arch/arm/plat-omap/mailbox.c

   1 /*
   2  * OMAP mailbox driver
   3  *
   4  * Copyright (C) 2006-2009 Nokia Corporation. All rights reserved.
   5  *
   6  * Contact: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * version 2 as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  20  * 02110-1301 USA
  21  *
  22  */
  23
  24 #include <linux/interrupt.h>
  25 #include <linux/spinlock.h>
  26 #include <linux/mutex.h>
  27 #include <linux/delay.h>
  28 #include <linux/slab.h>
  29 #include <linux/kfifo.h>
  30 #include <linux/err.h>
  31 #include <linux/notifier.h>
  32
  33 #include <plat/mailbox.h>
  34
  35 static struct workqueue_struct *mboxd;
  36 static struct omap_mbox **mboxes;
  37
  38 static int mbox_configured;
  39 static DEFINE_MUTEX(mbox_configured_lock);
  40
  41 static unsigned int mbox_kfifo_size = CONFIG_OMAP_MBOX_KFIFO_SIZE;
  42 module_param(mbox_kfifo_size, uint, S_IRUGO);
  43 MODULE_PARM_DESC(mbox_kfifo_size, "Size of omap's mailbox kfifo (bytes)");
  44
  45 /* Mailbox FIFO handle functions */
  46 static inline mbox_msg_t mbox_fifo_read(struct omap_mbox *mbox)
  47 {
  48         return mbox->ops->fifo_read(mbox);
  49 }
  50 static inline void mbox_fifo_write(struct omap_mbox *mbox, mbox_msg_t msg)
  51 {
  52         mbox->ops->fifo_write(mbox, msg);
  53 }
  54 static inline int mbox_fifo_empty(struct omap_mbox *mbox)
  55 {
  56         return mbox->ops->fifo_empty(mbox);
  57 }
  58 static inline int mbox_fifo_full(struct omap_mbox *mbox)
  59 {
  60         return mbox->ops->fifo_full(mbox);
  61 }
  62
  63 /* Mailbox IRQ handle functions */
  64 static inline void ack_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
  65 {
  66         if (mbox->ops->ack_irq)
  67                 mbox->ops->ack_irq(mbox, irq);
  68 }
  69 static inline int is_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
  70 {
  71         return mbox->ops->is_irq(mbox, irq);
  72 }
  73
  74 /*
  75  * message sender
  76  */
  77 static int __mbox_poll_for_space(struct omap_mbox *mbox)
  78 {
  79         int ret = 0, i = 1000;
  80
  81         while (mbox_fifo_full(mbox)) {
  82                 if (mbox->ops->type == OMAP_MBOX_TYPE2)
  83                         return -1;
  84                 if (--i == 0)
  85                         return -1;
  86                 udelay(1);
  87         }
  88         return ret;
  89 }
  90
  91 int omap_mbox_msg_send(struct omap_mbox *mbox, mbox_msg_t msg)
  92 {
  93         struct omap_mbox_queue *mq = mbox->txq;
  94         int ret = 0, len;
  95
  96         spin_lock_bh(&mq->lock);
  97
  98         if (kfifo_avail(&mq->fifo) < sizeof(msg)) {
  99                 ret = -ENOMEM;
 100                 goto out;
 101         }
 102
 103         if (kfifo_is_empty(&mq->fifo) && !__mbox_poll_for_space(mbox)) {
 104                 mbox_fifo_write(mbox, msg);
 105                 goto out;
 106         }
 107
 108         len = kfifo_in(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
 109         WARN_ON(len != sizeof(msg));
 110
 111         tasklet_schedule(&mbox->txq->tasklet);
 112
 113 out:
 114         spin_unlock_bh(&mq->lock);
 115         return ret;
 116 }
 117 EXPORT_SYMBOL(omap_mbox_msg_send);
 118
 119 static void mbox_tx_tasklet(unsigned long tx_data)
 120 {
 121         struct omap_mbox *mbox = (struct omap_mbox *)tx_data;
 122         struct omap_mbox_queue *mq = mbox->txq;
 123         mbox_msg_t msg;
 124         int ret;
 125
 126         while (kfifo_len(&mq->fifo)) {
 127                 if (__mbox_poll_for_space(mbox)) {
 128                         omap_mbox_enable_irq(mbox, IRQ_TX);
 129                         break;
 130                 }
 131
 132                 ret = kfifo_out(&mq->fifo, (unsigned char *)&msg,
 133                                                                 sizeof(msg));
 134                 WARN_ON(ret != sizeof(msg));
 135
 136                 mbox_fifo_write(mbox, msg);
 137         }
 138 }
 139
 140 /*
 141  * Message receiver(workqueue)
 142  */
 143 static void mbox_rx_work(struct work_struct *work)
 144 {
 145         struct omap_mbox_queue *mq =
 146                         container_of(work, struct omap_mbox_queue, work);
 147         mbox_msg_t msg;
 148         int len;
 149
 150         while (kfifo_len(&mq->fifo) >= sizeof(msg)) {
 151                 len = kfifo_out(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
 152                 WARN_ON(len != sizeof(msg));
 153
 154                 blocking_notifier_call_chain(&mq->mbox->notifier, len,
 155                                                                 (void *)msg);
 156                 spin_lock_irq(&mq->lock);
 157                 if (mq->full) {
 158                         mq->full = false;
 159                         omap_mbox_enable_irq(mq->mbox, IRQ_RX);
 160                 }
 161                 spin_unlock_irq(&mq->lock);
 162         }
 163 }
 164
 165 /*
 166  * Mailbox interrupt handler
 167  */
 168 static void __mbox_tx_interrupt(struct omap_mbox *mbox)
 169 {
 170         omap_mbox_disable_irq(mbox, IRQ_TX);
 171         ack_mbox_irq(mbox, IRQ_TX);
 172         tasklet_schedule(&mbox->txq->tasklet);
 173 }
 174
 175 static void __mbox_rx_interrupt(struct omap_mbox *mbox)
 176 {
 177         struct omap_mbox_queue *mq = mbox->rxq;
 178         mbox_msg_t msg;
 179         int len;
 180
 181         while (!mbox_fifo_empty(mbox)) {
 182                 if (unlikely(kfifo_avail(&mq->fifo) < sizeof(msg))) {
 183                         omap_mbox_disable_irq(mbox, IRQ_RX);
 184                         mq->full = true;
 185                         goto nomem;
 186                 }
 187
 188                 msg = mbox_fifo_read(mbox);
 189
 190                 len = kfifo_in(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
 191                 WARN_ON(len != sizeof(msg));
 192
 193                 if (mbox->ops->type == OMAP_MBOX_TYPE1)
 194                         break;
 195         }
 196
 197         /* no more messages in the fifo. clear IRQ source. */
 198         ack_mbox_irq(mbox, IRQ_RX);
 199 nomem:
 200         queue_work(mboxd, &mbox->rxq->work);
 201 }
 202
 203 static irqreturn_t mbox_interrupt(int irq, void *p)
 204 {
 205         struct omap_mbox *mbox = p;
 206
 207         if (is_mbox_irq(mbox, IRQ_TX))
 208                 __mbox_tx_interrupt(mbox);
 209
 210         if (is_mbox_irq(mbox, IRQ_RX))
 211                 __mbox_rx_interrupt(mbox);
 212
 213         return IRQ_HANDLED;
 214 }
 215
 216 static struct omap_mbox_queue *mbox_queue_alloc(struct omap_mbox *mbox,
 217                                         void (*work) (struct work_struct *),
 218                                         void (*tasklet)(unsigned long))
 219 {
 220         struct omap_mbox_queue *mq;
 221
 222         mq = kzalloc(sizeof(struct omap_mbox_queue), GFP_KERNEL);
 223         if (!mq)
 224                 return NULL;
 225
 226         spin_lock_init(&mq->lock);
 227
 228         if (kfifo_alloc(&mq->fifo, mbox_kfifo_size, GFP_KERNEL))
 229                 goto error;
 230
 231         if (work)
 232                 INIT_WORK(&mq->work, work);
 233
 234         if (tasklet)
 235                 tasklet_init(&mq->tasklet, tasklet, (unsigned long)mbox);
 236         return mq;
 237 error:
 238         kfree(mq);
 239         return NULL;
 240 }
 241
 242 static void mbox_queue_free(struct omap_mbox_queue *q)
 243 {
 244         kfifo_free(&q->fifo);
 245         kfree(q);
 246 }
 247
 248 static int omap_mbox_startup(struct omap_mbox *mbox)
 249 {
 250         int ret = 0;
 251         struct omap_mbox_queue *mq;
 252
 253         mutex_lock(&mbox_configured_lock);
 254         if (!mbox_configured++) {
 255                 if (likely(mbox->ops->startup)) {
 256                         ret = mbox->ops->startup(mbox);
 257                         if (unlikely(ret))
 258                                 goto fail_startup;
 259                 } else
 260                         goto fail_startup;
 261         }
 262
 263         if (!mbox->use_count++) {
 264                 ret = request_irq(mbox->irq, mbox_interrupt, IRQF_SHARED,
 265                                                         mbox->name, mbox);
 266                 if (unlikely(ret)) {
 267                         pr_err("failed to register mailbox interrupt:%d\n",
 268                                                                         ret);
 269                         goto fail_request_irq;
 270                 }
 271                 mq = mbox_queue_alloc(mbox, NULL, mbox_tx_tasklet);
 272                 if (!mq) {
 273                         ret = -ENOMEM;
 274                         goto fail_alloc_txq;
 275                 }
 276                 mbox->txq = mq;
 277
 278                 mq = mbox_queue_alloc(mbox, mbox_rx_work, NULL);
 279                 if (!mq) {
 280                         ret = -ENOMEM;
 281                         goto fail_alloc_rxq;
 282                 }
 283                 mbox->rxq = mq;
 284                 mq->mbox = mbox;
 285         }
 286         mutex_unlock(&mbox_configured_lock);
 287         return 0;
 288
 289 fail_alloc_rxq:
 290         mbox_queue_free(mbox->txq);
 291 fail_alloc_txq:
 292         free_irq(mbox->irq, mbox);
 293 fail_request_irq:
 294         if (mbox->ops->shutdown)
 295                 mbox->ops->shutdown(mbox);
 296         mbox->use_count--;
 297 fail_startup:
 298         mbox_configured--;
 299         mutex_unlock(&mbox_configured_lock);
 300         return ret;
 301 }
 302
 303 static void omap_mbox_fini(struct omap_mbox *mbox)
 304 {
 305         mutex_lock(&mbox_configured_lock);
 306
 307         if (!--mbox->use_count) {
 308                 free_irq(mbox->irq, mbox);
 309                 tasklet_kill(&mbox->txq->tasklet);
 310                 flush_work(&mbox->rxq->work);
 311                 mbox_queue_free(mbox->txq);
 312                 mbox_queue_free(mbox->rxq);
 313         }
 314
 315         if (likely(mbox->ops->shutdown)) {
 316                 if (!--mbox_configured)
 317                         mbox->ops->shutdown(mbox);
 318         }
 319
 320         mutex_unlock(&mbox_configured_lock);
 321 }
 322
 323 struct omap_mbox *omap_mbox_get(const char *name, struct notifier_block *nb)
 324 {
 325         struct omap_mbox *mbox;
 326         int ret;
 327
 328         if (!mboxes)
 329                 return ERR_PTR(-EINVAL);
 330
 331         for (mbox = *mboxes; mbox; mbox++)
 332                 if (!strcmp(mbox->name, name))
 333                         break;
 334
 335         if (!mbox)
 336                 return ERR_PTR(-ENOENT);
 337
 338         ret = omap_mbox_startup(mbox);
 339         if (ret)
 340                 return ERR_PTR(-ENODEV);
 341
 342         if (nb)
 343                 blocking_notifier_chain_register(&mbox->notifier, nb);
 344
 345         return mbox;
 346 }
 347 EXPORT_SYMBOL(omap_mbox_get);
 348
 349 void omap_mbox_put(struct omap_mbox *mbox, struct notifier_block *nb)
 350 {
 351         blocking_notifier_chain_unregister(&mbox->notifier, nb);
 352         omap_mbox_fini(mbox);
 353 }
 354 EXPORT_SYMBOL(omap_mbox_put);
 355
 356 static struct class omap_mbox_class = { .name = "mbox", };
 357
 358 int omap_mbox_register(struct device *parent, struct omap_mbox **list)
 359 {
 360         int ret;
 361         int i;
 362
 363         mboxes = list;
 364         if (!mboxes)
 365                 return -EINVAL;
 366
 367         for (i = 0; mboxes[i]; i++) {
 368                 struct omap_mbox *mbox = mboxes[i];
 369                 mbox->dev = device_create(&omap_mbox_class,
 370                                 parent, 0, mbox, "%s", mbox->name);
 371                 if (IS_ERR(mbox->dev)) {
 372                         ret = PTR_ERR(mbox->dev);
 373                         goto err_out;
 374                 }
 375
 376                 BLOCKING_INIT_NOTIFIER_HEAD(&mbox->notifier);
 377         }
 378         return 0;
 379
 380 err_out:
 381         while (i--)
 382                 device_unregister(mboxes[i]->dev);
 383         return ret;
 384 }
 385 EXPORT_SYMBOL(omap_mbox_register);
 386
 387 int omap_mbox_unregister(void)
 388 {
 389         int i;
 390
 391         if (!mboxes)
 392                 return -EINVAL;
 393
 394         for (i = 0; mboxes[i]; i++)
 395                 device_unregister(mboxes[i]->dev);
 396         mboxes = NULL;
 397         return 0;
 398 }
 399 EXPORT_SYMBOL(omap_mbox_unregister);
 400
 401 static int __init omap_mbox_init(void)
 402 {
 403         int err;
 404
 405         err = class_register(&omap_mbox_class);
 406         if (err)
 407                 return err;
 408
 409         mboxd = create_workqueue("mboxd");
 410         if (!mboxd)
 411                 return -ENOMEM;
 412
 413         /* kfifo size sanity check: alignment and minimal size */
 414         mbox_kfifo_size = ALIGN(mbox_kfifo_size, sizeof(mbox_msg_t));
 415         mbox_kfifo_size = max_t(unsigned int, mbox_kfifo_size,
 416                                                         sizeof(mbox_msg_t));
 417
 418         return 0;
 419 }
 420 subsys_initcall(omap_mbox_init);
 421
 422 static void __exit omap_mbox_exit(void)
 423 {
 424         destroy_workqueue(mboxd);
 425         class_unregister(&omap_mbox_class);
 426 }
 427 module_exit(omap_mbox_exit);
 428
 429 MODULE_LICENSE("GPL v2");
 430 MODULE_DESCRIPTION("omap mailbox: interrupt driven messaging");
 431 MODULE_AUTHOR("Toshihiro Kobayashi");
 432 MODULE_AUTHOR("Hiroshi DOYU");