TAP_SD/SI are now forbidden end states.

jtag_add_reset() now returns void streamlining the API

git-svn-id: svn://svn.berlios.de/openocd/trunk@525 b42882b7-edfa-0310-969c-e2dbd0fdcd60

5 files changed, 85 insertions, 158 deletions

diff --git a/src/jtag/bitbang.c b/src/jtag/bitbang.c
index 054faf50..a4e415c2 100644
--- a/src/jtag/bitbang.c
+++ b/src/jtag/bitbang.c
@@ -75,7 +75,7 @@ void bitbang_path_move(pathmove_command_t *cmd)
 {
 	int num_states = cmd->num_states;
 	int state_count;
-	int tms;
+	int tms = 0;
 
 	state_count = 0;
 	while (num_states)
@@ -138,7 +138,6 @@ void bitbang_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size)
 {
 	enum tap_state saved_end_state = end_state;
 	int bit_cnt;
-	int last_bit, last_bit_in;
 	
 	if (!((!ir_scan && (cur_state == TAP_SD)) || (ir_scan && (cur_state == TAP_SI))))
 	{
@@ -151,7 +150,7 @@ void bitbang_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size)
 		bitbang_end_state(saved_end_state);
 	}
 
-	for (bit_cnt = 0; bit_cnt < scan_size - 1; bit_cnt++)
+	for (bit_cnt = 0; bit_cnt < scan_size; bit_cnt++)
 	{
 		/* if we're just reading the scan, but don't care about the output
 		 * default to outputting 'low', this also makes valgrind traces more readable,
@@ -159,69 +158,48 @@ void bitbang_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size)
 		 */ 
 		if ((type != SCAN_IN) && ((buffer[bit_cnt/8] >> (bit_cnt % 8)) & 0x1))
 		{
-			bitbang_interface->write(0, 0, 1);
-			bitbang_interface->write(1, 0, 1);
+			bitbang_interface->write(0, (bit_cnt==scan_size-1) ? 1 : 0, 1);
+			bitbang_interface->write(1, (bit_cnt==scan_size-1) ? 1 : 0, 1);
 		} else {
-			bitbang_interface->write(0, 0, 0);
-			bitbang_interface->write(1, 0, 0);
+			bitbang_interface->write(0, (bit_cnt==scan_size-1) ? 1 : 0, 0);
+			bitbang_interface->write(1, (bit_cnt==scan_size-1) ? 1 : 0, 0);
 		}
 		
 		if (type != SCAN_OUT)
 		{
+			/*
+			TDO should be sampled on the rising edge, and will change 
+			on the falling edge. 
+			
+			Because there is no way to read the signal exactly at the rising edge,
+			read after the rising edge.
+
+			This is plain IEEE 1149 JTAG - nothing specific to the OpenOCD or its JTAG
+			API. 
+			*/
 			if (bitbang_interface->read())
 				buffer[(bit_cnt)/8] |= 1 << ((bit_cnt) % 8);
 			else
 				buffer[(bit_cnt)/8] &= ~(1 << ((bit_cnt) % 8));
 		}
 	}
-
-	if ((type != SCAN_IN) && ((buffer[bit_cnt/8] >> (bit_cnt % 8)) & 0x1))
-		last_bit = 1;
-	else
-		last_bit = 0;
-
-	if ((ir_scan && (end_state == TAP_SI)) ||
-		(!ir_scan && (end_state == TAP_SD)))
-	{
-		bitbang_interface->write(0, 0, last_bit);
-		bitbang_interface->write(1, 0, last_bit);
-
-		if (type != SCAN_OUT)
-			last_bit_in = bitbang_interface->read();
-
-		bitbang_interface->write(0, 0, last_bit);
-	}
+	
+	/* TAP_SD & TAP_SI are illegal end states, so we always transition to the pause
+	 * state which is a legal stable state from which statemove will work.
+	 *  
+	 * Exit1 -> Pause 
+	 */
+	bitbang_interface->write(0, 0, 0);
+	bitbang_interface->write(1, 0, 0);
+	bitbang_interface->write(0, 0, 0);
+	
+	if (ir_scan)
+		cur_state = TAP_PI;
 	else
-	{
-		/* Shift-[ID]R -> Exit1-[ID]R */
-		bitbang_interface->write(0, 1, last_bit);
-		bitbang_interface->write(1, 1, last_bit);
-		
-		if (type != SCAN_OUT)
-			last_bit_in = bitbang_interface->read();
-
-		/* Exit1-[ID]R -> Pause-[ID]R */
-		bitbang_interface->write(0, 0, 0);
-		bitbang_interface->write(1, 0, 0);
-		
-		if (cur_state == TAP_SI)
-			cur_state = TAP_PI;
-		else
-			cur_state = TAP_PD;
-
-		if (cur_state != end_state)
-			bitbang_state_move();
-		else
-			bitbang_interface->write(0, 0, 0);
-	}
-		
-	if (type != SCAN_OUT)
-	{
-		if (last_bit_in)
-			buffer[(bit_cnt)/8] |= 1 << ((bit_cnt) % 8);
-		else
-			buffer[(bit_cnt)/8] &= ~(1 << ((bit_cnt) % 8));
-	}
+		cur_state = TAP_PD;
+	
+	if (cur_state != end_state)
+		bitbang_state_move();
 }
 
 int bitbang_execute_queue(void)
diff --git a/src/jtag/jtag.c b/src/jtag/jtag.c
index 463a1720..8f55ea0b 100644
--- a/src/jtag/jtag.c
+++ b/src/jtag/jtag.c
@@ -225,7 +225,7 @@ int jtag_speed_post_reset = 0;
 void jtag_add_statemove(enum tap_state endstate);
 void jtag_add_pathmove(int num_states, enum tap_state *path);
 void jtag_add_runtest(int num_cycles, enum tap_state endstate);
-int jtag_add_reset(int trst, int srst);
+void jtag_add_reset(int trst, int srst);
 void jtag_add_end_state(enum tap_state endstate);
 void jtag_add_sleep(u32 us);
 int jtag_execute_queue(void);
@@ -411,7 +411,7 @@ static void jtag_prelude(enum tap_state state)
 	jtag_prelude1();
 	
 	if (state != -1)
-		cmd_queue_end_state = state;
+		jtag_add_end_state(state);
 
 	cmd_queue_cur_state = cmd_queue_end_state;
 }
@@ -884,23 +884,18 @@ void jtag_add_runtest(int num_cycles, enum tap_state state)
 		jtag_error=retval;
 }
 
-int jtag_add_reset(int req_trst, int req_srst)
+void jtag_add_reset(int req_trst, int req_srst)
 {
 	int trst_with_tms = 0;
 	int retval;
 	
-	if (req_trst == -1)
-		req_trst = jtag_trst;
-	
-	if (req_srst == -1)
-		req_srst = jtag_srst;
-
 	/* 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_trst == 0))
 	{
-		LOG_WARNING("requested reset would assert trst");
-		return ERROR_JTAG_RESET_WOULD_ASSERT_TRST;
+		LOG_ERROR("BUG: requested reset would assert trst");
+		jtag_error=ERROR_FAIL;
+		return;
 	}
 		
 	/* if TRST pulls SRST, we reset with TAP T-L-R */
@@ -912,8 +907,9 @@ int jtag_add_reset(int req_trst, int req_srst)
 	
 	if (req_srst && !(jtag_reset_config & RESET_HAS_SRST))
 	{
-		LOG_WARNING("requested nSRST assertion, but the current configuration doesn't support this");
-		return ERROR_JTAG_RESET_CANT_SRST;
+		LOG_ERROR("BUG: requested nSRST assertion, but the current configuration doesn't support this");
+		jtag_error=ERROR_FAIL;
+		return;
 	}
 	
 	if (req_trst && !(jtag_reset_config & RESET_HAS_TRST))
@@ -929,7 +925,7 @@ int jtag_add_reset(int req_trst, int req_srst)
 	if (retval!=ERROR_OK)
 	{
 		jtag_error=retval;
-		return retval;
+		return;
 	}
 
 	if (jtag_srst)
@@ -949,7 +945,7 @@ int jtag_add_reset(int req_trst, int req_srst)
 		jtag_add_end_state(TAP_TLR);
 		jtag_add_statemove(TAP_TLR);
 		jtag_call_event_callbacks(JTAG_TRST_ASSERTED);
-		return ERROR_OK;
+		return;
 	}
 	
 	if (jtag_trst)
@@ -970,7 +966,6 @@ int jtag_add_reset(int req_trst, int req_srst)
 		if (jtag_ntrst_delay)
 			jtag_add_sleep(jtag_ntrst_delay * 1000);
 	}
-	return ERROR_OK;
 }
 
 int MINIDRIVER(interface_jtag_add_reset)(int req_trst, int req_srst)
@@ -994,6 +989,10 @@ int MINIDRIVER(interface_jtag_add_reset)(int req_trst, int req_srst)
 void jtag_add_end_state(enum tap_state state)
 {
 	cmd_queue_end_state = state;
+	if ((cmd_queue_end_state == TAP_SD)||(cmd_queue_end_state == TAP_SD))
+	{
+		LOG_ERROR("BUG: TAP_SD/SI can't be end state. Calling code should use a larger scan field");
+	}
 }
 
 int MINIDRIVER(interface_jtag_add_sleep)(u32 us)
diff --git a/src/jtag/jtag.h b/src/jtag/jtag.h
index fca7c350..4d482f06 100644
--- a/src/jtag/jtag.h
+++ b/src/jtag/jtag.h
@@ -245,7 +245,11 @@ extern enum reset_types jtag_reset_config;
 extern int jtag_init(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 */
+/* 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. 
+ */
 extern void jtag_add_ir_scan(int num_fields, scan_field_t *fields, enum tap_state endstate);
 extern int interface_jtag_add_ir_scan(int num_fields, scan_field_t *fields, enum tap_state endstate);
 extern void jtag_add_dr_scan(int num_fields, scan_field_t *fields, enum tap_state endstate);
@@ -294,16 +298,13 @@ extern int interface_jtag_add_pathmove(int num_states, enum tap_state *path);
  */
 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);
-/* If it fails and one of the error messages below are returned, nothing is 
- * added to the queue and jtag_execute() won't return an error code.
- * 
- * ERROR_JTAG_RESET_WOULD_ASSERT_TRST
- * ERROR_JTAG_RESET_CANT_SRST
+/* Invoking jtag_add_reset() with unsupported combinations is
+ * not allowed and constitutes a bug in the calling code.
  * 
- * All other error codes will result in jtag_execute_queue() returning
- * an error.
+ * trst & srst must be 0 or 1. There is no way to 
+ * read the current reset state.
  */
-extern int jtag_add_reset(int trst, int srst);
+extern void jtag_add_reset(int trst, int srst);
 extern int interface_jtag_add_reset(int trst, int srst);
 extern void jtag_add_end_state(enum tap_state endstate);
 extern int interface_jtag_add_end_state(enum tap_state endstate);
@@ -357,8 +358,6 @@ extern int jtag_verify_capture_ir;
 #define ERROR_JTAG_NOT_IMPLEMENTED		(-102)
 #define ERROR_JTAG_TRST_ASSERTED		(-103)
 #define ERROR_JTAG_QUEUE_FAILED			(-104)
-#define ERROR_JTAG_RESET_WOULD_ASSERT_TRST		(-105)
-#define ERROR_JTAG_RESET_CANT_SRST				(-106)
 #define ERROR_JTAG_DEVICE_ERROR			(-107)
 
 
diff --git a/src/target/arm7_9_common.c b/src/target/arm7_9_common.c
index 4b393cc2..4208f38f 100644
--- a/src/target/arm7_9_common.c
+++ b/src/target/arm7_9_common.c
@@ -735,10 +735,14 @@ int arm7_9_poll(target_t *target)
 
 int arm7_9_assert_reset(target_t *target)
 {
-	int retval;
-	
 	LOG_DEBUG("target->state: %s", target_state_strings[target->state]);
 	
+	if (!(jtag_reset_config & RESET_HAS_SRST))
+	{
+		LOG_ERROR("Can't assert SRST");
+		return ERROR_FAIL;
+	}
+	
 	if (target->state == TARGET_HALTED || target->state == TARGET_UNKNOWN)
 	{
 		/* if the target wasn't running, there might be working areas allocated */
@@ -746,46 +750,18 @@ int arm7_9_assert_reset(target_t *target)
 		
 		/* assert SRST and TRST */
 		/* system would get ouf sync if we didn't reset test-logic, too */
-		if ((retval = jtag_add_reset(1, 1)) != ERROR_OK)
-		{
-			if (retval == ERROR_JTAG_RESET_CANT_SRST)
-			{
-				return retval;
-			}
-			else
-			{
-				LOG_ERROR("unknown error");
-				exit(-1);
-			}
-		}
+		jtag_add_reset(1, 1);
+		
 		jtag_add_sleep(5000);
-		if ((retval = jtag_add_reset(0, 1)) != ERROR_OK)
-		{
-			if (retval == ERROR_JTAG_RESET_WOULD_ASSERT_TRST)
-			{
-				retval = jtag_add_reset(1, 1);
-			}
-		}
+		
 	}
-	else
+	
+	if (jtag_reset_config & RESET_SRST_PULLS_TRST)
 	{
-		if ((retval = jtag_add_reset(0, 1)) != ERROR_OK)
-		{
-			if (retval == ERROR_JTAG_RESET_WOULD_ASSERT_TRST)
-			{
-				retval = jtag_add_reset(1, 1);
-			}
-			
-			if (retval == ERROR_JTAG_RESET_CANT_SRST)
-			{
-				return retval;
-			}
-			else if (retval != ERROR_OK)
-			{
-				LOG_ERROR("unknown error");
-				exit(-1);
-			}
-		}
+		jtag_add_reset(1, 1);
+	} else
+	{
+		jtag_add_reset(0, 1);
 	}
 	
 	target->state = TARGET_RESET;
diff --git a/src/target/cortex_m3.c b/src/target/cortex_m3.c
index aba15e7f..aa674745 100644
--- a/src/target/cortex_m3.c
+++ b/src/target/cortex_m3.c
@@ -701,13 +701,18 @@ int cortex_m3_step(struct target_s *target, int current, u32 address, int handle
 
 int cortex_m3_assert_reset(target_t *target)
 {
-	int retval;
 	armv7m_common_t *armv7m = target->arch_info;
 	cortex_m3_common_t *cortex_m3 = armv7m->arch_info;
 	swjdp_common_t *swjdp = &cortex_m3->swjdp_info;
 	
 	LOG_DEBUG("target->state: %s", target_state_strings[target->state]);
 	
+	if (!(jtag_reset_config & RESET_HAS_SRST))
+	{
+		LOG_ERROR("Can't assert SRST");
+		return ERROR_FAIL;
+	}
+
 	ahbap_write_system_u32(swjdp, DCB_DCRDR, 0 );
 	
 	if (target->reset_mode == RESET_RUN)
@@ -727,46 +732,16 @@ int cortex_m3_assert_reset(target_t *target)
 	{
 		/* assert SRST and TRST */
 		/* system would get ouf sync if we didn't reset test-logic, too */
-		if ((retval = jtag_add_reset(1, 1)) != ERROR_OK)
-		{
-			if (retval == ERROR_JTAG_RESET_CANT_SRST)
-			{
-				return retval;
-			}
-			else
-			{
-				LOG_ERROR("unknown error");
-				exit(-1);
-			}
-		}
+		jtag_add_reset(1, 1);
 		jtag_add_sleep(5000);
-		if ((retval = jtag_add_reset(0, 1)) != ERROR_OK)
-		{
-			if (retval == ERROR_JTAG_RESET_WOULD_ASSERT_TRST)
-			{
-				retval = jtag_add_reset(1, 1);
-			}
-		}
 	}
-	else
+
+	if (jtag_reset_config & RESET_SRST_PULLS_TRST)
 	{
-		if ((retval = jtag_add_reset(0, 1)) != ERROR_OK)
-		{
-			if (retval == ERROR_JTAG_RESET_WOULD_ASSERT_TRST)
-			{
-				retval = jtag_add_reset(1, 1);
-			}
-			
-			if (retval == ERROR_JTAG_RESET_CANT_SRST)
-			{
-				return retval;
-			}
-			else if (retval != ERROR_OK)
-			{
-				LOG_ERROR("unknown error");
-				exit(-1);
-			}
-		}
+		jtag_add_reset(1, 1);
+	} else
+	{
+		jtag_add_reset(0, 1);
 	}
 	
 	target->state = TARGET_RESET;