.h>
	#include <linux/string.h>
	#include <linux/types.h>
	#include <linux/uaccess.h>
	#include <linux/version.h>

	#include <media/cec-pin.h>
	#include "cec-priv.h"
	#include "cec-pin-priv.h"

	static inline struct cec_devnode cec_devnode_data(struct file filp)
	{
	struct cec_fh *fh = filp->private_data;

	return &fh->adap->devnode;
	}

	/* CEC file operations */

	static __poll_t cec_poll(struct file *filp,
	struct poll_table_struct *poll)
	{
	struct cec_fh *fh = filp->private_data;
	struct cec_adapter *adap = fh->adap;
	__poll_t res = 0;

	if (!cec_is_registered(adap))
	return EPOLLERR \| EPOLLHUP;
	mutex_lock(&adap->lock);
	if (adap->is_configured &&
	adap->transmit_queue_sz < CEC_MAX_MSG_TX_QUEUE_SZ)
	res \|= EPOLLOUT \| EPOLLWRNORM;
	if (fh->queued_msgs)
	res \|= EPOLLIN \| EPOLLRDNORM;
	if (fh->total_queued_events)
	res \|= EPOLLPRI;
	poll_wait(filp, &fh->wait, poll);
	mutex_unlock(&adap->lock);
	return res;
	}

	static bool cec_is_busy(const struct cec_adapter *adap,
	const struct cec_fh *fh)
	{
	bool valid_initiator = adap->cec_initiator && adap->cec_initiator == fh;
	bool valid_follower = adap->cec_follower && adap->cec_follower == fh;

	/*
	* Exclusive initiators and followers can always access the CEC adapter
	*/
	if (valid_initiator \|\| valid_follower)
	return false;
	/*
	* All others can only access the CEC adapter if there is no
	* exclusive initiator and they are in INITIATOR mode.
	*/
	return adap->cec_initiator \|\|
	fh->mode_initiator == CEC_MODE_NO_INITIATOR;
	}

	static long cec_adap_g_caps(struct cec_adapter *adap,
	struct cec_caps __user *parg)
	{
	struct cec_caps caps = {};

	strlcpy(caps.driver, adap->devnode.dev.parent->driver->name,
	sizeof(caps.driver));
	strlcpy(caps.name, adap->name, sizeof(caps.name));
	caps.available_log_addrs = adap->available_log_addrs;
	caps.capabilities = adap->capabilities;
	caps.version = LINUX_VERSION_CODE;
	if (copy_to_user(parg, &caps, sizeof(caps)))
	return -EFAULT;
	return 0;
	}

	static long cec_adap_g_phys_addr(struct cec_adapter *adap,
	__u16 __user *parg)
	{
	u16 phys_addr;

	mutex_lock(&adap->lock);
	phys_addr = adap->phys_addr;
	mutex_unlock(&adap->lock);
	if (copy_to_user(parg, &phys_addr, sizeof(phys_addr)))
	return -EFAULT;
	return 0;
	}

	static long cec_adap_s_phys_addr(struct cec_adapter adap, struct cec_fh fh,
	bool block, __u16 __user *parg)
	{
	u16 phys_addr;
	long err;

	if (!(adap->capabilities & CEC_CAP_PHYS_ADDR))
	return -ENOTTY;
	if (copy_from_user(&phys_addr, parg, sizeof(phys_addr)))
	return -EFAULT;

	err = cec_phys_addr_validate(phys_addr, NULL, NULL);
	if (err)
	return err;
	mutex_lock(&adap->lock);
	if (cec_is_busy(adap, fh))
	err = -EBUSY;
	else
	__cec_s_phys_addr(adap, phys_addr, block);
	mutex_unlock(&adap->lock);
	return err;
	}

	static long cec_adap_g_log_addrs(struct cec_adapter *adap,
	struct cec_log_addrs __user *parg)
	{
	struct cec_log_addrs log_addrs;

	mutex_lock(&adap->lock);
	log_addrs = adap->log_addrs;
	if (!adap->is_configured)
	memset(log_addrs.log_addr, CEC_LOG_ADDR_INVALID,
	sizeof(log_addrs.log_addr));
	mutex_unlock(&adap->lock);

	if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
	return -EFAULT;
	return 0;
	}

	static long cec_adap_s_log_addrs(struct cec_adapter adap, struct cec_fh fh,
	bool block, struct cec_log_addrs __user *parg)
	{
	struct cec_log_addrs log_addrs;
	long err = -EBUSY;

	if (!(adap->capabilities & CEC_CAP_LOG_ADDRS))
	return -ENOTTY;
	if (copy_from_user(&log_addrs, parg, sizeof(log_addrs)))
	return -EFAULT;
	log_addrs.flags &= CEC_LOG_ADDRS_FL_ALLOW_UNREG_FALLBACK \|
	CEC_LOG_ADDRS_FL_ALLOW_RC_PASSTHRU \|
	CEC_LOG_ADDRS_FL_CDC_ONLY;
	mutex_lock(&adap->lock);
	if (!adap->is_configuring &&
	(!log_addrs.num_log_addrs \|\| !adap->is_configured) &&
	!cec_is_busy(adap, fh)) {
	err = __cec_s_log_addrs(adap, &log_addrs, block);
	if (!err)
	log_addrs = adap->log_addrs;
	}
	mutex_unlock(&adap->lock);
	if (err)
	return err;
	if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
	return -EFAULT;
	return 0;
	}

	static long cec_transmit(struct cec_adapter adap, struct cec_fh fh,
	bool block, struct cec_msg __user *parg)
	{
	struct cec_msg msg = {};
	long err = 0;

	if (!(adap->capabilities & CEC_CAP_TRANSMIT))
	return -ENOTTY;
	if (copy_from_user(&msg, parg, sizeof(msg)))
	return -EFAULT;

	/* A CDC-Only device can only send CDC messages */
	if ((adap->log_addrs.flags & CEC_LOG_ADDRS_FL_CDC_ONLY) &&
	(msg.len == 1 \|\| msg.msg[1] != CEC_MSG_CDC_MESSAGE))
	return -EINVAL;

	mutex_lock(&adap->lock);
	if (adap->log_addrs.num_log_addrs == 0)
	err = -EPERM;
	else if (adap->is_configuring)
	err = -ENONET;
	else if (!adap->is_configured &&
	(adap->needs_hpd \|\| msg.msg[0] != 0xf0))
	err = -ENONET;
	else if (cec_is_busy(adap, fh))
	err = -EBUSY;
	else
	err = cec_transmit_msg_fh(adap, &msg, fh, block);
	mutex_unlock(&adap->lock);
	if (err)
	return err;
	if (copy_to_user(parg, &msg, sizeof(msg)))
	return -EFAULT;
	return 0;
	}

	/* Called by CEC_RECEIVE: wait for a message to arrive */
	static int cec_receive_msg(struct cec_fh fh, struct cec_msg msg, bool block)
	{
	u32 timeout = msg->timeout;
	int res;

	do {
	mutex_lock(&fh->lock);
	/* Are there received messages queued up? */
	if (fh->queued_msgs) {
	/* Yes, return the first one */
	struct cec_msg_entry *entry =
	list_first_entry(&fh->msgs,
	struct cec_msg_entry, list);

	list_del(&entry->list);
	*msg = entry->msg;
	kfree(entry);
	fh->queued_msgs--;
	mutex_unlock(&fh->lock);
	/* restore original timeout value */
	msg->timeout = timeout;
	return 0;
	}

	/* No, return EAGAIN in non-blocking mode or wait */
	mutex_unlock(&fh->lock);

	/* Return when in non-blocking mode */
	if (!block)
	return -EAGAIN;

	if (msg->timeout) {
	/* The user specified a timeout */
	res = wait_event_interruptible_timeout(fh->wait,
	fh->queued_msgs,
	msecs_to_jiffies(msg->timeout));
	if (res == 0)
	res = -ETIMEDOUT;
	else if (res > 0)
	res = 0;
	} else {
	/* Wait indefinitely */
	res = wait_event_interruptible(fh->wait,
	fh->queued_msgs);
	}
	/* Exit on error, otherwise loop to get the new message */
	} while (!res);
	return res;
	}

	static long cec_receive(struct cec_adapter adap, struct cec_fh fh,
	bool block, struct cec_msg __user *parg)
	{
	struct cec_msg msg = {};
	long err;

	if (copy_from_user(&msg, parg, sizeof(msg)))
	return -EFAULT;

	err = cec_receive_msg(fh, &msg, block);
	if (err)
	return err;
	msg.flags = 0;
	if (copy_to_user(parg, &msg, sizeof(msg)))
	return -EFAULT;
	return 0;
	}

	static long cec_dqevent(struct cec_adapter adap, struct cec_fh fh,
	bool block, struct cec_event __user *parg)
	{
	struct cec_event_entry *ev = NULL;
	u64 ts = ~0ULL;
	unsigned int i;
	unsigned int ev_idx;
	long err = 0;

	mutex_lock(&fh->lock);
	while (!fh->total_queued_events && block) {
	mutex_unlock(&fh->lock);
	err = wait_event_interruptible(fh->wait,
	fh->total_queued_events);
	if (err)
	return err;
	mutex_lock(&fh->lock);
	}

	/* Find the oldest event */
	for (i = 0; i < CEC_NUM_EVENTS; i++) {
	struct cec_event_entry *entry =
	list_first_entry_or_null(&fh->events[i],
	struct cec_event_entry, list);

	if (entry && entry->ev.ts <= ts) {
	ev = entry;
	ev_idx = i;
	ts = ev->ev.ts;
	}
	}

	if (!ev) {
	err = -EAGAIN;
	goto unlock;
	}
	list_del(&ev->list);

	if (copy_to_user(parg, &ev->ev, sizeof(ev->ev)))
	err = -EFAULT;
	if (ev_idx >= CEC_NUM_CORE_EVENTS)
	kfree(ev);
	fh->queued_events[ev_idx]--;
	fh->total_queued_events--;

	unlock:
	mutex_unlock(&fh->lock);
	return err;
	}

	static long cec_g_mode(struct cec_adapter adap, struct cec_fh fh,
	u32 __user *parg)
	{
	u32 mode = fh->mode_initiator \| fh->mode_follower;

	if (copy_to_user(parg, &mode, sizeof(mode)))
	return -EFAULT;
	return 0;
	}

	static long cec_s_mode(struct cec_adapter adap, struct cec_fh fh,
	u32 __user *parg)
	{
	u32 mode;
	u8 mode_initiator;
	u8 mode_follower;
	bool send_pin_event = false;
	long err = 0;

	if (copy_from_user(&mode, parg, sizeof(mode)))
	return -EFAULT;
	if (mode & ~(CEC_MODE_INITIATOR_MSK \| CEC_MODE_FOLLOWER_MSK)) {
	dprintk(1, "%s: invalid mode bits set\n", __func__);
	return -EINVAL;
	}

	mode_initiator = mode & CEC_MODE_INITIATOR_MSK;
	mode_follower = mode & CEC_MODE_FOLLOWER_MSK;

	if (mode_initiator > CEC_MODE_EXCL_INITIATOR \|\|
	mode_follower > CEC_MODE_MONITOR_ALL) {
	dprintk(1, "%s: unknown mode\n", __func__);
	return -EINVAL;
	}

	if (mode_follower == CEC_MODE_MONITOR_ALL &&
	!(adap->capabilities & CEC_CAP_MONITOR_ALL)) {
	dprintk(1, "%s: MONITOR_ALL not supported\n", __func__);
	return -EINVAL;
	}

	if (mode_follower == CEC_MODE_MONITOR_PIN &&
	!(adap->capabilities & CEC_CAP_MONITOR_PIN)) {
	dprintk(1, "%s: MONITOR_PIN not supported\n", __func__);
	return -EINVAL;
	}

	/* Follower modes should always be able to send CEC messages */
	if ((mode_initiator == CEC_MODE_NO_INITIATOR \|\|
	!(adap->capabilities & CEC_CAP_TRANSMIT)) &&
	mode_follower >= CEC_MODE_FOLLOWER &&
	mode_follower <= CEC_MODE_EXCL_FOLLOWER_PASSTHRU) {
	dprintk(1, "%s: cannot transmit\n", __func__);
	return -EINVAL;
	}

	/* Monitor modes require CEC_MODE_NO_INITIATOR */
	if (mode_initiator && mode_follower >= CEC_MODE_MONITOR_PIN) {
	dprintk(1, "%s: monitor modes require NO_INITIATOR\n",
	__func__);
	return -EINVAL;
	}

	/* Monitor modes require CAP_NET_ADMIN */
	if (mode_follower >= CEC_MODE_MONITOR_PIN && !capable(CAP_NET_ADMIN))
	return -EPERM;

	mutex_lock(&adap->lock);
	/*
	* You can't become exclusive follower if someone else already
	* has that job.
	*/
	if ((mode_follower == CEC_MODE_EXCL_FOLLOWER \|\|
	mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) &&
	adap->cec_follower && adap->cec_follower != fh)
	err = -EBUSY;
	/*
	* You can't become exclusive initiator if someone else already
	* has that job.
	*/
	if (mode_initiator == CEC_MODE_EXCL_INITIATOR &&
	adap->cec_initiator && adap->cec_initiator != fh)
	err = -EBUSY;

	if (!err) {
	bool old_mon_all = fh->mode_follower == CEC_MODE_MONITOR_ALL;
	bool new_mon_all = mode_follower == CEC_MODE_MONITOR_ALL;

	if (old_mon_all != new_mon_all) {
	if (new_mon_all)
	err = cec_monitor_all_cnt_inc(adap);
	else
	cec_monitor_all_cnt_dec(adap);
	}
	}

	if (!err) {
	bool old_mon_pin = fh->mode_follower == CEC_MODE_MONITOR_PIN;
	bool new_mon_pin = mode_follower == CEC_MODE_MONITOR_PIN;

	if (old_mon_pin != new_mon_pin) {
	send_pin_event = new_mon_pin;
	if (new_mon_pin)
	err = cec_monitor_pin_cnt_inc(adap);
	else
	cec_monitor_pin_cnt_dec(adap);
	}
	}

	if (err) {
	mutex_unlock(&adap->lock);
	return err;
	}

	if (fh->mode_follower == CEC_MODE_FOLLOWER)
	adap->follower_cnt--;
	if (mode_follower == CEC_MODE_FOLLOWER)
	adap->follower_cnt++;
	if (send_pin_event) {
	struct cec_event ev = {
	.flags = CEC_EVENT_FL_INITIAL_STATE,
	};

	ev.event = adap->cec_pin_is_high ? CEC_EVENT_PIN_CEC_HIGH :
	CEC_EVENT_PIN_CEC_LOW;
	cec_queue_event_fh(fh, &ev, 0);
	}
	if (mode_follower == CEC_MODE_EXCL_FOLLOWER \|\|
	mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) {
	adap->passthrough =
	mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU;
	adap->cec_follower = fh;
	} else if (adap->cec_follower == fh) {
	adap->passthrough = false;
	adap->cec_follower = NULL;
	}
	if (mode_initiator == CEC_MODE_EXCL_INITIATOR)
	adap->cec_initiator = fh;
	else if (adap->cec_initiator == fh)
	adap->cec_initiator = NULL;
	fh->mode_initiator = mode_initiator;
	fh->mode_follower = mode_follower;
	mutex_unlock(&adap->lock);
	return 0;
	}

	static long cec_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
	{
	struct cec_fh *fh = filp->private_data;
	struct cec_adapter *adap = fh->adap;
	bool block = !(filp->f_flags & O_NONBLOCK);
	void __user parg = (void __user )arg;

	if (!cec_is_registered(adap))
	return -ENODEV;

	switch (cmd) {
	case CEC_ADAP_G_CAPS:
	return cec_adap_g_caps(adap, parg);

	case CEC_ADAP_G_PHYS_ADDR:
	return cec_adap_g_phys_addr(adap, parg);

	case CEC_ADAP_S_PHYS_ADDR:
	return cec_adap_s_phys_addr(adap, fh, block, parg);

	case CEC_ADAP_G_LOG_ADDRS:
	return cec_adap_g_log_addrs(adap, parg);

	case CEC_ADAP_S_LOG_ADDRS:
	return cec_adap_s_log_addrs(adap, fh, block, parg);

	case CEC_TRANSMIT:
	return cec_transmit(adap, fh, block, parg);

	case CEC_RECEIVE:
	return cec_receive(adap, fh, block, parg);

	case CEC_DQEVENT:
	return cec_dqevent(adap, fh, block, parg);

	case CEC_G_MODE:
	return cec_g_mode(adap, fh, parg);

	case CEC_S_MODE:
	return cec_s_mode(adap, fh, parg);

	default:
	return -ENOTTY;
	}
	}

	static int cec_open(struct inode inode, struct file filp)
	{
	struct cec_devnode *devnode =
	container_of(inode->i_cdev, struct cec_devnode, cdev);
	struct cec_adapter *adap = to_cec_adapter(devnode);
	struct cec_fh fh = kzalloc(sizeof(fh), GFP_KERNEL);
	/*
	* Initial events that are automatically sent when the cec device is
	* opened.
	*/
	struct cec_event ev = {
	.event = CEC_EVENT_STATE_CHANGE,
	.flags = CEC_EVENT_FL_INITIAL_STATE,
	};
	unsigned int i;
	int err;

	if (!fh)
	return -ENOMEM;

	INIT_LIST_HEAD(&fh->msgs);
	INIT_LIST_HEAD(&fh->xfer_list);
	for (i = 0; i < CEC_NUM_EVENTS; i++)
	INIT_LIST_HEAD(&fh->events[i]);
	mutex_init(&fh->lock);
	init_waitqueue_head(&fh->wait);

	fh->mode_initiator = CEC_MODE_INITIATOR;
	fh->adap = adap;

	err = cec_get_device(devnode);
	if (err) {
	kfree(fh);
	return err;
	}

	mutex_lock(&devnode->lock);
	if (list_empty(&devnode->fhs) &&
	!adap->needs_hpd &&
	adap->phys_addr == CEC_PHYS_ADDR_INVALID) {
	err = adap->ops->adap_enable(adap, true);
	if (err) {
	mutex_unlock(&devnode->lock);
	kfree(fh);
	return err;
	}
	}
	filp->private_data = fh;

	/* Queue up initial state events */
	ev.state_change.phys_addr = adap->phys_addr;
	ev.state_change.log_addr_mask = adap->log_addrs.log_addr_mask;
	cec_queue_event_fh(fh, &ev, 0);
	#ifdef CONFIG_CEC_PIN
	if (adap->pin && adap->pin->ops->read_hpd) {
	err = adap->pin->ops->read_hpd(adap);
	if (err >= 0) {
	ev.event = err ? CEC_EVENT_PIN_HPD_HIGH :
	CEC_EVENT_PIN_HPD_LOW;
	cec_queue_event_fh(fh, &ev, 0);
	}
	}
	if (adap->pin && adap->pin->ops->read_5v) {
	err = adap->pin->ops->read_5v(adap);
	if (err >= 0) {
	ev.event = err ? CEC_EVENT_PIN_5V_HIGH :
	CEC_EVENT_PIN_5V_LOW;
	cec_queue_event_fh(fh, &ev, 0);
	}
	}
	#endif

	list_add(&fh->list, &devnode->fhs);
	mutex_unlock(&devnode->lock);

	return 0;
	}

	/* Override for the release function */
	static int cec_release(struct inode inode, struct file filp)
	{
	struct cec_devnode *devnode = cec_devnode_data(filp);
	struct cec_adapter *adap = to_cec_adapter(devnode);
	struct cec_fh *fh = filp->private_data;
	unsigned int i;

	mutex_lock(&adap->lock);
	if (adap->cec_initiator == fh)
	adap->cec_initiator = NULL;
	if (adap->cec_follower == fh) {
	adap->cec_follower = NULL;
	adap->passthrough = false;
	}
	if (fh->mode_follower == CEC_MODE_FOLLOWER)
	adap->follower_cnt--;
	if (fh->mode_follower == CEC_MODE_MONITOR_PIN)
	cec_monitor_pin_cnt_dec(adap);
	if (fh->mode_follower == CEC_MODE_MONITOR_ALL)
	cec_monitor_all_cnt_dec(adap);
	mutex_unlock(&adap->lock);

	mutex_lock(&devnode->lock);
	list_del(&fh->list);
	if (cec_is_registered(adap) && list_empty(&devnode->fhs) &&
	!adap->needs_hpd && adap->phys_addr == CEC_PHYS_ADDR_INVALID) {
	WARN_ON(adap->ops->adap_enable(adap, false));
	}
	mutex_unlock(&devnode->lock);

	/* Unhook pending transmits from this filehandle. */
	mutex_lock(&adap->lock);
	while (!list_empty(&fh->xfer_list)) {
	struct cec_data *data =
	list_first_entry(&fh->xfer_list, struct cec_data, xfer_list);

	data->blocking = false;
	data->fh = NULL;
	list_del(&data->xfer_list);
	}
	mutex_unlock(&adap->lock);
	while (!list_empty(&fh->msgs)) {
	struct cec_msg_entry *entry =
	list_first_entry(&fh->msgs, struct cec_msg_entry, list);

	list_del(&entry->list);
	kfree(entry);
	}
	for (i = CEC_NUM_CORE_EVENTS; i < CEC_NUM_EVENTS; i++) {
	while (!list_empty(&fh->events[i])) {
	struct cec_event_entry *entry =
	list_first_entry(&fh->events[i],
	struct cec_event_entry, list);

	list_del(&entry->list);
	kfree(entry);
	}
	}
	kfree(fh);

	cec_put_device(devnode);
	filp->private_data = NULL;
	return 0;
	}

	const struct file_operations cec_devnode_fops = {
	.owner = THIS_MODULE,
	.open = cec_open,
	.unlocked_ioctl = cec_ioctl,
	.release = cec_release,
	.poll = cec_poll,
	.llseek = no_llseek,
	};