drivers/media/rc/rc-ir-raw.c

   1 /* rc-ir-raw.c - handle IR pulse/space events
   2  *
   3  * Copyright (C) 2010 by Mauro Carvalho Chehab
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation version 2 of the License.
   8  *
   9  *  This program is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *  GNU General Public License for more details.
  13  */
  14
  15 #include <linux/export.h>
  16 #include <linux/kthread.h>
  17 #include <linux/mutex.h>
  18 #include <linux/kmod.h>
  19 #include <linux/sched.h>
  20 #include <linux/freezer.h>
  21 #include "rc-core-priv.h"
  22
  23 /* Define the max number of pulse/space transitions to buffer */
  24 #define MAX_IR_EVENT_SIZE      512
  25
  26 /* Used to keep track of IR raw clients, protected by ir_raw_handler_lock */
  27 static LIST_HEAD(ir_raw_client_list);
  28
  29 /* Used to handle IR raw handler extensions */
  30 static DEFINE_MUTEX(ir_raw_handler_lock);
  31 static LIST_HEAD(ir_raw_handler_list);
  32 static u64 available_protocols;
  33
  34 static int ir_raw_event_thread(void *data)
  35 {
  36         struct ir_raw_event ev;
  37         struct ir_raw_handler *handler;
  38         struct ir_raw_event_ctrl *raw = (struct ir_raw_event_ctrl *)data;
  39         int retval;
  40
  41         while (!kthread_should_stop()) {
  42
  43                 spin_lock_irq(&raw->lock);
  44                 retval = kfifo_len(&raw->kfifo);
  45
  46                 if (retval < sizeof(ev)) {
  47                         set_current_state(TASK_INTERRUPTIBLE);
  48
  49                         if (kthread_should_stop())
  50                                 set_current_state(TASK_RUNNING);
  51
  52                         spin_unlock_irq(&raw->lock);
  53                         schedule();
  54                         continue;
  55                 }
  56
  57                 retval = kfifo_out(&raw->kfifo, &ev, sizeof(ev));
  58                 spin_unlock_irq(&raw->lock);
  59
  60                 mutex_lock(&ir_raw_handler_lock);
  61                 list_for_each_entry(handler, &ir_raw_handler_list, list)
  62                         if (raw->dev->enabled_protocols & handler->protocols ||
  63                             !handler->protocols)
  64                                 handler->decode(raw->dev, ev);
  65                 raw->prev_ev = ev;
  66                 mutex_unlock(&ir_raw_handler_lock);
  67         }
  68
  69         return 0;
  70 }
  71
  72 /**
  73  * ir_raw_event_store() - pass a pulse/space duration to the raw ir decoders
  74  * @dev:        the struct rc_dev device descriptor
  75  * @ev:         the struct ir_raw_event descriptor of the pulse/space
  76  *
  77  * This routine (which may be called from an interrupt context) stores a
  78  * pulse/space duration for the raw ir decoding state machines. Pulses are
  79  * signalled as positive values and spaces as negative values. A zero value
  80  * will reset the decoding state machines.
  81  */
  82 int ir_raw_event_store(struct rc_dev *dev, struct ir_raw_event *ev)
  83 {
  84         if (!dev->raw)
  85                 return -EINVAL;
  86
  87         IR_dprintk(2, "sample: (%05dus %s)\n",
  88                    TO_US(ev->duration), TO_STR(ev->pulse));
  89
  90         if (kfifo_in(&dev->raw->kfifo, ev, sizeof(*ev)) != sizeof(*ev))
  91                 return -ENOMEM;
  92
  93         return 0;
  94 }
  95 EXPORT_SYMBOL_GPL(ir_raw_event_store);
  96
  97 /**
  98  * ir_raw_event_store_edge() - notify raw ir decoders of the start of a pulse/space
  99  * @dev:        the struct rc_dev device descriptor
 100  * @type:       the type of the event that has occurred
 101  *
 102  * This routine (which may be called from an interrupt context) is used to
 103  * store the beginning of an ir pulse or space (or the start/end of ir
 104  * reception) for the raw ir decoding state machines. This is used by
 105  * hardware which does not provide durations directly but only interrupts
 106  * (or similar events) on state change.
 107  */
 108 int ir_raw_event_store_edge(struct rc_dev *dev, enum raw_event_type type)
 109 {
 110         ktime_t                 now;
 111         s64                     delta; /* ns */
 112         DEFINE_IR_RAW_EVENT(ev);
 113         int                     rc = 0;
 114         int                     delay;
 115
 116         if (!dev->raw)
 117                 return -EINVAL;
 118
 119         now = ktime_get();
 120         delta = ktime_to_ns(ktime_sub(now, dev->raw->last_event));
 121         delay = MS_TO_NS(dev->input_dev->rep[REP_DELAY]);
 122
 123         /* Check for a long duration since last event or if we're
 124          * being called for the first time, note that delta can't
 125          * possibly be negative.
 126          */
 127         if (delta > delay || !dev->raw->last_type)
 128                 type |= IR_START_EVENT;
 129         else
 130                 ev.duration = delta;
 131
 132         if (type & IR_START_EVENT)
 133                 ir_raw_event_reset(dev);
 134         else if (dev->raw->last_type & IR_SPACE) {
 135                 ev.pulse = false;
 136                 rc = ir_raw_event_store(dev, &ev);
 137         } else if (dev->raw->last_type & IR_PULSE) {
 138                 ev.pulse = true;
 139                 rc = ir_raw_event_store(dev, &ev);
 140         } else
 141                 return 0;
 142
 143         dev->raw->last_event = now;
 144         dev->raw->last_type = type;
 145         return rc;
 146 }
 147 EXPORT_SYMBOL_GPL(ir_raw_event_store_edge);
 148
 149 /**
 150  * ir_raw_event_store_with_filter() - pass next pulse/space to decoders with some processing
 151  * @dev:        the struct rc_dev device descriptor
 152  * @type:       the type of the event that has occurred
 153  *
 154  * This routine (which may be called from an interrupt context) works
 155  * in similar manner to ir_raw_event_store_edge.
 156  * This routine is intended for devices with limited internal buffer
 157  * It automerges samples of same type, and handles timeouts. Returns non-zero
 158  * if the event was added, and zero if the event was ignored due to idle
 159  * processing.
 160  */
 161 int ir_raw_event_store_with_filter(struct rc_dev *dev, struct ir_raw_event *ev)
 162 {
 163         if (!dev->raw)
 164                 return -EINVAL;
 165
 166         /* Ignore spaces in idle mode */
 167         if (dev->idle && !ev->pulse)
 168                 return 0;
 169         else if (dev->idle)
 170                 ir_raw_event_set_idle(dev, false);
 171
 172         if (!dev->raw->this_ev.duration)
 173                 dev->raw->this_ev = *ev;
 174         else if (ev->pulse == dev->raw->this_ev.pulse)
 175                 dev->raw->this_ev.duration += ev->duration;
 176         else {
 177                 ir_raw_event_store(dev, &dev->raw->this_ev);
 178                 dev->raw->this_ev = *ev;
 179         }
 180
 181         /* Enter idle mode if nessesary */
 182         if (!ev->pulse && dev->timeout &&
 183             dev->raw->this_ev.duration >= dev->timeout)
 184                 ir_raw_event_set_idle(dev, true);
 185
 186         return 1;
 187 }
 188 EXPORT_SYMBOL_GPL(ir_raw_event_store_with_filter);
 189
 190 /**
 191  * ir_raw_event_set_idle() - provide hint to rc-core when the device is idle or not
 192  * @dev:        the struct rc_dev device descriptor
 193  * @idle:       whether the device is idle or not
 194  */
 195 void ir_raw_event_set_idle(struct rc_dev *dev, bool idle)
 196 {
 197         if (!dev->raw)
 198                 return;
 199
 200         IR_dprintk(2, "%s idle mode\n", idle ? "enter" : "leave");
 201
 202         if (idle) {
 203                 dev->raw->this_ev.timeout = true;
 204                 ir_raw_event_store(dev, &dev->raw->this_ev);
 205                 init_ir_raw_event(&dev->raw->this_ev);
 206         }
 207
 208         if (dev->s_idle)
 209                 dev->s_idle(dev, idle);
 210
 211         dev->idle = idle;
 212 }
 213 EXPORT_SYMBOL_GPL(ir_raw_event_set_idle);
 214
 215 /**
 216  * ir_raw_event_handle() - schedules the decoding of stored ir data
 217  * @dev:        the struct rc_dev device descriptor
 218  *
 219  * This routine will tell rc-core to start decoding stored ir data.
 220  */
 221 void ir_raw_event_handle(struct rc_dev *dev)
 222 {
 223         unsigned long flags;
 224
 225         if (!dev->raw)
 226                 return;
 227
 228         spin_lock_irqsave(&dev->raw->lock, flags);
 229         wake_up_process(dev->raw->thread);
 230         spin_unlock_irqrestore(&dev->raw->lock, flags);
 231 }
 232 EXPORT_SYMBOL_GPL(ir_raw_event_handle);
 233
 234 /* used internally by the sysfs interface */
 235 u64
 236 ir_raw_get_allowed_protocols(void)
 237 {
 238         u64 protocols;
 239         mutex_lock(&ir_raw_handler_lock);
 240         protocols = available_protocols;
 241         mutex_unlock(&ir_raw_handler_lock);
 242         return protocols;
 243 }
 244
 245 static int change_protocol(struct rc_dev *dev, u64 *rc_type)
 246 {
 247         /* the caller will update dev->enabled_protocols */
 248         return 0;
 249 }
 250
 251 static void ir_raw_disable_protocols(struct rc_dev *dev, u64 protocols)
 252 {
 253         mutex_lock(&dev->lock);
 254         dev->enabled_protocols &= ~protocols;
 255         dev->enabled_wakeup_protocols &= ~protocols;
 256         mutex_unlock(&dev->lock);
 257 }
 258
 259 /*
 260  * Used to (un)register raw event clients
 261  */
 262 int ir_raw_event_register(struct rc_dev *dev)
 263 {
 264         int rc;
 265         struct ir_raw_handler *handler;
 266
 267         if (!dev)
 268                 return -EINVAL;
 269
 270         dev->raw = kzalloc(sizeof(*dev->raw), GFP_KERNEL);
 271         if (!dev->raw)
 272                 return -ENOMEM;
 273
 274         dev->raw->dev = dev;
 275         dev->change_protocol = change_protocol;
 276         rc = kfifo_alloc(&dev->raw->kfifo,
 277                          sizeof(struct ir_raw_event) * MAX_IR_EVENT_SIZE,
 278                          GFP_KERNEL);
 279         if (rc < 0)
 280                 goto out;
 281
 282         spin_lock_init(&dev->raw->lock);
 283         dev->raw->thread = kthread_run(ir_raw_event_thread, dev->raw,
 284                                        "rc%u", dev->minor);
 285
 286         if (IS_ERR(dev->raw->thread)) {
 287                 rc = PTR_ERR(dev->raw->thread);
 288                 goto out;
 289         }
 290
 291         mutex_lock(&ir_raw_handler_lock);
 292         list_add_tail(&dev->raw->list, &ir_raw_client_list);
 293         list_for_each_entry(handler, &ir_raw_handler_list, list)
 294                 if (handler->raw_register)
 295                         handler->raw_register(dev);
 296         mutex_unlock(&ir_raw_handler_lock);
 297
 298         return 0;
 299
 300 out:
 301         kfree(dev->raw);
 302         dev->raw = NULL;
 303         return rc;
 304 }
 305
 306 void ir_raw_event_unregister(struct rc_dev *dev)
 307 {
 308         struct ir_raw_handler *handler;
 309
 310         if (!dev || !dev->raw)
 311                 return;
 312
 313         kthread_stop(dev->raw->thread);
 314
 315         mutex_lock(&ir_raw_handler_lock);
 316         list_del(&dev->raw->list);
 317         list_for_each_entry(handler, &ir_raw_handler_list, list)
 318                 if (handler->raw_unregister)
 319                         handler->raw_unregister(dev);
 320         mutex_unlock(&ir_raw_handler_lock);
 321
 322         kfifo_free(&dev->raw->kfifo);
 323         kfree(dev->raw);
 324         dev->raw = NULL;
 325 }
 326
 327 /*
 328  * Extension interface - used to register the IR decoders
 329  */
 330
 331 int ir_raw_handler_register(struct ir_raw_handler *ir_raw_handler)
 332 {
 333         struct ir_raw_event_ctrl *raw;
 334
 335         mutex_lock(&ir_raw_handler_lock);
 336         list_add_tail(&ir_raw_handler->list, &ir_raw_handler_list);
 337         if (ir_raw_handler->raw_register)
 338                 list_for_each_entry(raw, &ir_raw_client_list, list)
 339                         ir_raw_handler->raw_register(raw->dev);
 340         available_protocols |= ir_raw_handler->protocols;
 341         mutex_unlock(&ir_raw_handler_lock);
 342
 343         return 0;
 344 }
 345 EXPORT_SYMBOL(ir_raw_handler_register);
 346
 347 void ir_raw_handler_unregister(struct ir_raw_handler *ir_raw_handler)
 348 {
 349         struct ir_raw_event_ctrl *raw;
 350         u64 protocols = ir_raw_handler->protocols;
 351
 352         mutex_lock(&ir_raw_handler_lock);
 353         list_del(&ir_raw_handler->list);
 354         list_for_each_entry(raw, &ir_raw_client_list, list) {
 355                 ir_raw_disable_protocols(raw->dev, protocols);
 356                 if (ir_raw_handler->raw_unregister)
 357                         ir_raw_handler->raw_unregister(raw->dev);
 358         }
 359         available_protocols &= ~protocols;
 360         mutex_unlock(&ir_raw_handler_lock);
 361 }
 362 EXPORT_SYMBOL(ir_raw_handler_unregister);