2 * Mailbox: Common code for Mailbox controllers and users
4 * Copyright (C) 2013-2014 Linaro Ltd.
5 * Author: Jassi Brar <jassisinghbrar@gmail.com>
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.
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>
26 static LIST_HEAD(mbox_cons);
27 static DEFINE_MUTEX(con_mutex);
29 static int add_to_rbuf(struct mbox_chan *chan, void *mssg)
34 spin_lock_irqsave(&chan->lock, flags);
36 /* See if there is any space left */
37 if (chan->msg_count == MBOX_TX_QUEUE_LEN) {
38 spin_unlock_irqrestore(&chan->lock, flags);
43 chan->msg_data[idx] = mssg;
46 if (idx == MBOX_TX_QUEUE_LEN - 1)
51 spin_unlock_irqrestore(&chan->lock, flags);
56 static void msg_submit(struct mbox_chan *chan)
63 spin_lock_irqsave(&chan->lock, flags);
65 if (!chan->msg_count || chan->active_req)
68 count = chan->msg_count;
73 idx += MBOX_TX_QUEUE_LEN - count;
75 data = chan->msg_data[idx];
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);
82 chan->active_req = data;
86 spin_unlock_irqrestore(&chan->lock, flags);
88 if (!err && (chan->txdone_method & TXDONE_BY_POLL)) {
89 /* kick start the timer immediately to avoid delays */
90 spin_lock_irqsave(&chan->mbox->poll_hrt_lock, flags);
91 hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL);
92 spin_unlock_irqrestore(&chan->mbox->poll_hrt_lock, flags);
96 static void tx_tick(struct mbox_chan *chan, int r)
101 spin_lock_irqsave(&chan->lock, flags);
102 mssg = chan->active_req;
103 chan->active_req = NULL;
104 spin_unlock_irqrestore(&chan->lock, flags);
106 /* Submit next message */
112 /* Notify the client */
113 if (chan->cl->tx_done)
114 chan->cl->tx_done(chan->cl, mssg, r);
116 if (r != -ETIME && chan->cl->tx_block)
117 complete(&chan->tx_complete);
120 static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer)
122 struct mbox_controller *mbox =
123 container_of(hrtimer, struct mbox_controller, poll_hrt);
124 bool txdone, resched = false;
128 for (i = 0; i < mbox->num_chans; i++) {
129 struct mbox_chan *chan = &mbox->chans[i];
131 if (chan->active_req && chan->cl) {
132 txdone = chan->mbox->ops->last_tx_done(chan);
141 spin_lock_irqsave(&mbox->poll_hrt_lock, flags);
142 if (!hrtimer_is_queued(hrtimer))
143 hrtimer_forward_now(hrtimer, ms_to_ktime(mbox->txpoll_period));
144 spin_unlock_irqrestore(&mbox->poll_hrt_lock, flags);
146 return HRTIMER_RESTART;
148 return HRTIMER_NORESTART;
152 * mbox_chan_received_data - A way for controller driver to push data
153 * received from remote to the upper layer.
154 * @chan: Pointer to the mailbox channel on which RX happened.
155 * @mssg: Client specific message typecasted as void *
157 * After startup and before shutdown any data received on the chan
158 * is passed on to the API via atomic mbox_chan_received_data().
159 * The controller should ACK the RX only after this call returns.
161 void mbox_chan_received_data(struct mbox_chan *chan, void *mssg)
163 /* No buffering the received data */
164 if (chan->cl->rx_callback)
165 chan->cl->rx_callback(chan->cl, mssg);
167 EXPORT_SYMBOL_GPL(mbox_chan_received_data);
170 * mbox_chan_txdone - A way for controller driver to notify the
171 * framework that the last TX has completed.
172 * @chan: Pointer to the mailbox chan on which TX happened.
173 * @r: Status of last TX - OK or ERROR
175 * The controller that has IRQ for TX ACK calls this atomic API
176 * to tick the TX state machine. It works only if txdone_irq
177 * is set by the controller.
179 void mbox_chan_txdone(struct mbox_chan *chan, int r)
181 if (unlikely(!(chan->txdone_method & TXDONE_BY_IRQ))) {
182 dev_err(chan->mbox->dev,
183 "Controller can't run the TX ticker\n");
189 EXPORT_SYMBOL_GPL(mbox_chan_txdone);
192 * mbox_client_txdone - The way for a client to run the TX state machine.
193 * @chan: Mailbox channel assigned to this client.
194 * @r: Success status of last transmission.
196 * The client/protocol had received some 'ACK' packet and it notifies
197 * the API that the last packet was sent successfully. This only works
198 * if the controller can't sense TX-Done.
200 void mbox_client_txdone(struct mbox_chan *chan, int r)
202 if (unlikely(!(chan->txdone_method & TXDONE_BY_ACK))) {
203 dev_err(chan->mbox->dev, "Client can't run the TX ticker\n");
209 EXPORT_SYMBOL_GPL(mbox_client_txdone);
212 * mbox_client_peek_data - A way for client driver to pull data
213 * received from remote by the controller.
214 * @chan: Mailbox channel assigned to this client.
216 * A poke to controller driver for any received data.
217 * The data is actually passed onto client via the
218 * mbox_chan_received_data()
219 * The call can be made from atomic context, so the controller's
220 * implementation of peek_data() must not sleep.
222 * Return: True, if controller has, and is going to push after this,
224 * False, if controller doesn't have any data to be read.
226 bool mbox_client_peek_data(struct mbox_chan *chan)
228 if (chan->mbox->ops->peek_data)
229 return chan->mbox->ops->peek_data(chan);
233 EXPORT_SYMBOL_GPL(mbox_client_peek_data);
236 * mbox_send_message - For client to submit a message to be
237 * sent to the remote.
238 * @chan: Mailbox channel assigned to this client.
239 * @mssg: Client specific message typecasted.
241 * For client to submit data to the controller destined for a remote
242 * processor. If the client had set 'tx_block', the call will return
243 * either when the remote receives the data or when 'tx_tout' millisecs
245 * In non-blocking mode, the requests are buffered by the API and a
246 * non-negative token is returned for each queued request. If the request
247 * is not queued, a negative token is returned. Upon failure or successful
248 * TX, the API calls 'tx_done' from atomic context, from which the client
249 * could submit yet another request.
250 * The pointer to message should be preserved until it is sent
251 * over the chan, i.e, tx_done() is made.
252 * This function could be called from atomic context as it simply
253 * queues the data and returns a token against the request.
255 * Return: Non-negative integer for successful submission (non-blocking mode)
256 * or transmission over chan (blocking mode).
257 * Negative value denotes failure.
259 int mbox_send_message(struct mbox_chan *chan, void *mssg)
263 if (!chan || !chan->cl)
266 t = add_to_rbuf(chan, mssg);
268 dev_err(chan->mbox->dev, "Try increasing MBOX_TX_QUEUE_LEN\n");
274 if (chan->cl->tx_block) {
278 if (!chan->cl->tx_tout) /* wait forever */
279 wait = msecs_to_jiffies(3600000);
281 wait = msecs_to_jiffies(chan->cl->tx_tout);
283 ret = wait_for_completion_timeout(&chan->tx_complete, wait);
292 EXPORT_SYMBOL_GPL(mbox_send_message);
295 * mbox_request_channel - Request a mailbox channel.
296 * @cl: Identity of the client requesting the channel.
297 * @index: Index of mailbox specifier in 'mboxes' property.
299 * The Client specifies its requirements and capabilities while asking for
300 * a mailbox channel. It can't be called from atomic context.
301 * The channel is exclusively allocated and can't be used by another
302 * client before the owner calls mbox_free_channel.
303 * After assignment, any packet received on this channel will be
304 * handed over to the client via the 'rx_callback'.
305 * The framework holds reference to the client, so the mbox_client
306 * structure shouldn't be modified until the mbox_free_channel returns.
308 * Return: Pointer to the channel assigned to the client if successful.
309 * ERR_PTR for request failure.
311 struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
313 struct device *dev = cl->dev;
314 struct mbox_controller *mbox;
315 struct of_phandle_args spec;
316 struct mbox_chan *chan;
320 if (!dev || !dev->of_node) {
321 pr_debug("%s: No owner device node\n", __func__);
322 return ERR_PTR(-ENODEV);
325 mutex_lock(&con_mutex);
327 if (of_parse_phandle_with_args(dev->of_node, "mboxes",
328 "#mbox-cells", index, &spec)) {
329 dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__);
330 mutex_unlock(&con_mutex);
331 return ERR_PTR(-ENODEV);
334 chan = ERR_PTR(-EPROBE_DEFER);
335 list_for_each_entry(mbox, &mbox_cons, node)
336 if (mbox->dev->of_node == spec.np) {
337 chan = mbox->of_xlate(mbox, &spec);
341 of_node_put(spec.np);
344 mutex_unlock(&con_mutex);
348 if (chan->cl || !try_module_get(mbox->dev->driver->owner)) {
349 dev_dbg(dev, "%s: mailbox not free\n", __func__);
350 mutex_unlock(&con_mutex);
351 return ERR_PTR(-EBUSY);
354 spin_lock_irqsave(&chan->lock, flags);
357 chan->active_req = NULL;
359 init_completion(&chan->tx_complete);
361 if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
362 chan->txdone_method = TXDONE_BY_ACK;
364 spin_unlock_irqrestore(&chan->lock, flags);
366 if (chan->mbox->ops->startup) {
367 ret = chan->mbox->ops->startup(chan);
370 dev_err(dev, "Unable to startup the chan (%d)\n", ret);
371 mbox_free_channel(chan);
376 mutex_unlock(&con_mutex);
379 EXPORT_SYMBOL_GPL(mbox_request_channel);
381 struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl,
384 struct device_node *np = cl->dev->of_node;
385 struct property *prop;
386 const char *mbox_name;
390 dev_err(cl->dev, "%s() currently only supports DT\n", __func__);
391 return ERR_PTR(-EINVAL);
394 if (!of_get_property(np, "mbox-names", NULL)) {
396 "%s() requires an \"mbox-names\" property\n", __func__);
397 return ERR_PTR(-EINVAL);
400 of_property_for_each_string(np, "mbox-names", prop, mbox_name) {
401 if (!strncmp(name, mbox_name, strlen(name)))
402 return mbox_request_channel(cl, index);
406 dev_err(cl->dev, "%s() could not locate channel named \"%s\"\n",
408 return ERR_PTR(-EINVAL);
410 EXPORT_SYMBOL_GPL(mbox_request_channel_byname);
413 * mbox_free_channel - The client relinquishes control of a mailbox
414 * channel by this call.
415 * @chan: The mailbox channel to be freed.
417 void mbox_free_channel(struct mbox_chan *chan)
421 if (!chan || !chan->cl)
424 if (chan->mbox->ops->shutdown)
425 chan->mbox->ops->shutdown(chan);
427 /* The queued TX requests are simply aborted, no callbacks are made */
428 spin_lock_irqsave(&chan->lock, flags);
430 chan->active_req = NULL;
431 if (chan->txdone_method == TXDONE_BY_ACK)
432 chan->txdone_method = TXDONE_BY_POLL;
434 module_put(chan->mbox->dev->driver->owner);
435 spin_unlock_irqrestore(&chan->lock, flags);
437 EXPORT_SYMBOL_GPL(mbox_free_channel);
439 static struct mbox_chan *
440 of_mbox_index_xlate(struct mbox_controller *mbox,
441 const struct of_phandle_args *sp)
443 int ind = sp->args[0];
445 if (ind >= mbox->num_chans)
446 return ERR_PTR(-EINVAL);
448 return &mbox->chans[ind];
452 * mbox_controller_register - Register the mailbox controller
453 * @mbox: Pointer to the mailbox controller.
455 * The controller driver registers its communication channels
457 int mbox_controller_register(struct mbox_controller *mbox)
462 if (!mbox || !mbox->dev || !mbox->ops || !mbox->num_chans)
465 if (mbox->txdone_irq)
466 txdone = TXDONE_BY_IRQ;
467 else if (mbox->txdone_poll)
468 txdone = TXDONE_BY_POLL;
469 else /* It has to be ACK then */
470 txdone = TXDONE_BY_ACK;
472 if (txdone == TXDONE_BY_POLL) {
474 if (!mbox->ops->last_tx_done) {
475 dev_err(mbox->dev, "last_tx_done method is absent\n");
479 hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC,
481 mbox->poll_hrt.function = txdone_hrtimer;
482 spin_lock_init(&mbox->poll_hrt_lock);
485 for (i = 0; i < mbox->num_chans; i++) {
486 struct mbox_chan *chan = &mbox->chans[i];
490 chan->txdone_method = txdone;
491 spin_lock_init(&chan->lock);
495 mbox->of_xlate = of_mbox_index_xlate;
497 mutex_lock(&con_mutex);
498 list_add_tail(&mbox->node, &mbox_cons);
499 mutex_unlock(&con_mutex);
503 EXPORT_SYMBOL_GPL(mbox_controller_register);
506 * mbox_controller_unregister - Unregister the mailbox controller
507 * @mbox: Pointer to the mailbox controller.
509 void mbox_controller_unregister(struct mbox_controller *mbox)
516 mutex_lock(&con_mutex);
518 list_del(&mbox->node);
520 for (i = 0; i < mbox->num_chans; i++)
521 mbox_free_channel(&mbox->chans[i]);
523 if (mbox->txdone_poll)
524 hrtimer_cancel(&mbox->poll_hrt);
526 mutex_unlock(&con_mutex);
528 EXPORT_SYMBOL_GPL(mbox_controller_unregister);