disable continous polling while srst is asserted and power dropout is detected

git-svn-id: svn://svn.berlios.de/openocd/trunk@1134 b42882b7-edfa-0310-969c-e2dbd0fdcd60

5 files changed, 436 insertions, 370 deletions

diff --git a/src/ecosboard.c b/src/ecosboard.c
index 4715349..dcde087 100644
--- a/src/ecosboard.c
+++ b/src/ecosboard.c
@@ -1336,90 +1336,7 @@ static void zylinjtag_startNetwork()
 	diag_printf("Web server running\n");
 }
 
-static bool readPowerDropout()
-{
-	cyg_uint32 state;
-	// sample and clear power dropout
-	HAL_WRITE_UINT32(0x08000010, 0x80);
-	HAL_READ_UINT32(0x08000010, state);
-	bool powerDropout;
-	powerDropout = (state & 0x80) != 0;
-	return powerDropout;
-}
 
-bool readSRST()
-{
-	cyg_uint32 state;
-	// sample and clear SRST sensing
-	HAL_WRITE_UINT32(0x08000010, 0x00000040);
-	HAL_READ_UINT32(0x08000010, state);
-	bool srstAsserted;
-	srstAsserted = (state & 0x40) != 0;
-	return srstAsserted;
-}
-
-// every 300ms we check for reset & powerdropout and issue a "reset halt" if
-// so.
-
-
-static int sense_handler(void *priv)
-{
-	struct command_context_s *cmd_ctx;
-	cmd_ctx = (struct command_context_s *) priv;
-
-	static bool prevSrstAsserted = false;
-	static bool prevPowerdropout = false;
-
-	bool powerDropout;
-	powerDropout = readPowerDropout();
-
-	bool powerRestored;
-	powerRestored = prevPowerdropout && !powerDropout;
-	if (powerRestored)
-	{
-		LOG_USER("Sensed power restore.");
-	}
-
-	cyg_tick_count_t current = cyg_current_time();
-	static cyg_tick_count_t lastPower = 0;
-	bool waitMore = lastPower + 200 > current;
-	if (powerDropout && !waitMore)
-	{
-		LOG_USER("Sensed power dropout.");
-		lastPower = current;
-	}
-
-	bool srstAsserted = readSRST();
-
-	bool srstDeasserted;
-	srstDeasserted = prevSrstAsserted && !srstAsserted;
-
-	static cyg_tick_count_t lastSrst = 0;
-	waitMore = lastSrst + 200 > current;
-	if (srstDeasserted && !waitMore)
-	{
-		LOG_USER("Sensed nSRST deasserted");
-		lastSrst = current;
-	}
-
-	if (!prevSrstAsserted && srstAsserted)
-	{
-		LOG_USER("Sensed nSRST asserted");
-	}
-
-	prevSrstAsserted = srstAsserted;
-	prevPowerdropout = powerDropout;
-
-	if (srstDeasserted || powerRestored)
-	{
-		/* Other than logging the event we can't do anything here.
-		 * Issuing a reset is a particularly bad idea as we might
-		 * be inside a reset already.
-		 */
-	}
-
-	return ERROR_OK;
-}
 
 
 
@@ -1999,8 +1916,6 @@ int main(int argc, char *argv[])
 
 	zylinjtag_parse_config_file(cmd_ctx, "/rom/openocd.cfg");
 
-	target_register_timer_callback(sense_handler, 200, 1, cmd_ctx);
-
 	// FIX!!!  Yuk!
 	// diag_printf() is really invoked from many more places than we trust it
 	// not to cause instabilities(e.g. invoking fputc() from an interrupt is *BAD*).
diff --git a/src/jtag/jtag.c b/src/jtag/jtag.c
index f2846d3..d093ee2 100644
--- a/src/jtag/jtag.c
+++ b/src/jtag/jtag.c
@@ -35,15 +35,15 @@
 #include "string.h"
 #include <unistd.h>
 
-/* note that this is not marked as static as it must be available from outside jtag.c for those 
-   that implement the jtag_xxx() minidriver layer 
+/* note that this is not marked as static as it must be available from outside jtag.c for those
+   that implement the jtag_xxx() minidriver layer
 */
-int jtag_error=ERROR_OK; 
+int jtag_error=ERROR_OK;
 
 
 char* tap_state_strings[16] =
 {
-	"tlr", 
+	"tlr",
 	"sds", "cd", "sd", "e1d", "pd", "e2d", "ud",
 	"rti",
 	"sis", "ci", "si", "e1i", "pi", "e2i", "ui"
@@ -66,7 +66,7 @@ static cmd_queue_page_t *cmd_queue_pages = NULL;
  * 3: Pause-DR
  * 4: Shift-IR
  * 5: Pause-IR
- * 
+ *
  * SD->SD and SI->SI have to be caught in interface specific code
  */
 u8 tap_move[6][6] =
@@ -133,11 +133,11 @@ int jtag_verify_capture_ir = 1;
 
 /* how long the OpenOCD should wait before attempting JTAG communication after reset lines deasserted (in ms) */
 int jtag_nsrst_delay = 0; /* default to no nSRST delay */
-int jtag_ntrst_delay = 0; /* default to no nTRST delay */ 
+int jtag_ntrst_delay = 0; /* default to no nTRST delay */
 
 /* maximum number of JTAG devices expected in the chain
  */
-#define JTAG_MAX_CHAIN_SIZE 20 
+#define JTAG_MAX_CHAIN_SIZE 20
 
 /* callbacks to inform high-level handlers about JTAG state changes */
 jtag_event_callback_t *jtag_event_callbacks;
@@ -149,19 +149,19 @@ static int hasKHz = 0;
 
 /* jtag interfaces (parport, FTDI-USB, TI-USB, ...)
  */
- 
+
 #if BUILD_ECOSBOARD == 1
-	extern jtag_interface_t eCosBoard_interface;
+	extern jtag_interface_t zy1000_interface;
 #endif
- 
+
 #if BUILD_PARPORT == 1
 	extern jtag_interface_t parport_interface;
 #endif
-	 
+
 #if BUILD_DUMMY == 1
 	extern jtag_interface_t dummy_interface;
 #endif
-	
+
 #if BUILD_FT2232_FTD2XX == 1
 	extern jtag_interface_t ft2232_interface;
 #endif
@@ -200,7 +200,7 @@ static int hasKHz = 0;
 
 jtag_interface_t *jtag_interfaces[] = {
 #if BUILD_ECOSBOARD == 1
-	&eCosBoard_interface,
+	&zy1000_interface,
 #endif
 #if BUILD_PARPORT == 1
 	&parport_interface,
@@ -276,36 +276,36 @@ int handle_verify_ircapture_command(struct command_context_s *cmd_ctx, char *cmd
 int jtag_register_event_callback(int (*callback)(enum jtag_event event, void *priv), void *priv)
 {
 	jtag_event_callback_t **callbacks_p = &jtag_event_callbacks;
-	
+
 	if (callback == NULL)
 	{
 		return ERROR_INVALID_ARGUMENTS;
 	}
-	
+
 	if (*callbacks_p)
 	{
 		while ((*callbacks_p)->next)
 			callbacks_p = &((*callbacks_p)->next);
 		callbacks_p = &((*callbacks_p)->next);
 	}
-	
+
 	(*callbacks_p) = malloc(sizeof(jtag_event_callback_t));
 	(*callbacks_p)->callback = callback;
 	(*callbacks_p)->priv = priv;
 	(*callbacks_p)->next = NULL;
-	
+
 	return ERROR_OK;
 }
 
 int jtag_unregister_event_callback(int (*callback)(enum jtag_event event, void *priv))
 {
 	jtag_event_callback_t **callbacks_p = &jtag_event_callbacks;
-	
+
 	if (callback == NULL)
 	{
 		return ERROR_INVALID_ARGUMENTS;
 	}
-		
+
 	while (*callbacks_p)
 	{
 		jtag_event_callback_t **next = &((*callbacks_p)->next);
@@ -316,22 +316,22 @@ int jtag_unregister_event_callback(int (*callback)(enum jtag_event event, void *
 		}
 		callbacks_p = next;
 	}
-	
+
 	return ERROR_OK;
 }
 
 int jtag_call_event_callbacks(enum jtag_event event)
 {
 	jtag_event_callback_t *callback = jtag_event_callbacks;
-	
+
 	LOG_DEBUG("jtag event: %s", jtag_event_strings[event]);
-	
+
 	while (callback)
 	{
 		callback->callback(event, callback->priv);
 		callback = callback->next;
 	}
-	
+
 	return ERROR_OK;
 }
 
@@ -342,15 +342,15 @@ int jtag_call_event_callbacks(enum jtag_event event)
 jtag_command_t** jtag_get_last_command_p(void)
 {
 /*	jtag_command_t *cmd = jtag_command_queue;
-	
+
 	if (cmd)
 		while (cmd->next)
 			cmd = cmd->next;
 	else
 		return &jtag_command_queue;
-	
+
 	return &cmd->next;*/
-	
+
 	return last_comand_pointer;
 }
 
@@ -367,7 +367,7 @@ jtag_device_t* jtag_get_device(int num)
 		device = device->next;
 		i++;
 	}
-	
+
 	LOG_ERROR("jtag device number %d not defined", num);
 	exit(-1);
 }
@@ -396,7 +396,7 @@ void* cmd_queue_alloc(size_t size)
 
 	offset = (*p_page)->used;
 	(*p_page)->used += size;
-	
+
 	t=(u8 *)((*p_page)->address);
 	return t + offset;
 }
@@ -432,7 +432,7 @@ static void jtag_prelude1(void)
 static void jtag_prelude(enum tap_state state)
 {
 	jtag_prelude1();
-	
+
 	if (state != -1)
 		jtag_add_end_state(state);
 
@@ -442,16 +442,16 @@ static void jtag_prelude(enum tap_state state)
 void jtag_add_ir_scan(int num_fields, scan_field_t *fields, enum tap_state state)
 {
 	int retval;
-	
+
 	jtag_prelude(state);
-	
+
 	retval=interface_jtag_add_ir_scan(num_fields, fields, cmd_queue_end_state);
 	if (retval!=ERROR_OK)
 		jtag_error=retval;
 }
 
 int MINIDRIVER(interface_jtag_add_ir_scan)(int num_fields, scan_field_t *fields, enum tap_state state)
-{	
+{
 	jtag_command_t **last_cmd;
 	jtag_device_t *device;
 	int i, j;
@@ -459,7 +459,7 @@ int MINIDRIVER(interface_jtag_add_ir_scan)(int num_fields, scan_field_t *fields,
 
 
 	last_cmd = jtag_get_last_command_p();
-	
+
 	/* allocate memory for a new list member */
 	*last_cmd = cmd_queue_alloc(sizeof(jtag_command_t));
 	(*last_cmd)->next = NULL;
@@ -491,7 +491,7 @@ int MINIDRIVER(interface_jtag_add_ir_scan)(int num_fields, scan_field_t *fields,
 				found = 1;
 				(*last_cmd)->cmd.scan->fields[i].out_value = buf_cpy(fields[j].out_value, cmd_queue_alloc(CEIL(scan_size, 8)), scan_size);
 				(*last_cmd)->cmd.scan->fields[i].out_mask = buf_cpy(fields[j].out_mask, cmd_queue_alloc(CEIL(scan_size, 8)), scan_size);
-			
+
 				if (jtag_verify_capture_ir)
 				{
 					if (fields[j].in_handler==NULL)
@@ -501,38 +501,38 @@ int MINIDRIVER(interface_jtag_add_ir_scan)(int num_fields, scan_field_t *fields,
 					{
 						(*last_cmd)->cmd.scan->fields[i].in_handler = fields[j].in_handler;
 						(*last_cmd)->cmd.scan->fields[i].in_handler_priv = fields[j].in_handler_priv;
-						(*last_cmd)->cmd.scan->fields[i].in_check_value = device->expected; 
+						(*last_cmd)->cmd.scan->fields[i].in_check_value = device->expected;
 						(*last_cmd)->cmd.scan->fields[i].in_check_mask = device->expected_mask;
 					}
 				}
-				
+
 				device->bypass = 0;
 				break;
 			}
 		}
-	
+
 		if (!found)
 		{
 			/* if a device isn't listed, set it to BYPASS */
 			(*last_cmd)->cmd.scan->fields[i].out_value = buf_set_ones(cmd_queue_alloc(CEIL(scan_size, 8)), scan_size);
 			(*last_cmd)->cmd.scan->fields[i].out_mask = NULL;
 			device->bypass = 1;
-			
+
 		}
-		
+
 		/* update device information */
 		buf_cpy((*last_cmd)->cmd.scan->fields[i].out_value, jtag_get_device(i)->cur_instr, scan_size);
 	}
-	
+
 	return ERROR_OK;
 }
 
 void jtag_add_plain_ir_scan(int num_fields, scan_field_t *fields, enum tap_state state)
 {
 	int retval;
-	
+
 	jtag_prelude(state);
-	
+
 	retval=interface_jtag_add_plain_ir_scan(num_fields, fields, cmd_queue_end_state);
 	if (retval!=ERROR_OK)
 		jtag_error=retval;
@@ -542,9 +542,9 @@ int MINIDRIVER(interface_jtag_add_plain_ir_scan)(int num_fields, scan_field_t *f
 {
 	int i;
 	jtag_command_t **last_cmd;
-	
+
 	last_cmd = jtag_get_last_command_p();
-	
+
 	/* allocate memory for a new list member */
 	*last_cmd = cmd_queue_alloc(sizeof(jtag_command_t));
 	(*last_cmd)->next = NULL;
@@ -578,7 +578,7 @@ int MINIDRIVER(interface_jtag_add_plain_ir_scan)(int num_fields, scan_field_t *f
 void jtag_add_dr_scan(int num_fields, scan_field_t *fields, enum tap_state state)
 {
 	int retval;
-	
+
 	jtag_prelude(state);
 
 	retval=interface_jtag_add_dr_scan(num_fields, fields, cmd_queue_end_state);
@@ -608,7 +608,7 @@ int MINIDRIVER(interface_jtag_add_dr_scan)(int num_fields, scan_field_t *fields,
 		LOG_ERROR("all devices in bypass");
 		return ERROR_JTAG_DEVICE_ERROR;
 	}
-	
+
 	/* allocate memory for a new list member */
 	*last_cmd = cmd_queue_alloc(sizeof(jtag_command_t));
 	last_comand_pointer = &((*last_cmd)->next);
@@ -621,12 +621,12 @@ int MINIDRIVER(interface_jtag_add_dr_scan)(int num_fields, scan_field_t *fields,
 	(*last_cmd)->cmd.scan->num_fields = num_fields + bypass_devices;
 	(*last_cmd)->cmd.scan->fields = cmd_queue_alloc((num_fields + bypass_devices) * sizeof(scan_field_t));
 	(*last_cmd)->cmd.scan->end_state = state;
-	
+
 	for (i = 0; i < jtag_num_devices; i++)
 	{
 		int found = 0;
 		(*last_cmd)->cmd.scan->fields[field_count].device = i;
-	
+
 		for (j = 0; j < num_fields; j++)
 		{
 			if (i == fields[j].device)
@@ -652,7 +652,7 @@ int MINIDRIVER(interface_jtag_add_dr_scan)(int num_fields, scan_field_t *fields,
 				LOG_ERROR("BUG: no scan data for a device not in BYPASS");
 				exit(-1);
 			}
-#endif	
+#endif
 			/* program the scan field to 1 bit length, and ignore it's value */
 			(*last_cmd)->cmd.scan->fields[field_count].num_bits = 1;
 			(*last_cmd)->cmd.scan->fields[field_count].out_value = NULL;
@@ -678,7 +678,7 @@ int MINIDRIVER(interface_jtag_add_dr_scan)(int num_fields, scan_field_t *fields,
 	return ERROR_OK;
 }
 
-void MINIDRIVER(interface_jtag_add_dr_out)(int device_num, 
+void MINIDRIVER(interface_jtag_add_dr_out)(int device_num,
 		int num_fields,
 		const int *num_bits,
 		const u32 *value,
@@ -698,7 +698,7 @@ void MINIDRIVER(interface_jtag_add_dr_out)(int device_num,
 			bypass_devices++;
 		device = device->next;
 	}
-	
+
 	/* allocate memory for a new list member */
 	*last_cmd = cmd_queue_alloc(sizeof(jtag_command_t));
 	last_comand_pointer = &((*last_cmd)->next);
@@ -711,11 +711,11 @@ void MINIDRIVER(interface_jtag_add_dr_out)(int device_num,
 	(*last_cmd)->cmd.scan->num_fields = num_fields + bypass_devices;
 	(*last_cmd)->cmd.scan->fields = cmd_queue_alloc((num_fields + bypass_devices) * sizeof(scan_field_t));
 	(*last_cmd)->cmd.scan->end_state = end_state;
-	
+
 	for (i = 0; i < jtag_num_devices; i++)
 	{
 		(*last_cmd)->cmd.scan->fields[field_count].device = i;
-	
+
 		if (i == device_num)
 		{
 			int j;
@@ -750,7 +750,7 @@ void MINIDRIVER(interface_jtag_add_dr_out)(int device_num,
 				LOG_ERROR("BUG: no scan data for a device not in BYPASS");
 				exit(-1);
 			}
-#endif	
+#endif
 			/* program the scan field to 1 bit length, and ignore it's value */
 			(*last_cmd)->cmd.scan->fields[field_count].num_bits = 1;
 			(*last_cmd)->cmd.scan->fields[field_count].out_value = NULL;
@@ -767,7 +767,7 @@ void MINIDRIVER(interface_jtag_add_dr_out)(int device_num,
 void jtag_add_plain_dr_scan(int num_fields, scan_field_t *fields, enum tap_state state)
 {
 	int retval;
-	
+
 	jtag_prelude(state);
 
 	retval=interface_jtag_add_plain_dr_scan(num_fields, fields, cmd_queue_end_state);
@@ -779,7 +779,7 @@ int MINIDRIVER(interface_jtag_add_plain_dr_scan)(int num_fields, scan_field_t *f
 {
 	int i;
 	jtag_command_t **last_cmd = jtag_get_last_command_p();
-	
+
 	/* allocate memory for a new list member */
 	*last_cmd = cmd_queue_alloc(sizeof(jtag_command_t));
 	last_comand_pointer = &((*last_cmd)->next);
@@ -792,7 +792,7 @@ int MINIDRIVER(interface_jtag_add_plain_dr_scan)(int num_fields, scan_field_t *f
 	(*last_cmd)->cmd.scan->num_fields = num_fields;
 	(*last_cmd)->cmd.scan->fields = cmd_queue_alloc(num_fields * sizeof(scan_field_t));
 	(*last_cmd)->cmd.scan->end_state = state;
-	
+
 	for (i = 0; i < num_fields; i++)
 	{
 		int num_bits = fields[i].num_bits;
@@ -814,7 +814,7 @@ int MINIDRIVER(interface_jtag_add_plain_dr_scan)(int num_fields, scan_field_t *f
 void jtag_add_tlr(void)
 {
 	jtag_prelude(TAP_TLR);
-	
+
 	int retval;
 	retval=interface_jtag_add_tlr();
 	if (retval!=ERROR_OK)
@@ -825,7 +825,7 @@ int MINIDRIVER(interface_jtag_add_tlr)()
 {
 	enum tap_state state = TAP_TLR;
 	jtag_command_t **last_cmd = jtag_get_last_command_p();
-	
+
 	/* allocate memory for a new list member */
 	*last_cmd = cmd_queue_alloc(sizeof(jtag_command_t));
 	last_comand_pointer = &((*last_cmd)->next);
@@ -834,8 +834,8 @@ int MINIDRIVER(interface_jtag_add_tlr)()
 
 	(*last_cmd)->cmd.statemove = cmd_queue_alloc(sizeof(statemove_command_t));
 	(*last_cmd)->cmd.statemove->end_state = state;
-	
-	
+
+
 	return ERROR_OK;
 }
 
@@ -867,9 +867,9 @@ void jtag_add_pathmove(int num_states, enum tap_state *path)
 		}
 		cur_state = path[i];
 	}
-	
+
 	jtag_prelude1();
-	
+
 
 	retval=interface_jtag_add_pathmove(num_states, path);
 	cmd_queue_cur_state = path[num_states - 1];
@@ -881,7 +881,7 @@ int MINIDRIVER(interface_jtag_add_pathmove)(int num_states, enum tap_state *path
 {
 	jtag_command_t **last_cmd = jtag_get_last_command_p();
 	int i;
-	
+
 	/* allocate memory for a new list member */
 	*last_cmd = cmd_queue_alloc(sizeof(jtag_command_t));
 	last_comand_pointer = &((*last_cmd)->next);
@@ -891,17 +891,17 @@ int MINIDRIVER(interface_jtag_add_pathmove)(int num_states, enum tap_state *path
 	(*last_cmd)->cmd.pathmove = cmd_queue_alloc(sizeof(pathmove_command_t));
 	(*last_cmd)->cmd.pathmove->num_states = num_states;
 	(*last_cmd)->cmd.pathmove->path = cmd_queue_alloc(sizeof(enum tap_state) * num_states);
-	
+
 	for (i = 0; i < num_states; i++)
 		(*last_cmd)->cmd.pathmove->path[i] = path[i];
-	
+
 	return ERROR_OK;
 }
 
 int MINIDRIVER(interface_jtag_add_runtest)(int num_cycles, enum tap_state state)
 {
 	jtag_command_t **last_cmd = jtag_get_last_command_p();
-	
+
 	/* allocate memory for a new list member */
 	*last_cmd = cmd_queue_alloc(sizeof(jtag_command_t));
 	(*last_cmd)->next = NULL;
@@ -911,16 +911,16 @@ int MINIDRIVER(interface_jtag_add_runtest)(int num_cycles, enum tap_state state)
 	(*last_cmd)->cmd.runtest = cmd_queue_alloc(sizeof(runtest_command_t));
 	(*last_cmd)->cmd.runtest->num_cycles = num_cycles;
 	(*last_cmd)->cmd.runtest->end_state = state;
-	
+
 	return ERROR_OK;
 }
 
 void jtag_add_runtest(int num_cycles, enum tap_state state)
 {
 	int retval;
-	
+
 	jtag_prelude(state);
-	
+
 	/* executed by sw or hw fifo */
 	retval=interface_jtag_add_runtest(num_cycles, cmd_queue_end_state);
 	if (retval!=ERROR_OK)
@@ -931,12 +931,12 @@ void jtag_add_reset(int req_tlr_or_trst, int req_srst)
 {
 	int trst_with_tlr = 0;
 	int retval;
-	
+
 	/* FIX!!! there are *many* different cases here. A better
 	 * approach is needed for legal combinations of transitions...
 	 */
 	if ((jtag_reset_config & RESET_HAS_SRST)&&
-			(jtag_reset_config & RESET_HAS_TRST)&& 
+			(jtag_reset_config & RESET_HAS_TRST)&&
 			((jtag_reset_config & RESET_SRST_PULLS_TRST)==0))
 	{
 		if (((req_tlr_or_trst&&!jtag_trst)||
@@ -948,7 +948,7 @@ void jtag_add_reset(int req_tlr_or_trst, int req_srst)
 			//LOG_ERROR("BUG: transition of req_tlr_or_trst and req_srst in the same jtag_add_reset() call is undefined");
 		}
 	}
-	
+
 	/* Make sure that jtag_reset_config allows the requested reset */
 	/* if SRST pulls TRST, we can't fulfill srst == 1 with trst == 0 */
 	if (((jtag_reset_config & RESET_SRST_PULLS_TRST) && (req_srst == 1)) && (!req_tlr_or_trst))
@@ -957,20 +957,20 @@ void jtag_add_reset(int req_tlr_or_trst, int req_srst)
 		jtag_error=ERROR_FAIL;
 		return;
 	}
-		
+
 	/* if TRST pulls SRST, we reset with TAP T-L-R */
 	if (((jtag_reset_config & RESET_TRST_PULLS_SRST) && (req_tlr_or_trst)) && (req_srst == 0))
 	{
 		trst_with_tlr = 1;
 	}
-	
+
 	if (req_srst && !(jtag_reset_config & RESET_HAS_SRST))
 	{
 		LOG_ERROR("BUG: requested SRST assertion, but the current configuration doesn't support this");
 		jtag_error=ERROR_FAIL;
 		return;
 	}
-	
+
 	if (req_tlr_or_trst)
 	{
 		if (!trst_with_tlr && (jtag_reset_config & RESET_HAS_TRST))
@@ -984,7 +984,7 @@ void jtag_add_reset(int req_tlr_or_trst, int req_srst)
 	{
 		jtag_trst = 0;
 	}
-	
+
 	jtag_srst = req_srst;
 
 	retval = interface_jtag_add_reset(jtag_trst, jtag_srst);
@@ -1004,7 +1004,7 @@ void jtag_add_reset(int req_tlr_or_trst, int req_srst)
 		if (jtag_nsrst_delay)
 			jtag_add_sleep(jtag_nsrst_delay * 1000);
 	}
-	
+
 	if (trst_with_tlr)
 	{
 		LOG_DEBUG("JTAG reset with TLR instead of TRST");
@@ -1013,7 +1013,7 @@ void jtag_add_reset(int req_tlr_or_trst, int req_srst)
 		jtag_call_event_callbacks(JTAG_TRST_ASSERTED);
 		return;
 	}
-	
+
 	if (jtag_trst)
 	{
 		/* we just asserted nTRST, so we're now in Test-Logic-Reset,
@@ -1059,7 +1059,7 @@ void jtag_add_end_state(enum tap_state state)
 int MINIDRIVER(interface_jtag_add_sleep)(u32 us)
 {
 	jtag_command_t **last_cmd = jtag_get_last_command_p();
-	
+
 	/* allocate memory for a new list member */
 	*last_cmd = cmd_queue_alloc(sizeof(jtag_command_t));
 	(*last_cmd)->next = NULL;
@@ -1068,7 +1068,7 @@ int MINIDRIVER(interface_jtag_add_sleep)(u32 us)
 
 	(*last_cmd)->cmd.sleep = cmd_queue_alloc(sizeof(sleep_command_t));
 	(*last_cmd)->cmd.sleep->us = us;
-	
+
 	return ERROR_OK;
 }
 
@@ -1099,10 +1099,10 @@ int jtag_build_buffer(scan_command_t *cmd, u8 **buffer)
 {
 	int bit_count = 0;
 	int i;
-	
+
 	bit_count = jtag_scan_size(cmd);
 	*buffer = malloc(CEIL(bit_count, 8));
-	
+
 	bit_count = 0;
 
 	for (i = 0; i < cmd->num_fields; i++)
@@ -1118,7 +1118,7 @@ int jtag_build_buffer(scan_command_t *cmd, u8 **buffer)
 			free(char_buf);
 #endif
 		}
-		
+
 		bit_count += cmd->fields[i].num_bits;
 	}
 
@@ -1130,10 +1130,10 @@ int jtag_read_buffer(u8 *buffer, scan_command_t *cmd)
 	int i;
 	int bit_count = 0;
 	int retval;
-	
+
 	/* we return ERROR_OK, unless a check fails, or a handler reports a problem */
 	retval = ERROR_OK;
-	
+
 	for (i = 0; i < cmd->num_fields; i++)
 	{
 		/* if neither in_value nor in_handler
@@ -1143,7 +1143,7 @@ int jtag_read_buffer(u8 *buffer, scan_command_t *cmd)
 		{
 			int num_bits = cmd->fields[i].num_bits;
 			u8 *captured = buf_set_buf(buffer, bit_count, malloc(CEIL(num_bits, 8)), 0, num_bits);
-			
+
 #ifdef _DEBUG_JTAG_IO_
 			char *char_buf;
 
@@ -1151,11 +1151,11 @@ int jtag_read_buffer(u8 *buffer, scan_command_t *cmd)
 			LOG_DEBUG("fields[%i].in_value: 0x%s", i, char_buf);
 			free(char_buf);
 #endif
-			
+
 			if (cmd->fields[i].in_value)
 			{
 				buf_cpy(captured, cmd->fields[i].in_value, num_bits);
-				
+
 				if (cmd->fields[i].in_handler)
 				{
 					if (cmd->fields[i].in_handler(cmd->fields[i].in_value, cmd->fields[i].in_handler_priv, cmd->fields+i) != ERROR_OK)
@@ -1165,7 +1165,7 @@ int jtag_read_buffer(u8 *buffer, scan_command_t *cmd)
 					}
 				}
 			}
-			
+
 			/* no in_value specified, but a handler takes care of the scanned data */
 			if (cmd->fields[i].in_handler && (!cmd->fields[i].in_value))
 			{
@@ -1191,20 +1191,20 @@ int jtag_check_value(u8 *captured, void *priv, scan_field_t *field)
 {
 	int retval = ERROR_OK;
 	int num_bits = field->num_bits;
-	
+
 	int compare_failed = 0;
-	
+
 	if (field->in_check_mask)
 		compare_failed = buf_cmp_mask(captured, field->in_check_value, field->in_check_mask, num_bits);
 	else
 		compare_failed = buf_cmp(captured, field->in_check_value, num_bits);
-	
+
 	if (compare_failed)
 		{
 		/* An error handler could have caught the failing check
 		 * only report a problem when there wasn't a handler, or if the handler
 		 * acknowledged the error
-		 */ 
+		 */
 		if (compare_failed)
 		{
 			char *captured_char = buf_to_str(captured, (num_bits > 64) ? 64 : num_bits, 16);
@@ -1224,15 +1224,15 @@ int jtag_check_value(u8 *captured, void *priv, scan_field_t *field)
 
 			free(captured_char);
 			free(in_check_value_char);
-			
+
 			retval = ERROR_JTAG_QUEUE_FAILED;
 		}
-		
+
 	}
 	return retval;
 }
 
-/* 
+/*
   set up checking of this field using the in_handler. The values passed in must be valid until
   after jtag_execute() has completed.
  */
@@ -1251,7 +1251,7 @@ enum scan_type jtag_scan_type(scan_command_t *cmd)
 {
 	int i;
 	int type = 0;
-	
+
 	for (i = 0; i < cmd->num_fields; i++)
 	{
 		if (cmd->fields[i].in_value || cmd->fields[i].in_handler)
@@ -1266,15 +1266,15 @@ enum scan_type jtag_scan_type(scan_command_t *cmd)
 int MINIDRIVER(interface_jtag_execute_queue)(void)
 {
 	int retval;
-	
+
 	if (jtag==NULL)
 	{
 		LOG_ERROR("No JTAG interface configured yet. Issue 'init' command in startup scripts before communicating with targets.");
 		return ERROR_FAIL;
 	}
-	
+
 	retval = jtag->execute_queue();
-	
+
 	cmd_queue_free();
 
 	jtag_command_queue = NULL;
@@ -1299,13 +1299,13 @@ int jtag_reset_callback(enum jtag_event event, void *priv)
 	jtag_device_t *device = priv;
 
 	LOG_DEBUG("-");
-	
+
 	if (event == JTAG_TRST_ASSERTED)
 	{
 		buf_set_ones(device->cur_instr, device->ir_length);
 		device->bypass = 1;
 	}
-	
+
 	return ERROR_OK;
 }
 
@@ -1326,7 +1326,7 @@ int jtag_examine_chain(void)
 	int device_count = 0;
 	u8 zero_check = 0x0;
 	u8 one_check = 0xff;
-	
+
 	field.device = 0;
 	field.num_bits = sizeof(idcode_buffer) * 8;
 	field.out_value = idcode_buffer;
@@ -1336,28 +1336,28 @@ int jtag_examine_chain(void)
 	field.in_check_mask = NULL;
 	field.in_handler = NULL;
 	field.in_handler_priv = NULL;
-	
+
 	for (i = 0; i < JTAG_MAX_CHAIN_SIZE; i++)
 	{
 		buf_set_u32(idcode_buffer, i * 32, 32, 0x000000FF);
 	}
-	
+
 	jtag_add_plain_dr_scan(1, &field, TAP_TLR);
 	jtag_execute_queue();
-	
+
 	for (i = 0; i < JTAG_MAX_CHAIN_SIZE * 4; i++)
 	{
 		zero_check |= idcode_buffer[i];
 		one_check &= idcode_buffer[i];
 	}
-	
+
 	/* if there wasn't a single non-zero bit or if all bits were one, the scan isn't valid */
 	if ((zero_check == 0x00) || (one_check == 0xff))
 	{
 		LOG_ERROR("JTAG communication failure, check connection, JTAG interface, target power etc.");
 		return ERROR_JTAG_INIT_FAILED;
 	}
-	
+
 	for (bit_count = 0; bit_count < (JTAG_MAX_CHAIN_SIZE * 32) - 31;)
 	{
 		u32 idcode = buf_get_u32(idcode_buffer, bit_count, 32);
@@ -1366,7 +1366,7 @@ int jtag_examine_chain(void)
 			/* LSB must not be 0, this indicates a device in bypass */
 			LOG_WARNING("Device does not have IDCODE");
 			idcode=0;
-			
+
 			bit_count += 1;
 		}
 		else
@@ -1374,22 +1374,22 @@ int jtag_examine_chain(void)
 			u32 manufacturer;
 			u32 part;
 			u32 version;
-			
+
 			if (idcode == 0x000000FF)
 			{
 				int unexpected=0;
-				/* End of chain (invalid manufacturer ID) 
-				 * 
+				/* End of chain (invalid manufacturer ID)
+				 *
 				 * The JTAG examine is the very first thing that happens
-				 * 
+				 *
 				 * A single JTAG device requires only 64 bits to be read back correctly.
-				 * 
+				 *
 				 * The code below adds a check that the rest of the data scanned (640 bits)
 				 * are all as expected. This helps diagnose/catch problems with the JTAG chain
-				 * 
+				 *
 				 * earlier and gives more helpful/explicit error messages.
 				 */
-				for (bit_count += 32; bit_count < (JTAG_MAX_CHAIN_SIZE * 32) - 31;bit_count += 32) 
+				for (bit_count += 32; bit_count < (JTAG_MAX_CHAIN_SIZE * 32) - 31;bit_count += 32)
 				{
 					idcode = buf_get_u32(idcode_buffer, bit_count, 32);
 					if (unexpected||(idcode != 0x000000FF))
@@ -1398,17 +1398,17 @@ int jtag_examine_chain(void)
 						unexpected = 1;
 					}
 				}
-				
+
 				break;
 			}
-			
+
 			manufacturer = (idcode & 0xffe) >> 1;
 			part = (idcode & 0xffff000) >> 12;
 			version = (idcode & 0xf0000000) >> 28;
 
-			LOG_INFO("JTAG device found: 0x%8.8x (Manufacturer: 0x%3.3x, Part: 0x%4.4x, Version: 0x%1.1x)", 
+			LOG_INFO("JTAG device found: 0x%8.8x (Manufacturer: 0x%3.3x, Part: 0x%4.4x, Version: 0x%1.1x)",
 				idcode, manufacturer, part, version);
-			
+
 			bit_count += 32;
 		}
 		if (device)
@@ -1418,16 +1418,16 @@ int jtag_examine_chain(void)
 		}
 		device_count++;
 	}
-	
+
 	/* see if number of discovered devices matches configuration */
 	if (device_count != jtag_num_devices)
 	{
-		LOG_ERROR("number of discovered devices in JTAG chain (%i) doesn't match configuration (%i)", 
+		LOG_ERROR("number of discovered devices in JTAG chain (%i) doesn't match configuration (%i)",
 				device_count, jtag_num_devices);
 		LOG_ERROR("check the config file and ensure proper JTAG communication (connections, speed, ...)");
 		return ERROR_JTAG_INIT_FAILED;
 	}
-	
+
 	return ERROR_OK;
 }
 
@@ -1438,17 +1438,17 @@ int jtag_validate_chain(void)
 	u8 *ir_test = NULL;
 	scan_field_t field;
 	int chain_pos = 0;
-	
+
 	while (device)
 	{
 		total_ir_length += device->ir_length;
 		device = device->next;
 	}
-	
+
 	total_ir_length += 2;
 	ir_test = malloc(CEIL(total_ir_length, 8));
 	buf_set_ones(ir_test, total_ir_length);
-	
+
 	field.device = 0;
 	field.num_bits = total_ir_length;
 	field.out_value = ir_test;
@@ -1458,10 +1458,10 @@ int jtag_validate_chain(void)
 	field.in_check_mask = NULL;
 	field.in_handler = NULL;
 	field.in_handler_priv = NULL;
-	
+
 	jtag_add_plain_ir_scan(1, &field, TAP_TLR);
 	jtag_execute_queue();
-	
+
 	device = jtag_devices;
 	while (device)
 	{
@@ -1476,7 +1476,7 @@ int jtag_validate_chain(void)
 		chain_pos += device->ir_length;
 		device = device->next;
 	}
-	
+
 	if (buf_get_u32(ir_test, chain_pos, 2) != 0x3)
 	{
 		char *cbuf = buf_to_str(ir_test, total_ir_length, 16);
@@ -1485,9 +1485,9 @@ int jtag_validate_chain(void)
 		free(ir_test);
 		return ERROR_JTAG_INIT_FAILED;
 	}
-	
+
 	free(ir_test);
-	
+
 	return ERROR_OK;
 }
 
@@ -1504,16 +1504,16 @@ jim_jtag_command( Jim_Interp *interp, int argc, Jim_Obj *const *argv )
 		JTAG_CMD_INTERFACE,
 		JTAG_CMD_INIT_RESET,
 	};
-	
+
 	const Jim_Nvp jtag_cmds[] = {
 		{ .name = "interface"     , .value = JTAG_CMD_INTERFACE },
 		{ .name = "arp_init-reset", .value = JTAG_CMD_INIT_RESET },
-		
+
 		{ .name = NULL, .value = -1 },
 	};
 
 	context = Jim_GetAssocData(interp, "context");
-	// go past the command 
+	// go past the command
 	Jim_GetOpt_Setup( &goi, interp, argc-1, argv+1 );
 
 	e = Jim_GetOpt_Nvp( &goi, jtag_cmds, &n );
@@ -1545,7 +1545,7 @@ jim_jtag_command( Jim_Interp *interp, int argc, Jim_Obj *const *argv )
 		}
 		return JIM_OK;
 	}
-		
+
 
 	return JIM_ERR;
 }
@@ -1568,7 +1568,7 @@ int jtag_register_commands(struct command_context_s *cmd_ctx)
 		COMMAND_ANY, "jtag_nsrst_delay <ms> - delay after deasserting srst in ms");
 	register_command(cmd_ctx, NULL, "jtag_ntrst_delay", handle_jtag_ntrst_delay_command,
 		COMMAND_ANY, "jtag_ntrst_delay <ms> - delay after deasserting trst in ms");
-		
+
 	register_command(cmd_ctx, NULL, "scan_chain", handle_scan_chain_command,
 		COMMAND_EXEC, "print current scan chain configuration");
 
@@ -1591,7 +1591,7 @@ int jtag_interface_init(struct command_context_s *cmd_ctx)
 {
 	if (jtag)
 		return ERROR_OK;
-	
+
 	if (!jtag_interface)
 	{
 		/* nothing was previously specified by "interface" command */
@@ -1607,8 +1607,8 @@ int jtag_interface_init(struct command_context_s *cmd_ctx)
 	if (jtag_interface->init() != ERROR_OK)
 		return ERROR_JTAG_INIT_FAILED;
 
-	
-	
+
+
 	jtag = jtag_interface;
 	return ERROR_OK;
 }
@@ -1619,7 +1619,7 @@ static int jtag_init_inner(struct command_context_s *cmd_ctx)
 	int retval;
 
 	LOG_DEBUG("Init JTAG chain");
-	
+
 	device = jtag_devices;
 	jtag_ir_scan_size = 0;
 	jtag_num_devices = 0;
@@ -1629,7 +1629,7 @@ static int jtag_init_inner(struct command_context_s *cmd_ctx)
 		jtag_num_devices++;
 		device = device->next;
 	}
-	
+
 	jtag_add_tlr();
 	if ((retval=jtag_execute_queue())!=ERROR_OK)
 		return retval;
@@ -1639,12 +1639,12 @@ static int jtag_init_inner(struct command_context_s *cmd_ctx)
 	{
 		LOG_ERROR("trying to validate configured JTAG chain anyway...");
 	}
-	
+
 	if (jtag_validate_chain() != ERROR_OK)
 	{
 		LOG_ERROR("Could not validate JTAG chain, continuing anyway...");
 	}
-	
+
 	return ERROR_OK;
 }
 
@@ -1658,19 +1658,19 @@ int jtag_init_reset(struct command_context_s *cmd_ctx)
 	LOG_DEBUG("Trying to bring the JTAG controller to life by asserting TRST / TLR");
 
 	/* Reset can happen after a power cycle.
-	 * 
+	 *
 	 * Ideally we would only assert TRST or run TLR before the target reset.
-	 * 
+	 *
 	 * However w/srst_pulls_trst, trst is asserted together with the target
 	 * reset whether we want it or not.
-	 * 
-	 * NB! Some targets have JTAG circuitry disabled until a 
+	 *
+	 * NB! Some targets have JTAG circuitry disabled until a
 	 * trst & srst has been asserted.
-	 * 
+	 *
 	 * NB! here we assume nsrst/ntrst delay are sufficient!
-	 * 
+	 *
 	 * NB! order matters!!!! srst *can* disconnect JTAG circuitry
-	 * 
+	 *
 	 */
 	jtag_add_reset(1, 0); /* TLR or TRST */
 	if (jtag_reset_config & RESET_HAS_SRST)
@@ -1682,11 +1682,11 @@ int jtag_init_reset(struct command_context_s *cmd_ctx)
 	jtag_add_reset(0, 0);
 	if ((retval = jtag_execute_queue()) != ERROR_OK)
 		return retval;
-	
+
 	/* Check that we can communication on the JTAG chain + eventually we want to
-	 * be able to perform enumeration only after OpenOCD has started 
+	 * be able to perform enumeration only after OpenOCD has started
 	 * telnet and GDB server
-	 * 
+	 *
 	 * That would allow users to more easily perform any magic they need to before
 	 * reset happens.
 	 */
@@ -1714,7 +1714,19 @@ static int default_khz(int khz, int *jtag_speed)
 static int default_speed_div(int speed, int *khz)
 {
 	LOG_ERROR("Translation from jtag_speed to khz not implemented");
-	return ERROR_FAIL;	
+	return ERROR_FAIL;
+}
+
+static int default_power_dropout(int *dropout)
+{
+	*dropout=0; /* by default we can't detect power dropout */
+	return ERROR_OK;
+}
+
+static int default_srst_asserted(int *srst_asserted)
+{
+	*srst_asserted=0; /* by default we can't detect srst asserted */
+	return ERROR_OK;
 }
 
 int handle_interface_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
@@ -1745,7 +1757,7 @@ int handle_interface_command(struct command_context_s *cmd_ctx, char *cmd, char
 			}
 
 			jtag_interface = jtag_interfaces[i];
-			
+
 			if (jtag_interface->khz == NULL)
 			{
 				jtag_interface->khz = default_khz;
@@ -1754,6 +1766,15 @@ int handle_interface_command(struct command_context_s *cmd_ctx, char *cmd, char
 			{
 				jtag_interface->speed_div = default_speed_div;
 			}
+			if (jtag_interface->power_dropout == NULL)
+			{
+				jtag_interface->power_dropout = default_power_dropout;
+			}
+			if (jtag_interface->srst_asserted == NULL)
+			{
+				jtag_interface->srst_asserted = default_srst_asserted;
+			}
+
 			return ERROR_OK;
 		}
 	}
@@ -1796,13 +1817,13 @@ int handle_jtag_device_command(struct command_context_s *cmd_ctx, char *cmd, cha
 	(*last_device_p)->cur_instr = malloc((*last_device_p)->ir_length);
 	(*last_device_p)->bypass = 1;
 	buf_set_ones((*last_device_p)->cur_instr, (*last_device_p)->ir_length);
-	
+
 	(*last_device_p)->next = NULL;
-	
+
 	jtag_register_event_callback(jtag_reset_callback, (*last_device_p));
-	
+
 	jtag_num_devices++;
-	
+
 	return ERROR_OK;
 }
 
@@ -1810,7 +1831,7 @@ int handle_scan_chain_command(struct command_context_s *cmd_ctx, char *cmd, char
 {
 	jtag_device_t *device = jtag_devices;
 	int device_count = 0;
-	
+
 	while (device)
 	{
 		u32 expected, expected_mask, cur_instr;
@@ -1829,7 +1850,7 @@ int handle_reset_config_command(struct command_context_s *cmd_ctx, char *cmd, ch
 {
 	if (argc < 1)
 		return ERROR_COMMAND_SYNTAX_ERROR;
-	
+
 	if (argc >= 1)
 	{
 		if (strcmp(args[0], "none") == 0)
@@ -1847,7 +1868,7 @@ int handle_reset_config_command(struct command_context_s *cmd_ctx, char *cmd, ch
 			return ERROR_INVALID_ARGUMENTS;
 		}
 	}
-	
+
 	if (argc >= 2)
 	{
 		if (strcmp(args[1], "separate") == 0)
@@ -1869,7 +1890,7 @@ int handle_reset_config_command(struct command_context_s *cmd_ctx, char *cmd, ch
 			}
 		}
 	}
-	
+
 	if (argc >= 3)
 	{
 		if (strcmp(args[2], "trst_open_drain") == 0)
@@ -1897,7 +1918,7 @@ int handle_reset_config_command(struct command_context_s *cmd_ctx, char *cmd, ch
 			return ERROR_INVALID_ARGUMENTS;
 		}
 	}
-	
+
 	return ERROR_OK;
 }
 
@@ -1912,7 +1933,7 @@ int handle_jtag_nsrst_delay_command(struct command_context_s *cmd_ctx, char *cmd
 	{
 		jtag_nsrst_delay = strtoul(args[0], NULL, 0);
 	}
-	
+
 	return ERROR_OK;
 }
 
@@ -1927,22 +1948,22 @@ int handle_jtag_ntrst_delay_command(struct command_context_s *cmd_ctx, char *cmd
 	{
 		jtag_ntrst_delay = strtoul(args[0], NULL, 0);
 	}
-	
+
 	return ERROR_OK;
 }
 
 int handle_jtag_speed_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
 {
 	int retval=ERROR_OK;
-	
+
 	if (argc == 1)
 	{
 		LOG_DEBUG("handle jtag speed");
 
 		int cur_speed = 0;
 		cur_speed = jtag_speed = strtoul(args[0], NULL, 0);
-			
-		/* this command can be called during CONFIG, 
+
+		/* this command can be called during CONFIG,
 		 * in which case jtag isn't initialized */
 		if (jtag)
 		{
@@ -1955,7 +1976,7 @@ int handle_jtag_speed_command(struct command_context_s *cmd_ctx, char *cmd, char
 		return ERROR_COMMAND_SYNTAX_ERROR;
 	}
 	command_print(cmd_ctx, "jtag_speed: %d", jtag_speed);
-	
+
 	return retval;
 }
 
@@ -1963,7 +1984,7 @@ int handle_jtag_khz_command(struct command_context_s *cmd_ctx, char *cmd, char *
 {
 	int retval=ERROR_OK;
 	LOG_DEBUG("handle jtag khz");
-	
+
 	if(argc == 1)
 	{
 		speed_khz = strtoul(args[0], NULL, 0);
@@ -1977,9 +1998,9 @@ int handle_jtag_khz_command(struct command_context_s *cmd_ctx, char *cmd, char *
 				speed_khz = 0;
 				return retval;
 			}
-	
+
 			cur_speed = jtag_speed = speed_div1;
-	
+
 			retval=jtag->speed(cur_speed);
 		} else
 		{
@@ -1992,12 +2013,12 @@ int handle_jtag_khz_command(struct command_context_s *cmd_ctx, char *cmd, char *
 		return ERROR_COMMAND_SYNTAX_ERROR;
 	}
 
-	if (jtag!=NULL)	
+	if (jtag!=NULL)
 	{
 		if ((retval=jtag->speed_div(jtag_speed, &speed_khz))!=ERROR_OK)
 			return retval;
 	}
-	
+
 	command_print(cmd_ctx, "jtag_khz: %d", speed_khz);
 	return retval;
 
@@ -2023,7 +2044,7 @@ int handle_endstate_command(struct command_context_s *cmd_ctx, char *cmd, char *
 		}
 	}
 	command_print(cmd_ctx, "current endstate: %s", tap_state_strings[cmd_queue_end_state]);
-	
+
 	return ERROR_OK;
 }
 
@@ -2031,7 +2052,7 @@ int handle_jtag_reset_command(struct command_context_s *cmd_ctx, char *cmd, char
 {
 	int trst = -1;
 	int srst = -1;
-	
+
 	if (argc < 2)
 	{
 		return ERROR_COMMAND_SYNTAX_ERROR;
@@ -2082,14 +2103,14 @@ int handle_irscan_command(struct command_context_s *cmd_ctx, char *cmd, char **a
 {
 	int i;
 	scan_field_t *fields;
-	
+
 	if ((argc < 2) || (argc % 2))
 	{
 		return ERROR_COMMAND_SYNTAX_ERROR;
 	}
 
 	fields = malloc(sizeof(scan_field_t) * argc / 2);
-	
+
 	for (i = 0; i < argc / 2; i++)
 	{
 		int device = strtoul(args[i*2], NULL, 0);
@@ -2158,7 +2179,7 @@ int Jim_Command_drscan(Jim_Interp *interp, int argc, Jim_Obj *const *args)
 
 		Jim_GetLong(interp, args[i], &bits);
 		str = Jim_GetString(args[i+1], &len);
-		
+
 		fields[field_count].device = device;
 		fields[field_count].num_bits = bits;
 		fields[field_count].out_value = malloc(CEIL(bits, 8));
@@ -2197,7 +2218,7 @@ int Jim_Command_drscan(Jim_Interp *interp, int argc, Jim_Obj *const *args)
 	}
 
 	Jim_SetResult(interp, list);
-	
+
 	free(fields);
 
 	return JIM_OK;
@@ -2222,8 +2243,19 @@ int handle_verify_ircapture_command(struct command_context_s *cmd_ctx, char *cmd
 	{
 		return ERROR_COMMAND_SYNTAX_ERROR;
 	}
-	
+
 	command_print(cmd_ctx, "verify Capture-IR is %s", (jtag_verify_capture_ir) ? "enabled": "disabled");
-	
+
 	return ERROR_OK;
 }
+
+
+int jtag_power_dropout(int *dropout)
+{
+	return jtag->power_dropout(dropout);
+}
+
+int jtag_srst_asserted(int *srst_asserted)
+{
+	return jtag->srst_asserted(srst_asserted);
+}
diff --git a/src/jtag/jtag.h b/src/jtag/jtag.h
index d70ec2c..68f52dd 100644
--- a/src/jtag/jtag.h
+++ b/src/jtag/jtag.h
@@ -34,16 +34,16 @@
 #endif
 
 /* Tap States
- * TLR - Test-Logic-Reset, RTI - Run-Test/Idle, 
+ * TLR - Test-Logic-Reset, RTI - Run-Test/Idle,
  * SDS - Select-DR-Scan, CD - Capture-DR, SD - Shift-DR, E1D - Exit1-DR,
  * PD - Pause-DR, E2D - Exit2-DR, UD - Update-DR,
  * SIS - Select-IR-Scan, CI - Capture-IR, SI - Shift-IR, E1I - Exit1-IR,
- * PI - Pause-IR, E2I - Exit2-IR, UI - Update-IR 
+ * PI - Pause-IR, E2I - Exit2-IR, UI - Update-IR
  */
 enum tap_state
 {
-	TAP_TLR = 0x0, TAP_RTI = 0x8, 
-	TAP_SDS = 0x1, TAP_CD = 0x2, TAP_SD = 0x3, TAP_E1D = 0x4, 
+	TAP_TLR = 0x0, TAP_RTI = 0x8,
+	TAP_SDS = 0x1, TAP_CD = 0x2, TAP_SD = 0x3, TAP_E1D = 0x4,
 	TAP_PD = 0x5, TAP_E2D = 0x6, TAP_UD = 0x7,
 	TAP_SIS = 0x9, TAP_CI = 0xa, TAP_SI = 0xb, TAP_E1I = 0xc,
 	TAP_PI = 0xd, TAP_E2I = 0xe, TAP_UI = 0xf
@@ -81,7 +81,7 @@ typedef struct scan_field_s
 	u8 *out_mask;		/* only masked bits care */
 	u8 *in_value;		/* pointer to a 32-bit memory location to take data scanned out */
 	/* in_check_value/mask, in_handler_error_handler, in_handler_priv can be used by the in handler, otherwise they contain garbage  */
-	u8 *in_check_value;	/* used to validate scan results */ 
+	u8 *in_check_value;	/* used to validate scan results */
 	u8 *in_check_mask;	/* check specified bits against check_value */
 	in_handler_t in_handler;	    /* process received buffer using this handler */
 	void *in_handler_priv;	/* additional information for the in_handler */
@@ -187,11 +187,11 @@ enum reset_line_mode
 typedef struct jtag_interface_s
 {
 	char* name;
-	
+
 	/* queued command execution
 	 */
 	int (*execute_queue)(void);
-	
+
 	/* interface initalization
 	 */
 	int (*speed)(int speed);
@@ -199,8 +199,8 @@ typedef struct jtag_interface_s
 	int (*init)(void);
 	int (*quit)(void);
 	/* returns JTAG maxium speed for KHz. 0=RTCK. The function returns
-	a failure if it can't support the KHz/RTCK. 
-	
+	a failure if it can't support the KHz/RTCK.
+
 	WARNING!!!! if RTCK is *slow* then think carefully about
 	whether you actually want to support this in the driver.
 	Many target scripts are written to handle the absence of RTCK
@@ -210,7 +210,25 @@ typedef struct jtag_interface_s
 	/* returns the KHz for the provided JTAG speed. 0=RTCK. The function returns
 	a failure if it can't support the KHz/RTCK. */
 	int (*speed_div)(int speed, int *khz);
-	
+
+	/* Read and clear the power dropout flag. Note that a power dropout
+	   can be transitionary, easily much less than a ms.
+
+	   So to find out if the power is *currently* on, you must invoke
+	   this method twice. Once to clear the power dropout flag and a
+	   second time to read the current state.
+
+	   Currently the default implementation is never to detect power dropout.
+	*/
+	int (*power_dropout)(int *power_dropout);
+	/* Read and clear the srst asserted detection flag.
+	 *
+	 * NB!!!! like power_dropout this does *not* read the current
+	 * state. srst assertion is transitionary and *can* be much
+	 * less than 1ms.
+	 */
+	int (*srst_asserted)(int *srst_asserted);
+
 } jtag_interface_t;
 
 enum jtag_event
@@ -241,10 +259,10 @@ extern int jtag_speed_post_reset;
 
 enum reset_types
 {
-	RESET_NONE = 0x0, 
-	RESET_HAS_TRST = 0x1, 
-	RESET_HAS_SRST = 0x2, 
-	RESET_TRST_AND_SRST = 0x3, 
+	RESET_NONE = 0x0,
+	RESET_HAS_TRST = 0x1,
+	RESET_HAS_SRST = 0x2,
+	RESET_TRST_AND_SRST = 0x3,
 	RESET_SRST_PULLS_TRST = 0x4,
 	RESET_TRST_PULLS_SRST = 0x8,
 	RESET_TRST_OPEN_DRAIN = 0x10,
@@ -253,7 +271,7 @@ enum reset_types
 
 extern enum reset_types jtag_reset_config;
 
-/* initialize interface upon startup. A successful no-op 
+/* initialize interface upon startup. A successful no-op
  * upon subsequent invocations
  */
 extern int jtag_interface_init(struct command_context_s *cmd_ctx);
@@ -266,15 +284,15 @@ extern int jtag_init_reset(struct command_context_s *cmd_ctx);
 extern int jtag_register_commands(struct command_context_s *cmd_ctx);
 
 /* JTAG interface, can be implemented with a software or hardware fifo
- * 
+ *
  * TAP_SD and TAP_SI are illegal end states. TAP_SD/SI as end states
  * can be emulated by using a larger scan.
  *
  * Code that is relatively insensitive to the path(as long
- * as it is JTAG compliant) taken through state machine can use 
- * endstate for jtag_add_xxx_scan(). Otherwise the pause state must be 
- * specified as end state and a subsequent jtag_add_pathmove() must 
- * be issued. 
+ * as it is JTAG compliant) taken through state machine can use
+ * endstate for jtag_add_xxx_scan(). Otherwise the pause state must be
+ * specified as end state and a subsequent jtag_add_pathmove() must
+ * be issued.
  *
  */
 extern void jtag_add_ir_scan(int num_fields, scan_field_t *fields, enum tap_state endstate);
@@ -291,25 +309,25 @@ extern int interface_jtag_add_plain_dr_scan(int num_fields, scan_field_t *fields
 extern void jtag_add_tlr(void);
 extern int interface_jtag_add_tlr(void);
 /* Do not use jtag_add_pathmove() unless you need to, but do use it
- * if you have to. 
+ * if you have to.
  *
  * DANGER! If the target is dependent upon a particular sequence
- * of transitions for things to work correctly(e.g. as a workaround 
- * for an errata that contradicts the JTAG standard), then pathmove 
- * must be used, even if some jtag interfaces happen to use the 
- * desired path. Worse, the jtag interface used for testing a 
- * particular implementation, could happen to use the "desired" 
+ * of transitions for things to work correctly(e.g. as a workaround
+ * for an errata that contradicts the JTAG standard), then pathmove
+ * must be used, even if some jtag interfaces happen to use the
+ * desired path. Worse, the jtag interface used for testing a
+ * particular implementation, could happen to use the "desired"
  * path when transitioning to/from end
  * state.
  *
  * A list of unambigious single clock state transitions, not
  * all drivers can support this, but it is required for e.g.
  * XScale and Xilinx support
- * 
+ *
  * Note! TAP_TLR must not be used in the path!
- * 
- * Note that the first on the list must be reachable 
- * via a single transition from the current state. 
+ *
+ * Note that the first on the list must be reachable
+ * via a single transition from the current state.
  *
  * All drivers are required to implement jtag_add_pathmove().
  * However, if the pathmove sequence can not be precisely
@@ -325,31 +343,31 @@ extern int interface_jtag_add_pathmove(int num_states, enum tap_state *path);
 /* go to TAP_RTI, if we're not already there and cycle
  * precisely num_cycles in the TAP_RTI after which move
  * to the end state, if it is != TAP_RTI
- * 
+ *
  * nb! num_cycles can be 0, in which case the fn will navigate
  * to endstate via TAP_RTI
  */
 extern void jtag_add_runtest(int num_cycles, enum tap_state endstate);
 extern int interface_jtag_add_runtest(int num_cycles, enum tap_state endstate);
 /* A reset of the TAP state machine can be requested.
- * 
- * Whether tms or trst reset is used depends on the capabilities of 
+ *
+ * Whether tms or trst reset is used depends on the capabilities of
  * the target and jtag interface(reset_config  command configures this).
- * 
+ *
  * srst can driver a reset of the TAP state machine and vice
  * versa
- * 
+ *
  * Application code may need to examine value of jtag_reset_config
  * to determine the proper codepath
- * 
+ *
  * DANGER! Even though srst drives trst, trst might not be connected to
  * the interface, and it might actually be *harmful* to assert trst in this case.
- * 
+ *
  * This is why combinations such as "reset_config srst_only srst_pulls_trst"
- * are supported. 
+ * are supported.
  *
  * only req_tlr_or_trst and srst can have a transition for a
- * call as the effects of transitioning both at the "same time" 
+ * call as the effects of transitioning both at the "same time"
  * are undefined, but when srst_pulls_trst or vice versa,
  * then trst & srst *must* be asserted together.
  */
@@ -357,8 +375,8 @@ extern void jtag_add_reset(int req_tlr_or_trst, int srst);
 /* this drives the actual srst and trst pins. srst will always be 0
  * if jtag_reset_config & RESET_SRST_PULLS_TRST != 0 and ditto for
  * trst.
- * 
- * the higher level jtag_add_reset will invoke jtag_add_tlr() if 
+ *
+ * the higher level jtag_add_reset will invoke jtag_add_tlr() if
  * approperiate
  */
 extern int interface_jtag_add_reset(int trst, int srst);
@@ -370,28 +388,31 @@ extern int interface_jtag_add_sleep(u32 us);
 
 
 /*
- * For software FIFO implementations, the queued commands can be executed 
+ * For software FIFO implementations, the queued commands can be executed
  * during this call or earlier. A sw queue might decide to push out
  * some of the jtag_add_xxx() operations once the queue is "big enough".
- * 
- * This fn will return an error code if any of the prior jtag_add_xxx() 
+ *
+ * This fn will return an error code if any of the prior jtag_add_xxx()
  * calls caused a failure, e.g. check failure. Note that it does not
  * matter if the operation was executed *before* jtag_execute_queue(),
- * jtag_execute_queue() will still return an error code. 
- * 
+ * jtag_execute_queue() will still return an error code.
+ *
  * All jtag_add_xxx() calls that have in_handler!=NULL will have been
- * executed when this fn returns, but if what has been queued only 
- * clocks data out, without reading anything back, then JTAG could 
- * be running *after* jtag_execute_queue() returns. The API does 
- * not define a way to flush a hw FIFO that runs *after* 
- * jtag_execute_queue() returns. 
- * 
- * jtag_add_xxx() commands can either be executed immediately or 
- * at some time between the jtag_add_xxx() fn call and jtag_execute_queue().  
+ * executed when this fn returns, but if what has been queued only
+ * clocks data out, without reading anything back, then JTAG could
+ * be running *after* jtag_execute_queue() returns. The API does
+ * not define a way to flush a hw FIFO that runs *after*
+ * jtag_execute_queue() returns.
+ *
+ * jtag_add_xxx() commands can either be executed immediately or
+ * at some time between the jtag_add_xxx() fn call and jtag_execute_queue().
  */
 extern int jtag_execute_queue(void);
 /* can be implemented by hw+sw */
 extern int interface_jtag_execute_queue(void);
+extern int jtag_power_dropout(int *dropout);
+extern int jtag_srst_asserted(int *srst_asserted);
+
 
 /* JTAG support functions */
 extern void jtag_set_check_value(scan_field_t *field, u8 *value,  u8 *mask, error_handler_t *in_error_handler);
@@ -422,27 +443,27 @@ extern int jtag_verify_capture_ir;
 #ifdef HAVE_JTAG_MINIDRIVER_H
 /* Here a #define MINIDRIVER() and an inline version of hw fifo interface_jtag_add_dr_out can be defined */
 #include "jtag_minidriver.h"
-#define MINIDRIVER(a) notused ## a 
+#define MINIDRIVER(a) notused ## a
 #else
 #define MINIDRIVER(a) a
-/* jtag_add_dr_out() is a faster version of jtag_add_dr_scan() 
- * 
+/* jtag_add_dr_out() is a faster version of jtag_add_dr_scan()
+ *
  * Current or end_state can not be TAP_TLR. end_state can be -1
- * 
+ *
  * num_bits[i] is the number of bits to clock out from value[i] LSB first.
- * 
+ *
  * If the device is in bypass, then that is an error condition in
  * the caller code that is not detected by this fn, whereas jtag_add_dr_scan()
  * does detect it. Similarly if the device is not in bypass, data must
- * be passed to it. 
- * 
+ * be passed to it.
+ *
  * If anything fails, then jtag_error will be set and jtag_execute() will
  * return an error. There is no way to determine if there was a failure
  * during this function call.
- * 
+ *
  * Note that this jtag_add_dr_out can be defined as an inline function.
  */
-extern void interface_jtag_add_dr_out(int device, 
+extern void interface_jtag_add_dr_out(int device,
 		int num_fields,
 		const int *num_bits,
 		const u32 *value,
@@ -452,7 +473,7 @@ extern void interface_jtag_add_dr_out(int device,
 
 
 
-static __inline__ void jtag_add_dr_out(int device, 
+static __inline__ void jtag_add_dr_out(int device,
 		int num_fields,
 		const int *num_bits,
 		const u32 *value,
diff --git a/src/jtag/zy1000.c b/src/jtag/zy1000.c
index 5583032..b5ed0aa 100644
--- a/src/jtag/zy1000.c
+++ b/src/jtag/zy1000.c
@@ -39,20 +39,20 @@ extern int jtag_error;
 
 /* low level command set
  */
-int eCosBoard_read(void);
-static void eCosBoard_write(int tck, int tms, int tdi);
-void eCosBoard_reset(int trst, int srst);
+int zy1000_read(void);
+static void zy1000_write(int tck, int tms, int tdi);
+void zy1000_reset(int trst, int srst);
 
 
-int eCosBoard_speed(int speed);
-int eCosBoard_register_commands(struct command_context_s *cmd_ctx);
-int eCosBoard_init(void);
-int eCosBoard_quit(void);
+int zy1000_speed(int speed);
+int zy1000_register_commands(struct command_context_s *cmd_ctx);
+int zy1000_init(void);
+int zy1000_quit(void);
 
 /* interface commands */
-int eCosBoard_handle_eCosBoard_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
+int zy1000_handle_zy1000_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
 
-static int eCosBoard_khz(int khz, int *jtag_speed)
+static int zy1000_khz(int khz, int *jtag_speed)
 {
 	if (khz==0)
 	{
@@ -65,7 +65,7 @@ static int eCosBoard_khz(int khz, int *jtag_speed)
 	return ERROR_OK;
 }
 
-static int eCosBoard_speed_div(int speed, int *khz)
+static int zy1000_speed_div(int speed, int *khz)
 {
 	if (speed==0)
 	{
@@ -79,41 +79,71 @@ static int eCosBoard_speed_div(int speed, int *khz)
 	return ERROR_OK;
 }
 
+static bool readPowerDropout()
+{
+	cyg_uint32 state;
+	// sample and clear power dropout
+	HAL_WRITE_UINT32(0x08000010, 0x80);
+	HAL_READ_UINT32(0x08000010, state);
+	bool powerDropout;
+	powerDropout = (state & 0x80) != 0;
+	return powerDropout;
+}
 
-jtag_interface_t eCosBoard_interface =
+
+static bool readSRST()
+{
+	cyg_uint32 state;
+	// sample and clear SRST sensing
+	HAL_WRITE_UINT32(0x08000010, 0x00000040);
+	HAL_READ_UINT32(0x08000010, state);
+	bool srstAsserted;
+	srstAsserted = (state & 0x40) != 0;
+	return srstAsserted;
+}
+
+static int zy1000_power_dropout(int *dropout)
+{
+	*dropout=readPowerDropout(); /* by default we can't detect power dropout */
+	return ERROR_OK;
+}
+
+
+jtag_interface_t zy1000_interface =
 {
 	.name = "ZY1000",
 	.execute_queue = bitbang_execute_queue,
-	.speed = eCosBoard_speed,
-	.register_commands = eCosBoard_register_commands,
-	.init = eCosBoard_init,
-	.quit = eCosBoard_quit,
-	.khz = eCosBoard_khz,
-	.speed_div = eCosBoard_speed_div,
+	.speed = zy1000_speed,
+	.register_commands = zy1000_register_commands,
+	.init = zy1000_init,
+	.quit = zy1000_quit,
+	.khz = zy1000_khz,
+	.speed_div = zy1000_speed_div,
+	.power_dropout = zy1000_power_dropout,
 };
 
-bitbang_interface_t eCosBoard_bitbang =
+bitbang_interface_t zy1000_bitbang =
 {
-	.read = eCosBoard_read,
-	.write = eCosBoard_write,
-	.reset = eCosBoard_reset
+	.read = zy1000_read,
+	.write = zy1000_write,
+	.reset = zy1000_reset
 };
 
 
 
-static void eCosBoard_write(int tck, int tms, int tdi)
+static void zy1000_write(int tck, int tms, int tdi)
 {
 
 }
 
-int eCosBoard_read(void)
+int zy1000_read(void)
 {
 	return -1;
 }
 
 extern bool readSRST();
 
-void eCosBoard_reset(int trst, int srst)
+void zy1000_reset(int trst, int srst)
 {
 	LOG_DEBUG("zy1000 trst=%d, srst=%d", trst, srst);
 	if(!srst)
@@ -137,7 +167,7 @@ void eCosBoard_reset(int trst, int srst)
 		/* assert reset */
 		ZY1000_POKE(0x08000010, 0x00000002);
 	}
-	
+
 	if (trst||(srst&&(jtag_reset_config & RESET_SRST_PULLS_TRST)))
 	{
 		waitIdle();
@@ -146,7 +176,7 @@ void eCosBoard_reset(int trst, int srst)
 	} else
 	{
 		/* We'll get RCLK failure when we assert TRST, so clear any false positives here */
-		ZY1000_POKE(0x08000014, 0x400);		
+		ZY1000_POKE(0x08000014, 0x400);
 	}
 
 	/* wait for srst to float back up */
@@ -175,7 +205,7 @@ void eCosBoard_reset(int trst, int srst)
 	}
 }
 
-int eCosBoard_speed(int speed)
+int zy1000_speed(int speed)
 {
 	if(speed == 0)
 	{
@@ -199,26 +229,26 @@ int eCosBoard_speed(int speed)
 	return ERROR_OK;
 }
 
-int eCosBoard_register_commands(struct command_context_s *cmd_ctx)
+int zy1000_register_commands(struct command_context_s *cmd_ctx)
 {
 	return ERROR_OK;
 }
 
 
-int eCosBoard_init(void)
+int zy1000_init(void)
 {
 	ZY1000_POKE(0x08000010, 0x30); // Turn on LED1 & LED2
 
 	 /* deassert resets. Important to avoid infinite loop waiting for SRST to deassert */
-	eCosBoard_reset(0, 0);
-	eCosBoard_speed(jtag_speed);
+	zy1000_reset(0, 0);
+	zy1000_speed(jtag_speed);
 
-	bitbang_interface = &eCosBoard_bitbang;
+	bitbang_interface = &zy1000_bitbang;
 
 	return ERROR_OK;
 }
 
-int eCosBoard_quit(void)
+int zy1000_quit(void)
 {
 
 	return ERROR_OK;
@@ -605,7 +635,7 @@ extern int jtag_ntrst_delay;
 
 int interface_jtag_add_reset(int req_trst, int req_srst)
 {
-	eCosBoard_reset(req_trst, req_srst);
+	zy1000_reset(req_trst, req_srst);
 	return ERROR_OK;
 }
 
@@ -635,7 +665,7 @@ int interface_jtag_add_runtest(int num_cycles, enum tap_state state)
 	/* test manual drive code on any target */
 	int tms;
 	u8 tms_scan = TAP_MOVE(t, state);
-	
+
 	for (i = 0; i < 7; i++)
 	{
 		tms = (tms_scan >> i) & 1;
@@ -643,7 +673,7 @@ int interface_jtag_add_runtest(int num_cycles, enum tap_state state)
 		ZY1000_POKE(0x08000028,  tms);
 	}
 	waitIdle();
-	ZY1000_POKE(0x08000020, state);	
+	ZY1000_POKE(0x08000020, state);
 #endif
 
 
diff --git a/src/target/target.c b/src/target/target.c
index 07a6233..30b5c2c 100644
--- a/src/target/target.c
+++ b/src/target/target.c
@@ -1447,6 +1447,71 @@ int handle_working_area_command(struct command_context_s *cmd_ctx, char *cmd, ch
 }
 
 
+// every 300ms we check for reset & powerdropout and issue a "reset halt" if
+// so.
+
+static int powerDropout;
+static int srstAsserted;
+
+static int sense_handler()
+{
+	static int prevSrstAsserted = 0;
+	static int prevPowerdropout = 0;
+
+	int retval;
+	if ((retval=jtag_power_dropout(&powerDropout))!=ERROR_OK)
+		return retval;
+
+	int powerRestored;
+	powerRestored = prevPowerdropout && !powerDropout;
+	if (powerRestored)
+	{
+		LOG_USER("Sensed power restore.");
+	}
+
+	long long current = timeval_ms();
+	static long long lastPower = 0;
+	int waitMore = lastPower + 2000 > current;
+	if (powerDropout && !waitMore)
+	{
+		LOG_USER("Sensed power dropout.");
+		lastPower = current;
+	}
+
+	if ((retval=jtag_srst_asserted(&srstAsserted))!=ERROR_OK)
+		return retval;
+
+	int srstDeasserted;
+	srstDeasserted = prevSrstAsserted && !srstAsserted;
+
+	static long long lastSrst = 0;
+	waitMore = lastSrst + 2000 > current;
+	if (srstDeasserted && !waitMore)
+	{
+		LOG_USER("Sensed nSRST deasserted");
+		lastSrst = current;
+	}
+
+	if (!prevSrstAsserted && srstAsserted)
+	{
+		LOG_USER("Sensed nSRST asserted");
+	}
+
+	prevSrstAsserted = srstAsserted;
+	prevPowerdropout = powerDropout;
+
+	if (srstDeasserted || powerRestored)
+	{
+		/* Other than logging the event we can't do anything here.
+		 * Issuing a reset is a particularly bad idea as we might
+		 * be inside a reset already.
+		 */
+	}
+
+	return ERROR_OK;
+}
+
+
 /* process target state changes */
 int handle_target(void *priv)
 {
@@ -1455,7 +1520,10 @@ int handle_target(void *priv)
 
 	while (target)
 	{
-		if (target_continous_poll)
+		sense_handler();
+
+		/* only poll target if we've got power and srst isn't asserted */
+		if (target_continous_poll&&!powerDropout&&!srstAsserted)
 		{
 			/* polling may fail silently until the target has been examined */
 			if((retval = target_poll(target)) != ERROR_OK)