include/media/cec.h

   1 /*
   2  * cec - HDMI Consumer Electronics Control support header
   3  *
   4  * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
   5  *
   6  * This program is free software; you may redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; version 2 of the License.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  11  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  12  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  13  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  14  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  15  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  16  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  17  * SOFTWARE.
  18  */
  19
  20 #ifndef _MEDIA_CEC_H
  21 #define _MEDIA_CEC_H
  22
  23 #include <linux/poll.h>
  24 #include <linux/fs.h>
  25 #include <linux/debugfs.h>
  26 #include <linux/device.h>
  27 #include <linux/cdev.h>
  28 #include <linux/kthread.h>
  29 #include <linux/timer.h>
  30 #include <linux/cec-funcs.h>
  31 #include <media/rc-core.h>
  32 #include <media/cec-edid.h>
  33
  34 /**
  35  * struct cec_devnode - cec device node
  36  * @dev:        cec device
  37  * @cdev:       cec character device
  38  * @minor:      device node minor number
  39  * @registered: the device was correctly registered
  40  * @unregistered: the device was unregistered
  41  * @fhs_lock:   lock to control access to the filehandle list
  42  * @fhs:        the list of open filehandles (cec_fh)
  43  *
  44  * This structure represents a cec-related device node.
  45  *
  46  * The @parent is a physical device. It must be set by core or device drivers
  47  * before registering the node.
  48  */
  49 struct cec_devnode {
  50         /* sysfs */
  51         struct device dev;
  52         struct cdev cdev;
  53
  54         /* device info */
  55         int minor;
  56         bool registered;
  57         bool unregistered;
  58         struct list_head fhs;
  59         struct mutex lock;
  60 };
  61
  62 struct cec_adapter;
  63 struct cec_data;
  64
  65 struct cec_data {
  66         struct list_head list;
  67         struct list_head xfer_list;
  68         struct cec_adapter *adap;
  69         struct cec_msg msg;
  70         struct cec_fh *fh;
  71         struct delayed_work work;
  72         struct completion c;
  73         u8 attempts;
  74         bool new_initiator;
  75         bool blocking;
  76         bool completed;
  77 };
  78
  79 struct cec_msg_entry {
  80         struct list_head        list;
  81         struct cec_msg          msg;
  82 };
  83
  84 #define CEC_NUM_EVENTS          CEC_EVENT_LOST_MSGS
  85
  86 struct cec_fh {
  87         struct list_head        list;
  88         struct list_head        xfer_list;
  89         struct cec_adapter      *adap;
  90         u8                      mode_initiator;
  91         u8                      mode_follower;
  92
  93         /* Events */
  94         wait_queue_head_t       wait;
  95         unsigned int            pending_events;
  96         struct cec_event        events[CEC_NUM_EVENTS];
  97         struct mutex            lock;
  98         struct list_head        msgs; /* queued messages */
  99         unsigned int            queued_msgs;
 100 };
 101
 102 #define CEC_SIGNAL_FREE_TIME_RETRY              3
 103 #define CEC_SIGNAL_FREE_TIME_NEW_INITIATOR      5
 104 #define CEC_SIGNAL_FREE_TIME_NEXT_XFER          7
 105
 106 /* The nominal data bit period is 2.4 ms */
 107 #define CEC_FREE_TIME_TO_USEC(ft)               ((ft) * 2400)
 108
 109 struct cec_adap_ops {
 110         /* Low-level callbacks */
 111         int (*adap_enable)(struct cec_adapter *adap, bool enable);
 112         int (*adap_monitor_all_enable)(struct cec_adapter *adap, bool enable);
 113         int (*adap_log_addr)(struct cec_adapter *adap, u8 logical_addr);
 114         int (*adap_transmit)(struct cec_adapter *adap, u8 attempts,
 115                              u32 signal_free_time, struct cec_msg *msg);
 116         void (*adap_status)(struct cec_adapter *adap, struct seq_file *file);
 117
 118         /* High-level CEC message callback */
 119         int (*received)(struct cec_adapter *adap, struct cec_msg *msg);
 120 };
 121
 122 /*
 123  * The minimum message length you can receive (excepting poll messages) is 2.
 124  * With a transfer rate of at most 36 bytes per second this makes 18 messages
 125  * per second worst case.
 126  *
 127  * We queue at most 3 seconds worth of received messages. The CEC specification
 128  * requires that messages are replied to within a second, so 3 seconds should
 129  * give more than enough margin. Since most messages are actually more than 2
 130  * bytes, this is in practice a lot more than 3 seconds.
 131  */
 132 #define CEC_MAX_MSG_RX_QUEUE_SZ         (18 * 3)
 133
 134 /*
 135  * The transmit queue is limited to 1 second worth of messages (worst case).
 136  * Messages can be transmitted by userspace and kernel space. But for both it
 137  * makes no sense to have a lot of messages queued up. One second seems
 138  * reasonable.
 139  */
 140 #define CEC_MAX_MSG_TX_QUEUE_SZ         (18 * 1)
 141
 142 struct cec_adapter {
 143         struct module *owner;
 144         char name[32];
 145         struct cec_devnode devnode;
 146         struct mutex lock;
 147         struct rc_dev *rc;
 148
 149         struct list_head transmit_queue;
 150         unsigned int transmit_queue_sz;
 151         struct list_head wait_queue;
 152         struct cec_data *transmitting;
 153
 154         struct task_struct *kthread_config;
 155         struct completion config_completion;
 156
 157         struct task_struct *kthread;
 158         wait_queue_head_t kthread_waitq;
 159         wait_queue_head_t waitq;
 160
 161         const struct cec_adap_ops *ops;
 162         void *priv;
 163         u32 capabilities;
 164         u8 available_log_addrs;
 165
 166         u16 phys_addr;
 167         bool is_configuring;
 168         bool is_configured;
 169         u32 monitor_all_cnt;
 170         u32 follower_cnt;
 171         struct cec_fh *cec_follower;
 172         struct cec_fh *cec_initiator;
 173         bool passthrough;
 174         struct cec_log_addrs log_addrs;
 175
 176         struct dentry *cec_dir;
 177         struct dentry *status_file;
 178
 179         u16 phys_addrs[15];
 180         u32 sequence;
 181
 182         char input_name[32];
 183         char input_phys[32];
 184         char input_drv[32];
 185 };
 186
 187 static inline bool cec_has_log_addr(const struct cec_adapter *adap, u8 log_addr)
 188 {
 189         return adap->log_addrs.log_addr_mask & (1 << log_addr);
 190 }
 191
 192 static inline bool cec_is_sink(const struct cec_adapter *adap)
 193 {
 194         return adap->phys_addr == 0;
 195 }
 196
 197 #if IS_ENABLED(CONFIG_MEDIA_CEC_SUPPORT)
 198 struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
 199                 void *priv, const char *name, u32 caps, u8 available_las);
 200 int cec_register_adapter(struct cec_adapter *adap, struct device *parent);
 201 void cec_unregister_adapter(struct cec_adapter *adap);
 202 void cec_delete_adapter(struct cec_adapter *adap);
 203
 204 int cec_s_log_addrs(struct cec_adapter *adap, struct cec_log_addrs *log_addrs,
 205                     bool block);
 206 void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
 207                      bool block);
 208 int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
 209                      bool block);
 210
 211 /* Called by the adapter */
 212 void cec_transmit_done(struct cec_adapter *adap, u8 status, u8 arb_lost_cnt,
 213                        u8 nack_cnt, u8 low_drive_cnt, u8 error_cnt);
 214 void cec_received_msg(struct cec_adapter *adap, struct cec_msg *msg);
 215
 216 #else
 217
 218 static inline int cec_register_adapter(struct cec_adapter *adap,
 219                                        struct device *parent)
 220 {
 221         return 0;
 222 }
 223
 224 static inline void cec_unregister_adapter(struct cec_adapter *adap)
 225 {
 226 }
 227
 228 static inline void cec_delete_adapter(struct cec_adapter *adap)
 229 {
 230 }
 231
 232 static inline void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
 233                                    bool block)
 234 {
 235 }
 236
 237 #endif
 238
 239 #endif /* _MEDIA_CEC_H */