ARM DPM: share debug reason logic

No point in both ARM11 and Cortex-A8 having private copies
of the logic sorting out e.g. DBG_REASON_WATCHPOINT.

Add and use a shared routine for this ... there's actually
a bunch more debug entry logic that could be shared, this
is just a start on that.  Note that this routine fixes a
bug observed in the ARM11 code, where some abort mode quirks
were displayed as being an unknown debug reason; and also
silences needless ARM11 chatter.

Likewise with private copies of DSCR ... add one to the DPM
struct.  Save it as part of setting DBG_REASON_* so later
patches can switch over to using that copy.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

src/target/arm11.c

@@ -83,8 +83,7 @@ static int arm11_check_init(struct arm11_common *arm11)
 			  */
 
 			arm11->arm.target->state = TARGET_HALTED;
-			arm11->arm.target->debug_reason =
-					arm11_get_DSCR_debug_reason(arm11->dscr);
+			arm_dpm_report_dscr(arm11->arm.dpm, arm11->dscr);
 		}
 		else
 		{
@@ -108,8 +107,7 @@ static int arm11_debug_entry(struct arm11_common *arm11)
 	int retval;
 
 	arm11->arm.target->state = TARGET_HALTED;
-	arm11->arm.target->debug_reason =
-			arm11_get_DSCR_debug_reason(arm11->dscr);
+	arm_dpm_report_dscr(arm11->arm.dpm, arm11->dscr);
 
 	/* REVISIT entire cache should already be invalid !!! */
 	register_cache_invalidate(arm11->arm.core_cache);
@@ -551,20 +549,12 @@ static int arm11_resume(struct target *target, int current,
 		i++;
 	}
 
+	target->debug_reason = DBG_REASON_NOTHALTED;
 	if (!debug_execution)
-	{
-		target->state			= TARGET_RUNNING;
-		target->debug_reason	= DBG_REASON_NOTHALTED;
-
-		CHECK_RETVAL(target_call_event_callbacks(target, TARGET_EVENT_RESUMED));
-	}
+		target->state = TARGET_RUNNING;
 	else
-	{
-		target->state			= TARGET_DEBUG_RUNNING;
-		target->debug_reason	= DBG_REASON_NOTHALTED;
-
-		CHECK_RETVAL(target_call_event_callbacks(target, TARGET_EVENT_RESUMED));
-	}
+		target->state = TARGET_DEBUG_RUNNING;
+	CHECK_RETVAL(target_call_event_callbacks(target, TARGET_EVENT_RESUMED));
 
 	return ERROR_OK;
 }
@@ -728,7 +718,7 @@ static int arm11_step(struct target *target, int current,
 
 	}
 
-	target->debug_reason	= DBG_REASON_SINGLESTEP;
+	target->debug_reason = DBG_REASON_SINGLESTEP;
 
 	CHECK_RETVAL(target_call_event_callbacks(target, TARGET_EVENT_HALTED));
 

src/target/arm11.h

@@ -94,18 +94,6 @@ enum arm11_instructions
 	ARM11_BYPASS    = 0x1F,
 };
 
-enum arm11_dscr
-{
-
-	ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_MASK					= 0x0F << 2,
-	ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_HALT					= 0x00 << 2,
-	ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_BREAKPOINT				= 0x01 << 2,
-	ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_WATCHPOINT				= 0x02 << 2,
-	ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_BKPT_INSTRUCTION		= 0x03 << 2,
-	ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_EDBGRQ					= 0x04 << 2,
-	ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_VECTOR_CATCH			= 0x05 << 2,
-};
-
 enum arm11_sc7
 {
 	ARM11_SC7_NULL				= 0,

src/target/arm11_dbgtap.c

@@ -288,50 +288,6 @@ int arm11_write_DSCR(struct arm11_common * arm11, uint32_t dscr)
 	return ERROR_OK;
 }
 
-
-
-/** Get the debug reason from Debug Status and Control Register (DSCR)
- *
- * \param dscr		DSCR value to analyze
- * \return			Debug reason
- *
- */
-enum target_debug_reason arm11_get_DSCR_debug_reason(uint32_t dscr)
-{
-	switch (dscr & ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_MASK)
-	{
-	case ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_HALT:
-		LOG_INFO("Debug entry: JTAG HALT");
-		return DBG_REASON_DBGRQ;
-
-	case ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_BREAKPOINT:
-		LOG_INFO("Debug entry: breakpoint");
-		return DBG_REASON_BREAKPOINT;
-
-	case ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_WATCHPOINT:
-		LOG_INFO("Debug entry: watchpoint");
-		return DBG_REASON_WATCHPOINT;
-
-	case ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_BKPT_INSTRUCTION:
-		LOG_INFO("Debug entry: BKPT instruction");
-		return DBG_REASON_BREAKPOINT;
-
-	case ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_EDBGRQ:
-		LOG_INFO("Debug entry: EDBGRQ signal");
-		return DBG_REASON_DBGRQ;
-
-	case ARM11_DSCR_METHOD_OF_DEBUG_ENTRY_VECTOR_CATCH:
-		LOG_INFO("Debug entry: VCR vector catch");
-		return DBG_REASON_BREAKPOINT;
-
-	default:
-		LOG_INFO("Debug entry: unknown");
-		return DBG_REASON_DBGRQ;
-	}
-};
-
-
-
 /** Prepare the stage for ITR/DTR operations
  * from the arm11_run_instr... group of functions.
  *

src/target/arm11_dbgtap.h

@@ -14,8 +14,6 @@ int arm11_add_debug_SCAN_N(struct arm11_common *arm11,
 int arm11_read_DSCR(struct arm11_common *arm11);
 int arm11_write_DSCR(struct arm11_common *arm11, uint32_t dscr);
 
-enum target_debug_reason arm11_get_DSCR_debug_reason(uint32_t dscr);
-
 int arm11_run_instr_data_prepare(struct arm11_common *arm11);
 int arm11_run_instr_data_finish(struct arm11_common *arm11);
 int arm11_run_instr_no_data1(struct arm11_common *arm11, uint32_t opcode);

src/target/arm_dpm.c

@@ -755,6 +755,42 @@ void arm_dpm_report_wfar(struct arm_dpm *dpm, uint32_t addr)
 
 /*----------------------------------------------------------------------*/
 
+/*
+ * Other debug and support utilities
+ */
+
+void arm_dpm_report_dscr(struct arm_dpm *dpm, uint32_t dscr)
+{
+	struct target *target = dpm->arm->target;
+
+	dpm->dscr = dscr;
+
+	/* Examine debug reason */
+	switch (DSCR_ENTRY(dscr)) {
+	case 6:		/* Data abort (v6 only) */
+	case 7:		/* Prefetch abort (v6 only) */
+		/* FALL THROUGH -- assume a v6 core in abort mode */
+	case 0:		/* HALT request from debugger */
+	case 4:		/* EDBGRQ */
+		target->debug_reason = DBG_REASON_DBGRQ;
+		break;
+	case 1:		/* HW breakpoint */
+	case 3:		/* SW BKPT */
+	case 5:		/* vector catch */
+		target->debug_reason = DBG_REASON_BREAKPOINT;
+		break;
+	case 2:		/* asynch watchpoint */
+	case 10:	/* precise watchpoint */
+		target->debug_reason = DBG_REASON_WATCHPOINT;
+		break;
+	default:
+		target->debug_reason = DBG_REASON_UNDEFINED;
+		break;
+	}
+}
+
+/*----------------------------------------------------------------------*/
+
 /*
  * Setup and management support.
  */

src/target/arm_dpm.h

@@ -125,6 +125,9 @@ struct arm_dpm {
 	/** Address of the instruction which triggered a watchpoint. */
 	uint32_t wp_pc;
 
+	/** Recent value of DSCR. */
+	uint32_t dscr;
+
 	// FIXME -- read/write DCSR methods and symbols
 };
 
@@ -151,4 +154,6 @@ void arm_dpm_report_wfar(struct arm_dpm *, uint32_t wfar);
 
 #define DSCR_ENTRY(dscr) (((dscr) >> 2) & 0xf)
 
+void arm_dpm_report_dscr(struct arm_dpm *dpm, uint32_t dcsr);
+
 #endif /* __ARM_DPM_H */

src/target/cortex_a8.c

@@ -782,7 +782,7 @@ static int cortex_a8_resume(struct target *target, int current,
 static int cortex_a8_debug_entry(struct target *target)
 {
 	int i;
-	uint32_t regfile[16], wfar, cpsr, dscr;
+	uint32_t regfile[16], cpsr, dscr;
 	int retval = ERROR_OK;
 	struct working_area *regfile_working_area = NULL;
 	struct cortex_a8_common *cortex_a8 = target_to_cortex_a8(target);
@@ -793,6 +793,7 @@ static int cortex_a8_debug_entry(struct target *target)
 
 	LOG_DEBUG("dscr = 0x%08" PRIx32, cortex_a8->cpudbg_dscr);
 
+	/* REVISIT surely we should not re-read DSCR !! */
 	mem_ap_read_atomic_u32(swjdp,
 				armv7a->debug_base + CPUDBG_DSCR, &dscr);
 
@@ -807,30 +808,16 @@ static int cortex_a8_debug_entry(struct target *target)
 			armv7a->debug_base + CPUDBG_DSCR, dscr);
 
 	/* Examine debug reason */
-	switch (DSCR_ENTRY(cortex_a8->cpudbg_dscr))
-	{
-		case 0:		/* DRCR[0] write */
-		case 4:		/* EDBGRQ */
-			target->debug_reason = DBG_REASON_DBGRQ;
-			break;
-		case 1:		/* HW breakpoint */
-		case 3:		/* SW BKPT */
-		case 5:		/* vector catch */
-			target->debug_reason = DBG_REASON_BREAKPOINT;
-			break;
-		case 2:		/* asynch watchpoint */
-		case 10:	/* precise watchpoint */
-			target->debug_reason = DBG_REASON_WATCHPOINT;
-
-			/* save address of faulting instruction */
-			retval = mem_ap_read_atomic_u32(swjdp,
-					armv7a->debug_base + CPUDBG_WFAR,
-					&wfar);
-			arm_dpm_report_wfar(&armv7a->dpm, wfar);
-			break;
-		default:
-			target->debug_reason = DBG_REASON_UNDEFINED;
-			break;
+	arm_dpm_report_dscr(&armv7a->dpm, cortex_a8->cpudbg_dscr);
+
+	/* save address of instruction that triggered the watchpoint? */
+	if (target->debug_reason == DBG_REASON_WATCHPOINT) {
+		uint32_t wfar;
+
+		retval = mem_ap_read_atomic_u32(swjdp,
+				armv7a->debug_base + CPUDBG_WFAR,
+				&wfar);
+		arm_dpm_report_wfar(&armv7a->dpm, wfar);
 	}
 
 	/* REVISIT fast_reg_read is never set ... */