[media] cec: add HDMI CEC framework (api)

The added HDMI CEC framework provides a generic kernel interface for
HDMI CEC devices.

Note that the CEC framework is added to staging/media and that the
cec.h and cec-funcs.h headers are not exported yet. While the kABI
is mature, I would prefer to allow the uABI some more time before
it is mainlined in case it needs more tweaks.

This adds the cec-api.c source that deals with the public CEC API
and the Kconfig/Makefile plumbing.

The MAINTAINERS file is also updated.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
[k.debski@samsung.com: code cleanup and fixes]
Signed-off-by: Kamil Debski <kamil@wypas.org>

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

MAINTAINERS

@@ -2847,6 +2847,22 @@ F:	drivers/net/ieee802154/cc2520.c
 F:	include/linux/spi/cc2520.h
 F:	Documentation/devicetree/bindings/net/ieee802154/cc2520.txt
 
+CEC DRIVER
+M:	Hans Verkuil <hans.verkuil@cisco.com>
+L:	linux-media@vger.kernel.org
+T:	git git://linuxtv.org/media_tree.git
+W:	http://linuxtv.org
+S:	Supported
+F:	Documentation/cec.txt
+F:	Documentation/DocBook/media/v4l/cec*
+F:	drivers/staging/media/cec/
+F:	drivers/media/cec-edid.c
+F:	drivers/media/rc/keymaps/rc-cec.c
+F:	include/media/cec.h
+F:	include/media/cec-edid.h
+F:	include/linux/cec.h
+F:	include/linux/cec-funcs.h
+
 CELL BROADBAND ENGINE ARCHITECTURE
 M:	Arnd Bergmann <arnd@arndb.de>
 L:	linuxppc-dev@lists.ozlabs.org

drivers/staging/media/Kconfig

@@ -21,6 +21,8 @@ if STAGING_MEDIA
 # Please keep them in alphabetic order
 source "drivers/staging/media/bcm2048/Kconfig"
 
+source "drivers/staging/media/cec/Kconfig"
+
 source "drivers/staging/media/cxd2099/Kconfig"
 
 source "drivers/staging/media/davinci_vpfe/Kconfig"

drivers/staging/media/Makefile

@@ -1,4 +1,5 @@
 obj-$(CONFIG_I2C_BCM2048)	+= bcm2048/
+obj-$(CONFIG_MEDIA_CEC)		+= cec/
 obj-$(CONFIG_DVB_CXD2099)	+= cxd2099/
 obj-$(CONFIG_LIRC_STAGING)	+= lirc/
 obj-$(CONFIG_VIDEO_DM365_VPFE)	+= davinci_vpfe/

drivers/staging/media/cec/Kconfig

@@ -0,0 +1,14 @@
+config MEDIA_CEC
+	tristate "CEC API (EXPERIMENTAL)"
+	select MEDIA_CEC_EDID
+	---help---
+	  Enable the CEC API.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cec.
+
+config MEDIA_CEC_DEBUG
+	bool "CEC debugfs interface (EXPERIMENTAL)"
+	depends on MEDIA_CEC && DEBUG_FS
+	---help---
+	  Turns on the DebugFS interface for CEC devices.

drivers/staging/media/cec/Makefile

@@ -0,0 +1,3 @@
+cec-objs := cec-core.o cec-adap.o cec-api.o
+
+obj-$(CONFIG_MEDIA_CEC) += cec.o

drivers/staging/media/cec/cec-api.c

@@ -0,0 +1,578 @@
+/*
+ * cec-api.c - HDMI Consumer Electronics Control framework - API
+ *
+ * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#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 "cec-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 unsigned int cec_poll(struct file *filp,
+			     struct poll_table_struct *poll)
+{
+	struct cec_devnode *devnode = cec_devnode_data(filp);
+	struct cec_fh *fh = filp->private_data;
+	struct cec_adapter *adap = fh->adap;
+	unsigned int res = 0;
+
+	if (!devnode->registered)
+		return POLLERR | POLLHUP;
+	mutex_lock(&adap->lock);
+	if (adap->is_configured)
+		res |= POLLOUT | POLLWRNORM;
+	if (fh->queued_msgs)
+		res |= POLLIN | POLLRDNORM;
+	if (fh->pending_events)
+		res |= POLLPRI;
+	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.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 = 0;
+	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;
+	mutex_lock(&adap->lock);
+	if (!adap->is_configured) {
+		err = -ENONET;
+	} else if (cec_is_busy(adap, fh)) {
+		err = -EBUSY;
+	} else {
+		if (!block || !msg.reply)
+			fh = NULL;
+		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)
+{
+	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);
+			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 = 0;
+
+	if (copy_from_user(&msg, parg, sizeof(msg)))
+		return -EFAULT;
+	mutex_lock(&adap->lock);
+	if (!adap->is_configured)
+		err = -ENONET;
+	mutex_unlock(&adap->lock);
+	if (err)
+		return err;
+
+	err = cec_receive_msg(fh, &msg, block);
+	if (err)
+		return err;
+	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 *ev = NULL;
+	u64 ts = ~0ULL;
+	unsigned int i;
+	long err = 0;
+
+	mutex_lock(&fh->lock);
+	while (!fh->pending_events && block) {
+		mutex_unlock(&fh->lock);
+		err = wait_event_interruptible(fh->wait, fh->pending_events);
+		if (err)
+			return err;
+		mutex_lock(&fh->lock);
+	}
+
+	/* Find the oldest event */
+	for (i = 0; i < CEC_NUM_EVENTS; i++) {
+		if (fh->pending_events & (1 << (i + 1)) &&
+		    fh->events[i].ts <= ts) {
+			ev = &fh->events[i];
+			ts = ev->ts;
+		}
+	}
+	if (!ev) {
+		err = -EAGAIN;
+		goto unlock;
+	}
+
+	if (copy_to_user(parg, ev, sizeof(*ev))) {
+		err = -EFAULT;
+		goto unlock;
+	}
+
+	fh->pending_events &= ~(1 << ev->event);
+
+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;
+	long err = 0;
+
+	if (copy_from_user(&mode, parg, sizeof(mode)))
+		return -EFAULT;
+	if (mode & ~(CEC_MODE_INITIATOR_MSK | CEC_MODE_FOLLOWER_MSK))
+		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)
+		return -EINVAL;
+
+	if (mode_follower == CEC_MODE_MONITOR_ALL &&
+	    !(adap->capabilities & CEC_CAP_MONITOR_ALL))
+		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)
+		return -EINVAL;
+
+	/* Monitor modes require CEC_MODE_NO_INITIATOR */
+	if (mode_initiator && mode_follower >= CEC_MODE_MONITOR)
+		return -EINVAL;
+
+	/* Monitor modes require CAP_NET_ADMIN */
+	if (mode_follower >= CEC_MODE_MONITOR && !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) {
+		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 (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_devnode *devnode = cec_devnode_data(filp);
+	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 (!devnode->registered)
+		return -EIO;
+
+	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_state = {
+		.event = CEC_EVENT_STATE_CHANGE,
+		.flags = CEC_EVENT_FL_INITIAL_STATE,
+	};
+	int err;
+
+	if (!fh)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&fh->msgs);
+	INIT_LIST_HEAD(&fh->xfer_list);
+	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;
+	}
+
+	filp->private_data = fh;
+
+	mutex_lock(&devnode->fhs_lock);
+	/* Queue up initial state events */
+	ev_state.state_change.phys_addr = adap->phys_addr;
+	ev_state.state_change.log_addr_mask = adap->log_addrs.log_addr_mask;
+	cec_queue_event_fh(fh, &ev_state, 0);
+
+	list_add(&fh->list, &devnode->fhs);
+	mutex_unlock(&devnode->fhs_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;
+
+	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_ALL)
+		cec_monitor_all_cnt_dec(adap);
+	mutex_unlock(&adap->lock);
+
+	mutex_lock(&devnode->fhs_lock);
+	list_del(&fh->list);
+	mutex_unlock(&devnode->fhs_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);
+	}
+	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,
+};