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>
24 #define TXDONE_BY_IRQ BIT(0) /* controller has remote RTR irq */
25 #define TXDONE_BY_POLL BIT(1) /* controller can read status of last TX */
26 #define TXDONE_BY_ACK BIT(2) /* S/W ACK recevied by Client ticks the TX */
28 static LIST_HEAD(mbox_cons);
29 static DEFINE_MUTEX(con_mutex);
31 static void poll_txdone(unsigned long data);
33 static int add_to_rbuf(struct mbox_chan *chan, void *mssg)
38 spin_lock_irqsave(&chan->lock, flags);
40 /* See if there is any space left */
41 if (chan->msg_count == MBOX_TX_QUEUE_LEN) {
42 spin_unlock_irqrestore(&chan->lock, flags);
47 chan->msg_data[idx] = mssg;
50 if (idx == MBOX_TX_QUEUE_LEN - 1)
55 spin_unlock_irqrestore(&chan->lock, flags);
60 static void msg_submit(struct mbox_chan *chan)
67 spin_lock_irqsave(&chan->lock, flags);
69 if (!chan->msg_count || chan->active_req)
72 count = chan->msg_count;
77 idx += MBOX_TX_QUEUE_LEN - count;
79 data = chan->msg_data[idx];
81 if (chan->cl->tx_prepare)
82 chan->cl->tx_prepare(chan->cl, data);
83 /* Try to submit a message to the MBOX controller */
84 err = chan->mbox->ops->send_data(chan, data);
86 chan->active_req = data;
90 spin_unlock_irqrestore(&chan->lock, flags);
92 if (!err && chan->txdone_method == TXDONE_BY_POLL)
93 poll_txdone((unsigned long)chan->mbox);
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 */
109 /* Notify the client */
110 if (mssg && chan->cl->tx_done)
111 chan->cl->tx_done(chan->cl, mssg, r);
113 if (chan->cl->tx_block)
114 complete(&chan->tx_complete);
117 static void poll_txdone(unsigned long data)
119 struct mbox_controller *mbox = (struct mbox_controller *)data;
120 bool txdone, resched = false;
123 for (i = 0; i < mbox->num_chans; i++) {
124 struct mbox_chan *chan = &mbox->chans[i];
126 if (chan->active_req && chan->cl) {
127 txdone = chan->mbox->ops->last_tx_done(chan);
136 mod_timer(&mbox->poll, jiffies +
137 msecs_to_jiffies(mbox->txpoll_period));
141 * mbox_chan_received_data - A way for controller driver to push data
142 * received from remote to the upper layer.
143 * @chan: Pointer to the mailbox channel on which RX happened.
144 * @mssg: Client specific message typecasted as void *
146 * After startup and before shutdown any data received on the chan
147 * is passed on to the API via atomic mbox_chan_received_data().
148 * The controller should ACK the RX only after this call returns.
150 void mbox_chan_received_data(struct mbox_chan *chan, void *mssg)
152 /* No buffering the received data */
153 if (chan->cl->rx_callback)
154 chan->cl->rx_callback(chan->cl, mssg);
156 EXPORT_SYMBOL_GPL(mbox_chan_received_data);
159 * mbox_chan_txdone - A way for controller driver to notify the
160 * framework that the last TX has completed.
161 * @chan: Pointer to the mailbox chan on which TX happened.
162 * @r: Status of last TX - OK or ERROR
164 * The controller that has IRQ for TX ACK calls this atomic API
165 * to tick the TX state machine. It works only if txdone_irq
166 * is set by the controller.
168 void mbox_chan_txdone(struct mbox_chan *chan, int r)
170 if (unlikely(!(chan->txdone_method & TXDONE_BY_IRQ))) {
171 dev_err(chan->mbox->dev,
172 "Controller can't run the TX ticker\n");
178 EXPORT_SYMBOL_GPL(mbox_chan_txdone);
181 * mbox_client_txdone - The way for a client to run the TX state machine.
182 * @chan: Mailbox channel assigned to this client.
183 * @r: Success status of last transmission.
185 * The client/protocol had received some 'ACK' packet and it notifies
186 * the API that the last packet was sent successfully. This only works
187 * if the controller can't sense TX-Done.
189 void mbox_client_txdone(struct mbox_chan *chan, int r)
191 if (unlikely(!(chan->txdone_method & TXDONE_BY_ACK))) {
192 dev_err(chan->mbox->dev, "Client can't run the TX ticker\n");
198 EXPORT_SYMBOL_GPL(mbox_client_txdone);
201 * mbox_client_peek_data - A way for client driver to pull data
202 * received from remote by the controller.
203 * @chan: Mailbox channel assigned to this client.
205 * A poke to controller driver for any received data.
206 * The data is actually passed onto client via the
207 * mbox_chan_received_data()
208 * The call can be made from atomic context, so the controller's
209 * implementation of peek_data() must not sleep.
211 * Return: True, if controller has, and is going to push after this,
213 * False, if controller doesn't have any data to be read.
215 bool mbox_client_peek_data(struct mbox_chan *chan)
217 if (chan->mbox->ops->peek_data)
218 return chan->mbox->ops->peek_data(chan);
222 EXPORT_SYMBOL_GPL(mbox_client_peek_data);
225 * mbox_send_message - For client to submit a message to be
226 * sent to the remote.
227 * @chan: Mailbox channel assigned to this client.
228 * @mssg: Client specific message typecasted.
230 * For client to submit data to the controller destined for a remote
231 * processor. If the client had set 'tx_block', the call will return
232 * either when the remote receives the data or when 'tx_tout' millisecs
234 * In non-blocking mode, the requests are buffered by the API and a
235 * non-negative token is returned for each queued request. If the request
236 * is not queued, a negative token is returned. Upon failure or successful
237 * TX, the API calls 'tx_done' from atomic context, from which the client
238 * could submit yet another request.
239 * The pointer to message should be preserved until it is sent
240 * over the chan, i.e, tx_done() is made.
241 * This function could be called from atomic context as it simply
242 * queues the data and returns a token against the request.
244 * Return: Non-negative integer for successful submission (non-blocking mode)
245 * or transmission over chan (blocking mode).
246 * Negative value denotes failure.
248 int mbox_send_message(struct mbox_chan *chan, void *mssg)
252 if (!chan || !chan->cl)
255 t = add_to_rbuf(chan, mssg);
257 dev_err(chan->mbox->dev, "Try increasing MBOX_TX_QUEUE_LEN\n");
263 if (chan->cl->tx_block && chan->active_req) {
267 if (!chan->cl->tx_tout) /* wait forever */
268 wait = msecs_to_jiffies(3600000);
270 wait = msecs_to_jiffies(chan->cl->tx_tout);
272 ret = wait_for_completion_timeout(&chan->tx_complete, wait);
281 EXPORT_SYMBOL_GPL(mbox_send_message);
284 * mbox_request_channel - Request a mailbox channel.
285 * @cl: Identity of the client requesting the channel.
286 * @index: Index of mailbox specifier in 'mboxes' property.
288 * The Client specifies its requirements and capabilities while asking for
289 * a mailbox channel. It can't be called from atomic context.
290 * The channel is exclusively allocated and can't be used by another
291 * client before the owner calls mbox_free_channel.
292 * After assignment, any packet received on this channel will be
293 * handed over to the client via the 'rx_callback'.
294 * The framework holds reference to the client, so the mbox_client
295 * structure shouldn't be modified until the mbox_free_channel returns.
297 * Return: Pointer to the channel assigned to the client if successful.
298 * ERR_PTR for request failure.
300 struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
302 struct device *dev = cl->dev;
303 struct mbox_controller *mbox;
304 struct of_phandle_args spec;
305 struct mbox_chan *chan;
309 if (!dev || !dev->of_node) {
310 pr_debug("%s: No owner device node\n", __func__);
311 return ERR_PTR(-ENODEV);
314 mutex_lock(&con_mutex);
316 if (of_parse_phandle_with_args(dev->of_node, "mboxes",
317 "#mbox-cells", index, &spec)) {
318 dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__);
319 mutex_unlock(&con_mutex);
320 return ERR_PTR(-ENODEV);
324 list_for_each_entry(mbox, &mbox_cons, node)
325 if (mbox->dev->of_node == spec.np) {
326 chan = mbox->of_xlate(mbox, &spec);
330 of_node_put(spec.np);
332 if (!chan || chan->cl || !try_module_get(mbox->dev->driver->owner)) {
333 dev_dbg(dev, "%s: mailbox not free\n", __func__);
334 mutex_unlock(&con_mutex);
335 return ERR_PTR(-EBUSY);
338 spin_lock_irqsave(&chan->lock, flags);
341 chan->active_req = NULL;
343 init_completion(&chan->tx_complete);
345 if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
346 chan->txdone_method |= TXDONE_BY_ACK;
348 spin_unlock_irqrestore(&chan->lock, flags);
350 ret = chan->mbox->ops->startup(chan);
352 dev_err(dev, "Unable to startup the chan (%d)\n", ret);
353 mbox_free_channel(chan);
357 mutex_unlock(&con_mutex);
360 EXPORT_SYMBOL_GPL(mbox_request_channel);
363 * mbox_free_channel - The client relinquishes control of a mailbox
364 * channel by this call.
365 * @chan: The mailbox channel to be freed.
367 void mbox_free_channel(struct mbox_chan *chan)
371 if (!chan || !chan->cl)
374 chan->mbox->ops->shutdown(chan);
376 /* The queued TX requests are simply aborted, no callbacks are made */
377 spin_lock_irqsave(&chan->lock, flags);
379 chan->active_req = NULL;
380 if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
381 chan->txdone_method = TXDONE_BY_POLL;
383 module_put(chan->mbox->dev->driver->owner);
384 spin_unlock_irqrestore(&chan->lock, flags);
386 EXPORT_SYMBOL_GPL(mbox_free_channel);
388 static struct mbox_chan *
389 of_mbox_index_xlate(struct mbox_controller *mbox,
390 const struct of_phandle_args *sp)
392 int ind = sp->args[0];
394 if (ind >= mbox->num_chans)
397 return &mbox->chans[ind];
401 * mbox_controller_register - Register the mailbox controller
402 * @mbox: Pointer to the mailbox controller.
404 * The controller driver registers its communication channels
406 int mbox_controller_register(struct mbox_controller *mbox)
411 if (!mbox || !mbox->dev || !mbox->ops || !mbox->num_chans)
414 if (mbox->txdone_irq)
415 txdone = TXDONE_BY_IRQ;
416 else if (mbox->txdone_poll)
417 txdone = TXDONE_BY_POLL;
418 else /* It has to be ACK then */
419 txdone = TXDONE_BY_ACK;
421 if (txdone == TXDONE_BY_POLL) {
422 mbox->poll.function = &poll_txdone;
423 mbox->poll.data = (unsigned long)mbox;
424 init_timer(&mbox->poll);
427 for (i = 0; i < mbox->num_chans; i++) {
428 struct mbox_chan *chan = &mbox->chans[i];
432 chan->txdone_method = txdone;
433 spin_lock_init(&chan->lock);
437 mbox->of_xlate = of_mbox_index_xlate;
439 mutex_lock(&con_mutex);
440 list_add_tail(&mbox->node, &mbox_cons);
441 mutex_unlock(&con_mutex);
445 EXPORT_SYMBOL_GPL(mbox_controller_register);
448 * mbox_controller_unregister - Unregister the mailbox controller
449 * @mbox: Pointer to the mailbox controller.
451 void mbox_controller_unregister(struct mbox_controller *mbox)
458 mutex_lock(&con_mutex);
460 list_del(&mbox->node);
462 for (i = 0; i < mbox->num_chans; i++)
463 mbox_free_channel(&mbox->chans[i]);
465 if (mbox->txdone_poll)
466 del_timer_sync(&mbox->poll);
468 mutex_unlock(&con_mutex);
470 EXPORT_SYMBOL_GPL(mbox_controller_unregister);