Allow target attachment to timeout and report failure.

This is needed for if the target device is held in reset.

src/arm7tdmi.c

@@ -108,12 +108,12 @@ static void do_nothing(void)
 {
 }
 
-static void arm7_attach(struct target_s *target);
+static bool arm7_attach(struct target_s *target);
 static int arm7_regs_read(struct target_s *target, void *data);
 static int arm7_regs_write(struct target_s *target, const void *data);
 static void arm7_halt_request(struct target_s *target);
 static int arm7_halt_wait(struct target_s *target);
-static void arm7_halt_resume(struct target_s *target, uint8_t step);
+static void arm7_halt_resume(struct target_s *target, bool step);
 
 void arm7tdmi_jtag_handler(jtag_dev_t *dev)
 {
@@ -242,7 +242,7 @@ static int arm7_halt_wait(struct target_s *target)
 	return 1;
 }
 
-static void arm7_halt_resume(struct target_s *target, uint8_t step)
+static void arm7_halt_resume(struct target_s *target, bool step)
 {
 	struct target_arm7_s *t = (struct target_arm7_s *)target;
 
@@ -270,10 +270,15 @@ static void arm7_halt_resume(struct target_s *target, uint8_t step)
 	jtag_dev_write_ir(t->jtag, ARM7_IR_RESTART);
 }
 
-static void arm7_attach(struct target_s *target)
+static bool arm7_attach(struct target_s *target)
 {
+	int tries = 0;
 	target_halt_request(target);
-	while(!target_halt_wait(target));
+	while(!target_halt_wait(target) && --tries)
+		platform_delay(2);
+	if(!tries)
+		return false;
+	return true;
 }
 
 static int arm7_regs_read(struct target_s *target, void *data)

src/cortexm.c

@@ -180,7 +180,7 @@ const struct command_s cortexm_cmd_list[] = {
 #define SIGTRAP 5
 #define SIGSEGV 11
 
-static void cortexm_attach(struct target_s *target);
+static bool cortexm_attach(struct target_s *target);
 static void cortexm_detach(struct target_s *target);
 
 static int cortexm_regs_read(struct target_s *target, void *data);
@@ -333,7 +333,7 @@ cortexm_probe(struct target_s *target)
 	target->halt_request = cortexm_halt_request;
 	target->halt_wait = cortexm_halt_wait;
 	target->halt_resume = cortexm_halt_resume;
-	target->regs_size = sizeof(regnum_cortex_m);	/* XXX: detect FP extension */
+	target->regs_size = sizeof(regnum_cortex_m);
 
 	target_add_commands(target, cortexm_cmd_list, cortexm_driver_str);
 
@@ -371,19 +371,24 @@ cortexm_probe(struct target_s *target)
 	return 0;
 }
 
-static void
+static bool
 cortexm_attach(struct target_s *target)
 {
 	ADIv5_AP_t *ap = adiv5_target_ap(target);
 	struct cortexm_priv *priv = ap->priv;
 	unsigned i;
 	uint32_t r;
+	int tries;
 
 	/* Clear any pending fault condition */
 	target_check_error(target);
 
 	target_halt_request(target);
-	while(!target_halt_wait(target));
+	tries = 10;
+	while(!target_halt_wait(target) && --tries)
+		platform_delay(2);
+	if(!tries)
+		return false;
 
 	/* Request halt on reset */
 	adiv5_ap_mem_write(ap, CORTEXM_DEMCR, priv->demcr);
@@ -423,6 +428,8 @@ cortexm_attach(struct target_s *target)
 	target->set_hw_wp = cortexm_set_hw_wp;
 	target->clear_hw_wp = cortexm_clear_hw_wp;
 	target->check_hw_wp = cortexm_check_hw_wp;
+
+	return true;
 }
 
 static void

src/gdb_main.c

@@ -396,14 +396,15 @@ handle_v_packet(char *packet, int plen)
 		/* Attach to remote target processor */
 		target *t;
 		uint32_t i;
-		for(t = target_list, i = 1; t; t = t->next, i++) 
+		for(t = target_list, i = 1; t; t = t->next, i++)
 			if(i == addr) {
-				cur_target = target_attach(t, 
+				cur_target = target_attach(t,
 						gdb_target_destroy_callback);
-				gdb_putpacketz("T05");
 				break;
 			}
-		if(!cur_target) /* Failed to attach */
+		if(cur_target)
+			gdb_putpacketz("T05");
+		else
 			gdb_putpacketz("E01");
 
 	} else if (!strcmp(packet, "vRun;")) {

src/include/target.h

@@ -120,7 +120,7 @@ struct target_s {
 	target_destroy_callback destroy_callback;
 
 	/* Attach/Detach funcitons */
-	void (*attach)(struct target_s *target);
+	bool (*attach)(struct target_s *target);
 	void (*detach)(struct target_s *target);
 	int (*check_error)(struct target_s *target);
 

src/target.c

@@ -75,7 +75,8 @@ target *target_attach(target *t, target_destroy_callback destroy_cb)
 
 	t->destroy_callback = destroy_cb;
 
-	t->attach(t);
+	if (!t->attach(t))
+		return NULL;
 
 	return t;
 }