xref: /linux/drivers/mailbox/omap-mailbox.c (revision a7cc308da5f78eee8d94bf666c026671a180d7e5)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * OMAP mailbox driver
4  *
5  * Copyright (C) 2006-2009 Nokia Corporation. All rights reserved.
6  * Copyright (C) 2013-2021 Texas Instruments Incorporated - https://www.ti.com
7  *
8  * Contact: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
9  *          Suman Anna <s-anna@ti.com>
10  */
11 
12 #include <linux/interrupt.h>
13 #include <linux/spinlock.h>
14 #include <linux/mutex.h>
15 #include <linux/slab.h>
16 #include <linux/kfifo.h>
17 #include <linux/err.h>
18 #include <linux/io.h>
19 #include <linux/module.h>
20 #include <linux/of.h>
21 #include <linux/platform_device.h>
22 #include <linux/pm_runtime.h>
23 #include <linux/mailbox_controller.h>
24 
25 #define MAILBOX_REVISION		0x000
26 #define MAILBOX_MESSAGE(m)		(0x040 + 4 * (m))
27 #define MAILBOX_FIFOSTATUS(m)		(0x080 + 4 * (m))
28 #define MAILBOX_MSGSTATUS(m)		(0x0c0 + 4 * (m))
29 
30 #define OMAP2_MAILBOX_IRQSTATUS(u)	(0x100 + 8 * (u))
31 #define OMAP2_MAILBOX_IRQENABLE(u)	(0x104 + 8 * (u))
32 
33 #define OMAP4_MAILBOX_IRQSTATUS(u)	(0x104 + 0x10 * (u))
34 #define OMAP4_MAILBOX_IRQENABLE(u)	(0x108 + 0x10 * (u))
35 #define OMAP4_MAILBOX_IRQENABLE_CLR(u)	(0x10c + 0x10 * (u))
36 
37 #define MAILBOX_IRQSTATUS(type, u)	(type ? OMAP4_MAILBOX_IRQSTATUS(u) : \
38 						OMAP2_MAILBOX_IRQSTATUS(u))
39 #define MAILBOX_IRQENABLE(type, u)	(type ? OMAP4_MAILBOX_IRQENABLE(u) : \
40 						OMAP2_MAILBOX_IRQENABLE(u))
41 #define MAILBOX_IRQDISABLE(type, u)	(type ? OMAP4_MAILBOX_IRQENABLE_CLR(u) \
42 						: OMAP2_MAILBOX_IRQENABLE(u))
43 
44 #define MAILBOX_IRQ_NEWMSG(m)		(1 << (2 * (m)))
45 #define MAILBOX_IRQ_NOTFULL(m)		(1 << (2 * (m) + 1))
46 
47 /* Interrupt register configuration types */
48 #define MBOX_INTR_CFG_TYPE1		0
49 #define MBOX_INTR_CFG_TYPE2		1
50 
51 typedef enum {
52 	IRQ_TX = 1,
53 	IRQ_RX = 2,
54 } omap_mbox_irq_t;
55 
56 struct omap_mbox_fifo {
57 	unsigned long msg;
58 	unsigned long fifo_stat;
59 	unsigned long msg_stat;
60 	unsigned long irqenable;
61 	unsigned long irqstatus;
62 	unsigned long irqdisable;
63 	u32 intr_bit;
64 };
65 
66 struct omap_mbox_match_data {
67 	u32 intr_type;
68 	bool is_exclusive;
69 };
70 
71 struct omap_mbox_device {
72 	struct device *dev;
73 	struct mutex cfg_lock;
74 	void __iomem *mbox_base;
75 	u32 *irq_ctx;
76 	u32 num_users;
77 	u32 num_fifos;
78 	u32 intr_type;
79 	const struct omap_mbox_match_data *mbox_data;
80 };
81 
82 struct omap_mbox {
83 	const char		*name;
84 	int			irq;
85 	struct omap_mbox_device *parent;
86 	struct omap_mbox_fifo	tx_fifo;
87 	struct omap_mbox_fifo	rx_fifo;
88 	u32			intr_type;
89 	struct mbox_chan	*chan;
90 	bool			send_no_irq;
91 };
92 
93 static inline
mbox_read_reg(struct omap_mbox_device * mdev,size_t ofs)94 unsigned int mbox_read_reg(struct omap_mbox_device *mdev, size_t ofs)
95 {
96 	return __raw_readl(mdev->mbox_base + ofs);
97 }
98 
99 static inline
mbox_write_reg(struct omap_mbox_device * mdev,u32 val,size_t ofs)100 void mbox_write_reg(struct omap_mbox_device *mdev, u32 val, size_t ofs)
101 {
102 	__raw_writel(val, mdev->mbox_base + ofs);
103 }
104 
105 /* Mailbox FIFO handle functions */
mbox_fifo_read(struct omap_mbox * mbox)106 static u32 mbox_fifo_read(struct omap_mbox *mbox)
107 {
108 	struct omap_mbox_fifo *fifo = &mbox->rx_fifo;
109 
110 	return mbox_read_reg(mbox->parent, fifo->msg);
111 }
112 
mbox_fifo_write(struct omap_mbox * mbox,u32 msg)113 static void mbox_fifo_write(struct omap_mbox *mbox, u32 msg)
114 {
115 	struct omap_mbox_fifo *fifo = &mbox->tx_fifo;
116 
117 	mbox_write_reg(mbox->parent, msg, fifo->msg);
118 }
119 
mbox_fifo_empty(struct omap_mbox * mbox)120 static int mbox_fifo_empty(struct omap_mbox *mbox)
121 {
122 	struct omap_mbox_fifo *fifo = &mbox->rx_fifo;
123 
124 	return (mbox_read_reg(mbox->parent, fifo->msg_stat) == 0);
125 }
126 
mbox_fifo_full(struct omap_mbox * mbox)127 static int mbox_fifo_full(struct omap_mbox *mbox)
128 {
129 	struct omap_mbox_fifo *fifo = &mbox->tx_fifo;
130 
131 	return mbox_read_reg(mbox->parent, fifo->fifo_stat);
132 }
133 
134 /* Mailbox IRQ handle functions */
ack_mbox_irq(struct omap_mbox * mbox,omap_mbox_irq_t irq)135 static void ack_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
136 {
137 	struct omap_mbox_fifo *fifo = (irq == IRQ_TX) ?
138 				&mbox->tx_fifo : &mbox->rx_fifo;
139 	u32 bit = fifo->intr_bit;
140 	u32 irqstatus = fifo->irqstatus;
141 
142 	mbox_write_reg(mbox->parent, bit, irqstatus);
143 
144 	/* Flush posted write for irq status to avoid spurious interrupts */
145 	mbox_read_reg(mbox->parent, irqstatus);
146 }
147 
is_mbox_irq(struct omap_mbox * mbox,omap_mbox_irq_t irq)148 static int is_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
149 {
150 	struct omap_mbox_fifo *fifo = (irq == IRQ_TX) ?
151 				&mbox->tx_fifo : &mbox->rx_fifo;
152 	u32 bit = fifo->intr_bit;
153 	u32 irqenable = fifo->irqenable;
154 	u32 irqstatus = fifo->irqstatus;
155 
156 	u32 enable = mbox_read_reg(mbox->parent, irqenable);
157 	u32 status = mbox_read_reg(mbox->parent, irqstatus);
158 
159 	return (int)(enable & status & bit);
160 }
161 
omap_mbox_enable_irq(struct omap_mbox * mbox,omap_mbox_irq_t irq)162 static void omap_mbox_enable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
163 {
164 	u32 l;
165 	struct omap_mbox_fifo *fifo = (irq == IRQ_TX) ?
166 				&mbox->tx_fifo : &mbox->rx_fifo;
167 	u32 bit = fifo->intr_bit;
168 	u32 irqenable = fifo->irqenable;
169 
170 	l = mbox_read_reg(mbox->parent, irqenable);
171 	l |= bit;
172 	mbox_write_reg(mbox->parent, l, irqenable);
173 }
174 
omap_mbox_disable_irq(struct omap_mbox * mbox,omap_mbox_irq_t irq)175 static void omap_mbox_disable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
176 {
177 	struct omap_mbox_fifo *fifo = (irq == IRQ_TX) ?
178 				&mbox->tx_fifo : &mbox->rx_fifo;
179 	u32 bit = fifo->intr_bit;
180 	u32 irqdisable = fifo->irqdisable;
181 
182 	/*
183 	 * Read and update the interrupt configuration register for pre-OMAP4.
184 	 * OMAP4 and later SoCs have a dedicated interrupt disabling register.
185 	 */
186 	if (!mbox->intr_type)
187 		bit = mbox_read_reg(mbox->parent, irqdisable) & ~bit;
188 
189 	mbox_write_reg(mbox->parent, bit, irqdisable);
190 }
191 
192 /*
193  * Mailbox interrupt handler
194  */
__mbox_tx_interrupt(struct omap_mbox * mbox)195 static void __mbox_tx_interrupt(struct omap_mbox *mbox)
196 {
197 	omap_mbox_disable_irq(mbox, IRQ_TX);
198 	ack_mbox_irq(mbox, IRQ_TX);
199 	mbox_chan_txdone(mbox->chan, 0);
200 }
201 
__mbox_rx_interrupt(struct omap_mbox * mbox)202 static void __mbox_rx_interrupt(struct omap_mbox *mbox)
203 {
204 	u32 msg;
205 
206 	while (!mbox_fifo_empty(mbox)) {
207 		msg = mbox_fifo_read(mbox);
208 		mbox_chan_received_data(mbox->chan, (void *)(uintptr_t)msg);
209 	}
210 
211 	/* clear IRQ source. */
212 	ack_mbox_irq(mbox, IRQ_RX);
213 }
214 
mbox_interrupt(int irq,void * p)215 static irqreturn_t mbox_interrupt(int irq, void *p)
216 {
217 	struct omap_mbox *mbox = p;
218 
219 	if (is_mbox_irq(mbox, IRQ_TX))
220 		__mbox_tx_interrupt(mbox);
221 
222 	if (is_mbox_irq(mbox, IRQ_RX))
223 		__mbox_rx_interrupt(mbox);
224 
225 	return IRQ_HANDLED;
226 }
227 
omap_mbox_startup(struct omap_mbox * mbox)228 static int omap_mbox_startup(struct omap_mbox *mbox)
229 {
230 	int ret = 0;
231 
232 	ret = request_threaded_irq(mbox->irq, NULL, mbox_interrupt,
233 				   IRQF_SHARED | IRQF_ONESHOT, mbox->name,
234 				   mbox);
235 	if (unlikely(ret)) {
236 		pr_err("failed to register mailbox interrupt:%d\n", ret);
237 		return ret;
238 	}
239 
240 	if (mbox->send_no_irq)
241 		mbox->chan->txdone_method = MBOX_TXDONE_BY_ACK;
242 
243 	omap_mbox_enable_irq(mbox, IRQ_RX);
244 
245 	return 0;
246 }
247 
omap_mbox_fini(struct omap_mbox * mbox)248 static void omap_mbox_fini(struct omap_mbox *mbox)
249 {
250 	omap_mbox_disable_irq(mbox, IRQ_RX);
251 	free_irq(mbox->irq, mbox);
252 }
253 
omap_mbox_chan_startup(struct mbox_chan * chan)254 static int omap_mbox_chan_startup(struct mbox_chan *chan)
255 {
256 	struct omap_mbox *mbox = chan->con_priv;
257 	struct omap_mbox_device *mdev = mbox->parent;
258 	int ret = 0;
259 
260 	mutex_lock(&mdev->cfg_lock);
261 	pm_runtime_get_sync(mdev->dev);
262 	ret = omap_mbox_startup(mbox);
263 	if (ret)
264 		pm_runtime_put_sync(mdev->dev);
265 	mutex_unlock(&mdev->cfg_lock);
266 	return ret;
267 }
268 
omap_mbox_chan_shutdown(struct mbox_chan * chan)269 static void omap_mbox_chan_shutdown(struct mbox_chan *chan)
270 {
271 	struct omap_mbox *mbox = chan->con_priv;
272 	struct omap_mbox_device *mdev = mbox->parent;
273 
274 	mutex_lock(&mdev->cfg_lock);
275 	omap_mbox_fini(mbox);
276 	pm_runtime_put_sync(mdev->dev);
277 	mutex_unlock(&mdev->cfg_lock);
278 }
279 
omap_mbox_chan_send_noirq(struct omap_mbox * mbox,u32 msg)280 static int omap_mbox_chan_send_noirq(struct omap_mbox *mbox, u32 msg)
281 {
282 	if (mbox_fifo_full(mbox))
283 		return -EBUSY;
284 
285 	omap_mbox_enable_irq(mbox, IRQ_RX);
286 	mbox_fifo_write(mbox, msg);
287 	omap_mbox_disable_irq(mbox, IRQ_RX);
288 
289 	/* we must read and ack the interrupt directly from here */
290 	mbox_fifo_read(mbox);
291 	ack_mbox_irq(mbox, IRQ_RX);
292 
293 	return 0;
294 }
295 
omap_mbox_chan_send(struct omap_mbox * mbox,u32 msg)296 static int omap_mbox_chan_send(struct omap_mbox *mbox, u32 msg)
297 {
298 	if (mbox_fifo_full(mbox)) {
299 		/* always enable the interrupt */
300 		omap_mbox_enable_irq(mbox, IRQ_TX);
301 		return -EBUSY;
302 	}
303 
304 	mbox_fifo_write(mbox, msg);
305 
306 	/* always enable the interrupt */
307 	omap_mbox_enable_irq(mbox, IRQ_TX);
308 	return 0;
309 }
310 
omap_mbox_chan_send_data(struct mbox_chan * chan,void * data)311 static int omap_mbox_chan_send_data(struct mbox_chan *chan, void *data)
312 {
313 	struct omap_mbox *mbox = chan->con_priv;
314 	int ret;
315 	u32 msg = (u32)(uintptr_t)(data);
316 
317 	if (!mbox)
318 		return -EINVAL;
319 
320 	if (mbox->send_no_irq)
321 		ret = omap_mbox_chan_send_noirq(mbox, msg);
322 	else
323 		ret = omap_mbox_chan_send(mbox, msg);
324 
325 	return ret;
326 }
327 
328 static const struct mbox_chan_ops omap_mbox_chan_ops = {
329 	.startup        = omap_mbox_chan_startup,
330 	.send_data      = omap_mbox_chan_send_data,
331 	.shutdown       = omap_mbox_chan_shutdown,
332 };
333 
334 #ifdef CONFIG_PM_SLEEP
omap_mbox_suspend(struct device * dev)335 static int omap_mbox_suspend(struct device *dev)
336 {
337 	struct omap_mbox_device *mdev = dev_get_drvdata(dev);
338 	u32 usr, fifo, reg;
339 
340 	if (pm_runtime_status_suspended(dev))
341 		return 0;
342 
343 	if (mdev->mbox_data->is_exclusive) {
344 		for (fifo = 0; fifo < mdev->num_fifos; fifo++) {
345 			if (mbox_read_reg(mdev, MAILBOX_MSGSTATUS(fifo))) {
346 				dev_err(mdev->dev, "fifo %d has unexpected unread messages\n",
347 					fifo);
348 				return -EBUSY;
349 			}
350 		}
351 	}
352 
353 	for (usr = 0; usr < mdev->num_users; usr++) {
354 		reg = MAILBOX_IRQENABLE(mdev->intr_type, usr);
355 		mdev->irq_ctx[usr] = mbox_read_reg(mdev, reg);
356 	}
357 
358 	return 0;
359 }
360 
omap_mbox_resume(struct device * dev)361 static int omap_mbox_resume(struct device *dev)
362 {
363 	struct omap_mbox_device *mdev = dev_get_drvdata(dev);
364 	u32 usr, reg;
365 
366 	if (pm_runtime_status_suspended(dev))
367 		return 0;
368 
369 	for (usr = 0; usr < mdev->num_users; usr++) {
370 		reg = MAILBOX_IRQENABLE(mdev->intr_type, usr);
371 		mbox_write_reg(mdev, mdev->irq_ctx[usr], reg);
372 	}
373 
374 	return 0;
375 }
376 #endif
377 
378 static const struct dev_pm_ops omap_mbox_pm_ops = {
379 	SET_SYSTEM_SLEEP_PM_OPS(omap_mbox_suspend, omap_mbox_resume)
380 };
381 
382 static const struct omap_mbox_match_data omap2_data = { MBOX_INTR_CFG_TYPE1, true };
383 static const struct omap_mbox_match_data omap4_data = { MBOX_INTR_CFG_TYPE2, true };
384 static const struct omap_mbox_match_data am654_data = { MBOX_INTR_CFG_TYPE2, false };
385 
386 static const struct of_device_id omap_mailbox_of_match[] = {
387 	{
388 		.compatible	= "ti,omap2-mailbox",
389 		.data		= &omap2_data,
390 	},
391 	{
392 		.compatible	= "ti,omap3-mailbox",
393 		.data		= &omap2_data,
394 	},
395 	{
396 		.compatible	= "ti,omap4-mailbox",
397 		.data		= &omap4_data,
398 	},
399 	{
400 		.compatible	= "ti,am654-mailbox",
401 		.data		= &am654_data,
402 	},
403 	{
404 		.compatible	= "ti,am64-mailbox",
405 		.data		= &am654_data,
406 	},
407 	{
408 		/* end */
409 	},
410 };
411 MODULE_DEVICE_TABLE(of, omap_mailbox_of_match);
412 
omap_mbox_of_xlate(struct mbox_controller * controller,const struct of_phandle_args * sp)413 static struct mbox_chan *omap_mbox_of_xlate(struct mbox_controller *controller,
414 					    const struct of_phandle_args *sp)
415 {
416 	phandle phandle = sp->args[0];
417 	struct device_node *node;
418 	struct omap_mbox_device *mdev;
419 	struct omap_mbox *mbox;
420 	int i;
421 
422 	mdev = dev_get_drvdata(controller->dev);
423 	if (WARN_ON(!mdev))
424 		return ERR_PTR(-EINVAL);
425 
426 	node = of_find_node_by_phandle(phandle);
427 	if (!node) {
428 		pr_err("%s: could not find node phandle 0x%x\n",
429 		       __func__, phandle);
430 		return ERR_PTR(-ENODEV);
431 	}
432 
433 	for (i = 0; i < controller->num_chans; i++) {
434 		mbox = controller->chans[i].con_priv;
435 		if (!strcmp(mbox->name, node->name)) {
436 			of_node_put(node);
437 			return &controller->chans[i];
438 		}
439 	}
440 
441 	of_node_put(node);
442 	return ERR_PTR(-ENOENT);
443 }
444 
omap_mbox_probe(struct platform_device * pdev)445 static int omap_mbox_probe(struct platform_device *pdev)
446 {
447 	int ret;
448 	struct mbox_chan *chnls;
449 	struct omap_mbox *mbox;
450 	struct omap_mbox_device *mdev;
451 	struct omap_mbox_fifo *fifo;
452 	struct device_node *node = pdev->dev.of_node;
453 	struct device_node *child;
454 	struct mbox_controller *controller;
455 	u32 intr_type, info_count;
456 	u32 num_users, num_fifos;
457 	u32 tmp[3];
458 	u32 l;
459 	int i;
460 
461 	if (!node) {
462 		pr_err("%s: only DT-based devices are supported\n", __func__);
463 		return -ENODEV;
464 	}
465 
466 	if (of_property_read_u32(node, "ti,mbox-num-users", &num_users))
467 		return -ENODEV;
468 
469 	if (of_property_read_u32(node, "ti,mbox-num-fifos", &num_fifos))
470 		return -ENODEV;
471 
472 	info_count = of_get_available_child_count(node);
473 	if (!info_count) {
474 		dev_err(&pdev->dev, "no available mbox devices found\n");
475 		return -ENODEV;
476 	}
477 
478 	mdev = devm_kzalloc(&pdev->dev, sizeof(*mdev), GFP_KERNEL);
479 	if (!mdev)
480 		return -ENOMEM;
481 
482 	mdev->mbox_data = device_get_match_data(&pdev->dev);
483 	if (!mdev->mbox_data)
484 		return -ENODEV;
485 
486 	intr_type = mdev->mbox_data->intr_type;
487 
488 	mdev->mbox_base = devm_platform_ioremap_resource(pdev, 0);
489 	if (IS_ERR(mdev->mbox_base))
490 		return PTR_ERR(mdev->mbox_base);
491 
492 	mdev->irq_ctx = devm_kcalloc(&pdev->dev, num_users, sizeof(u32),
493 				     GFP_KERNEL);
494 	if (!mdev->irq_ctx)
495 		return -ENOMEM;
496 
497 	chnls = devm_kcalloc(&pdev->dev, info_count + 1, sizeof(*chnls),
498 			     GFP_KERNEL);
499 	if (!chnls)
500 		return -ENOMEM;
501 
502 	child = NULL;
503 	for (i = 0; i < info_count; i++) {
504 		int tx_id, tx_irq, tx_usr;
505 		int rx_id,         rx_usr;
506 
507 		mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL);
508 		if (!mbox)
509 			return -ENOMEM;
510 
511 		child = of_get_next_available_child(node, child);
512 		ret = of_property_read_u32_array(child, "ti,mbox-tx", tmp,
513 						 ARRAY_SIZE(tmp));
514 		if (ret)
515 			return ret;
516 		tx_id = tmp[0];
517 		tx_irq = tmp[1];
518 		tx_usr = tmp[2];
519 
520 		ret = of_property_read_u32_array(child, "ti,mbox-rx", tmp,
521 						 ARRAY_SIZE(tmp));
522 		if (ret)
523 			return ret;
524 		rx_id = tmp[0];
525 		/* rx_irq = tmp[1]; */
526 		rx_usr = tmp[2];
527 
528 		if (tx_id >= num_fifos || rx_id >= num_fifos ||
529 		    tx_usr >= num_users || rx_usr >= num_users)
530 			return -EINVAL;
531 
532 		fifo = &mbox->tx_fifo;
533 		fifo->msg = MAILBOX_MESSAGE(tx_id);
534 		fifo->fifo_stat = MAILBOX_FIFOSTATUS(tx_id);
535 		fifo->intr_bit = MAILBOX_IRQ_NOTFULL(tx_id);
536 		fifo->irqenable = MAILBOX_IRQENABLE(intr_type, tx_usr);
537 		fifo->irqstatus = MAILBOX_IRQSTATUS(intr_type, tx_usr);
538 		fifo->irqdisable = MAILBOX_IRQDISABLE(intr_type, tx_usr);
539 
540 		fifo = &mbox->rx_fifo;
541 		fifo->msg = MAILBOX_MESSAGE(rx_id);
542 		fifo->msg_stat =  MAILBOX_MSGSTATUS(rx_id);
543 		fifo->intr_bit = MAILBOX_IRQ_NEWMSG(rx_id);
544 		fifo->irqenable = MAILBOX_IRQENABLE(intr_type, rx_usr);
545 		fifo->irqstatus = MAILBOX_IRQSTATUS(intr_type, rx_usr);
546 		fifo->irqdisable = MAILBOX_IRQDISABLE(intr_type, rx_usr);
547 
548 		mbox->send_no_irq = of_property_read_bool(child, "ti,mbox-send-noirq");
549 		mbox->intr_type = intr_type;
550 
551 		mbox->parent = mdev;
552 		mbox->name = child->name;
553 		mbox->irq = platform_get_irq(pdev, tx_irq);
554 		if (mbox->irq < 0)
555 			return mbox->irq;
556 		mbox->chan = &chnls[i];
557 		chnls[i].con_priv = mbox;
558 	}
559 
560 	mutex_init(&mdev->cfg_lock);
561 	mdev->dev = &pdev->dev;
562 	mdev->num_users = num_users;
563 	mdev->num_fifos = num_fifos;
564 	mdev->intr_type = intr_type;
565 
566 	controller = devm_kzalloc(&pdev->dev, sizeof(*controller), GFP_KERNEL);
567 	if (!controller)
568 		return -ENOMEM;
569 	/*
570 	 * OMAP/K3 Mailbox IP does not have a Tx-Done IRQ, but rather a Tx-Ready
571 	 * IRQ and is needed to run the Tx state machine
572 	 */
573 	controller->txdone_irq = true;
574 	controller->dev = mdev->dev;
575 	controller->ops = &omap_mbox_chan_ops;
576 	controller->chans = chnls;
577 	controller->num_chans = info_count;
578 	controller->of_xlate = omap_mbox_of_xlate;
579 	ret = devm_mbox_controller_register(mdev->dev, controller);
580 	if (ret)
581 		return ret;
582 
583 	platform_set_drvdata(pdev, mdev);
584 	devm_pm_runtime_enable(mdev->dev);
585 
586 	ret = pm_runtime_resume_and_get(mdev->dev);
587 	if (ret < 0)
588 		return ret;
589 
590 	/*
591 	 * just print the raw revision register, the format is not
592 	 * uniform across all SoCs
593 	 */
594 	l = mbox_read_reg(mdev, MAILBOX_REVISION);
595 	dev_info(mdev->dev, "omap mailbox rev 0x%x\n", l);
596 
597 	ret = pm_runtime_put_sync(mdev->dev);
598 	if (ret < 0 && ret != -ENOSYS)
599 		return ret;
600 
601 	return 0;
602 }
603 
604 static struct platform_driver omap_mbox_driver = {
605 	.probe	= omap_mbox_probe,
606 	.driver	= {
607 		.name = "omap-mailbox",
608 		.pm = &omap_mbox_pm_ops,
609 		.of_match_table = omap_mailbox_of_match,
610 	},
611 };
612 module_platform_driver(omap_mbox_driver);
613 
614 MODULE_LICENSE("GPL v2");
615 MODULE_DESCRIPTION("omap mailbox: interrupt driven messaging");
616 MODULE_AUTHOR("Toshihiro Kobayashi");
617 MODULE_AUTHOR("Hiroshi DOYU");
618