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

#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>

#define CEC_CAP_DEFAULTS (CEC_CAP_LOG_ADDRS | CEC_CAP_TRANSMIT | \
                          CEC_CAP_PASSTHROUGH | CEC_CAP_RC)

/**
 * struct cec_devnode - cec device node
 * @dev:        cec device
 * @cdev:       cec character device
 * @minor:      device node minor number
 * @registered: the device was correctly registered
 * @unregistered: the device was unregistered
 * @fhs:        the list of open filehandles (cec_fh)
 * @lock:       lock to control access to this structure
 *
 * 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;

        /* device info */
        int minor;
        bool registered;
        bool unregistered;
        struct list_head fhs;
        struct mutex lock;
};

struct cec_adapter;
struct cec_data;
struct cec_pin;
struct cec_notifier;

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 blocking;
        bool completed;
};

struct cec_msg_entry {
        struct list_head        list;
        struct cec_msg          msg;
};

struct cec_event_entry {
        struct list_head        list;
        struct cec_event        ev;
};

#define CEC_NUM_CORE_EVENTS 2
#define CEC_NUM_EVENTS CEC_EVENT_PIN_5V_HIGH

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;
        struct mutex            lock;
        struct list_head        events[CEC_NUM_EVENTS]; /* queued events */
        u16                     queued_events[CEC_NUM_EVENTS];
        unsigned int            total_queued_events;
        struct cec_event_entry  core_events[CEC_NUM_CORE_EVENTS];
        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_monitor_pin_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);
        void (*adap_free)(struct cec_adapter *adap);

        /* Error injection callbacks */
        int (*error_inj_show)(struct cec_adapter *adap, struct seq_file *sf);
        bool (*error_inj_parse_line)(struct cec_adapter *adap, char *line);

        /* 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 received 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_RX_QUEUE_SZ         (18 * 3)

/*
 * The transmit queue is limited to 1 second worth of messages (worst case).
 * Messages can be transmitted by userspace and kernel space. But for both it
 * makes no sense to have a lot of messages queued up. One second seems
 * reasonable.
 */
#define CEC_MAX_MSG_TX_QUEUE_SZ         (18 * 1)

/**
 * struct cec_adapter - cec adapter structure
 * @owner:              module owner
 * @name:               name of the CEC adapter
 * @devnode:            device node for the /dev/cecX device
 * @lock:               mutex controlling access to this structure
 * @rc:                 remote control device
 * @transmit_queue:     queue of pending transmits
 * @transmit_queue_sz:  number of pending transmits
 * @wait_queue:         queue of transmits waiting for a reply
 * @transmitting:       CEC messages currently being transmitted
 * @transmit_in_progress: true if a transmit is in progress
 * @kthread_config:     kthread used to configure a CEC adapter
 * @config_completion:  used to signal completion of the config kthread
 * @kthread:            main CEC processing thread
 * @kthread_waitq:      main CEC processing wait_queue
 * @ops:                cec adapter ops
 * @priv:               cec driver's private data
 * @capabilities:       cec adapter capabilities
 * @available_log_addrs: maximum number of available logical addresses
 * @phys_addr:          the current physical address
 * @needs_hpd:          if true, then the HDMI HotPlug Detect pin must be high
 *      in order to transmit or receive CEC messages. This is usually a HW
 *      limitation.
 * @is_configuring:     the CEC adapter is configuring (i.e. claiming LAs)
 * @is_configured:      the CEC adapter is configured (i.e. has claimed LAs)
 * @cec_pin_is_high:    if true then the CEC pin is high. Only used with the
 *      CEC pin framework.
 * @adap_controls_phys_addr: if true, then the CEC adapter controls the
 *      physical address, i.e. the CEC hardware can detect HPD changes and
 *      read the EDID and is not dependent on an external HDMI driver.
 *      Drivers that need this can set this field to true after the
 *      cec_allocate_adapter() call.
 * @last_initiator:     the initiator of the last transmitted message.
 * @monitor_all_cnt:    number of filehandles monitoring all msgs
 * @monitor_pin_cnt:    number of filehandles monitoring pin changes
 * @follower_cnt:       number of filehandles in follower mode
 * @cec_follower:       filehandle of the exclusive follower
 * @cec_initiator:      filehandle of the exclusive initiator
 * @passthrough:        if true, then the exclusive follower is in
 *      passthrough mode.
 * @log_addrs:          current logical addresses
 * @conn_info:          current connector info
 * @tx_timeouts:        number of transmit timeouts
 * @notifier:           CEC notifier
 * @pin:                CEC pin status struct
 * @cec_dir:            debugfs cec directory
 * @status_file:        debugfs cec status file
 * @error_inj_file:     debugfs cec error injection file
 * @sequence:           transmit sequence counter
 * @input_phys:         remote control input_phys name
 *
 * This structure represents a cec adapter.
 */
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;
        unsigned int transmit_queue_sz;
        struct list_head wait_queue;
        struct cec_data *transmitting;
        bool transmit_in_progress;

        struct task_struct *kthread_config;
        struct completion config_completion;

        struct task_struct *kthread;
        wait_queue_head_t kthread_waitq;

        const struct cec_adap_ops *ops;
        void *priv;
        u32 capabilities;
        u8 available_log_addrs;

        u16 phys_addr;
        bool needs_hpd;
        bool is_configuring;
        bool is_configured;
        bool cec_pin_is_high;
        bool adap_controls_phys_addr;
        u8 last_initiator;
        u32 monitor_all_cnt;
        u32 monitor_pin_cnt;
        u32 follower_cnt;
        struct cec_fh *cec_follower;
        struct cec_fh *cec_initiator;
        bool passthrough;
        struct cec_log_addrs log_addrs;
        struct cec_connector_info conn_info;

        u32 tx_timeouts;

#ifdef CONFIG_CEC_NOTIFIER
        struct cec_notifier *notifier;
#endif
#ifdef CONFIG_CEC_PIN
        struct cec_pin *pin;
#endif

        struct dentry *cec_dir;

        u32 sequence;

        char input_phys[32];
};

static inline void *cec_get_drvdata(const struct cec_adapter *adap)
{
        return adap->priv;
}

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;
}

/**
 * cec_is_registered() - is the CEC adapter registered?
 *
 * @adap:       the CEC adapter, may be NULL.
 *
 * Return: true if the adapter is registered, false otherwise.
 */
static inline bool cec_is_registered(const struct cec_adapter *adap)
{
        return adap && adap->devnode.registered;
}

#define cec_phys_addr_exp(pa) \
        ((pa) >> 12), ((pa) >> 8) & 0xf, ((pa) >> 4) & 0xf, (pa) & 0xf

struct edid;
struct drm_connector;

#if IS_REACHABLE(CONFIG_CEC_CORE)
struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
                void *priv, const char *name, u32 caps, u8 available_las);
int cec_register_adapter(struct cec_adapter *adap, struct device *parent);
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);
void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
                               const struct edid *edid);
void cec_s_conn_info(struct cec_adapter *adap,
                     const struct cec_connector_info *conn_info);
int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
                     bool block);

/* Called by the adapter */
void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
                          u8 arb_lost_cnt, u8 nack_cnt, u8 low_drive_cnt,
                          u8 error_cnt, ktime_t ts);

static inline void cec_transmit_done(struct cec_adapter *adap, u8 status,
                                     u8 arb_lost_cnt, u8 nack_cnt,
                                     u8 low_drive_cnt, u8 error_cnt)
{
        cec_transmit_done_ts(adap, status, arb_lost_cnt, nack_cnt,
                             low_drive_cnt, error_cnt, ktime_get());
}
/*
 * Simplified version of cec_transmit_done for hardware that doesn't retry
 * failed transmits. So this is always just one attempt in which case
 * the status is sufficient.
 */
void cec_transmit_attempt_done_ts(struct cec_adapter *adap,
                                  u8 status, ktime_t ts);

static inline void cec_transmit_attempt_done(struct cec_adapter *adap,
                                             u8 status)
{
        cec_transmit_attempt_done_ts(adap, status, ktime_get());
}

void cec_received_msg_ts(struct cec_adapter *adap,
                         struct cec_msg *msg, ktime_t ts);

static inline void cec_received_msg(struct cec_adapter *adap,
                                    struct cec_msg *msg)
{
        cec_received_msg_ts(adap, msg, ktime_get());
}

/**
 * cec_queue_pin_cec_event() - queue a CEC pin event with a given timestamp.
 *
 * @adap:       pointer to the cec adapter
 * @is_high:    when true the CEC pin is high, otherwise it is low
 * @dropped_events: when true some events were dropped
 * @ts:         the timestamp for this event
 *
 */
void cec_queue_pin_cec_event(struct cec_adapter *adap, bool is_high,
                             bool dropped_events, ktime_t ts);

/**
 * cec_queue_pin_hpd_event() - queue a pin event with a given timestamp.
 *
 * @adap:       pointer to the cec adapter
 * @is_high:    when true the HPD pin is high, otherwise it is low
 * @ts:         the timestamp for this event
 *
 */
void cec_queue_pin_hpd_event(struct cec_adapter *adap, bool is_high, ktime_t ts);

/**
 * cec_queue_pin_5v_event() - queue a pin event with a given timestamp.
 *
 * @adap:       pointer to the cec adapter
 * @is_high:    when true the 5V pin is high, otherwise it is low
 * @ts:         the timestamp for this event
 *
 */
void cec_queue_pin_5v_event(struct cec_adapter *adap, bool is_high, ktime_t ts);

/**
 * cec_get_edid_phys_addr() - find and return the physical address
 *
 * @edid:       pointer to the EDID data
 * @size:       size in bytes of the EDID data
 * @offset:     If not %NULL then the location of the physical address
 *              bytes in the EDID will be returned here. This is set to 0
 *              if there is no physical address found.
 *
 * Return: the physical address or CEC_PHYS_ADDR_INVALID if there is none.
 */
u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
                           unsigned int *offset);

void cec_fill_conn_info_from_drm(struct cec_connector_info *conn_info,
                                 const struct drm_connector *connector);

#else

static inline int cec_register_adapter(struct cec_adapter *adap,
                                       struct device *parent)
{
        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)
{
}

static inline void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
                                             const struct edid *edid)
{
}

static inline u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
                                         unsigned int *offset)
{
        if (offset)
                *offset = 0;
        return CEC_PHYS_ADDR_INVALID;
}

static inline void cec_s_conn_info(struct cec_adapter *adap,
                                   const struct cec_connector_info *conn_info)
{
}

static inline void
cec_fill_conn_info_from_drm(struct cec_connector_info *conn_info,
                            const struct drm_connector *connector)
{
        memset(conn_info, 0, sizeof(*conn_info));
}

#endif

/**
 * cec_phys_addr_invalidate() - set the physical address to INVALID
 *
 * @adap:       the CEC adapter
 *
 * This is a simple helper function to invalidate the physical
 * address.
 */
static inline void cec_phys_addr_invalidate(struct cec_adapter *adap)
{
        cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
}

/**
 * cec_get_edid_spa_location() - find location of the Source Physical Address
 *
 * @edid: the EDID
 * @size: the size of the EDID
 *
 * This EDID is expected to be a CEA-861 compliant, which means that there are
 * at least two blocks and one or more of the extensions blocks are CEA-861
 * blocks.
 *
 * The returned location is guaranteed to be <= size-2.
 *
 * This is an inline function since it is used by both CEC and V4L2.
 * Ideally this would go in a module shared by both, but it is overkill to do
 * that for just a single function.
 */
static inline unsigned int cec_get_edid_spa_location(const u8 *edid,
                                                     unsigned int size)
{
        unsigned int blocks = size / 128;
        unsigned int block;
        u8 d;

        /* Sanity check: at least 2 blocks and a multiple of the block size */
        if (blocks < 2 || size % 128)
                return 0;

        /*
         * If there are fewer extension blocks than the size, then update
         * 'blocks'. It is allowed to have more extension blocks than the size,
         * since some hardware can only read e.g. 256 bytes of the EDID, even
         * though more blocks are present. The first CEA-861 extension block
         * should normally be in block 1 anyway.
         */
        if (edid[0x7e] + 1 < blocks)
                blocks = edid[0x7e] + 1;

        for (block = 1; block < blocks; block++) {
                unsigned int offset = block * 128;

                /* Skip any non-CEA-861 extension blocks */
                if (edid[offset] != 0x02 || edid[offset + 1] != 0x03)
                        continue;

                /* search Vendor Specific Data Block (tag 3) */
                d = edid[offset + 2] & 0x7f;
                /* Check if there are Data Blocks */
                if (d <= 4)
                        continue;
                if (d > 4) {
                        unsigned int i = offset + 4;
                        unsigned int end = offset + d;

                        /* Note: 'end' is always < 'size' */
                        do {
                                u8 tag = edid[i] >> 5;
                                u8 len = edid[i] & 0x1f;

                                if (tag == 3 && len >= 5 && i + len <= end &&
                                    edid[i + 1] == 0x03 &&
                                    edid[i + 2] == 0x0c &&
                                    edid[i + 3] == 0x00)
                                        return i + 4;
                                i += len + 1;
                        } while (i < end);
                }
        }
        return 0;
}

#endif /* _MEDIA_CEC_H */