chrome_ec.c revision 297793
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: head/sys/arm/samsung/exynos/chrome_ec.c 297793 2016-04-10 23:07:00Z pfg $"); 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 61struct ec_softc { 62 device_t dev; 63 int have_arbitrator; 64 pcell_t our_gpio; 65 pcell_t ec_gpio; 66}; 67 68struct 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 76static int 77bus_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 110static int 111bus_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 131static int 132ec_probe(device_t dev) 133{ 134 135 device_set_desc(dev, "Chromebook Embedded Controller"); 136 return (BUS_PROBE_DEFAULT); 137} 138 139static int 140fill_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 155int 156ec_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 205int 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 221static void 222configure_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 243static int 244ec_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 270static int 271ec_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 284static 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 291static driver_t ec_driver = { 292 "chrome_ec", 293 ec_methods, 294 sizeof(struct ec_softc), 295}; 296 297static devclass_t ec_devclass; 298 299DRIVER_MODULE(chrome_ec, iicbus, ec_driver, ec_devclass, 0, 0); 300MODULE_VERSION(chrome_ec, 1); 301MODULE_DEPEND(chrome_ec, iicbus, 1, 1, 1); 302