Add automatic application start on virtual disk ejection to the Mass Storage class...

[pub/USBasp.git] / Bootloaders / MassStorage / BootloaderMassStorage.c

diff --git a/Bootloaders/MassStorage/BootloaderMassStorage.c b/Bootloaders/MassStorage/BootloaderMassStorage.c
index 28f42b6..1b6eda4 100644 (file)
--- a/Bootloaders/MassStorage/BootloaderMassStorage.c
+++ b/Bootloaders/MassStorage/BootloaderMassStorage.c
@@ -33,6 +33,7 @@
  *  Main source file for the Mass Storage class bootloader. This file contains the complete bootloader logic.
  */
 
+#define  INCLUDE_FROM_BOOTLOADER_MASSSTORAGE_C
 #include "BootloaderMassStorage.h"
 
 /** LUFA Mass Storage Class driver interface configuration and state information. This structure is
@@ -60,7 +61,30 @@ USB_ClassInfo_MS_Device_t Disk_MS_Interface =
                        },
        };
 
+/** Flag to indicate if the bootloader should be running, or should exit and allow the application code to run
+ *  via a soft reset. When cleared, the bootloader will abort, the USB interface will shut down and the application
+ *  started via a forced watchdog reset.
+ */
+bool RunBootloader = true;
+
+/** Magic lock for forced application start. If the HWBE fuse is programmed and BOOTRST is unprogrammed, the bootloader
+ *  will start if the /HWB line of the AVR is held low and the system is reset. However, if the /HWB line is still held
+ *  low when the application attempts to start via a watchdog reset, the bootloader will re-start. If set to the value
+ *  \ref MAGIC_BOOT_KEY the special init function \ref Application_Jump_Check() will force the application to start.
+ */
+uint16_t MagicBootKey ATTR_NO_INIT;
+
+/** Indicates if the bootloader is allowed to exit immediately if \ref RunBootloader is \c false. During shutdown all
+ *  pending commands must be processed before jumping to the user-application, thus this tracks the main program loop
+ *  iterations since a SCSI command from the host was received.
+ */
+static uint8_t TicksSinceLastCommand = 0;
+
 
+/** Special startup routine to check if the bootloader was started via a watchdog reset, and if the magic application
+ *  start key has been loaded into \ref MagicBootKey. If the bootloader started via the watchdog and the key is valid,
+ *  this will force the user application to start via a software jump.
+ */
 void Application_Jump_Check(void)
 {
        bool JumpToApplication = false;
@@ -90,6 +114,13 @@ void Application_Jump_Check(void)
                JTAG_ENABLE();
        #endif
 
+       /* If the reset source was the bootloader and the key is correct, clear it and jump to the application */
+       if ((MCUSR & (1 << WDRF)) && (MagicBootKey == MAGIC_BOOT_KEY))
+       {
+               MagicBootKey      = 0;
+               JumpToApplication = true;
+       }
+
        if (JumpToApplication)
        {
                // cppcheck-suppress constStatement
@@ -107,11 +138,22 @@ int main(void)
        LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
        GlobalInterruptEnable();
 
-       for (;;)
+       while (RunBootloader || TicksSinceLastCommand++ < 0xFF)
        {
                MS_Device_USBTask(&Disk_MS_Interface);
                USB_USBTask();
        }
+
+       /* Disconnect from the host - USB interface will be reset later along with the AVR */
+       USB_Detach();
+
+       /* Unlock the forced application start mode of the bootloader if it is restarted */
+       MagicBootKey = MAGIC_BOOT_KEY;
+
+       /* Enable the watchdog and force a timeout to reset the AVR */
+       wdt_enable(WDTO_250MS);
+
+       for (;;);
 }
 
 /** Configures the board hardware and chip peripherals for the demo's functionality. */
@@ -189,5 +231,8 @@ bool CALLBACK_MS_Device_SCSICommandReceived(USB_ClassInfo_MS_Device_t* const MSI
        CommandSuccess = SCSI_DecodeSCSICommand(MSInterfaceInfo);
        LEDs_SetAllLEDs(LEDMASK_USB_READY);
 
+       /* Signal that a command was processed, must not exit bootloader yet */
+       TicksSinceLastCommand = 0;
+
        return CommandSuccess;
 }