xref: /freebsd/sys/arm/broadcom/bcm2835/bcm2835_mbox.c (revision f4b37ed0f8b307b1f3f0f630ca725d68f1dff30d)
1 /*-
2  * Copyright (c) 2012 Oleksandr Tymoshenko <gonzo@freebsd.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/bus.h>
33 #include <sys/kernel.h>
34 #include <sys/lock.h>
35 #include <sys/module.h>
36 #include <sys/mutex.h>
37 #include <sys/rman.h>
38 #include <sys/sema.h>
39 #include <machine/bus.h>
40 
41 #include <dev/ofw/ofw_bus.h>
42 #include <dev/ofw/ofw_bus_subr.h>
43 
44 #include <arm/broadcom/bcm2835/bcm2835_mbox.h>
45 #include <arm/broadcom/bcm2835/bcm2835_mbox_prop.h>
46 #include <arm/broadcom/bcm2835/bcm2835_vcbus.h>
47 
48 #include "mbox_if.h"
49 
50 #define	REG_READ	0x00
51 #define	REG_POL		0x10
52 #define	REG_SENDER	0x14
53 #define	REG_STATUS	0x18
54 #define		STATUS_FULL	0x80000000
55 #define		STATUS_EMPTY	0x40000000
56 #define	REG_CONFIG	0x1C
57 #define		CONFIG_DATA_IRQ	0x00000001
58 #define	REG_WRITE	0x20 /* This is Mailbox 1 address */
59 
60 #define	MBOX_MSG(chan, data)	(((data) & ~0xf) | ((chan) & 0xf))
61 #define	MBOX_CHAN(msg)		((msg) & 0xf)
62 #define	MBOX_DATA(msg)		((msg) & ~0xf)
63 
64 #define	MBOX_LOCK(sc)	do {	\
65 	mtx_lock(&(sc)->lock);	\
66 } while(0)
67 
68 #define	MBOX_UNLOCK(sc)	do {		\
69 	mtx_unlock(&(sc)->lock);	\
70 } while(0)
71 
72 #ifdef  DEBUG
73 #define dprintf(fmt, args...) printf(fmt, ##args)
74 #else
75 #define dprintf(fmt, args...)
76 #endif
77 
78 struct bcm_mbox_softc {
79 	struct mtx		lock;
80 	struct resource *	mem_res;
81 	struct resource *	irq_res;
82 	void*			intr_hl;
83 	bus_space_tag_t		bst;
84 	bus_space_handle_t	bsh;
85 	int			msg[BCM2835_MBOX_CHANS];
86 	struct sema		sema[BCM2835_MBOX_CHANS];
87 };
88 
89 #define	mbox_read_4(sc, reg)		\
90     bus_space_read_4((sc)->bst, (sc)->bsh, reg)
91 #define	mbox_write_4(sc, reg, val)		\
92     bus_space_write_4((sc)->bst, (sc)->bsh, reg, val)
93 
94 static int
95 bcm_mbox_read_msg(struct bcm_mbox_softc *sc, int *ochan)
96 {
97 	uint32_t data;
98 	uint32_t msg;
99 	int chan;
100 
101 	msg = mbox_read_4(sc, REG_READ);
102 	dprintf("bcm_mbox_intr: raw data %08x\n", msg);
103 	chan = MBOX_CHAN(msg);
104 	data = MBOX_DATA(msg);
105 	if (sc->msg[chan]) {
106 		printf("bcm_mbox_intr: channel %d oveflow\n", chan);
107 		return (1);
108 	}
109 	dprintf("bcm_mbox_intr: chan %d, data %08x\n", chan, data);
110 	sc->msg[chan] = msg;
111 
112 	if (ochan != NULL)
113 		*ochan = chan;
114 
115 	return (0);
116 }
117 
118 static void
119 bcm_mbox_intr(void *arg)
120 {
121 	struct bcm_mbox_softc *sc = arg;
122 	int chan;
123 
124 	while (!(mbox_read_4(sc, REG_STATUS) & STATUS_EMPTY))
125 		if (bcm_mbox_read_msg(sc, &chan) == 0)
126 			sema_post(&sc->sema[chan]);
127 }
128 
129 static int
130 bcm_mbox_probe(device_t dev)
131 {
132 
133 	if (!ofw_bus_status_okay(dev))
134 		return (ENXIO);
135 
136 	if (ofw_bus_is_compatible(dev, "broadcom,bcm2835-mbox")) {
137 		device_set_desc(dev, "BCM2835 VideoCore Mailbox");
138 		return(BUS_PROBE_DEFAULT);
139 	}
140 
141 	return (ENXIO);
142 }
143 
144 static int
145 bcm_mbox_attach(device_t dev)
146 {
147 	struct bcm_mbox_softc *sc = device_get_softc(dev);
148 	int i;
149 	int rid = 0;
150 
151 	sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
152 	if (sc->mem_res == NULL) {
153 		device_printf(dev, "could not allocate memory resource\n");
154 		return (ENXIO);
155 	}
156 
157 	sc->bst = rman_get_bustag(sc->mem_res);
158 	sc->bsh = rman_get_bushandle(sc->mem_res);
159 
160 	rid = 0;
161 	sc->irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid, RF_ACTIVE);
162 	if (sc->irq_res == NULL) {
163 		device_printf(dev, "could not allocate interrupt resource\n");
164 		return (ENXIO);
165 	}
166 
167 	/* Setup and enable the timer */
168 	if (bus_setup_intr(dev, sc->irq_res, INTR_MPSAFE | INTR_TYPE_MISC,
169 	    NULL, bcm_mbox_intr, sc, &sc->intr_hl) != 0) {
170 		bus_release_resource(dev, SYS_RES_IRQ, rid, sc->irq_res);
171 		device_printf(dev, "Unable to setup the clock irq handler.\n");
172 		return (ENXIO);
173 	}
174 
175 	mtx_init(&sc->lock, "vcio mbox", NULL, MTX_DEF);
176 	for (i = 0; i < BCM2835_MBOX_CHANS; i++) {
177 		sc->msg[i] = 0;
178 		sema_init(&sc->sema[i], 0, "mbox");
179 	}
180 
181 	/* Read all pending messages */
182 	while ((mbox_read_4(sc, REG_STATUS) & STATUS_EMPTY) == 0)
183 		(void)mbox_read_4(sc, REG_READ);
184 
185 	mbox_write_4(sc, REG_CONFIG, CONFIG_DATA_IRQ);
186 
187 	return (0);
188 }
189 
190 /*
191  * Mailbox API
192  */
193 static int
194 bcm_mbox_write(device_t dev, int chan, uint32_t data)
195 {
196 	int limit = 1000;
197 	struct bcm_mbox_softc *sc = device_get_softc(dev);
198 
199 	dprintf("bcm_mbox_write: chan %d, data %08x\n", chan, data);
200 	MBOX_LOCK(sc);
201 	while ((mbox_read_4(sc, REG_STATUS) & STATUS_FULL) && --limit)
202 		DELAY(5);
203 	if (limit == 0) {
204 		printf("bcm_mbox_write: STATUS_FULL stuck");
205 		MBOX_UNLOCK(sc);
206 		return (EAGAIN);
207 	}
208 	mbox_write_4(sc, REG_WRITE, MBOX_MSG(chan, data));
209 	MBOX_UNLOCK(sc);
210 
211 	return (0);
212 }
213 
214 static int
215 bcm_mbox_read(device_t dev, int chan, uint32_t *data)
216 {
217 	struct bcm_mbox_softc *sc = device_get_softc(dev);
218 	int err, read_chan;
219 
220 	dprintf("bcm_mbox_read: chan %d\n", chan);
221 
222 	err = 0;
223 	MBOX_LOCK(sc);
224 	if (!cold) {
225 		while (sema_trywait(&sc->sema[chan]) == 0) {
226 			/* do not unlock sc while waiting for the mbox */
227 			if (sema_timedwait(&sc->sema[chan], 10*hz) == 0)
228 				break;
229 			printf("timeout sema for chan %d\n", chan);
230 		}
231 	} else {
232 		do {
233 			/* Wait for a message */
234 			while ((mbox_read_4(sc, REG_STATUS) & STATUS_EMPTY))
235 				;
236 			/* Read the message */
237 			if (bcm_mbox_read_msg(sc, &read_chan) != 0) {
238 				err = EINVAL;
239 				goto out;
240 			}
241 		} while (read_chan != chan);
242 	}
243 	/*
244 	 *  get data from intr handler, the same channel is never coming
245 	 *  because of holding sc lock.
246 	 */
247 	*data = MBOX_DATA(sc->msg[chan]);
248 	sc->msg[chan] = 0;
249 out:
250 	MBOX_UNLOCK(sc);
251 	dprintf("bcm_mbox_read: chan %d, data %08x\n", chan, *data);
252 
253 	return (err);
254 }
255 
256 static device_method_t bcm_mbox_methods[] = {
257 	DEVMETHOD(device_probe,		bcm_mbox_probe),
258 	DEVMETHOD(device_attach,	bcm_mbox_attach),
259 
260 	DEVMETHOD(mbox_read,		bcm_mbox_read),
261 	DEVMETHOD(mbox_write,		bcm_mbox_write),
262 
263 	DEVMETHOD_END
264 };
265 
266 static driver_t bcm_mbox_driver = {
267 	"mbox",
268 	bcm_mbox_methods,
269 	sizeof(struct bcm_mbox_softc),
270 };
271 
272 static devclass_t bcm_mbox_devclass;
273 
274 DRIVER_MODULE(mbox, simplebus, bcm_mbox_driver, bcm_mbox_devclass, 0, 0);
275 
276 static void
277 bcm2835_mbox_dma_cb(void *arg, bus_dma_segment_t *segs, int nseg, int err)
278 {
279 	bus_addr_t *addr;
280 
281 	if (err)
282 		return;
283 	addr = (bus_addr_t *)arg;
284 	*addr = PHYS_TO_VCBUS(segs[0].ds_addr);
285 }
286 
287 static void *
288 bcm2835_mbox_init_dma(device_t dev, size_t len, bus_dma_tag_t *tag,
289     bus_dmamap_t *map, bus_addr_t *phys)
290 {
291 	void *buf;
292 	int err;
293 
294 	err = bus_dma_tag_create(bus_get_dma_tag(dev), 16, 0,
295 	    BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL, NULL,
296 	    len, 1, len, 0, NULL, NULL, tag);
297 	if (err != 0) {
298 		device_printf(dev, "can't create DMA tag\n");
299 		return (NULL);
300 	}
301 
302 	err = bus_dmamem_alloc(*tag, &buf, 0, map);
303 	if (err != 0) {
304 		bus_dma_tag_destroy(*tag);
305 		device_printf(dev, "can't allocate dmamem\n");
306 		return (NULL);
307 	}
308 
309 	err = bus_dmamap_load(*tag, *map, buf, len, bcm2835_mbox_dma_cb,
310 	    phys, 0);
311 	if (err != 0) {
312 		bus_dmamem_free(*tag, buf, *map);
313 		bus_dma_tag_destroy(*tag);
314 		device_printf(dev, "can't load DMA map\n");
315 		return (NULL);
316 	}
317 
318 	return (buf);
319 }
320 
321 static int
322 bcm2835_mbox_err(device_t dev, bus_addr_t msg_phys, uint32_t resp_phys,
323 	struct bcm2835_mbox_hdr *msg, size_t len)
324 {
325 	int idx;
326 	struct bcm2835_mbox_tag_hdr *tag;
327 	uint8_t *last;
328 
329 	if ((uint32_t)msg_phys != resp_phys) {
330 		device_printf(dev, "response channel mismatch\n");
331 		return (EIO);
332 	}
333 	if (msg->code != BCM2835_MBOX_CODE_RESP_SUCCESS) {
334 		device_printf(dev, "mbox response error\n");
335 		return (EIO);
336 	}
337 
338 	/* Loop until the end tag. */
339 	tag = (struct bcm2835_mbox_tag_hdr *)(msg + 1);
340 	last = (uint8_t *)msg + len;
341 	for (idx = 0; tag->tag != 0; idx++) {
342 		if ((tag->val_len & BCM2835_MBOX_TAG_VAL_LEN_RESPONSE) == 0) {
343 			device_printf(dev, "tag %d response error\n", idx);
344 			return (EIO);
345 		}
346 		/* Clear the response bit. */
347 		tag->val_len &= ~BCM2835_MBOX_TAG_VAL_LEN_RESPONSE;
348 
349 		/* Next tag. */
350 		tag = (struct bcm2835_mbox_tag_hdr *)((uint8_t *)tag +
351 		    sizeof(*tag) + tag->val_buf_size);
352 
353 		if ((uint8_t *)tag > last) {
354 			device_printf(dev, "mbox buffer size error\n");
355 			return (EIO);
356 		}
357 	}
358 
359 	return (0);
360 }
361 
362 int
363 bcm2835_mbox_set_power_state(device_t dev, uint32_t device_id, boolean_t on)
364 {
365 	struct msg_set_power_state *msg;
366 	bus_dma_tag_t msg_tag;
367 	bus_dmamap_t msg_map;
368 	bus_addr_t msg_phys;
369 	uint32_t reg;
370 	device_t mbox;
371 
372 	/* get mbox device */
373 	mbox = devclass_get_device(devclass_find("mbox"), 0);
374 	if (mbox == NULL) {
375 		device_printf(dev, "can't find mbox\n");
376 		return (ENXIO);
377 	}
378 
379 	/* Allocate memory for the message */
380 	msg = bcm2835_mbox_init_dma(dev, sizeof(*msg), &msg_tag, &msg_map,
381 	    &msg_phys);
382 	if (msg == NULL)
383 		return (ENOMEM);
384 
385 	memset(msg, 0, sizeof(*msg));
386 	msg->hdr.buf_size = sizeof(*msg);
387 	msg->hdr.code = BCM2835_MBOX_CODE_REQ;
388 	msg->tag_hdr.tag = BCM2835_MBOX_TAG_SET_POWER_STATE;
389 	msg->tag_hdr.val_buf_size = sizeof(msg->body);
390 	msg->tag_hdr.val_len = sizeof(msg->body.req);
391 	msg->body.req.device_id = device_id;
392 	msg->body.req.state = (on ? BCM2835_MBOX_POWER_ON : 0) |
393 	    BCM2835_MBOX_POWER_WAIT;
394 	msg->end_tag = 0;
395 
396 	bus_dmamap_sync(msg_tag, msg_map,
397 	    BUS_DMASYNC_PREWRITE | BUS_DMASYNC_PREREAD);
398 
399 	MBOX_WRITE(mbox, BCM2835_MBOX_CHAN_PROP, (uint32_t)msg_phys);
400 	MBOX_READ(mbox, BCM2835_MBOX_CHAN_PROP, &reg);
401 
402 	bus_dmamap_unload(msg_tag, msg_map);
403 	bus_dmamem_free(msg_tag, msg, msg_map);
404 	bus_dma_tag_destroy(msg_tag);
405 
406 	return (0);
407 }
408 
409 int
410 bcm2835_mbox_get_clock_rate(device_t dev, uint32_t clock_id, uint32_t *hz)
411 {
412 	struct msg_get_clock_rate *msg;
413 	bus_dma_tag_t msg_tag;
414 	bus_dmamap_t msg_map;
415 	bus_addr_t msg_phys;
416 	uint32_t reg;
417 	device_t mbox;
418 
419 	/* get mbox device */
420 	mbox = devclass_get_device(devclass_find("mbox"), 0);
421 	if (mbox == NULL) {
422 		device_printf(dev, "can't find mbox\n");
423 		return (ENXIO);
424 	}
425 
426 	/* Allocate memory for the message */
427 	msg = bcm2835_mbox_init_dma(dev, sizeof(*msg), &msg_tag, &msg_map,
428 	    &msg_phys);
429 	if (msg == NULL)
430 		return (ENOMEM);
431 
432 	memset(msg, 0, sizeof(*msg));
433 	msg->hdr.buf_size = sizeof(*msg);
434 	msg->hdr.code = BCM2835_MBOX_CODE_REQ;
435 	msg->tag_hdr.tag = BCM2835_MBOX_TAG_GET_CLOCK_RATE;
436 	msg->tag_hdr.val_buf_size = sizeof(msg->body);
437 	msg->tag_hdr.val_len = sizeof(msg->body.req);
438 	msg->body.req.clock_id = clock_id;
439 	msg->end_tag = 0;
440 
441 	bus_dmamap_sync(msg_tag, msg_map, BUS_DMASYNC_PREWRITE);
442 	MBOX_WRITE(mbox, BCM2835_MBOX_CHAN_PROP, (uint32_t)msg_phys);
443 	bus_dmamap_sync(msg_tag, msg_map, BUS_DMASYNC_POSTWRITE);
444 
445 	bus_dmamap_sync(msg_tag, msg_map, BUS_DMASYNC_PREREAD);
446 	MBOX_READ(mbox, BCM2835_MBOX_CHAN_PROP, &reg);
447 	bus_dmamap_sync(msg_tag, msg_map, BUS_DMASYNC_POSTREAD);
448 
449 	*hz = msg->body.resp.rate_hz;
450 
451 	bus_dmamap_unload(msg_tag, msg_map);
452 	bus_dmamem_free(msg_tag, msg, msg_map);
453 	bus_dma_tag_destroy(msg_tag);
454 
455 	return (0);
456 }
457 
458 int
459 bcm2835_mbox_fb_get_w_h(device_t dev, struct bcm2835_fb_config *fb)
460 {
461 	device_t mbox;
462 	int err;
463 	bus_dma_tag_t msg_tag;
464 	bus_dmamap_t msg_map;
465 	bus_addr_t msg_phys;
466 	struct msg_fb_get_w_h *msg;
467 	uint32_t reg;
468 
469 	/* get mbox device */
470 	mbox = devclass_get_device(devclass_find("mbox"), 0);
471 	if (mbox == NULL) {
472 		device_printf(dev, "can't find mbox\n");
473 		return (ENXIO);
474 	}
475 
476 	/* Allocate memory for the message */
477 	msg = bcm2835_mbox_init_dma(dev, sizeof(*msg), &msg_tag, &msg_map,
478 	    &msg_phys);
479 	if (msg == NULL)
480 		return (ENOMEM);
481 
482 	memset(msg, 0, sizeof(*msg));
483 	msg->hdr.buf_size = sizeof(*msg);
484 	msg->hdr.code = BCM2835_MBOX_CODE_REQ;
485 	BCM2835_MBOX_INIT_TAG(&msg->physical_w_h, GET_PHYSICAL_W_H);
486 	msg->physical_w_h.tag_hdr.val_len = 0;
487 	BCM2835_MBOX_INIT_TAG(&msg->virtual_w_h, GET_VIRTUAL_W_H);
488 	msg->virtual_w_h.tag_hdr.val_len = 0;
489 	BCM2835_MBOX_INIT_TAG(&msg->offset, GET_VIRTUAL_OFFSET);
490 	msg->offset.tag_hdr.val_len = 0;
491 	msg->end_tag = 0;
492 
493 	bus_dmamap_sync(msg_tag, msg_map, BUS_DMASYNC_PREWRITE);
494 	MBOX_WRITE(mbox, BCM2835_MBOX_CHAN_PROP, (uint32_t)msg_phys);
495 	bus_dmamap_sync(msg_tag, msg_map, BUS_DMASYNC_POSTWRITE);
496 
497 	bus_dmamap_sync(msg_tag, msg_map, BUS_DMASYNC_PREREAD);
498 	MBOX_READ(mbox, BCM2835_MBOX_CHAN_PROP, &reg);
499 	bus_dmamap_sync(msg_tag, msg_map, BUS_DMASYNC_POSTREAD);
500 
501 	err = bcm2835_mbox_err(dev, msg_phys, reg, &msg->hdr, sizeof(*msg));
502 	if (err == 0) {
503 		fb->xres = msg->physical_w_h.body.resp.width;
504 		fb->yres = msg->physical_w_h.body.resp.height;
505 		fb->vxres = msg->virtual_w_h.body.resp.width;
506 		fb->vyres = msg->virtual_w_h.body.resp.height;
507 		fb->xoffset = msg->offset.body.resp.x;
508 		fb->yoffset = msg->offset.body.resp.y;
509 	}
510 
511 	bus_dmamap_unload(msg_tag, msg_map);
512 	bus_dmamem_free(msg_tag, msg, msg_map);
513 	bus_dma_tag_destroy(msg_tag);
514 
515 	return (err);
516 }
517 
518 int
519 bcm2835_mbox_fb_init(device_t dev, struct bcm2835_fb_config *fb)
520 {
521 	device_t mbox;
522 	int err;
523 	bus_dma_tag_t msg_tag;
524 	bus_dmamap_t msg_map;
525 	bus_addr_t msg_phys;
526 	struct msg_fb_setup *msg;
527 	uint32_t reg;
528 
529 	/* get mbox device */
530 	mbox = devclass_get_device(devclass_find("mbox"), 0);
531 	if (mbox == NULL) {
532 		device_printf(dev, "can't find mbox\n");
533 		return (ENXIO);
534 	}
535 
536 	/* Allocate memory for the message */
537 	msg = bcm2835_mbox_init_dma(dev, sizeof(*msg), &msg_tag, &msg_map,
538 	    &msg_phys);
539 	if (msg == NULL)
540 		return (ENOMEM);
541 
542 	memset(msg, 0, sizeof(*msg));
543 	msg->hdr.buf_size = sizeof(*msg);
544 	msg->hdr.code = BCM2835_MBOX_CODE_REQ;
545 	BCM2835_MBOX_INIT_TAG(&msg->physical_w_h, SET_PHYSICAL_W_H);
546 	msg->physical_w_h.body.req.width = fb->xres;
547 	msg->physical_w_h.body.req.height = fb->yres;
548 	BCM2835_MBOX_INIT_TAG(&msg->virtual_w_h, SET_VIRTUAL_W_H);
549 	msg->virtual_w_h.body.req.width = fb->vxres;
550 	msg->virtual_w_h.body.req.height = fb->vyres;
551 	BCM2835_MBOX_INIT_TAG(&msg->offset, GET_VIRTUAL_OFFSET);
552 	msg->offset.body.req.x = fb->xoffset;
553 	msg->offset.body.req.y = fb->yoffset;
554 	BCM2835_MBOX_INIT_TAG(&msg->depth, SET_DEPTH);
555 	msg->depth.body.req.bpp = fb->bpp;
556 	BCM2835_MBOX_INIT_TAG(&msg->alpha, SET_ALPHA_MODE);
557 	msg->alpha.body.req.alpha = BCM2835_MBOX_ALPHA_MODE_IGNORED;
558 	BCM2835_MBOX_INIT_TAG(&msg->buffer, ALLOCATE_BUFFER);
559 	msg->buffer.body.req.alignment = PAGE_SIZE;
560 	BCM2835_MBOX_INIT_TAG(&msg->pitch, GET_PITCH);
561 	msg->end_tag = 0;
562 
563 	bus_dmamap_sync(msg_tag, msg_map, BUS_DMASYNC_PREWRITE);
564 	MBOX_WRITE(mbox, BCM2835_MBOX_CHAN_PROP, (uint32_t)msg_phys);
565 	bus_dmamap_sync(msg_tag, msg_map, BUS_DMASYNC_POSTWRITE);
566 
567 	bus_dmamap_sync(msg_tag, msg_map, BUS_DMASYNC_PREREAD);
568 	MBOX_READ(mbox, BCM2835_MBOX_CHAN_PROP, &reg);
569 	bus_dmamap_sync(msg_tag, msg_map, BUS_DMASYNC_POSTREAD);
570 
571 	err = bcm2835_mbox_err(dev, msg_phys, reg, &msg->hdr, sizeof(*msg));
572 	if (err == 0) {
573 		fb->xres = msg->physical_w_h.body.resp.width;
574 		fb->yres = msg->physical_w_h.body.resp.height;
575 		fb->vxres = msg->virtual_w_h.body.resp.width;
576 		fb->vyres = msg->virtual_w_h.body.resp.height;
577 		fb->xoffset = msg->offset.body.resp.x;
578 		fb->yoffset = msg->offset.body.resp.y;
579 		fb->pitch = msg->pitch.body.resp.pitch;
580 		fb->base = msg->buffer.body.resp.fb_address;
581 		fb->size = msg->buffer.body.resp.fb_size;
582 	}
583 
584 	bus_dmamap_unload(msg_tag, msg_map);
585 	bus_dmamem_free(msg_tag, msg, msg_map);
586 	bus_dma_tag_destroy(msg_tag);
587 
588 	return (err);
589 }
590