bcm2835_mbox.c revision 1.15 
1/*	$NetBSD: bcm2835_mbox.c,v 1.15 2020/02/22 22:09:07 jmcneill Exp $	*/
2
3/*-
4 * Copyright (c) 2012 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Nick Hudson
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__KERNEL_RCSID(0, "$NetBSD: bcm2835_mbox.c,v 1.15 2020/02/22 22:09:07 jmcneill Exp $");
34
35#include <sys/param.h>
36#include <sys/systm.h>
37#include <sys/device.h>
38#include <sys/kernel.h>
39#include <sys/timetc.h>
40#include <sys/bus.h>
41#include <sys/mutex.h>
42
43#include <arm/broadcom/bcm2835_mbox.h>
44#include <arm/broadcom/bcm2835_mboxreg.h>
45#include <arm/broadcom/bcm2835reg.h>
46#include <arm/broadcom/bcm2835var.h>
47
48static struct bcm2835mbox_softc *bcm2835mbox_sc;
49
50static int
51bcmmbox_intr1(struct bcm2835mbox_softc *sc, int cv)
52{
53	uint32_t mbox, chan, data;
54	int ret = 0;
55
56	KASSERT(mutex_owned(&sc->sc_intr_lock));
57
58	bus_space_barrier(sc->sc_iot, sc->sc_ioh, 0, BCM2835_MBOX_SIZE,
59	    BUS_SPACE_BARRIER_READ);
60
61	while ((bus_space_read_4(sc->sc_iot, sc->sc_ioh,
62	    BCM2835_MBOX0_STATUS) & BCM2835_MBOX_STATUS_EMPTY) == 0) {
63
64		mbox = bus_space_read_4(sc->sc_iot, sc->sc_ioh,
65		    BCM2835_MBOX0_READ);
66
67		chan = BCM2835_MBOX_CHAN(mbox);
68		data = BCM2835_MBOX_DATA(mbox);
69		ret = 1;
70
71		if (BCM2835_MBOX_CHAN(sc->sc_mbox[chan]) != 0) {
72			aprint_error("bcmmbox_intr: chan %d overflow\n",chan);
73			continue;
74		}
75
76		sc->sc_mbox[chan] = data | BCM2835_MBOX_CHANMASK;
77
78		if (cv)
79			cv_broadcast(&sc->sc_chan[chan]);
80	}
81
82	return ret;
83}
84
85void
86bcmmbox_attach(struct bcm2835mbox_softc *sc)
87{
88	struct bcmmbox_attach_args baa;
89	int i;
90
91	if (bcm2835mbox_sc == NULL)
92		bcm2835mbox_sc = sc;
93
94	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);
95	mutex_init(&sc->sc_intr_lock, MUTEX_DEFAULT, IPL_VM);
96	for (i = 0; i < BCM2835_MBOX_NUMCHANNELS; ++i)
97		cv_init(&sc->sc_chan[i], "bcmmbox");
98
99	/* enable mbox interrupt */
100	if (sc->sc_intrh != NULL)
101		bus_space_write_4(sc->sc_iot, sc->sc_ioh, BCM2835_MBOX_CFG,
102		    BCM2835_MBOX_CFG_DATAIRQEN);
103
104	baa.baa_dmat = sc->sc_dmat;
105	sc->sc_platdev = config_found_ia(sc->sc_dev, "bcmmboxbus", &baa, NULL);
106}
107
108int
109bcmmbox_intr(void *cookie)
110{
111	struct bcm2835mbox_softc *sc = cookie;
112	int ret;
113
114	mutex_enter(&sc->sc_intr_lock);
115
116	ret = bcmmbox_intr1(sc, 1);
117
118	mutex_exit(&sc->sc_intr_lock);
119
120	return ret;
121}
122
123void
124bcmmbox_read(uint8_t chan, uint32_t *data)
125{
126	struct bcm2835mbox_softc *sc = bcm2835mbox_sc;
127
128	KASSERT(sc != NULL);
129
130	mutex_enter(&sc->sc_lock);
131
132	mutex_enter(&sc->sc_intr_lock);
133	while (BCM2835_MBOX_CHAN(sc->sc_mbox[chan]) == 0) {
134		if (cold || sc->sc_intrh == NULL)
135			bcmmbox_intr1(sc, 0);
136		else
137			cv_wait(&sc->sc_chan[chan], &sc->sc_intr_lock);
138	}
139	*data = BCM2835_MBOX_DATA(sc->sc_mbox[chan]);
140	sc->sc_mbox[chan] = 0;
141	mutex_exit(&sc->sc_intr_lock);
142
143	mutex_exit(&sc->sc_lock);
144}
145
146void
147bcmmbox_write(uint8_t chan, uint32_t data)
148{
149	struct bcm2835mbox_softc *sc = bcm2835mbox_sc;
150
151	KASSERT(sc != NULL);
152	KASSERT(BCM2835_MBOX_CHAN(chan) == chan);
153	KASSERT(BCM2835_MBOX_CHAN(data) == 0);
154
155	mutex_enter(&sc->sc_lock);
156
157	bcm2835_mbox_write(sc->sc_iot, sc->sc_ioh, chan, data);
158
159	mutex_exit(&sc->sc_lock);
160}
161
162int
163bcmmbox_request(uint8_t chan, void *buf, size_t buflen, uint32_t *pres)
164{
165	struct bcm2835mbox_softc *sc = bcm2835mbox_sc;
166	void *dma_buf;
167	bus_dmamap_t map;
168	bus_dma_segment_t segs[1];
169	int nsegs;
170	int error;
171
172	KASSERT(sc != NULL);
173
174	error = bus_dmamem_alloc(sc->sc_dmat, buflen, 16, 0, segs, 1,
175	    &nsegs, BUS_DMA_WAITOK);
176	if (error)
177		return error;
178	error = bus_dmamem_map(sc->sc_dmat, segs, nsegs, buflen, &dma_buf,
179	    BUS_DMA_WAITOK);
180	if (error)
181		goto map_failed;
182	error = bus_dmamap_create(sc->sc_dmat, buflen, 1, buflen, 0,
183	    BUS_DMA_WAITOK, &map);
184	if (error)
185		goto create_failed;
186	error = bus_dmamap_load(sc->sc_dmat, map, dma_buf, buflen, NULL,
187	    BUS_DMA_WAITOK);
188	if (error)
189		goto load_failed;
190
191	memcpy(dma_buf, buf, buflen);
192
193	bus_dmamap_sync(sc->sc_dmat, map, 0, buflen,
194	     BUS_DMASYNC_PREWRITE|BUS_DMASYNC_PREREAD);
195	bcmmbox_write(chan, map->dm_segs[0].ds_addr);
196	bcmmbox_read(chan, pres);
197	bus_dmamap_sync(sc->sc_dmat, map, 0, buflen,
198	    BUS_DMASYNC_POSTWRITE|BUS_DMASYNC_POSTREAD);
199
200	memcpy(buf, dma_buf, buflen);
201
202	bus_dmamap_unload(sc->sc_dmat, map);
203load_failed:
204	bus_dmamap_destroy(sc->sc_dmat, map);
205create_failed:
206	bus_dmamem_unmap(sc->sc_dmat, dma_buf, buflen);
207map_failed:
208	bus_dmamem_free(sc->sc_dmat, segs, nsegs);
209
210	return error;
211}
212