blob: 4a36632c236f09ad9cdde06ff213961c712c3000 [file] [log] [blame]
Jassi Brar2b6d83e2014-06-12 22:31:19 +05301/*
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
Ashwin Chaugule86c22f82014-11-12 19:59:38 -050024#include "mailbox.h"
Jassi Brar2b6d83e2014-06-12 22:31:19 +053025
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;
Andrew Bresticker52a49302014-10-30 13:01:07 -070061 int err = -EBUSY;
Jassi Brar2b6d83e2014-06-12 22:31:19 +053062
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
Sudeep Holla97b0c7b2014-11-11 18:33:01 +000077 if (chan->cl->tx_prepare)
78 chan->cl->tx_prepare(chan->cl, data);
Jassi Brar2b6d83e2014-06-12 22:31:19 +053079 /* 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);
Andrew Bresticker52a49302014-10-30 13:01:07 -070087
Jassi Brar01340df2014-12-12 15:22:49 +053088 if (!err && (chan->txdone_method & TXDONE_BY_POLL))
Sudeep Holla0cc67942015-07-31 11:48:05 +010089 /* kick start the timer immediately to avoid delays */
90 hrtimer_start(&chan->mbox->poll_hrt, ktime_set(0, 0),
91 HRTIMER_MODE_REL);
Jassi Brar2b6d83e2014-06-12 22:31:19 +053092}
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
Sudeep Holla0cc67942015-07-31 11:48:05 +0100115static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer)
Jassi Brar2b6d83e2014-06-12 22:31:19 +0530116{
Sudeep Holla0cc67942015-07-31 11:48:05 +0100117 struct mbox_controller *mbox =
118 container_of(hrtimer, struct mbox_controller, poll_hrt);
Jassi Brar2b6d83e2014-06-12 22:31:19 +0530119 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) {
Jassi Brar2b6d83e2014-06-12 22:31:19 +0530126 txdone = chan->mbox->ops->last_tx_done(chan);
127 if (txdone)
128 tx_tick(chan, 0);
Andrew Bresticker52a49302014-10-30 13:01:07 -0700129 else
130 resched = true;
Jassi Brar2b6d83e2014-06-12 22:31:19 +0530131 }
132 }
133
Sudeep Holla0cc67942015-07-31 11:48:05 +0100134 if (resched) {
135 hrtimer_forward_now(hrtimer, ms_to_ktime(mbox->txpoll_period));
136 return HRTIMER_RESTART;
137 }
138 return HRTIMER_NORESTART;
Jassi Brar2b6d83e2014-06-12 22:31:19 +0530139}
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
Jassi Brar2b6d83e2014-06-12 22:31:19 +0530264 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
Benson Leung2d805fc2015-05-04 10:36:36 -0700324 chan = ERR_PTR(-EPROBE_DEFER);
Jassi Brar2b6d83e2014-06-12 22:31:19 +0530325 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
Benson Leung2d805fc2015-05-04 10:36:36 -0700333 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)) {
Jassi Brar2b6d83e2014-06-12 22:31:19 +0530339 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
Lee Jonesdfabde22015-05-11 17:08:50 +0100368struct 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__);
Lee Jones0c44d782016-03-23 14:43:43 +0000378 return ERR_PTR(-EINVAL);
Lee Jonesdfabde22015-05-11 17:08:50 +0100379 }
380
381 if (!of_get_property(np, "mbox-names", NULL)) {
382 dev_err(cl->dev,
383 "%s() requires an \"mbox-names\" property\n", __func__);
Lee Jones0c44d782016-03-23 14:43:43 +0000384 return ERR_PTR(-EINVAL);
Lee Jonesdfabde22015-05-11 17:08:50 +0100385 }
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
Jassi Brar2b6d83e2014-06-12 22:31:19 +0530397/**
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)
Benson Leung2d805fc2015-05-04 10:36:36 -0700430 return ERR_PTR(-EINVAL);
Jassi Brar2b6d83e2014-06-12 22:31:19 +0530431
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) {
Sudeep Holla0cc67942015-07-31 11:48:05 +0100457 hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC,
458 HRTIMER_MODE_REL);
459 mbox->poll_hrt.function = txdone_hrtimer;
Jassi Brar2b6d83e2014-06-12 22:31:19 +0530460 }
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)
Sudeep Holla0cc67942015-07-31 11:48:05 +0100501 hrtimer_cancel(&mbox->poll_hrt);
Jassi Brar2b6d83e2014-06-12 22:31:19 +0530502
503 mutex_unlock(&con_mutex);
504}
505EXPORT_SYMBOL_GPL(mbox_controller_unregister);