Start tweaking the workflow to sleep

17 files changed, 282 insertions, 90 deletions

diff --git a/main.c b/main.c
index 328c3bbcb..1854a1407 100755
--- a/main.c
+++ b/main.c
@@ -88,6 +88,10 @@
 #include "common-hal/canio/CAN.h"
 #endif
 
+#if CIRCUITPY_SLEEPIO
+#include "shared-bindings/sleepio/__init__.h"
+#endif
+
 void do_str(const char *src, mp_parse_input_kind_t input_kind) {
     mp_lexer_t *lex = mp_lexer_new_from_str_len(MP_QSTR__lt_stdin_gt_, src, strlen(src), 0);
     if (lex == NULL) {
@@ -303,19 +307,6 @@ bool run_code_py(safe_mode_t safe_mode) {
         }
     }
 
-    for (uint8_t i = 0; i<=100; i++) {
-        if (!usb_msc_ejected()) {
-            //Go into light sleep
-            break;
-        }
-        mp_hal_delay_ms(10);
-    }
-
-    if (usb_msc_ejected()) {
-        //Go into deep sleep
-        common_hal_mcu_deep_sleep();
-    }
-
     // Display a different completion message if the user has no USB attached (cannot save files)
     if (!serial_connected_at_start) {
         serial_write_compressed(translate("\nCode done running. Waiting for reload.\n"));
@@ -326,6 +317,14 @@ bool run_code_py(safe_mode_t safe_mode) {
     bool refreshed_epaper_display = false;
     #endif
     rgb_status_animation_t animation;
+    bool ok = result->return_code != PYEXEC_EXCEPTION;
+    #if CIRCUITPY_SLEEPIO
+    // If USB isn't enumerated then deep sleep.
+    if (ok && !supervisor_workflow_active() && supervisor_ticks_ms64() > CIRCUITPY_USB_ENUMERATION_DELAY * 1024) {
+        common_hal_sleepio_deep_sleep();
+    }
+    #endif
+    // Show the animation every N seconds.
     prep_rgb_status_animation(&result, found_main, safe_mode, &animation);
     while (true) {
         RUN_BACKGROUND_TASKS;
@@ -358,8 +357,24 @@ bool run_code_py(safe_mode_t safe_mode) {
             refreshed_epaper_display = maybe_refresh_epaperdisplay();
         }
         #endif
-
-        tick_rgb_status_animation(&animation);
+        bool animation_done = tick_rgb_status_animation(&animation);
+        if (animation_done && supervisor_workflow_active()) {
+            #if CIRCUITPY_SLEEPIO
+            int64_t remaining_enumeration_wait = CIRCUITPY_USB_ENUMERATION_DELAY * 1024 - supervisor_ticks_ms64();
+            // If USB isn't enumerated then deep sleep after our waiting period.
+            if (ok && remaining_enumeration_wait < 0) {
+                common_hal_sleepio_deep_sleep();
+                return; // Doesn't actually get here.
+            }
+            #endif
+            // Wake up every so often to flash the error code.
+            if (!ok) {
+                port_interrupt_after_ticks(CIRCUITPY_FLASH_ERROR_PERIOD * 1024);
+            } else {
+                port_interrupt_after_ticks(remaining_enumeration_wait);
+            }
+            port_sleep_until_interrupt();
+        }
     }
 }
 
@@ -406,7 +421,9 @@ void __attribute__ ((noinline)) run_boot_py(safe_mode_t safe_mode) {
         if (!skip_boot_output) {
             // Wait 1.5 seconds before opening CIRCUITPY_BOOT_OUTPUT_FILE for write,
             // in case power is momentary or will fail shortly due to, say a low, battery.
-            mp_hal_delay_ms(1500);
+            if (common_hal_sleepio_get_reset_reason() == RESET_REASON_POWER_VALID) {
+                mp_hal_delay_ms(1500);
+            }
 
             // USB isn't up, so we can write the file.
             filesystem_set_internal_writable_by_usb(false);
diff --git a/ports/esp32s2/common-hal/alarm_touch/__init__.c b/ports/esp32s2/common-hal/alarm_touch/__init__.c
deleted file mode 100644
index df32b2693..000000000
--- a/ports/esp32s2/common-hal/alarm_touch/__init__.c
+++ /dev/null
@@ -1,7 +0,0 @@
-#include "esp_sleep.h"
-
-#include "shared-bindings/alarm_touch/__init__.h"
-
-void common_hal_alarm_touch_disable (void) {
-    esp_sleep_disable_wakeup_source(ESP_SLEEP_WAKEUP_TOUCHPAD);
-}
diff --git a/shared-bindings/alarm_touch/__init__.c b/shared-bindings/alarm_touch/__init__.c
deleted file mode 100644
index 5f5a156d8..000000000
--- a/shared-bindings/alarm_touch/__init__.c
+++ /dev/null
@@ -1,28 +0,0 @@
-#include "py/obj.h"
-#include "shared-bindings/alarm_touch/__init__.h"
-
-//| """alarm_touch module
-//|
-//| The `alarm_touch` module implements deep sleep."""
-
-STATIC mp_obj_t alarm_touch_disable(void) {
-    common_hal_alarm_touch_disable();
-    return mp_const_none;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_0(alarm_touch_disable_obj, alarm_touch_disable);
-
-STATIC const mp_rom_map_elem_t alarm_touch_module_globals_table[] = {
-    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_alarm_touch) },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_Disable), MP_ROM_PTR(&alarm_touch_disable_obj) },
-};
-STATIC MP_DEFINE_CONST_DICT(alarm_touch_module_globals, alarm_touch_module_globals_table);
-
-const mp_obj_module_t alarm_touch_module = {
-    .base = { &mp_type_module },
-    .globals = (mp_obj_dict_t*)&alarm_touch_module_globals,
-};
-
-const mp_obj_type_t alarm_touch_type = {
-    { &mp_type_type },
-    .name = MP_QSTR_touchAlarm,
-};
diff --git a/shared-bindings/alarm_touch/__init__.h b/shared-bindings/alarm_touch/__init__.h
deleted file mode 100644
index 600587d24..000000000
--- a/shared-bindings/alarm_touch/__init__.h
+++ /dev/null
@@ -1,14 +0,0 @@
-#ifndef MICROPY_INCLUDED_SHARED_BINDINGS_ALARM_TOUCH___INIT___H
-#define MICROPY_INCLUDED_SHARED_BINDINGS_ALARM_TOUCH___INIT___H
-
-#include "py/runtime.h"
-
-typedef struct {
-    mp_obj_base_t base;
-} alarm_touch_obj_t;
-
-extern const mp_obj_type_t alarm_touch_type;
-
-extern void common_hal_alarm_touch_disable (void);
-
-#endif //MICROPY_INCLUDED_SHARED_BINDINGS_ALARM_TOUCH___INIT___H
diff --git a/shared-bindings/sleepio/ResetReason.c b/shared-bindings/sleepio/ResetReason.c
new file mode 100644
index 000000000..095f4bed0
--- /dev/null
+++ b/shared-bindings/sleepio/ResetReason.c
@@ -0,0 +1,61 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/enum.h"
+
+#include "shared-bindings/sleepio/ResetReason.h"
+
+MAKE_ENUM_VALUE(sleepio_reset_reason_type, reset_reason, POWER_VALID, RESET_REASON_POWER_VALID);
+MAKE_ENUM_VALUE(sleepio_reset_reason_type, reset_reason, SOFTWARE, RESET_REASON_SOFTWARE);
+MAKE_ENUM_VALUE(sleepio_reset_reason_type, reset_reason, DEEP_SLEEP_ALARM, RESET_REASON_DEEP_SLEEP_ALARM);
+MAKE_ENUM_VALUE(sleepio_reset_reason_type, reset_reason, EXTERNAL, RESET_REASON_EXTERNAL);
+
+//| class ResetReason:
+//|     """The reason the chip was last reset"""
+//|
+//|     POWER_VALID: object
+//|     """The chip was reset and started once power levels were valid."""
+//|
+//|     SOFTWARE: object
+//|     """The chip was reset from software."""
+//|
+//|     DEEP_SLEEP_ALARM: object
+//|     """The chip was reset for deep sleep and started by an alarm."""
+//|
+//|     EXTERNAL: object
+//|     """The chip was reset by an external input such as a button."""
+//|
+MAKE_ENUM_MAP(sleepio_reset_reason) {
+    MAKE_ENUM_MAP_ENTRY(reset_reason, POWER_VALID),
+    MAKE_ENUM_MAP_ENTRY(reset_reason, SOFTWARE),
+    MAKE_ENUM_MAP_ENTRY(reset_reason, DEEP_SLEEP_ALARM),
+    MAKE_ENUM_MAP_ENTRY(reset_reason, EXTERNAL),
+};
+STATIC MP_DEFINE_CONST_DICT(sleepio_reset_reason_locals_dict, sleepio_reset_reason_locals_table);
+
+MAKE_PRINTER(sleepio, sleepio_reset_reason);
+
+MAKE_ENUM_TYPE(sleepio, ResetReason, sleepio_reset_reason);
diff --git a/shared-bindings/sleepio/ResetReason.h b/shared-bindings/sleepio/ResetReason.h
new file mode 100644
index 000000000..50b8d002a
--- /dev/null
+++ b/shared-bindings/sleepio/ResetReason.h
@@ -0,0 +1,36 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+typedef enum {
+    RESET_REASON_POWER_APPLIED,
+    RESET_REASON_SOFTWARE,
+    RESET_REASON_DEEP_SLEEP_ALARM,
+    RESET_REASON_BUTTON,
+} sleepio_reset_reason_t;
+
+extern const mp_obj_type_t sleepio_reset_reason_type;
diff --git a/shared-bindings/sleepio/__init__.c b/shared-bindings/sleepio/__init__.c
index 2d5db18f0..9793c1b50 100644
--- a/shared-bindings/sleepio/__init__.c
+++ b/shared-bindings/sleepio/__init__.c
@@ -47,6 +47,10 @@
 //| """The most recent alarm to wake us up from a sleep (light or deep.)"""
 //|
 
+//| reset_reason: ResetReason
+//| """The reason the chip started up from reset state. This can may be power up or due to an alarm."""
+//|
+
 //| def sleep_until_alarm(alarm: Alarm, ...) -> Alarm:
 //|     """Performs a light sleep until woken by one of the alarms. The alarm that woke us up is
 //|        returned."""
@@ -54,14 +58,6 @@
 //|
 
 STATIC mp_obj_t sleepio_sleep_until_alarm(size_t n_args, const mp_obj_t *args) {
-    // mp_int_t size = MP_OBJ_SMALL_INT_VALUE(struct_calcsize(args[0]));
-    // vstr_t vstr;
-    // vstr_init_len(&vstr, size);
-    // byte *p = (byte*)vstr.buf;
-    // memset(p, 0, size);
-    // byte *end_p = &p[size];
-    // shared_modules_struct_pack_into(args[0], p, end_p, n_args - 1, &args[1]);
-    // return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(sleepio_sleep_until_alarm_obj, 1, MP_OBJ_FUN_ARGS_MAX, sleepio_sleep_until_alarm);
 
@@ -71,14 +67,6 @@ MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(sleepio_sleep_until_alarm_obj, 1, MP_OBJ_FUN
 //|     ...
 //|
 STATIC mp_obj_t sleepio_set_alarms(size_t n_args, const mp_obj_t *args) {
-    // mp_int_t size = MP_OBJ_SMALL_INT_VALUE(struct_calcsize(args[0]));
-    // vstr_t vstr;
-    // vstr_init_len(&vstr, size);
-    // byte *p = (byte*)vstr.buf;
-    // memset(p, 0, size);
-    // byte *end_p = &p[size];
-    // shared_modules_struct_pack_into(args[0], p, end_p, n_args - 1, &args[1]);
-    // return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(sleepio_set_alarms_obj, 1, MP_OBJ_FUN_ARGS_MAX, sleepio_set_alarms);
 
@@ -87,16 +75,23 @@ mp_map_elem_t sleepio_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_sleepio) },
 
     { MP_ROM_QSTR(MP_QSTR_wake_alarm), mp_const_none },
+    { MP_ROM_QSTR(MP_QSTR_reset_reason), mp_const_none },
 
     { MP_ROM_QSTR(MP_QSTR_sleep_until_alarm), sleepio_sleep_until_alarm_obj },
     { MP_ROM_QSTR(MP_QSTR_set_alarms), sleepio_set_alarms_obj },
 };
 STATIC MP_DEFINE_CONST_DICT(sleepio_module_globals, sleepio_module_globals_table);
 
+// These are called from common hal code to set the current wake alarm.
 void common_hal_sleepio_set_wake_alarm(mp_obj_t alarm) {
     // sleepio_module_globals_table[1].value = alarm;
 }
 
+// These are called from common hal code to set the current wake alarm.
+void common_hal_sleepio_set_reset_reason(mp_obj_t reset_reason) {
+    // sleepio_module_globals_table[1].value = alarm;
+}
+
 const mp_obj_module_t sleepio_module = {
     .base = { &mp_type_module },
     .globals = (mp_obj_dict_t*)&sleepio_module_globals,
diff --git a/shared-bindings/sleepio/__init__.h b/shared-bindings/sleepio/__init__.h
index ccd3bf4a0..6ea538055 100644
--- a/shared-bindings/sleepio/__init__.h
+++ b/shared-bindings/sleepio/__init__.h
@@ -3,8 +3,7 @@
 
 #include "py/obj.h"
 
-// This is implemented by shared-bindings so that implementations can set the
-// newest alarm source.
-extern void common_hal_sleepio_set_wake_alarm(mp_obj_t alarm);
+extern mp_obj_t common_hal_sleepio_get_wake_alarm(void);
+extern sleepio_reset_reason_t common_hal_sleepio_get_reset_reason(void);
 
 #endif  // MICROPY_INCLUDED_SHARED_BINDINGS_SLEEPIO___INIT___H
diff --git a/supervisor/serial.h b/supervisor/serial.h
index 9c2d44737..066886303 100644
--- a/supervisor/serial.h
+++ b/supervisor/serial.h
@@ -47,5 +47,4 @@ char serial_read(void);
 bool serial_bytes_available(void);
 bool serial_connected(void);
 
-extern volatile bool _serial_connected;
 #endif  // MICROPY_INCLUDED_SUPERVISOR_SERIAL_H
diff --git a/supervisor/shared/rgb_led_status.c b/supervisor/shared/rgb_led_status.c
index 283b9da12..bff74a1f0 100644
--- a/supervisor/shared/rgb_led_status.c
+++ b/supervisor/shared/rgb_led_status.c
@@ -367,6 +367,7 @@ void prep_rgb_status_animation(const pyexec_result_t* result,
     status->found_main = found_main;
     status->total_exception_cycle = 0;
     status->ok = result->return_code != PYEXEC_EXCEPTION;
+    status->cycles = 0;
     if (status->ok) {
         // If this isn't an exception, skip exception sorting and handling
         return;
@@ -411,14 +412,16 @@ void prep_rgb_status_animation(const pyexec_result_t* result,
     #endif
 }
 
-void tick_rgb_status_animation(rgb_status_animation_t* status) {
+bool tick_rgb_status_animation(rgb_status_animation_t* status) {
     #if defined(MICROPY_HW_NEOPIXEL) || (defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK)) || (defined(CP_RGB_STATUS_LED))
     uint32_t tick_diff = supervisor_ticks_ms32() - status->pattern_start;
     if (status->ok) {
         // All is good. Ramp ALL_DONE up and down.
         if (tick_diff > ALL_GOOD_CYCLE_MS) {
             status->pattern_start = supervisor_ticks_ms32();
-            tick_diff = 0;
+            status->cycles++;
+            new_status_color(BLACK);
+            return status->cycles;
         }
 
         uint16_t brightness = tick_diff * 255 / (ALL_GOOD_CYCLE_MS / 2);
@@ -433,7 +436,8 @@ void tick_rgb_status_animation(rgb_status_animation_t* status) {
     } else {
         if (tick_diff > status->total_exception_cycle) {
             status->pattern_start = supervisor_ticks_ms32();
-            tick_diff = 0;
+            status->cycles++;
+            return;
         }
         // First flash the file color.
         if (tick_diff < EXCEPTION_TYPE_LENGTH_MS) {
diff --git a/supervisor/shared/safe_mode.c b/supervisor/shared/safe_mode.c
index d59e754ed..fa871eeeb 100644
--- a/supervisor/shared/safe_mode.c
+++ b/supervisor/shared/safe_mode.c
@@ -52,6 +52,10 @@ safe_mode_t wait_for_safe_mode_reset(void) {
         current_safe_mode = safe_mode;
         return safe_mode;
     }
+    if (common_hal_sleepio_get_reset_reason() != RESET_REASON_POWER_VALID &&
+        common_hal_sleepio_get_reset_reason() != RESET_REASON_BUTTON) {
+        return NO_SAFE_MODE;
+    }
     port_set_saved_word(SAFE_MODE_DATA_GUARD | (MANUAL_SAFE_MODE << 8));
     // Wait for a while to allow for reset.
     temp_status_color(SAFE_MODE);
diff --git a/supervisor/shared/serial.h b/supervisor/shared/serial.h
new file mode 100644
index 000000000..84f92c337
--- /dev/null
+++ b/supervisor/shared/serial.h
@@ -0,0 +1,29 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+extern volatile bool _serial_connected;
diff --git a/supervisor/shared/usb/usb.c b/supervisor/shared/usb/usb.c
index 89fbf56f3..7fbc5cbe6 100644
--- a/supervisor/shared/usb/usb.c
+++ b/supervisor/shared/usb/usb.c
@@ -30,6 +30,7 @@
 #include "supervisor/background_callback.h"
 #include "supervisor/port.h"
 #include "supervisor/serial.h"
+#include "supervisor/shared/serial.h"
 #include "supervisor/usb.h"
 #include "lib/utils/interrupt_char.h"
 #include "lib/mp-readline/readline.h"
@@ -102,14 +103,16 @@ void usb_irq_handler(void) {
 // tinyusb callbacks
 //--------------------------------------------------------------------+
 
-// Invoked when device is mounted
+// Invoked when device is plugged into a host
 void tud_mount_cb(void) {
     usb_msc_mount();
+    _workflow_active = true;
 }
 
-// Invoked when device is unmounted
+// Invoked when device is unplugged from the host
 void tud_umount_cb(void) {
     usb_msc_umount();
+    _workflow_active = false;
 }
 
 // Invoked when usb bus is suspended
@@ -117,10 +120,12 @@ void tud_umount_cb(void) {
 // USB Specs: Within 7ms, device must draw an average current less than 2.5 mA from bus
 void tud_suspend_cb(bool remote_wakeup_en) {
     _serial_connected = false;
+    _workflow_active = false;
 }
 
 // Invoked when usb bus is resumed
 void tud_resume_cb(void) {
+    _workflow_active = true;
 }
 
 // Invoked when cdc when line state changed e.g connected/disconnected
diff --git a/supervisor/shared/workflow.c b/supervisor/shared/workflow.c
new file mode 100644
index 000000000..adcffb319
--- /dev/null
+++ b/supervisor/shared/workflow.c
@@ -0,0 +1,32 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+// Set by the shared USB code.
+volatile bool _workflow_active;
+
+bool workflow_active(void) {
+    return _workflow_active;
+}
diff --git a/supervisor/shared/workflow.h b/supervisor/shared/workflow.h
new file mode 100644
index 000000000..4a138332a
--- /dev/null
+++ b/supervisor/shared/workflow.h
@@ -0,0 +1,29 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+extern volatile bool _workflow_active;
diff --git a/supervisor/supervisor.mk b/supervisor/supervisor.mk
index e81c51a88..a59e99e3d 100644
--- a/supervisor/supervisor.mk
+++ b/supervisor/supervisor.mk
@@ -75,6 +75,7 @@ else
 		lib/tinyusb/src/class/cdc/cdc_device.c \
 		lib/tinyusb/src/tusb.c \
 		supervisor/shared/serial.c \
+		supervisor/shared/workflow.c \
 		supervisor/usb.c \
 		supervisor/shared/usb/usb_desc.c \
 		supervisor/shared/usb/usb.c \
diff --git a/supervisor/workflow.h b/supervisor/workflow.h
new file mode 100755
index 000000000..4008b83a1
--- /dev/null
+++ b/supervisor/workflow.h
@@ -0,0 +1,30 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+// True when the user could be actively iterating on their code.
+bool workflow_active(void);