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/init.h>
  25 #include <linux/module.h>
  26 #include <linux/sched.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/device.h>
  29 #include <linux/blkdev.h>
  30 #include <linux/err.h>
  31 #include <linux/delay.h>
  32 #include <linux/io.h>
  33 #include <mach/mailbox.h>
  34
  35 static struct omap_mbox *mboxes;
  36 static DEFINE_RWLOCK(mboxes_lock);
  37
  38 /*
  39  * Mailbox sequence bit API
  40  */
  41 #if defined(CONFIG_ARCH_OMAP1)
  42 #  define MBOX_USE_SEQ_BIT
  43 #elif defined(CONFIG_ARCH_OMAP2)
  44 #  define MBOX_USE_SEQ_BIT
  45 #endif
  46
  47 #ifdef MBOX_USE_SEQ_BIT
  48 /* seq_rcv should be initialized with any value other than
  49  * 0 and 1 << 31, to allow either value for the first
  50  * message.  */
  51 static inline void mbox_seq_init(struct omap_mbox *mbox)
  52 {
  53         /* any value other than 0 and 1 << 31 */
  54         mbox->seq_rcv = 0xffffffff;
  55 }
  56
  57 static inline void mbox_seq_toggle(struct omap_mbox *mbox, mbox_msg_t * msg)
  58 {
  59         /* add seq_snd to msg */
  60         *msg = (*msg & 0x7fffffff) | mbox->seq_snd;
  61         /* flip seq_snd */
  62         mbox->seq_snd ^= 1 << 31;
  63 }
  64
  65 static inline int mbox_seq_test(struct omap_mbox *mbox, mbox_msg_t msg)
  66 {
  67         mbox_msg_t seq = msg & (1 << 31);
  68         if (seq == mbox->seq_rcv)
  69                 return -1;
  70         mbox->seq_rcv = seq;
  71         return 0;
  72 }
  73 #else
  74 static inline void mbox_seq_init(struct omap_mbox *mbox)
  75 {
  76 }
  77 static inline void mbox_seq_toggle(struct omap_mbox *mbox, mbox_msg_t * msg)
  78 {
  79 }
  80 static inline int mbox_seq_test(struct omap_mbox *mbox, mbox_msg_t msg)
  81 {
  82         return 0;
  83 }
  84 #endif
  85
  86 /* Mailbox FIFO handle functions */
  87 static inline mbox_msg_t mbox_fifo_read(struct omap_mbox *mbox)
  88 {
  89         return mbox->ops->fifo_read(mbox);
  90 }
  91 static inline void mbox_fifo_write(struct omap_mbox *mbox, mbox_msg_t msg)
  92 {
  93         mbox->ops->fifo_write(mbox, msg);
  94 }
  95 static inline int mbox_fifo_empty(struct omap_mbox *mbox)
  96 {
  97         return mbox->ops->fifo_empty(mbox);
  98 }
  99 static inline int mbox_fifo_full(struct omap_mbox *mbox)
 100 {
 101         return mbox->ops->fifo_full(mbox);
 102 }
 103
 104 /* Mailbox IRQ handle functions */
 105 static inline void enable_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
 106 {
 107         mbox->ops->enable_irq(mbox, irq);
 108 }
 109 static inline void disable_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
 110 {
 111         mbox->ops->disable_irq(mbox, irq);
 112 }
 113 static inline void ack_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
 114 {
 115         if (mbox->ops->ack_irq)
 116                 mbox->ops->ack_irq(mbox, irq);
 117 }
 118 static inline int is_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
 119 {
 120         return mbox->ops->is_irq(mbox, irq);
 121 }
 122
 123 /* Mailbox Sequence Bit function */
 124 void omap_mbox_init_seq(struct omap_mbox *mbox)
 125 {
 126         mbox_seq_init(mbox);
 127 }
 128 EXPORT_SYMBOL(omap_mbox_init_seq);
 129
 130 /*
 131  * message sender
 132  */
 133 static int __mbox_msg_send(struct omap_mbox *mbox, mbox_msg_t msg, void *arg)
 134 {
 135         int ret = 0, i = 1000;
 136
 137         while (mbox_fifo_full(mbox)) {
 138                 if (mbox->ops->type == OMAP_MBOX_TYPE2)
 139                         return -1;
 140                 if (--i == 0)
 141                         return -1;
 142                 udelay(1);
 143         }
 144
 145         if (arg && mbox->txq->callback) {
 146                 ret = mbox->txq->callback(arg);
 147                 if (ret)
 148                         goto out;
 149         }
 150
 151         mbox_seq_toggle(mbox, &msg);
 152         mbox_fifo_write(mbox, msg);
 153  out:
 154         return ret;
 155 }
 156
 157 int omap_mbox_msg_send(struct omap_mbox *mbox, mbox_msg_t msg, void* arg)
 158 {
 159         struct request *rq;
 160         struct request_queue *q = mbox->txq->queue;
 161         int ret = 0;
 162
 163         rq = blk_get_request(q, WRITE, GFP_ATOMIC);
 164         if (unlikely(!rq)) {
 165                 ret = -ENOMEM;
 166                 goto fail;
 167         }
 168
 169         rq->data = (void *)msg;
 170         blk_insert_request(q, rq, 0, arg);
 171
 172         schedule_work(&mbox->txq->work);
 173  fail:
 174         return ret;
 175 }
 176 EXPORT_SYMBOL(omap_mbox_msg_send);
 177
 178 static void mbox_tx_work(struct work_struct *work)
 179 {
 180         int ret;
 181         struct request *rq;
 182         struct omap_mbox_queue *mq = container_of(work,
 183                                 struct omap_mbox_queue, work);
 184         struct omap_mbox *mbox = mq->queue->queuedata;
 185         struct request_queue *q = mbox->txq->queue;
 186
 187         while (1) {
 188                 spin_lock(q->queue_lock);
 189                 rq = elv_next_request(q);
 190                 spin_unlock(q->queue_lock);
 191
 192                 if (!rq)
 193                         break;
 194
 195                 ret = __mbox_msg_send(mbox, (mbox_msg_t) rq->data, rq->special);
 196                 if (ret) {
 197                         enable_mbox_irq(mbox, IRQ_TX);
 198                         return;
 199                 }
 200
 201                 spin_lock(q->queue_lock);
 202                 if (__blk_end_request(rq, 0, 0))
 203                         BUG();
 204                 spin_unlock(q->queue_lock);
 205         }
 206 }
 207
 208 /*
 209  * Message receiver(workqueue)
 210  */
 211 static void mbox_rx_work(struct work_struct *work)
 212 {
 213         struct omap_mbox_queue *mq =
 214                         container_of(work, struct omap_mbox_queue, work);
 215         struct omap_mbox *mbox = mq->queue->queuedata;
 216         struct request_queue *q = mbox->rxq->queue;
 217         struct request *rq;
 218         mbox_msg_t msg;
 219         unsigned long flags;
 220
 221         if (mbox->rxq->callback == NULL) {
 222                 sysfs_notify(&mbox->dev->kobj, NULL, "mbox");
 223                 return;
 224         }
 225
 226         while (1) {
 227                 spin_lock_irqsave(q->queue_lock, flags);
 228                 rq = elv_next_request(q);
 229                 spin_unlock_irqrestore(q->queue_lock, flags);
 230                 if (!rq)
 231                         break;
 232
 233                 msg = (mbox_msg_t) rq->data;
 234
 235                 if (blk_end_request(rq, 0, 0))
 236                         BUG();
 237
 238                 mbox->rxq->callback((void *)msg);
 239         }
 240 }
 241
 242 /*
 243  * Mailbox interrupt handler
 244  */
 245 static void mbox_txq_fn(struct request_queue * q)
 246 {
 247 }
 248
 249 static void mbox_rxq_fn(struct request_queue * q)
 250 {
 251 }
 252
 253 static void __mbox_tx_interrupt(struct omap_mbox *mbox)
 254 {
 255         disable_mbox_irq(mbox, IRQ_TX);
 256         ack_mbox_irq(mbox, IRQ_TX);
 257         schedule_work(&mbox->txq->work);
 258 }
 259
 260 static void __mbox_rx_interrupt(struct omap_mbox *mbox)
 261 {
 262         struct request *rq;
 263         mbox_msg_t msg;
 264         struct request_queue *q = mbox->rxq->queue;
 265
 266         disable_mbox_irq(mbox, IRQ_RX);
 267
 268         while (!mbox_fifo_empty(mbox)) {
 269                 rq = blk_get_request(q, WRITE, GFP_ATOMIC);
 270                 if (unlikely(!rq))
 271                         goto nomem;
 272
 273                 msg = mbox_fifo_read(mbox);
 274                 rq->data = (void *)msg;
 275
 276                 if (unlikely(mbox_seq_test(mbox, msg))) {
 277                         pr_info("mbox: Illegal seq bit!(%08x)\n", msg);
 278                         if (mbox->err_notify)
 279                                 mbox->err_notify();
 280                 }
 281
 282                 blk_insert_request(q, rq, 0, NULL);
 283                 if (mbox->ops->type == OMAP_MBOX_TYPE1)
 284                         break;
 285         }
 286
 287         /* no more messages in the fifo. clear IRQ source. */
 288         ack_mbox_irq(mbox, IRQ_RX);
 289         enable_mbox_irq(mbox, IRQ_RX);
 290 nomem:
 291         schedule_work(&mbox->rxq->work);
 292 }
 293
 294 static irqreturn_t mbox_interrupt(int irq, void *p)
 295 {
 296         struct omap_mbox *mbox = p;
 297
 298         if (is_mbox_irq(mbox, IRQ_TX))
 299                 __mbox_tx_interrupt(mbox);
 300
 301         if (is_mbox_irq(mbox, IRQ_RX))
 302                 __mbox_rx_interrupt(mbox);
 303
 304         return IRQ_HANDLED;
 305 }
 306
 307 /*
 308  * sysfs files
 309  */
 310 static ssize_t
 311 omap_mbox_write(struct device *dev, struct device_attribute *attr,
 312                 const char * buf, size_t count)
 313 {
 314         int ret;
 315         mbox_msg_t *p = (mbox_msg_t *)buf;
 316         struct omap_mbox *mbox = dev_get_drvdata(dev);
 317
 318         for (; count >= sizeof(mbox_msg_t); count -= sizeof(mbox_msg_t)) {
 319                 ret = omap_mbox_msg_send(mbox, be32_to_cpu(*p), NULL);
 320                 if (ret)
 321                         return -EAGAIN;
 322                 p++;
 323         }
 324
 325         return (size_t)((char *)p - buf);
 326 }
 327
 328 static ssize_t
 329 omap_mbox_read(struct device *dev, struct device_attribute *attr, char *buf)
 330 {
 331         unsigned long flags;
 332         struct request *rq;
 333         mbox_msg_t *p = (mbox_msg_t *) buf;
 334         struct omap_mbox *mbox = dev_get_drvdata(dev);
 335         struct request_queue *q = mbox->rxq->queue;
 336
 337         while (1) {
 338                 spin_lock_irqsave(q->queue_lock, flags);
 339                 rq = elv_next_request(q);
 340                 spin_unlock_irqrestore(q->queue_lock, flags);
 341
 342                 if (!rq)
 343                         break;
 344
 345                 *p = (mbox_msg_t) rq->data;
 346
 347                 if (blk_end_request(rq, 0, 0))
 348                         BUG();
 349
 350                 if (unlikely(mbox_seq_test(mbox, *p))) {
 351                         pr_info("mbox: Illegal seq bit!(%08x) ignored\n", *p);
 352                         continue;
 353                 }
 354                 p++;
 355         }
 356
 357         pr_debug("%02x %02x %02x %02x\n", buf[0], buf[1], buf[2], buf[3]);
 358
 359         return (size_t) ((char *)p - buf);
 360 }
 361
 362 static DEVICE_ATTR(mbox, S_IRUGO | S_IWUSR, omap_mbox_read, omap_mbox_write);
 363
 364 static ssize_t mbox_show(struct class *class, char *buf)
 365 {
 366         return sprintf(buf, "mbox");
 367 }
 368
 369 static CLASS_ATTR(mbox, S_IRUGO, mbox_show, NULL);
 370
 371 static struct class omap_mbox_class = {
 372         .name = "omap-mailbox",
 373 };
 374
 375 static struct omap_mbox_queue *mbox_queue_alloc(struct omap_mbox *mbox,
 376                                         request_fn_proc * proc,
 377                                         void (*work) (struct work_struct *))
 378 {
 379         struct request_queue *q;
 380         struct omap_mbox_queue *mq;
 381
 382         mq = kzalloc(sizeof(struct omap_mbox_queue), GFP_KERNEL);
 383         if (!mq)
 384                 return NULL;
 385
 386         spin_lock_init(&mq->lock);
 387
 388         q = blk_init_queue(proc, &mq->lock);
 389         if (!q)
 390                 goto error;
 391         q->queuedata = mbox;
 392         mq->queue = q;
 393
 394         INIT_WORK(&mq->work, work);
 395
 396         return mq;
 397 error:
 398         kfree(mq);
 399         return NULL;
 400 }
 401
 402 static void mbox_queue_free(struct omap_mbox_queue *q)
 403 {
 404         blk_cleanup_queue(q->queue);
 405         kfree(q);
 406 }
 407
 408 static int omap_mbox_init(struct omap_mbox *mbox)
 409 {
 410         int ret;
 411         struct omap_mbox_queue *mq;
 412
 413         if (likely(mbox->ops->startup)) {
 414                 ret = mbox->ops->startup(mbox);
 415                 if (unlikely(ret))
 416                         return ret;
 417         }
 418
 419         ret = request_irq(mbox->irq, mbox_interrupt, IRQF_DISABLED,
 420                                 mbox->name, mbox);
 421         if (unlikely(ret)) {
 422                 printk(KERN_ERR
 423                         "failed to register mailbox interrupt:%d\n", ret);
 424                 goto fail_request_irq;
 425         }
 426
 427         mq = mbox_queue_alloc(mbox, mbox_txq_fn, mbox_tx_work);
 428         if (!mq) {
 429                 ret = -ENOMEM;
 430                 goto fail_alloc_txq;
 431         }
 432         mbox->txq = mq;
 433
 434         mq = mbox_queue_alloc(mbox, mbox_rxq_fn, mbox_rx_work);
 435         if (!mq) {
 436                 ret = -ENOMEM;
 437                 goto fail_alloc_rxq;
 438         }
 439         mbox->rxq = mq;
 440
 441         return 0;
 442
 443  fail_alloc_rxq:
 444         mbox_queue_free(mbox->txq);
 445  fail_alloc_txq:
 446         free_irq(mbox->irq, mbox);
 447  fail_request_irq:
 448         if (unlikely(mbox->ops->shutdown))
 449                 mbox->ops->shutdown(mbox);
 450
 451         return ret;
 452 }
 453
 454 static void omap_mbox_fini(struct omap_mbox *mbox)
 455 {
 456         mbox_queue_free(mbox->txq);
 457         mbox_queue_free(mbox->rxq);
 458
 459         free_irq(mbox->irq, mbox);
 460
 461         if (unlikely(mbox->ops->shutdown))
 462                 mbox->ops->shutdown(mbox);
 463 }
 464
 465 static struct omap_mbox **find_mboxes(const char *name)
 466 {
 467         struct omap_mbox **p;
 468
 469         for (p = &mboxes; *p; p = &(*p)->next) {
 470                 if (strcmp((*p)->name, name) == 0)
 471                         break;
 472         }
 473
 474         return p;
 475 }
 476
 477 struct omap_mbox *omap_mbox_get(const char *name)
 478 {
 479         struct omap_mbox *mbox;
 480         int ret;
 481
 482         read_lock(&mboxes_lock);
 483         mbox = *(find_mboxes(name));
 484         if (mbox == NULL) {
 485                 read_unlock(&mboxes_lock);
 486                 return ERR_PTR(-ENOENT);
 487         }
 488
 489         read_unlock(&mboxes_lock);
 490
 491         ret = omap_mbox_init(mbox);
 492         if (ret)
 493                 return ERR_PTR(-ENODEV);
 494
 495         return mbox;
 496 }
 497 EXPORT_SYMBOL(omap_mbox_get);
 498
 499 void omap_mbox_put(struct omap_mbox *mbox)
 500 {
 501         omap_mbox_fini(mbox);
 502 }
 503 EXPORT_SYMBOL(omap_mbox_put);
 504
 505 int omap_mbox_register(struct device *parent, struct omap_mbox *mbox)
 506 {
 507         int ret = 0;
 508         struct omap_mbox **tmp;
 509
 510         if (!mbox)
 511                 return -EINVAL;
 512         if (mbox->next)
 513                 return -EBUSY;
 514
 515         mbox->dev = device_create(&omap_mbox_class,
 516                                   parent, 0, mbox, "%s", mbox->name);
 517         if (IS_ERR(mbox->dev))
 518                 return PTR_ERR(mbox->dev);
 519
 520         ret = device_create_file(mbox->dev, &dev_attr_mbox);
 521         if (ret)
 522                 goto err_sysfs;
 523
 524         write_lock(&mboxes_lock);
 525         tmp = find_mboxes(mbox->name);
 526         if (*tmp) {
 527                 ret = -EBUSY;
 528                 write_unlock(&mboxes_lock);
 529                 goto err_find;
 530         }
 531         *tmp = mbox;
 532         write_unlock(&mboxes_lock);
 533
 534         return 0;
 535
 536 err_find:
 537         device_remove_file(mbox->dev, &dev_attr_mbox);
 538 err_sysfs:
 539         device_unregister(mbox->dev);
 540         return ret;
 541 }
 542 EXPORT_SYMBOL(omap_mbox_register);
 543
 544 int omap_mbox_unregister(struct omap_mbox *mbox)
 545 {
 546         struct omap_mbox **tmp;
 547
 548         write_lock(&mboxes_lock);
 549         tmp = &mboxes;
 550         while (*tmp) {
 551                 if (mbox == *tmp) {
 552                         *tmp = mbox->next;
 553                         mbox->next = NULL;
 554                         write_unlock(&mboxes_lock);
 555                         device_remove_file(mbox->dev, &dev_attr_mbox);
 556                         device_unregister(mbox->dev);
 557                         return 0;
 558                 }
 559                 tmp = &(*tmp)->next;
 560         }
 561         write_unlock(&mboxes_lock);
 562
 563         return -EINVAL;
 564 }
 565 EXPORT_SYMBOL(omap_mbox_unregister);
 566
 567 static int __init omap_mbox_class_init(void)
 568 {
 569         int ret = class_register(&omap_mbox_class);
 570         if (!ret)
 571                 ret = class_create_file(&omap_mbox_class, &class_attr_mbox);
 572
 573         return ret;
 574 }
 575
 576 static void __exit omap_mbox_class_exit(void)
 577 {
 578         class_remove_file(&omap_mbox_class, &class_attr_mbox);
 579         class_unregister(&omap_mbox_class);
 580 }
 581
 582 subsys_initcall(omap_mbox_class_init);
 583 module_exit(omap_mbox_class_exit);
 584
 585 MODULE_LICENSE("GPL v2");
 586 MODULE_DESCRIPTION("omap mailbox: interrupt driven messaging");
 587 MODULE_AUTHOR("Toshihiro Kobayashi and Hiroshi DOYU");