John McCarthy <jgmcc@magma.ca> adds support for DMA mode access as supported by EJTAG 1.0/2.0 processors

git-svn-id: svn://svn.berlios.de/openocd/trunk@1029 b42882b7-edfa-0310-969c-e2dbd0fdcd60

6 files changed, 521 insertions, 5 deletions

diff --git a/src/target/Makefile.am b/src/target/Makefile.am
index b29b4005..6a7c3c7e 100644
--- a/src/target/Makefile.am
+++ b/src/target/Makefile.am
@@ -13,11 +13,11 @@ libtarget_a_SOURCES = target.c register.c breakpoints.c armv4_5.c embeddedice.c
 	arm_jtag.c arm7_9_common.c algorithm.c arm920t.c arm720t.c armv4_5_mmu.c armv4_5_cache.c arm_disassembler.c \
 	arm966e.c arm926ejs.c feroceon.c etb.c xscale.c arm_simulator.c image.c armv7m.c cortex_m3.c cortex_swjdp.c \
 	etm_dummy.c $(OOCD_TRACE_FILES) target_request.c trace.c arm11.c arm11_dbgtap.c mips32.c mips_m4k.c \
-	mips32_pracc.c mips_ejtag.c
+	mips32_pracc.c mips32_dmaacc.c mips_ejtag.c
 noinst_HEADERS = target.h trace.h register.h armv4_5.h embeddedice.h etm.h arm7tdmi.h arm9tdmi.h \
 	arm_jtag.h arm7_9_common.h arm920t.h arm720t.h armv4_5_mmu.h armv4_5_cache.h breakpoints.h algorithm.h \
 	arm_disassembler.h arm966e.h arm926ejs.h etb.h xscale.h arm_simulator.h image.h armv7m.h cortex_m3.h cortex_swjdp.h \
-	etm_dummy.h oocd_trace.h target_request.h trace.h arm11.h mips32.h mips_m4k.h mips_ejtag.h mips32_pracc.h
+	etm_dummy.h oocd_trace.h target_request.h trace.h arm11.h mips32.h mips_m4k.h mips_ejtag.h mips32_pracc.h mips32_dmaacc.h
 
 nobase_dist_pkglib_DATA = xscale/debug_handler.bin target/at91eb40a.cfg \
 	event/at91r40008_reset.script event/sam7x256_reset.script \
diff --git a/src/target/mips32_dmaacc.c b/src/target/mips32_dmaacc.c
new file mode 100644
index 00000000..96426c0a
--- /dev/null
+++ b/src/target/mips32_dmaacc.c
@@ -0,0 +1,441 @@
+/***************************************************************************

+ *   Copyright (C) 2008 by John McCarthy                                   *

+ *   jgmcc@magma.ca                                                        *

+ *                                                                         *

+ *   Copyright (C) 2008 by Spencer Oliver                                  *

+ *   spen@spen-soft.co.uk                                                  *

+ *                                                                         *

+ *   Copyright (C) 2008 by David T.L. Wong                                 *

+ *                                                                         *

+ *   This program is free software; you can redistribute it and/or modify  *

+ *   it under the terms of the GNU General Public License as published by  *

+ *   the Free Software Foundation; either version 2 of the License, or     *

+ *   (at your option) any later version.                                   *

+ *                                                                         *

+ *   This program is distributed in the hope that it will be useful,       *

+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *

+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *

+ *   GNU General Public License for more details.                          *

+ *                                                                         *

+ *   You should have received a copy of the GNU General Public License     *

+ *   along with this program; if not, write to the                         *

+ *   Free Software Foundation, Inc.,                                       *

+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *

+ ***************************************************************************/

+#ifdef HAVE_CONFIG_H

+#include "config.h"

+#endif

+

+#include <string.h>

+#include "log.h"

+#include "mips32.h"

+#include "mips32_dmaacc.h"

+

+/*

+ * The following logic shamelessly cloned from HairyDairyMaid's wrt54g_debrick

+ * to support the Broadcom BCM5352 SoC in the Linksys WRT54GL wireless router

+ * (and any others that support EJTAG DMA transfers).

+ * Note: This only supports memory read/write. Since the BCM5352 doesn't

+ * appear to support PRACC accesses, all debug functions except halt

+ * do not work.  Still, this does allow erasing/writing flash as well as

+ * displaying/modifying memory and memory mapped registers.

+ */

+

+static int ejtag_dma_read(mips_ejtag_t *ejtag_info, u32 addr, u32 *data)

+{

+	u32 v;

+	u32 ctrl_reg;

+	int   retries = RETRY_ATTEMPTS;

+

+begin_ejtag_dma_read:

+

+	// Setup Address

+	v = addr;

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ADDRESS, NULL);

+	mips_ejtag_drscan_32(ejtag_info, &v);

+

+	// Initiate DMA Read & set DSTRT

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL, NULL);

+	ctrl_reg = EJTAG_CTRL_DMAACC | EJTAG_CTRL_DRWN | EJTAG_CTRL_DMA_WORD | EJTAG_CTRL_DSTRT | EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+	mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+

+	// Wait for DSTRT to Clear

+	do {

+		ctrl_reg = EJTAG_CTRL_DMAACC | EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+		mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+	} while(ctrl_reg & EJTAG_CTRL_DSTRT);

+

+	// Read Data

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_DATA, NULL);

+	mips_ejtag_drscan_32(ejtag_info, data);

+

+	// Clear DMA & Check DERR

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL, NULL);

+	ctrl_reg = EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+	mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+	if (ctrl_reg  & EJTAG_CTRL_DERR)

+	{

+		if (retries--) {

+			printf("DMA Read Addr = %08x  Data = ERROR ON READ (retrying)\n", addr);

+			goto begin_ejtag_dma_read;

+		} else	printf("DMA Read Addr = %08x  Data = ERROR ON READ\n", addr);

+		return ERROR_JTAG_DEVICE_ERROR;

+	}

+

+	return ERROR_OK;

+}

+

+static int ejtag_dma_read_h(mips_ejtag_t *ejtag_info, u32 addr, u16 *data)

+{

+	u32 v;

+	u32 ctrl_reg;

+	int   retries = RETRY_ATTEMPTS;

+

+begin_ejtag_dma_read_h:

+

+	// Setup Address

+	v = addr;

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ADDRESS, NULL);

+	mips_ejtag_drscan_32(ejtag_info, &v);

+

+	// Initiate DMA Read & set DSTRT

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL, NULL);

+	ctrl_reg = EJTAG_CTRL_DMAACC | EJTAG_CTRL_DRWN | EJTAG_CTRL_DMA_HALFWORD | EJTAG_CTRL_DSTRT | EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+	mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+

+	// Wait for DSTRT to Clear

+	do {

+		ctrl_reg = EJTAG_CTRL_DMAACC | EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+		mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+	} while(ctrl_reg & EJTAG_CTRL_DSTRT);

+

+	// Read Data

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_DATA, NULL);

+	mips_ejtag_drscan_32(ejtag_info, &v);

+

+	// Clear DMA & Check DERR

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL, NULL);

+	ctrl_reg = EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+	mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+	if (ctrl_reg  & EJTAG_CTRL_DERR)

+	{

+		if (retries--) {

+			printf("DMA Read Addr = %08x  Data = ERROR ON READ (retrying)\n", addr);

+			goto begin_ejtag_dma_read_h;

+		} else	printf("DMA Read Addr = %08x  Data = ERROR ON READ\n", addr);

+		return ERROR_JTAG_DEVICE_ERROR;

+	}

+

+	// Handle the bigendian/littleendian

+	if ( addr & 0x2 )  *data = (v>>16)&0xffff ;

+	else               *data = (v&0x0000ffff) ;

+

+	return ERROR_OK;

+}

+

+static int ejtag_dma_read_b(mips_ejtag_t *ejtag_info, u32 addr, u8 *data)

+{

+	u32 v;

+	u32 ctrl_reg;

+	int   retries = RETRY_ATTEMPTS;

+

+begin_ejtag_dma_read_b:

+

+	// Setup Address

+	v = addr;

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ADDRESS, NULL);

+	mips_ejtag_drscan_32(ejtag_info, &v);

+

+	// Initiate DMA Read & set DSTRT

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL, NULL);

+	ctrl_reg = EJTAG_CTRL_DMAACC | EJTAG_CTRL_DRWN | EJTAG_CTRL_DMA_BYTE | EJTAG_CTRL_DSTRT | EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+	mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+

+	// Wait for DSTRT to Clear

+	do {

+		ctrl_reg = EJTAG_CTRL_DMAACC | EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+		mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+	} while(ctrl_reg & EJTAG_CTRL_DSTRT);

+

+	// Read Data

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_DATA, NULL);

+	mips_ejtag_drscan_32(ejtag_info, &v);

+

+	// Clear DMA & Check DERR

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL, NULL);

+	ctrl_reg = EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+	mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+	if (ctrl_reg  & EJTAG_CTRL_DERR)

+	{

+		if (retries--) {

+			printf("DMA Read Addr = %08x  Data = ERROR ON READ (retrying)\n", addr);

+			goto begin_ejtag_dma_read_b;

+		} else	printf("DMA Read Addr = %08x  Data = ERROR ON READ\n", addr);

+		return ERROR_JTAG_DEVICE_ERROR;

+	}

+

+	// Handle the bigendian/littleendian

+	switch(addr & 0x3) {

+	case 0:  *data =  v      & 0xff; break;

+	case 1:  *data = (v>>8)  & 0xff; break;

+	case 2:  *data = (v>>16) & 0xff; break;

+	case 3:  *data = (v>>24) & 0xff; break;

+	}

+

+	return ERROR_OK;

+}

+

+static int ejtag_dma_write(mips_ejtag_t *ejtag_info, u32 addr, u32 data)

+{

+	u32 v;

+	u32 ctrl_reg;

+	int   retries = RETRY_ATTEMPTS;

+

+begin_ejtag_dma_write:

+

+	// Setup Address

+	v = addr;

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ADDRESS, NULL);

+	mips_ejtag_drscan_32(ejtag_info, &v);

+

+	// Setup Data

+	v = data;

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_DATA, NULL);

+	mips_ejtag_drscan_32(ejtag_info, &v);

+

+	// Initiate DMA Write & set DSTRT

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL, NULL);

+	ctrl_reg = EJTAG_CTRL_DMAACC | EJTAG_CTRL_DMA_WORD | EJTAG_CTRL_DSTRT | EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+	mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+

+	// Wait for DSTRT to Clear

+	do {

+		ctrl_reg = EJTAG_CTRL_DMAACC | EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+		mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+	} while(ctrl_reg & EJTAG_CTRL_DSTRT);

+

+	// Clear DMA & Check DERR

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL, NULL);

+	ctrl_reg = EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+	mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+	if (ctrl_reg  & EJTAG_CTRL_DERR)

+	{

+		if (retries--) {

+			printf("DMA Write Addr = %08x  Data = ERROR ON WRITE (retrying)\n", addr);

+			goto begin_ejtag_dma_write;

+		} else	printf("DMA Write Addr = %08x  Data = ERROR ON WRITE\n", addr);

+		return ERROR_JTAG_DEVICE_ERROR;

+	}

+

+	return ERROR_OK;

+}

+

+static int ejtag_dma_write_h(mips_ejtag_t *ejtag_info, u32 addr, u32 data)

+{

+	u32 v;

+	u32 ctrl_reg;

+	int   retries = RETRY_ATTEMPTS;

+

+

+	// Handle the bigendian/littleendian

+	data &= 0xffff;

+	data |= data<<16;

+

+begin_ejtag_dma_write_h:

+

+	// Setup Address

+	v = addr;

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ADDRESS, NULL);

+	mips_ejtag_drscan_32(ejtag_info, &v);

+

+	// Setup Data

+	v = data;

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_DATA, NULL);

+	mips_ejtag_drscan_32(ejtag_info, &v);

+

+	// Initiate DMA Write & set DSTRT

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL, NULL);

+	ctrl_reg = EJTAG_CTRL_DMAACC | EJTAG_CTRL_DMA_HALFWORD | EJTAG_CTRL_DSTRT | EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+	mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+

+	// Wait for DSTRT to Clear

+	do {

+		ctrl_reg = EJTAG_CTRL_DMAACC | EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+		mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+	} while(ctrl_reg & EJTAG_CTRL_DSTRT);

+

+	// Clear DMA & Check DERR

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL, NULL);

+	ctrl_reg = EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+	mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+	if (ctrl_reg  & EJTAG_CTRL_DERR)

+	{

+		if (retries--) {

+			printf("DMA Write Addr = %08x  Data = ERROR ON WRITE (retrying)\n", addr);

+			goto begin_ejtag_dma_write_h;

+		} else	printf("DMA Write Addr = %08x  Data = ERROR ON WRITE\n", addr);

+		return ERROR_JTAG_DEVICE_ERROR;

+	}

+

+	return ERROR_OK;

+}

+

+static int ejtag_dma_write_b(mips_ejtag_t *ejtag_info, u32 addr, u32 data)

+{

+	u32 v;

+	u32 ctrl_reg;

+	int   retries = RETRY_ATTEMPTS;

+

+

+	// Handle the bigendian/littleendian

+	data &= 0xff;

+	data |= data<<8;

+	data |= data<<16;

+

+begin_ejtag_dma_write_b:

+

+	// Setup Address

+	v = addr;

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ADDRESS, NULL);

+	mips_ejtag_drscan_32(ejtag_info, &v);

+

+	// Setup Data

+	v = data;

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_DATA, NULL);

+	mips_ejtag_drscan_32(ejtag_info, &v);

+

+	// Initiate DMA Write & set DSTRT

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL, NULL);

+	ctrl_reg = EJTAG_CTRL_DMAACC | EJTAG_CTRL_DMA_BYTE | EJTAG_CTRL_DSTRT | EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+	mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+

+	// Wait for DSTRT to Clear

+	do {

+		ctrl_reg = EJTAG_CTRL_DMAACC | EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+		mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+	} while(ctrl_reg & EJTAG_CTRL_DSTRT);

+

+	// Clear DMA & Check DERR

+	mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL, NULL);

+	ctrl_reg = EJTAG_CTRL_PROBEN | EJTAG_CTRL_PRACC;

+	mips_ejtag_drscan_32(ejtag_info, &ctrl_reg);

+	if (ctrl_reg  & EJTAG_CTRL_DERR)

+	{

+		if (retries--) {

+			printf("DMA Write Addr = %08x  Data = ERROR ON WRITE (retrying)\n", addr);

+			goto begin_ejtag_dma_write_b;

+		} else	printf("DMA Write Addr = %08x  Data = ERROR ON WRITE\n", addr);

+		return ERROR_JTAG_DEVICE_ERROR;

+	}

+

+	return ERROR_OK;

+}

+

+

+int mips32_dmaacc_read_mem(mips_ejtag_t *ejtag_info, u32 addr, int size, int count, void *buf)

+{

+	switch (size)

+	{

+		case 1:

+			return mips32_dmaacc_read_mem8(ejtag_info, addr, count, (u8*)buf);

+		case 2:

+			return mips32_dmaacc_read_mem16(ejtag_info, addr, count, (u16*)buf);

+		case 4:

+			return mips32_dmaacc_read_mem32(ejtag_info, addr, count, (u32*)buf);

+	}

+

+	return ERROR_OK;

+}

+

+int mips32_dmaacc_read_mem32(mips_ejtag_t *ejtag_info, u32 addr, int count, u32 *buf)

+{

+	int i;

+	int	retval;

+

+	for(i=0; i<count; i++) {

+		if((retval=ejtag_dma_read(ejtag_info, addr+i*sizeof(*buf), &buf[i])) != ERROR_OK)

+			return retval;

+	}

+

+	return ERROR_OK;

+}

+

+int mips32_dmaacc_read_mem16(mips_ejtag_t *ejtag_info, u32 addr, int count, u16 *buf)

+{

+	int i;

+	int retval;

+

+	for(i=0; i<count; i++) {

+		if((retval=ejtag_dma_read_h(ejtag_info, addr+i*sizeof(*buf), &buf[i])) != ERROR_OK)

+			return retval;

+	}

+

+	return ERROR_OK;

+}

+

+int mips32_dmaacc_read_mem8(mips_ejtag_t *ejtag_info, u32 addr, int count, u8 *buf)

+{

+	int i;

+	int retval;

+

+	for(i=0; i<count; i++) {

+		if((retval=ejtag_dma_read_b(ejtag_info, addr+i*sizeof(*buf), &buf[i])) != ERROR_OK)

+			return retval;

+	}

+

+	return ERROR_OK;

+}

+

+int mips32_dmaacc_write_mem(mips_ejtag_t *ejtag_info, u32 addr, int size, int count, void *buf)

+{

+	switch (size)

+	{

+		case 1:

+			return mips32_dmaacc_write_mem8(ejtag_info, addr, count, (u8*)buf);

+		case 2:

+			return mips32_dmaacc_write_mem16(ejtag_info, addr, count,(u16*)buf);

+		case 4:

+			return mips32_dmaacc_write_mem32(ejtag_info, addr, count, (u32*)buf);

+	}

+

+	return ERROR_OK;

+}

+

+int mips32_dmaacc_write_mem32(mips_ejtag_t *ejtag_info, u32 addr, int count, u32 *buf)

+{

+	int i;

+	int retval;

+

+	for(i=0; i<count; i++) {

+		if((retval=ejtag_dma_write(ejtag_info, addr+i*sizeof(*buf), buf[i])) != ERROR_OK)

+			return retval;

+	}

+

+	return ERROR_OK;

+}

+

+int mips32_dmaacc_write_mem16(mips_ejtag_t *ejtag_info, u32 addr, int count, u16 *buf)

+{

+	int i;

+	int retval;

+

+	for(i=0; i<count; i++) {

+		if((retval=ejtag_dma_write_h(ejtag_info, addr+i*sizeof(*buf), buf[i])) != ERROR_OK)

+			return retval;

+	}

+

+	return ERROR_OK;

+}

+

+int mips32_dmaacc_write_mem8(mips_ejtag_t *ejtag_info, u32 addr, int count, u8 *buf)

+{

+	int i;

+	int retval;

+

+	for(i=0; i<count; i++) {

+		if((retval=ejtag_dma_write_b(ejtag_info, addr+i*sizeof(*buf), buf[i])) != ERROR_OK)

+			return retval;

+	}

+

+	return ERROR_OK;

+}

diff --git a/src/target/mips32_dmaacc.h b/src/target/mips32_dmaacc.h
new file mode 100644
index 00000000..b6d544c5
--- /dev/null
+++ b/src/target/mips32_dmaacc.h
@@ -0,0 +1,53 @@
+/***************************************************************************

+ *   Copyright (C) 2008 by John McCarthy                                   *

+ *   jgmcc@magma.ca                                                        *

+ *                                                                         *

+ *   Copyright (C) 2008 by Spencer Oliver                                  *

+ *   spen@spen-soft.co.uk                                                  *

+ *                                                                         *

+ *   Copyright (C) 2008 by David T.L. Wong                                 *

+ *                                                                         *

+ *   This program is free software; you can redistribute it and/or modify  *

+ *   it under the terms of the GNU General Public License as published by  *

+ *   the Free Software Foundation; either version 2 of the License, or     *

+ *   (at your option) any later version.                                   *

+ *                                                                         *

+ *   This program is distributed in the hope that it will be useful,       *

+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *

+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *

+ *   GNU General Public License for more details.                          *

+ *                                                                         *

+ *   You should have received a copy of the GNU General Public License     *

+ *   along with this program; if not, write to the                         *

+ *   Free Software Foundation, Inc.,                                       *

+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *

+ ***************************************************************************/

+#ifndef MIPS32_DMAACC_H

+#define MIPS32_DMAACC_H

+

+#include "mips_ejtag.h"

+

+#define EJTAG_CTRL_DMA_BYTE        0x00000000

+#define EJTAG_CTRL_DMA_HALFWORD    0x00000080

+#define EJTAG_CTRL_DMA_WORD        0x00000100

+#define EJTAG_CTRL_DMA_TRIPLEBYTE  0x00000180

+

+#define RETRY_ATTEMPTS	4

+

+extern int mips32_dmaacc_read_mem(mips_ejtag_t *ejtag_info, u32 addr, int size, int count, void *buf);

+extern int mips32_dmaacc_write_mem(mips_ejtag_t *ejtag_info, u32 addr, int size, int count, void *buf);

+

+extern int mips32_dmaacc_read_mem8(mips_ejtag_t *ejtag_info, u32 addr, int count, u8 *buf);

+extern int mips32_dmaacc_read_mem16(mips_ejtag_t *ejtag_info, u32 addr, int count, u16 *buf);

+extern int mips32_dmaacc_read_mem32(mips_ejtag_t *ejtag_info, u32 addr, int count, u32 *buf);

+

+extern int mips32_dmaacc_write_mem8(mips_ejtag_t *ejtag_info, u32 addr, int count, u8 *buf);

+extern int mips32_dmaacc_write_mem16(mips_ejtag_t *ejtag_info, u32 addr, int count, u16 *buf);

+extern int mips32_dmaacc_write_mem32(mips_ejtag_t *ejtag_info, u32 addr, int count, u32 *buf);

+

+#if 0

+extern int mips32_dmaacc_read_regs(mips_ejtag_t *ejtag_info, u32 *regs);

+extern int mips32_dmaacc_write_regs(mips_ejtag_t *ejtag_info, u32 *regs);

+#endif

+

+#endif

diff --git a/src/target/mips_ejtag.c b/src/target/mips_ejtag.c
index d2203685..6e6bd934 100644
--- a/src/target/mips_ejtag.c
+++ b/src/target/mips_ejtag.c
@@ -204,6 +204,9 @@ int mips_ejtag_enter_debug(mips_ejtag_t *ejtag_info)
 	/* break bit will be cleared by hardware */
 	ejtag_info->ejtag_ctrl = EJTAG_CTRL_ROCC | EJTAG_CTRL_PRACC | EJTAG_CTRL_PROBEN | EJTAG_CTRL_SETDEV;
 	mips_ejtag_drscan_32(ejtag_info, &ejtag_info->ejtag_ctrl);
+	LOG_DEBUG("ejtag_ctrl: 0x%8.8x", ejtag_info->ejtag_ctrl);
+	if((ejtag_info->ejtag_ctrl & EJTAG_CTRL_BRKST) == 0)
+		LOG_DEBUG("Failed to enter Debug Mode!");
 	
 	return ERROR_OK;
 }
@@ -275,6 +278,17 @@ int mips_ejtag_init(mips_ejtag_t *ejtag_info)
 			LOG_DEBUG("EJTAG: Unknown Version Detected");
 			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)
+		LOG_DEBUG("EJTAG: DMA Access Mode Support Enabled");
 	
 	/* set initial state for ejtag control reg */
 	ejtag_info->ejtag_ctrl = EJTAG_CTRL_ROCC | EJTAG_CTRL_PRACC | EJTAG_CTRL_PROBEN | EJTAG_CTRL_SETDEV;
diff --git a/src/target/mips_ejtag.h b/src/target/mips_ejtag.h
index b25bd026..cd31d233 100644
--- a/src/target/mips_ejtag.h
+++ b/src/target/mips_ejtag.h
@@ -38,7 +38,7 @@
 #define EJTAG_INST_TCBCONTROLA	0x10
 #define EJTAG_INST_TCBCONTROLB	0x11
 #define EJTAG_INST_TCBDATA		0x12
-#define EJTAG_INST_BYPASS		0x1F
+#define EJTAG_INST_BYPASS		0xFF
 
 #define EJTAG_CTRL_TOF			(1 << 1)
 #define EJTAG_CTRL_TIF			(1 << 2)
diff --git a/src/target/mips_m4k.c b/src/target/mips_m4k.c
index 0db7a94b..03995b5e 100644
--- a/src/target/mips_m4k.c
+++ b/src/target/mips_m4k.c
@@ -512,7 +512,11 @@ int mips_m4k_read_memory(struct target_s *target, u32 address, u32 size, u32 cou
 		case 4:
 		case 2:
 		case 1:
-			return mips32_pracc_read_mem(ejtag_info, address, size, count, (void *)buffer);
+			/* if noDMA off, use DMAACC mode for memory read */
+			if(ejtag_info->impcode & (1<<14))
+				return mips32_pracc_read_mem(ejtag_info, address, size, count, (void *)buffer);
+			else
+				return mips32_dmaacc_read_mem(ejtag_info, address, size, count, (void *)buffer);
 		default:
 			LOG_ERROR("BUG: we shouldn't get here");
 			exit(-1);
@@ -547,7 +551,11 @@ int mips_m4k_write_memory(struct target_s *target, u32 address, u32 size, u32 co
 		case 4:
 		case 2:
 		case 1:
-			mips32_pracc_write_mem(ejtag_info, address, size, count, (void *)buffer);
+			/* if noDMA off, use DMAACC mode for memory write */
+			if(ejtag_info->impcode & (1<<14))
+				mips32_pracc_write_mem(ejtag_info, address, size, count, (void *)buffer);
+			else
+				mips32_dmaacc_write_mem(ejtag_info, address, size, count, (void *)buffer);
 			break;
 		default:
 			LOG_ERROR("BUG: we shouldn't get here");