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  * @parent:     parent device
  39  * @minor:      device node minor number
  40  * @registered: the device was correctly registered
  41  * @unregistered: the device was unregistered
  42  * @fhs_lock:   lock to control access to the filehandle list
  43  * @fhs:        the list of open filehandles (cec_fh)
  44  *
  45  * This structure represents a cec-related device node.
  46  *
  47  * The @parent is a physical device. It must be set by core or device drivers
  48  * before registering the node.
  49  */
  50 struct cec_devnode {
  51         /* sysfs */
  52         struct device dev;
  53         struct cdev cdev;
  54         struct device *parent;
  55
  56         /* device info */
  57         int minor;
  58         bool registered;
  59         bool unregistered;
  60         struct mutex fhs_lock;
  61         struct list_head fhs;
  62 };
  63
  64 struct cec_adapter;
  65 struct cec_data;
  66
  67 struct cec_data {
  68         struct list_head list;
  69         struct list_head xfer_list;
  70         struct cec_adapter *adap;
  71         struct cec_msg msg;
  72         struct cec_fh *fh;
  73         struct delayed_work work;
  74         struct completion c;
  75         u8 attempts;
  76         bool new_initiator;
  77         bool blocking;
  78         bool completed;
  79 };
  80
  81 struct cec_msg_entry {
  82         struct list_head        list;
  83         struct cec_msg          msg;
  84 };
  85
  86 #define CEC_NUM_EVENTS          CEC_EVENT_LOST_MSGS
  87
  88 struct cec_fh {
  89         struct list_head        list;
  90         struct list_head        xfer_list;
  91         struct cec_adapter      *adap;
  92         u8                      mode_initiator;
  93         u8                      mode_follower;
  94
  95         /* Events */
  96         wait_queue_head_t       wait;
  97         unsigned int            pending_events;
  98         struct cec_event        events[CEC_NUM_EVENTS];
  99         struct mutex            lock;
 100         struct list_head        msgs; /* queued messages */
 101         unsigned int            queued_msgs;
 102 };
 103
 104 #define CEC_SIGNAL_FREE_TIME_RETRY              3
 105 #define CEC_SIGNAL_FREE_TIME_NEW_INITIATOR      5
 106 #define CEC_SIGNAL_FREE_TIME_NEXT_XFER          7
 107
 108 /* The nominal data bit period is 2.4 ms */
 109 #define CEC_FREE_TIME_TO_USEC(ft)               ((ft) * 2400)
 110
 111 struct cec_adap_ops {
 112         /* Low-level callbacks */
 113         int (*adap_enable)(struct cec_adapter *adap, bool enable);
 114         int (*adap_monitor_all_enable)(struct cec_adapter *adap, bool enable);
 115         int (*adap_log_addr)(struct cec_adapter *adap, u8 logical_addr);
 116         int (*adap_transmit)(struct cec_adapter *adap, u8 attempts,
 117                              u32 signal_free_time, struct cec_msg *msg);
 118         void (*adap_status)(struct cec_adapter *adap, struct seq_file *file);
 119
 120         /* High-level CEC message callback */
 121         int (*received)(struct cec_adapter *adap, struct cec_msg *msg);
 122 };
 123
 124 /*
 125  * The minimum message length you can receive (excepting poll messages) is 2.
 126  * With a transfer rate of at most 36 bytes per second this makes 18 messages
 127  * per second worst case.
 128  *
 129  * We queue at most 3 seconds worth of received messages. The CEC specification
 130  * requires that messages are replied to within a second, so 3 seconds should
 131  * give more than enough margin. Since most messages are actually more than 2
 132  * bytes, this is in practice a lot more than 3 seconds.
 133  */
 134 #define CEC_MAX_MSG_RX_QUEUE_SZ         (18 * 3)
 135
 136 /*
 137  * The transmit queue is limited to 1 second worth of messages (worst case).
 138  * Messages can be transmitted by userspace and kernel space. But for both it
 139  * makes no sense to have a lot of messages queued up. One second seems
 140  * reasonable.
 141  */
 142 #define CEC_MAX_MSG_TX_QUEUE_SZ         (18 * 1)
 143
 144 struct cec_adapter {
 145         struct module *owner;
 146         char name[32];
 147         struct cec_devnode devnode;
 148         struct mutex lock;
 149         struct rc_dev *rc;
 150
 151         struct list_head transmit_queue;
 152         unsigned int transmit_queue_sz;
 153         struct list_head wait_queue;
 154         struct cec_data *transmitting;
 155
 156         struct task_struct *kthread_config;
 157         struct completion config_completion;
 158
 159         struct task_struct *kthread;
 160         wait_queue_head_t kthread_waitq;
 161         wait_queue_head_t waitq;
 162
 163         const struct cec_adap_ops *ops;
 164         void *priv;
 165         u32 capabilities;
 166         u8 available_log_addrs;
 167
 168         u16 phys_addr;
 169         bool is_configuring;
 170         bool is_configured;
 171         u32 monitor_all_cnt;
 172         u32 follower_cnt;
 173         struct cec_fh *cec_follower;
 174         struct cec_fh *cec_initiator;
 175         bool passthrough;
 176         struct cec_log_addrs log_addrs;
 177
 178         struct dentry *cec_dir;
 179         struct dentry *status_file;
 180
 181         u16 phys_addrs[15];
 182         u32 sequence;
 183
 184         char input_name[32];
 185         char input_phys[32];
 186         char input_drv[32];
 187 };
 188
 189 static inline bool cec_has_log_addr(const struct cec_adapter *adap, u8 log_addr)
 190 {
 191         return adap->log_addrs.log_addr_mask & (1 << log_addr);
 192 }
 193
 194 static inline bool cec_is_sink(const struct cec_adapter *adap)
 195 {
 196         return adap->phys_addr == 0;
 197 }
 198
 199 #if IS_ENABLED(CONFIG_MEDIA_CEC)
 200 struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
 201                 void *priv, const char *name, u32 caps, u8 available_las,
 202                 struct device *parent);
 203 int cec_register_adapter(struct cec_adapter *adap);
 204 void cec_unregister_adapter(struct cec_adapter *adap);
 205 void cec_delete_adapter(struct cec_adapter *adap);
 206
 207 int cec_s_log_addrs(struct cec_adapter *adap, struct cec_log_addrs *log_addrs,
 208                     bool block);
 209 void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
 210                      bool block);
 211 int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
 212                      bool block);
 213
 214 /* Called by the adapter */
 215 void cec_transmit_done(struct cec_adapter *adap, u8 status, u8 arb_lost_cnt,
 216                        u8 nack_cnt, u8 low_drive_cnt, u8 error_cnt);
 217 void cec_received_msg(struct cec_adapter *adap, struct cec_msg *msg);
 218
 219 #else
 220
 221 static inline int cec_register_adapter(struct cec_adapter *adap)
 222 {
 223         return 0;
 224 }
 225
 226 static inline void cec_unregister_adapter(struct cec_adapter *adap)
 227 {
 228 }
 229
 230 static inline void cec_delete_adapter(struct cec_adapter *adap)
 231 {
 232 }
 233
 234 static inline void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
 235                                    bool block)
 236 {
 237 }
 238
 239 #endif
 240
 241 #endif /* _MEDIA_CEC_H */