drivers/media/IR/ir-raw-event.c

   1 /* ir-raw-event.c - handle IR Pulse/Space event
   2  *
   3  * Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
   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/workqueue.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/sched.h>
  18 #include "ir-core-priv.h"
  19
  20 /* Define the max number of pulse/space transitions to buffer */
  21 #define MAX_IR_EVENT_SIZE      512
  22
  23 /* Used to handle IR raw handler extensions */
  24 static LIST_HEAD(ir_raw_handler_list);
  25 static DEFINE_SPINLOCK(ir_raw_handler_lock);
  26
  27 /**
  28  * RUN_DECODER()        - runs an operation on all IR decoders
  29  * @ops:        IR raw handler operation to be called
  30  * @arg:        arguments to be passed to the callback
  31  *
  32  * Calls ir_raw_handler::ops for all registered IR handlers. It prevents
  33  * new decode addition/removal while running, by locking ir_raw_handler_lock
  34  * mutex. If an error occurs, it stops the ops. Otherwise, it returns a sum
  35  * of the return codes.
  36  */
  37 #define RUN_DECODER(ops, ...) ({                                            \
  38         struct ir_raw_handler           *_ir_raw_handler;                   \
  39         int _sumrc = 0, _rc;                                                \
  40         spin_lock(&ir_raw_handler_lock);                                    \
  41         list_for_each_entry(_ir_raw_handler, &ir_raw_handler_list, list) {  \
  42                 if (_ir_raw_handler->ops) {                                 \
  43                         _rc = _ir_raw_handler->ops(__VA_ARGS__);            \
  44                         if (_rc < 0)                                        \
  45                                 break;                                      \
  46                         _sumrc += _rc;                                      \
  47                 }                                                           \
  48         }                                                                   \
  49         spin_unlock(&ir_raw_handler_lock);                                  \
  50         _sumrc;                                                             \
  51 })
  52
  53 #ifdef MODULE
  54 /* Used to load the decoders */
  55 static struct work_struct wq_load;
  56 #endif
  57
  58 static void ir_raw_event_work(struct work_struct *work)
  59 {
  60         struct ir_raw_event ev;
  61         struct ir_raw_event_ctrl *raw =
  62                 container_of(work, struct ir_raw_event_ctrl, rx_work);
  63
  64         while (kfifo_out(&raw->kfifo, &ev, sizeof(ev)) == sizeof(ev))
  65                 RUN_DECODER(decode, raw->input_dev, ev);
  66 }
  67
  68 int ir_raw_event_register(struct input_dev *input_dev)
  69 {
  70         struct ir_input_dev *ir = input_get_drvdata(input_dev);
  71         int rc;
  72
  73         ir->raw = kzalloc(sizeof(*ir->raw), GFP_KERNEL);
  74         if (!ir->raw)
  75                 return -ENOMEM;
  76
  77         ir->raw->input_dev = input_dev;
  78         INIT_WORK(&ir->raw->rx_work, ir_raw_event_work);
  79
  80         rc = kfifo_alloc(&ir->raw->kfifo, sizeof(s64) * MAX_IR_EVENT_SIZE,
  81                          GFP_KERNEL);
  82         if (rc < 0) {
  83                 kfree(ir->raw);
  84                 ir->raw = NULL;
  85                 return rc;
  86         }
  87
  88         rc = RUN_DECODER(raw_register, input_dev);
  89         if (rc < 0) {
  90                 kfifo_free(&ir->raw->kfifo);
  91                 kfree(ir->raw);
  92                 ir->raw = NULL;
  93                 return rc;
  94         }
  95
  96         return rc;
  97 }
  98
  99 void ir_raw_event_unregister(struct input_dev *input_dev)
 100 {
 101         struct ir_input_dev *ir = input_get_drvdata(input_dev);
 102
 103         if (!ir->raw)
 104                 return;
 105
 106         cancel_work_sync(&ir->raw->rx_work);
 107         RUN_DECODER(raw_unregister, input_dev);
 108
 109         kfifo_free(&ir->raw->kfifo);
 110         kfree(ir->raw);
 111         ir->raw = NULL;
 112 }
 113
 114 /**
 115  * ir_raw_event_store() - pass a pulse/space duration to the raw ir decoders
 116  * @input_dev:  the struct input_dev device descriptor
 117  * @ev:         the struct ir_raw_event descriptor of the pulse/space
 118  *
 119  * This routine (which may be called from an interrupt context) stores a
 120  * pulse/space duration for the raw ir decoding state machines. Pulses are
 121  * signalled as positive values and spaces as negative values. A zero value
 122  * will reset the decoding state machines.
 123  */
 124 int ir_raw_event_store(struct input_dev *input_dev, struct ir_raw_event *ev)
 125 {
 126         struct ir_input_dev *ir = input_get_drvdata(input_dev);
 127
 128         if (!ir->raw)
 129                 return -EINVAL;
 130
 131         if (kfifo_in(&ir->raw->kfifo, ev, sizeof(*ev)) != sizeof(*ev))
 132                 return -ENOMEM;
 133
 134         return 0;
 135 }
 136 EXPORT_SYMBOL_GPL(ir_raw_event_store);
 137
 138 /**
 139  * ir_raw_event_store_edge() - notify raw ir decoders of the start of a pulse/space
 140  * @input_dev:  the struct input_dev device descriptor
 141  * @type:       the type of the event that has occurred
 142  *
 143  * This routine (which may be called from an interrupt context) is used to
 144  * store the beginning of an ir pulse or space (or the start/end of ir
 145  * reception) for the raw ir decoding state machines. This is used by
 146  * hardware which does not provide durations directly but only interrupts
 147  * (or similar events) on state change.
 148  */
 149 int ir_raw_event_store_edge(struct input_dev *input_dev, enum raw_event_type type)
 150 {
 151         struct ir_input_dev     *ir = input_get_drvdata(input_dev);
 152         ktime_t                 now;
 153         s64                     delta; /* ns */
 154         struct ir_raw_event     ev;
 155         int                     rc = 0;
 156
 157         if (!ir->raw)
 158                 return -EINVAL;
 159
 160         now = ktime_get();
 161         delta = ktime_to_ns(ktime_sub(now, ir->raw->last_event));
 162
 163         /* Check for a long duration since last event or if we're
 164          * being called for the first time, note that delta can't
 165          * possibly be negative.
 166          */
 167         ev.duration = 0;
 168         if (delta > IR_MAX_DURATION || !ir->raw->last_type)
 169                 type |= IR_START_EVENT;
 170         else
 171                 ev.duration = delta;
 172
 173         if (type & IR_START_EVENT)
 174                 ir_raw_event_reset(input_dev);
 175         else if (ir->raw->last_type & IR_SPACE) {
 176                 ev.pulse = false;
 177                 rc = ir_raw_event_store(input_dev, &ev);
 178         } else if (ir->raw->last_type & IR_PULSE) {
 179                 ev.pulse = true;
 180                 rc = ir_raw_event_store(input_dev, &ev);
 181         } else
 182                 return 0;
 183
 184         ir->raw->last_event = now;
 185         ir->raw->last_type = type;
 186         return rc;
 187 }
 188 EXPORT_SYMBOL_GPL(ir_raw_event_store_edge);
 189
 190 /**
 191  * ir_raw_event_handle() - schedules the decoding of stored ir data
 192  * @input_dev:  the struct input_dev device descriptor
 193  *
 194  * This routine will signal the workqueue to start decoding stored ir data.
 195  */
 196 void ir_raw_event_handle(struct input_dev *input_dev)
 197 {
 198         struct ir_input_dev *ir = input_get_drvdata(input_dev);
 199
 200         if (!ir->raw)
 201                 return;
 202
 203         schedule_work(&ir->raw->rx_work);
 204 }
 205 EXPORT_SYMBOL_GPL(ir_raw_event_handle);
 206
 207 /*
 208  * Extension interface - used to register the IR decoders
 209  */
 210
 211 int ir_raw_handler_register(struct ir_raw_handler *ir_raw_handler)
 212 {
 213         spin_lock(&ir_raw_handler_lock);
 214         list_add_tail(&ir_raw_handler->list, &ir_raw_handler_list);
 215         spin_unlock(&ir_raw_handler_lock);
 216         return 0;
 217 }
 218 EXPORT_SYMBOL(ir_raw_handler_register);
 219
 220 void ir_raw_handler_unregister(struct ir_raw_handler *ir_raw_handler)
 221 {
 222         spin_lock(&ir_raw_handler_lock);
 223         list_del(&ir_raw_handler->list);
 224         spin_unlock(&ir_raw_handler_lock);
 225 }
 226 EXPORT_SYMBOL(ir_raw_handler_unregister);
 227
 228 #ifdef MODULE
 229 static void init_decoders(struct work_struct *work)
 230 {
 231         /* Load the decoder modules */
 232
 233         load_nec_decode();
 234         load_rc5_decode();
 235         load_rc6_decode();
 236         load_jvc_decode();
 237         load_sony_decode();
 238
 239         /* If needed, we may later add some init code. In this case,
 240            it is needed to change the CONFIG_MODULE test at ir-core.h
 241          */
 242 }
 243 #endif
 244
 245 void ir_raw_init(void)
 246 {
 247 #ifdef MODULE
 248         INIT_WORK(&wq_load, init_decoders);
 249         schedule_work(&wq_load);
 250 #endif
 251 }