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1/*
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
24#include "mailbox.h"
25
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;
61 int err = -EBUSY;
62
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
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);
81 if (!err) {
82 chan->active_req = data;
83 chan->msg_count--;
84 }
85exit:
86 spin_unlock_irqrestore(&chan->lock, flags);
87
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),
91 HRTIMER_MODE_REL);
92}
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
115static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer)
116{
117 struct mbox_controller *mbox =
118 container_of(hrtimer, struct mbox_controller, poll_hrt);
119 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) {
126 txdone = chan->mbox->ops->last_tx_done(chan);
127 if (txdone)
128 tx_tick(chan, 0);
129 else
130 resched = true;
131 }
132 }
133
134 if (resched) {
135 hrtimer_forward_now(hrtimer, ms_to_ktime(mbox->txpoll_period));
136 return HRTIMER_RESTART;
137 }
138 return HRTIMER_NORESTART;
139}
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
264 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
324 chan = ERR_PTR(-EPROBE_DEFER);
325 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
333 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)) {
339 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
368struct 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__);
378 return ERR_PTR(-EINVAL);
379 }
380
381 if (!of_get_property(np, "mbox-names", NULL)) {
382 dev_err(cl->dev,
383 "%s() requires an \"mbox-names\" property\n", __func__);
384 return ERR_PTR(-EINVAL);
385 }
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
397/**
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)
430 return ERR_PTR(-EINVAL);
431
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) {
457 hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC,
458 HRTIMER_MODE_REL);
459 mbox->poll_hrt.function = txdone_hrtimer;
460 }
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)
501 hrtimer_cancel(&mbox->poll_hrt);
502
503 mutex_unlock(&con_mutex);
504}
505EXPORT_SYMBOL_GPL(mbox_controller_unregister);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Mailbox: Common code for Mailbox controllers and users
4 *
5 * Copyright (C) 2013-2014 Linaro Ltd.
6 * Author: Jassi Brar <jassisinghbrar@gmail.com>
7 */
8
9#include <linux/interrupt.h>
10#include <linux/spinlock.h>
11#include <linux/mutex.h>
12#include <linux/delay.h>
13#include <linux/slab.h>
14#include <linux/err.h>
15#include <linux/module.h>
16#include <linux/device.h>
17#include <linux/bitops.h>
18#include <linux/mailbox_client.h>
19#include <linux/mailbox_controller.h>
20
21#include "mailbox.h"
22
23static LIST_HEAD(mbox_cons);
24static DEFINE_MUTEX(con_mutex);
25
26static int add_to_rbuf(struct mbox_chan *chan, void *mssg)
27{
28 int idx;
29 unsigned long flags;
30
31 spin_lock_irqsave(&chan->lock, flags);
32
33 /* See if there is any space left */
34 if (chan->msg_count == MBOX_TX_QUEUE_LEN) {
35 spin_unlock_irqrestore(&chan->lock, flags);
36 return -ENOBUFS;
37 }
38
39 idx = chan->msg_free;
40 chan->msg_data[idx] = mssg;
41 chan->msg_count++;
42
43 if (idx == MBOX_TX_QUEUE_LEN - 1)
44 chan->msg_free = 0;
45 else
46 chan->msg_free++;
47
48 spin_unlock_irqrestore(&chan->lock, flags);
49
50 return idx;
51}
52
53static void msg_submit(struct mbox_chan *chan)
54{
55 unsigned count, idx;
56 unsigned long flags;
57 void *data;
58 int err = -EBUSY;
59
60 spin_lock_irqsave(&chan->lock, flags);
61
62 if (!chan->msg_count || chan->active_req)
63 goto exit;
64
65 count = chan->msg_count;
66 idx = chan->msg_free;
67 if (idx >= count)
68 idx -= count;
69 else
70 idx += MBOX_TX_QUEUE_LEN - count;
71
72 data = chan->msg_data[idx];
73
74 if (chan->cl->tx_prepare)
75 chan->cl->tx_prepare(chan->cl, data);
76 /* Try to submit a message to the MBOX controller */
77 err = chan->mbox->ops->send_data(chan, data);
78 if (!err) {
79 chan->active_req = data;
80 chan->msg_count--;
81 }
82exit:
83 spin_unlock_irqrestore(&chan->lock, flags);
84
85 /* kick start the timer immediately to avoid delays */
86 if (!err && (chan->txdone_method & TXDONE_BY_POLL)) {
87 /* but only if not already active */
88 if (!hrtimer_active(&chan->mbox->poll_hrt))
89 hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL);
90 }
91}
92
93static void tx_tick(struct mbox_chan *chan, int r)
94{
95 unsigned long flags;
96 void *mssg;
97
98 spin_lock_irqsave(&chan->lock, flags);
99 mssg = chan->active_req;
100 chan->active_req = NULL;
101 spin_unlock_irqrestore(&chan->lock, flags);
102
103 /* Submit next message */
104 msg_submit(chan);
105
106 if (!mssg)
107 return;
108
109 /* Notify the client */
110 if (chan->cl->tx_done)
111 chan->cl->tx_done(chan->cl, mssg, r);
112
113 if (r != -ETIME && chan->cl->tx_block)
114 complete(&chan->tx_complete);
115}
116
117static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer)
118{
119 struct mbox_controller *mbox =
120 container_of(hrtimer, struct mbox_controller, poll_hrt);
121 bool txdone, resched = false;
122 int i;
123
124 for (i = 0; i < mbox->num_chans; i++) {
125 struct mbox_chan *chan = &mbox->chans[i];
126
127 if (chan->active_req && chan->cl) {
128 resched = true;
129 txdone = chan->mbox->ops->last_tx_done(chan);
130 if (txdone)
131 tx_tick(chan, 0);
132 }
133 }
134
135 if (resched) {
136 hrtimer_forward_now(hrtimer, ms_to_ktime(mbox->txpoll_period));
137 return HRTIMER_RESTART;
138 }
139 return HRTIMER_NORESTART;
140}
141
142/**
143 * mbox_chan_received_data - A way for controller driver to push data
144 * received from remote to the upper layer.
145 * @chan: Pointer to the mailbox channel on which RX happened.
146 * @mssg: Client specific message typecasted as void *
147 *
148 * After startup and before shutdown any data received on the chan
149 * is passed on to the API via atomic mbox_chan_received_data().
150 * The controller should ACK the RX only after this call returns.
151 */
152void mbox_chan_received_data(struct mbox_chan *chan, void *mssg)
153{
154 /* No buffering the received data */
155 if (chan->cl->rx_callback)
156 chan->cl->rx_callback(chan->cl, mssg);
157}
158EXPORT_SYMBOL_GPL(mbox_chan_received_data);
159
160/**
161 * mbox_chan_txdone - A way for controller driver to notify the
162 * framework that the last TX has completed.
163 * @chan: Pointer to the mailbox chan on which TX happened.
164 * @r: Status of last TX - OK or ERROR
165 *
166 * The controller that has IRQ for TX ACK calls this atomic API
167 * to tick the TX state machine. It works only if txdone_irq
168 * is set by the controller.
169 */
170void mbox_chan_txdone(struct mbox_chan *chan, int r)
171{
172 if (unlikely(!(chan->txdone_method & TXDONE_BY_IRQ))) {
173 dev_err(chan->mbox->dev,
174 "Controller can't run the TX ticker\n");
175 return;
176 }
177
178 tx_tick(chan, r);
179}
180EXPORT_SYMBOL_GPL(mbox_chan_txdone);
181
182/**
183 * mbox_client_txdone - The way for a client to run the TX state machine.
184 * @chan: Mailbox channel assigned to this client.
185 * @r: Success status of last transmission.
186 *
187 * The client/protocol had received some 'ACK' packet and it notifies
188 * the API that the last packet was sent successfully. This only works
189 * if the controller can't sense TX-Done.
190 */
191void mbox_client_txdone(struct mbox_chan *chan, int r)
192{
193 if (unlikely(!(chan->txdone_method & TXDONE_BY_ACK))) {
194 dev_err(chan->mbox->dev, "Client can't run the TX ticker\n");
195 return;
196 }
197
198 tx_tick(chan, r);
199}
200EXPORT_SYMBOL_GPL(mbox_client_txdone);
201
202/**
203 * mbox_client_peek_data - A way for client driver to pull data
204 * received from remote by the controller.
205 * @chan: Mailbox channel assigned to this client.
206 *
207 * A poke to controller driver for any received data.
208 * The data is actually passed onto client via the
209 * mbox_chan_received_data()
210 * The call can be made from atomic context, so the controller's
211 * implementation of peek_data() must not sleep.
212 *
213 * Return: True, if controller has, and is going to push after this,
214 * some data.
215 * False, if controller doesn't have any data to be read.
216 */
217bool mbox_client_peek_data(struct mbox_chan *chan)
218{
219 if (chan->mbox->ops->peek_data)
220 return chan->mbox->ops->peek_data(chan);
221
222 return false;
223}
224EXPORT_SYMBOL_GPL(mbox_client_peek_data);
225
226/**
227 * mbox_send_message - For client to submit a message to be
228 * sent to the remote.
229 * @chan: Mailbox channel assigned to this client.
230 * @mssg: Client specific message typecasted.
231 *
232 * For client to submit data to the controller destined for a remote
233 * processor. If the client had set 'tx_block', the call will return
234 * either when the remote receives the data or when 'tx_tout' millisecs
235 * run out.
236 * In non-blocking mode, the requests are buffered by the API and a
237 * non-negative token is returned for each queued request. If the request
238 * is not queued, a negative token is returned. Upon failure or successful
239 * TX, the API calls 'tx_done' from atomic context, from which the client
240 * could submit yet another request.
241 * The pointer to message should be preserved until it is sent
242 * over the chan, i.e, tx_done() is made.
243 * This function could be called from atomic context as it simply
244 * queues the data and returns a token against the request.
245 *
246 * Return: Non-negative integer for successful submission (non-blocking mode)
247 * or transmission over chan (blocking mode).
248 * Negative value denotes failure.
249 */
250int mbox_send_message(struct mbox_chan *chan, void *mssg)
251{
252 int t;
253
254 if (!chan || !chan->cl)
255 return -EINVAL;
256
257 t = add_to_rbuf(chan, mssg);
258 if (t < 0) {
259 dev_err(chan->mbox->dev, "Try increasing MBOX_TX_QUEUE_LEN\n");
260 return t;
261 }
262
263 msg_submit(chan);
264
265 if (chan->cl->tx_block) {
266 unsigned long wait;
267 int ret;
268
269 if (!chan->cl->tx_tout) /* wait forever */
270 wait = msecs_to_jiffies(3600000);
271 else
272 wait = msecs_to_jiffies(chan->cl->tx_tout);
273
274 ret = wait_for_completion_timeout(&chan->tx_complete, wait);
275 if (ret == 0) {
276 t = -ETIME;
277 tx_tick(chan, t);
278 }
279 }
280
281 return t;
282}
283EXPORT_SYMBOL_GPL(mbox_send_message);
284
285/**
286 * mbox_flush - flush a mailbox channel
287 * @chan: mailbox channel to flush
288 * @timeout: time, in milliseconds, to allow the flush operation to succeed
289 *
290 * Mailbox controllers that need to work in atomic context can implement the
291 * ->flush() callback to busy loop until a transmission has been completed.
292 * The implementation must call mbox_chan_txdone() upon success. Clients can
293 * call the mbox_flush() function at any time after mbox_send_message() to
294 * flush the transmission. After the function returns success, the mailbox
295 * transmission is guaranteed to have completed.
296 *
297 * Returns: 0 on success or a negative error code on failure.
298 */
299int mbox_flush(struct mbox_chan *chan, unsigned long timeout)
300{
301 int ret;
302
303 if (!chan->mbox->ops->flush)
304 return -ENOTSUPP;
305
306 ret = chan->mbox->ops->flush(chan, timeout);
307 if (ret < 0)
308 tx_tick(chan, ret);
309
310 return ret;
311}
312EXPORT_SYMBOL_GPL(mbox_flush);
313
314/**
315 * mbox_request_channel - Request a mailbox channel.
316 * @cl: Identity of the client requesting the channel.
317 * @index: Index of mailbox specifier in 'mboxes' property.
318 *
319 * The Client specifies its requirements and capabilities while asking for
320 * a mailbox channel. It can't be called from atomic context.
321 * The channel is exclusively allocated and can't be used by another
322 * client before the owner calls mbox_free_channel.
323 * After assignment, any packet received on this channel will be
324 * handed over to the client via the 'rx_callback'.
325 * The framework holds reference to the client, so the mbox_client
326 * structure shouldn't be modified until the mbox_free_channel returns.
327 *
328 * Return: Pointer to the channel assigned to the client if successful.
329 * ERR_PTR for request failure.
330 */
331struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
332{
333 struct device *dev = cl->dev;
334 struct mbox_controller *mbox;
335 struct of_phandle_args spec;
336 struct mbox_chan *chan;
337 unsigned long flags;
338 int ret;
339
340 if (!dev || !dev->of_node) {
341 pr_debug("%s: No owner device node\n", __func__);
342 return ERR_PTR(-ENODEV);
343 }
344
345 mutex_lock(&con_mutex);
346
347 if (of_parse_phandle_with_args(dev->of_node, "mboxes",
348 "#mbox-cells", index, &spec)) {
349 dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__);
350 mutex_unlock(&con_mutex);
351 return ERR_PTR(-ENODEV);
352 }
353
354 chan = ERR_PTR(-EPROBE_DEFER);
355 list_for_each_entry(mbox, &mbox_cons, node)
356 if (mbox->dev->of_node == spec.np) {
357 chan = mbox->of_xlate(mbox, &spec);
358 if (!IS_ERR(chan))
359 break;
360 }
361
362 of_node_put(spec.np);
363
364 if (IS_ERR(chan)) {
365 mutex_unlock(&con_mutex);
366 return chan;
367 }
368
369 if (chan->cl || !try_module_get(mbox->dev->driver->owner)) {
370 dev_dbg(dev, "%s: mailbox not free\n", __func__);
371 mutex_unlock(&con_mutex);
372 return ERR_PTR(-EBUSY);
373 }
374
375 spin_lock_irqsave(&chan->lock, flags);
376 chan->msg_free = 0;
377 chan->msg_count = 0;
378 chan->active_req = NULL;
379 chan->cl = cl;
380 init_completion(&chan->tx_complete);
381
382 if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
383 chan->txdone_method = TXDONE_BY_ACK;
384
385 spin_unlock_irqrestore(&chan->lock, flags);
386
387 if (chan->mbox->ops->startup) {
388 ret = chan->mbox->ops->startup(chan);
389
390 if (ret) {
391 dev_err(dev, "Unable to startup the chan (%d)\n", ret);
392 mbox_free_channel(chan);
393 chan = ERR_PTR(ret);
394 }
395 }
396
397 mutex_unlock(&con_mutex);
398 return chan;
399}
400EXPORT_SYMBOL_GPL(mbox_request_channel);
401
402struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl,
403 const char *name)
404{
405 struct device_node *np = cl->dev->of_node;
406 struct property *prop;
407 const char *mbox_name;
408 int index = 0;
409
410 if (!np) {
411 dev_err(cl->dev, "%s() currently only supports DT\n", __func__);
412 return ERR_PTR(-EINVAL);
413 }
414
415 if (!of_get_property(np, "mbox-names", NULL)) {
416 dev_err(cl->dev,
417 "%s() requires an \"mbox-names\" property\n", __func__);
418 return ERR_PTR(-EINVAL);
419 }
420
421 of_property_for_each_string(np, "mbox-names", prop, mbox_name) {
422 if (!strncmp(name, mbox_name, strlen(name)))
423 return mbox_request_channel(cl, index);
424 index++;
425 }
426
427 dev_err(cl->dev, "%s() could not locate channel named \"%s\"\n",
428 __func__, name);
429 return ERR_PTR(-EINVAL);
430}
431EXPORT_SYMBOL_GPL(mbox_request_channel_byname);
432
433/**
434 * mbox_free_channel - The client relinquishes control of a mailbox
435 * channel by this call.
436 * @chan: The mailbox channel to be freed.
437 */
438void mbox_free_channel(struct mbox_chan *chan)
439{
440 unsigned long flags;
441
442 if (!chan || !chan->cl)
443 return;
444
445 if (chan->mbox->ops->shutdown)
446 chan->mbox->ops->shutdown(chan);
447
448 /* The queued TX requests are simply aborted, no callbacks are made */
449 spin_lock_irqsave(&chan->lock, flags);
450 chan->cl = NULL;
451 chan->active_req = NULL;
452 if (chan->txdone_method == TXDONE_BY_ACK)
453 chan->txdone_method = TXDONE_BY_POLL;
454
455 module_put(chan->mbox->dev->driver->owner);
456 spin_unlock_irqrestore(&chan->lock, flags);
457}
458EXPORT_SYMBOL_GPL(mbox_free_channel);
459
460static struct mbox_chan *
461of_mbox_index_xlate(struct mbox_controller *mbox,
462 const struct of_phandle_args *sp)
463{
464 int ind = sp->args[0];
465
466 if (ind >= mbox->num_chans)
467 return ERR_PTR(-EINVAL);
468
469 return &mbox->chans[ind];
470}
471
472/**
473 * mbox_controller_register - Register the mailbox controller
474 * @mbox: Pointer to the mailbox controller.
475 *
476 * The controller driver registers its communication channels
477 */
478int mbox_controller_register(struct mbox_controller *mbox)
479{
480 int i, txdone;
481
482 /* Sanity check */
483 if (!mbox || !mbox->dev || !mbox->ops || !mbox->num_chans)
484 return -EINVAL;
485
486 if (mbox->txdone_irq)
487 txdone = TXDONE_BY_IRQ;
488 else if (mbox->txdone_poll)
489 txdone = TXDONE_BY_POLL;
490 else /* It has to be ACK then */
491 txdone = TXDONE_BY_ACK;
492
493 if (txdone == TXDONE_BY_POLL) {
494
495 if (!mbox->ops->last_tx_done) {
496 dev_err(mbox->dev, "last_tx_done method is absent\n");
497 return -EINVAL;
498 }
499
500 hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC,
501 HRTIMER_MODE_REL);
502 mbox->poll_hrt.function = txdone_hrtimer;
503 }
504
505 for (i = 0; i < mbox->num_chans; i++) {
506 struct mbox_chan *chan = &mbox->chans[i];
507
508 chan->cl = NULL;
509 chan->mbox = mbox;
510 chan->txdone_method = txdone;
511 spin_lock_init(&chan->lock);
512 }
513
514 if (!mbox->of_xlate)
515 mbox->of_xlate = of_mbox_index_xlate;
516
517 mutex_lock(&con_mutex);
518 list_add_tail(&mbox->node, &mbox_cons);
519 mutex_unlock(&con_mutex);
520
521 return 0;
522}
523EXPORT_SYMBOL_GPL(mbox_controller_register);
524
525/**
526 * mbox_controller_unregister - Unregister the mailbox controller
527 * @mbox: Pointer to the mailbox controller.
528 */
529void mbox_controller_unregister(struct mbox_controller *mbox)
530{
531 int i;
532
533 if (!mbox)
534 return;
535
536 mutex_lock(&con_mutex);
537
538 list_del(&mbox->node);
539
540 for (i = 0; i < mbox->num_chans; i++)
541 mbox_free_channel(&mbox->chans[i]);
542
543 if (mbox->txdone_poll)
544 hrtimer_cancel(&mbox->poll_hrt);
545
546 mutex_unlock(&con_mutex);
547}
548EXPORT_SYMBOL_GPL(mbox_controller_unregister);
549
550static void __devm_mbox_controller_unregister(struct device *dev, void *res)
551{
552 struct mbox_controller **mbox = res;
553
554 mbox_controller_unregister(*mbox);
555}
556
557static int devm_mbox_controller_match(struct device *dev, void *res, void *data)
558{
559 struct mbox_controller **mbox = res;
560
561 if (WARN_ON(!mbox || !*mbox))
562 return 0;
563
564 return *mbox == data;
565}
566
567/**
568 * devm_mbox_controller_register() - managed mbox_controller_register()
569 * @dev: device owning the mailbox controller being registered
570 * @mbox: mailbox controller being registered
571 *
572 * This function adds a device-managed resource that will make sure that the
573 * mailbox controller, which is registered using mbox_controller_register()
574 * as part of this function, will be unregistered along with the rest of
575 * device-managed resources upon driver probe failure or driver removal.
576 *
577 * Returns 0 on success or a negative error code on failure.
578 */
579int devm_mbox_controller_register(struct device *dev,
580 struct mbox_controller *mbox)
581{
582 struct mbox_controller **ptr;
583 int err;
584
585 ptr = devres_alloc(__devm_mbox_controller_unregister, sizeof(*ptr),
586 GFP_KERNEL);
587 if (!ptr)
588 return -ENOMEM;
589
590 err = mbox_controller_register(mbox);
591 if (err < 0) {
592 devres_free(ptr);
593 return err;
594 }
595
596 devres_add(dev, ptr);
597 *ptr = mbox;
598
599 return 0;
600}
601EXPORT_SYMBOL_GPL(devm_mbox_controller_register);
602
603/**
604 * devm_mbox_controller_unregister() - managed mbox_controller_unregister()
605 * @dev: device owning the mailbox controller being unregistered
606 * @mbox: mailbox controller being unregistered
607 *
608 * This function unregisters the mailbox controller and removes the device-
609 * managed resource that was set up to automatically unregister the mailbox
610 * controller on driver probe failure or driver removal. It's typically not
611 * necessary to call this function.
612 */
613void devm_mbox_controller_unregister(struct device *dev, struct mbox_controller *mbox)
614{
615 WARN_ON(devres_release(dev, __devm_mbox_controller_unregister,
616 devm_mbox_controller_match, mbox));
617}
618EXPORT_SYMBOL_GPL(devm_mbox_controller_unregister);