example to work with async loading

Author: viswajith-g

examples/tests/app_loader/main.c

@@ -21,6 +21,7 @@
 
 static bool setup_done = false;     // to check if setup is done
 static bool write_done = false;     // to check if writing to flash is done
+static bool load_done  = false;     // to check if the process was loaded successfully
 
 /******************************************************************************************************
 * Callback functions
@@ -48,6 +49,14 @@ static void app_write_done_callback(__attribute__((unused)) int   length,
   write_done = true;
 }
 
+static void app_load_done_callback( __attribute__((unused)) int   length,
+                                    __attribute__((unused)) int   arg1,
+                                    __attribute__((unused)) int   arg2,
+                                    __attribute__((unused)) void *ud)
+{
+  load_done = true;
+}
+
 static void button_callback(int                            btn_num,
                             int                            val,
                             __attribute__ ((unused)) int   arg2,
@@ -75,6 +84,7 @@ static void button_callback(int                            btn_num,
         printf("[Log] Exiting Application.\n");
         tock_exit(ret); // we failed, so we exit the program.
       } else {
+        printf("[Log] Yielding for setup done.\n");
         yield_for(&setup_done);   // wait until the padding app write is done before you send your app, or it will fail during write
         setup_done = false;
         printf("[Success] Setup successful. Attempting to write app to flash now.\n");
@@ -173,6 +183,7 @@ int write_app(double size, uint8_t binary[]){
     ret = app_loader_command_write(flash_offset, FLASH_BUFFER_SIZE);
     if (ret != 0) {
       printf("[Error] Failed writing data to flash at address: 0x%lx\n", flash_offset);
+      printf("[Error] Error nature: %d\n", ret);
       return -1;
     }
     yield_for(&write_done);     // wait until write done callback
@@ -202,26 +213,34 @@ int main(void) {
     button_enable_interrupt(i);
   }
 
-  // set up the write done and button press callbacks
+  // set up the setup done callback
   int err1 = app_loader_setup_subscribe(app_setup_done_callback, NULL);
   if (err1 != 0) {
     printf("[Error] Failed to set setup done callback: %d\n", err1);
     return err1;
   }
 
-  // set up the write done and button press callbacks
+  // set up the write done callback
   int err2 = app_loader_write_subscribe(app_write_done_callback, NULL);
   if (err2 != 0) {
     printf("[Error] Failed to set flash write done callback: %d\n", err2);
     return err2;
   }
 
-  int err3 = button_subscribe(button_callback, NULL);
+  // set up the load done callback
+  int err3 = app_loader_load_subscribe(app_load_done_callback, NULL);
   if (err3 != 0) {
-    printf("[Error] Failed to set button callback: %d.\n", err3);
+    printf("[Error] Failed to set load done callback: %d\n", err3);
     return err3;
   }
 
+  // setup the button press callback
+  int err4 = button_subscribe(button_callback, NULL);
+  if (err4 != 0) {
+    printf("[Error] Failed to set button callback: %d.\n", err4);
+    return err4;
+  }
+
   // Check if the app_loader driver exists.
   int ret;
   ret = app_loader_exists();

libtock/internal/app_loader.c

@@ -16,6 +16,11 @@ int app_loader_write_subscribe(subscribe_upcall cb, void *userdata) {
   return tock_subscribe_return_to_returncode(sval);
 }
 
+int app_loader_load_subscribe(subscribe_upcall cb, void *userdata) {
+  subscribe_return_t sval = subscribe(DRIVER_NUM_APP_LOADER, 2, cb, userdata);
+  return tock_subscribe_return_to_returncode(sval);
+}
+
 int app_loader_write_buffer(uint8_t *buffer, uint32_t len) {
   allow_ro_return_t aval = allow_readonly(DRIVER_NUM_APP_LOADER, 0, (void*) buffer, len);
   return tock_allow_ro_return_to_returncode(aval);

libtock/internal/app_loader.h

@@ -59,6 +59,14 @@ int app_loader_command_write(uint32_t flash_offset, uint32_t write_length);
  */
 int app_loader_command_load(void);
 
+/*
+ * Function to setup the callback from capsule.
+ * This function takes in the function that will be executed
+ * when the callback is triggered.
+ */
+int app_loader_load_subscribe(subscribe_upcall cb, void *userdata);
+
+
 /*
  * Internal function to write new app to flash. Takes app size as argument.
  */