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2b6d83e2 JB |
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 | ||
86c22f8c | 24 | #include "mailbox.h" |
2b6d83e2 JB |
25 | |
26 | static LIST_HEAD(mbox_cons); | |
27 | static DEFINE_MUTEX(con_mutex); | |
28 | ||
29 | static 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 | ||
56 | static void msg_submit(struct mbox_chan *chan) | |
57 | { | |
58 | unsigned count, idx; | |
59 | unsigned long flags; | |
60 | void *data; | |
52a49306 | 61 | int err = -EBUSY; |
2b6d83e2 JB |
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 | ||
97b0c7bd SH |
77 | if (chan->cl->tx_prepare) |
78 | chan->cl->tx_prepare(chan->cl, data); | |
2b6d83e2 JB |
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 | } | |
85 | exit: | |
86 | spin_unlock_irqrestore(&chan->lock, flags); | |
52a49306 | 87 | |
01340df8 | 88 | if (!err && (chan->txdone_method & TXDONE_BY_POLL)) |
0cc67945 | 89 | /* kick start the timer immediately to avoid delays */ |
8b0e1953 | 90 | hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL); |
2b6d83e2 JB |
91 | } |
92 | ||
93 | static 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 | ||
cb710ab1 SH |
106 | if (!mssg) |
107 | return; | |
108 | ||
2b6d83e2 | 109 | /* Notify the client */ |
cb710ab1 | 110 | if (chan->cl->tx_done) |
2b6d83e2 JB |
111 | chan->cl->tx_done(chan->cl, mssg, r); |
112 | ||
cc6eeaa3 | 113 | if (r != -ETIME && chan->cl->tx_block) |
2b6d83e2 JB |
114 | complete(&chan->tx_complete); |
115 | } | |
116 | ||
0cc67945 | 117 | static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer) |
2b6d83e2 | 118 | { |
0cc67945 SH |
119 | struct mbox_controller *mbox = |
120 | container_of(hrtimer, struct mbox_controller, poll_hrt); | |
2b6d83e2 JB |
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) { | |
2b6d83e2 JB |
128 | txdone = chan->mbox->ops->last_tx_done(chan); |
129 | if (txdone) | |
130 | tx_tick(chan, 0); | |
52a49306 AB |
131 | else |
132 | resched = true; | |
2b6d83e2 JB |
133 | } |
134 | } | |
135 | ||
0cc67945 SH |
136 | if (resched) { |
137 | hrtimer_forward_now(hrtimer, ms_to_ktime(mbox->txpoll_period)); | |
138 | return HRTIMER_RESTART; | |
139 | } | |
140 | return HRTIMER_NORESTART; | |
2b6d83e2 JB |
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 | */ | |
153 | void 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 | } | |
159 | EXPORT_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 | */ | |
171 | void 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 | } | |
181 | EXPORT_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 | */ | |
192 | void 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 | } | |
201 | EXPORT_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 | */ | |
218 | bool 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 | } | |
225 | EXPORT_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 | */ | |
251 | int 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 | ||
c61b781e | 266 | if (chan->cl->tx_block) { |
2b6d83e2 JB |
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) { | |
cc6eeaa3 SH |
277 | t = -ETIME; |
278 | tx_tick(chan, t); | |
2b6d83e2 JB |
279 | } |
280 | } | |
281 | ||
282 | return t; | |
283 | } | |
284 | EXPORT_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 | */ | |
303 | struct 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 | ||
2d805fc1 | 326 | chan = ERR_PTR(-EPROBE_DEFER); |
2b6d83e2 JB |
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 | ||
2d805fc1 BL |
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)) { | |
2b6d83e2 JB |
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 | ||
b7133d6f BA |
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 | } | |
2b6d83e2 JB |
366 | } |
367 | ||
368 | mutex_unlock(&con_mutex); | |
369 | return chan; | |
370 | } | |
371 | EXPORT_SYMBOL_GPL(mbox_request_channel); | |
372 | ||
dfabde20 LJ |
373 | struct 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__); | |
0c44d789 | 383 | return ERR_PTR(-EINVAL); |
dfabde20 LJ |
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__); | |
0c44d789 | 389 | return ERR_PTR(-EINVAL); |
dfabde20 LJ |
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 | } | |
400 | EXPORT_SYMBOL_GPL(mbox_request_channel_byname); | |
401 | ||
2b6d83e2 JB |
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 | */ | |
407 | void mbox_free_channel(struct mbox_chan *chan) | |
408 | { | |
409 | unsigned long flags; | |
410 | ||
411 | if (!chan || !chan->cl) | |
412 | return; | |
413 | ||
b7133d6f BA |
414 | if (chan->mbox->ops->shutdown) |
415 | chan->mbox->ops->shutdown(chan); | |
2b6d83e2 JB |
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_POLL | 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 | } | |
427 | EXPORT_SYMBOL_GPL(mbox_free_channel); | |
428 | ||
429 | static struct mbox_chan * | |
430 | of_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) | |
2d805fc1 | 436 | return ERR_PTR(-EINVAL); |
2b6d83e2 JB |
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 | */ | |
447 | int 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) { | |
4605fff0 AK |
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 | ||
0cc67945 SH |
469 | hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC, |
470 | HRTIMER_MODE_REL); | |
471 | mbox->poll_hrt.function = txdone_hrtimer; | |
2b6d83e2 JB |
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 | } | |
492 | EXPORT_SYMBOL_GPL(mbox_controller_register); | |
493 | ||
494 | /** | |
495 | * mbox_controller_unregister - Unregister the mailbox controller | |
496 | * @mbox: Pointer to the mailbox controller. | |
497 | */ | |
498 | void 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) | |
0cc67945 | 513 | hrtimer_cancel(&mbox->poll_hrt); |
2b6d83e2 JB |
514 | |
515 | mutex_unlock(&con_mutex); | |
516 | } | |
517 | EXPORT_SYMBOL_GPL(mbox_controller_unregister); |