1 /*-
2 * Copyright (c) 2014 Ruslan Bukin <br@bsdpad.com>
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 EXPREC OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNEC 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 BUSINEC 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 /*
28 * Samsung Chromebook Embedded Controller
29 */
30
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/bus.h>
37 #include <sys/kernel.h>
38 #include <sys/module.h>
39 #include <sys/malloc.h>
40 #include <sys/rman.h>
41 #include <sys/timeet.h>
42 #include <sys/timetc.h>
43 #include <sys/watchdog.h>
44 #include <sys/gpio.h>
45
46 #include <dev/ofw/openfirm.h>
47 #include <dev/ofw/ofw_bus.h>
48 #include <dev/ofw/ofw_bus_subr.h>
49
50 #include <machine/bus.h>
51 #include <machine/cpu.h>
52 #include <machine/intr.h>
53
54 #include <dev/iicbus/iiconf.h>
55
56 #include "iicbus_if.h"
57 #include "gpio_if.h"
58
59 #include <arm/samsung/exynos/chrome_ec.h>
60
61 struct ec_softc {
62 device_t dev;
63 int have_arbitrator;
64 pcell_t our_gpio;
65 pcell_t ec_gpio;
66 };
67
68 struct ec_softc *ec_sc;
69
70 /*
71 * bus_claim, bus_release
72 * both functions used for bus arbitration
73 * in multi-master mode
74 */
75
76 static int
bus_claim(struct ec_softc * sc)77 bus_claim(struct ec_softc *sc)
78 {
79 device_t gpio_dev;
80 int status;
81
82 if (sc->our_gpio == 0 || sc->ec_gpio == 0) {
83 device_printf(sc->dev, "i2c arbitrator is not configured\n");
84 return (1);
85 }
86
87 gpio_dev = devclass_get_device(devclass_find("gpio"), 0);
88 if (gpio_dev == NULL) {
89 device_printf(sc->dev, "cant find gpio_dev\n");
90 return (1);
91 }
92
93 /* Say we want the bus */
94 GPIO_PIN_SET(gpio_dev, sc->our_gpio, GPIO_PIN_LOW);
95
96 /* TODO: insert a delay to allow EC to react. */
97
98 /* Check EC decision */
99 GPIO_PIN_GET(gpio_dev, sc->ec_gpio, &status);
100
101 if (status == 1) {
102 /* Okay. We have bus */
103 return (0);
104 }
105
106 /* EC is master */
107 return (-1);
108 }
109
110 static int
bus_release(struct ec_softc * sc)111 bus_release(struct ec_softc *sc)
112 {
113 device_t gpio_dev;
114
115 if (sc->our_gpio == 0 || sc->ec_gpio == 0) {
116 device_printf(sc->dev, "i2c arbitrator is not configured\n");
117 return (1);
118 }
119
120 gpio_dev = devclass_get_device(devclass_find("gpio"), 0);
121 if (gpio_dev == NULL) {
122 device_printf(sc->dev, "cant find gpio_dev\n");
123 return (1);
124 }
125
126 GPIO_PIN_SET(gpio_dev, sc->our_gpio, GPIO_PIN_HIGH);
127
128 return (0);
129 }
130
131 static int
ec_probe(device_t dev)132 ec_probe(device_t dev)
133 {
134
135 device_set_desc(dev, "Chromebook Embedded Controller");
136 return (BUS_PROBE_DEFAULT);
137 }
138
139 static int
fill_checksum(uint8_t * data_out,int len)140 fill_checksum(uint8_t *data_out, int len)
141 {
142 int res;
143 int i;
144
145 res = 0;
146 for (i = 0; i < len; i++) {
147 res += data_out[i];
148 }
149
150 data_out[len] = (res & 0xff);
151
152 return (0);
153 }
154
155 int
ec_command(uint8_t cmd,uint8_t * dout,uint8_t dout_len,uint8_t * dinp,uint8_t dinp_len)156 ec_command(uint8_t cmd, uint8_t *dout, uint8_t dout_len,
157 uint8_t *dinp, uint8_t dinp_len)
158 {
159 struct ec_softc *sc;
160 uint8_t *msg_dout;
161 uint8_t *msg_dinp;
162 int ret;
163 int i;
164
165 msg_dout = malloc(dout_len + 4, M_DEVBUF, M_NOWAIT);
166 msg_dinp = malloc(dinp_len + 3, M_DEVBUF, M_NOWAIT);
167
168 if (ec_sc == NULL)
169 return (-1);
170
171 sc = ec_sc;
172
173 msg_dout[0] = EC_CMD_VERSION0;
174 msg_dout[1] = cmd;
175 msg_dout[2] = dout_len;
176
177 for (i = 0; i < dout_len; i++) {
178 msg_dout[i + 3] = dout[i];
179 };
180
181 fill_checksum(msg_dout, dout_len + 3);
182
183 struct iic_msg msgs[] = {
184 { 0x1e, IIC_M_WR, dout_len + 4, msg_dout, },
185 { 0x1e, IIC_M_RD, dinp_len + 3, msg_dinp, },
186 };
187
188 ret = iicbus_transfer(sc->dev, msgs, 2);
189 if (ret != 0) {
190 device_printf(sc->dev, "i2c transfer returned %d\n", ret);
191 free(msg_dout, M_DEVBUF);
192 free(msg_dinp, M_DEVBUF);
193 return (-1);
194 }
195
196 for (i = 0; i < dinp_len; i++) {
197 dinp[i] = msg_dinp[i + 2];
198 };
199
200 free(msg_dout, M_DEVBUF);
201 free(msg_dinp, M_DEVBUF);
202 return (0);
203 }
204
ec_hello(void)205 int ec_hello(void)
206 {
207 uint8_t data_in[4];
208 uint8_t data_out[4];
209
210 data_in[0] = 0x40;
211 data_in[1] = 0x30;
212 data_in[2] = 0x20;
213 data_in[3] = 0x10;
214
215 ec_command(EC_CMD_HELLO, data_in, 4,
216 data_out, 4);
217
218 return (0);
219 }
220
221 static void
configure_i2c_arbitrator(struct ec_softc * sc)222 configure_i2c_arbitrator(struct ec_softc *sc)
223 {
224 phandle_t arbitrator;
225
226 /* TODO: look for compatible entry instead of hard-coded path */
227 arbitrator = OF_finddevice("/i2c-arbitrator");
228 if (arbitrator > 0 &&
229 OF_hasprop(arbitrator, "freebsd,our-gpio") &&
230 OF_hasprop(arbitrator, "freebsd,ec-gpio")) {
231 sc->have_arbitrator = 1;
232 OF_getencprop(arbitrator, "freebsd,our-gpio",
233 &sc->our_gpio, sizeof(sc->our_gpio));
234 OF_getencprop(arbitrator, "freebsd,ec-gpio",
235 &sc->ec_gpio, sizeof(sc->ec_gpio));
236 } else {
237 sc->have_arbitrator = 0;
238 sc->our_gpio = 0;
239 sc->ec_gpio = 0;
240 }
241 }
242
243 static int
ec_attach(device_t dev)244 ec_attach(device_t dev)
245 {
246 struct ec_softc *sc;
247
248 sc = device_get_softc(dev);
249 sc->dev = dev;
250
251 ec_sc = sc;
252
253 configure_i2c_arbitrator(sc);
254
255 /*
256 * Claim the bus.
257 *
258 * We don't know cases when EC is master,
259 * so hold the bus forever for us.
260 *
261 */
262
263 if (sc->have_arbitrator && bus_claim(sc) != 0) {
264 return (ENXIO);
265 }
266
267 return (0);
268 }
269
270 static int
ec_detach(device_t dev)271 ec_detach(device_t dev)
272 {
273 struct ec_softc *sc;
274
275 sc = device_get_softc(dev);
276
277 if (sc->have_arbitrator) {
278 bus_release(sc);
279 }
280
281 return (0);
282 }
283
284 static device_method_t ec_methods[] = {
285 DEVMETHOD(device_probe, ec_probe),
286 DEVMETHOD(device_attach, ec_attach),
287 DEVMETHOD(device_detach, ec_detach),
288 { 0, 0 }
289 };
290
291 static driver_t ec_driver = {
292 "chrome_ec",
293 ec_methods,
294 sizeof(struct ec_softc),
295 };
296
297 static devclass_t ec_devclass;
298
299 DRIVER_MODULE(chrome_ec, iicbus, ec_driver, ec_devclass, 0, 0);
300 MODULE_VERSION(chrome_ec, 1);
301 MODULE_DEPEND(chrome_ec, iicbus, 1, 1, 1);
302