MIPS: update arch_info access to match other targets

 - add target_to_mips32 and target_to_m4k to match test of codebase.
 - mips32_arch_state now shows if processer is running mips16e isa.

Signed-off-by: Spencer Oliver <ntfreak@users.sourceforge.net>

7 files changed, 107 insertions, 68 deletions

diff --git a/src/target/mips32.c b/src/target/mips32.c
index 0f6f9b09..5bb4104e 100644
--- a/src/target/mips32.c
+++ b/src/target/mips32.c
@@ -38,6 +38,11 @@ char* mips32_core_reg_list[] =
 	"status", "lo", "hi", "badvaddr", "cause", "pc"
 };
 
+const char *mips_isa_strings[] =
+{
+	"MIPS32", "MIPS16e"
+};
+
 struct mips32_core_reg mips32_core_reg_list_arch_info[MIPS32NUMCOREREGS] =
 {
 	{0, NULL, NULL},
@@ -103,7 +108,7 @@ int mips32_get_core_reg(struct reg *reg)
 	int retval;
 	struct mips32_core_reg *mips32_reg = reg->arch_info;
 	struct target *target = mips32_reg->target;
-	struct mips32_common *mips32_target = target->arch_info;
+	struct mips32_common *mips32_target = target_to_mips32(target);
 
 	if (target->state != TARGET_HALTED)
 	{
@@ -139,7 +144,7 @@ int mips32_read_core_reg(struct target *target, int num)
 	struct mips32_core_reg *mips_core_reg;
 
 	/* get pointers to arch-specific information */
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 
 	if ((num < 0) || (num >= MIPS32NUMCOREREGS))
 		return ERROR_INVALID_ARGUMENTS;
@@ -159,7 +164,7 @@ int mips32_write_core_reg(struct target *target, int num)
 	struct mips32_core_reg *mips_core_reg;
 
 	/* get pointers to arch-specific information */
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 
 	if ((num < 0) || (num >= MIPS32NUMCOREREGS))
 		return ERROR_INVALID_ARGUMENTS;
@@ -177,7 +182,7 @@ int mips32_write_core_reg(struct target *target, int num)
 int mips32_get_gdb_reg_list(struct target *target, struct reg **reg_list[], int *reg_list_size)
 {
 	/* get pointers to arch-specific information */
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	int i;
 
 	/* include floating point registers */
@@ -203,7 +208,7 @@ int mips32_save_context(struct target *target)
 	int i;
 
 	/* get pointers to arch-specific information */
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
 
 	/* read core registers */
@@ -225,7 +230,7 @@ int mips32_restore_context(struct target *target)
 	int i;
 
 	/* get pointers to arch-specific information */
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
 
 	for (i = 0; i < MIPS32NUMCOREREGS; i++)
@@ -244,15 +249,10 @@ int mips32_restore_context(struct target *target)
 
 int mips32_arch_state(struct target *target)
 {
-	struct mips32_common *mips32 = target->arch_info;
-
-	if (mips32->common_magic != MIPS32_COMMON_MAGIC)
-	{
-		LOG_ERROR("BUG: called for a non-MIPS32 target");
-		return ERROR_FAIL;
-	}
+	struct mips32_common *mips32 = target_to_mips32(target);
 
-	LOG_USER("target halted due to %s, pc: 0x%8.8" PRIx32 "",
+	LOG_USER("target halted in %s mode due to %s, pc: 0x%8.8" PRIx32 "",
+		mips_isa_strings[mips32->isa_mode],
 		debug_reason_name(target),
 		buf_get_u32(mips32->core_cache->reg_list[MIPS32_PC].value, 0, 32));
 
@@ -267,7 +267,7 @@ static const struct reg_arch_type mips32_reg_type = {
 struct reg_cache *mips32_build_reg_cache(struct target *target)
 {
 	/* get pointers to arch-specific information */
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 
 	int num_regs = MIPS32NUMCOREREGS;
 	struct reg_cache **cache_p = register_get_last_cache_p(&target->reg_cache);
@@ -327,7 +327,7 @@ int mips32_run_algorithm(struct target *target, int num_mem_params, struct mem_p
 
 int mips32_examine(struct target *target)
 {
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 
 	if (!target_was_examined(target))
 	{
@@ -347,7 +347,7 @@ int mips32_examine(struct target *target)
 int mips32_configure_break_unit(struct target *target)
 {
 	/* get pointers to arch-specific information */
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	int retval;
 	uint32_t dcr, bpinfo;
 	int i;
@@ -359,7 +359,7 @@ int mips32_configure_break_unit(struct target *target)
 	if ((retval = target_read_u32(target, EJTAG_DCR, &dcr)) != ERROR_OK)
 		return retval;
 
-	if (dcr & (1 << 16))
+	if (dcr & EJTAG_DCR_IB)
 	{
 		/* get number of inst breakpoints */
 		if ((retval = target_read_u32(target, EJTAG_IBS, &bpinfo)) != ERROR_OK)
@@ -378,7 +378,7 @@ int mips32_configure_break_unit(struct target *target)
 			return retval;
 	}
 
-	if (dcr & (1 << 17))
+	if (dcr & EJTAG_DCR_DB)
 	{
 		/* get number of data breakpoints */
 		if ((retval = target_read_u32(target, EJTAG_DBS, &bpinfo)) != ERROR_OK)
@@ -416,19 +416,19 @@ int mips32_enable_interrupts(struct target *target, int enable)
 
 	if (enable)
 	{
-		if (!(dcr & (1 << 4)))
+		if (!(dcr & EJTAG_DCR_INTE))
 		{
 			/* enable interrupts */
-			dcr |= (1 << 4);
+			dcr |= EJTAG_DCR_INTE;
 			update = 1;
 		}
 	}
 	else
 	{
-		if (dcr & (1 << 4))
+		if (dcr & EJTAG_DCR_INTE)
 		{
 			/* disable interrupts */
-			dcr &= ~(1 << 4);
+			dcr &= ~EJTAG_DCR_INTE;
 			update = 1;
 		}
 	}
diff --git a/src/target/mips32.h b/src/target/mips32.h
index 4fe61bcd..b731c686 100644
--- a/src/target/mips32.h
+++ b/src/target/mips32.h
@@ -26,7 +26,6 @@
 #include "target.h"
 #include "mips32_pracc.h"
 
-
 #define MIPS32_COMMON_MAGIC		0xB320B320
 
 /* offsets into mips32 core register cache */
@@ -36,10 +35,17 @@ enum
 	MIPS32NUMCOREREGS
 };
 
+enum mips32_isa_mode
+{
+	MIPS32_ISA_MIPS32 = 0,
+	MIPS32_ISA_MIPS16E = 1,
+};
+
+extern const char *mips_isa_strings[];
+
 struct mips32_comparator
 {
 	int used;
-	//int type;
 	uint32_t bp_value;
 	uint32_t reg_address;
 };
@@ -51,6 +57,7 @@ struct mips32_common
 	struct reg_cache *core_cache;
 	struct mips_ejtag ejtag_info;
 	uint32_t core_regs[MIPS32NUMCOREREGS];
+	enum mips32_isa_mode isa_mode;
 
 	int bp_scanned;
 	int num_inst_bpoints;
@@ -65,6 +72,12 @@ struct mips32_common
 	int (*write_core_reg)(struct target *target, int num);
 };
 
+static inline struct mips32_common *
+target_to_mips32(struct target *target)
+{
+	return target->arch_info;
+}
+
 struct mips32_core_reg
 {
 	uint32_t num;
diff --git a/src/target/mips32_pracc.c b/src/target/mips32_pracc.c
index 52d31bdf..11d5a43a 100644
--- a/src/target/mips32_pracc.c
+++ b/src/target/mips32_pracc.c
@@ -810,7 +810,7 @@ int mips32_pracc_write_regs(struct mips_ejtag *ejtag_info, uint32_t *regs)
 		MIPS32_LW(2,36*4,1),							/* lw $2,36*4($1) */
 		MIPS32_MTC0(2,13,0),							/* move $2 to cause*/
 		MIPS32_LW(2,37*4,1),							/* lw $2,37*4($1) */
-		MIPS32_MTC0(2,24,0),							/* move $2 to pc */
+		MIPS32_MTC0(2,24,0),							/* move $2 to depc (pc) */
 
 		MIPS32_LW(2,2*4,1),								/* lw $2,2*4($1) */
 		MIPS32_LW(1,0,15),								/* lw $1,($15) */
@@ -884,7 +884,7 @@ int mips32_pracc_read_regs(struct mips_ejtag *ejtag_info, uint32_t *regs)
 		MIPS32_SW(2,35*4,1),							/* sw $2,35*4($1) */
 		MIPS32_MFC0(2,13,0),							/* move cause to $2 */
 		MIPS32_SW(2,36*4,1),							/* sw $2,36*4($1) */
-		MIPS32_MFC0(2,24,0),							/* move pc to $2 */
+		MIPS32_MFC0(2,24,0),							/* move depc (pc) to $2 */
 		MIPS32_SW(2,37*4,1),							/* sw $2,37*4($1) */
 
 		MIPS32_LW(2,0,15),								/* lw $2,($15) */
diff --git a/src/target/mips_ejtag.c b/src/target/mips_ejtag.c
index 58bd392b..336adb50 100644
--- a/src/target/mips_ejtag.c
+++ b/src/target/mips_ejtag.c
@@ -264,16 +264,15 @@ int mips_ejtag_init(struct mips_ejtag *ejtag_info)
 			break;
 	}
 	LOG_DEBUG("EJTAG: features:%s%s%s%s%s%s%s",
-		ejtag_info->impcode & (1 << 28) ? " R3k":    " R4k",
-		ejtag_info->impcode & (1 << 24) ? " DINT":   "",
-		ejtag_info->impcode & (1 << 22) ? " ASID_8": "",
-		ejtag_info->impcode & (1 << 21) ? " ASID_6": "",
-		ejtag_info->impcode & (1 << 16) ? " MIPS16": "",
-		ejtag_info->impcode & (1 << 14) ? " noDMA":  " DMA",
-		ejtag_info->impcode & (1 << 0)  ? " MIPS64": " MIPS32"
-);
-
-	if ((ejtag_info->impcode & (1 << 14)) == 0)
+		ejtag_info->impcode & EJTAG_IMP_R3K ? " R3k" : " R4k",
+		ejtag_info->impcode & EJTAG_IMP_DINT ? " DINT" : "",
+		ejtag_info->impcode & (1 << 22) ? " ASID_8" : "",
+		ejtag_info->impcode & (1 << 21) ? " ASID_6" : "",
+		ejtag_info->impcode & EJTAG_IMP_MIPS16 ? " MIPS16" : "",
+		ejtag_info->impcode & EJTAG_IMP_NODMA ? " noDMA" : " DMA",
+		ejtag_info->impcode & EJTAG_DCR_MIPS64  ? " MIPS64" : " MIPS32");
+
+	if ((ejtag_info->impcode & EJTAG_IMP_NODMA) == 0)
 		LOG_DEBUG("EJTAG: DMA Access Mode Support Enabled");
 
 	/* set initial state for ejtag control reg */
diff --git a/src/target/mips_ejtag.h b/src/target/mips_ejtag.h
index e9da39ec..2f62f2be 100644
--- a/src/target/mips_ejtag.h
+++ b/src/target/mips_ejtag.h
@@ -40,7 +40,7 @@
 #define EJTAG_INST_TCBDATA		0x12
 #define EJTAG_INST_BYPASS		0xFF
 
-/* debug control register bits ECR */
+/* ejtag control register bits ECR */
 #define EJTAG_CTRL_TOF			(1 << 1)
 #define EJTAG_CTRL_TIF			(1 << 2)
 #define EJTAG_CTRL_BRKST		(1 << 3)
@@ -87,11 +87,20 @@
 #define EJTAG_DEBUG_DBD			(1 << 31)
 
 /* implementaion register bits */
+#define EJTAG_IMP_R3K			(1 << 28)
+#define EJTAG_IMP_DINT			(1 << 24)
 #define EJTAG_IMP_NODMA			(1 << 14)
 #define EJTAG_IMP_MIPS16		(1 << 16)
+#define EJTAG_DCR_MIPS64		(1 << 0)
 
-/* breakpoint support */
+/* Debug Control Register DCR */
 #define EJTAG_DCR				0xFF300000
+#define EJTAG_DCR_ENM			(1 << 29)
+#define EJTAG_DCR_DB			(1 << 17)
+#define EJTAG_DCR_IB			(1 << 16)
+#define EJTAG_DCR_INTE			(1 << 4)
+
+/* breakpoint support */
 #define EJTAG_IBS				0xFF301000
 #define EJTAG_IBA1				0xFF301100
 #define EJTAG_DBS				0xFF302000
@@ -107,7 +116,6 @@ struct mips_ejtag
 	struct jtag_tap *tap;
 	uint32_t impcode;
 	uint32_t idcode;
-	/*int use_dma;*/
 	uint32_t ejtag_ctrl;
 };
 
diff --git a/src/target/mips_m4k.c b/src/target/mips_m4k.c
index f229690b..1a65c50b 100644
--- a/src/target/mips_m4k.c
+++ b/src/target/mips_m4k.c
@@ -107,12 +107,12 @@ int mips_m4k_examine_debug_reason(struct target *target)
 		}
 
 		/* get info about data breakpoint support */
-		if ((retval = target_read_u32(target, 0xFF302000, &break_status)) != ERROR_OK)
+		if ((retval = target_read_u32(target, EJTAG_DBS, &break_status)) != ERROR_OK)
 			return retval;
 		if (break_status & 0x1f)
 		{
 			/* we have halted on a  breakpoint */
-			if ((retval = target_write_u32(target, 0xFF302000, 0)) != ERROR_OK)
+			if ((retval = target_write_u32(target, EJTAG_DBS, 0)) != ERROR_OK)
 				return retval;
 			target->debug_reason = DBG_REASON_WATCHPOINT;
 		}
@@ -123,14 +123,14 @@ int mips_m4k_examine_debug_reason(struct target *target)
 
 int mips_m4k_debug_entry(struct target *target)
 {
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
 	uint32_t debug_reg;
 
 	/* read debug register */
 	mips_ejtag_read_debug(ejtag_info, &debug_reg);
 
-	/* make sure break uit configured */
+	/* make sure break unit configured */
 	mips32_configure_break_unit(target);
 
 	/* attempt to find halt reason */
@@ -145,9 +145,21 @@ int mips_m4k_debug_entry(struct target *target)
 
 	mips32_save_context(target);
 
+	/* default to mips32 isa, it will be changed below if required */
+	mips32->isa_mode = MIPS32_ISA_MIPS32;
+
+	if (ejtag_info->impcode & EJTAG_IMP_MIPS16)
+	{
+		if (buf_get_u32(mips32->core_cache->reg_list[MIPS32_PC].value, 0, 32) & 0x01)
+		{
+			/* core is running mips16e isa */
+			mips32->isa_mode = MIPS32_ISA_MIPS16E;
+		}
+	}
+
 	LOG_DEBUG("entered debug state at PC 0x%" PRIx32 ", target->state: %s",
-		*(uint32_t*)(mips32->core_cache->reg_list[MIPS32_PC].value),
-		  target_state_name(target));
+			buf_get_u32(mips32->core_cache->reg_list[MIPS32_PC].value, 0, 32),
+			target_state_name(target));
 
 	return ERROR_OK;
 }
@@ -155,7 +167,7 @@ int mips_m4k_debug_entry(struct target *target)
 int mips_m4k_poll(struct target *target)
 {
 	int retval;
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
 	uint32_t ejtag_ctrl = ejtag_info->ejtag_ctrl;
 
@@ -215,7 +227,7 @@ int mips_m4k_poll(struct target *target)
 
 int mips_m4k_halt(struct target *target)
 {
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
 
 	LOG_DEBUG("target->state: %s",
@@ -260,7 +272,7 @@ int mips_m4k_halt(struct target *target)
 
 int mips_m4k_assert_reset(struct target *target)
 {
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
 
 	LOG_DEBUG("target->state: %s",
@@ -339,7 +351,7 @@ int mips_m4k_soft_reset_halt(struct target *target)
 
 int mips_m4k_single_step_core(struct target *target)
 {
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
 
 	/* configure single step mode */
@@ -358,7 +370,7 @@ int mips_m4k_single_step_core(struct target *target)
 
 int mips_m4k_resume(struct target *target, int current, uint32_t address, int handle_breakpoints, int debug_execution)
 {
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
 	struct breakpoint *breakpoint = NULL;
 	uint32_t resume_pc;
@@ -430,7 +442,7 @@ int mips_m4k_resume(struct target *target, int current, uint32_t address, int ha
 int mips_m4k_step(struct target *target, int current, uint32_t address, int handle_breakpoints)
 {
 	/* get pointers to arch-specific information */
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
 	struct breakpoint *breakpoint = NULL;
 
@@ -494,7 +506,7 @@ void mips_m4k_enable_breakpoints(struct target *target)
 
 int mips_m4k_set_breakpoint(struct target *target, struct breakpoint *breakpoint)
 {
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips32_comparator * comparator_list = mips32->inst_break_list;
 	int retval;
 
@@ -585,8 +597,8 @@ int mips_m4k_set_breakpoint(struct target *target, struct breakpoint *breakpoint
 int mips_m4k_unset_breakpoint(struct target *target, struct breakpoint *breakpoint)
 {
 	/* get pointers to arch-specific information */
-	struct mips32_common *mips32 = target->arch_info;
-	struct mips32_comparator * comparator_list = mips32->inst_break_list;
+	struct mips32_common *mips32 = target_to_mips32(target);
+	struct mips32_comparator *comparator_list = mips32->inst_break_list;
 	int retval;
 
 	if (!breakpoint->set)
@@ -659,7 +671,7 @@ int mips_m4k_unset_breakpoint(struct target *target, struct breakpoint *breakpoi
 
 int mips_m4k_add_breakpoint(struct target *target, struct breakpoint *breakpoint)
 {
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 
 	if (breakpoint->type == BKPT_HARD)
 	{
@@ -680,7 +692,7 @@ int mips_m4k_add_breakpoint(struct target *target, struct breakpoint *breakpoint
 int mips_m4k_remove_breakpoint(struct target *target, struct breakpoint *breakpoint)
 {
 	/* get pointers to arch-specific information */
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 
 	if (target->state != TARGET_HALTED)
 	{
@@ -701,8 +713,8 @@ int mips_m4k_remove_breakpoint(struct target *target, struct breakpoint *breakpo
 
 int mips_m4k_set_watchpoint(struct target *target, struct watchpoint *watchpoint)
 {
-	struct mips32_common *mips32 = target->arch_info;
-	struct mips32_comparator * comparator_list = mips32->data_break_list;
+	struct mips32_common *mips32 = target_to_mips32(target);
+	struct mips32_comparator *comparator_list = mips32->data_break_list;
 	int wp_num = 0;
 	/*
 	 * watchpoint enabled, ignore all byte lanes in value register
@@ -769,8 +781,8 @@ int mips_m4k_set_watchpoint(struct target *target, struct watchpoint *watchpoint
 int mips_m4k_unset_watchpoint(struct target *target, struct watchpoint *watchpoint)
 {
 	/* get pointers to arch-specific information */
-	struct mips32_common *mips32 = target->arch_info;
-	struct mips32_comparator * comparator_list = mips32->data_break_list;
+	struct mips32_common *mips32 = target_to_mips32(target);
+	struct mips32_comparator *comparator_list = mips32->data_break_list;
 
 	if (!watchpoint->set)
 	{
@@ -794,7 +806,7 @@ int mips_m4k_unset_watchpoint(struct target *target, struct watchpoint *watchpoi
 
 int mips_m4k_add_watchpoint(struct target *target, struct watchpoint *watchpoint)
 {
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 
 	if (mips32->num_data_bpoints_avail < 1)
 	{
@@ -811,7 +823,7 @@ int mips_m4k_add_watchpoint(struct target *target, struct watchpoint *watchpoint
 int mips_m4k_remove_watchpoint(struct target *target, struct watchpoint *watchpoint)
 {
 	/* get pointers to arch-specific information */
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 
 	if (target->state != TARGET_HALTED)
 	{
@@ -844,7 +856,7 @@ void mips_m4k_enable_watchpoints(struct target *target)
 
 int mips_m4k_read_memory(struct target *target, uint32_t address, uint32_t size, uint32_t count, uint8_t *buffer)
 {
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
 
 	LOG_DEBUG("address: 0x%8.8" PRIx32 ", size: 0x%8.8" PRIx32 ", count: 0x%8.8" PRIx32 "", address, size, count);
@@ -876,7 +888,7 @@ int mips_m4k_read_memory(struct target *target, uint32_t address, uint32_t size,
 
 int mips_m4k_write_memory(struct target *target, uint32_t address, uint32_t size, uint32_t count, uint8_t *buffer)
 {
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
 
 	LOG_DEBUG("address: 0x%8.8" PRIx32 ", size: 0x%8.8" PRIx32 ", count: 0x%8.8" PRIx32 "", address, size, count);
@@ -923,7 +935,7 @@ int mips_m4k_init_arch_info(struct target *target, struct mips_m4k_common *mips_
 
 int mips_m4k_target_create(struct target *target, Jim_Interp *interp)
 {
-	struct mips_m4k_common *mips_m4k = calloc(1,sizeof(struct mips_m4k_common));
+	struct mips_m4k_common *mips_m4k = calloc(1, sizeof(struct mips_m4k_common));
 
 	mips_m4k_init_arch_info(target, mips_m4k, target->tap);
 
@@ -933,7 +945,7 @@ int mips_m4k_target_create(struct target *target, Jim_Interp *interp)
 int mips_m4k_examine(struct target *target)
 {
 	int retval;
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
 	uint32_t idcode = 0;
 
@@ -963,7 +975,7 @@ int mips_m4k_examine(struct target *target)
 
 int mips_m4k_bulk_write_memory(struct target *target, uint32_t address, uint32_t count, uint8_t *buffer)
 {
-	struct mips32_common *mips32 = target->arch_info;
+	struct mips32_common *mips32 = target_to_mips32(target);
 	struct mips_ejtag *ejtag_info = &mips32->ejtag_info;
 	struct working_area *source;
 	int retval;
diff --git a/src/target/mips_m4k.h b/src/target/mips_m4k.h
index c5f9be2b..4fe14a0d 100644
--- a/src/target/mips_m4k.h
+++ b/src/target/mips_m4k.h
@@ -35,6 +35,13 @@ struct mips_m4k_common
 	struct mips32_common mips32_common;
 };
 
+static inline struct mips_m4k_common *
+target_to_m4k(struct target *target)
+{
+	return container_of(target->arch_info,
+			struct mips_m4k_common, mips32_common);
+}
+
 int mips_m4k_bulk_write_memory(struct target *target,
 		uint32_t address, uint32_t count, uint8_t *buffer);