release/src-rt-6.x.4708/linux/linux-2.6.36/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
  32 #include <plat/mailbox.h>
  33
  34 static struct workqueue_struct *mboxd;
  35 static struct omap_mbox **mboxes;
  36 static bool rq_full;
  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(&mq->lock);
  97
  98         if (kfifo_avail(&mq->fifo) < sizeof(msg)) {
  99                 ret = -ENOMEM;
 100                 goto out;
 101         }
 102
 103         len = kfifo_in(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
 104         WARN_ON(len != sizeof(msg));
 105
 106         tasklet_schedule(&mbox->txq->tasklet);
 107
 108 out:
 109         spin_unlock(&mq->lock);
 110         return ret;
 111 }
 112 EXPORT_SYMBOL(omap_mbox_msg_send);
 113
 114 static void mbox_tx_tasklet(unsigned long tx_data)
 115 {
 116         struct omap_mbox *mbox = (struct omap_mbox *)tx_data;
 117         struct omap_mbox_queue *mq = mbox->txq;
 118         mbox_msg_t msg;
 119         int ret;
 120
 121         while (kfifo_len(&mq->fifo)) {
 122                 if (__mbox_poll_for_space(mbox)) {
 123                         omap_mbox_enable_irq(mbox, IRQ_TX);
 124                         break;
 125                 }
 126
 127                 ret = kfifo_out(&mq->fifo, (unsigned char *)&msg,
 128                                                                 sizeof(msg));
 129                 WARN_ON(ret != sizeof(msg));
 130
 131                 mbox_fifo_write(mbox, msg);
 132         }
 133 }
 134
 135 /*
 136  * Message receiver(workqueue)
 137  */
 138 static void mbox_rx_work(struct work_struct *work)
 139 {
 140         struct omap_mbox_queue *mq =
 141                         container_of(work, struct omap_mbox_queue, work);
 142         mbox_msg_t msg;
 143         int len;
 144
 145         while (kfifo_len(&mq->fifo) >= sizeof(msg)) {
 146                 len = kfifo_out(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
 147                 WARN_ON(len != sizeof(msg));
 148
 149                 if (mq->callback)
 150                         mq->callback((void *)msg);
 151         }
 152 }
 153
 154 /*
 155  * Mailbox interrupt handler
 156  */
 157 static void __mbox_tx_interrupt(struct omap_mbox *mbox)
 158 {
 159         omap_mbox_disable_irq(mbox, IRQ_TX);
 160         ack_mbox_irq(mbox, IRQ_TX);
 161         tasklet_schedule(&mbox->txq->tasklet);
 162 }
 163
 164 static void __mbox_rx_interrupt(struct omap_mbox *mbox)
 165 {
 166         struct omap_mbox_queue *mq = mbox->rxq;
 167         mbox_msg_t msg;
 168         int len;
 169
 170         while (!mbox_fifo_empty(mbox)) {
 171                 if (unlikely(kfifo_avail(&mq->fifo) < sizeof(msg))) {
 172                         omap_mbox_disable_irq(mbox, IRQ_RX);
 173                         rq_full = true;
 174                         goto nomem;
 175                 }
 176
 177                 msg = mbox_fifo_read(mbox);
 178
 179                 len = kfifo_in(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
 180                 WARN_ON(len != sizeof(msg));
 181
 182                 if (mbox->ops->type == OMAP_MBOX_TYPE1)
 183                         break;
 184         }
 185
 186         /* no more messages in the fifo. clear IRQ source. */
 187         ack_mbox_irq(mbox, IRQ_RX);
 188 nomem:
 189         queue_work(mboxd, &mbox->rxq->work);
 190 }
 191
 192 static irqreturn_t mbox_interrupt(int irq, void *p)
 193 {
 194         struct omap_mbox *mbox = p;
 195
 196         if (is_mbox_irq(mbox, IRQ_TX))
 197                 __mbox_tx_interrupt(mbox);
 198
 199         if (is_mbox_irq(mbox, IRQ_RX))
 200                 __mbox_rx_interrupt(mbox);
 201
 202         return IRQ_HANDLED;
 203 }
 204
 205 static struct omap_mbox_queue *mbox_queue_alloc(struct omap_mbox *mbox,
 206                                         void (*work) (struct work_struct *),
 207                                         void (*tasklet)(unsigned long))
 208 {
 209         struct omap_mbox_queue *mq;
 210
 211         mq = kzalloc(sizeof(struct omap_mbox_queue), GFP_KERNEL);
 212         if (!mq)
 213                 return NULL;
 214
 215         spin_lock_init(&mq->lock);
 216
 217         if (kfifo_alloc(&mq->fifo, mbox_kfifo_size, GFP_KERNEL))
 218                 goto error;
 219
 220         if (work)
 221                 INIT_WORK(&mq->work, work);
 222
 223         if (tasklet)
 224                 tasklet_init(&mq->tasklet, tasklet, (unsigned long)mbox);
 225         return mq;
 226 error:
 227         kfree(mq);
 228         return NULL;
 229 }
 230
 231 static void mbox_queue_free(struct omap_mbox_queue *q)
 232 {
 233         kfifo_free(&q->fifo);
 234         kfree(q);
 235 }
 236
 237 static int omap_mbox_startup(struct omap_mbox *mbox)
 238 {
 239         int ret = 0;
 240         struct omap_mbox_queue *mq;
 241
 242         if (mbox->ops->startup) {
 243                 mutex_lock(&mbox_configured_lock);
 244                 if (!mbox_configured)
 245                         ret = mbox->ops->startup(mbox);
 246
 247                 if (ret) {
 248                         mutex_unlock(&mbox_configured_lock);
 249                         return ret;
 250                 }
 251                 mbox_configured++;
 252                 mutex_unlock(&mbox_configured_lock);
 253         }
 254
 255         ret = request_irq(mbox->irq, mbox_interrupt, IRQF_SHARED,
 256                                 mbox->name, mbox);
 257         if (ret) {
 258                 printk(KERN_ERR
 259                         "failed to register mailbox interrupt:%d\n", ret);
 260                 goto fail_request_irq;
 261         }
 262
 263         mq = mbox_queue_alloc(mbox, NULL, mbox_tx_tasklet);
 264         if (!mq) {
 265                 ret = -ENOMEM;
 266                 goto fail_alloc_txq;
 267         }
 268         mbox->txq = mq;
 269
 270         mq = mbox_queue_alloc(mbox, mbox_rx_work, NULL);
 271         if (!mq) {
 272                 ret = -ENOMEM;
 273                 goto fail_alloc_rxq;
 274         }
 275         mbox->rxq = mq;
 276
 277         return 0;
 278
 279  fail_alloc_rxq:
 280         mbox_queue_free(mbox->txq);
 281  fail_alloc_txq:
 282         free_irq(mbox->irq, mbox);
 283  fail_request_irq:
 284         if (mbox->ops->shutdown)
 285                 mbox->ops->shutdown(mbox);
 286
 287         return ret;
 288 }
 289
 290 static void omap_mbox_fini(struct omap_mbox *mbox)
 291 {
 292         free_irq(mbox->irq, mbox);
 293         tasklet_kill(&mbox->txq->tasklet);
 294         flush_work(&mbox->rxq->work);
 295         mbox_queue_free(mbox->txq);
 296         mbox_queue_free(mbox->rxq);
 297
 298         if (mbox->ops->shutdown) {
 299                 mutex_lock(&mbox_configured_lock);
 300                 if (mbox_configured > 0)
 301                         mbox_configured--;
 302                 if (!mbox_configured)
 303                         mbox->ops->shutdown(mbox);
 304                 mutex_unlock(&mbox_configured_lock);
 305         }
 306 }
 307
 308 struct omap_mbox *omap_mbox_get(const char *name)
 309 {
 310         struct omap_mbox *mbox;
 311         int ret;
 312
 313         if (!mboxes)
 314                 return ERR_PTR(-EINVAL);
 315
 316         for (mbox = *mboxes; mbox; mbox++)
 317                 if (!strcmp(mbox->name, name))
 318                         break;
 319
 320         if (!mbox)
 321                 return ERR_PTR(-ENOENT);
 322
 323         ret = omap_mbox_startup(mbox);
 324         if (ret)
 325                 return ERR_PTR(-ENODEV);
 326
 327         return mbox;
 328 }
 329 EXPORT_SYMBOL(omap_mbox_get);
 330
 331 void omap_mbox_put(struct omap_mbox *mbox)
 332 {
 333         omap_mbox_fini(mbox);
 334 }
 335 EXPORT_SYMBOL(omap_mbox_put);
 336
 337 static struct class omap_mbox_class = { .name = "mbox", };
 338
 339 int omap_mbox_register(struct device *parent, struct omap_mbox **list)
 340 {
 341         int ret;
 342         int i;
 343
 344         mboxes = list;
 345         if (!mboxes)
 346                 return -EINVAL;
 347
 348         for (i = 0; mboxes[i]; i++) {
 349                 struct omap_mbox *mbox = mboxes[i];
 350                 mbox->dev = device_create(&omap_mbox_class,
 351                                 parent, 0, mbox, "%s", mbox->name);
 352                 if (IS_ERR(mbox->dev)) {
 353                         ret = PTR_ERR(mbox->dev);
 354                         goto err_out;
 355                 }
 356         }
 357         return 0;
 358
 359 err_out:
 360         while (i--)
 361                 device_unregister(mboxes[i]->dev);
 362         return ret;
 363 }
 364 EXPORT_SYMBOL(omap_mbox_register);
 365
 366 int omap_mbox_unregister(void)
 367 {
 368         int i;
 369
 370         if (!mboxes)
 371                 return -EINVAL;
 372
 373         for (i = 0; mboxes[i]; i++)
 374                 device_unregister(mboxes[i]->dev);
 375         mboxes = NULL;
 376         return 0;
 377 }
 378 EXPORT_SYMBOL(omap_mbox_unregister);
 379
 380 static int __init omap_mbox_init(void)
 381 {
 382         int err;
 383
 384         err = class_register(&omap_mbox_class);
 385         if (err)
 386                 return err;
 387
 388         mboxd = create_workqueue("mboxd");
 389         if (!mboxd)
 390                 return -ENOMEM;
 391
 392         /* kfifo size sanity check: alignment and minimal size */
 393         mbox_kfifo_size = ALIGN(mbox_kfifo_size, sizeof(mbox_msg_t));
 394         mbox_kfifo_size = max_t(unsigned int, mbox_kfifo_size, sizeof(mbox_msg_t));
 395
 396         return 0;
 397 }
 398 subsys_initcall(omap_mbox_init);
 399
 400 static void __exit omap_mbox_exit(void)
 401 {
 402         destroy_workqueue(mboxd);
 403         class_unregister(&omap_mbox_class);
 404 }
 405 module_exit(omap_mbox_exit);
 406
 407 MODULE_LICENSE("GPL v2");
 408 MODULE_DESCRIPTION("omap mailbox: interrupt driven messaging");
 409 MODULE_AUTHOR("Toshihiro Kobayashi");
 410 MODULE_AUTHOR("Hiroshi DOYU");