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 /* Used to keep track of IR raw clients, protected by ir_raw_handler_lock */
  24 static LIST_HEAD(ir_raw_client_list);
  25
  26 /* Used to handle IR raw handler extensions */
  27 static DEFINE_MUTEX(ir_raw_handler_lock);
  28 static LIST_HEAD(ir_raw_handler_list);
  29 static atomic64_t available_protocols = ATOMIC64_INIT(0);
  30
  31 static int ir_raw_event_thread(void *data)
  32 {
  33         struct ir_raw_event ev;
  34         struct ir_raw_handler *handler;
  35         struct ir_raw_event_ctrl *raw = (struct ir_raw_event_ctrl *)data;
  36
  37         while (!kthread_should_stop()) {
  38
  39                 spin_lock_irq(&raw->lock);
  40
  41                 if (!kfifo_len(&raw->kfifo)) {
  42                         set_current_state(TASK_INTERRUPTIBLE);
  43
  44                         if (kthread_should_stop())
  45                                 set_current_state(TASK_RUNNING);
  46
  47                         spin_unlock_irq(&raw->lock);
  48                         schedule();
  49                         continue;
  50                 }
  51
  52                 if(!kfifo_out(&raw->kfifo, &ev, 1))
  53                         dev_err(&raw->dev->dev, "IR event FIFO is empty!\n");
  54                 spin_unlock_irq(&raw->lock);
  55
  56                 mutex_lock(&ir_raw_handler_lock);
  57                 list_for_each_entry(handler, &ir_raw_handler_list, list)
  58                         if (raw->dev->enabled_protocols & handler->protocols ||
  59                             !handler->protocols)
  60                                 handler->decode(raw->dev, ev);
  61                 raw->prev_ev = ev;
  62                 mutex_unlock(&ir_raw_handler_lock);
  63         }
  64
  65         return 0;
  66 }
  67
  68 /**
  69  * ir_raw_event_store() - pass a pulse/space duration to the raw ir decoders
  70  * @dev:        the struct rc_dev device descriptor
  71  * @ev:         the struct ir_raw_event descriptor of the pulse/space
  72  *
  73  * This routine (which may be called from an interrupt context) stores a
  74  * pulse/space duration for the raw ir decoding state machines. Pulses are
  75  * signalled as positive values and spaces as negative values. A zero value
  76  * will reset the decoding state machines.
  77  */
  78 int ir_raw_event_store(struct rc_dev *dev, struct ir_raw_event *ev)
  79 {
  80         if (!dev->raw)
  81                 return -EINVAL;
  82
  83         IR_dprintk(2, "sample: (%05dus %s)\n",
  84                    TO_US(ev->duration), TO_STR(ev->pulse));
  85
  86         if (!kfifo_put(&dev->raw->kfifo, *ev)) {
  87                 dev_err(&dev->dev, "IR event FIFO is full!\n");
  88                 return -ENOSPC;
  89         }
  90
  91         return 0;
  92 }
  93 EXPORT_SYMBOL_GPL(ir_raw_event_store);
  94
  95 /**
  96  * ir_raw_event_store_edge() - notify raw ir decoders of the start of a pulse/space
  97  * @dev:        the struct rc_dev device descriptor
  98  * @type:       the type of the event that has occurred
  99  *
 100  * This routine (which may be called from an interrupt context) is used to
 101  * store the beginning of an ir pulse or space (or the start/end of ir
 102  * reception) for the raw ir decoding state machines. This is used by
 103  * hardware which does not provide durations directly but only interrupts
 104  * (or similar events) on state change.
 105  */
 106 int ir_raw_event_store_edge(struct rc_dev *dev, enum raw_event_type type)
 107 {
 108         ktime_t                 now;
 109         s64                     delta; /* ns */
 110         DEFINE_IR_RAW_EVENT(ev);
 111         int                     rc = 0;
 112         int                     delay;
 113
 114         if (!dev->raw)
 115                 return -EINVAL;
 116
 117         now = ktime_get();
 118         delta = ktime_to_ns(ktime_sub(now, dev->raw->last_event));
 119         delay = MS_TO_NS(dev->input_dev->rep[REP_DELAY]);
 120
 121         /* Check for a long duration since last event or if we're
 122          * being called for the first time, note that delta can't
 123          * possibly be negative.
 124          */
 125         if (delta > delay || !dev->raw->last_type)
 126                 type |= IR_START_EVENT;
 127         else
 128                 ev.duration = delta;
 129
 130         if (type & IR_START_EVENT)
 131                 ir_raw_event_reset(dev);
 132         else if (dev->raw->last_type & IR_SPACE) {
 133                 ev.pulse = false;
 134                 rc = ir_raw_event_store(dev, &ev);
 135         } else if (dev->raw->last_type & IR_PULSE) {
 136                 ev.pulse = true;
 137                 rc = ir_raw_event_store(dev, &ev);
 138         } else
 139                 return 0;
 140
 141         dev->raw->last_event = now;
 142         dev->raw->last_type = type;
 143         return rc;
 144 }
 145 EXPORT_SYMBOL_GPL(ir_raw_event_store_edge);
 146
 147 /**
 148  * ir_raw_event_store_with_filter() - pass next pulse/space to decoders with some processing
 149  * @dev:        the struct rc_dev device descriptor
 150  * @type:       the type of the event that has occurred
 151  *
 152  * This routine (which may be called from an interrupt context) works
 153  * in similar manner to ir_raw_event_store_edge.
 154  * This routine is intended for devices with limited internal buffer
 155  * It automerges samples of same type, and handles timeouts. Returns non-zero
 156  * if the event was added, and zero if the event was ignored due to idle
 157  * processing.
 158  */
 159 int ir_raw_event_store_with_filter(struct rc_dev *dev, struct ir_raw_event *ev)
 160 {
 161         if (!dev->raw)
 162                 return -EINVAL;
 163
 164         /* Ignore spaces in idle mode */
 165         if (dev->idle && !ev->pulse)
 166                 return 0;
 167         else if (dev->idle)
 168                 ir_raw_event_set_idle(dev, false);
 169
 170         if (!dev->raw->this_ev.duration)
 171                 dev->raw->this_ev = *ev;
 172         else if (ev->pulse == dev->raw->this_ev.pulse)
 173                 dev->raw->this_ev.duration += ev->duration;
 174         else {
 175                 ir_raw_event_store(dev, &dev->raw->this_ev);
 176                 dev->raw->this_ev = *ev;
 177         }
 178
 179         /* Enter idle mode if nessesary */
 180         if (!ev->pulse && dev->timeout &&
 181             dev->raw->this_ev.duration >= dev->timeout)
 182                 ir_raw_event_set_idle(dev, true);
 183
 184         return 1;
 185 }
 186 EXPORT_SYMBOL_GPL(ir_raw_event_store_with_filter);
 187
 188 /**
 189  * ir_raw_event_set_idle() - provide hint to rc-core when the device is idle or not
 190  * @dev:        the struct rc_dev device descriptor
 191  * @idle:       whether the device is idle or not
 192  */
 193 void ir_raw_event_set_idle(struct rc_dev *dev, bool idle)
 194 {
 195         if (!dev->raw)
 196                 return;
 197
 198         IR_dprintk(2, "%s idle mode\n", idle ? "enter" : "leave");
 199
 200         if (idle) {
 201                 dev->raw->this_ev.timeout = true;
 202                 ir_raw_event_store(dev, &dev->raw->this_ev);
 203                 init_ir_raw_event(&dev->raw->this_ev);
 204         }
 205
 206         if (dev->s_idle)
 207                 dev->s_idle(dev, idle);
 208
 209         dev->idle = idle;
 210 }
 211 EXPORT_SYMBOL_GPL(ir_raw_event_set_idle);
 212
 213 /**
 214  * ir_raw_event_handle() - schedules the decoding of stored ir data
 215  * @dev:        the struct rc_dev device descriptor
 216  *
 217  * This routine will tell rc-core to start decoding stored ir data.
 218  */
 219 void ir_raw_event_handle(struct rc_dev *dev)
 220 {
 221         unsigned long flags;
 222
 223         if (!dev->raw)
 224                 return;
 225
 226         spin_lock_irqsave(&dev->raw->lock, flags);
 227         wake_up_process(dev->raw->thread);
 228         spin_unlock_irqrestore(&dev->raw->lock, flags);
 229 }
 230 EXPORT_SYMBOL_GPL(ir_raw_event_handle);
 231
 232 /* used internally by the sysfs interface */
 233 u64
 234 ir_raw_get_allowed_protocols(void)
 235 {
 236         return atomic64_read(&available_protocols);
 237 }
 238
 239 static int change_protocol(struct rc_dev *dev, u64 *rc_type)
 240 {
 241         /* the caller will update dev->enabled_protocols */
 242         return 0;
 243 }
 244
 245 static void ir_raw_disable_protocols(struct rc_dev *dev, u64 protocols)
 246 {
 247         mutex_lock(&dev->lock);
 248         dev->enabled_protocols &= ~protocols;
 249         dev->enabled_wakeup_protocols &= ~protocols;
 250         mutex_unlock(&dev->lock);
 251 }
 252
 253 /*
 254  * Used to (un)register raw event clients
 255  */
 256 int ir_raw_event_register(struct rc_dev *dev)
 257 {
 258         int rc;
 259         struct ir_raw_handler *handler;
 260
 261         if (!dev)
 262                 return -EINVAL;
 263
 264         dev->raw = kzalloc(sizeof(*dev->raw), GFP_KERNEL);
 265         if (!dev->raw)
 266                 return -ENOMEM;
 267
 268         dev->raw->dev = dev;
 269         dev->change_protocol = change_protocol;
 270         INIT_KFIFO(dev->raw->kfifo);
 271
 272         spin_lock_init(&dev->raw->lock);
 273         dev->raw->thread = kthread_run(ir_raw_event_thread, dev->raw,
 274                                        "rc%u", dev->minor);
 275
 276         if (IS_ERR(dev->raw->thread)) {
 277                 rc = PTR_ERR(dev->raw->thread);
 278                 goto out;
 279         }
 280
 281         mutex_lock(&ir_raw_handler_lock);
 282         list_add_tail(&dev->raw->list, &ir_raw_client_list);
 283         list_for_each_entry(handler, &ir_raw_handler_list, list)
 284                 if (handler->raw_register)
 285                         handler->raw_register(dev);
 286         mutex_unlock(&ir_raw_handler_lock);
 287
 288         return 0;
 289
 290 out:
 291         kfree(dev->raw);
 292         dev->raw = NULL;
 293         return rc;
 294 }
 295
 296 void ir_raw_event_unregister(struct rc_dev *dev)
 297 {
 298         struct ir_raw_handler *handler;
 299
 300         if (!dev || !dev->raw)
 301                 return;
 302
 303         kthread_stop(dev->raw->thread);
 304
 305         mutex_lock(&ir_raw_handler_lock);
 306         list_del(&dev->raw->list);
 307         list_for_each_entry(handler, &ir_raw_handler_list, list)
 308                 if (handler->raw_unregister)
 309                         handler->raw_unregister(dev);
 310         mutex_unlock(&ir_raw_handler_lock);
 311
 312         kfree(dev->raw);
 313         dev->raw = NULL;
 314 }
 315
 316 /*
 317  * Extension interface - used to register the IR decoders
 318  */
 319
 320 int ir_raw_handler_register(struct ir_raw_handler *ir_raw_handler)
 321 {
 322         struct ir_raw_event_ctrl *raw;
 323
 324         mutex_lock(&ir_raw_handler_lock);
 325         list_add_tail(&ir_raw_handler->list, &ir_raw_handler_list);
 326         if (ir_raw_handler->raw_register)
 327                 list_for_each_entry(raw, &ir_raw_client_list, list)
 328                         ir_raw_handler->raw_register(raw->dev);
 329         atomic64_or(ir_raw_handler->protocols, &available_protocols);
 330         mutex_unlock(&ir_raw_handler_lock);
 331
 332         return 0;
 333 }
 334 EXPORT_SYMBOL(ir_raw_handler_register);
 335
 336 void ir_raw_handler_unregister(struct ir_raw_handler *ir_raw_handler)
 337 {
 338         struct ir_raw_event_ctrl *raw;
 339         u64 protocols = ir_raw_handler->protocols;
 340
 341         mutex_lock(&ir_raw_handler_lock);
 342         list_del(&ir_raw_handler->list);
 343         list_for_each_entry(raw, &ir_raw_client_list, list) {
 344                 ir_raw_disable_protocols(raw->dev, protocols);
 345                 if (ir_raw_handler->raw_unregister)
 346                         ir_raw_handler->raw_unregister(raw->dev);
 347         }
 348         atomic64_andnot(protocols, &available_protocols);
 349         mutex_unlock(&ir_raw_handler_lock);
 350 }
 351 EXPORT_SYMBOL(ir_raw_handler_unregister);