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

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-core.c, media/cec.h and cec-priv.h sources.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
[k.debski@samsung.com: Merged CEC Updates commit by Hans Verkuil]
[k.debski@samsung.com: Merged Update author commit by Hans Verkuil]
[k.debski@samsung.com: code cleanup and fixes]
[k.debski@samsung.com: add missing CEC commands to match spec]
[k.debski@samsung.com: add RC framework support]
[k.debski@samsung.com: move and edit documentation]
[k.debski@samsung.com: add vendor id reporting]
[k.debski@samsung.com: reorder of API structs and add reserved fields]
[k.debski@samsung.com: fix handling of events and fix 32/64bit timespec problem]
[k.debski@samsung.com: add sequence number handling]
[k.debski@samsung.com: add passthrough mode]
[k.debski@samsung.com: fix CEC defines, add missing CEC 2.0 commands]
Signed-off-by: Kamil Debski <kamil@wypas.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/staging/media/cec/cec-priv.h

+/*
+ * cec-priv.h - HDMI Consumer Electronics Control internal header
+ *
+ * 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.
+ */
+
+#ifndef _CEC_PRIV_H
+#define _CEC_PRIV_H
+
+#include <linux/cec-funcs.h>
+#include <media/cec.h>
+
+#define dprintk(lvl, fmt, arg...)					\
+	do {								\
+		if (lvl <= cec_debug)					\
+			pr_info("cec-%s: " fmt, adap->name, ## arg);	\
+	} while (0)
+
+/* devnode to cec_adapter */
+#define to_cec_adapter(node) container_of(node, struct cec_adapter, devnode)
+
+/* cec-core.c */
+extern int cec_debug;
+int cec_get_device(struct cec_devnode *devnode);
+void cec_put_device(struct cec_devnode *devnode);
+
+/* cec-adap.c */
+int cec_monitor_all_cnt_inc(struct cec_adapter *adap);
+void cec_monitor_all_cnt_dec(struct cec_adapter *adap);
+int cec_adap_status(struct seq_file *file, void *priv);
+int cec_thread_func(void *_adap);
+void __cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr, bool block);
+int __cec_s_log_addrs(struct cec_adapter *adap,
+		      struct cec_log_addrs *log_addrs, bool block);
+int cec_transmit_msg_fh(struct cec_adapter *adap, struct cec_msg *msg,
+			struct cec_fh *fh, bool block);
+void cec_queue_event_fh(struct cec_fh *fh,
+			const struct cec_event *new_ev, u64 ts);
+
+/* cec-api.c */
+extern const struct file_operations cec_devnode_fops;
+
+#endif

include/media/cec.h

+/*
+ * cec - HDMI Consumer Electronics Control support header
+ *
+ * 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.
+ */
+
+#ifndef _MEDIA_CEC_H
+#define _MEDIA_CEC_H
+
+#include <linux/poll.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/cdev.h>
+#include <linux/kthread.h>
+#include <linux/timer.h>
+#include <linux/cec-funcs.h>
+#include <media/rc-core.h>
+#include <media/cec-edid.h>
+
+/**
+ * struct cec_devnode - cec device node
+ * @dev:	cec device
+ * @cdev:	cec character device
+ * @parent:	parent device
+ * @minor:	device node minor number
+ * @registered:	the device was correctly registered
+ * @unregistered: the device was unregistered
+ * @fhs_lock:	lock to control access to the filehandle list
+ * @fhs:	the list of open filehandles (cec_fh)
+ *
+ * This structure represents a cec-related device node.
+ *
+ * The @parent is a physical device. It must be set by core or device drivers
+ * before registering the node.
+ */
+struct cec_devnode {
+	/* sysfs */
+	struct device dev;
+	struct cdev cdev;
+	struct device *parent;
+
+	/* device info */
+	int minor;
+	bool registered;
+	bool unregistered;
+	struct mutex fhs_lock;
+	struct list_head fhs;
+};
+
+struct cec_adapter;
+struct cec_data;
+
+struct cec_data {
+	struct list_head list;
+	struct list_head xfer_list;
+	struct cec_adapter *adap;
+	struct cec_msg msg;
+	struct cec_fh *fh;
+	struct delayed_work work;
+	struct completion c;
+	u8 attempts;
+	bool new_initiator;
+	bool blocking;
+	bool completed;
+};
+
+struct cec_msg_entry {
+	struct list_head	list;
+	struct cec_msg		msg;
+};
+
+#define CEC_NUM_EVENTS		CEC_EVENT_LOST_MSGS
+
+struct cec_fh {
+	struct list_head	list;
+	struct list_head	xfer_list;
+	struct cec_adapter	*adap;
+	u8			mode_initiator;
+	u8			mode_follower;
+
+	/* Events */
+	wait_queue_head_t	wait;
+	unsigned int		pending_events;
+	struct cec_event	events[CEC_NUM_EVENTS];
+	struct mutex		lock;
+	struct list_head	msgs; /* queued messages */
+	unsigned int		queued_msgs;
+};
+
+#define CEC_SIGNAL_FREE_TIME_RETRY		3
+#define CEC_SIGNAL_FREE_TIME_NEW_INITIATOR	5
+#define CEC_SIGNAL_FREE_TIME_NEXT_XFER		7
+
+/* The nominal data bit period is 2.4 ms */
+#define CEC_FREE_TIME_TO_USEC(ft)		((ft) * 2400)
+
+struct cec_adap_ops {
+	/* Low-level callbacks */
+	int (*adap_enable)(struct cec_adapter *adap, bool enable);
+	int (*adap_monitor_all_enable)(struct cec_adapter *adap, bool enable);
+	int (*adap_log_addr)(struct cec_adapter *adap, u8 logical_addr);
+	int (*adap_transmit)(struct cec_adapter *adap, u8 attempts,
+			     u32 signal_free_time, struct cec_msg *msg);
+	void (*adap_status)(struct cec_adapter *adap, struct seq_file *file);
+
+	/* High-level CEC message callback */
+	int (*received)(struct cec_adapter *adap, struct cec_msg *msg);
+};
+
+/*
+ * The minimum message length you can receive (excepting poll messages) is 2.
+ * With a transfer rate of at most 36 bytes per second this makes 18 messages
+ * per second worst case.
+ *
+ * We queue at most 3 seconds worth of messages. The CEC specification requires
+ * that messages are replied to within a second, so 3 seconds should give more
+ * than enough margin. Since most messages are actually more than 2 bytes, this
+ * is in practice a lot more than 3 seconds.
+ */
+#define CEC_MAX_MSG_QUEUE_SZ		(18 * 3)
+
+struct cec_adapter {
+	struct module *owner;
+	char name[32];
+	struct cec_devnode devnode;
+	struct mutex lock;
+	struct rc_dev *rc;
+
+	struct list_head transmit_queue;
+	struct list_head wait_queue;
+	struct cec_data *transmitting;
+
+	struct task_struct *kthread_config;
+	struct completion config_completion;
+
+	struct task_struct *kthread;
+	wait_queue_head_t kthread_waitq;
+	wait_queue_head_t waitq;
+
+	const struct cec_adap_ops *ops;
+	void *priv;
+	u32 capabilities;
+	u8 available_log_addrs;
+
+	u16 phys_addr;
+	bool is_configuring;
+	bool is_configured;
+	u32 monitor_all_cnt;
+	u32 follower_cnt;
+	struct cec_fh *cec_follower;
+	struct cec_fh *cec_initiator;
+	bool passthrough;
+	struct cec_log_addrs log_addrs;
+
+	struct dentry *cec_dir;
+	struct dentry *status_file;
+
+	u16 phys_addrs[15];
+	u32 sequence;
+
+	char input_name[32];
+	char input_phys[32];
+	char input_drv[32];
+};
+
+static inline bool cec_has_log_addr(const struct cec_adapter *adap, u8 log_addr)
+{
+	return adap->log_addrs.log_addr_mask & (1 << log_addr);
+}
+
+static inline bool cec_is_sink(const struct cec_adapter *adap)
+{
+	return adap->phys_addr == 0;
+}
+
+#if IS_ENABLED(CONFIG_MEDIA_CEC)
+struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
+		void *priv, const char *name, u32 caps, u8 available_las,
+		struct device *parent);
+int cec_register_adapter(struct cec_adapter *adap);
+void cec_unregister_adapter(struct cec_adapter *adap);
+void cec_delete_adapter(struct cec_adapter *adap);
+
+int cec_s_log_addrs(struct cec_adapter *adap, struct cec_log_addrs *log_addrs,
+		    bool block);
+void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
+		     bool block);
+int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
+		     bool block);
+
+/* Called by the adapter */
+void cec_transmit_done(struct cec_adapter *adap, u8 status, u8 arb_lost_cnt,
+		       u8 nack_cnt, u8 low_drive_cnt, u8 error_cnt);
+void cec_received_msg(struct cec_adapter *adap, struct cec_msg *msg);
+
+#else
+
+static inline int cec_register_adapter(struct cec_adapter *adap)
+{
+	return 0;
+}
+
+static inline void cec_unregister_adapter(struct cec_adapter *adap)
+{
+}
+
+static inline void cec_delete_adapter(struct cec_adapter *adap)
+{
+}
+
+static inline void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
+				   bool block)
+{
+}
+
+#endif
+
+#endif /* _MEDIA_CEC_H */