Linux 4.1.16
[linux/fpc-iii.git] / drivers / mailbox / mailbox.c
blob19b491d2964f313744513920803e1c327305d7f9
1 /*
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 #include "mailbox.h"
26 static LIST_HEAD(mbox_cons);
27 static DEFINE_MUTEX(con_mutex);
29 static void poll_txdone(unsigned long data);
31 static int add_to_rbuf(struct mbox_chan *chan, void *mssg)
33 int idx;
34 unsigned long flags;
36 spin_lock_irqsave(&chan->lock, flags);
38 /* See if there is any space left */
39 if (chan->msg_count == MBOX_TX_QUEUE_LEN) {
40 spin_unlock_irqrestore(&chan->lock, flags);
41 return -ENOBUFS;
44 idx = chan->msg_free;
45 chan->msg_data[idx] = mssg;
46 chan->msg_count++;
48 if (idx == MBOX_TX_QUEUE_LEN - 1)
49 chan->msg_free = 0;
50 else
51 chan->msg_free++;
53 spin_unlock_irqrestore(&chan->lock, flags);
55 return idx;
58 static void msg_submit(struct mbox_chan *chan)
60 unsigned count, idx;
61 unsigned long flags;
62 void *data;
63 int err = -EBUSY;
65 spin_lock_irqsave(&chan->lock, flags);
67 if (!chan->msg_count || chan->active_req)
68 goto exit;
70 count = chan->msg_count;
71 idx = chan->msg_free;
72 if (idx >= count)
73 idx -= count;
74 else
75 idx += MBOX_TX_QUEUE_LEN - count;
77 data = chan->msg_data[idx];
79 if (chan->cl->tx_prepare)
80 chan->cl->tx_prepare(chan->cl, data);
81 /* Try to submit a message to the MBOX controller */
82 err = chan->mbox->ops->send_data(chan, data);
83 if (!err) {
84 chan->active_req = data;
85 chan->msg_count--;
87 exit:
88 spin_unlock_irqrestore(&chan->lock, flags);
90 if (!err && (chan->txdone_method & TXDONE_BY_POLL))
91 poll_txdone((unsigned long)chan->mbox);
94 static void tx_tick(struct mbox_chan *chan, int r)
96 unsigned long flags;
97 void *mssg;
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 */
105 msg_submit(chan);
107 /* Notify the client */
108 if (mssg && chan->cl->tx_done)
109 chan->cl->tx_done(chan->cl, mssg, r);
111 if (chan->cl->tx_block)
112 complete(&chan->tx_complete);
115 static void poll_txdone(unsigned long data)
117 struct mbox_controller *mbox = (struct mbox_controller *)data;
118 bool txdone, resched = false;
119 int i;
121 for (i = 0; i < mbox->num_chans; i++) {
122 struct mbox_chan *chan = &mbox->chans[i];
124 if (chan->active_req && chan->cl) {
125 txdone = chan->mbox->ops->last_tx_done(chan);
126 if (txdone)
127 tx_tick(chan, 0);
128 else
129 resched = true;
133 if (resched)
134 mod_timer(&mbox->poll, jiffies +
135 msecs_to_jiffies(mbox->txpoll_period));
139 * mbox_chan_received_data - A way for controller driver to push data
140 * received from remote to the upper layer.
141 * @chan: Pointer to the mailbox channel on which RX happened.
142 * @mssg: Client specific message typecasted as void *
144 * After startup and before shutdown any data received on the chan
145 * is passed on to the API via atomic mbox_chan_received_data().
146 * The controller should ACK the RX only after this call returns.
148 void mbox_chan_received_data(struct mbox_chan *chan, void *mssg)
150 /* No buffering the received data */
151 if (chan->cl->rx_callback)
152 chan->cl->rx_callback(chan->cl, mssg);
154 EXPORT_SYMBOL_GPL(mbox_chan_received_data);
157 * mbox_chan_txdone - A way for controller driver to notify the
158 * framework that the last TX has completed.
159 * @chan: Pointer to the mailbox chan on which TX happened.
160 * @r: Status of last TX - OK or ERROR
162 * The controller that has IRQ for TX ACK calls this atomic API
163 * to tick the TX state machine. It works only if txdone_irq
164 * is set by the controller.
166 void mbox_chan_txdone(struct mbox_chan *chan, int r)
168 if (unlikely(!(chan->txdone_method & TXDONE_BY_IRQ))) {
169 dev_err(chan->mbox->dev,
170 "Controller can't run the TX ticker\n");
171 return;
174 tx_tick(chan, r);
176 EXPORT_SYMBOL_GPL(mbox_chan_txdone);
179 * mbox_client_txdone - The way for a client to run the TX state machine.
180 * @chan: Mailbox channel assigned to this client.
181 * @r: Success status of last transmission.
183 * The client/protocol had received some 'ACK' packet and it notifies
184 * the API that the last packet was sent successfully. This only works
185 * if the controller can't sense TX-Done.
187 void mbox_client_txdone(struct mbox_chan *chan, int r)
189 if (unlikely(!(chan->txdone_method & TXDONE_BY_ACK))) {
190 dev_err(chan->mbox->dev, "Client can't run the TX ticker\n");
191 return;
194 tx_tick(chan, r);
196 EXPORT_SYMBOL_GPL(mbox_client_txdone);
199 * mbox_client_peek_data - A way for client driver to pull data
200 * received from remote by the controller.
201 * @chan: Mailbox channel assigned to this client.
203 * A poke to controller driver for any received data.
204 * The data is actually passed onto client via the
205 * mbox_chan_received_data()
206 * The call can be made from atomic context, so the controller's
207 * implementation of peek_data() must not sleep.
209 * Return: True, if controller has, and is going to push after this,
210 * some data.
211 * False, if controller doesn't have any data to be read.
213 bool mbox_client_peek_data(struct mbox_chan *chan)
215 if (chan->mbox->ops->peek_data)
216 return chan->mbox->ops->peek_data(chan);
218 return false;
220 EXPORT_SYMBOL_GPL(mbox_client_peek_data);
223 * mbox_send_message - For client to submit a message to be
224 * sent to the remote.
225 * @chan: Mailbox channel assigned to this client.
226 * @mssg: Client specific message typecasted.
228 * For client to submit data to the controller destined for a remote
229 * processor. If the client had set 'tx_block', the call will return
230 * either when the remote receives the data or when 'tx_tout' millisecs
231 * run out.
232 * In non-blocking mode, the requests are buffered by the API and a
233 * non-negative token is returned for each queued request. If the request
234 * is not queued, a negative token is returned. Upon failure or successful
235 * TX, the API calls 'tx_done' from atomic context, from which the client
236 * could submit yet another request.
237 * The pointer to message should be preserved until it is sent
238 * over the chan, i.e, tx_done() is made.
239 * This function could be called from atomic context as it simply
240 * queues the data and returns a token against the request.
242 * Return: Non-negative integer for successful submission (non-blocking mode)
243 * or transmission over chan (blocking mode).
244 * Negative value denotes failure.
246 int mbox_send_message(struct mbox_chan *chan, void *mssg)
248 int t;
250 if (!chan || !chan->cl)
251 return -EINVAL;
253 t = add_to_rbuf(chan, mssg);
254 if (t < 0) {
255 dev_err(chan->mbox->dev, "Try increasing MBOX_TX_QUEUE_LEN\n");
256 return t;
259 msg_submit(chan);
261 if (chan->cl->tx_block && chan->active_req) {
262 unsigned long wait;
263 int ret;
265 if (!chan->cl->tx_tout) /* wait forever */
266 wait = msecs_to_jiffies(3600000);
267 else
268 wait = msecs_to_jiffies(chan->cl->tx_tout);
270 ret = wait_for_completion_timeout(&chan->tx_complete, wait);
271 if (ret == 0) {
272 t = -EIO;
273 tx_tick(chan, -EIO);
277 return t;
279 EXPORT_SYMBOL_GPL(mbox_send_message);
282 * mbox_request_channel - Request a mailbox channel.
283 * @cl: Identity of the client requesting the channel.
284 * @index: Index of mailbox specifier in 'mboxes' property.
286 * The Client specifies its requirements and capabilities while asking for
287 * a mailbox channel. It can't be called from atomic context.
288 * The channel is exclusively allocated and can't be used by another
289 * client before the owner calls mbox_free_channel.
290 * After assignment, any packet received on this channel will be
291 * handed over to the client via the 'rx_callback'.
292 * The framework holds reference to the client, so the mbox_client
293 * structure shouldn't be modified until the mbox_free_channel returns.
295 * Return: Pointer to the channel assigned to the client if successful.
296 * ERR_PTR for request failure.
298 struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
300 struct device *dev = cl->dev;
301 struct mbox_controller *mbox;
302 struct of_phandle_args spec;
303 struct mbox_chan *chan;
304 unsigned long flags;
305 int ret;
307 if (!dev || !dev->of_node) {
308 pr_debug("%s: No owner device node\n", __func__);
309 return ERR_PTR(-ENODEV);
312 mutex_lock(&con_mutex);
314 if (of_parse_phandle_with_args(dev->of_node, "mboxes",
315 "#mbox-cells", index, &spec)) {
316 dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__);
317 mutex_unlock(&con_mutex);
318 return ERR_PTR(-ENODEV);
321 chan = NULL;
322 list_for_each_entry(mbox, &mbox_cons, node)
323 if (mbox->dev->of_node == spec.np) {
324 chan = mbox->of_xlate(mbox, &spec);
325 break;
328 of_node_put(spec.np);
330 if (!chan || chan->cl || !try_module_get(mbox->dev->driver->owner)) {
331 dev_dbg(dev, "%s: mailbox not free\n", __func__);
332 mutex_unlock(&con_mutex);
333 return ERR_PTR(-EBUSY);
336 spin_lock_irqsave(&chan->lock, flags);
337 chan->msg_free = 0;
338 chan->msg_count = 0;
339 chan->active_req = NULL;
340 chan->cl = cl;
341 init_completion(&chan->tx_complete);
343 if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
344 chan->txdone_method |= TXDONE_BY_ACK;
346 spin_unlock_irqrestore(&chan->lock, flags);
348 ret = chan->mbox->ops->startup(chan);
349 if (ret) {
350 dev_err(dev, "Unable to startup the chan (%d)\n", ret);
351 mbox_free_channel(chan);
352 chan = ERR_PTR(ret);
355 mutex_unlock(&con_mutex);
356 return chan;
358 EXPORT_SYMBOL_GPL(mbox_request_channel);
361 * mbox_free_channel - The client relinquishes control of a mailbox
362 * channel by this call.
363 * @chan: The mailbox channel to be freed.
365 void mbox_free_channel(struct mbox_chan *chan)
367 unsigned long flags;
369 if (!chan || !chan->cl)
370 return;
372 chan->mbox->ops->shutdown(chan);
374 /* The queued TX requests are simply aborted, no callbacks are made */
375 spin_lock_irqsave(&chan->lock, flags);
376 chan->cl = NULL;
377 chan->active_req = NULL;
378 if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
379 chan->txdone_method = TXDONE_BY_POLL;
381 module_put(chan->mbox->dev->driver->owner);
382 spin_unlock_irqrestore(&chan->lock, flags);
384 EXPORT_SYMBOL_GPL(mbox_free_channel);
386 static struct mbox_chan *
387 of_mbox_index_xlate(struct mbox_controller *mbox,
388 const struct of_phandle_args *sp)
390 int ind = sp->args[0];
392 if (ind >= mbox->num_chans)
393 return NULL;
395 return &mbox->chans[ind];
399 * mbox_controller_register - Register the mailbox controller
400 * @mbox: Pointer to the mailbox controller.
402 * The controller driver registers its communication channels
404 int mbox_controller_register(struct mbox_controller *mbox)
406 int i, txdone;
408 /* Sanity check */
409 if (!mbox || !mbox->dev || !mbox->ops || !mbox->num_chans)
410 return -EINVAL;
412 if (mbox->txdone_irq)
413 txdone = TXDONE_BY_IRQ;
414 else if (mbox->txdone_poll)
415 txdone = TXDONE_BY_POLL;
416 else /* It has to be ACK then */
417 txdone = TXDONE_BY_ACK;
419 if (txdone == TXDONE_BY_POLL) {
420 mbox->poll.function = &poll_txdone;
421 mbox->poll.data = (unsigned long)mbox;
422 init_timer(&mbox->poll);
425 for (i = 0; i < mbox->num_chans; i++) {
426 struct mbox_chan *chan = &mbox->chans[i];
428 chan->cl = NULL;
429 chan->mbox = mbox;
430 chan->txdone_method = txdone;
431 spin_lock_init(&chan->lock);
434 if (!mbox->of_xlate)
435 mbox->of_xlate = of_mbox_index_xlate;
437 mutex_lock(&con_mutex);
438 list_add_tail(&mbox->node, &mbox_cons);
439 mutex_unlock(&con_mutex);
441 return 0;
443 EXPORT_SYMBOL_GPL(mbox_controller_register);
446 * mbox_controller_unregister - Unregister the mailbox controller
447 * @mbox: Pointer to the mailbox controller.
449 void mbox_controller_unregister(struct mbox_controller *mbox)
451 int i;
453 if (!mbox)
454 return;
456 mutex_lock(&con_mutex);
458 list_del(&mbox->node);
460 for (i = 0; i < mbox->num_chans; i++)
461 mbox_free_channel(&mbox->chans[i]);
463 if (mbox->txdone_poll)
464 del_timer_sync(&mbox->poll);
466 mutex_unlock(&con_mutex);
468 EXPORT_SYMBOL_GPL(mbox_controller_unregister);