Loading...
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#include <linux/of.h>
21
22#include "mailbox.h"
23
24static LIST_HEAD(mbox_cons);
25static DEFINE_MUTEX(con_mutex);
26
27static int add_to_rbuf(struct mbox_chan *chan, void *mssg)
28{
29 int idx;
30 unsigned long flags;
31
32 spin_lock_irqsave(&chan->lock, flags);
33
34 /* See if there is any space left */
35 if (chan->msg_count == MBOX_TX_QUEUE_LEN) {
36 spin_unlock_irqrestore(&chan->lock, flags);
37 return -ENOBUFS;
38 }
39
40 idx = chan->msg_free;
41 chan->msg_data[idx] = mssg;
42 chan->msg_count++;
43
44 if (idx == MBOX_TX_QUEUE_LEN - 1)
45 chan->msg_free = 0;
46 else
47 chan->msg_free++;
48
49 spin_unlock_irqrestore(&chan->lock, flags);
50
51 return idx;
52}
53
54static void msg_submit(struct mbox_chan *chan)
55{
56 unsigned count, idx;
57 unsigned long flags;
58 void *data;
59 int err = -EBUSY;
60
61 spin_lock_irqsave(&chan->lock, flags);
62
63 if (!chan->msg_count || chan->active_req)
64 goto exit;
65
66 count = chan->msg_count;
67 idx = chan->msg_free;
68 if (idx >= count)
69 idx -= count;
70 else
71 idx += MBOX_TX_QUEUE_LEN - count;
72
73 data = chan->msg_data[idx];
74
75 if (chan->cl->tx_prepare)
76 chan->cl->tx_prepare(chan->cl, data);
77 /* Try to submit a message to the MBOX controller */
78 err = chan->mbox->ops->send_data(chan, data);
79 if (!err) {
80 chan->active_req = data;
81 chan->msg_count--;
82 }
83exit:
84 spin_unlock_irqrestore(&chan->lock, flags);
85
86 if (!err && (chan->txdone_method & TXDONE_BY_POLL)) {
87 /* kick start the timer immediately to avoid delays */
88 spin_lock_irqsave(&chan->mbox->poll_hrt_lock, flags);
89 hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL);
90 spin_unlock_irqrestore(&chan->mbox->poll_hrt_lock, flags);
91 }
92}
93
94static void tx_tick(struct mbox_chan *chan, int r)
95{
96 unsigned long flags;
97 void *mssg;
98
99 spin_lock_irqsave(&chan->lock, flags);
100 mssg = chan->active_req;
101 chan->active_req = NULL;
102 spin_unlock_irqrestore(&chan->lock, flags);
103
104 /* Submit next message */
105 msg_submit(chan);
106
107 if (!mssg)
108 return;
109
110 /* Notify the client */
111 if (chan->cl->tx_done)
112 chan->cl->tx_done(chan->cl, mssg, r);
113
114 if (r != -ETIME && chan->cl->tx_block)
115 complete(&chan->tx_complete);
116}
117
118static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer)
119{
120 struct mbox_controller *mbox =
121 container_of(hrtimer, struct mbox_controller, poll_hrt);
122 bool txdone, resched = false;
123 int i;
124 unsigned long flags;
125
126 for (i = 0; i < mbox->num_chans; i++) {
127 struct mbox_chan *chan = &mbox->chans[i];
128
129 if (chan->active_req && chan->cl) {
130 txdone = chan->mbox->ops->last_tx_done(chan);
131 if (txdone)
132 tx_tick(chan, 0);
133 else
134 resched = true;
135 }
136 }
137
138 if (resched) {
139 spin_lock_irqsave(&mbox->poll_hrt_lock, flags);
140 if (!hrtimer_is_queued(hrtimer))
141 hrtimer_forward_now(hrtimer, ms_to_ktime(mbox->txpoll_period));
142 spin_unlock_irqrestore(&mbox->poll_hrt_lock, flags);
143
144 return HRTIMER_RESTART;
145 }
146 return HRTIMER_NORESTART;
147}
148
149/**
150 * mbox_chan_received_data - A way for controller driver to push data
151 * received from remote to the upper layer.
152 * @chan: Pointer to the mailbox channel on which RX happened.
153 * @mssg: Client specific message typecasted as void *
154 *
155 * After startup and before shutdown any data received on the chan
156 * is passed on to the API via atomic mbox_chan_received_data().
157 * The controller should ACK the RX only after this call returns.
158 */
159void mbox_chan_received_data(struct mbox_chan *chan, void *mssg)
160{
161 /* No buffering the received data */
162 if (chan->cl->rx_callback)
163 chan->cl->rx_callback(chan->cl, mssg);
164}
165EXPORT_SYMBOL_GPL(mbox_chan_received_data);
166
167/**
168 * mbox_chan_txdone - A way for controller driver to notify the
169 * framework that the last TX has completed.
170 * @chan: Pointer to the mailbox chan on which TX happened.
171 * @r: Status of last TX - OK or ERROR
172 *
173 * The controller that has IRQ for TX ACK calls this atomic API
174 * to tick the TX state machine. It works only if txdone_irq
175 * is set by the controller.
176 */
177void mbox_chan_txdone(struct mbox_chan *chan, int r)
178{
179 if (unlikely(!(chan->txdone_method & TXDONE_BY_IRQ))) {
180 dev_err(chan->mbox->dev,
181 "Controller can't run the TX ticker\n");
182 return;
183 }
184
185 tx_tick(chan, r);
186}
187EXPORT_SYMBOL_GPL(mbox_chan_txdone);
188
189/**
190 * mbox_client_txdone - The way for a client to run the TX state machine.
191 * @chan: Mailbox channel assigned to this client.
192 * @r: Success status of last transmission.
193 *
194 * The client/protocol had received some 'ACK' packet and it notifies
195 * the API that the last packet was sent successfully. This only works
196 * if the controller can't sense TX-Done.
197 */
198void mbox_client_txdone(struct mbox_chan *chan, int r)
199{
200 if (unlikely(!(chan->txdone_method & TXDONE_BY_ACK))) {
201 dev_err(chan->mbox->dev, "Client can't run the TX ticker\n");
202 return;
203 }
204
205 tx_tick(chan, r);
206}
207EXPORT_SYMBOL_GPL(mbox_client_txdone);
208
209/**
210 * mbox_client_peek_data - A way for client driver to pull data
211 * received from remote by the controller.
212 * @chan: Mailbox channel assigned to this client.
213 *
214 * A poke to controller driver for any received data.
215 * The data is actually passed onto client via the
216 * mbox_chan_received_data()
217 * The call can be made from atomic context, so the controller's
218 * implementation of peek_data() must not sleep.
219 *
220 * Return: True, if controller has, and is going to push after this,
221 * some data.
222 * False, if controller doesn't have any data to be read.
223 */
224bool mbox_client_peek_data(struct mbox_chan *chan)
225{
226 if (chan->mbox->ops->peek_data)
227 return chan->mbox->ops->peek_data(chan);
228
229 return false;
230}
231EXPORT_SYMBOL_GPL(mbox_client_peek_data);
232
233/**
234 * mbox_send_message - For client to submit a message to be
235 * sent to the remote.
236 * @chan: Mailbox channel assigned to this client.
237 * @mssg: Client specific message typecasted.
238 *
239 * For client to submit data to the controller destined for a remote
240 * processor. If the client had set 'tx_block', the call will return
241 * either when the remote receives the data or when 'tx_tout' millisecs
242 * run out.
243 * In non-blocking mode, the requests are buffered by the API and a
244 * non-negative token is returned for each queued request. If the request
245 * is not queued, a negative token is returned. Upon failure or successful
246 * TX, the API calls 'tx_done' from atomic context, from which the client
247 * could submit yet another request.
248 * The pointer to message should be preserved until it is sent
249 * over the chan, i.e, tx_done() is made.
250 * This function could be called from atomic context as it simply
251 * queues the data and returns a token against the request.
252 *
253 * Return: Non-negative integer for successful submission (non-blocking mode)
254 * or transmission over chan (blocking mode).
255 * Negative value denotes failure.
256 */
257int mbox_send_message(struct mbox_chan *chan, void *mssg)
258{
259 int t;
260
261 if (!chan || !chan->cl)
262 return -EINVAL;
263
264 t = add_to_rbuf(chan, mssg);
265 if (t < 0) {
266 dev_err(chan->mbox->dev, "Try increasing MBOX_TX_QUEUE_LEN\n");
267 return t;
268 }
269
270 msg_submit(chan);
271
272 if (chan->cl->tx_block) {
273 unsigned long wait;
274 int ret;
275
276 if (!chan->cl->tx_tout) /* wait forever */
277 wait = msecs_to_jiffies(3600000);
278 else
279 wait = msecs_to_jiffies(chan->cl->tx_tout);
280
281 ret = wait_for_completion_timeout(&chan->tx_complete, wait);
282 if (ret == 0) {
283 t = -ETIME;
284 tx_tick(chan, t);
285 }
286 }
287
288 return t;
289}
290EXPORT_SYMBOL_GPL(mbox_send_message);
291
292/**
293 * mbox_flush - flush a mailbox channel
294 * @chan: mailbox channel to flush
295 * @timeout: time, in milliseconds, to allow the flush operation to succeed
296 *
297 * Mailbox controllers that need to work in atomic context can implement the
298 * ->flush() callback to busy loop until a transmission has been completed.
299 * The implementation must call mbox_chan_txdone() upon success. Clients can
300 * call the mbox_flush() function at any time after mbox_send_message() to
301 * flush the transmission. After the function returns success, the mailbox
302 * transmission is guaranteed to have completed.
303 *
304 * Returns: 0 on success or a negative error code on failure.
305 */
306int mbox_flush(struct mbox_chan *chan, unsigned long timeout)
307{
308 int ret;
309
310 if (!chan->mbox->ops->flush)
311 return -ENOTSUPP;
312
313 ret = chan->mbox->ops->flush(chan, timeout);
314 if (ret < 0)
315 tx_tick(chan, ret);
316
317 return ret;
318}
319EXPORT_SYMBOL_GPL(mbox_flush);
320
321static int __mbox_bind_client(struct mbox_chan *chan, struct mbox_client *cl)
322{
323 struct device *dev = cl->dev;
324 unsigned long flags;
325 int ret;
326
327 if (chan->cl || !try_module_get(chan->mbox->dev->driver->owner)) {
328 dev_dbg(dev, "%s: mailbox not free\n", __func__);
329 return -EBUSY;
330 }
331
332 spin_lock_irqsave(&chan->lock, flags);
333 chan->msg_free = 0;
334 chan->msg_count = 0;
335 chan->active_req = NULL;
336 chan->cl = cl;
337 init_completion(&chan->tx_complete);
338
339 if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
340 chan->txdone_method = TXDONE_BY_ACK;
341
342 spin_unlock_irqrestore(&chan->lock, flags);
343
344 if (chan->mbox->ops->startup) {
345 ret = chan->mbox->ops->startup(chan);
346
347 if (ret) {
348 dev_err(dev, "Unable to startup the chan (%d)\n", ret);
349 mbox_free_channel(chan);
350 return ret;
351 }
352 }
353
354 return 0;
355}
356
357/**
358 * mbox_bind_client - Request a mailbox channel.
359 * @chan: The mailbox channel to bind the client to.
360 * @cl: Identity of the client requesting the channel.
361 *
362 * The Client specifies its requirements and capabilities while asking for
363 * a mailbox channel. It can't be called from atomic context.
364 * The channel is exclusively allocated and can't be used by another
365 * client before the owner calls mbox_free_channel.
366 * After assignment, any packet received on this channel will be
367 * handed over to the client via the 'rx_callback'.
368 * The framework holds reference to the client, so the mbox_client
369 * structure shouldn't be modified until the mbox_free_channel returns.
370 *
371 * Return: 0 if the channel was assigned to the client successfully.
372 * <0 for request failure.
373 */
374int mbox_bind_client(struct mbox_chan *chan, struct mbox_client *cl)
375{
376 int ret;
377
378 mutex_lock(&con_mutex);
379 ret = __mbox_bind_client(chan, cl);
380 mutex_unlock(&con_mutex);
381
382 return ret;
383}
384EXPORT_SYMBOL_GPL(mbox_bind_client);
385
386/**
387 * mbox_request_channel - Request a mailbox channel.
388 * @cl: Identity of the client requesting the channel.
389 * @index: Index of mailbox specifier in 'mboxes' property.
390 *
391 * The Client specifies its requirements and capabilities while asking for
392 * a mailbox channel. It can't be called from atomic context.
393 * The channel is exclusively allocated and can't be used by another
394 * client before the owner calls mbox_free_channel.
395 * After assignment, any packet received on this channel will be
396 * handed over to the client via the 'rx_callback'.
397 * The framework holds reference to the client, so the mbox_client
398 * structure shouldn't be modified until the mbox_free_channel returns.
399 *
400 * Return: Pointer to the channel assigned to the client if successful.
401 * ERR_PTR for request failure.
402 */
403struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
404{
405 struct device *dev = cl->dev;
406 struct mbox_controller *mbox;
407 struct of_phandle_args spec;
408 struct mbox_chan *chan;
409 int ret;
410
411 if (!dev || !dev->of_node) {
412 pr_debug("%s: No owner device node\n", __func__);
413 return ERR_PTR(-ENODEV);
414 }
415
416 mutex_lock(&con_mutex);
417
418 if (of_parse_phandle_with_args(dev->of_node, "mboxes",
419 "#mbox-cells", index, &spec)) {
420 dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__);
421 mutex_unlock(&con_mutex);
422 return ERR_PTR(-ENODEV);
423 }
424
425 chan = ERR_PTR(-EPROBE_DEFER);
426 list_for_each_entry(mbox, &mbox_cons, node)
427 if (mbox->dev->of_node == spec.np) {
428 chan = mbox->of_xlate(mbox, &spec);
429 if (!IS_ERR(chan))
430 break;
431 }
432
433 of_node_put(spec.np);
434
435 if (IS_ERR(chan)) {
436 mutex_unlock(&con_mutex);
437 return chan;
438 }
439
440 ret = __mbox_bind_client(chan, cl);
441 if (ret)
442 chan = ERR_PTR(ret);
443
444 mutex_unlock(&con_mutex);
445 return chan;
446}
447EXPORT_SYMBOL_GPL(mbox_request_channel);
448
449struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl,
450 const char *name)
451{
452 struct device_node *np = cl->dev->of_node;
453 struct property *prop;
454 const char *mbox_name;
455 int index = 0;
456
457 if (!np) {
458 dev_err(cl->dev, "%s() currently only supports DT\n", __func__);
459 return ERR_PTR(-EINVAL);
460 }
461
462 if (!of_get_property(np, "mbox-names", NULL)) {
463 dev_err(cl->dev,
464 "%s() requires an \"mbox-names\" property\n", __func__);
465 return ERR_PTR(-EINVAL);
466 }
467
468 of_property_for_each_string(np, "mbox-names", prop, mbox_name) {
469 if (!strncmp(name, mbox_name, strlen(name)))
470 return mbox_request_channel(cl, index);
471 index++;
472 }
473
474 dev_err(cl->dev, "%s() could not locate channel named \"%s\"\n",
475 __func__, name);
476 return ERR_PTR(-EINVAL);
477}
478EXPORT_SYMBOL_GPL(mbox_request_channel_byname);
479
480/**
481 * mbox_free_channel - The client relinquishes control of a mailbox
482 * channel by this call.
483 * @chan: The mailbox channel to be freed.
484 */
485void mbox_free_channel(struct mbox_chan *chan)
486{
487 unsigned long flags;
488
489 if (!chan || !chan->cl)
490 return;
491
492 if (chan->mbox->ops->shutdown)
493 chan->mbox->ops->shutdown(chan);
494
495 /* The queued TX requests are simply aborted, no callbacks are made */
496 spin_lock_irqsave(&chan->lock, flags);
497 chan->cl = NULL;
498 chan->active_req = NULL;
499 if (chan->txdone_method == TXDONE_BY_ACK)
500 chan->txdone_method = TXDONE_BY_POLL;
501
502 module_put(chan->mbox->dev->driver->owner);
503 spin_unlock_irqrestore(&chan->lock, flags);
504}
505EXPORT_SYMBOL_GPL(mbox_free_channel);
506
507static struct mbox_chan *
508of_mbox_index_xlate(struct mbox_controller *mbox,
509 const struct of_phandle_args *sp)
510{
511 int ind = sp->args[0];
512
513 if (ind >= mbox->num_chans)
514 return ERR_PTR(-EINVAL);
515
516 return &mbox->chans[ind];
517}
518
519/**
520 * mbox_controller_register - Register the mailbox controller
521 * @mbox: Pointer to the mailbox controller.
522 *
523 * The controller driver registers its communication channels
524 */
525int mbox_controller_register(struct mbox_controller *mbox)
526{
527 int i, txdone;
528
529 /* Sanity check */
530 if (!mbox || !mbox->dev || !mbox->ops || !mbox->num_chans)
531 return -EINVAL;
532
533 if (mbox->txdone_irq)
534 txdone = TXDONE_BY_IRQ;
535 else if (mbox->txdone_poll)
536 txdone = TXDONE_BY_POLL;
537 else /* It has to be ACK then */
538 txdone = TXDONE_BY_ACK;
539
540 if (txdone == TXDONE_BY_POLL) {
541
542 if (!mbox->ops->last_tx_done) {
543 dev_err(mbox->dev, "last_tx_done method is absent\n");
544 return -EINVAL;
545 }
546
547 hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC,
548 HRTIMER_MODE_REL);
549 mbox->poll_hrt.function = txdone_hrtimer;
550 spin_lock_init(&mbox->poll_hrt_lock);
551 }
552
553 for (i = 0; i < mbox->num_chans; i++) {
554 struct mbox_chan *chan = &mbox->chans[i];
555
556 chan->cl = NULL;
557 chan->mbox = mbox;
558 chan->txdone_method = txdone;
559 spin_lock_init(&chan->lock);
560 }
561
562 if (!mbox->of_xlate)
563 mbox->of_xlate = of_mbox_index_xlate;
564
565 mutex_lock(&con_mutex);
566 list_add_tail(&mbox->node, &mbox_cons);
567 mutex_unlock(&con_mutex);
568
569 return 0;
570}
571EXPORT_SYMBOL_GPL(mbox_controller_register);
572
573/**
574 * mbox_controller_unregister - Unregister the mailbox controller
575 * @mbox: Pointer to the mailbox controller.
576 */
577void mbox_controller_unregister(struct mbox_controller *mbox)
578{
579 int i;
580
581 if (!mbox)
582 return;
583
584 mutex_lock(&con_mutex);
585
586 list_del(&mbox->node);
587
588 for (i = 0; i < mbox->num_chans; i++)
589 mbox_free_channel(&mbox->chans[i]);
590
591 if (mbox->txdone_poll)
592 hrtimer_cancel(&mbox->poll_hrt);
593
594 mutex_unlock(&con_mutex);
595}
596EXPORT_SYMBOL_GPL(mbox_controller_unregister);
597
598static void __devm_mbox_controller_unregister(struct device *dev, void *res)
599{
600 struct mbox_controller **mbox = res;
601
602 mbox_controller_unregister(*mbox);
603}
604
605static int devm_mbox_controller_match(struct device *dev, void *res, void *data)
606{
607 struct mbox_controller **mbox = res;
608
609 if (WARN_ON(!mbox || !*mbox))
610 return 0;
611
612 return *mbox == data;
613}
614
615/**
616 * devm_mbox_controller_register() - managed mbox_controller_register()
617 * @dev: device owning the mailbox controller being registered
618 * @mbox: mailbox controller being registered
619 *
620 * This function adds a device-managed resource that will make sure that the
621 * mailbox controller, which is registered using mbox_controller_register()
622 * as part of this function, will be unregistered along with the rest of
623 * device-managed resources upon driver probe failure or driver removal.
624 *
625 * Returns 0 on success or a negative error code on failure.
626 */
627int devm_mbox_controller_register(struct device *dev,
628 struct mbox_controller *mbox)
629{
630 struct mbox_controller **ptr;
631 int err;
632
633 ptr = devres_alloc(__devm_mbox_controller_unregister, sizeof(*ptr),
634 GFP_KERNEL);
635 if (!ptr)
636 return -ENOMEM;
637
638 err = mbox_controller_register(mbox);
639 if (err < 0) {
640 devres_free(ptr);
641 return err;
642 }
643
644 devres_add(dev, ptr);
645 *ptr = mbox;
646
647 return 0;
648}
649EXPORT_SYMBOL_GPL(devm_mbox_controller_register);
650
651/**
652 * devm_mbox_controller_unregister() - managed mbox_controller_unregister()
653 * @dev: device owning the mailbox controller being unregistered
654 * @mbox: mailbox controller being unregistered
655 *
656 * This function unregisters the mailbox controller and removes the device-
657 * managed resource that was set up to automatically unregister the mailbox
658 * controller on driver probe failure or driver removal. It's typically not
659 * necessary to call this function.
660 */
661void devm_mbox_controller_unregister(struct device *dev, struct mbox_controller *mbox)
662{
663 WARN_ON(devres_release(dev, __devm_mbox_controller_unregister,
664 devm_mbox_controller_match, mbox));
665}
666EXPORT_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, ktime_set(0, 0),
91 HRTIMER_MODE_REL);
92}
93
94static void tx_tick(struct mbox_chan *chan, int r)
95{
96 unsigned long flags;
97 void *mssg;
98
99 spin_lock_irqsave(&chan->lock, flags);
100 mssg = chan->active_req;
101 chan->active_req = NULL;
102 spin_unlock_irqrestore(&chan->lock, flags);
103
104 /* Submit next message */
105 msg_submit(chan);
106
107 /* Notify the client */
108 if (mssg && chan->cl->tx_done)
109 chan->cl->tx_done(chan->cl, mssg, r);
110
111 if (chan->cl->tx_block)
112 complete(&chan->tx_complete);
113}
114
115static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer)
116{
117 struct mbox_controller *mbox =
118 container_of(hrtimer, struct mbox_controller, poll_hrt);
119 bool txdone, resched = false;
120 int i;
121
122 for (i = 0; i < mbox->num_chans; i++) {
123 struct mbox_chan *chan = &mbox->chans[i];
124
125 if (chan->active_req && chan->cl) {
126 txdone = chan->mbox->ops->last_tx_done(chan);
127 if (txdone)
128 tx_tick(chan, 0);
129 else
130 resched = true;
131 }
132 }
133
134 if (resched) {
135 hrtimer_forward_now(hrtimer, ms_to_ktime(mbox->txpoll_period));
136 return HRTIMER_RESTART;
137 }
138 return HRTIMER_NORESTART;
139}
140
141/**
142 * mbox_chan_received_data - A way for controller driver to push data
143 * received from remote to the upper layer.
144 * @chan: Pointer to the mailbox channel on which RX happened.
145 * @mssg: Client specific message typecasted as void *
146 *
147 * After startup and before shutdown any data received on the chan
148 * is passed on to the API via atomic mbox_chan_received_data().
149 * The controller should ACK the RX only after this call returns.
150 */
151void mbox_chan_received_data(struct mbox_chan *chan, void *mssg)
152{
153 /* No buffering the received data */
154 if (chan->cl->rx_callback)
155 chan->cl->rx_callback(chan->cl, mssg);
156}
157EXPORT_SYMBOL_GPL(mbox_chan_received_data);
158
159/**
160 * mbox_chan_txdone - A way for controller driver to notify the
161 * framework that the last TX has completed.
162 * @chan: Pointer to the mailbox chan on which TX happened.
163 * @r: Status of last TX - OK or ERROR
164 *
165 * The controller that has IRQ for TX ACK calls this atomic API
166 * to tick the TX state machine. It works only if txdone_irq
167 * is set by the controller.
168 */
169void mbox_chan_txdone(struct mbox_chan *chan, int r)
170{
171 if (unlikely(!(chan->txdone_method & TXDONE_BY_IRQ))) {
172 dev_err(chan->mbox->dev,
173 "Controller can't run the TX ticker\n");
174 return;
175 }
176
177 tx_tick(chan, r);
178}
179EXPORT_SYMBOL_GPL(mbox_chan_txdone);
180
181/**
182 * mbox_client_txdone - The way for a client to run the TX state machine.
183 * @chan: Mailbox channel assigned to this client.
184 * @r: Success status of last transmission.
185 *
186 * The client/protocol had received some 'ACK' packet and it notifies
187 * the API that the last packet was sent successfully. This only works
188 * if the controller can't sense TX-Done.
189 */
190void mbox_client_txdone(struct mbox_chan *chan, int r)
191{
192 if (unlikely(!(chan->txdone_method & TXDONE_BY_ACK))) {
193 dev_err(chan->mbox->dev, "Client can't run the TX ticker\n");
194 return;
195 }
196
197 tx_tick(chan, r);
198}
199EXPORT_SYMBOL_GPL(mbox_client_txdone);
200
201/**
202 * mbox_client_peek_data - A way for client driver to pull data
203 * received from remote by the controller.
204 * @chan: Mailbox channel assigned to this client.
205 *
206 * A poke to controller driver for any received data.
207 * The data is actually passed onto client via the
208 * mbox_chan_received_data()
209 * The call can be made from atomic context, so the controller's
210 * implementation of peek_data() must not sleep.
211 *
212 * Return: True, if controller has, and is going to push after this,
213 * some data.
214 * False, if controller doesn't have any data to be read.
215 */
216bool mbox_client_peek_data(struct mbox_chan *chan)
217{
218 if (chan->mbox->ops->peek_data)
219 return chan->mbox->ops->peek_data(chan);
220
221 return false;
222}
223EXPORT_SYMBOL_GPL(mbox_client_peek_data);
224
225/**
226 * mbox_send_message - For client to submit a message to be
227 * sent to the remote.
228 * @chan: Mailbox channel assigned to this client.
229 * @mssg: Client specific message typecasted.
230 *
231 * For client to submit data to the controller destined for a remote
232 * processor. If the client had set 'tx_block', the call will return
233 * either when the remote receives the data or when 'tx_tout' millisecs
234 * run out.
235 * In non-blocking mode, the requests are buffered by the API and a
236 * non-negative token is returned for each queued request. If the request
237 * is not queued, a negative token is returned. Upon failure or successful
238 * TX, the API calls 'tx_done' from atomic context, from which the client
239 * could submit yet another request.
240 * The pointer to message should be preserved until it is sent
241 * over the chan, i.e, tx_done() is made.
242 * This function could be called from atomic context as it simply
243 * queues the data and returns a token against the request.
244 *
245 * Return: Non-negative integer for successful submission (non-blocking mode)
246 * or transmission over chan (blocking mode).
247 * Negative value denotes failure.
248 */
249int mbox_send_message(struct mbox_chan *chan, void *mssg)
250{
251 int t;
252
253 if (!chan || !chan->cl)
254 return -EINVAL;
255
256 t = add_to_rbuf(chan, mssg);
257 if (t < 0) {
258 dev_err(chan->mbox->dev, "Try increasing MBOX_TX_QUEUE_LEN\n");
259 return t;
260 }
261
262 msg_submit(chan);
263
264 if (chan->cl->tx_block && chan->active_req) {
265 unsigned long wait;
266 int ret;
267
268 if (!chan->cl->tx_tout) /* wait forever */
269 wait = msecs_to_jiffies(3600000);
270 else
271 wait = msecs_to_jiffies(chan->cl->tx_tout);
272
273 ret = wait_for_completion_timeout(&chan->tx_complete, wait);
274 if (ret == 0) {
275 t = -EIO;
276 tx_tick(chan, -EIO);
277 }
278 }
279
280 return t;
281}
282EXPORT_SYMBOL_GPL(mbox_send_message);
283
284/**
285 * mbox_request_channel - Request a mailbox channel.
286 * @cl: Identity of the client requesting the channel.
287 * @index: Index of mailbox specifier in 'mboxes' property.
288 *
289 * The Client specifies its requirements and capabilities while asking for
290 * a mailbox channel. It can't be called from atomic context.
291 * The channel is exclusively allocated and can't be used by another
292 * client before the owner calls mbox_free_channel.
293 * After assignment, any packet received on this channel will be
294 * handed over to the client via the 'rx_callback'.
295 * The framework holds reference to the client, so the mbox_client
296 * structure shouldn't be modified until the mbox_free_channel returns.
297 *
298 * Return: Pointer to the channel assigned to the client if successful.
299 * ERR_PTR for request failure.
300 */
301struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
302{
303 struct device *dev = cl->dev;
304 struct mbox_controller *mbox;
305 struct of_phandle_args spec;
306 struct mbox_chan *chan;
307 unsigned long flags;
308 int ret;
309
310 if (!dev || !dev->of_node) {
311 pr_debug("%s: No owner device node\n", __func__);
312 return ERR_PTR(-ENODEV);
313 }
314
315 mutex_lock(&con_mutex);
316
317 if (of_parse_phandle_with_args(dev->of_node, "mboxes",
318 "#mbox-cells", index, &spec)) {
319 dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__);
320 mutex_unlock(&con_mutex);
321 return ERR_PTR(-ENODEV);
322 }
323
324 chan = ERR_PTR(-EPROBE_DEFER);
325 list_for_each_entry(mbox, &mbox_cons, node)
326 if (mbox->dev->of_node == spec.np) {
327 chan = mbox->of_xlate(mbox, &spec);
328 break;
329 }
330
331 of_node_put(spec.np);
332
333 if (IS_ERR(chan)) {
334 mutex_unlock(&con_mutex);
335 return chan;
336 }
337
338 if (chan->cl || !try_module_get(mbox->dev->driver->owner)) {
339 dev_dbg(dev, "%s: mailbox not free\n", __func__);
340 mutex_unlock(&con_mutex);
341 return ERR_PTR(-EBUSY);
342 }
343
344 spin_lock_irqsave(&chan->lock, flags);
345 chan->msg_free = 0;
346 chan->msg_count = 0;
347 chan->active_req = NULL;
348 chan->cl = cl;
349 init_completion(&chan->tx_complete);
350
351 if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
352 chan->txdone_method |= TXDONE_BY_ACK;
353
354 spin_unlock_irqrestore(&chan->lock, flags);
355
356 ret = chan->mbox->ops->startup(chan);
357 if (ret) {
358 dev_err(dev, "Unable to startup the chan (%d)\n", ret);
359 mbox_free_channel(chan);
360 chan = ERR_PTR(ret);
361 }
362
363 mutex_unlock(&con_mutex);
364 return chan;
365}
366EXPORT_SYMBOL_GPL(mbox_request_channel);
367
368struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl,
369 const char *name)
370{
371 struct device_node *np = cl->dev->of_node;
372 struct property *prop;
373 const char *mbox_name;
374 int index = 0;
375
376 if (!np) {
377 dev_err(cl->dev, "%s() currently only supports DT\n", __func__);
378 return ERR_PTR(-EINVAL);
379 }
380
381 if (!of_get_property(np, "mbox-names", NULL)) {
382 dev_err(cl->dev,
383 "%s() requires an \"mbox-names\" property\n", __func__);
384 return ERR_PTR(-EINVAL);
385 }
386
387 of_property_for_each_string(np, "mbox-names", prop, mbox_name) {
388 if (!strncmp(name, mbox_name, strlen(name)))
389 break;
390 index++;
391 }
392
393 return mbox_request_channel(cl, index);
394}
395EXPORT_SYMBOL_GPL(mbox_request_channel_byname);
396
397/**
398 * mbox_free_channel - The client relinquishes control of a mailbox
399 * channel by this call.
400 * @chan: The mailbox channel to be freed.
401 */
402void mbox_free_channel(struct mbox_chan *chan)
403{
404 unsigned long flags;
405
406 if (!chan || !chan->cl)
407 return;
408
409 chan->mbox->ops->shutdown(chan);
410
411 /* The queued TX requests are simply aborted, no callbacks are made */
412 spin_lock_irqsave(&chan->lock, flags);
413 chan->cl = NULL;
414 chan->active_req = NULL;
415 if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
416 chan->txdone_method = TXDONE_BY_POLL;
417
418 module_put(chan->mbox->dev->driver->owner);
419 spin_unlock_irqrestore(&chan->lock, flags);
420}
421EXPORT_SYMBOL_GPL(mbox_free_channel);
422
423static struct mbox_chan *
424of_mbox_index_xlate(struct mbox_controller *mbox,
425 const struct of_phandle_args *sp)
426{
427 int ind = sp->args[0];
428
429 if (ind >= mbox->num_chans)
430 return ERR_PTR(-EINVAL);
431
432 return &mbox->chans[ind];
433}
434
435/**
436 * mbox_controller_register - Register the mailbox controller
437 * @mbox: Pointer to the mailbox controller.
438 *
439 * The controller driver registers its communication channels
440 */
441int mbox_controller_register(struct mbox_controller *mbox)
442{
443 int i, txdone;
444
445 /* Sanity check */
446 if (!mbox || !mbox->dev || !mbox->ops || !mbox->num_chans)
447 return -EINVAL;
448
449 if (mbox->txdone_irq)
450 txdone = TXDONE_BY_IRQ;
451 else if (mbox->txdone_poll)
452 txdone = TXDONE_BY_POLL;
453 else /* It has to be ACK then */
454 txdone = TXDONE_BY_ACK;
455
456 if (txdone == TXDONE_BY_POLL) {
457 hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC,
458 HRTIMER_MODE_REL);
459 mbox->poll_hrt.function = txdone_hrtimer;
460 }
461
462 for (i = 0; i < mbox->num_chans; i++) {
463 struct mbox_chan *chan = &mbox->chans[i];
464
465 chan->cl = NULL;
466 chan->mbox = mbox;
467 chan->txdone_method = txdone;
468 spin_lock_init(&chan->lock);
469 }
470
471 if (!mbox->of_xlate)
472 mbox->of_xlate = of_mbox_index_xlate;
473
474 mutex_lock(&con_mutex);
475 list_add_tail(&mbox->node, &mbox_cons);
476 mutex_unlock(&con_mutex);
477
478 return 0;
479}
480EXPORT_SYMBOL_GPL(mbox_controller_register);
481
482/**
483 * mbox_controller_unregister - Unregister the mailbox controller
484 * @mbox: Pointer to the mailbox controller.
485 */
486void mbox_controller_unregister(struct mbox_controller *mbox)
487{
488 int i;
489
490 if (!mbox)
491 return;
492
493 mutex_lock(&con_mutex);
494
495 list_del(&mbox->node);
496
497 for (i = 0; i < mbox->num_chans; i++)
498 mbox_free_channel(&mbox->chans[i]);
499
500 if (mbox->txdone_poll)
501 hrtimer_cancel(&mbox->poll_hrt);
502
503 mutex_unlock(&con_mutex);
504}
505EXPORT_SYMBOL_GPL(mbox_controller_unregister);