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Linux/arch/arm/plat-omap/mailbox.c

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  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 #include <linux/module.h>
 33 
 34 #include <plat/mailbox.h>
 35 
 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         schedule_work(&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_sync(&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, *mbox = NULL;
326         int i, ret;
327 
328         if (!mboxes)
329                 return ERR_PTR(-EINVAL);
330 
331         for (i = 0; (_mbox = mboxes[i]); i++) {
332                 if (!strcmp(_mbox->name, name)) {
333                         mbox = _mbox;
334                         break;
335                 }
336         }
337 
338         if (!mbox)
339                 return ERR_PTR(-ENOENT);
340 
341         ret = omap_mbox_startup(mbox);
342         if (ret)
343                 return ERR_PTR(-ENODEV);
344 
345         if (nb)
346                 blocking_notifier_chain_register(&mbox->notifier, nb);
347 
348         return mbox;
349 }
350 EXPORT_SYMBOL(omap_mbox_get);
351 
352 void omap_mbox_put(struct omap_mbox *mbox, struct notifier_block *nb)
353 {
354         blocking_notifier_chain_unregister(&mbox->notifier, nb);
355         omap_mbox_fini(mbox);
356 }
357 EXPORT_SYMBOL(omap_mbox_put);
358 
359 static struct class omap_mbox_class = { .name = "mbox", };
360 
361 int omap_mbox_register(struct device *parent, struct omap_mbox **list)
362 {
363         int ret;
364         int i;
365 
366         mboxes = list;
367         if (!mboxes)
368                 return -EINVAL;
369 
370         for (i = 0; mboxes[i]; i++) {
371                 struct omap_mbox *mbox = mboxes[i];
372                 mbox->dev = device_create(&omap_mbox_class,
373                                 parent, 0, mbox, "%s", mbox->name);
374                 if (IS_ERR(mbox->dev)) {
375                         ret = PTR_ERR(mbox->dev);
376                         goto err_out;
377                 }
378 
379                 BLOCKING_INIT_NOTIFIER_HEAD(&mbox->notifier);
380         }
381         return 0;
382 
383 err_out:
384         while (i--)
385                 device_unregister(mboxes[i]->dev);
386         return ret;
387 }
388 EXPORT_SYMBOL(omap_mbox_register);
389 
390 int omap_mbox_unregister(void)
391 {
392         int i;
393 
394         if (!mboxes)
395                 return -EINVAL;
396 
397         for (i = 0; mboxes[i]; i++)
398                 device_unregister(mboxes[i]->dev);
399         mboxes = NULL;
400         return 0;
401 }
402 EXPORT_SYMBOL(omap_mbox_unregister);
403 
404 static int __init omap_mbox_init(void)
405 {
406         int err;
407 
408         err = class_register(&omap_mbox_class);
409         if (err)
410                 return err;
411 
412         /* kfifo size sanity check: alignment and minimal size */
413         mbox_kfifo_size = ALIGN(mbox_kfifo_size, sizeof(mbox_msg_t));
414         mbox_kfifo_size = max_t(unsigned int, mbox_kfifo_size,
415                                                         sizeof(mbox_msg_t));
416 
417         return 0;
418 }
419 subsys_initcall(omap_mbox_init);
420 
421 static void __exit omap_mbox_exit(void)
422 {
423         class_unregister(&omap_mbox_class);
424 }
425 module_exit(omap_mbox_exit);
426 
427 MODULE_LICENSE("GPL v2");
428 MODULE_DESCRIPTION("omap mailbox: interrupt driven messaging");
429 MODULE_AUTHOR("Toshihiro Kobayashi");
430 MODULE_AUTHOR("Hiroshi DOYU");
431 

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