go into safe mode if not CIRCUITPY available

locale/circuitpython.pot

@@ -659,6 +659,10 @@ msgstr ""
 msgid "CBC blocks must be multiples of 16 bytes"
 msgstr ""
 
+#: supervisor/shared/safe_mode.c
+msgid "CIRCUITPY drive could not be found or created."
+msgstr ""
+
 #: ports/espressif/bindings/espidf/__init__.c ports/espressif/esp_error.c
 msgid "CRC or checksum was invalid"
 msgstr ""

main.c

@@ -811,7 +811,11 @@ int __attribute__((used)) main(void) {
     // Create a new filesystem only if we're not in a safe mode.
     // A power brownout here could make it appear as if there's
     // no SPI flash filesystem, and we might erase the existing one.
-    filesystem_init(safe_mode == NO_SAFE_MODE, false);
+
+    // Check whether CIRCUITPY is available. Don't check if it already hasn't been found.
+    if (safe_mode != NO_CIRCUITPY && !filesystem_init(safe_mode == NO_SAFE_MODE, false)) {
+        reset_into_safe_mode(NO_CIRCUITPY);
+    }
 
     // displays init after filesystem, since they could share the flash SPI
     board_init();

shared-module/storage/__init__.c

@@ -271,7 +271,7 @@ void common_hal_storage_erase_filesystem(void) {
     usb_disconnect();
     #endif
     mp_hal_delay_ms(1000);
-    filesystem_init(false, true); // Force a re-format.
+    (void)filesystem_init(false, true);  // Force a re-format. Ignore failure.
     common_hal_mcu_reset();
     // We won't actually get here, since we're resetting.
 }

supervisor/filesystem.h

@@ -35,7 +35,7 @@ extern volatile bool filesystem_flush_requested;
 
 void filesystem_background(void);
 void filesystem_tick(void);
-void filesystem_init(bool create_allowed, bool force_create);
+bool filesystem_init(bool create_allowed, bool force_create);
 void filesystem_flush(void);
 bool filesystem_present(void);
 void filesystem_set_internal_writable_by_usb(bool usb_writable);

supervisor/shared/filesystem.c

@@ -86,7 +86,7 @@ static void make_sample_code_file(FATFS *fatfs) {
 
 // we don't make this function static because it needs a lot of stack and we
 // want it to be executed without using stack within main() function
-void filesystem_init(bool create_allowed, bool force_create) {
+bool filesystem_init(bool create_allowed, bool force_create) {
     // init the vfs object
     fs_user_mount_t *vfs_fat = &_internal_vfs;
     vfs_fat->blockdev.flags = 0;
@@ -102,11 +102,11 @@ void filesystem_init(bool create_allowed, bool force_create) {
         formats |= FM_EXFAT | FM_FAT32;
         #endif
         res = f_mkfs(&vfs_fat->fatfs, formats, 0, working_buf, sizeof(working_buf));
+        if (res != FR_OK) {
+            return false;
+        }
         // Flush the new file system to make sure it's repaired immediately.
         supervisor_flash_flush();
-        if (res != FR_OK) {
-            return;
-        }
 
         // set label
         #ifdef CIRCUITPY_DRIVE_LABEL
@@ -115,13 +115,13 @@ void filesystem_init(bool create_allowed, bool force_create) {
         res = f_setlabel(&vfs_fat->fatfs, "CIRCUITPY");
         #endif
         if (res != FR_OK) {
-            return;
+            return false;
         }
 
         // inhibit file indexing on MacOS
         res = f_mkdir(&vfs_fat->fatfs, "/.fseventsd");
         if (res != FR_OK) {
-            return;
+            return false;
         }
         make_empty_file(&vfs_fat->fatfs, "/.metadata_never_index");
         make_empty_file(&vfs_fat->fatfs, "/.Trashes");
@@ -132,13 +132,13 @@ void filesystem_init(bool create_allowed, bool force_create) {
         // create empty lib directory
         res = f_mkdir(&vfs_fat->fatfs, "/lib");
         if (res != FR_OK) {
-            return;
+            return false;
         }
 
         // and ensure everything is flushed
         supervisor_flash_flush();
     } else if (res != FR_OK) {
-        return;
+        return false;
     }
     mp_vfs_mount_t *vfs = &_mp_vfs;
     vfs->str = "/";
@@ -150,6 +150,8 @@ void filesystem_init(bool create_allowed, bool force_create) {
     // The current directory is used as the boot up directory.
     // It is set to the internal flash filesystem by default.
     MP_STATE_PORT(vfs_cur) = vfs;
+
+    return true;
 }
 
 void filesystem_flush(void) {

supervisor/shared/safe_mode.c

@@ -175,6 +175,8 @@ void print_safe_mode_message(safe_mode_t reason) {
         case WATCHDOG_RESET:
             message = translate("Watchdog timer expired.");
             break;
+        case NO_CIRCUITPY:
+            message = translate("CIRCUITPY drive could not be found or created.");
         default:
             break;
     }

supervisor/shared/safe_mode.h

@@ -48,6 +48,7 @@ typedef enum {
     USB_TOO_MANY_INTERFACE_NAMES,
     USB_BOOT_DEVICE_NOT_INTERFACE_ZERO,
     NO_HEAP,
+    NO_CIRCUITPY,
 } safe_mode_t;
 
 safe_mode_t wait_for_safe_mode_reset(void);

supervisor/stub/filesystem.c

@@ -26,9 +26,10 @@
 
 #include "supervisor/filesystem.h"
 
-void filesystem_init(bool create_allowed, bool force_create) {
+bool filesystem_init(bool create_allowed, bool force_create) {
     (void)create_allowed;
     (void)force_create;
+    return true;
 }
 
 void filesystem_flush(void) {