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 hrtimer_start(&chan->mbox->poll_hrt, ktime_set(0, 0),
94 static void tx_tick(struct mbox_chan *chan, int r)
99 spin_lock_irqsave(&chan->lock, flags);
100 mssg = chan->active_req;
101 chan->active_req = NULL;
102 spin_unlock_irqrestore(&chan->lock, flags);
104 /* Submit next message */
110 /* Notify the client */
111 if (chan->cl->tx_done)
112 chan->cl->tx_done(chan->cl, mssg, r);
114 if (r != -ETIME && chan->cl->tx_block)
115 complete(&chan->tx_complete);
118 static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer)
120 struct mbox_controller *mbox =
121 container_of(hrtimer, struct mbox_controller, poll_hrt);
122 bool txdone, resched = false;
125 for (i = 0; i < mbox->num_chans; i++) {
126 struct mbox_chan *chan = &mbox->chans[i];
128 if (chan->active_req && chan->cl) {
129 txdone = chan->mbox->ops->last_tx_done(chan);
138 hrtimer_forward_now(hrtimer, ms_to_ktime(mbox->txpoll_period));
139 return HRTIMER_RESTART;
141 return HRTIMER_NORESTART;
145 * mbox_chan_received_data - A way for controller driver to push data
146 * received from remote to the upper layer.
147 * @chan: Pointer to the mailbox channel on which RX happened.
148 * @mssg: Client specific message typecasted as void *
150 * After startup and before shutdown any data received on the chan
151 * is passed on to the API via atomic mbox_chan_received_data().
152 * The controller should ACK the RX only after this call returns.
154 void mbox_chan_received_data(struct mbox_chan *chan, void *mssg)
156 /* No buffering the received data */
157 if (chan->cl->rx_callback)
158 chan->cl->rx_callback(chan->cl, mssg);
160 EXPORT_SYMBOL_GPL(mbox_chan_received_data);
163 * mbox_chan_txdone - A way for controller driver to notify the
164 * framework that the last TX has completed.
165 * @chan: Pointer to the mailbox chan on which TX happened.
166 * @r: Status of last TX - OK or ERROR
168 * The controller that has IRQ for TX ACK calls this atomic API
169 * to tick the TX state machine. It works only if txdone_irq
170 * is set by the controller.
172 void mbox_chan_txdone(struct mbox_chan *chan, int r)
174 if (unlikely(!(chan->txdone_method & TXDONE_BY_IRQ))) {
175 dev_err(chan->mbox->dev,
176 "Controller can't run the TX ticker\n");
182 EXPORT_SYMBOL_GPL(mbox_chan_txdone);
185 * mbox_client_txdone - The way for a client to run the TX state machine.
186 * @chan: Mailbox channel assigned to this client.
187 * @r: Success status of last transmission.
189 * The client/protocol had received some 'ACK' packet and it notifies
190 * the API that the last packet was sent successfully. This only works
191 * if the controller can't sense TX-Done.
193 void mbox_client_txdone(struct mbox_chan *chan, int r)
195 if (unlikely(!(chan->txdone_method & TXDONE_BY_ACK))) {
196 dev_err(chan->mbox->dev, "Client can't run the TX ticker\n");
202 EXPORT_SYMBOL_GPL(mbox_client_txdone);
205 * mbox_client_peek_data - A way for client driver to pull data
206 * received from remote by the controller.
207 * @chan: Mailbox channel assigned to this client.
209 * A poke to controller driver for any received data.
210 * The data is actually passed onto client via the
211 * mbox_chan_received_data()
212 * The call can be made from atomic context, so the controller's
213 * implementation of peek_data() must not sleep.
215 * Return: True, if controller has, and is going to push after this,
217 * False, if controller doesn't have any data to be read.
219 bool mbox_client_peek_data(struct mbox_chan *chan)
221 if (chan->mbox->ops->peek_data)
222 return chan->mbox->ops->peek_data(chan);
226 EXPORT_SYMBOL_GPL(mbox_client_peek_data);
229 * mbox_send_message - For client to submit a message to be
230 * sent to the remote.
231 * @chan: Mailbox channel assigned to this client.
232 * @mssg: Client specific message typecasted.
234 * For client to submit data to the controller destined for a remote
235 * processor. If the client had set 'tx_block', the call will return
236 * either when the remote receives the data or when 'tx_tout' millisecs
238 * In non-blocking mode, the requests are buffered by the API and a
239 * non-negative token is returned for each queued request. If the request
240 * is not queued, a negative token is returned. Upon failure or successful
241 * TX, the API calls 'tx_done' from atomic context, from which the client
242 * could submit yet another request.
243 * The pointer to message should be preserved until it is sent
244 * over the chan, i.e, tx_done() is made.
245 * This function could be called from atomic context as it simply
246 * queues the data and returns a token against the request.
248 * Return: Non-negative integer for successful submission (non-blocking mode)
249 * or transmission over chan (blocking mode).
250 * Negative value denotes failure.
252 int mbox_send_message(struct mbox_chan *chan, void *mssg)
256 if (!chan || !chan->cl)
259 t = add_to_rbuf(chan, mssg);
261 dev_err(chan->mbox->dev, "Try increasing MBOX_TX_QUEUE_LEN\n");
267 if (chan->cl->tx_block) {
271 if (!chan->cl->tx_tout) /* wait forever */
272 wait = msecs_to_jiffies(3600000);
274 wait = msecs_to_jiffies(chan->cl->tx_tout);
276 ret = wait_for_completion_timeout(&chan->tx_complete, wait);
285 EXPORT_SYMBOL_GPL(mbox_send_message);
288 * mbox_request_channel - Request a mailbox channel.
289 * @cl: Identity of the client requesting the channel.
290 * @index: Index of mailbox specifier in 'mboxes' property.
292 * The Client specifies its requirements and capabilities while asking for
293 * a mailbox channel. It can't be called from atomic context.
294 * The channel is exclusively allocated and can't be used by another
295 * client before the owner calls mbox_free_channel.
296 * After assignment, any packet received on this channel will be
297 * handed over to the client via the 'rx_callback'.
298 * The framework holds reference to the client, so the mbox_client
299 * structure shouldn't be modified until the mbox_free_channel returns.
301 * Return: Pointer to the channel assigned to the client if successful.
302 * ERR_PTR for request failure.
304 struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
306 struct device *dev = cl->dev;
307 struct mbox_controller *mbox;
308 struct of_phandle_args spec;
309 struct mbox_chan *chan;
313 if (!dev || !dev->of_node) {
314 pr_debug("%s: No owner device node\n", __func__);
315 return ERR_PTR(-ENODEV);
318 mutex_lock(&con_mutex);
320 if (of_parse_phandle_with_args(dev->of_node, "mboxes",
321 "#mbox-cells", index, &spec)) {
322 dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__);
323 mutex_unlock(&con_mutex);
324 return ERR_PTR(-ENODEV);
327 chan = ERR_PTR(-EPROBE_DEFER);
328 list_for_each_entry(mbox, &mbox_cons, node)
329 if (mbox->dev->of_node == spec.np) {
330 chan = mbox->of_xlate(mbox, &spec);
334 of_node_put(spec.np);
337 mutex_unlock(&con_mutex);
341 if (chan->cl || !try_module_get(mbox->dev->driver->owner)) {
342 dev_dbg(dev, "%s: mailbox not free\n", __func__);
343 mutex_unlock(&con_mutex);
344 return ERR_PTR(-EBUSY);
347 spin_lock_irqsave(&chan->lock, flags);
350 chan->active_req = NULL;
352 init_completion(&chan->tx_complete);
354 if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
355 chan->txdone_method |= TXDONE_BY_ACK;
357 spin_unlock_irqrestore(&chan->lock, flags);
359 ret = chan->mbox->ops->startup(chan);
361 dev_err(dev, "Unable to startup the chan (%d)\n", ret);
362 mbox_free_channel(chan);
366 mutex_unlock(&con_mutex);
369 EXPORT_SYMBOL_GPL(mbox_request_channel);
371 struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl,
374 struct device_node *np = cl->dev->of_node;
375 struct property *prop;
376 const char *mbox_name;
380 dev_err(cl->dev, "%s() currently only supports DT\n", __func__);
381 return ERR_PTR(-ENOSYS);
384 if (!of_get_property(np, "mbox-names", NULL)) {
386 "%s() requires an \"mbox-names\" property\n", __func__);
387 return ERR_PTR(-ENOSYS);
390 of_property_for_each_string(np, "mbox-names", prop, mbox_name) {
391 if (!strncmp(name, mbox_name, strlen(name)))
392 return mbox_request_channel(cl, index);
396 dev_err(cl->dev, "%s() could not locate channel named \"%s\"\n",
398 return ERR_PTR(-EINVAL);
400 EXPORT_SYMBOL_GPL(mbox_request_channel_byname);
403 * mbox_free_channel - The client relinquishes control of a mailbox
404 * channel by this call.
405 * @chan: The mailbox channel to be freed.
407 void mbox_free_channel(struct mbox_chan *chan)
411 if (!chan || !chan->cl)
414 chan->mbox->ops->shutdown(chan);
416 /* The queued TX requests are simply aborted, no callbacks are made */
417 spin_lock_irqsave(&chan->lock, flags);
419 chan->active_req = NULL;
420 if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
421 chan->txdone_method = TXDONE_BY_POLL;
423 module_put(chan->mbox->dev->driver->owner);
424 spin_unlock_irqrestore(&chan->lock, flags);
426 EXPORT_SYMBOL_GPL(mbox_free_channel);
428 static struct mbox_chan *
429 of_mbox_index_xlate(struct mbox_controller *mbox,
430 const struct of_phandle_args *sp)
432 int ind = sp->args[0];
434 if (ind >= mbox->num_chans)
435 return ERR_PTR(-EINVAL);
437 return &mbox->chans[ind];
441 * mbox_controller_register - Register the mailbox controller
442 * @mbox: Pointer to the mailbox controller.
444 * The controller driver registers its communication channels
446 int mbox_controller_register(struct mbox_controller *mbox)
451 if (!mbox || !mbox->dev || !mbox->ops || !mbox->num_chans)
454 if (mbox->txdone_irq)
455 txdone = TXDONE_BY_IRQ;
456 else if (mbox->txdone_poll)
457 txdone = TXDONE_BY_POLL;
458 else /* It has to be ACK then */
459 txdone = TXDONE_BY_ACK;
461 if (txdone == TXDONE_BY_POLL) {
462 hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC,
464 mbox->poll_hrt.function = txdone_hrtimer;
467 for (i = 0; i < mbox->num_chans; i++) {
468 struct mbox_chan *chan = &mbox->chans[i];
472 chan->txdone_method = txdone;
473 spin_lock_init(&chan->lock);
477 mbox->of_xlate = of_mbox_index_xlate;
479 mutex_lock(&con_mutex);
480 list_add_tail(&mbox->node, &mbox_cons);
481 mutex_unlock(&con_mutex);
485 EXPORT_SYMBOL_GPL(mbox_controller_register);
488 * mbox_controller_unregister - Unregister the mailbox controller
489 * @mbox: Pointer to the mailbox controller.
491 void mbox_controller_unregister(struct mbox_controller *mbox)
498 mutex_lock(&con_mutex);
500 list_del(&mbox->node);
502 for (i = 0; i < mbox->num_chans; i++)
503 mbox_free_channel(&mbox->chans[i]);
505 if (mbox->txdone_poll)
506 hrtimer_cancel(&mbox->poll_hrt);
508 mutex_unlock(&con_mutex);
510 EXPORT_SYMBOL_GPL(mbox_controller_unregister);