5 files changed, 27 insertions, 8 deletions
diff --git a/src/flash/arm_nandio.c b/src/flash/arm_nandio.c
index fb501e56..8087221a 100644
--- a/src/flash/arm_nandio.c
+++ b/src/flash/arm_nandio.c
@@ -33,7 +33,6 @@
  * For now this only supports ARMv4 and ARMv5 cores.
  *
  * Enhancements to target_run_algorithm() could enable:
- *   - faster writes: on ARMv5+ don't setup/teardown hardware breakpoint
  *   - ARMv6 and ARMv7 cores in ARM mode
  *
  * Different code fragments could handle:
@@ -44,8 +43,10 @@ int arm_nandwrite(struct arm_nand_data *nand, uint8_t *data, int size)
 {
 	target_t		*target = nand->target;
 	armv4_5_algorithm_t	algo;
+	armv4_5_common_t	*armv4_5 = target->arch_info;
 	reg_param_t		reg_params[3];
 	uint32_t		target_buf;
+	uint32_t		exit = 0;
 	int			retval;
 
 	/* Inputs:
@@ -112,11 +113,13 @@ int arm_nandwrite(struct arm_nand_data *nand, uint8_t *data, int size)
 	buf_set_u32(reg_params[1].value, 0, 32, target_buf);
 	buf_set_u32(reg_params[2].value, 0, 32, size);
 
+	/* armv4 must exit using a hardware breakpoint */
+	if (armv4_5->is_armv4)
+		exit = nand->copy_area->address + sizeof(code) - 4;
+
 	/* use alg to write data from work area to NAND chip */
 	retval = target_run_algorithm(target, 0, NULL, 3, reg_params,
-			nand->copy_area->address,
-			nand->copy_area->address + sizeof(code) - 4,
-			1000, &algo);
+			nand->copy_area->address, exit, 1000, &algo);
 	if (retval != ERROR_OK)
 		LOG_ERROR("error executing hosted NAND write");
 
diff --git a/src/target/arm7tdmi.c b/src/target/arm7tdmi.c
index 929ba1d5..0e978c24 100644
--- a/src/target/arm7tdmi.c
+++ b/src/target/arm7tdmi.c
@@ -828,6 +828,7 @@ int arm7tdmi_target_create(struct target_s *target, Jim_Interp *interp)
 
 	arm7tdmi = calloc(1,sizeof(arm7tdmi_common_t));
 	arm7tdmi_init_arch_info(target, arm7tdmi, target->tap);
+	arm7tdmi->arm7_9_common.armv4_5_common.is_armv4 = true;
 
 	return ERROR_OK;
 }
diff --git a/src/target/arm9tdmi.c b/src/target/arm9tdmi.c
index 8cbc3423..2d2e47f1 100644
--- a/src/target/arm9tdmi.c
+++ b/src/target/arm9tdmi.c
@@ -956,6 +956,7 @@ int arm9tdmi_target_create(struct target_s *target, Jim_Interp *interp)
 	arm9tdmi_common_t *arm9tdmi = calloc(1,sizeof(arm9tdmi_common_t));
 
 	arm9tdmi_init_arch_info(target, arm9tdmi, target->tap);
+	arm9tdmi->arm7_9_common.armv4_5_common.is_armv4 = true;
 
 	return ERROR_OK;
 }
diff --git a/src/target/armv4_5.c b/src/target/armv4_5.c
index 9f9aa2f5..eedbc702 100644
--- a/src/target/armv4_5.c
+++ b/src/target/armv4_5.c
@@ -532,7 +532,10 @@ static int armv4_5_run_algorithm_completion(struct target_s *target, uint32_t ex
 		}
 		return ERROR_TARGET_TIMEOUT;
 	}
-	if (buf_get_u32(armv4_5->core_cache->reg_list[15].value, 0, 32) != exit_point)
+
+	/* fast exit: ARMv5+ code can use BKPT */
+	if (exit_point && buf_get_u32(armv4_5->core_cache->reg_list[15].value,
+				0, 32) != exit_point)
 	{
 		LOG_WARNING("target reentered debug state, but not at the desired exit point: 0x%4.4" PRIx32 "",
 			buf_get_u32(armv4_5->core_cache->reg_list[15].value, 0, 32));
@@ -570,6 +573,13 @@ int armv4_5_run_algorithm_inner(struct target_s *target, int num_mem_params, mem
 	if (armv4_5_mode_to_number(armv4_5->core_mode)==-1)
 		return ERROR_FAIL;
 
+	/* armv5 and later can terminate with BKPT instruction; less overhead */
+	if (!exit_point && armv4_5->is_armv4)
+	{
+		LOG_ERROR("ARMv4 target needs HW breakpoint location");
+		return ERROR_FAIL;
+	}
+
 	for (i = 0; i <= 16; i++)
 	{
 		if (!ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5_algorithm_info->core_mode, i).valid)
@@ -626,9 +636,11 @@ int armv4_5_run_algorithm_inner(struct target_s *target, int num_mem_params, mem
 		armv4_5->core_cache->reg_list[ARMV4_5_CPSR].valid = 1;
 	}
 
-	if ((retval = breakpoint_add(target, exit_point, exit_breakpoint_size, BKPT_HARD)) != ERROR_OK)
+	/* terminate using a hardware or (ARMv5+) software breakpoint */
+	if (exit_point && (retval = breakpoint_add(target, exit_point,
+				exit_breakpoint_size, BKPT_HARD)) != ERROR_OK)
 	{
-		LOG_ERROR("can't add breakpoint to finish algorithm execution");
+		LOG_ERROR("can't add HW breakpoint to terminate algorithm");
 		return ERROR_TARGET_FAILURE;
 	}
 
@@ -639,7 +651,8 @@ int armv4_5_run_algorithm_inner(struct target_s *target, int num_mem_params, mem
 	int retvaltemp;
 	retval = run_it(target, exit_point, timeout_ms, arch_info);
 
-	breakpoint_remove(target, exit_point);
+	if (exit_point)
+		breakpoint_remove(target, exit_point);
 
 	if (retval != ERROR_OK)
 		return retval;
diff --git a/src/target/armv4_5.h b/src/target/armv4_5.h
index aed3a48d..3c8411f0 100644
--- a/src/target/armv4_5.h
+++ b/src/target/armv4_5.h
@@ -76,6 +76,7 @@ typedef struct armv4_5_common_s
 	reg_cache_t *core_cache;
 	enum armv4_5_mode core_mode;
 	enum armv4_5_state core_state;
+	bool is_armv4;
 	int (*full_context)(struct target_s *target);
 	int (*read_core_reg)(struct target_s *target, int num, enum armv4_5_mode mode);
 	int (*write_core_reg)(struct target_s *target, int num, enum armv4_5_mode mode, uint32_t value);