/*
 * oFono - Open Source Telephony
 * Copyright (C) 2014  Philip Paeps
 *
 * SPDX-License-Identifier: GPL-2.0-only
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <errno.h>
#include <stdlib.h>
#include <stdbool.h>
#include <unistd.h>

#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <linux/tty.h>
#include <linux/gsmmux.h>
#include <ell/ell.h>
#include <gatchat.h>
#include <gattty.h>
#include <gatmux.h>

#define OFONO_API_SUBJECT_TO_CHANGE
#include <ofono.h>
#include <ofono/plugin.h>
#include <ofono/modem.h>
#include <ofono/devinfo.h>
#include <ofono/netreg.h>
#include <ofono/sim.h>
#include <ofono/sms.h>
#include <ofono/phonebook.h>
#include <ofono/voicecall.h>
#include <ofono/call-volume.h>
#include <ofono/gprs.h>
#include <ofono/gprs-context.h>
#include <ofono/log.h>
#include <ofono/dbus.h>
#include <ofono/radio-settings.h>

#include <gdbus/gdbus.h>

#include <drivers/atmodem/atutil.h>
#include <drivers/atmodem/vendor.h>

static const char *cfun_prefix[] = { "+CFUN:", NULL };
static const char *cpin_prefix[] = { "+CPIN:", NULL };
static const char *cbc_prefix[] = { "+CBC:", NULL };
static const char *qinistat_prefix[] = { "+QINISTAT:", NULL };
static const char *cgmm_prefix[] = { "UC15", "Quectel_M95", "EG916Q-GL", "Quectel_MC60",
					"EC21", "EC200", NULL };
static const char *none_prefix[] = { NULL };

static const uint8_t gsm0710_terminate[] = {
	0xf9, /* open flag */
	0x03, /* channel 0 */
	0xef, /* UIH frame */
	0x05, /* 2 data bytes */
	0xc3, /* terminate 1 */
	0x01, /* terminate 2 */
	0xf2, /* crc */
	0xf9, /* close flag */
};

enum quectel_model {
	QUECTEL_UNKNOWN,
	QUECTEL_UC15,
	QUECTEL_M95,
	QUECTEL_EG916Q,
	QUECTEL_MC60,
	QUECTEL_EC21,
	QUECTEL_EC200,
};

struct quectel_data {
	GAtChat *modem;
	GAtChat *aux;
	enum ofono_vendor vendor;
	enum quectel_model model;
	struct at_util_sim_state_query *sim_state_query;
	unsigned int sim_watch;
	bool sim_locked;
	bool sim_ready;

	/* used by quectel uart driver */
	GIOChannel *device;
	GAtChat *uart;
	GAtMux *mux;
	int mux_ready_count;
	int initial_ldisc;
	struct l_gpio_writer *gpio;
	struct l_timeout *init_timeout;
	struct l_timeout *gpio_timeout;
	size_t init_count;
	guint init_cmd;
};

struct dbus_hw {
	DBusMessage *msg;
	struct ofono_modem *modem;
	int32_t charge_status;
	int32_t charge_level;
	int32_t voltage;
};

enum quectel_power_event {
	LOW_POWER_DOWN    = -2,
	LOW_WARNING       = -1,
	NORMAL_POWER_DOWN =  0,
	HIGH_WARNING      =  1,
	HIGH_POWER_DOWN   =  2,
};

static const char dbus_hw_interface[] = OFONO_SERVICE ".quectel.Hardware";

static ofono_bool_t quectel_model_supports_lte(enum quectel_model model)
{
	switch (model) {
	case QUECTEL_EC21:
	case QUECTEL_EC200:
	case QUECTEL_EG916Q:
		return TRUE;
	default:
		return FALSE;
	}
}

static ofono_bool_t has_serial_connection(struct ofono_modem *modem)
{

	if (ofono_modem_get_string(modem, "Device"))
		return TRUE;

	return FALSE;
}

static void quectel_debug(const char *str, void *user_data)
{
	const char *prefix = user_data;

	ofono_info("%s%s", prefix, str);
}

static int quectel_probe_gpio(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);
	struct l_gpio_chip *gpiochip;
	uint32_t offset;
	const char *chip_name, *offset_str;
	uint32_t value = 0;

	DBG("%p", modem);

	chip_name = ofono_modem_get_string(modem, "GpioChip");
	if (!chip_name)
		return 0;

	offset_str = ofono_modem_get_string(modem, "GpioOffset");
	if (!offset_str)
		return -EINVAL;

	offset = strtoul(offset_str, NULL, 0);
	if (!offset)
		return -EINVAL;

	gpiochip = l_gpio_chip_new(chip_name);
	if (!gpiochip)
		return -ENODEV;

	data->gpio = l_gpio_writer_new(gpiochip, "ofono", 1, &offset,
						&value);

	l_gpio_chip_free(gpiochip);

	if (!data->gpio)
		return -EIO;

	return 0;
}

static int quectel_probe(struct ofono_modem *modem)
{
	struct quectel_data *data;

	DBG("%p", modem);

	data = l_new(struct quectel_data, 1);

	ofono_modem_set_data(modem, data);

	return quectel_probe_gpio(modem);
}

static void quectel_remove(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);

	DBG("%p", modem);

	ofono_modem_set_data(modem, NULL);
	l_timeout_remove(data->init_timeout);
	l_timeout_remove(data->gpio_timeout);
	l_gpio_writer_free(data->gpio);
	at_util_sim_state_query_free(data->sim_state_query);
	g_at_chat_unref(data->aux);
	g_at_chat_unref(data->modem);
	g_at_chat_unref(data->uart);
	g_at_mux_unref(data->mux);

	if (data->device)
		g_io_channel_unref(data->device);

	l_free(data);
}

static void close_mux(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);

	DBG("%p", modem);

	g_io_channel_unref(data->device);
	data->device = NULL;

	g_at_mux_unref(data->mux);
	data->mux = NULL;
}

static void close_ngsm(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);
	int fd;

	DBG("%p", modem);

	if (!data->device)
		return;

	fd = g_io_channel_unix_get_fd(data->device);

	/* restore initial tty line discipline */
	if (ioctl(fd, TIOCSETD, &data->initial_ldisc) < 0)
		ofono_warn("Failed to restore line discipline");
}

static void gpio_power_off_cb(struct l_timeout *timeout, void *user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);
	const uint32_t gpio_value = 0;

	l_timeout_remove(timeout);
	data->gpio_timeout = NULL;
	l_gpio_writer_set(data->gpio, 1, &gpio_value);
	ofono_modem_set_powered(modem, FALSE);
}

static void close_serial(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);
	uint32_t gpio_value = 1;

	DBG("%p", modem);

	at_util_sim_state_query_free(data->sim_state_query);
	data->sim_state_query = NULL;

	g_at_chat_unref(data->aux);
	data->aux = NULL;

	g_at_chat_unref(data->modem);
	data->modem = NULL;

	g_at_chat_unref(data->uart);
	data->uart = NULL;

	if (data->mux)
		close_mux(modem);
	else
		close_ngsm(modem);

	if (data->gpio) {
		if (ofono_modem_get_boolean(modem, "GpioLevel")) {
			gpio_value = 0;
			l_gpio_writer_set(data->gpio, 1, &gpio_value);
		} else {
			l_gpio_writer_set(data->gpio, 1, &gpio_value);
			l_timeout_remove(data->gpio_timeout);
			data->gpio_timeout = l_timeout_create_ms(750,
							gpio_power_off_cb,
							modem, NULL);
			return;
		}
	}

	ofono_modem_set_powered(modem, FALSE);
}

static void dbus_hw_reply_properties(struct dbus_hw *hw)
{
	struct quectel_data *data = ofono_modem_get_data(hw->modem);
	DBusMessage *reply;
	DBusMessageIter dbus_iter;
	DBusMessageIter dbus_dict;

	DBG("%p", hw->modem);

	reply = dbus_message_new_method_return(hw->msg);
	dbus_message_iter_init_append(reply, &dbus_iter);
	dbus_message_iter_open_container(&dbus_iter, DBUS_TYPE_ARRAY,
			OFONO_PROPERTIES_ARRAY_SIGNATURE,
			&dbus_dict);

	/*
	 * the charge status/level received from m95 and mc60 are invalid so
	 * only return those for the UC15 modem.
	 */
	if (data->model == QUECTEL_UC15) {
		ofono_dbus_dict_append(&dbus_dict, "ChargeStatus",
					DBUS_TYPE_INT32, &hw->charge_status);

		ofono_dbus_dict_append(&dbus_dict, "ChargeLevel",
					DBUS_TYPE_INT32, &hw->charge_level);
	}

	ofono_dbus_dict_append(&dbus_dict, "Voltage", DBUS_TYPE_INT32,
				&hw->voltage);

	dbus_message_iter_close_container(&dbus_iter, &dbus_dict);

	__ofono_dbus_pending_reply(&hw->msg, reply);
}

static void cbc_cb(gboolean ok, GAtResult *result, gpointer user_data)
{
	struct dbus_hw *hw = user_data;
	GAtResultIter iter;

	DBG("%p", hw->modem);

	if (!hw->msg)
		return;

	if (!ok)
		goto error;

	g_at_result_iter_init(&iter, result);

	if (!g_at_result_iter_next(&iter, "+CBC:"))
		goto error;

	/* the returned charge status is valid only for uc15 */
	if (!g_at_result_iter_next_number(&iter, &hw->charge_status))
		goto error;

	/* the returned charge level is valid only for uc15 */
	if (!g_at_result_iter_next_number(&iter, &hw->charge_level))
		goto error;

	/* now comes the millivolts */
	if (!g_at_result_iter_next_number(&iter, &hw->voltage))
		goto error;

	dbus_hw_reply_properties(hw);

	return;

error:
	__ofono_dbus_pending_reply(&hw->msg, __ofono_error_failed(hw->msg));
}

static DBusMessage *dbus_hw_get_properties(DBusConnection *conn,
						DBusMessage *msg,
						void *user_data)
{
	struct dbus_hw *hw = user_data;
	struct quectel_data *data = ofono_modem_get_data(hw->modem);

	DBG("%p", hw->modem);

	if (hw->msg != NULL)
		return __ofono_error_busy(msg);

	if (!g_at_chat_send(data->aux, "AT+CBC", cbc_prefix, cbc_cb, hw, NULL))
		return __ofono_error_failed(msg);

	hw->msg = dbus_message_ref(msg);

	return NULL;
}

static void voltage_handle(struct ofono_modem *modem,
				enum quectel_power_event event)
{
	DBusConnection *conn = ofono_dbus_get_connection();
	DBusMessage *signal;
	DBusMessageIter iter;
	const char *path = ofono_modem_get_path(modem);
	const char *name;
	const char *reason;
	bool close;

	DBG("%p", modem);

	switch (event) {
	case LOW_POWER_DOWN:
		close = true;
		name = "PowerDown";
		reason = "voltagelow";
		break;
	case LOW_WARNING:
		close = false;
		name = "PowerWarning";
		reason = "voltagelow";
		break;
	case NORMAL_POWER_DOWN:
		close = true;
		name = "PowerDown";
		reason = "normal";
		break;
	case HIGH_WARNING:
		close = false;
		name = "PowerWarning";
		reason = "voltagehigh";
		break;
	case HIGH_POWER_DOWN:
		close = true;
		name = "PowerDown";
		reason = "voltagehigh";
		break;
	default:
		return;
	}

	signal = dbus_message_new_signal(path, dbus_hw_interface, name);
	if (signal) {
		dbus_message_iter_init_append(signal, &iter);
		dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING,
						&reason);
		g_dbus_send_message(conn, signal);
	}

	if (close)
		close_serial(modem);
}

static void qind_notify(GAtResult *result, void *user_data)
{
	struct dbus_hw *hw = user_data;
	GAtResultIter iter;
	enum quectel_power_event event;
	const char *type;

	DBG("%p", hw->modem);

	g_at_result_iter_init(&iter, result);
	g_at_result_iter_next(&iter, "+QIND:");

	if (!g_at_result_iter_next_string(&iter, &type))
		return;

	if (g_strcmp0("vbatt", type)) {
		if (!g_at_result_iter_next_number(&iter, &event))
			return;

		voltage_handle(hw->modem, event);
	}
}

static void power_notify(GAtResult *result, void *user_data)
{
	struct dbus_hw *hw = user_data;
	GAtResultIter iter;
	const char *event;

	DBG("%p", hw->modem);

	g_at_result_iter_init(&iter, result);
	g_at_result_iter_next(&iter, NULL);

	if (!g_at_result_iter_next_unquoted_string(&iter, &event))
		return;

	DBG("event: %s", event);

	if (g_strcmp0(event, "UNDER_VOLTAGE POWER DOWN") == 0)
		voltage_handle(hw->modem, LOW_POWER_DOWN);
	else if (g_strcmp0(event, "UNDER_VOLTAGE WARNING") == 0)
		voltage_handle(hw->modem, LOW_WARNING);
	else if (g_strcmp0(event, "NORMAL POWER DOWN") == 0)
		voltage_handle(hw->modem, NORMAL_POWER_DOWN);
	else if (g_strcmp0(event, "OVER_VOLTAGE WARNING") == 0)
		voltage_handle(hw->modem, HIGH_WARNING);
	else if (g_strcmp0(event, "OVER_VOLTAGE POWER DOWN") == 0)
		voltage_handle(hw->modem, HIGH_POWER_DOWN);
}

static const GDBusMethodTable dbus_hw_methods[] = {
	{ GDBUS_ASYNC_METHOD("GetProperties",
				NULL, GDBUS_ARGS({ "properties", "a{sv}" }),
				dbus_hw_get_properties) },
	{}
};

static const GDBusSignalTable dbus_hw_signals[] = {
	{ GDBUS_SIGNAL("PowerDown",
			GDBUS_ARGS({ "reason", "s" })) },
	{ GDBUS_SIGNAL("PowerWarning",
			GDBUS_ARGS({ "reason", "s" })) },
	{ }
};

static void dbus_hw_cleanup(void *data)
{
	struct dbus_hw *hw = data;

	DBG("%p", hw->modem);

	if (hw->msg)
		__ofono_dbus_pending_reply(&hw->msg,
					__ofono_error_canceled(hw->msg));

	l_free(hw);
}

static void dbus_hw_enable(struct ofono_modem *modem)
{
	DBusConnection *conn = ofono_dbus_get_connection();
	struct quectel_data *data = ofono_modem_get_data(modem);
	const char *path = ofono_modem_get_path(modem);
	struct dbus_hw *hw;

	DBG("%p", modem);

	hw = l_new(struct dbus_hw, 1);
	hw->modem = modem;

	if (!g_dbus_register_interface(conn, path, dbus_hw_interface,
					dbus_hw_methods, dbus_hw_signals, NULL,
					hw, dbus_hw_cleanup)) {
		ofono_error("Could not register %s interface under %s",
				dbus_hw_interface, path);
		l_free(hw);
		return;
	}

	g_at_chat_register(data->aux, "NORMAL POWER DOWN", power_notify, FALSE,
				hw, NULL);

	switch (data->model) {
	case QUECTEL_UC15:
	case QUECTEL_EC21:
	case QUECTEL_EC200:
		g_at_chat_register(data->aux, "+QIND",  qind_notify, FALSE, hw,
					NULL);
		break;
	case QUECTEL_M95:
	case QUECTEL_EG916Q:
	case QUECTEL_MC60:
		g_at_chat_register(data->aux, "OVER_VOLTAGE POWER DOWN",
					power_notify, FALSE, hw, NULL);
		g_at_chat_register(data->aux, "UNDER_VOLTAGE POWER DOWN",
					power_notify, FALSE, hw, NULL);
		g_at_chat_register(data->aux, "OVER_VOLTAGE WARNING",
					power_notify, FALSE, hw, NULL);
		g_at_chat_register(data->aux, "UNDER_VOLTAGE WARNING",
					power_notify, FALSE, hw, NULL);
		break;
	case QUECTEL_UNKNOWN:
		break;
	}

	ofono_modem_add_interface(modem, dbus_hw_interface);
}

static void qinistat_cb(gboolean ok, GAtResult *result, gpointer user_data)
{
	struct ofono_modem *modem = user_data;
	struct ofono_sim *sim = ofono_modem_get_sim(modem);
	struct quectel_data *data = ofono_modem_get_data(modem);
	GAtResultIter iter;
	int ready = 0;
	int status;

	DBG("%p", modem);

	g_at_result_iter_init(&iter, result);

	if (!g_at_result_iter_next(&iter, "+QINISTAT:"))
		return;

	if (!g_at_result_iter_next_number(&iter, &status))
		return;

	DBG("qinistat: %d", status);

	switch (data->model) {
	case QUECTEL_UC15:
	case QUECTEL_EC21:
	case QUECTEL_EG916Q:
		/* UC15 uses a bitmap of 1 + 2 + 4 = 7 */
		ready = 7;
		break;
	case QUECTEL_EC200:
		/*
		 * EC200T doesn't indicate that the Phonebook initialization
		 * of some SIM cards is completed (==4) when AT+CFUN=4,
		 * that's why 1 + 2 = 3
		 */
		ready = 3;
		if ((status & ready) == ready)
			ready = status;
		break;
	case QUECTEL_M95:
	case QUECTEL_MC60:
		/* M95 and MC60 uses a counter to 3 */
		ready = 3;
		break;
	case QUECTEL_UNKNOWN:
		ready = 0;
		break;
	}

	if (status != ready) {
		l_timeout_modify_ms(data->init_timeout, 500);
		return;
	}

	l_timeout_remove(data->init_timeout);
	data->init_timeout = NULL;

	if (data->sim_locked) {
		ofono_sim_initialized_notify(sim);
		return;
	}

	data->sim_ready = true;

	if (quectel_model_supports_lte(data->model))
		ofono_modem_set_capabilities(modem, OFONO_MODEM_CAPABILITY_LTE);

	ofono_modem_set_powered(modem, TRUE);
}

static void init_timer_cb(struct l_timeout *timeout, void *user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);

	DBG("%p", modem);

	g_at_chat_send(data->aux, "AT+QINISTAT", qinistat_prefix, qinistat_cb,
			modem, NULL);
}

static void sim_watch_cb(GAtResult *result, void *user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);
	GAtResultIter iter;
	const char *cpin;

	DBG("%p", modem);

	g_at_result_iter_init(&iter, result);

	if (!g_at_result_iter_next(&iter, "+CPIN:"))
		return;

	g_at_result_iter_next_unquoted_string(&iter, &cpin);

	if (g_strcmp0(cpin, "READY") != 0)
		return;

	g_at_chat_unregister(data->aux, data->sim_watch);
	data->sim_watch = 0;

	data->init_timeout = l_timeout_create_ms(500, init_timer_cb, modem, NULL);
}

static void cpin_cb(gboolean ok, GAtResult *result, gpointer user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);
	const char *path = ofono_modem_get_path(modem);
	GAtResultIter iter;
	const char *cpin;

	DBG("%p", modem);

	if (!ok) {
		close_serial(modem);
		return;
	}

	g_at_result_iter_init(&iter, result);

	if (!g_at_result_iter_next(&iter, "+CPIN:")) {
		close_serial(modem);
		return;
	}

	g_at_result_iter_next_unquoted_string(&iter, &cpin);

	if (g_strcmp0(cpin, "READY") == 0) {
		data->init_timeout = l_timeout_create_ms(500, init_timer_cb,
								modem, NULL);
		return;
	}

	if (g_strcmp0(cpin, "SIM PIN") != 0) {
		close_serial(modem);
		return;
	}

	ofono_info("%s: sim locked", path);
	data->sim_locked = true;
	data->sim_watch = g_at_chat_register(data->aux, "+CPIN:",
						sim_watch_cb, FALSE,
						modem, NULL);
	ofono_modem_set_powered(modem, TRUE);
}

static void sim_state_cb(gboolean present, gpointer user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);
	const char *path = ofono_modem_get_path(modem);

	DBG("%p present %d", modem, present);

	at_util_sim_state_query_free(data->sim_state_query);
	data->sim_state_query = NULL;
	data->sim_locked = false;
	data->sim_ready = false;

	if (!present) {
		ofono_modem_set_powered(modem, TRUE);
		ofono_warn("%s: sim not present", path);
		return;
	}

	g_at_chat_send(data->aux, "AT+CPIN?", cpin_prefix, cpin_cb, modem,
			NULL);
}

static void cfun_cb(gboolean ok, GAtResult *result, gpointer user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);

	DBG("%p ok %d", modem, ok);

	if (!ok) {
		close_serial(modem);
		return;
	}

	dbus_hw_enable(modem);
	data->sim_state_query = at_util_sim_state_query_new(data->aux,
						2, 20, sim_state_cb, modem,
						NULL);
}

static void cfun_enable(gboolean ok, GAtResult *result, gpointer user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);

	DBG("%p ok %d", modem, ok);

	if (!ok) {
		close_serial(modem);
		return;
	}

	g_at_chat_send(data->aux, "AT+CFUN=4", none_prefix, cfun_cb, modem,
			NULL);
}

static void cfun_query(gboolean ok, GAtResult *result, gpointer user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);
	GAtResultIter iter;
	int cfun;

	DBG("%p ok %d", modem, ok);

	if (!ok) {
		close_serial(modem);
		return;
	}

	g_at_result_iter_init(&iter, result);

	if (g_at_result_iter_next(&iter, "+CFUN:") == FALSE) {
		close_serial(modem);
		return;
	}

	g_at_result_iter_next_number(&iter, &cfun);

	/*
	 * The modem firmware powers up in CFUN=1 but will respond to AT+CFUN=4
	 * with ERROR until some amount of time (which varies with temperature)
	 * passes.  Empirical evidence suggests that the firmware will report an
	 * unsolicited +CPIN: notification when it is ready to be useful.
	 *
	 * Work around this feature by only transitioning to CFUN=4 if the
	 * modem is not in CFUN=1 or until after we've received an unsolicited
	 * +CPIN: notification.
	 */
	if (cfun != 1)
		g_at_chat_send(data->aux, "AT+CFUN=4", none_prefix, cfun_enable,
				modem, NULL);
	else
		cfun_enable(TRUE, NULL, modem);
}

static void setup_aux(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);

	DBG("%p", modem);

	g_at_chat_set_slave(data->modem, data->aux);

	if (data->model == QUECTEL_EC21) {
		g_at_chat_send(data->aux, "ATE0; &C0; +CMEE=1", none_prefix,
				NULL, NULL, NULL);
		g_at_chat_send(data->aux, "AT+QURCCFG=\"urcport\",\"uart1\"", none_prefix,
				NULL, NULL, NULL);
	} else if (data->model == QUECTEL_EC200) {
		g_at_chat_send(data->aux, "ATE0; &C0; +CMEE=1", none_prefix,
				NULL, NULL, NULL);
		g_at_chat_send(data->aux, "AT+QCFG=\"servicedomain\",2", none_prefix,
				NULL, NULL, NULL);
	} else
		g_at_chat_send(data->aux, "ATE0; &C0; +CMEE=1; +QIURC=0",
				none_prefix, NULL, NULL, NULL);

	g_at_chat_send(data->aux, "AT+CFUN?", cfun_prefix, cfun_query, modem,
			NULL);
}

static void cgmm_cb(int ok, GAtResult *result, void *user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);
	const char *model;

	DBG("%p ok %d", modem, ok);

	if (!at_util_parse_attr(result, "", &model)) {
		ofono_error("Failed to query modem model");
		close_serial(modem);
		return;
	}

	if (strcmp(model, "UC15") == 0) {
		DBG("%p model UC15", modem);
		data->vendor = OFONO_VENDOR_QUECTEL;
		data->model = QUECTEL_UC15;
	} else if (strcmp(model, "Quectel_M95") == 0) {
		DBG("%p model M95", modem);
		data->vendor = OFONO_VENDOR_QUECTEL_SERIAL;
		data->model = QUECTEL_M95;
	} else if (strcmp(model, "EG916Q-GL") == 0) {
		DBG("%p model EG916Q-GL", modem);
		data->vendor = OFONO_VENDOR_QUECTEL_EG91X;
		data->model = QUECTEL_EG916Q;
	} else if (strcmp(model, "Quectel_MC60") == 0) {
		DBG("%p model MC60", modem);
		data->vendor = OFONO_VENDOR_QUECTEL_SERIAL;
		data->model = QUECTEL_MC60;
	} else if (strcmp(model, "EC21") == 0) {
		DBG("%p model EC21", modem);
		data->vendor = OFONO_VENDOR_QUECTEL_EC2X;
		data->model = QUECTEL_EC21;
	} else if (strstr(model, "EC200")) {
		DBG("%p model %s", modem, model);
		data->vendor = OFONO_VENDOR_QUECTEL_EC2X;
		data->model = QUECTEL_EC200;
	} else {
		ofono_warn("%p unknown model: '%s'", modem, model);
		data->vendor = OFONO_VENDOR_QUECTEL;
		data->model = QUECTEL_UNKNOWN;
	}

	setup_aux(modem);
}

static void identify_model(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);

	DBG("%p", modem);

	g_at_chat_send(data->aux, "AT+CGMM", cgmm_prefix, cgmm_cb, modem,
			NULL);
}

static int open_ttys(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);

	DBG("%p", modem);

	data->modem = at_util_open_device(modem, "Modem", quectel_debug,
						"Modem: ", NULL);
	if (data->modem == NULL)
		return -EINVAL;

	data->aux = at_util_open_device(modem, "Aux", quectel_debug, "Aux: ",
					NULL);
	if (data->aux == NULL) {
		g_at_chat_unref(data->modem);
		data->modem = NULL;
		return -EIO;
	}

	identify_model(modem);

	return -EINPROGRESS;
}

static GAtChat *create_chat(struct ofono_modem *modem, char *debug)
{
	struct quectel_data *data = ofono_modem_get_data(modem);
	GIOChannel *channel;
	GAtSyntax *syntax;
	GAtChat *chat;

	DBG("%p", modem);

	channel = g_at_mux_create_channel(data->mux);
	if (channel == NULL)
		return NULL;

	syntax = g_at_syntax_new_gsmv1();
	chat = g_at_chat_new(channel, syntax);
	g_at_syntax_unref(syntax);
	g_io_channel_unref(channel);

	if (chat == NULL)
		return NULL;

	if (getenv("OFONO_AT_DEBUG"))
		g_at_chat_set_debug(chat, quectel_debug, debug);

	return chat;
}

static void cmux_gatmux(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);

	DBG("%p", modem);

	data->mux = g_at_mux_new_gsm0710_basic(data->device, 127);
	if (data->mux == NULL) {
		ofono_error("failed to create gsm0710 mux");
		close_serial(modem);
		return;
	}

	if (getenv("OFONO_MUX_DEBUG"))
		g_at_mux_set_debug(data->mux, quectel_debug, "Mux: ");

	g_at_mux_start(data->mux);

	data->modem = create_chat(modem, "Modem: ");
	if (!data->modem) {
		ofono_error("failed to create modem channel");
		close_serial(modem);
		return;
	}

	data->aux = create_chat(modem, "Aux: ");
	if (!data->aux) {
		ofono_error("failed to create aux channel");
		close_serial(modem);
		return;
	}

	identify_model(modem);
}

static void mux_ready_cb(struct l_timeout *timeout, void *user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);
	struct stat st;
	int ret;

	DBG("%p", modem);

	/* check if the last (and thus all) virtual gsm tty's are created */
	ret = stat(ofono_modem_get_string(modem, "Modem"), &st);
	if (ret < 0) {
		if (data->mux_ready_count++ < 5) {
			/* not ready yet; try again in 100 ms*/
			l_timeout_modify_ms(timeout, 100);
			return;
		}

		/* not ready after 500 ms; bail out */
		close_serial(modem);
		return;
	}

	/* virtual gsm tty's are ready */
	l_timeout_remove(timeout);

	if (open_ttys(modem) != -EINPROGRESS)
		close_serial(modem);

	g_at_chat_set_slave(data->uart, data->modem);
}

static void cmux_ngsm(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);
	struct gsm_config gsm_config;
	int ldisc = N_GSM0710;
	int fd;

	DBG("%p", modem);

	fd = g_io_channel_unix_get_fd(data->device);

	/* get initial line discipline to restore after use */
	if (ioctl(fd, TIOCGETD, &data->initial_ldisc) < 0) {
		ofono_error("Failed to get current line discipline: %s",
				strerror(errno));
		close_serial(modem);
		return;
	}

	/* enable gsm 0710 multiplexing line discipline */
	if (ioctl(fd, TIOCSETD, &ldisc) < 0) {
		ofono_error("Failed to set multiplexer line discipline: %s",
				strerror(errno));
		close_serial(modem);
		return;
	}

	/* get n_gsm configuration */
	if (ioctl(fd, GSMIOC_GETCONF, &gsm_config) < 0) {
		ofono_error("Failed to get gsm config: %s", strerror(errno));
		close_serial(modem);
		return;
	}

	gsm_config.initiator = 1;     /* cpu side is initiating multiplexing */
	gsm_config.encapsulation = 0; /* basic transparency encoding */
	gsm_config.mru = 127;         /* 127 bytes rx mtu */
	gsm_config.mtu = 127;         /* 127 bytes tx mtu */
	gsm_config.t1 = 10;           /* 100 ms ack timer */
	gsm_config.n2 = 3;            /* 3 retries */
	gsm_config.t2 = 30;           /* 300 ms response timer */
	gsm_config.t3 = 10;           /* 100 ms wake up response timer */
	gsm_config.i = 1;             /* subset */

	/* set the new configuration */
	if (ioctl(fd, GSMIOC_SETCONF, &gsm_config) < 0) {
		ofono_error("Failed to set gsm config: %s", strerror(errno));
		close_serial(modem);
		return;
	}

	/*
	 * the kernel does not yet support mapping the underlying serial device
	 * to its virtual gsm ttys, so hard-code gsmtty1 gsmtty2 for now
	 */
	ofono_modem_set_string(modem, "Modem", "/dev/gsmtty1");
	ofono_modem_set_string(modem, "Aux", "/dev/gsmtty2");

	/* wait for gsmtty devices to appear */
	if (!l_timeout_create_ms(100, mux_ready_cb, modem, NULL)) {
		close_serial(modem);
		return;
	}
}

static void cmux_cb(gboolean ok, GAtResult *result, gpointer user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);
	const char *mux = ofono_modem_get_string(modem, "Mux");

	DBG("%p", modem);

	g_at_chat_unref(data->uart);
	data->uart = NULL;

	if (!ok) {
		close_serial(modem);
		return;
	}

	if (!mux)
		mux = "internal";

	if (strcmp(mux, "n_gsm") == 0) {
		cmux_ngsm(modem);
		return;
	}

	if (strcmp(mux, "internal") == 0) {
		cmux_gatmux(modem);
		return;
	}

	ofono_error("unsupported mux setting: '%s'", mux);
	close_serial(modem);
}

static void ate_cb(int ok, GAtResult *result, void *user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);

	DBG("%p", modem);

	g_at_chat_send(data->uart, "AT+CMUX=0,0,5,127,10,3,30,10,2", NULL,
		cmux_cb, modem, NULL);
}

static void init_cmd_cb(gboolean ok, GAtResult *result, void *user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);
	const char *rts_cts;

	DBG("%p", modem);

	if (!ok)
		return;

	rts_cts = ofono_modem_get_string(modem, "RtsCts");

	if (strcmp(rts_cts, "on") == 0)
		g_at_chat_send(data->uart, "AT+IFC=2,2; E0", none_prefix,
				ate_cb, modem, NULL);
	else
		g_at_chat_send(data->uart, "ATE0", none_prefix, ate_cb, modem,
				NULL);

	l_timeout_remove(data->init_timeout);
	data->init_timeout = NULL;
}

static void init_timeout_cb(struct l_timeout *timeout, void *user_data)
{
	struct ofono_modem *modem = user_data;
	struct quectel_data *data = ofono_modem_get_data(modem);

	DBG("%p", modem);

	if (data->init_count++ >= 30) {
		ofono_error("failed to init modem after 30 attempts");
		close_serial(modem);
		return;
	}

	g_at_chat_retry(data->uart, data->init_cmd);
	l_timeout_modify_ms(timeout, 500);
}

static void gpio_power_on_cb(struct l_timeout *timeout, void *user_data)
{
	struct quectel_data *data = user_data;
	const uint32_t gpio_value = 0;

	l_timeout_remove(timeout);
	data->gpio_timeout = NULL;
	l_gpio_writer_set(data->gpio, 1, &gpio_value);
}

static int open_serial(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);
	const uint32_t gpio_value = 1;
	const char *rts_cts;
	ssize_t written;
	int fd;

	DBG("%p", modem);

	rts_cts = ofono_modem_get_string(modem, "RtsCts");

	data->uart = at_util_open_device(modem, "Device", quectel_debug,
						"UART: ",
						"Baud", "115200",
						"Parity", "none",
						"StopBits", "1",
						"DataBits", "8",
						"XonXoff", "off",
						"Local", "on",
						"Read", "on",
						"RtsCts", rts_cts,
						NULL);
	if (data->uart == NULL)
		return -EINVAL;

	data->device = g_at_chat_get_channel(data->uart);
	g_io_channel_ref(data->device);

	/*
	 * terminate gsm 0710 multiplexing on the modem side to make sure it
	 * responds to plain AT commands
	 * */
	fd = g_io_channel_unix_get_fd(data->device);
	written = write(fd, gsm0710_terminate, sizeof(gsm0710_terminate));
	if (written != sizeof(gsm0710_terminate))
		ofono_warn("Failed to terminate gsm multiplexing");

	if (data->gpio && !l_gpio_writer_set(data->gpio, 1, &gpio_value)) {
		close_serial(modem);
		return -EIO;
	}

	if (data->gpio && !ofono_modem_get_boolean(modem, "GpioLevel"))
		data->gpio_timeout = l_timeout_create_ms(2100, gpio_power_on_cb,
							 data, NULL);

	/*
	 * there are three different power-up scenarios:
	 *
	 *  1) the gpio has just been toggled on, so the modem is not ready
	 *     until it prints RDY
	 *
	 *  2) the modem has been on for a while and ready to respond to
	 *     commands, so there will be no RDY notification
	 *
	 *  3) either of the previous to scenarious is the case, but the modem
	 *     UART is not configured to a fixed bitrate. In this case it needs
	 *     a few 'AT' bytes to detect the host UART bitrate, but the RDY is
	 *     lost.
	 *
	 * Handle all three cases by issuing a plain AT command. The modem
	 * answers with OK when it is ready. Create a timer to re-issue
	 * the AT command at regular intervals until the modem answers.
	 */
	data->init_count = 0;
	data->init_cmd = g_at_chat_send(data->uart, "AT", none_prefix,
					init_cmd_cb, modem, NULL);
	data->init_timeout = l_timeout_create_ms(500, init_timeout_cb, modem,
							NULL);

	return -EINPROGRESS;
}

static int quectel_enable(struct ofono_modem *modem)
{
	DBG("%p", modem);

	if (has_serial_connection(modem))
		return open_serial(modem);
	else
		return open_ttys(modem);
}

static void cfun_disable(gboolean ok, GAtResult *result, gpointer user_data)
{
	struct ofono_modem *modem = user_data;

	DBG("%p", modem);

	close_serial(modem);
}

static int quectel_disable(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);
	DBusConnection *conn = ofono_dbus_get_connection();
	const char *path = ofono_modem_get_path(modem);

	DBG("%p", modem);

	g_at_chat_cancel_all(data->modem);
	g_at_chat_unregister_all(data->modem);

	g_at_chat_cancel_all(data->aux);
	g_at_chat_unregister_all(data->aux);

	if (g_dbus_unregister_interface(conn, path, dbus_hw_interface))
		ofono_modem_remove_interface(modem, dbus_hw_interface);

	g_at_chat_send(data->aux, "AT+CFUN=0", cfun_prefix, cfun_disable, modem,
			NULL);

	return -EINPROGRESS;
}

static void set_online_cb(gboolean ok, GAtResult *result, gpointer user_data)
{
	struct cb_data *cbd = user_data;
	ofono_modem_online_cb_t cb = cbd->cb;
	struct ofono_error error;

	DBG("%p", user_data);

	decode_at_error(&error, g_at_result_final_response(result));
	cb(&error, cbd->data);
}

static void quectel_set_online(struct ofono_modem *modem, ofono_bool_t online,
				ofono_modem_online_cb_t cb, void *user_data)
{
	struct quectel_data *data = ofono_modem_get_data(modem);
	struct cb_data *cbd = cb_data_new(cb, user_data);
	char const *command = online ? "AT+CFUN=1" : "AT+CFUN=4";

	DBG("modem %p %s", modem, online ? "online" : "offline");

	if (g_at_chat_send(data->aux, command, cfun_prefix, set_online_cb, cbd,
				g_free) > 0)
		return;

	CALLBACK_WITH_FAILURE(cb, cbd->data);

	g_free(cbd);
}

static void quectel_pre_sim(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);
	struct ofono_sim *sim;

	DBG("%p", modem);

	ofono_devinfo_create(modem, data->vendor, "atmodem", data->aux);

	ofono_voicecall_create(modem, data->vendor, "atmodem", data->aux);
	sim = ofono_sim_create(modem, data->vendor, "atmodem", data->aux);

	if (data->sim_locked || data->sim_ready)
		ofono_sim_inserted_notify(sim, true);

	if (data->sim_ready)
		ofono_sim_initialized_notify(sim);
}

static void quectel_post_sim(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);
	struct ofono_gprs *gprs;
	struct ofono_gprs_context *gc;

	DBG("%p", modem);

	gprs = ofono_gprs_create(modem, data->vendor, "atmodem", data->aux);
	gc = ofono_gprs_context_create(modem, data->vendor, "atmodem",
					data->modem);

	if (gprs && gc)
		ofono_gprs_add_context(gprs, gc);

	ofono_sms_create(modem, data->vendor, "atmodem", data->aux);
	ofono_phonebook_create(modem, data->vendor, "atmodem", data->aux);
	ofono_call_volume_create(modem, data->vendor, "atmodem", data->aux);
	ofono_radio_settings_create(modem, 0, "quectelmodem", data->aux);

	if (data->model == QUECTEL_EC21 || data->model == QUECTEL_EC200)
		ofono_ussd_create(modem, data->vendor, "atmodem", data->aux);

	if (quectel_model_supports_lte(data->model))
		ofono_lte_create(modem, data->vendor, "atmodem", data->aux);
}

static void quectel_post_online(struct ofono_modem *modem)
{
	struct quectel_data *data = ofono_modem_get_data(modem);

	DBG("%p", modem);

	ofono_netreg_create(modem, data->vendor, "atmodem", data->aux);
}

static struct ofono_modem_driver quectel_driver = {
	.probe			= quectel_probe,
	.remove			= quectel_remove,
	.enable			= quectel_enable,
	.disable		= quectel_disable,
	.set_online		= quectel_set_online,
	.pre_sim		= quectel_pre_sim,
	.post_sim		= quectel_post_sim,
	.post_online		= quectel_post_online,
};

OFONO_MODEM_DRIVER_BUILTIN(quectel, &quectel_driver)
