simtech: implement GPS support with AT+CGPS

The new logic is available in a new 'MMSharedSimtech' interface which
is implemented both by the generic AT-based MMBroadbandModemSimtech
modem, and by a new QMI-based new MMBroadbandModemQmiSimtech.

Fixes https://gitlab.freedesktop.org/mobile-broadband/ModemManager/issues/112

6 files changed, 779 insertions, 21 deletions

diff --git a/plugins/simtech/mm-broadband-modem-qmi-simtech.c b/plugins/simtech/mm-broadband-modem-qmi-simtech.c
new file mode 100644
index 00000000..0b05e66d
--- /dev/null
+++ b/plugins/simtech/mm-broadband-modem-qmi-simtech.c
@@ -0,0 +1,91 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details:
+ *
+ * Copyright (C) 2019 Aleksander Morgado <aleksander@aleksander.es>
+ */
+
+#include <config.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <ctype.h>
+
+#include "ModemManager.h"
+#include "mm-log.h"
+#include "mm-errors-types.h"
+#include "mm-iface-modem-location.h"
+#include "mm-broadband-modem-qmi-simtech.h"
+#include "mm-shared-simtech.h"
+
+static void iface_modem_location_init (MMIfaceModemLocation *iface);
+static void shared_simtech_init       (MMSharedSimtech      *iface);
+
+static MMIfaceModemLocation *iface_modem_location_parent;
+
+G_DEFINE_TYPE_EXTENDED (MMBroadbandModemQmiSimtech, mm_broadband_modem_qmi_simtech, MM_TYPE_BROADBAND_MODEM_QMI, 0,
+                        G_IMPLEMENT_INTERFACE (MM_TYPE_IFACE_MODEM_LOCATION, iface_modem_location_init)
+                        G_IMPLEMENT_INTERFACE (MM_TYPE_SHARED_SIMTECH, shared_simtech_init))
+
+/*****************************************************************************/
+
+MMBroadbandModemQmiSimtech *
+mm_broadband_modem_qmi_simtech_new (const gchar  *device,
+                                    const gchar **drivers,
+                                    const gchar  *plugin,
+                                    guint16       vendor_id,
+                                    guint16       product_id)
+{
+    return g_object_new (MM_TYPE_BROADBAND_MODEM_QMI_SIMTECH,
+                         MM_BASE_MODEM_DEVICE,     device,
+                         MM_BASE_MODEM_DRIVERS,    drivers,
+                         MM_BASE_MODEM_PLUGIN,     plugin,
+                         MM_BASE_MODEM_VENDOR_ID,  vendor_id,
+                         MM_BASE_MODEM_PRODUCT_ID, product_id,
+                         NULL);
+}
+
+static void
+mm_broadband_modem_qmi_simtech_init (MMBroadbandModemQmiSimtech *self)
+{
+}
+
+static void
+iface_modem_location_init (MMIfaceModemLocation *iface)
+{
+    iface_modem_location_parent = g_type_interface_peek_parent (iface);
+
+    iface->load_capabilities                 = mm_shared_simtech_location_load_capabilities;
+    iface->load_capabilities_finish          = mm_shared_simtech_location_load_capabilities_finish;
+    iface->enable_location_gathering         = mm_shared_simtech_enable_location_gathering;
+    iface->enable_location_gathering_finish  = mm_shared_simtech_enable_location_gathering_finish;
+    iface->disable_location_gathering        = mm_shared_simtech_disable_location_gathering;
+    iface->disable_location_gathering_finish = mm_shared_simtech_disable_location_gathering_finish;
+}
+
+static MMIfaceModemLocation *
+peek_parent_location_interface (MMSharedSimtech *self)
+{
+    return iface_modem_location_parent;
+}
+
+static void
+shared_simtech_init (MMSharedSimtech *iface)
+{
+    iface->peek_parent_location_interface = peek_parent_location_interface;
+}
+
+static void
+mm_broadband_modem_qmi_simtech_class_init (MMBroadbandModemQmiSimtechClass *klass)
+{
+}
diff --git a/plugins/simtech/mm-broadband-modem-qmi-simtech.h b/plugins/simtech/mm-broadband-modem-qmi-simtech.h
new file mode 100644
index 00000000..2f5b819b
--- /dev/null
+++ b/plugins/simtech/mm-broadband-modem-qmi-simtech.h
@@ -0,0 +1,47 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details:
+ *
+ * Copyright (C) 2019 Aleksander Morgado <aleksander@aleksander.es>
+ */
+
+#ifndef MM_BROADBAND_MODEM_QMI_SIMTECH_QMI_H
+#define MM_BROADBAND_MODEM_QMI_SIMTECH_QMI_H
+
+#include "mm-broadband-modem-qmi.h"
+
+#define MM_TYPE_BROADBAND_MODEM_QMI_SIMTECH            (mm_broadband_modem_qmi_simtech_get_type ())
+#define MM_BROADBAND_MODEM_QMI_SIMTECH(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), MM_TYPE_BROADBAND_MODEM_QMI_SIMTECH, MMBroadbandModemQmiSimtech))
+#define MM_BROADBAND_MODEM_QMI_SIMTECH_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass),  MM_TYPE_BROADBAND_MODEM_QMI_SIMTECH, MMBroadbandModemQmiSimtechClass))
+#define MM_IS_BROADBAND_MODEM_QMI_SIMTECH(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), MM_TYPE_BROADBAND_MODEM_QMI_SIMTECH))
+#define MM_IS_BROADBAND_MODEM_QMI_SIMTECH_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass),  MM_TYPE_BROADBAND_MODEM_QMI_SIMTECH))
+#define MM_BROADBAND_MODEM_QMI_SIMTECH_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj),  MM_TYPE_BROADBAND_MODEM_QMI_SIMTECH, MMBroadbandModemQmiSimtechClass))
+
+typedef struct _MMBroadbandModemQmiSimtech MMBroadbandModemQmiSimtech;
+typedef struct _MMBroadbandModemQmiSimtechClass MMBroadbandModemQmiSimtechClass;
+
+struct _MMBroadbandModemQmiSimtech {
+    MMBroadbandModemQmi parent;
+};
+
+struct _MMBroadbandModemQmiSimtechClass{
+    MMBroadbandModemQmiClass parent;
+};
+
+GType mm_broadband_modem_qmi_simtech_get_type (void);
+
+MMBroadbandModemQmiSimtech *mm_broadband_modem_qmi_simtech_new (const gchar  *device,
+                                                                const gchar **drivers,
+                                                                const gchar  *plugin,
+                                                                guint16       vendor_id,
+                                                                guint16       product_id);
+
+#endif /* MM_BROADBAND_MODEM_QMI_SIMTECH_H */
diff --git a/plugins/simtech/mm-broadband-modem-simtech.c b/plugins/simtech/mm-broadband-modem-simtech.c
index b2001146..4294538d 100644
--- a/plugins/simtech/mm-broadband-modem-simtech.c
+++ b/plugins/simtech/mm-broadband-modem-simtech.c
@@ -32,17 +32,24 @@
 #include "mm-base-modem-at.h"
 #include "mm-iface-modem.h"
 #include "mm-iface-modem-3gpp.h"
+#include "mm-iface-modem-location.h"
+#include "mm-shared-simtech.h"
 #include "mm-broadband-modem-simtech.h"
 
-static void iface_modem_init (MMIfaceModem *iface);
-static void iface_modem_3gpp_init (MMIfaceModem3gpp *iface);
+static void iface_modem_init          (MMIfaceModem         *iface);
+static void iface_modem_3gpp_init     (MMIfaceModem3gpp     *iface);
+static void iface_modem_location_init (MMIfaceModemLocation *iface);
+static void shared_simtech_init       (MMSharedSimtech      *iface);
 
-static MMIfaceModem *iface_modem_parent;
-static MMIfaceModem3gpp *iface_modem_3gpp_parent;
+static MMIfaceModem         *iface_modem_parent;
+static MMIfaceModem3gpp     *iface_modem_3gpp_parent;
+static MMIfaceModemLocation *iface_modem_location_parent;
 
 G_DEFINE_TYPE_EXTENDED (MMBroadbandModemSimtech, mm_broadband_modem_simtech, MM_TYPE_BROADBAND_MODEM, 0,
                         G_IMPLEMENT_INTERFACE (MM_TYPE_IFACE_MODEM, iface_modem_init)
-                        G_IMPLEMENT_INTERFACE (MM_TYPE_IFACE_MODEM_3GPP, iface_modem_3gpp_init))
+                        G_IMPLEMENT_INTERFACE (MM_TYPE_IFACE_MODEM_3GPP, iface_modem_3gpp_init)
+                        G_IMPLEMENT_INTERFACE (MM_TYPE_IFACE_MODEM_LOCATION, iface_modem_location_init)
+                        G_IMPLEMENT_INTERFACE (MM_TYPE_SHARED_SIMTECH, shared_simtech_init))
 
 /*****************************************************************************/
 /* Setup/Cleanup unsolicited events (3GPP interface) */
@@ -828,6 +835,21 @@ mm_broadband_modem_simtech_init (MMBroadbandModemSimtech *self)
 }
 
 static void
+iface_modem_init (MMIfaceModem *iface)
+{
+    iface_modem_parent = g_type_interface_peek_parent (iface);
+
+    iface->load_access_technologies = load_access_technologies;
+    iface->load_access_technologies_finish = load_access_technologies_finish;
+    iface->load_supported_modes = load_supported_modes;
+    iface->load_supported_modes_finish = load_supported_modes_finish;
+    iface->load_current_modes = load_current_modes;
+    iface->load_current_modes_finish = load_current_modes_finish;
+    iface->set_current_modes = set_current_modes;
+    iface->set_current_modes_finish = set_current_modes_finish;
+}
+
+static void
 iface_modem_3gpp_init (MMIfaceModem3gpp *iface)
 {
     iface_modem_3gpp_parent = g_type_interface_peek_parent (iface);
@@ -844,18 +866,28 @@ iface_modem_3gpp_init (MMIfaceModem3gpp *iface)
 }
 
 static void
-iface_modem_init (MMIfaceModem *iface)
+iface_modem_location_init (MMIfaceModemLocation *iface)
 {
-    iface_modem_parent = g_type_interface_peek_parent (iface);
+    iface_modem_location_parent = g_type_interface_peek_parent (iface);
 
-    iface->load_access_technologies = load_access_technologies;
-    iface->load_access_technologies_finish = load_access_technologies_finish;
-    iface->load_supported_modes = load_supported_modes;
-    iface->load_supported_modes_finish = load_supported_modes_finish;
-    iface->load_current_modes = load_current_modes;
-    iface->load_current_modes_finish = load_current_modes_finish;
-    iface->set_current_modes = set_current_modes;
-    iface->set_current_modes_finish = set_current_modes_finish;
+    iface->load_capabilities                 = mm_shared_simtech_location_load_capabilities;
+    iface->load_capabilities_finish          = mm_shared_simtech_location_load_capabilities_finish;
+    iface->enable_location_gathering         = mm_shared_simtech_enable_location_gathering;
+    iface->enable_location_gathering_finish  = mm_shared_simtech_enable_location_gathering_finish;
+    iface->disable_location_gathering        = mm_shared_simtech_disable_location_gathering;
+    iface->disable_location_gathering_finish = mm_shared_simtech_disable_location_gathering_finish;
+}
+
+static MMIfaceModemLocation *
+peek_parent_location_interface (MMSharedSimtech *self)
+{
+    return iface_modem_location_parent;
+}
+
+static void
+shared_simtech_init (MMSharedSimtech *iface)
+{
+    iface->peek_parent_location_interface = peek_parent_location_interface;
 }
 
 static void
diff --git a/plugins/simtech/mm-plugin-simtech.c b/plugins/simtech/mm-plugin-simtech.c
index fb3a7950..79afeb54 100644
--- a/plugins/simtech/mm-plugin-simtech.c
+++ b/plugins/simtech/mm-plugin-simtech.c
@@ -26,7 +26,7 @@
 #include "mm-broadband-modem-simtech.h"
 
 #if defined WITH_QMI
-#include "mm-broadband-modem-qmi.h"
+#include "mm-broadband-modem-qmi-simtech.h"
 #endif
 
 G_DEFINE_TYPE (MMPluginSimtech, mm_plugin_simtech, MM_TYPE_PLUGIN)
@@ -48,11 +48,11 @@ create_modem (MMPlugin *self,
 #if defined WITH_QMI
     if (mm_port_probe_list_has_qmi_port (probes)) {
         mm_dbg ("QMI-powered SimTech modem found...");
-        return MM_BASE_MODEM (mm_broadband_modem_qmi_new (uid,
-                                                          drivers,
-                                                          mm_plugin_get_name (self),
-                                                          vendor,
-                                                          product));
+        return MM_BASE_MODEM (mm_broadband_modem_qmi_simtech_new (uid,
+                                                                  drivers,
+                                                                  mm_plugin_get_name (self),
+                                                                  vendor,
+                                                                  product));
     }
 #endif
 
diff --git a/plugins/simtech/mm-shared-simtech.c b/plugins/simtech/mm-shared-simtech.c
new file mode 100644
index 00000000..756713c5
--- /dev/null
+++ b/plugins/simtech/mm-shared-simtech.c
@@ -0,0 +1,515 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details:
+ *
+ * Copyright (C) 2019 Aleksander Morgado <aleksander@aleksander.es>
+ */
+
+#include <config.h>
+
+#include <glib-object.h>
+#include <gio/gio.h>
+
+#define _LIBMM_INSIDE_MM
+#include <libmm-glib.h>
+
+#include "mm-log.h"
+#include "mm-iface-modem.h"
+#include "mm-iface-modem-location.h"
+#include "mm-base-modem.h"
+#include "mm-base-modem-at.h"
+#include "mm-shared-simtech.h"
+
+/*****************************************************************************/
+/* Private data context */
+
+#define PRIVATE_TAG "shared-simtech-private-tag"
+static GQuark private_quark;
+
+typedef enum {
+    FEATURE_SUPPORT_UNKNOWN,
+    FEATURE_NOT_SUPPORTED,
+    FEATURE_SUPPORTED,
+} FeatureSupport;
+
+typedef struct {
+    /* location */
+    MMIfaceModemLocation  *iface_modem_location_parent;
+    MMModemLocationSource  supported_sources;
+    MMModemLocationSource  enabled_sources;
+    FeatureSupport         cgps_support;
+} Private;
+
+static Private *
+get_private (MMSharedSimtech *self)
+{
+    Private *priv;
+
+    if (G_UNLIKELY (!private_quark))
+        private_quark =  (g_quark_from_static_string (PRIVATE_TAG));
+
+    priv = g_object_get_qdata (G_OBJECT (self), private_quark);
+    if (!priv) {
+        priv = g_new0 (Private, 1);
+        priv->supported_sources = MM_MODEM_LOCATION_SOURCE_NONE;
+        priv->enabled_sources = MM_MODEM_LOCATION_SOURCE_NONE;
+        priv->cgps_support = FEATURE_SUPPORT_UNKNOWN;
+
+        /* Setup parent class' MMIfaceModemLocation */
+        g_assert (MM_SHARED_SIMTECH_GET_INTERFACE (self)->peek_parent_location_interface);
+        priv->iface_modem_location_parent = MM_SHARED_SIMTECH_GET_INTERFACE (self)->peek_parent_location_interface (self);
+
+        g_object_set_qdata_full (G_OBJECT (self), private_quark, priv, g_free);
+    }
+
+    return priv;
+}
+
+/*****************************************************************************/
+/* GPS trace received */
+
+static void
+trace_received (MMPortSerialGps      *port,
+                const gchar          *trace,
+                MMIfaceModemLocation *self)
+{
+    /* Helper to debug GPS location related issues. Don't depend on a real GPS
+     * fix for debugging, just use some random values to update */
+#if 0
+    if (g_str_has_prefix (trace, "$GPGGA")) {
+        GString *str;
+        GDateTime *now;
+
+        now = g_date_time_new_now_utc ();
+        str = g_string_new ("");
+        g_string_append_printf (str,
+                                "$GPGGA,%02u%02u%02u,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47",
+                                g_date_time_get_hour (now),
+                                g_date_time_get_minute (now),
+                                g_date_time_get_second (now));
+        mm_iface_modem_location_gps_update (self, str->str);
+        g_string_free (str, TRUE);
+        g_date_time_unref (now);
+        return;
+    }
+#endif
+
+    mm_iface_modem_location_gps_update (self, trace);
+}
+
+/*****************************************************************************/
+/* Location capabilities loading (Location interface) */
+
+MMModemLocationSource
+mm_shared_simtech_location_load_capabilities_finish (MMIfaceModemLocation  *self,
+                                                     GAsyncResult          *res,
+                                                     GError               **error)
+{
+    GError *inner_error = NULL;
+    gssize aux;
+
+    aux = g_task_propagate_int (G_TASK (res), &inner_error);
+    if (inner_error) {
+        g_propagate_error (error, inner_error);
+        return MM_MODEM_LOCATION_SOURCE_NONE;
+    }
+    return (MMModemLocationSource) aux;
+}
+
+static void probe_gps_features (GTask *task);
+
+static void
+cgps_test_ready (MMBaseModem  *self,
+                 GAsyncResult *res,
+                 GTask        *task)
+{
+    Private *priv;
+
+    priv = get_private (MM_SHARED_SIMTECH (self));
+
+    if (!mm_base_modem_at_command_finish (self, res, NULL))
+        priv->cgps_support = FEATURE_NOT_SUPPORTED;
+    else
+        priv->cgps_support = FEATURE_SUPPORTED;
+
+    probe_gps_features (task);
+}
+
+static void
+probe_gps_features (GTask *task)
+{
+    MMSharedSimtech       *self;
+    MMModemLocationSource  sources;
+    Private               *priv;
+
+    self = MM_SHARED_SIMTECH (g_task_get_source_object (task));
+    priv = get_private (self);
+
+    /* Need to check if CGPS supported... */
+    if (priv->cgps_support == FEATURE_SUPPORT_UNKNOWN) {
+        mm_base_modem_at_command (MM_BASE_MODEM (self), "+CGPS=?", 3, TRUE, (GAsyncReadyCallback) cgps_test_ready, task);
+        return;
+    }
+
+    /* All GPS features probed */
+
+    /* Recover parent sources */
+    sources = GPOINTER_TO_UINT (g_task_get_task_data (task));
+
+    if (priv->cgps_support == FEATURE_SUPPORTED) {
+        mm_dbg ("GPS commands supported: GPS capabilities enabled");
+
+        /* We only flag as supported by this implementation those sources not already
+         * supported by the parent implementation */
+        if (!(sources & MM_MODEM_LOCATION_SOURCE_GPS_NMEA))
+            priv->supported_sources |= MM_MODEM_LOCATION_SOURCE_GPS_NMEA;
+        if (!(sources & MM_MODEM_LOCATION_SOURCE_GPS_RAW))
+            priv->supported_sources |= MM_MODEM_LOCATION_SOURCE_GPS_RAW;
+        if (!(sources & MM_MODEM_LOCATION_SOURCE_GPS_UNMANAGED))
+            priv->supported_sources |= MM_MODEM_LOCATION_SOURCE_GPS_UNMANAGED;
+
+        sources |= priv->supported_sources;
+
+        /* Add handler for the NMEA traces in the GPS data port */
+        mm_port_serial_gps_add_trace_handler (mm_base_modem_peek_port_gps (MM_BASE_MODEM (self)),
+                                              (MMPortSerialGpsTraceFn)trace_received,
+                                              self,
+                                              NULL);
+    } else
+        mm_dbg ("No GPS command supported: no GPS capabilities");
+
+    g_task_return_int (task, (gssize) sources);
+    g_object_unref (task);
+}
+
+static void
+parent_load_capabilities_ready (MMIfaceModemLocation *self,
+                                GAsyncResult         *res,
+                                GTask                *task)
+{
+    MMModemLocationSource  sources;
+    GError                *error = NULL;
+    Private               *priv;
+
+    priv = get_private (MM_SHARED_SIMTECH (self));
+
+    sources = priv->iface_modem_location_parent->load_capabilities_finish (self, res, &error);
+    if (error) {
+        g_task_return_error (task, error);
+        g_object_unref (task);
+        return;
+    }
+
+    /* Now our own check. If we don't have any GPS port, we're done */
+    if (!mm_base_modem_peek_port_gps (MM_BASE_MODEM (self))) {
+        mm_dbg ("No GPS data port found: no GPS capabilities");
+        g_task_return_int (task, sources);
+        g_object_unref (task);
+        return;
+    }
+
+    /* Cache sources supported by the parent */
+    g_task_set_task_data (task, GUINT_TO_POINTER (sources), NULL);
+
+    /* Probe all GPS features */
+    probe_gps_features (task);
+}
+
+void
+mm_shared_simtech_location_load_capabilities (MMIfaceModemLocation *self,
+                                              GAsyncReadyCallback   callback,
+                                              gpointer              user_data)
+{
+    Private *priv;
+    GTask   *task;
+
+    priv = get_private (MM_SHARED_SIMTECH (self));
+    task = g_task_new (self, NULL, callback, user_data);
+
+    g_assert (priv->iface_modem_location_parent);
+    g_assert (priv->iface_modem_location_parent->load_capabilities);
+    g_assert (priv->iface_modem_location_parent->load_capabilities_finish);
+
+    priv->iface_modem_location_parent->load_capabilities (self,
+                                                          (GAsyncReadyCallback)parent_load_capabilities_ready,
+                                                          task);
+}
+
+/*****************************************************************************/
+/* Disable location gathering (Location interface) */
+
+gboolean
+mm_shared_simtech_disable_location_gathering_finish (MMIfaceModemLocation  *self,
+                                                     GAsyncResult          *res,
+                                                     GError               **error)
+{
+    return g_task_propagate_boolean (G_TASK (res), error);
+}
+
+static void
+disable_cgps_ready (MMBaseModem  *self,
+                    GAsyncResult *res,
+                    GTask        *task)
+{
+    MMModemLocationSource  source;
+    Private               *priv;
+    GError                *error = NULL;
+
+    priv = get_private (MM_SHARED_SIMTECH (self));
+
+    mm_base_modem_at_command_finish (self, res, &error);
+
+    /* Only use the GPS port in NMEA/RAW setups */
+    source = (MMModemLocationSource) GPOINTER_TO_UINT (g_task_get_task_data (task));
+    if (source & (MM_MODEM_LOCATION_SOURCE_GPS_NMEA | MM_MODEM_LOCATION_SOURCE_GPS_RAW)) {
+        MMPortSerialGps *gps_port;
+
+        /* Even if we get an error here, we try to close the GPS port */
+        gps_port = mm_base_modem_peek_port_gps (MM_BASE_MODEM (self));
+        if (gps_port)
+            mm_port_serial_close (MM_PORT_SERIAL (gps_port));
+    }
+
+    if (error)
+        g_task_return_error (task, error);
+    else {
+        priv->enabled_sources &= source;
+        g_task_return_boolean (task, TRUE);
+    }
+    g_object_unref (task);
+}
+
+static void
+parent_disable_location_gathering_ready (MMIfaceModemLocation *self,
+                                         GAsyncResult         *res,
+                                         GTask                *task)
+{
+    GError  *error;
+    Private *priv;
+
+    priv = get_private (MM_SHARED_SIMTECH (self));
+
+    g_assert (priv->iface_modem_location_parent);
+    if (!priv->iface_modem_location_parent->disable_location_gathering_finish (self, res, &error))
+        g_task_return_error (task, error);
+    else
+        g_task_return_boolean (task, TRUE);
+    g_object_unref (task);
+}
+
+void
+mm_shared_simtech_disable_location_gathering (MMIfaceModemLocation  *self,
+                                              MMModemLocationSource  source,
+                                              GAsyncReadyCallback    callback,
+                                              gpointer               user_data)
+{
+    MMModemLocationSource  enabled_sources;
+    Private               *priv;
+    GTask                 *task;
+
+    task = g_task_new (self, NULL, callback, user_data);
+    g_task_set_task_data (task, GUINT_TO_POINTER (source), NULL);
+
+    priv = get_private (MM_SHARED_SIMTECH (self));
+    g_assert (priv->iface_modem_location_parent);
+
+    /* Only consider request if it applies to one of the sources we are
+     * supporting, otherwise run parent disable */
+    if (!(priv->supported_sources & source)) {
+        /* If disabling implemented by the parent, run it. */
+        if (priv->iface_modem_location_parent->disable_location_gathering &&
+            priv->iface_modem_location_parent->disable_location_gathering_finish) {
+            priv->iface_modem_location_parent->disable_location_gathering (self,
+                                                                           source,
+                                                                           (GAsyncReadyCallback)parent_disable_location_gathering_ready,
+                                                                           task);
+            return;
+        }
+        /* Otherwise, we're done */
+        g_task_return_boolean (task, TRUE);
+        g_object_unref (task);
+        return;
+    }
+
+    /* We only expect GPS sources here */
+    g_assert (source & (MM_MODEM_LOCATION_SOURCE_GPS_NMEA |
+                        MM_MODEM_LOCATION_SOURCE_GPS_RAW |
+                        MM_MODEM_LOCATION_SOURCE_GPS_UNMANAGED));
+
+    /* Flag as disabled to see how many others we would have left enabled */
+    enabled_sources = priv->enabled_sources;
+    enabled_sources &= ~source;
+
+    /* If there are still GPS-related sources enabled, do nothing else */
+    if (enabled_sources & (MM_MODEM_LOCATION_SOURCE_GPS_NMEA |
+                           MM_MODEM_LOCATION_SOURCE_GPS_RAW |
+                           MM_MODEM_LOCATION_SOURCE_GPS_UNMANAGED)) {
+        priv->enabled_sources &= ~source;
+        g_task_return_boolean (task, TRUE);
+        g_object_unref (task);
+        return;
+    }
+
+    /* Stop GPS engine if all GPS-related sources are disabled */
+    g_assert (priv->cgps_support == FEATURE_SUPPORTED);
+    mm_base_modem_at_command (MM_BASE_MODEM (self),
+                              "+CGPS=0",
+                              10,
+                              FALSE,
+                              (GAsyncReadyCallback) disable_cgps_ready,
+                              task);
+}
+
+/*****************************************************************************/
+/* Enable location gathering (Location interface) */
+
+gboolean
+mm_shared_simtech_enable_location_gathering_finish (MMIfaceModemLocation  *self,
+                                                    GAsyncResult          *res,
+                                                    GError               **error)
+{
+    return g_task_propagate_boolean (G_TASK (res), error);
+}
+
+static void
+enable_cgps_ready (MMBaseModem  *self,
+                   GAsyncResult *res,
+                   GTask        *task)
+{
+    MMModemLocationSource  source;
+    GError                *error = NULL;
+    Private               *priv;
+
+    priv = get_private (MM_SHARED_SIMTECH (self));
+
+    if (!mm_base_modem_at_command_finish (self, res, &error)) {
+        g_task_return_error (task, error);
+        g_object_unref (task);
+        return;
+    }
+
+    /* Only use the GPS port in NMEA/RAW setups */
+    source = (MMModemLocationSource) GPOINTER_TO_UINT (g_task_get_task_data (task));
+    if (source & (MM_MODEM_LOCATION_SOURCE_GPS_NMEA |
+                  MM_MODEM_LOCATION_SOURCE_GPS_RAW)) {
+        MMPortSerialGps *gps_port;
+
+        gps_port = mm_base_modem_peek_port_gps (MM_BASE_MODEM (self));
+        if (!gps_port || !mm_port_serial_open (MM_PORT_SERIAL (gps_port), &error)) {
+            if (error)
+                g_task_return_error (task, error);
+            else
+                g_task_return_new_error (task, MM_CORE_ERROR, MM_CORE_ERROR_FAILED,
+                                         "Couldn't open raw GPS serial port");
+            g_object_unref (task);
+            return;
+        }
+    }
+
+    priv->enabled_sources |= source;
+    g_task_return_boolean (task, TRUE);
+    g_object_unref (task);
+}
+
+static void
+parent_enable_location_gathering_ready (MMIfaceModemLocation *self,
+                                        GAsyncResult         *res,
+                                        GTask                *task)
+{
+    GError  *error;
+    Private *priv;
+
+    priv = get_private (MM_SHARED_SIMTECH (self));
+
+    g_assert (priv->iface_modem_location_parent);
+    if (!priv->iface_modem_location_parent->enable_location_gathering_finish (self, res, &error))
+        g_task_return_error (task, error);
+    else
+        g_task_return_boolean (task, TRUE);
+    g_object_unref (task);
+}
+
+void
+mm_shared_simtech_enable_location_gathering (MMIfaceModemLocation  *self,
+                                             MMModemLocationSource  source,
+                                             GAsyncReadyCallback    callback,
+                                             gpointer               user_data)
+{
+    Private *priv;
+    GTask   *task;
+
+    task = g_task_new (self, NULL, callback, user_data);
+    g_task_set_task_data (task, GUINT_TO_POINTER (source), NULL);
+
+    priv = get_private (MM_SHARED_SIMTECH (self));
+    g_assert (priv->iface_modem_location_parent);
+    g_assert (priv->iface_modem_location_parent->enable_location_gathering);
+    g_assert (priv->iface_modem_location_parent->enable_location_gathering_finish);
+
+    /* Only consider request if it applies to one of the sources we are
+     * supporting, otherwise run parent enable */
+    if (!(priv->supported_sources & source)) {
+        priv->iface_modem_location_parent->enable_location_gathering (self,
+                                                                      source,
+                                                                      (GAsyncReadyCallback)parent_enable_location_gathering_ready,
+                                                                      task);
+        return;
+    }
+
+    /* We only expect GPS sources here */
+    g_assert (source & (MM_MODEM_LOCATION_SOURCE_GPS_NMEA |
+                        MM_MODEM_LOCATION_SOURCE_GPS_RAW |
+                        MM_MODEM_LOCATION_SOURCE_GPS_UNMANAGED));
+
+    /* If GPS already started, store new flag and we're done */
+    if (priv->enabled_sources & (MM_MODEM_LOCATION_SOURCE_GPS_NMEA |
+                                 MM_MODEM_LOCATION_SOURCE_GPS_RAW |
+                                 MM_MODEM_LOCATION_SOURCE_GPS_UNMANAGED)) {
+        priv->enabled_sources |= source;
+        g_task_return_boolean (task, TRUE);
+        g_object_unref (task);
+        return;
+    }
+
+    g_assert (priv->cgps_support == FEATURE_SUPPORTED);
+    mm_base_modem_at_command (MM_BASE_MODEM (self),
+                              "+CGPS=1,1",
+                              10,
+                              FALSE,
+                              (GAsyncReadyCallback) enable_cgps_ready,
+                              task);
+}
+
+/*****************************************************************************/
+
+static void
+shared_simtech_init (gpointer g_iface)
+{
+}
+
+GType
+mm_shared_simtech_get_type (void)
+{
+    static GType shared_simtech_type = 0;
+
+    if (!G_UNLIKELY (shared_simtech_type)) {
+        static const GTypeInfo info = {
+            sizeof (MMSharedSimtech),  /* class_size */
+            shared_simtech_init,       /* base_init */
+            NULL,                  /* base_finalize */
+        };
+
+        shared_simtech_type = g_type_register_static (G_TYPE_INTERFACE, "MMSharedSimtech", &info, 0);
+        g_type_interface_add_prerequisite (shared_simtech_type, MM_TYPE_IFACE_MODEM_LOCATION);
+    }
+
+    return shared_simtech_type;
+}
diff --git a/plugins/simtech/mm-shared-simtech.h b/plugins/simtech/mm-shared-simtech.h
new file mode 100644
index 00000000..48342f3c
--- /dev/null
+++ b/plugins/simtech/mm-shared-simtech.h
@@ -0,0 +1,73 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details:
+ *
+ * Copyright (C) 2019 Aleksander Morgado <aleksander@aleksander.es>
+ */
+
+#ifndef MM_SHARED_SIMTECH_H
+#define MM_SHARED_SIMTECH_H
+
+#include <glib-object.h>
+#include <gio/gio.h>
+
+#define _LIBMM_INSIDE_MM
+#include <libmm-glib.h>
+
+#include "mm-broadband-modem.h"
+#include "mm-iface-modem.h"
+#include "mm-iface-modem-location.h"
+#include "mm-iface-modem-voice.h"
+#include "mm-iface-modem-time.h"
+
+#define MM_TYPE_SHARED_SIMTECH               (mm_shared_simtech_get_type ())
+#define MM_SHARED_SIMTECH(obj)               (G_TYPE_CHECK_INSTANCE_CAST ((obj), MM_TYPE_SHARED_SIMTECH, MMSharedSimtech))
+#define MM_IS_SHARED_SIMTECH(obj)            (G_TYPE_CHECK_INSTANCE_TYPE ((obj), MM_TYPE_SHARED_SIMTECH))
+#define MM_SHARED_SIMTECH_GET_INTERFACE(obj) (G_TYPE_INSTANCE_GET_INTERFACE ((obj), MM_TYPE_SHARED_SIMTECH, MMSharedSimtech))
+
+typedef struct _MMSharedSimtech MMSharedSimtech;
+
+struct _MMSharedSimtech {
+    GTypeInterface g_iface;
+
+    /* Peek location interface of the parent class of the object */
+    MMIfaceModemLocation *  (* peek_parent_location_interface) (MMSharedSimtech *self);
+};
+
+GType mm_shared_simtech_get_type (void);
+
+/*****************************************************************************/
+/* Location interface */
+
+void                  mm_shared_simtech_location_load_capabilities        (MMIfaceModemLocation  *self,
+                                                                           GAsyncReadyCallback    callback,
+                                                                           gpointer               user_data);
+MMModemLocationSource mm_shared_simtech_location_load_capabilities_finish (MMIfaceModemLocation  *self,
+                                                                           GAsyncResult          *res,
+                                                                           GError               **error);
+
+void                  mm_shared_simtech_enable_location_gathering         (MMIfaceModemLocation   *self,
+                                                                           MMModemLocationSource   source,
+                                                                           GAsyncReadyCallback     callback,
+                                                                           gpointer                user_data);
+gboolean              mm_shared_simtech_enable_location_gathering_finish  (MMIfaceModemLocation   *self,
+                                                                           GAsyncResult           *res,
+                                                                           GError                **error);
+
+void                  mm_shared_simtech_disable_location_gathering        (MMIfaceModemLocation   *self,
+                                                                           MMModemLocationSource   source,
+                                                                           GAsyncReadyCallback     callback,
+                                                                           gpointer                user_data);
+gboolean              mm_shared_simtech_disable_location_gathering_finish (MMIfaceModemLocation   *self,
+                                                                           GAsyncResult           *res,
+                                                                           GError                **error);
+
+#endif  /* MM_SHARED_SIMTECH_H */