302 lines
6.2 KiB
C
302 lines
6.2 KiB
C
/*-
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* Copyright (c) 2014 Ruslan Bukin <br@bsdpad.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPREC OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNEC FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINEC INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Samsung Chromebook Embedded Controller
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#include <sys/malloc.h>
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#include <sys/rman.h>
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#include <sys/timeet.h>
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#include <sys/timetc.h>
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#include <sys/watchdog.h>
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#include <sys/gpio.h>
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#include <dev/ofw/openfirm.h>
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#include <dev/ofw/ofw_bus.h>
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#include <dev/ofw/ofw_bus_subr.h>
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#include <machine/bus.h>
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#include <machine/cpu.h>
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#include <machine/intr.h>
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#include <dev/iicbus/iiconf.h>
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#include "iicbus_if.h"
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#include "gpio_if.h"
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#include <arm/samsung/exynos/chrome_ec.h>
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struct ec_softc {
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device_t dev;
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int have_arbitrator;
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pcell_t our_gpio;
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pcell_t ec_gpio;
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};
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struct ec_softc *ec_sc;
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/*
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* bus_claim, bus_release
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* both functions used for bus arbitration
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* in multi-master mode
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*/
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static int
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bus_claim(struct ec_softc *sc)
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{
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device_t gpio_dev;
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int status;
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if (sc->our_gpio == 0 || sc->ec_gpio == 0) {
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device_printf(sc->dev, "i2c arbitrator is not configured\n");
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return (1);
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}
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gpio_dev = devclass_get_device(devclass_find("gpio"), 0);
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if (gpio_dev == NULL) {
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device_printf(sc->dev, "cant find gpio_dev\n");
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return (1);
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}
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/* Say we want the bus */
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GPIO_PIN_SET(gpio_dev, sc->our_gpio, GPIO_PIN_LOW);
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/* TODO: insert a delay to allow EC to react. */
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/* Check EC decision */
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GPIO_PIN_GET(gpio_dev, sc->ec_gpio, &status);
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if (status == 1) {
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/* Okay. We have bus */
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return (0);
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}
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/* EC is master */
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return (-1);
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}
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static int
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bus_release(struct ec_softc *sc)
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{
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device_t gpio_dev;
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if (sc->our_gpio == 0 || sc->ec_gpio == 0) {
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device_printf(sc->dev, "i2c arbitrator is not configured\n");
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return (1);
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}
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gpio_dev = devclass_get_device(devclass_find("gpio"), 0);
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if (gpio_dev == NULL) {
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device_printf(sc->dev, "cant find gpio_dev\n");
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return (1);
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}
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GPIO_PIN_SET(gpio_dev, sc->our_gpio, GPIO_PIN_HIGH);
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return (0);
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}
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static int
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ec_probe(device_t dev)
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{
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device_set_desc(dev, "Chromebook Embedded Controller");
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return (BUS_PROBE_DEFAULT);
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}
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static int
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fill_checksum(uint8_t *data_out, int len)
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{
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int res;
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int i;
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res = 0;
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for (i = 0; i < len; i++) {
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res += data_out[i];
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}
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data_out[len] = (res & 0xff);
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return (0);
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}
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int
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ec_command(uint8_t cmd, uint8_t *dout, uint8_t dout_len,
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uint8_t *dinp, uint8_t dinp_len)
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{
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struct ec_softc *sc;
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uint8_t *msg_dout;
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uint8_t *msg_dinp;
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int ret;
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int i;
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msg_dout = malloc(dout_len + 4, M_DEVBUF, M_NOWAIT);
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msg_dinp = malloc(dinp_len + 3, M_DEVBUF, M_NOWAIT);
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if (ec_sc == NULL)
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return (-1);
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sc = ec_sc;
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msg_dout[0] = EC_CMD_VERSION0;
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msg_dout[1] = cmd;
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msg_dout[2] = dout_len;
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for (i = 0; i < dout_len; i++) {
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msg_dout[i + 3] = dout[i];
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}
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fill_checksum(msg_dout, dout_len + 3);
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struct iic_msg msgs[] = {
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{ 0x1e, IIC_M_WR, dout_len + 4, msg_dout, },
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{ 0x1e, IIC_M_RD, dinp_len + 3, msg_dinp, },
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};
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ret = iicbus_transfer(sc->dev, msgs, 2);
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if (ret != 0) {
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device_printf(sc->dev, "i2c transfer returned %d\n", ret);
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free(msg_dout, M_DEVBUF);
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free(msg_dinp, M_DEVBUF);
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return (-1);
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}
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for (i = 0; i < dinp_len; i++) {
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dinp[i] = msg_dinp[i + 2];
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}
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free(msg_dout, M_DEVBUF);
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free(msg_dinp, M_DEVBUF);
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return (0);
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}
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int ec_hello(void)
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{
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uint8_t data_in[4];
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uint8_t data_out[4];
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data_in[0] = 0x40;
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data_in[1] = 0x30;
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data_in[2] = 0x20;
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data_in[3] = 0x10;
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ec_command(EC_CMD_HELLO, data_in, 4,
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data_out, 4);
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return (0);
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}
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static void
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configure_i2c_arbitrator(struct ec_softc *sc)
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{
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phandle_t arbitrator;
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/* TODO: look for compatible entry instead of hard-coded path */
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arbitrator = OF_finddevice("/i2c-arbitrator");
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if (arbitrator > 0 &&
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OF_hasprop(arbitrator, "freebsd,our-gpio") &&
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OF_hasprop(arbitrator, "freebsd,ec-gpio")) {
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sc->have_arbitrator = 1;
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OF_getencprop(arbitrator, "freebsd,our-gpio",
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&sc->our_gpio, sizeof(sc->our_gpio));
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OF_getencprop(arbitrator, "freebsd,ec-gpio",
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&sc->ec_gpio, sizeof(sc->ec_gpio));
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} else {
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sc->have_arbitrator = 0;
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sc->our_gpio = 0;
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sc->ec_gpio = 0;
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}
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}
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static int
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ec_attach(device_t dev)
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{
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struct ec_softc *sc;
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sc = device_get_softc(dev);
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sc->dev = dev;
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ec_sc = sc;
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configure_i2c_arbitrator(sc);
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/*
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* Claim the bus.
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*
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* We don't know cases when EC is master,
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* so hold the bus forever for us.
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*
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*/
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if (sc->have_arbitrator && bus_claim(sc) != 0) {
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return (ENXIO);
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}
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return (0);
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}
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static int
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ec_detach(device_t dev)
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{
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struct ec_softc *sc;
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sc = device_get_softc(dev);
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if (sc->have_arbitrator) {
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bus_release(sc);
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}
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return (0);
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}
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static device_method_t ec_methods[] = {
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DEVMETHOD(device_probe, ec_probe),
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DEVMETHOD(device_attach, ec_attach),
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DEVMETHOD(device_detach, ec_detach),
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{ 0, 0 }
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};
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static driver_t ec_driver = {
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"chrome_ec",
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ec_methods,
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sizeof(struct ec_softc),
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};
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static devclass_t ec_devclass;
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DRIVER_MODULE(chrome_ec, iicbus, ec_driver, ec_devclass, 0, 0);
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MODULE_VERSION(chrome_ec, 1);
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MODULE_DEPEND(chrome_ec, iicbus, 1, 1, 1);
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