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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Mailbox: Common code for Mailbox controllers and users
4 *
5 * Copyright (C) 2013-2014 Linaro Ltd.
6 * Author: Jassi Brar <jassisinghbrar@gmail.com>
7 */
8
9#include <linux/interrupt.h>
10#include <linux/spinlock.h>
11#include <linux/mutex.h>
12#include <linux/delay.h>
13#include <linux/slab.h>
14#include <linux/err.h>
15#include <linux/module.h>
16#include <linux/device.h>
17#include <linux/bitops.h>
18#include <linux/mailbox_client.h>
19#include <linux/mailbox_controller.h>
20
21#include "mailbox.h"
22
23static LIST_HEAD(mbox_cons);
24static DEFINE_MUTEX(con_mutex);
25
26static int add_to_rbuf(struct mbox_chan *chan, void *mssg)
27{
28 int idx;
29 unsigned long flags;
30
31 spin_lock_irqsave(&chan->lock, flags);
32
33 /* See if there is any space left */
34 if (chan->msg_count == MBOX_TX_QUEUE_LEN) {
35 spin_unlock_irqrestore(&chan->lock, flags);
36 return -ENOBUFS;
37 }
38
39 idx = chan->msg_free;
40 chan->msg_data[idx] = mssg;
41 chan->msg_count++;
42
43 if (idx == MBOX_TX_QUEUE_LEN - 1)
44 chan->msg_free = 0;
45 else
46 chan->msg_free++;
47
48 spin_unlock_irqrestore(&chan->lock, flags);
49
50 return idx;
51}
52
53static void msg_submit(struct mbox_chan *chan)
54{
55 unsigned count, idx;
56 unsigned long flags;
57 void *data;
58 int err = -EBUSY;
59
60 spin_lock_irqsave(&chan->lock, flags);
61
62 if (!chan->msg_count || chan->active_req)
63 goto exit;
64
65 count = chan->msg_count;
66 idx = chan->msg_free;
67 if (idx >= count)
68 idx -= count;
69 else
70 idx += MBOX_TX_QUEUE_LEN - count;
71
72 data = chan->msg_data[idx];
73
74 if (chan->cl->tx_prepare)
75 chan->cl->tx_prepare(chan->cl, data);
76 /* Try to submit a message to the MBOX controller */
77 err = chan->mbox->ops->send_data(chan, data);
78 if (!err) {
79 chan->active_req = data;
80 chan->msg_count--;
81 }
82exit:
83 spin_unlock_irqrestore(&chan->lock, flags);
84
85 if (!err && (chan->txdone_method & TXDONE_BY_POLL)) {
86 /* kick start the timer immediately to avoid delays */
87 spin_lock_irqsave(&chan->mbox->poll_hrt_lock, flags);
88 hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL);
89 spin_unlock_irqrestore(&chan->mbox->poll_hrt_lock, flags);
90 }
91}
92
93static void tx_tick(struct mbox_chan *chan, int r)
94{
95 unsigned long flags;
96 void *mssg;
97
98 spin_lock_irqsave(&chan->lock, flags);
99 mssg = chan->active_req;
100 chan->active_req = NULL;
101 spin_unlock_irqrestore(&chan->lock, flags);
102
103 /* Submit next message */
104 msg_submit(chan);
105
106 if (!mssg)
107 return;
108
109 /* Notify the client */
110 if (chan->cl->tx_done)
111 chan->cl->tx_done(chan->cl, mssg, r);
112
113 if (r != -ETIME && chan->cl->tx_block)
114 complete(&chan->tx_complete);
115}
116
117static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer)
118{
119 struct mbox_controller *mbox =
120 container_of(hrtimer, struct mbox_controller, poll_hrt);
121 bool txdone, resched = false;
122 int i;
123 unsigned long flags;
124
125 for (i = 0; i < mbox->num_chans; i++) {
126 struct mbox_chan *chan = &mbox->chans[i];
127
128 if (chan->active_req && chan->cl) {
129 txdone = chan->mbox->ops->last_tx_done(chan);
130 if (txdone)
131 tx_tick(chan, 0);
132 else
133 resched = true;
134 }
135 }
136
137 if (resched) {
138 spin_lock_irqsave(&mbox->poll_hrt_lock, flags);
139 if (!hrtimer_is_queued(hrtimer))
140 hrtimer_forward_now(hrtimer, ms_to_ktime(mbox->txpoll_period));
141 spin_unlock_irqrestore(&mbox->poll_hrt_lock, flags);
142
143 return HRTIMER_RESTART;
144 }
145 return HRTIMER_NORESTART;
146}
147
148/**
149 * mbox_chan_received_data - A way for controller driver to push data
150 * received from remote to the upper layer.
151 * @chan: Pointer to the mailbox channel on which RX happened.
152 * @mssg: Client specific message typecasted as void *
153 *
154 * After startup and before shutdown any data received on the chan
155 * is passed on to the API via atomic mbox_chan_received_data().
156 * The controller should ACK the RX only after this call returns.
157 */
158void mbox_chan_received_data(struct mbox_chan *chan, void *mssg)
159{
160 /* No buffering the received data */
161 if (chan->cl->rx_callback)
162 chan->cl->rx_callback(chan->cl, mssg);
163}
164EXPORT_SYMBOL_GPL(mbox_chan_received_data);
165
166/**
167 * mbox_chan_txdone - A way for controller driver to notify the
168 * framework that the last TX has completed.
169 * @chan: Pointer to the mailbox chan on which TX happened.
170 * @r: Status of last TX - OK or ERROR
171 *
172 * The controller that has IRQ for TX ACK calls this atomic API
173 * to tick the TX state machine. It works only if txdone_irq
174 * is set by the controller.
175 */
176void mbox_chan_txdone(struct mbox_chan *chan, int r)
177{
178 if (unlikely(!(chan->txdone_method & TXDONE_BY_IRQ))) {
179 dev_err(chan->mbox->dev,
180 "Controller can't run the TX ticker\n");
181 return;
182 }
183
184 tx_tick(chan, r);
185}
186EXPORT_SYMBOL_GPL(mbox_chan_txdone);
187
188/**
189 * mbox_client_txdone - The way for a client to run the TX state machine.
190 * @chan: Mailbox channel assigned to this client.
191 * @r: Success status of last transmission.
192 *
193 * The client/protocol had received some 'ACK' packet and it notifies
194 * the API that the last packet was sent successfully. This only works
195 * if the controller can't sense TX-Done.
196 */
197void mbox_client_txdone(struct mbox_chan *chan, int r)
198{
199 if (unlikely(!(chan->txdone_method & TXDONE_BY_ACK))) {
200 dev_err(chan->mbox->dev, "Client can't run the TX ticker\n");
201 return;
202 }
203
204 tx_tick(chan, r);
205}
206EXPORT_SYMBOL_GPL(mbox_client_txdone);
207
208/**
209 * mbox_client_peek_data - A way for client driver to pull data
210 * received from remote by the controller.
211 * @chan: Mailbox channel assigned to this client.
212 *
213 * A poke to controller driver for any received data.
214 * The data is actually passed onto client via the
215 * mbox_chan_received_data()
216 * The call can be made from atomic context, so the controller's
217 * implementation of peek_data() must not sleep.
218 *
219 * Return: True, if controller has, and is going to push after this,
220 * some data.
221 * False, if controller doesn't have any data to be read.
222 */
223bool mbox_client_peek_data(struct mbox_chan *chan)
224{
225 if (chan->mbox->ops->peek_data)
226 return chan->mbox->ops->peek_data(chan);
227
228 return false;
229}
230EXPORT_SYMBOL_GPL(mbox_client_peek_data);
231
232/**
233 * mbox_send_message - For client to submit a message to be
234 * sent to the remote.
235 * @chan: Mailbox channel assigned to this client.
236 * @mssg: Client specific message typecasted.
237 *
238 * For client to submit data to the controller destined for a remote
239 * processor. If the client had set 'tx_block', the call will return
240 * either when the remote receives the data or when 'tx_tout' millisecs
241 * run out.
242 * In non-blocking mode, the requests are buffered by the API and a
243 * non-negative token is returned for each queued request. If the request
244 * is not queued, a negative token is returned. Upon failure or successful
245 * TX, the API calls 'tx_done' from atomic context, from which the client
246 * could submit yet another request.
247 * The pointer to message should be preserved until it is sent
248 * over the chan, i.e, tx_done() is made.
249 * This function could be called from atomic context as it simply
250 * queues the data and returns a token against the request.
251 *
252 * Return: Non-negative integer for successful submission (non-blocking mode)
253 * or transmission over chan (blocking mode).
254 * Negative value denotes failure.
255 */
256int mbox_send_message(struct mbox_chan *chan, void *mssg)
257{
258 int t;
259
260 if (!chan || !chan->cl)
261 return -EINVAL;
262
263 t = add_to_rbuf(chan, mssg);
264 if (t < 0) {
265 dev_err(chan->mbox->dev, "Try increasing MBOX_TX_QUEUE_LEN\n");
266 return t;
267 }
268
269 msg_submit(chan);
270
271 if (chan->cl->tx_block) {
272 unsigned long wait;
273 int ret;
274
275 if (!chan->cl->tx_tout) /* wait forever */
276 wait = msecs_to_jiffies(3600000);
277 else
278 wait = msecs_to_jiffies(chan->cl->tx_tout);
279
280 ret = wait_for_completion_timeout(&chan->tx_complete, wait);
281 if (ret == 0) {
282 t = -ETIME;
283 tx_tick(chan, t);
284 }
285 }
286
287 return t;
288}
289EXPORT_SYMBOL_GPL(mbox_send_message);
290
291/**
292 * mbox_flush - flush a mailbox channel
293 * @chan: mailbox channel to flush
294 * @timeout: time, in milliseconds, to allow the flush operation to succeed
295 *
296 * Mailbox controllers that need to work in atomic context can implement the
297 * ->flush() callback to busy loop until a transmission has been completed.
298 * The implementation must call mbox_chan_txdone() upon success. Clients can
299 * call the mbox_flush() function at any time after mbox_send_message() to
300 * flush the transmission. After the function returns success, the mailbox
301 * transmission is guaranteed to have completed.
302 *
303 * Returns: 0 on success or a negative error code on failure.
304 */
305int mbox_flush(struct mbox_chan *chan, unsigned long timeout)
306{
307 int ret;
308
309 if (!chan->mbox->ops->flush)
310 return -ENOTSUPP;
311
312 ret = chan->mbox->ops->flush(chan, timeout);
313 if (ret < 0)
314 tx_tick(chan, ret);
315
316 return ret;
317}
318EXPORT_SYMBOL_GPL(mbox_flush);
319
320/**
321 * mbox_request_channel - Request a mailbox channel.
322 * @cl: Identity of the client requesting the channel.
323 * @index: Index of mailbox specifier in 'mboxes' property.
324 *
325 * The Client specifies its requirements and capabilities while asking for
326 * a mailbox channel. It can't be called from atomic context.
327 * The channel is exclusively allocated and can't be used by another
328 * client before the owner calls mbox_free_channel.
329 * After assignment, any packet received on this channel will be
330 * handed over to the client via the 'rx_callback'.
331 * The framework holds reference to the client, so the mbox_client
332 * structure shouldn't be modified until the mbox_free_channel returns.
333 *
334 * Return: Pointer to the channel assigned to the client if successful.
335 * ERR_PTR for request failure.
336 */
337struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
338{
339 struct device *dev = cl->dev;
340 struct mbox_controller *mbox;
341 struct of_phandle_args spec;
342 struct mbox_chan *chan;
343 unsigned long flags;
344 int ret;
345
346 if (!dev || !dev->of_node) {
347 pr_debug("%s: No owner device node\n", __func__);
348 return ERR_PTR(-ENODEV);
349 }
350
351 mutex_lock(&con_mutex);
352
353 if (of_parse_phandle_with_args(dev->of_node, "mboxes",
354 "#mbox-cells", index, &spec)) {
355 dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__);
356 mutex_unlock(&con_mutex);
357 return ERR_PTR(-ENODEV);
358 }
359
360 chan = ERR_PTR(-EPROBE_DEFER);
361 list_for_each_entry(mbox, &mbox_cons, node)
362 if (mbox->dev->of_node == spec.np) {
363 chan = mbox->of_xlate(mbox, &spec);
364 if (!IS_ERR(chan))
365 break;
366 }
367
368 of_node_put(spec.np);
369
370 if (IS_ERR(chan)) {
371 mutex_unlock(&con_mutex);
372 return chan;
373 }
374
375 if (chan->cl || !try_module_get(mbox->dev->driver->owner)) {
376 dev_dbg(dev, "%s: mailbox not free\n", __func__);
377 mutex_unlock(&con_mutex);
378 return ERR_PTR(-EBUSY);
379 }
380
381 spin_lock_irqsave(&chan->lock, flags);
382 chan->msg_free = 0;
383 chan->msg_count = 0;
384 chan->active_req = NULL;
385 chan->cl = cl;
386 init_completion(&chan->tx_complete);
387
388 if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
389 chan->txdone_method = TXDONE_BY_ACK;
390
391 spin_unlock_irqrestore(&chan->lock, flags);
392
393 if (chan->mbox->ops->startup) {
394 ret = chan->mbox->ops->startup(chan);
395
396 if (ret) {
397 dev_err(dev, "Unable to startup the chan (%d)\n", ret);
398 mbox_free_channel(chan);
399 chan = ERR_PTR(ret);
400 }
401 }
402
403 mutex_unlock(&con_mutex);
404 return chan;
405}
406EXPORT_SYMBOL_GPL(mbox_request_channel);
407
408struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl,
409 const char *name)
410{
411 struct device_node *np = cl->dev->of_node;
412 struct property *prop;
413 const char *mbox_name;
414 int index = 0;
415
416 if (!np) {
417 dev_err(cl->dev, "%s() currently only supports DT\n", __func__);
418 return ERR_PTR(-EINVAL);
419 }
420
421 if (!of_get_property(np, "mbox-names", NULL)) {
422 dev_err(cl->dev,
423 "%s() requires an \"mbox-names\" property\n", __func__);
424 return ERR_PTR(-EINVAL);
425 }
426
427 of_property_for_each_string(np, "mbox-names", prop, mbox_name) {
428 if (!strncmp(name, mbox_name, strlen(name)))
429 return mbox_request_channel(cl, index);
430 index++;
431 }
432
433 dev_err(cl->dev, "%s() could not locate channel named \"%s\"\n",
434 __func__, name);
435 return ERR_PTR(-EINVAL);
436}
437EXPORT_SYMBOL_GPL(mbox_request_channel_byname);
438
439/**
440 * mbox_free_channel - The client relinquishes control of a mailbox
441 * channel by this call.
442 * @chan: The mailbox channel to be freed.
443 */
444void mbox_free_channel(struct mbox_chan *chan)
445{
446 unsigned long flags;
447
448 if (!chan || !chan->cl)
449 return;
450
451 if (chan->mbox->ops->shutdown)
452 chan->mbox->ops->shutdown(chan);
453
454 /* The queued TX requests are simply aborted, no callbacks are made */
455 spin_lock_irqsave(&chan->lock, flags);
456 chan->cl = NULL;
457 chan->active_req = NULL;
458 if (chan->txdone_method == TXDONE_BY_ACK)
459 chan->txdone_method = TXDONE_BY_POLL;
460
461 module_put(chan->mbox->dev->driver->owner);
462 spin_unlock_irqrestore(&chan->lock, flags);
463}
464EXPORT_SYMBOL_GPL(mbox_free_channel);
465
466static struct mbox_chan *
467of_mbox_index_xlate(struct mbox_controller *mbox,
468 const struct of_phandle_args *sp)
469{
470 int ind = sp->args[0];
471
472 if (ind >= mbox->num_chans)
473 return ERR_PTR(-EINVAL);
474
475 return &mbox->chans[ind];
476}
477
478/**
479 * mbox_controller_register - Register the mailbox controller
480 * @mbox: Pointer to the mailbox controller.
481 *
482 * The controller driver registers its communication channels
483 */
484int mbox_controller_register(struct mbox_controller *mbox)
485{
486 int i, txdone;
487
488 /* Sanity check */
489 if (!mbox || !mbox->dev || !mbox->ops || !mbox->num_chans)
490 return -EINVAL;
491
492 if (mbox->txdone_irq)
493 txdone = TXDONE_BY_IRQ;
494 else if (mbox->txdone_poll)
495 txdone = TXDONE_BY_POLL;
496 else /* It has to be ACK then */
497 txdone = TXDONE_BY_ACK;
498
499 if (txdone == TXDONE_BY_POLL) {
500
501 if (!mbox->ops->last_tx_done) {
502 dev_err(mbox->dev, "last_tx_done method is absent\n");
503 return -EINVAL;
504 }
505
506 hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC,
507 HRTIMER_MODE_REL);
508 mbox->poll_hrt.function = txdone_hrtimer;
509 spin_lock_init(&mbox->poll_hrt_lock);
510 }
511
512 for (i = 0; i < mbox->num_chans; i++) {
513 struct mbox_chan *chan = &mbox->chans[i];
514
515 chan->cl = NULL;
516 chan->mbox = mbox;
517 chan->txdone_method = txdone;
518 spin_lock_init(&chan->lock);
519 }
520
521 if (!mbox->of_xlate)
522 mbox->of_xlate = of_mbox_index_xlate;
523
524 mutex_lock(&con_mutex);
525 list_add_tail(&mbox->node, &mbox_cons);
526 mutex_unlock(&con_mutex);
527
528 return 0;
529}
530EXPORT_SYMBOL_GPL(mbox_controller_register);
531
532/**
533 * mbox_controller_unregister - Unregister the mailbox controller
534 * @mbox: Pointer to the mailbox controller.
535 */
536void mbox_controller_unregister(struct mbox_controller *mbox)
537{
538 int i;
539
540 if (!mbox)
541 return;
542
543 mutex_lock(&con_mutex);
544
545 list_del(&mbox->node);
546
547 for (i = 0; i < mbox->num_chans; i++)
548 mbox_free_channel(&mbox->chans[i]);
549
550 if (mbox->txdone_poll)
551 hrtimer_cancel(&mbox->poll_hrt);
552
553 mutex_unlock(&con_mutex);
554}
555EXPORT_SYMBOL_GPL(mbox_controller_unregister);
556
557static void __devm_mbox_controller_unregister(struct device *dev, void *res)
558{
559 struct mbox_controller **mbox = res;
560
561 mbox_controller_unregister(*mbox);
562}
563
564static int devm_mbox_controller_match(struct device *dev, void *res, void *data)
565{
566 struct mbox_controller **mbox = res;
567
568 if (WARN_ON(!mbox || !*mbox))
569 return 0;
570
571 return *mbox == data;
572}
573
574/**
575 * devm_mbox_controller_register() - managed mbox_controller_register()
576 * @dev: device owning the mailbox controller being registered
577 * @mbox: mailbox controller being registered
578 *
579 * This function adds a device-managed resource that will make sure that the
580 * mailbox controller, which is registered using mbox_controller_register()
581 * as part of this function, will be unregistered along with the rest of
582 * device-managed resources upon driver probe failure or driver removal.
583 *
584 * Returns 0 on success or a negative error code on failure.
585 */
586int devm_mbox_controller_register(struct device *dev,
587 struct mbox_controller *mbox)
588{
589 struct mbox_controller **ptr;
590 int err;
591
592 ptr = devres_alloc(__devm_mbox_controller_unregister, sizeof(*ptr),
593 GFP_KERNEL);
594 if (!ptr)
595 return -ENOMEM;
596
597 err = mbox_controller_register(mbox);
598 if (err < 0) {
599 devres_free(ptr);
600 return err;
601 }
602
603 devres_add(dev, ptr);
604 *ptr = mbox;
605
606 return 0;
607}
608EXPORT_SYMBOL_GPL(devm_mbox_controller_register);
609
610/**
611 * devm_mbox_controller_unregister() - managed mbox_controller_unregister()
612 * @dev: device owning the mailbox controller being unregistered
613 * @mbox: mailbox controller being unregistered
614 *
615 * This function unregisters the mailbox controller and removes the device-
616 * managed resource that was set up to automatically unregister the mailbox
617 * controller on driver probe failure or driver removal. It's typically not
618 * necessary to call this function.
619 */
620void devm_mbox_controller_unregister(struct device *dev, struct mbox_controller *mbox)
621{
622 WARN_ON(devres_release(dev, __devm_mbox_controller_unregister,
623 devm_mbox_controller_match, mbox));
624}
625EXPORT_SYMBOL_GPL(devm_mbox_controller_unregister);
1/*
2 * Mailbox: Common code for Mailbox controllers and users
3 *
4 * Copyright (C) 2013-2014 Linaro Ltd.
5 * Author: Jassi Brar <jassisinghbrar@gmail.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/interrupt.h>
13#include <linux/spinlock.h>
14#include <linux/mutex.h>
15#include <linux/delay.h>
16#include <linux/slab.h>
17#include <linux/err.h>
18#include <linux/module.h>
19#include <linux/device.h>
20#include <linux/bitops.h>
21#include <linux/mailbox_client.h>
22#include <linux/mailbox_controller.h>
23
24#include "mailbox.h"
25
26static LIST_HEAD(mbox_cons);
27static DEFINE_MUTEX(con_mutex);
28
29static int add_to_rbuf(struct mbox_chan *chan, void *mssg)
30{
31 int idx;
32 unsigned long flags;
33
34 spin_lock_irqsave(&chan->lock, flags);
35
36 /* See if there is any space left */
37 if (chan->msg_count == MBOX_TX_QUEUE_LEN) {
38 spin_unlock_irqrestore(&chan->lock, flags);
39 return -ENOBUFS;
40 }
41
42 idx = chan->msg_free;
43 chan->msg_data[idx] = mssg;
44 chan->msg_count++;
45
46 if (idx == MBOX_TX_QUEUE_LEN - 1)
47 chan->msg_free = 0;
48 else
49 chan->msg_free++;
50
51 spin_unlock_irqrestore(&chan->lock, flags);
52
53 return idx;
54}
55
56static void msg_submit(struct mbox_chan *chan)
57{
58 unsigned count, idx;
59 unsigned long flags;
60 void *data;
61 int err = -EBUSY;
62
63 spin_lock_irqsave(&chan->lock, flags);
64
65 if (!chan->msg_count || chan->active_req)
66 goto exit;
67
68 count = chan->msg_count;
69 idx = chan->msg_free;
70 if (idx >= count)
71 idx -= count;
72 else
73 idx += MBOX_TX_QUEUE_LEN - count;
74
75 data = chan->msg_data[idx];
76
77 if (chan->cl->tx_prepare)
78 chan->cl->tx_prepare(chan->cl, data);
79 /* Try to submit a message to the MBOX controller */
80 err = chan->mbox->ops->send_data(chan, data);
81 if (!err) {
82 chan->active_req = data;
83 chan->msg_count--;
84 }
85exit:
86 spin_unlock_irqrestore(&chan->lock, flags);
87
88 if (!err && (chan->txdone_method & TXDONE_BY_POLL))
89 /* kick start the timer immediately to avoid delays */
90 hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL);
91}
92
93static void tx_tick(struct mbox_chan *chan, int r)
94{
95 unsigned long flags;
96 void *mssg;
97
98 spin_lock_irqsave(&chan->lock, flags);
99 mssg = chan->active_req;
100 chan->active_req = NULL;
101 spin_unlock_irqrestore(&chan->lock, flags);
102
103 /* Submit next message */
104 msg_submit(chan);
105
106 if (!mssg)
107 return;
108
109 /* Notify the client */
110 if (chan->cl->tx_done)
111 chan->cl->tx_done(chan->cl, mssg, r);
112
113 if (r != -ETIME && chan->cl->tx_block)
114 complete(&chan->tx_complete);
115}
116
117static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer)
118{
119 struct mbox_controller *mbox =
120 container_of(hrtimer, struct mbox_controller, poll_hrt);
121 bool txdone, resched = false;
122 int i;
123
124 for (i = 0; i < mbox->num_chans; i++) {
125 struct mbox_chan *chan = &mbox->chans[i];
126
127 if (chan->active_req && chan->cl) {
128 txdone = chan->mbox->ops->last_tx_done(chan);
129 if (txdone)
130 tx_tick(chan, 0);
131 else
132 resched = true;
133 }
134 }
135
136 if (resched) {
137 hrtimer_forward_now(hrtimer, ms_to_ktime(mbox->txpoll_period));
138 return HRTIMER_RESTART;
139 }
140 return HRTIMER_NORESTART;
141}
142
143/**
144 * mbox_chan_received_data - A way for controller driver to push data
145 * received from remote to the upper layer.
146 * @chan: Pointer to the mailbox channel on which RX happened.
147 * @mssg: Client specific message typecasted as void *
148 *
149 * After startup and before shutdown any data received on the chan
150 * is passed on to the API via atomic mbox_chan_received_data().
151 * The controller should ACK the RX only after this call returns.
152 */
153void mbox_chan_received_data(struct mbox_chan *chan, void *mssg)
154{
155 /* No buffering the received data */
156 if (chan->cl->rx_callback)
157 chan->cl->rx_callback(chan->cl, mssg);
158}
159EXPORT_SYMBOL_GPL(mbox_chan_received_data);
160
161/**
162 * mbox_chan_txdone - A way for controller driver to notify the
163 * framework that the last TX has completed.
164 * @chan: Pointer to the mailbox chan on which TX happened.
165 * @r: Status of last TX - OK or ERROR
166 *
167 * The controller that has IRQ for TX ACK calls this atomic API
168 * to tick the TX state machine. It works only if txdone_irq
169 * is set by the controller.
170 */
171void mbox_chan_txdone(struct mbox_chan *chan, int r)
172{
173 if (unlikely(!(chan->txdone_method & TXDONE_BY_IRQ))) {
174 dev_err(chan->mbox->dev,
175 "Controller can't run the TX ticker\n");
176 return;
177 }
178
179 tx_tick(chan, r);
180}
181EXPORT_SYMBOL_GPL(mbox_chan_txdone);
182
183/**
184 * mbox_client_txdone - The way for a client to run the TX state machine.
185 * @chan: Mailbox channel assigned to this client.
186 * @r: Success status of last transmission.
187 *
188 * The client/protocol had received some 'ACK' packet and it notifies
189 * the API that the last packet was sent successfully. This only works
190 * if the controller can't sense TX-Done.
191 */
192void mbox_client_txdone(struct mbox_chan *chan, int r)
193{
194 if (unlikely(!(chan->txdone_method & TXDONE_BY_ACK))) {
195 dev_err(chan->mbox->dev, "Client can't run the TX ticker\n");
196 return;
197 }
198
199 tx_tick(chan, r);
200}
201EXPORT_SYMBOL_GPL(mbox_client_txdone);
202
203/**
204 * mbox_client_peek_data - A way for client driver to pull data
205 * received from remote by the controller.
206 * @chan: Mailbox channel assigned to this client.
207 *
208 * A poke to controller driver for any received data.
209 * The data is actually passed onto client via the
210 * mbox_chan_received_data()
211 * The call can be made from atomic context, so the controller's
212 * implementation of peek_data() must not sleep.
213 *
214 * Return: True, if controller has, and is going to push after this,
215 * some data.
216 * False, if controller doesn't have any data to be read.
217 */
218bool mbox_client_peek_data(struct mbox_chan *chan)
219{
220 if (chan->mbox->ops->peek_data)
221 return chan->mbox->ops->peek_data(chan);
222
223 return false;
224}
225EXPORT_SYMBOL_GPL(mbox_client_peek_data);
226
227/**
228 * mbox_send_message - For client to submit a message to be
229 * sent to the remote.
230 * @chan: Mailbox channel assigned to this client.
231 * @mssg: Client specific message typecasted.
232 *
233 * For client to submit data to the controller destined for a remote
234 * processor. If the client had set 'tx_block', the call will return
235 * either when the remote receives the data or when 'tx_tout' millisecs
236 * run out.
237 * In non-blocking mode, the requests are buffered by the API and a
238 * non-negative token is returned for each queued request. If the request
239 * is not queued, a negative token is returned. Upon failure or successful
240 * TX, the API calls 'tx_done' from atomic context, from which the client
241 * could submit yet another request.
242 * The pointer to message should be preserved until it is sent
243 * over the chan, i.e, tx_done() is made.
244 * This function could be called from atomic context as it simply
245 * queues the data and returns a token against the request.
246 *
247 * Return: Non-negative integer for successful submission (non-blocking mode)
248 * or transmission over chan (blocking mode).
249 * Negative value denotes failure.
250 */
251int mbox_send_message(struct mbox_chan *chan, void *mssg)
252{
253 int t;
254
255 if (!chan || !chan->cl)
256 return -EINVAL;
257
258 t = add_to_rbuf(chan, mssg);
259 if (t < 0) {
260 dev_err(chan->mbox->dev, "Try increasing MBOX_TX_QUEUE_LEN\n");
261 return t;
262 }
263
264 msg_submit(chan);
265
266 if (chan->cl->tx_block) {
267 unsigned long wait;
268 int ret;
269
270 if (!chan->cl->tx_tout) /* wait forever */
271 wait = msecs_to_jiffies(3600000);
272 else
273 wait = msecs_to_jiffies(chan->cl->tx_tout);
274
275 ret = wait_for_completion_timeout(&chan->tx_complete, wait);
276 if (ret == 0) {
277 t = -ETIME;
278 tx_tick(chan, t);
279 }
280 }
281
282 return t;
283}
284EXPORT_SYMBOL_GPL(mbox_send_message);
285
286/**
287 * mbox_request_channel - Request a mailbox channel.
288 * @cl: Identity of the client requesting the channel.
289 * @index: Index of mailbox specifier in 'mboxes' property.
290 *
291 * The Client specifies its requirements and capabilities while asking for
292 * a mailbox channel. It can't be called from atomic context.
293 * The channel is exclusively allocated and can't be used by another
294 * client before the owner calls mbox_free_channel.
295 * After assignment, any packet received on this channel will be
296 * handed over to the client via the 'rx_callback'.
297 * The framework holds reference to the client, so the mbox_client
298 * structure shouldn't be modified until the mbox_free_channel returns.
299 *
300 * Return: Pointer to the channel assigned to the client if successful.
301 * ERR_PTR for request failure.
302 */
303struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
304{
305 struct device *dev = cl->dev;
306 struct mbox_controller *mbox;
307 struct of_phandle_args spec;
308 struct mbox_chan *chan;
309 unsigned long flags;
310 int ret;
311
312 if (!dev || !dev->of_node) {
313 pr_debug("%s: No owner device node\n", __func__);
314 return ERR_PTR(-ENODEV);
315 }
316
317 mutex_lock(&con_mutex);
318
319 if (of_parse_phandle_with_args(dev->of_node, "mboxes",
320 "#mbox-cells", index, &spec)) {
321 dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__);
322 mutex_unlock(&con_mutex);
323 return ERR_PTR(-ENODEV);
324 }
325
326 chan = ERR_PTR(-EPROBE_DEFER);
327 list_for_each_entry(mbox, &mbox_cons, node)
328 if (mbox->dev->of_node == spec.np) {
329 chan = mbox->of_xlate(mbox, &spec);
330 break;
331 }
332
333 of_node_put(spec.np);
334
335 if (IS_ERR(chan)) {
336 mutex_unlock(&con_mutex);
337 return chan;
338 }
339
340 if (chan->cl || !try_module_get(mbox->dev->driver->owner)) {
341 dev_dbg(dev, "%s: mailbox not free\n", __func__);
342 mutex_unlock(&con_mutex);
343 return ERR_PTR(-EBUSY);
344 }
345
346 spin_lock_irqsave(&chan->lock, flags);
347 chan->msg_free = 0;
348 chan->msg_count = 0;
349 chan->active_req = NULL;
350 chan->cl = cl;
351 init_completion(&chan->tx_complete);
352
353 if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
354 chan->txdone_method = TXDONE_BY_ACK;
355
356 spin_unlock_irqrestore(&chan->lock, flags);
357
358 if (chan->mbox->ops->startup) {
359 ret = chan->mbox->ops->startup(chan);
360
361 if (ret) {
362 dev_err(dev, "Unable to startup the chan (%d)\n", ret);
363 mbox_free_channel(chan);
364 chan = ERR_PTR(ret);
365 }
366 }
367
368 mutex_unlock(&con_mutex);
369 return chan;
370}
371EXPORT_SYMBOL_GPL(mbox_request_channel);
372
373struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl,
374 const char *name)
375{
376 struct device_node *np = cl->dev->of_node;
377 struct property *prop;
378 const char *mbox_name;
379 int index = 0;
380
381 if (!np) {
382 dev_err(cl->dev, "%s() currently only supports DT\n", __func__);
383 return ERR_PTR(-EINVAL);
384 }
385
386 if (!of_get_property(np, "mbox-names", NULL)) {
387 dev_err(cl->dev,
388 "%s() requires an \"mbox-names\" property\n", __func__);
389 return ERR_PTR(-EINVAL);
390 }
391
392 of_property_for_each_string(np, "mbox-names", prop, mbox_name) {
393 if (!strncmp(name, mbox_name, strlen(name)))
394 break;
395 index++;
396 }
397
398 return mbox_request_channel(cl, index);
399}
400EXPORT_SYMBOL_GPL(mbox_request_channel_byname);
401
402/**
403 * mbox_free_channel - The client relinquishes control of a mailbox
404 * channel by this call.
405 * @chan: The mailbox channel to be freed.
406 */
407void mbox_free_channel(struct mbox_chan *chan)
408{
409 unsigned long flags;
410
411 if (!chan || !chan->cl)
412 return;
413
414 if (chan->mbox->ops->shutdown)
415 chan->mbox->ops->shutdown(chan);
416
417 /* The queued TX requests are simply aborted, no callbacks are made */
418 spin_lock_irqsave(&chan->lock, flags);
419 chan->cl = NULL;
420 chan->active_req = NULL;
421 if (chan->txdone_method == TXDONE_BY_ACK)
422 chan->txdone_method = TXDONE_BY_POLL;
423
424 module_put(chan->mbox->dev->driver->owner);
425 spin_unlock_irqrestore(&chan->lock, flags);
426}
427EXPORT_SYMBOL_GPL(mbox_free_channel);
428
429static struct mbox_chan *
430of_mbox_index_xlate(struct mbox_controller *mbox,
431 const struct of_phandle_args *sp)
432{
433 int ind = sp->args[0];
434
435 if (ind >= mbox->num_chans)
436 return ERR_PTR(-EINVAL);
437
438 return &mbox->chans[ind];
439}
440
441/**
442 * mbox_controller_register - Register the mailbox controller
443 * @mbox: Pointer to the mailbox controller.
444 *
445 * The controller driver registers its communication channels
446 */
447int mbox_controller_register(struct mbox_controller *mbox)
448{
449 int i, txdone;
450
451 /* Sanity check */
452 if (!mbox || !mbox->dev || !mbox->ops || !mbox->num_chans)
453 return -EINVAL;
454
455 if (mbox->txdone_irq)
456 txdone = TXDONE_BY_IRQ;
457 else if (mbox->txdone_poll)
458 txdone = TXDONE_BY_POLL;
459 else /* It has to be ACK then */
460 txdone = TXDONE_BY_ACK;
461
462 if (txdone == TXDONE_BY_POLL) {
463
464 if (!mbox->ops->last_tx_done) {
465 dev_err(mbox->dev, "last_tx_done method is absent\n");
466 return -EINVAL;
467 }
468
469 hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC,
470 HRTIMER_MODE_REL);
471 mbox->poll_hrt.function = txdone_hrtimer;
472 }
473
474 for (i = 0; i < mbox->num_chans; i++) {
475 struct mbox_chan *chan = &mbox->chans[i];
476
477 chan->cl = NULL;
478 chan->mbox = mbox;
479 chan->txdone_method = txdone;
480 spin_lock_init(&chan->lock);
481 }
482
483 if (!mbox->of_xlate)
484 mbox->of_xlate = of_mbox_index_xlate;
485
486 mutex_lock(&con_mutex);
487 list_add_tail(&mbox->node, &mbox_cons);
488 mutex_unlock(&con_mutex);
489
490 return 0;
491}
492EXPORT_SYMBOL_GPL(mbox_controller_register);
493
494/**
495 * mbox_controller_unregister - Unregister the mailbox controller
496 * @mbox: Pointer to the mailbox controller.
497 */
498void mbox_controller_unregister(struct mbox_controller *mbox)
499{
500 int i;
501
502 if (!mbox)
503 return;
504
505 mutex_lock(&con_mutex);
506
507 list_del(&mbox->node);
508
509 for (i = 0; i < mbox->num_chans; i++)
510 mbox_free_channel(&mbox->chans[i]);
511
512 if (mbox->txdone_poll)
513 hrtimer_cancel(&mbox->poll_hrt);
514
515 mutex_unlock(&con_mutex);
516}
517EXPORT_SYMBOL_GPL(mbox_controller_unregister);