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 */
mbox_fifo_read(struct omap_mbox * mbox)46 static inline mbox_msg_t mbox_fifo_read(struct omap_mbox *mbox)
47 {
48 return mbox->ops->fifo_read(mbox);
49 }
mbox_fifo_write(struct omap_mbox * mbox,mbox_msg_t msg)50 static inline void mbox_fifo_write(struct omap_mbox *mbox, mbox_msg_t msg)
51 {
52 mbox->ops->fifo_write(mbox, msg);
53 }
mbox_fifo_empty(struct omap_mbox * mbox)54 static inline int mbox_fifo_empty(struct omap_mbox *mbox)
55 {
56 return mbox->ops->fifo_empty(mbox);
57 }
mbox_fifo_full(struct omap_mbox * mbox)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 */
ack_mbox_irq(struct omap_mbox * mbox,omap_mbox_irq_t irq)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 }
is_mbox_irq(struct omap_mbox * mbox,omap_mbox_irq_t irq)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 */
__mbox_poll_for_space(struct omap_mbox * mbox)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
omap_mbox_msg_send(struct omap_mbox * mbox,mbox_msg_t msg)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
mbox_tx_tasklet(unsigned long tx_data)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 */
mbox_rx_work(struct work_struct * work)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 */
__mbox_tx_interrupt(struct omap_mbox * mbox)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
__mbox_rx_interrupt(struct omap_mbox * mbox)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
mbox_interrupt(int irq,void * p)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
mbox_queue_alloc(struct omap_mbox * mbox,void (* work)(struct work_struct *),void (* tasklet)(unsigned long))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
mbox_queue_free(struct omap_mbox_queue * q)242 static void mbox_queue_free(struct omap_mbox_queue *q)
243 {
244 kfifo_free(&q->fifo);
245 kfree(q);
246 }
247
omap_mbox_startup(struct omap_mbox * mbox)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
omap_mbox_fini(struct omap_mbox * mbox)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
omap_mbox_get(const char * name,struct notifier_block * nb)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
omap_mbox_put(struct omap_mbox * mbox,struct notifier_block * nb)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
omap_mbox_register(struct device * parent,struct omap_mbox ** list)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
omap_mbox_unregister(void)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
omap_mbox_init(void)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
omap_mbox_exit(void)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