at: make sure we read the full response before processing it

The response can include the command and an error number, so we want to 
only check it contains ERROR, even if it's replying more than just the 
'ERROR' string.

meson.build

@@ -44,6 +44,7 @@ mgr_deps = [
     dependency('glib-2.0'),
     dependency('gio-unix-2.0'),
     dependency('libgpiod'),
+    dependency('libusb-1.0'),
     dependency('mm-glib'),
 ]
 

src/at.c

@@ -31,7 +31,7 @@ static int configure_serial(const char *tty)
     struct termios ttycfg;
     int fd;
 
-    fd = open(tty, O_RDWR | O_NOCTTY);
+    fd = open(tty, O_RDWR | O_NOCTTY | O_NONBLOCK);
     if (fd > 0) {
         tcgetattr(fd, &ttycfg);
         ttycfg.c_iflag &= ~(IGNBRK | BRKINT | ICRNL | INLCR | PARMRK | INPCK | ISTRIP | IXON);
@@ -143,7 +143,6 @@ static int append_at_command(struct EG25Manager *manager,
     if (!at_cmd)
         return -1;
 
-    at_cmd->retries = 0;
     at_cmd->cmd = g_strdup(cmd);
     if (subcmd)
         at_cmd->subcmd = g_strdup(subcmd);
@@ -157,22 +156,33 @@ static int append_at_command(struct EG25Manager *manager,
     return 0;
 }
 
+#define READ_BUFFER_SIZE 256
+
 static gboolean modem_response(gint fd,
                                GIOCondition event,
                                gpointer data)
 {
     struct EG25Manager *manager = data;
-    char response[256];
-    int ret;
+    char response[READ_BUFFER_SIZE*4+1];
+    char tmp[READ_BUFFER_SIZE];
+    ssize_t ret, pos = 0;
 
     /*
-     * TODO: several reads can be necessary to get the full response, we could
-     * loop until we read 0 chars with a reasonable delay between attempts
+     * Several reads can be necessary to get the full response, so we loop
+     * until we read 0 chars with a reasonable delay between attempts
      * (remember the transfer rate is 115200 here)
      */
-    ret = read(fd, response, sizeof(response));
-    if (ret > 0) {
-        response[ret] = 0;
+    do {
+        ret = read(fd, tmp, sizeof(tmp));
+        if (ret > 0) {
+            memcpy(&response[pos], tmp, ret);
+            pos += ret;
+            usleep(10000);
+        }
+    } while (ret > 0 && pos < (sizeof(response) - 1));
+
+    if (pos > 0) {
+        response[pos] = 0;
         g_strstrip(response);
         if (strlen(response) == 0)
             return TRUE;
@@ -181,7 +191,7 @@ static gboolean modem_response(gint fd,
 
         if (strcmp(response, "RDY") == 0)
             manager->modem_state = EG25_STATE_STARTED;
-        else if (strcmp(response, "ERROR") == 0)
+        else if (strstr(response, "ERROR"))
             retry_at_command(manager);
         else if (strstr(response, "OK"))
             process_at_result(manager, response);
@@ -249,7 +259,7 @@ void at_sequence_configure(struct EG25Manager *manager)
 
 void at_sequence_suspend(struct EG25Manager *manager)
 {
-    append_at_command(manager, "QGPS", NULL, NULL, "0");
+    append_at_command(manager, "QGPS", NULL, "0", NULL);
     append_at_command(manager, "QCFG", "urc/cache", "1", NULL);
     send_at_command(manager);
 }
@@ -257,7 +267,7 @@ void at_sequence_suspend(struct EG25Manager *manager)
 void at_sequence_resume(struct EG25Manager *manager)
 {
     append_at_command(manager, "QCFG", "urc/cache", "0", NULL);
-    append_at_command(manager, "QGPS", NULL, NULL, "1");
+    append_at_command(manager, "QGPS", NULL, "1", NULL);
     send_at_command(manager);
 }
 

src/gpio.c

@@ -57,7 +57,7 @@ int gpio_sequence_poweron(struct EG25Manager *manager)
     sleep(1);
     gpiod_line_set_value(manager->gpio_out[GPIO_OUT_PWRKEY], 0);
 
-    g_message("Executed power-on sequence");
+    g_message("Executed power-on/off sequence");
 
     return 0;
 }
@@ -172,13 +172,16 @@ int gpio_init(struct EG25Manager *manager)
     return 0;
 }
 
-gboolean gpio_check_poweroff(struct EG25Manager *manager)
+gboolean gpio_check_poweroff(struct EG25Manager *manager, gboolean keep_down)
 {
     if (manager->gpio_in[GPIO_IN_STATUS] &&
         gpiod_line_get_value(manager->gpio_in[GPIO_IN_STATUS]) == 1) {
 
-        // Asserting RESET line to prevent modem from rebooting
-        gpiod_line_set_value(manager->gpio_out[GPIO_OUT_RESET], 1);
+        if (keep_down) {
+            // Asserting RESET line to prevent modem from rebooting
+            gpiod_line_set_value(manager->gpio_out[GPIO_OUT_RESET], 1);
+        }
+
         return TRUE;
     }
 

src/gpio.h

@@ -16,4 +16,4 @@ int gpio_sequence_shutdown(struct EG25Manager *state);
 int gpio_sequence_suspend(struct EG25Manager *state);
 int gpio_sequence_resume(struct EG25Manager *state);
 
-gboolean gpio_check_poweroff(struct EG25Manager *manager);
+gboolean gpio_check_poweroff(struct EG25Manager *manager, gboolean keep_down);

src/manager.c

@@ -16,6 +16,10 @@
 #include <unistd.h>
 
 #include <glib-unix.h>
+#include <libusb.h>
+
+#define EG25_USB_VID 0x2c7c
+#define EG25_USB_PID 0x0125
 
 static gboolean quit_app(struct EG25Manager *manager)
 {
@@ -32,7 +36,7 @@ static gboolean quit_app(struct EG25Manager *manager)
         gpio_sequence_shutdown(manager);
         manager->modem_state = EG25_STATE_FINISHING;
         for (i = 0; i < 30; i++) {
-            if (gpio_check_poweroff(manager))
+            if (gpio_check_poweroff(manager, TRUE))
                 break;
             sleep(1);
         }
@@ -46,9 +50,40 @@ static gboolean quit_app(struct EG25Manager *manager)
 
 static gboolean modem_start(struct EG25Manager *manager)
 {
-    g_message("Starting modem...");
-    gpio_sequence_poweron(manager);
-    manager->modem_state = EG25_STATE_POWERED;
+    ssize_t i, count;
+    gboolean should_boot = TRUE;
+    libusb_context *ctx = NULL;
+    libusb_device **devices = NULL;
+    struct libusb_device_descriptor desc;
+
+    if (manager->braveheart) {
+        // BH don't have the STATUS line connected, so check if USB device is present
+        libusb_init(&ctx);
+
+        count = libusb_get_device_list(ctx, &devices);
+        for (i = 0; i < count; i++) {
+            libusb_get_device_descriptor(devices[i], &desc);
+            if (desc.idVendor == EG25_USB_VID && desc.idProduct == EG25_USB_PID) {
+                g_message("Found corresponding USB device, modem already powered");
+                should_boot = FALSE;
+                break;
+            }
+        }
+
+        libusb_free_device_list(devices, 1);
+        libusb_exit(ctx);
+    } else if (!gpio_check_poweroff(manager, FALSE)) {
+        g_message("STATUS is low, modem already powered");
+        should_boot = FALSE;
+    }
+
+    if (should_boot) {
+        g_message("Starting modem...");
+        gpio_sequence_poweron(manager);
+        manager->modem_state = EG25_STATE_POWERED;
+    } else {
+        manager->modem_state = EG25_STATE_STARTED;
+    }
 
     return FALSE;
 }
@@ -100,14 +135,20 @@ error:
     manager->modem_state = EG25_STATE_RESETTING;
 }
 
-void modem_suspend(struct EG25Manager *manager)
+void modem_suspend_pre(struct EG25Manager *manager)
 {
+    manager->modem_state = EG25_STATE_SUSPENDING;
     gpio_sequence_suspend(manager);
+}
+
+void modem_suspend_post(struct EG25Manager *manager)
+{
     at_sequence_suspend(manager);
 }
 
 void modem_resume_pre(struct EG25Manager *manager)
 {
+    manager->modem_state = EG25_STATE_RESUMING;
     gpio_sequence_resume(manager);
 }
 

src/manager.h

@@ -51,7 +51,8 @@ struct EG25Manager {
 
 void modem_configure(struct EG25Manager *data);
 void modem_reset(struct EG25Manager *data);
-void modem_suspend(struct EG25Manager *data);
+void modem_suspend_pre(struct EG25Manager *data);
+void modem_suspend_post(struct EG25Manager *data);
 void modem_resume_pre(struct EG25Manager *data);
 void modem_resume_post(struct EG25Manager *data);
 void modem_update_state(struct EG25Manager *data, MMModemState state);

src/mm-iface.c

@@ -132,6 +132,9 @@ static void object_removed_cb(struct EG25Manager *manager, GDBusObject *object)
     path = g_dbus_object_get_object_path(object);
     g_message("ModemManager object `%s' removed", path);
 
+    if (manager->modem_state == EG25_STATE_SUSPENDING)
+        modem_suspend_post(manager);
+
     manager->mm_modem = NULL;
     if (manager->modem_usb_id) {
         g_free(manager->modem_usb_id);

src/suspend.c

@@ -92,13 +92,11 @@ static void signal_cb(GDBusProxy *proxy,
 
     if (is_about_to_suspend) {
         g_message("system is about to suspend");
-        manager->modem_state = EG25_STATE_SUSPENDING;
-        modem_suspend(manager);
+        modem_suspend_pre(manager);
     } else {
         g_message("system is resuming");
         take_inhibitor(manager);
         modem_resume_pre(manager);
-        manager->modem_state = EG25_STATE_RESUMING;
         manager->suspend_source = g_timeout_add_seconds(8, G_SOURCE_FUNC(check_modem_resume), manager);
     }
 }