xref: /freebsd/sys/powerpc/powernv/opal_i2c.c (revision 47dd1d1b619cc035b82b49a91a25544309ff95ae)
1 /*-
2  * Copyright (c) 2017-2018 QCM Technologies.
3  * Copyright (c) 2017-2018 Semihalf.
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  * $FreeBSD$
28  */
29 
30 #include "opt_platform.h"
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include <sys/param.h>
36 #include <sys/endian.h>
37 #include <sys/systm.h>
38 #include <sys/bus.h>
39 #include <sys/conf.h>
40 #include <sys/kernel.h>
41 #include <sys/lock.h>
42 #include <sys/mbuf.h>
43 #include <sys/malloc.h>
44 #include <sys/module.h>
45 #include <sys/mutex.h>
46 #include <sys/rman.h>
47 #include <machine/bus.h>
48 
49 #include <vm/vm.h>
50 #include <vm/pmap.h>
51 
52 #include <dev/iicbus/iiconf.h>
53 #include <dev/iicbus/iicbus.h>
54 #include "iicbus_if.h"
55 
56 #include "opal.h"
57 
58 #ifdef FDT
59 #include <dev/ofw/ofw_bus.h>
60 #include <dev/ofw/ofw_bus_subr.h>
61 #endif
62 
63 struct opal_i2c_softc
64 {
65 	device_t dev;
66 	device_t iicbus;
67 	uint32_t opal_id;
68 	struct mtx sc_mtx;
69 };
70 
71 /* OPAL I2C request */
72 struct opal_i2c_request {
73 	uint8_t type;
74 #define OPAL_I2C_RAW_READ	0
75 #define OPAL_I2C_RAW_WRITE	1
76 #define OPAL_I2C_SM_READ	2
77 #define OPAL_I2C_SM_WRITE	3
78 	uint8_t flags;
79 	uint8_t	subaddr_sz;		/* Max 4 */
80 	uint8_t reserved;
81 	uint16_t addr;			/* 7 or 10 bit address */
82 	uint16_t reserved2;
83 	uint32_t subaddr;		/* Sub-address if any */
84 	uint32_t size;			/* Data size */
85 	uint64_t buffer_pa;		/* Buffer real address */
86 };
87 
88 static int opal_i2c_attach(device_t);
89 static int opal_i2c_callback(device_t, int, caddr_t);
90 static int opal_i2c_probe(device_t);
91 static int opal_i2c_transfer(device_t, struct iic_msg *, uint32_t);
92 static int i2c_opal_send_request(uint32_t, struct opal_i2c_request *);
93 
94 static device_method_t opal_i2c_methods[] = {
95 	/* Device interface */
96 	DEVMETHOD(device_probe,		opal_i2c_probe),
97 	DEVMETHOD(device_attach,	opal_i2c_attach),
98 
99 	/* iicbus interface */
100 	DEVMETHOD(iicbus_callback,	opal_i2c_callback),
101 	DEVMETHOD(iicbus_transfer,	opal_i2c_transfer),
102 	DEVMETHOD_END
103 };
104 
105 #define	I2C_LOCK(_sc)		mtx_lock(&(_sc)->sc_mtx)
106 #define	I2C_UNLOCK(_sc)		mtx_unlock(&(_sc)->sc_mtx)
107 #define	I2C_LOCK_INIT(_sc) \
108 	mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->dev), \
109 	    "i2c", MTX_DEF)
110 
111 static devclass_t opal_i2c_devclass;
112 
113 static driver_t opal_i2c_driver = {
114 	"i2c",
115 	opal_i2c_methods,
116 	sizeof(struct opal_i2c_softc),
117 };
118 
119 static int
120 opal_i2c_probe(device_t dev)
121 {
122 
123 	if (!(ofw_bus_is_compatible(dev, "ibm,opal-i2c")))
124 		return (ENXIO);
125 
126 	device_set_desc(dev, "opal-i2c");
127 
128 	return (0);
129 }
130 
131 static int
132 opal_i2c_attach(device_t dev)
133 {
134 	struct opal_i2c_softc *sc;
135 	int len;
136 
137 	sc = device_get_softc(dev);
138 	sc->dev = dev;
139 
140 	len = OF_getproplen(ofw_bus_get_node(dev), "ibm,opal-id");
141 	if (len <= 0)
142 		return (EINVAL);
143 	OF_getencprop(ofw_bus_get_node(dev), "ibm,opal-id", &sc->opal_id, len);
144 
145 	if ((sc->iicbus = device_add_child(dev, "iicbus", -1)) == NULL) {
146 		device_printf(dev, "could not allocate iicbus instance\n");
147 		return (EINVAL);
148 	}
149 
150 	I2C_LOCK_INIT(sc);
151 
152 	return (bus_generic_attach(dev));
153 }
154 
155 static int
156 opal_get_async_rc(struct opal_msg msg)
157 {
158 	if (msg.msg_type != OPAL_MSG_ASYNC_COMP)
159 		return OPAL_PARAMETER;
160 	else
161 		return htobe64(msg.params[1]);
162 }
163 
164 static int
165 i2c_opal_send_request(uint32_t bus_id, struct opal_i2c_request *req)
166 {
167 	struct opal_msg msg;
168 	int token, rc;
169 
170 	/*
171 	 * XXX:
172 	 * Async tokens should be managed globally. Since there is
173 	 * only one place now, use hardcoded value.
174 	 */
175 	token = 0x112233;
176 
177 	memset(&msg, 0, sizeof(msg));
178 
179 	rc = opal_call(OPAL_I2C_REQUEST, token, bus_id,
180 	    pmap_kextract((uint64_t)req));
181 	if (rc != OPAL_ASYNC_COMPLETION)
182 		return (rc);
183 
184 	do {
185 		rc = opal_call(OPAL_CHECK_ASYNC_COMPLETION,
186 		    pmap_kextract((uint64_t)&msg), sizeof(msg), token);
187 	} while (rc == OPAL_BUSY);
188 
189 	if (rc != OPAL_SUCCESS)
190 		return (rc);
191 
192 	rc = opal_get_async_rc(msg);
193 
194 	return rc;
195 }
196 
197 static int
198 opal_i2c_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
199 {
200 	struct opal_i2c_softc *sc;
201 	int i, err = 0;
202 	struct opal_i2c_request req;
203 
204 	sc = device_get_softc(dev);
205 
206 	memset(&req, 0, sizeof(req));
207 
208 	/* XXX: Currently OPAL can parse only 1 message */
209 	if (nmsgs > 1) {
210 		device_printf(dev,
211 		    "trying to parse %d messages, while only 1 is supported\n", nmsgs);
212 		return (ENOMEM);
213 	}
214 
215 	I2C_LOCK(sc);
216 	for (i = 0; i < nmsgs; i++) {
217 		req.type = (msgs[i].flags & IIC_M_RD) ?
218 		    OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE;
219 		req.addr = htobe16(msgs[0].slave);
220 		req.size = htobe32(msgs[0].len);
221 		req.buffer_pa = htobe64(pmap_kextract((uint64_t)msgs[0].buf));
222 
223 		err = i2c_opal_send_request(sc->opal_id, &req);
224 	}
225 	I2C_UNLOCK(sc);
226 
227 	return (err);
228 }
229 
230 static int
231 opal_i2c_callback(device_t dev, int index, caddr_t data)
232 {
233 	int error = 0;
234 
235 	switch (index) {
236 	case IIC_REQUEST_BUS:
237 		break;
238 
239 	case IIC_RELEASE_BUS:
240 		break;
241 
242 	default:
243 		error = EINVAL;
244 	}
245 
246 	return (error);
247 }
248 
249 DRIVER_MODULE(opal_i2c, opal_i2cm, opal_i2c_driver, opal_i2c_devclass, NULL,
250     NULL);
251 DRIVER_MODULE(iicbus, opal_i2c, iicbus_driver, iicbus_devclass, NULL, NULL);
252 MODULE_DEPEND(opal_i2c, iicbus, 1, 1, 1);
253