Warn and block MSC disable if the sd card is busy

lua/settings.lua

@@ -282,10 +282,10 @@ local MassStorageSettings = screen:new {
   createUi = function(self)
     self.menu = SettingsScreen("USB Storage")
     local version = require("version").samd()
-    if tonumber(version) < 2 then
+    if tonumber(version) < 3 then
       self.menu.content:Label {
         w = lvgl.PCT(100),
-        text = "Usb Mass Storage requires a SAMD21 firmware version >=2."
+        text = "Usb Mass Storage requires a SAMD21 firmware version >=3."
       }
       return
     end
@@ -304,6 +304,12 @@ local MassStorageSettings = screen:new {
     enable_container:Label { text = "Enable", flex_grow = 1 }
     local enable_sw = enable_container:Switch {}
 
+    local busy_text = self.menu.content:Label {
+      w = lvgl.PCT(100),
+      text = "USB is currently busy. Do not unplug or remove the SD card.",
+      long_mode = lvgl.LABEL.LONG_WRAP,
+    }
+
     local bind_switch = function()
       if usb.msc_enabled:get() then
         enable_sw:add_state(lvgl.STATE.CHECKED)
@@ -313,12 +319,21 @@ local MassStorageSettings = screen:new {
     end
 
     enable_sw:onevent(lvgl.EVENT.VALUE_CHANGED, function()
-      usb.msc_enabled:set(enable_sw:enabled())
+      if not usb.msc_busy:get() then
+        usb.msc_enabled:set(enable_sw:enabled())
+      end
       bind_switch()
     end)
 
     self.bindings = {
       usb.msc_enabled:bind(bind_switch),
+      usb.msc_busy:bind(function(busy)
+        if busy then
+          busy_text:clear_flag(lvgl.FLAG.HIDDEN)
+        else
+          busy_text:add_flag(lvgl.FLAG.HIDDEN)
+        end
+      end)
     }
   end,
   canPop = function()

src/drivers/include/samd.hpp

@@ -48,8 +48,8 @@ class Samd {
     // There is a compatible usb host attached, but USB MSC is not currently
     // in use by the SAMD.
     kAttachedIdle,
-    // The SAMD is currently exposing the SD card via USB MSC.
-    kAttachedMounted,
+    // The SAMD is currently writing to the SD card via USB MSC.
+    kAttachedBusy,
   };
 
   auto GetUsbStatus() -> UsbStatus;

src/drivers/samd.cpp

@@ -113,7 +113,7 @@ auto Samd::UpdateUsbStatus() -> void {
     usb_status_ = UsbStatus::kDetached;
   }
   usb_status_ =
-      (raw_res & 0b10) ? UsbStatus::kAttachedMounted : UsbStatus::kAttachedIdle;
+      (raw_res & 0b10) ? UsbStatus::kAttachedBusy : UsbStatus::kAttachedIdle;
 }
 
 auto Samd::ResetToFlashSamd() -> void {

src/system_fsm/include/system_events.hpp

@@ -12,6 +12,7 @@
 #include "bluetooth_types.hpp"
 #include "database.hpp"
 #include "haptics.hpp"
+#include "samd.hpp"
 #include "service_locator.hpp"
 #include "tinyfsm.hpp"
 
@@ -56,6 +57,9 @@ struct SdDetectChanged : tinyfsm::Event {
 struct SamdUsbMscChanged : tinyfsm::Event {
   bool en;
 };
+struct SamdUsbStatusChanged : tinyfsm::Event {
+  drivers::Samd::UsbStatus new_status;
+};
 
 struct BatteryStateChanged : tinyfsm::Event {
   battery::Battery::BatteryState new_state;

src/system_fsm/system_fsm.cpp

@@ -88,7 +88,7 @@ void SystemState::react(const internal::SamdInterrupt&) {
     sServices->battery().Update();
   }
   if (usb_status != prev_usb_status) {
-    ESP_LOGI(kTag, "usb status changed");
+    events::Ui().Dispatch(SamdUsbStatusChanged{.new_status = usb_status});
   }
 }
 

src/ui/include/ui_fsm.hpp

@@ -65,6 +65,7 @@ class UiState : public tinyfsm::Fsm<UiState> {
   void react(const audio::VolumeLimitChanged&);
 
   void react(const system_fsm::KeyLockChanged&);
+  void react(const system_fsm::SamdUsbStatusChanged&);
 
   void react(const internal::DismissAlerts&);
   void react(const internal::ControlSchemeChanged&);
@@ -133,6 +134,7 @@ class UiState : public tinyfsm::Fsm<UiState> {
   static lua::Property sDatabaseAutoUpdate;
 
   static lua::Property sUsbMassStorageEnabled;
+  static lua::Property sUsbMassStorageBusy;
 };
 
 namespace states {

src/ui/ui_fsm.cpp

@@ -43,6 +43,7 @@
 #include "nvs.hpp"
 #include "property.hpp"
 #include "relative_wheel.hpp"
+#include "samd.hpp"
 #include "screen.hpp"
 #include "screen_lua.hpp"
 #include "screen_splash.hpp"
@@ -302,6 +303,8 @@ lua::Property UiState::sUsbMassStorageEnabled{
       return true;
     }};
 
+lua::Property UiState::sUsbMassStorageBusy{false};
+
 auto UiState::InitBootSplash(drivers::IGpios& gpios, drivers::NvsStorage& nvs)
     -> bool {
   // Init LVGL first, since the display driver registers itself with LVGL.
@@ -360,6 +363,11 @@ void UiState::react(const system_fsm::KeyLockChanged& ev) {
   sLockSwitch.Update(ev.locking);
 }
 
+void UiState::react(const system_fsm::SamdUsbStatusChanged& ev) {
+  sUsbMassStorageBusy.Update(ev.new_status ==
+                             drivers::Samd::UsbStatus::kAttachedBusy);
+}
+
 void UiState::react(const internal::ControlSchemeChanged&) {
   if (!sInput) {
     return;
@@ -573,6 +581,7 @@ void Lua::entry() {
     registry.AddPropertyModule("usb",
                                {
                                    {"msc_enabled", &sUsbMassStorageEnabled},
+                                   {"msc_busy", &sUsbMassStorageBusy},
                                });
 
     sDatabaseAutoUpdate.Update(sServices->nvs().DbAutoIndex());