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

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*).

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,

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
 
 

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)