Add a soft_reset function that jumps to bootloader

With the CW-KBD all boxed up, it is impossible to press
the reset button for a firmware upgrade.  This makes it
possible that, as long as we are running a working
firmware, we can jump to the bootloader without taking
the box apart.

Signed-off-by: Vernon Mauery <[email protected]>

Author: vmauery

Makefile

@@ -63,6 +63,11 @@ BOARD =
 #     software delays.
 F_CPU = 16000000
 
+# Boot start address
+#     We need to know the boot start address so we can jump to it on a soft
+#     reset.  This is so we don't have to physically press the reset button
+#     in order to run the bootloader to flash new firmware.
+BOOT_START = 0x7c00
 
 # Input clock frequency.
 #     This will define a symbol, F_CLOCK, in all source code files equal to the 
@@ -181,19 +186,22 @@ CDEFS  = -DF_CPU=$(F_CPU)UL
 CDEFS += -DF_CLOCK=$(F_CLOCK)UL
 CDEFS += -DBOARD=BOARD_$(BOARD)
 CDEFS += $(LUFA_OPTS)
+CDEFS += -DBOOT_START_ADDR=$(BOOT_START)UL
 
 
 # Place -D or -U options here for ASM sources
 ADEFS  = -DF_CPU=$(F_CPU)
 ADEFS += -DF_CLOCK=$(F_CLOCK)UL
 ADEFS += -DBOARD=BOARD_$(BOARD)
 ADEFS += $(LUFA_OPTS)
+ADEFS += -DBOOT_START_ADDR=$(BOOT_START)UL
 
 # Place -D or -U options here for C++ sources
 CPPDEFS  = -DF_CPU=$(F_CPU)UL
 CPPDEFS += -DF_CLOCK=$(F_CLOCK)UL
 CPPDEFS += -DBOARD=BOARD_$(BOARD)
 CPPDEFS += $(LUFA_OPTS)
+CPPDEFS += -DBOOT_START_ADDR=$(BOOT_START)UL
 #CPPDEFS += -D__STDC_LIMIT_MACROS
 #CPPDEFS += -D__STDC_CONSTANT_MACROS
 

cw-kbd.c

@@ -36,6 +36,7 @@
 static void hid_nq(uint8_t c);
 void set_command_mode(bool mode);
 static void exit_command_mode(void);
+void soft_reset(void);
 
 uint8_t hid_in_report_buffer[sizeof(USB_KeyboardReport_Data_t)];
 
@@ -447,6 +448,10 @@ static void inject_string(void) {
 	}
 }
 
+static void clear_led(void) {
+	PORTD &= ~_BV(PD6);
+}
+
 static void set_led(void) {
 	PORTD |= _BV(PD6);
 }
@@ -556,6 +561,9 @@ void command_mode_cb(uint8_t v) {
 			cw_char(':');
 			cw_char(v);
 			break;
+		case 'o': /* jump to reset */
+			soft_reset();
+			break;
 		case 'q': /* quiet mode */
 			cw_set_beeper(!settings_get_beeper());
 			cm_state = command_output;
@@ -874,6 +882,10 @@ void int6_enable(void) {
 	EIMSK |= _BV(INT6);
 }
 
+static void int6_disable(void) {
+	EIMSK &= ~_BV(INT6);
+}
+
 bool command_mode = false;
 void set_command_mode(bool mode) {
 	command_mode = mode;
@@ -932,11 +944,26 @@ void int6_debounce(void) {
 
 /* command mode button */
 ISR(INT6_vect) {
-	EIMSK &= ~_BV(INT6);
+	int6_disable();
 	debug("INT6\n");
 	ms_tick_register(int6_debounce, TICK_INT6_DEBOUNCE, 1);
 }
 
+__attribute__((naked)) void soft_reset(void) {
+	uint8_t mcucr;
+	USB_ShutDown();
+	while (USB_IsInitialized);
+	cli();
+	mcucr = MCUCR | _BV(IVCE) | _BV(IVSEL);
+	MCUCR |= _BV(IVCE);
+	MCUCR = mcucr;
+	cw_fini();
+	int6_disable();
+	clear_led();
+	ms_tick_stop();
+	asm volatile ("jmp %0" : : "i"(BOOT_START_ADDR));
+}
+
 void sw_init(void) {
 	settings_init();
 	ms_tick_init();

cw.c

@@ -1053,3 +1053,9 @@ void cw_init(uint8_t wpm, cw_dq_cb_t cb) {
 	EIMSK |= (_BV(INT1) | _BV(INT0));
 }
 
+void cw_fini(void) {
+	EIMSK &= ~(_BV(INT1) | _BV(INT0));
+	cw_set_dq_callback(NULL);
+	cw_clear_queues();
+	timer3_stop();
+}

cw.h

@@ -85,6 +85,7 @@ didah_queue_t cw_get_left_key(void);
 void cw_init(uint8_t wpm, cw_dq_cb_t cb);
 void cw_set_word_space(bool spaces);
 void cw_set_frequency(uint16_t hz);
+void cw_fini(void);
 void cw_set_keying_mode(keying_mode_t mode);
 void cw_set_dq_callback(cw_dq_cb_t cb);
 void cw_enable_outputs(uint8_t enable_what);