Alexei Babich <a.babich@rez.ru> imx31 nand flash controller support

git-svn-id: svn://svn.berlios.de/openocd/trunk@2685 b42882b7-edfa-0310-969c-e2dbd0fdcd60

4 files changed, 1004 insertions, 2 deletions

diff --git a/src/flash/Makefile.am b/src/flash/Makefile.am
index bf39b2e..9a18096 100644
--- a/src/flash/Makefile.am
+++ b/src/flash/Makefile.am
@@ -36,7 +36,8 @@ libflash_la_SOURCES = \
 	ocl.c \
 	mflash.c \
 	pic32mx.c \
-	avrf.c
+	avrf.c \
+	mx3_nand.c
 
 noinst_HEADERS = \
 	arm_nandio.h \
@@ -60,6 +61,7 @@ noinst_HEADERS = \
 	mflash.h \
 	ocl.h \
 	pic32mx.h \
-	avrf.h
+	avrf.h \
+	mx3_nand.h
 
 MAINTAINERCLEANFILES = $(srcdir)/Makefile.in
diff --git a/src/flash/mx3_nand.c b/src/flash/mx3_nand.c
new file mode 100644
index 0000000..8a32bd5
--- /dev/null
+++ b/src/flash/mx3_nand.c
@@ -0,0 +1,908 @@
+
+/***************************************************************************
+ *   Copyright (C) 2009 by Alexei Babich                                   *
+ *   Rezonans plc., Chelyabinsk, Russia                                    *
+ *   impatt@mail.ru                                                        *
+ *                                                                         *
+ *   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.             *
+ ***************************************************************************/
+
+/*
+ * Freescale iMX3* OpenOCD NAND Flash controller support.
+ *
+ * Many thanks to Ben Dooks for writing s3c24xx driver.
+ */
+
+/*
+driver tested with STMicro NAND512W3A @imx31
+tested "nand probe #", "nand erase # 0 #", "nand dump # file 0 #", "nand write # file 0"
+get_next_halfword_from_sram_buffer() not tested
+*/
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "mx3_nand.h"
+
+static const char target_not_halted_err_msg[] =
+	"target must be halted to use mx3 NAND flash controller";
+static const char data_block_size_err_msg[] =
+	"minimal granularity is one half-word, %d is incorrect";
+static const char sram_buffer_bounds_err_msg[] =
+	"trying to access out of SRAM buffer bound (addr=0x%x)";
+static const char invalid_command_sequense_err_msg[] =
+	"invalid command sequence in %s";
+static const char get_status_register_err_msg[] = "can't get NAND status";
+static uint32_t in_sram_address;
+unsigned char sign_of_sequental_byte_read;
+
+static int test_iomux_settings (target_t * target, uint32_t value,
+				uint32_t mask, const char *text);
+static int initialize_nf_controller (struct nand_device_s *device);
+static int get_next_byte_from_sram_buffer (target_t * target, uint8_t * value);
+static int get_next_halfword_from_sram_buffer (target_t * target,
+					       uint16_t * value);
+static int poll_for_complete_op (target_t * target, const char *text);
+static int validate_target_state (struct nand_device_s *device);
+static int do_data_output (struct nand_device_s *device);
+
+static int imx31_nand_device_command (struct command_context_s *cmd_ctx,
+				      char *cmd, char **args, int argc,
+				      struct nand_device_s *device);
+static int imx31_init (struct nand_device_s *device);
+static int imx31_read_data (struct nand_device_s *device, void *data);
+static int imx31_write_data (struct nand_device_s *device, uint16_t data);
+static int imx31_nand_ready (struct nand_device_s *device, int timeout);
+static int imx31_register_commands (struct command_context_s *cmd_ctx);
+static int imx31_reset (struct nand_device_s *device);
+static int imx31_command (struct nand_device_s *device, uint8_t command);
+static int imx31_address (struct nand_device_s *device, uint8_t address);
+static int imx31_controller_ready (struct nand_device_s *device, int tout);
+static int imx31_write_page (struct nand_device_s *device, uint32_t page,
+			     uint8_t * data, uint32_t data_size, uint8_t * oob,
+			     uint32_t oob_size);
+static int imx31_read_page (struct nand_device_s *device, uint32_t page,
+			    uint8_t * data, uint32_t data_size, uint8_t * oob,
+			    uint32_t oob_size);
+
+nand_flash_controller_t imx31_nand_flash_controller = {
+	.name = "imx31",
+	.nand_device_command = imx31_nand_device_command,
+	.register_commands = imx31_register_commands,
+	.init = imx31_init,
+	.reset = imx31_reset,
+	.command = imx31_command,
+	.address = imx31_address,
+	.write_data = imx31_write_data,
+	.read_data = imx31_read_data,
+	.write_page = imx31_write_page,
+	.read_page = imx31_read_page,
+	.controller_ready = imx31_controller_ready,
+	.nand_ready = imx31_nand_ready,
+};
+
+static int imx31_nand_device_command (struct command_context_s *cmd_ctx,
+				      char *cmd, char **args, int argc,
+				      struct nand_device_s *device)
+{
+	mx3_nf_controller_t *mx3_nf_info;
+	mx3_nf_info = malloc (sizeof (mx3_nf_controller_t));
+	if (mx3_nf_info == NULL)
+	{
+	    LOG_ERROR ("no memory for nand controller");
+	    return ERROR_FAIL;
+	}
+
+	device->controller_priv = mx3_nf_info;
+
+	mx3_nf_info->target = get_target (args[1]);
+	if (mx3_nf_info->target == NULL)
+	{
+	    LOG_ERROR ("target '%s' not defined", args[1]);
+	    return ERROR_FAIL;
+	}
+	if (argc < 3)
+	{
+	    LOG_ERROR ("use \"nand device imx31 target noecc|hwecc\"");
+	    return ERROR_FAIL;
+	}
+	/*
+	* check hwecc requirements
+	*/
+	{
+	int hwecc_needed;
+	hwecc_needed = strcmp (args[2], "hwecc");
+	if (hwecc_needed == 0)
+	    {
+		mx3_nf_info->flags.hw_ecc_enabled = 1;
+	    }
+	else
+	    {
+		mx3_nf_info->flags.hw_ecc_enabled = 0;
+	    }
+	}
+
+	mx3_nf_info->optype = MX3_NF_DATAOUT_PAGE;
+	mx3_nf_info->fin = MX3_NF_FIN_NONE;
+	mx3_nf_info->flags.target_little_endian =
+	(mx3_nf_info->target->endianness == TARGET_LITTLE_ENDIAN);
+	/*
+	* testing host endianess
+	*/
+	{
+	int x = 1;
+	if (*(char *) &x == 1)
+	    {
+		mx3_nf_info->flags.host_little_endian = 1;
+	    }
+	else
+	    {
+		mx3_nf_info->flags.host_little_endian = 0;
+	    }
+	}
+	return ERROR_OK;
+}
+
+static int imx31_init (struct nand_device_s *device)
+{
+	mx3_nf_controller_t *mx3_nf_info = device->controller_priv;
+	target_t *target = mx3_nf_info->target;
+
+	{
+	/*
+	 * validate target state
+	 */
+	int validate_target_result;
+	validate_target_result = validate_target_state (device);
+	if (validate_target_result != ERROR_OK)
+	    {
+		return validate_target_result;
+	    }
+	}
+
+	{
+	uint16_t buffsize_register_content;
+	target_read_u16 (target, MX3_NF_BUFSIZ, &buffsize_register_content);
+	mx3_nf_info->flags.one_kb_sram = !(buffsize_register_content & 0x000f);
+	}
+
+	{
+	uint32_t pcsr_register_content;
+	target_read_u32 (target, MX3_PCSR, &pcsr_register_content);
+	if (!device->bus_width)
+	    {
+		device->bus_width =
+		    (pcsr_register_content & 0x80000000) ? 16 : 8;
+	    }
+	else
+	    {
+		pcsr_register_content |=
+		    ((device->bus_width == 16) ? 0x80000000 : 0x00000000);
+		target_write_u32 (target, MX3_PCSR, pcsr_register_content);
+	    }
+
+	if (!device->page_size)
+	    {
+		device->page_size =
+		    (pcsr_register_content & 0x40000000) ? 2048 : 512;
+	    }
+	else
+	    {
+		pcsr_register_content |=
+		    ((device->page_size == 2048) ? 0x40000000 : 0x00000000);
+		target_write_u32 (target, MX3_PCSR, pcsr_register_content);
+	    }
+	if (mx3_nf_info->flags.one_kb_sram && (device->page_size == 2048))
+	    {
+		LOG_ERROR
+		    ("NAND controller have only 1 kb SRAM, so pagesize 2048 is incompatible with it");
+	    }
+	}
+
+	{
+	uint32_t cgr_register_content;
+	target_read_u32 (target, MX3_CCM_CGR2, &cgr_register_content);
+	if (!(cgr_register_content & 0x00000300))
+	    {
+		LOG_ERROR ("clock gating to EMI disabled");
+		return ERROR_FAIL;
+	    }
+	}
+
+	{
+	uint32_t gpr_register_content;
+	target_read_u32 (target, MX3_GPR, &gpr_register_content);
+	if (gpr_register_content & 0x00000060)
+	    {
+		LOG_ERROR ("pins mode overrided by GPR");
+		return ERROR_FAIL;
+	    }
+	}
+
+	{
+	/*
+	 * testing IOMUX settings; must be in "functional-mode output and
+	 * functional-mode input" mode
+	 */
+	uint8_t test_iomux;
+	test_iomux = ERROR_OK;
+	test_iomux |=
+	    test_iomux_settings (target, 0x43fac0c0, 0x7f7f7f00, "d0,d1,d2");
+	test_iomux |=
+	    test_iomux_settings (target, 0x43fac0c4, 0x7f7f7f7f, "d3,d4,d5,d6");
+	test_iomux |=
+	    test_iomux_settings (target, 0x43fac0c8, 0x0000007f, "d7");
+	if (device->bus_width == 16)
+	    {
+		test_iomux |=
+		    test_iomux_settings (target, 0x43fac0c8, 0x7f7f7f00,
+					 "d8,d9,d10");
+		test_iomux |=
+		    test_iomux_settings (target, 0x43fac0cc, 0x7f7f7f7f,
+					 "d11,d12,d13,d14");
+		test_iomux |=
+		    test_iomux_settings (target, 0x43fac0d0, 0x0000007f, "d15");
+	    }
+	test_iomux |=
+	    test_iomux_settings (target, 0x43fac0d0, 0x7f7f7f00,
+				 "nfwp,nfce,nfrb");
+	test_iomux |=
+	    test_iomux_settings (target, 0x43fac0d4, 0x7f7f7f7f,
+				 "nfwe,nfre,nfale,nfcle");
+	if (test_iomux != ERROR_OK)
+	    {
+		return ERROR_FAIL;
+	    }
+	}
+
+	initialize_nf_controller (device);
+
+	{
+	int retval;
+	uint16_t nand_status_content;
+	retval = ERROR_OK;
+	retval |= imx31_command (device, NAND_CMD_STATUS);
+	retval |= imx31_address (device, 0x00);
+	retval |= do_data_output (device);
+	if (retval != ERROR_OK)
+	    {
+		LOG_ERROR (get_status_register_err_msg);
+		return ERROR_FAIL;
+	    }
+	target_read_u16 (target, MX3_NF_MAIN_BUFFER0, &nand_status_content);
+	if (!(nand_status_content & 0x0080))
+	    {
+		/*
+		 * is host-big-endian correctly ??
+		 */
+		LOG_INFO ("NAND read-only");
+		mx3_nf_info->flags.nand_readonly = 1;
+	    }
+	else
+	    {
+		mx3_nf_info->flags.nand_readonly = 0;
+	    }
+	}
+	return ERROR_OK;
+}
+
+static int imx31_read_data (struct nand_device_s *device, void *data)
+{
+	mx3_nf_controller_t *mx3_nf_info = device->controller_priv;
+	target_t *target = mx3_nf_info->target;
+	{
+	/*
+	 * validate target state
+	 */
+	int validate_target_result;
+	validate_target_result = validate_target_state (device);
+	if (validate_target_result != ERROR_OK)
+	    {
+		return validate_target_result;
+	    }
+	}
+
+	{
+	/*
+	 * get data from nand chip
+	 */
+	int try_data_output_from_nand_chip;
+	try_data_output_from_nand_chip = do_data_output (device);
+	if (try_data_output_from_nand_chip != ERROR_OK)
+	    {
+		return try_data_output_from_nand_chip;
+	    }
+	}
+
+	if (device->bus_width == 16)
+	{
+	    get_next_halfword_from_sram_buffer (target, data);
+	}
+	else
+	{
+	    get_next_byte_from_sram_buffer (target, data);
+	}
+
+	return ERROR_OK;
+}
+
+static int imx31_write_data (struct nand_device_s *device, uint16_t data)
+{
+	LOG_ERROR ("write_data() not implemented");
+	return ERROR_NAND_OPERATION_FAILED;
+}
+
+static int imx31_nand_ready (struct nand_device_s *device, int timeout)
+{
+	return imx31_controller_ready (device, timeout);
+}
+
+static int imx31_register_commands (struct command_context_s *cmd_ctx)
+{
+	return ERROR_OK;
+}
+
+static int imx31_reset (struct nand_device_s *device)
+{
+	/*
+	* validate target state
+	*/
+	int validate_target_result;
+	validate_target_result = validate_target_state (device);
+	if (validate_target_result != ERROR_OK)
+	{
+	    return validate_target_result;
+	}
+	initialize_nf_controller (device);
+	return ERROR_OK;
+}
+
+static int imx31_command (struct nand_device_s *device, uint8_t command)
+{
+	mx3_nf_controller_t *mx3_nf_info = device->controller_priv;
+	target_t *target = mx3_nf_info->target;
+	{
+	/*
+	 * validate target state
+	 */
+	int validate_target_result;
+	validate_target_result = validate_target_state (device);
+	if (validate_target_result != ERROR_OK)
+	    {
+		return validate_target_result;
+	    }
+	}
+
+	switch (command)
+	{
+	    case NAND_CMD_READOOB:
+		command = NAND_CMD_READ0;
+		in_sram_address = MX3_NF_SPARE_BUFFER0;	/* set read point for
+							 * data_read() and
+							 * read_block_data() to
+							 * spare area in SRAM
+							 * buffer */
+		break;
+	    case NAND_CMD_READ1:
+		command = NAND_CMD_READ0;
+		/*
+		 * offset == one half of page size
+		 */
+		in_sram_address =
+		    MX3_NF_MAIN_BUFFER0 + (device->page_size >> 1);
+	    default:
+		in_sram_address = MX3_NF_MAIN_BUFFER0;
+	}
+
+	target_write_u16 (target, MX3_NF_FCMD, command);
+	/*
+	* start command input operation (set MX3_NF_BIT_OP_DONE==0)
+	*/
+	target_write_u16 (target, MX3_NF_CFG2, MX3_NF_BIT_OP_FCI);
+	{
+	int poll_result;
+	poll_result = poll_for_complete_op (target, "command");
+	if (poll_result != ERROR_OK)
+	    {
+		return poll_result;
+	    }
+	}
+	/*
+	* reset cursor to begin of the buffer
+	*/
+	sign_of_sequental_byte_read = 0;
+	switch (command)
+	{
+	    case NAND_CMD_READID:
+		mx3_nf_info->optype = MX3_NF_DATAOUT_NANDID;
+		mx3_nf_info->fin = MX3_NF_FIN_DATAOUT;
+		break;
+	    case NAND_CMD_STATUS:
+		mx3_nf_info->optype = MX3_NF_DATAOUT_NANDSTATUS;
+		mx3_nf_info->fin = MX3_NF_FIN_DATAOUT;
+		break;
+	    case NAND_CMD_READ0:
+		mx3_nf_info->fin = MX3_NF_FIN_DATAOUT;
+		mx3_nf_info->optype = MX3_NF_DATAOUT_PAGE;
+		break;
+	    case NAND_CMD_SEQIN:
+		LOG_ERROR ("aaa");
+		return ERROR_FAIL;
+		break;
+	    default:
+		mx3_nf_info->optype = MX3_NF_DATAOUT_PAGE;
+	}
+	return ERROR_OK;
+}
+
+static int imx31_address (struct nand_device_s *device, uint8_t address)
+{
+	mx3_nf_controller_t *mx3_nf_info = device->controller_priv;
+	target_t *target = mx3_nf_info->target;
+	{
+	/*
+	 * validate target state
+	 */
+	int validate_target_result;
+	validate_target_result = validate_target_state (device);
+	if (validate_target_result != ERROR_OK)
+	    {
+		return validate_target_result;
+	    }
+	}
+
+	target_write_u16 (target, MX3_NF_FADDR, address);
+	/*
+	* start address input operation (set MX3_NF_BIT_OP_DONE==0)
+	*/
+	target_write_u16 (target, MX3_NF_CFG2, MX3_NF_BIT_OP_FAI);
+	{
+	int poll_result;
+	poll_result = poll_for_complete_op (target, "address");
+	if (poll_result != ERROR_OK)
+	    {
+		return poll_result;
+	    }
+	}
+	return ERROR_OK;
+}
+
+static int imx31_controller_ready (struct nand_device_s *device, int tout)
+{
+	uint16_t poll_complete_status;
+	mx3_nf_controller_t *mx3_nf_info = device->controller_priv;
+	target_t *target = mx3_nf_info->target;
+
+	{
+	/*
+	 * validate target state
+	 */
+	int validate_target_result;
+	validate_target_result = validate_target_state (device);
+	if (validate_target_result != ERROR_OK)
+	    {
+		return validate_target_result;
+	    }
+	}
+
+	do
+	{
+	    target_read_u16 (target, MX3_NF_CFG2, &poll_complete_status);
+	    if (poll_complete_status & MX3_NF_BIT_OP_DONE)
+		{
+		    return tout;
+		}
+	    alive_sleep (1);
+	}
+	while (tout-- > 0);
+	return tout;
+}
+
+static int imx31_write_page (struct nand_device_s *device, uint32_t page,
+			     uint8_t * data, uint32_t data_size, uint8_t * oob,
+			     uint32_t oob_size)
+{
+	mx3_nf_controller_t *mx3_nf_info = device->controller_priv;
+	target_t *target = mx3_nf_info->target;
+
+	if (data_size % 2)
+	{
+	    LOG_ERROR (data_block_size_err_msg, data_size);
+	    return ERROR_NAND_OPERATION_FAILED;
+	}
+	if (oob_size % 2)
+	{
+	    LOG_ERROR (data_block_size_err_msg, oob_size);
+	    return ERROR_NAND_OPERATION_FAILED;
+	}
+	if (!data)
+	{
+	    LOG_ERROR ("nothing to program");
+	    return ERROR_NAND_OPERATION_FAILED;
+	}
+	{
+	/*
+	 * validate target state
+	 */
+	int retval;
+	retval = validate_target_state (device);
+	if (retval != ERROR_OK)
+	    {
+		return retval;
+	    }
+	}
+	{
+	int retval = ERROR_OK;
+	retval |= imx31_command (device, NAND_CMD_SEQIN);
+	retval |= imx31_address (device, 0x00);
+	retval |= imx31_address (device, page & 0xff);
+	retval |= imx31_address (device, (page >> 8) & 0xff);
+	if (device->address_cycles >= 4)
+	    {
+		retval |= imx31_address (device, (page >> 16) & 0xff);
+		if (device->address_cycles >= 5)
+		    {
+			retval |= imx31_address (device, (page >> 24) & 0xff);
+		    }
+	    }
+	target_write_buffer (target, MX3_NF_MAIN_BUFFER0, data_size, data);
+	if (oob)
+	    {
+		if (mx3_nf_info->flags.hw_ecc_enabled)
+		    {
+			/*
+			 * part of spare block will be overrided by hardware
+			 * ECC generator
+			 */
+			LOG_DEBUG
+			    ("part of spare block will be overrided by hardware ECC generator");
+		    }
+		target_write_buffer (target, MX3_NF_SPARE_BUFFER0, oob_size,
+				     oob);
+	    }
+	/*
+	 * start data input operation (set MX3_NF_BIT_OP_DONE==0)
+	 */
+	target_write_u16 (target, MX3_NF_CFG2, MX3_NF_BIT_OP_FDI);
+	{
+	    int poll_result;
+	    poll_result = poll_for_complete_op (target, "data input");
+	    if (poll_result != ERROR_OK)
+		{
+		    return poll_result;
+		}
+	}
+	retval |= imx31_command (device, NAND_CMD_PAGEPROG);
+	if (retval != ERROR_OK)
+	    {
+		return retval;
+	    }
+
+	/*
+	 * check status register
+	 */
+	{
+	    uint16_t nand_status_content;
+	    retval = ERROR_OK;
+	    retval |= imx31_command (device, NAND_CMD_STATUS);
+	    retval |= imx31_address (device, 0x00);
+	    retval |= do_data_output (device);
+	    if (retval != ERROR_OK)
+		{
+		    LOG_ERROR (get_status_register_err_msg);
+		    return retval;
+		}
+	    target_read_u16 (target, MX3_NF_MAIN_BUFFER0, &nand_status_content);
+	    if (nand_status_content & 0x0001)
+		{
+		    /*
+		     * is host-big-endian correctly ??
+		     */
+		    return ERROR_NAND_OPERATION_FAILED;
+		}
+	}
+	}
+	return ERROR_OK;
+}
+
+static int imx31_read_page (struct nand_device_s *device, uint32_t page,
+			    uint8_t * data, uint32_t data_size, uint8_t * oob,
+			    uint32_t oob_size)
+{
+	mx3_nf_controller_t *mx3_nf_info = device->controller_priv;
+	target_t *target = mx3_nf_info->target;
+
+	if (data_size % 2)
+	{
+	    LOG_ERROR (data_block_size_err_msg, data_size);
+	    return ERROR_NAND_OPERATION_FAILED;
+	}
+	if (oob_size % 2)
+	{
+	    LOG_ERROR (data_block_size_err_msg, oob_size);
+	    return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	{
+	/*
+	 * validate target state
+	 */
+	int retval;
+	retval = validate_target_state (device);
+	if (retval != ERROR_OK)
+	    {
+		return retval;
+	    }
+	}
+	{
+	int retval = ERROR_OK;
+	retval |= imx31_command (device, NAND_CMD_READ0);
+	retval |= imx31_address (device, 0x00);
+	retval |= imx31_address (device, page & 0xff);
+	retval |= imx31_address (device, (page >> 8) & 0xff);
+	if (device->address_cycles >= 4)
+	    {
+		retval |= imx31_address (device, (page >> 16) & 0xff);
+		if (device->address_cycles >= 5)
+		    {
+			retval |= imx31_address (device, (page >> 24) & 0xff);
+			retval |= imx31_command (device, NAND_CMD_READSTART);
+		    }
+	    }
+	retval |= do_data_output (device);
+	if (retval != ERROR_OK)
+	    {
+		return retval;
+	    }
+
+	if (data)
+	    {
+		target_read_buffer (target, MX3_NF_MAIN_BUFFER0, data_size,
+				    data);
+	    }
+	if (oob)
+	    {
+		target_read_buffer (target, MX3_NF_SPARE_BUFFER0, oob_size,
+				    oob);
+	    }
+	}
+	return ERROR_OK;
+}
+
+static int test_iomux_settings (target_t * target, uint32_t address,
+				uint32_t mask, const char *text)
+{
+	uint32_t register_content;
+	target_read_u32 (target, address, &register_content);
+	if ((register_content & mask) != (0x12121212 & mask))
+	{
+	    LOG_ERROR ("IOMUX for {%s} is bad", text);
+	    return ERROR_FAIL;
+	}
+	return ERROR_OK;
+}
+
+static int initialize_nf_controller (struct nand_device_s *device)
+{
+	mx3_nf_controller_t *mx3_nf_info = device->controller_priv;
+	target_t *target = mx3_nf_info->target;
+	/*
+	* resets NAND flash controller in zero time ? I dont know.
+	*/
+	target_write_u16 (target, MX3_NF_CFG1, MX3_NF_BIT_RESET_EN);
+	{
+	uint16_t work_mode;
+	work_mode = MX3_NF_BIT_INT_DIS;	/* disable interrupt */
+	if (target->endianness == TARGET_BIG_ENDIAN)
+	    {
+		work_mode |= MX3_NF_BIT_BE_EN;
+	    }
+	if (mx3_nf_info->flags.hw_ecc_enabled)
+	    {
+		work_mode |= MX3_NF_BIT_ECC_EN;
+	    }
+	target_write_u16 (target, MX3_NF_CFG1, work_mode);
+	}
+	/*
+	* unlock SRAM buffer for write; 2 mean "Unlock", other values means "Lock"
+	*/
+	target_write_u16 (target, MX3_NF_BUFCFG, 2);
+	{
+	uint16_t temp;
+	target_read_u16 (target, MX3_NF_FWP, &temp);
+	if ((temp & 0x0007) == 1)
+	    {
+		LOG_ERROR ("NAND flash is tight-locked, reset needed");
+		return ERROR_FAIL;
+	    }
+
+	}
+	/*
+	* unlock NAND flash for write
+	*/
+	target_write_u16 (target, MX3_NF_FWP, 4);
+	target_write_u16 (target, MX3_NF_LOCKSTART, 0x0000);
+	target_write_u16 (target, MX3_NF_LOCKEND, 0xFFFF);
+	/*
+	* 0x0000 means that first SRAM buffer @0xB800_0000 will be used
+	*/
+	target_write_u16 (target, MX3_NF_BUFADDR, 0x0000);
+	/*
+	* address of SRAM buffer
+	*/
+	in_sram_address = MX3_NF_MAIN_BUFFER0;
+	sign_of_sequental_byte_read = 0;
+	return ERROR_OK;
+}
+
+static int get_next_byte_from_sram_buffer (target_t * target, uint8_t * value)
+{
+	static uint8_t even_byte = 0;
+	/*
+	* host-big_endian ??
+	*/
+	if (sign_of_sequental_byte_read == 0)
+	{
+	    even_byte = 0;
+	}
+	if (in_sram_address > MX3_NF_LAST_BUFFER_ADDR)
+	{
+	    LOG_ERROR (sram_buffer_bounds_err_msg, in_sram_address);
+	    *value = 0;
+	    sign_of_sequental_byte_read = 0;
+	    even_byte = 0;
+	    return ERROR_NAND_OPERATION_FAILED;
+	}
+	else
+	{
+	    uint16_t temp;
+	    target_read_u16 (target, in_sram_address, &temp);
+	    if (even_byte)
+		{
+		    *value = temp >> 8;
+		    even_byte = 0;
+		    in_sram_address += 2;
+		}
+	    else
+		{
+		    *value = temp & 0xff;
+		    even_byte = 1;
+		}
+	}
+	sign_of_sequental_byte_read = 1;
+	return ERROR_OK;
+}
+
+static int get_next_halfword_from_sram_buffer (target_t * target,
+					       uint16_t * value)
+{
+	if (in_sram_address > MX3_NF_LAST_BUFFER_ADDR)
+	{
+	    LOG_ERROR (sram_buffer_bounds_err_msg, in_sram_address);
+	    *value = 0;
+	    return ERROR_NAND_OPERATION_FAILED;
+	}
+	else
+	{
+	    target_read_u16 (target, in_sram_address, value);
+	    in_sram_address += 2;
+	}
+	return ERROR_OK;
+}
+
+static int poll_for_complete_op (target_t * target, const char *text)
+{
+	uint16_t poll_complete_status;
+	for (int poll_cycle_count = 0; poll_cycle_count < 100; poll_cycle_count++)
+	{
+	    usleep (25);
+	    target_read_u16 (target, MX3_NF_CFG2, &poll_complete_status);
+	    if (poll_complete_status & MX3_NF_BIT_OP_DONE)
+		{
+		    break;
+		}
+	}
+	if (!(poll_complete_status & MX3_NF_BIT_OP_DONE))
+	{
+	    LOG_ERROR ("%s sending timeout", text);
+	    return ERROR_NAND_OPERATION_FAILED;
+	}
+	return ERROR_OK;
+}
+
+static int validate_target_state (struct nand_device_s *device)
+{
+	mx3_nf_controller_t *mx3_nf_info = device->controller_priv;
+	target_t *target = mx3_nf_info->target;
+
+	if (target->state != TARGET_HALTED)
+	{
+	    LOG_ERROR (target_not_halted_err_msg);
+	    return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	if (mx3_nf_info->flags.target_little_endian !=
+	(target->endianness == TARGET_LITTLE_ENDIAN))
+	{
+	    /*
+	     * endianness changed after NAND controller probed
+	     */
+	    return ERROR_NAND_OPERATION_FAILED;
+	}
+	return ERROR_OK;
+}
+
+static int do_data_output (struct nand_device_s *device)
+{
+	mx3_nf_controller_t *mx3_nf_info = device->controller_priv;
+	target_t *target = mx3_nf_info->target;
+	switch (mx3_nf_info->fin)
+	{
+	    case MX3_NF_FIN_DATAOUT:
+		/*
+		 * start data output operation (set MX3_NF_BIT_OP_DONE==0)
+		 */
+		target_write_u16 (target, MX3_NF_CFG2,
+				  MX3_NF_BIT_DATAOUT_TYPE (mx3_nf_info->
+							   optype));
+		{
+		    int poll_result;
+		    poll_result = poll_for_complete_op (target, "data output");
+		    if (poll_result != ERROR_OK)
+			{
+			    return poll_result;
+			}
+		}
+		mx3_nf_info->fin = MX3_NF_FIN_NONE;
+		/*
+		 * ECC stuff
+		 */
+		if ((mx3_nf_info->optype == MX3_NF_DATAOUT_PAGE)
+		    && mx3_nf_info->flags.hw_ecc_enabled)
+		    {
+			uint16_t ecc_status;
+			target_read_u16 (target, MX3_NF_ECCSTATUS, &ecc_status);
+			switch (ecc_status & 0x000c)
+			    {
+				case 1 << 2:
+				    LOG_DEBUG
+					("main area readed with 1 (correctable) error");
+				    break;
+				case 2 << 2:
+				    LOG_DEBUG
+					("main area readed with more than 1 (incorrectable) error");
+				    return ERROR_NAND_OPERATION_FAILED;
+				    break;
+			    }
+			switch (ecc_status & 0x0003)
+			    {
+				case 1:
+				    LOG_DEBUG
+					("spare area readed with 1 (correctable) error");
+				    break;
+				case 2:
+				    LOG_DEBUG
+					("main area readed with more than 1 (incorrectable) error");
+				    return ERROR_NAND_OPERATION_FAILED;
+				    break;
+			    }
+		    }
+		break;
+	    case MX3_NF_FIN_NONE:
+		break;
+	}
+	return ERROR_OK;
+}
diff --git a/src/flash/mx3_nand.h b/src/flash/mx3_nand.h
new file mode 100644
index 0000000..2759fde
--- /dev/null
+++ b/src/flash/mx3_nand.h
@@ -0,0 +1,90 @@
+#include <nand.h>
+
+#define		MX3_NF_BASE_ADDR		0xb8000000
+#define		MX3_NF_BUFSIZ			(MX3_NF_BASE_ADDR + 0xe00)
+#define		MX3_NF_BUFADDR			(MX3_NF_BASE_ADDR + 0xe04)
+#define		MX3_NF_FADDR			(MX3_NF_BASE_ADDR + 0xe06)
+#define		MX3_NF_FCMD				(MX3_NF_BASE_ADDR + 0xe08)
+#define		MX3_NF_BUFCFG			(MX3_NF_BASE_ADDR + 0xe0a)
+#define		MX3_NF_ECCSTATUS			(MX3_NF_BASE_ADDR + 0xe0c)
+#define		MX3_NF_ECCMAINPOS			(MX3_NF_BASE_ADDR + 0xe0e)
+#define		MX3_NF_ECCSPAREPOS			(MX3_NF_BASE_ADDR + 0xe10)
+#define		MX3_NF_FWP			(MX3_NF_BASE_ADDR + 0xe12)
+#define		MX3_NF_LOCKSTART			(MX3_NF_BASE_ADDR + 0xe14)
+#define		MX3_NF_LOCKEND			(MX3_NF_BASE_ADDR + 0xe16)
+#define		MX3_NF_FWPSTATUS			(MX3_NF_BASE_ADDR + 0xe18)
+ /*
+  * all bits not marked as self-clearing bit
+  */
+#define		MX3_NF_CFG1			(MX3_NF_BASE_ADDR + 0xe1a)
+#define		MX3_NF_CFG2			(MX3_NF_BASE_ADDR + 0xe1c)
+
+#define		MX3_NF_MAIN_BUFFER0		(MX3_NF_BASE_ADDR + 0x0000)
+#define		MX3_NF_MAIN_BUFFER1		(MX3_NF_BASE_ADDR + 0x0200)
+#define		MX3_NF_MAIN_BUFFER2		(MX3_NF_BASE_ADDR + 0x0400)
+#define		MX3_NF_MAIN_BUFFER3		(MX3_NF_BASE_ADDR + 0x0600)
+#define		MX3_NF_SPARE_BUFFER0	(MX3_NF_BASE_ADDR + 0x0800)
+#define		MX3_NF_SPARE_BUFFER1	(MX3_NF_BASE_ADDR + 0x0810)
+#define		MX3_NF_SPARE_BUFFER2	(MX3_NF_BASE_ADDR + 0x0820)
+#define		MX3_NF_SPARE_BUFFER3	(MX3_NF_BASE_ADDR + 0x0830)
+#define		MX3_NF_MAIN_BUFFER_LEN	512
+#define		MX3_NF_SPARE_BUFFER_LEN	16
+#define		MX3_NF_LAST_BUFFER_ADDR	((MX3_NF_SPARE_BUFFER3) + MX3_NF_SPARE_BUFFER_LEN - 2)
+
+/* bits in MX3_NF_CFG1 register */
+#define		MX3_NF_BIT_SPARE_ONLY_EN	(1<<2)
+#define		MX3_NF_BIT_ECC_EN			(1<<3)
+#define		MX3_NF_BIT_INT_DIS			(1<<4)
+#define		MX3_NF_BIT_BE_EN			(1<<5)
+#define		MX3_NF_BIT_RESET_EN			(1<<6)
+#define		MX3_NF_BIT_FORCE_CE			(1<<7)
+
+/* bits in MX3_NF_CFG2 register */
+
+/*Flash Command Input*/
+#define		MX3_NF_BIT_OP_FCI			(1<<0)
+ /*
+  * Flash Address Input
+  */
+#define		MX3_NF_BIT_OP_FAI			(1<<1)
+ /*
+  * Flash Data Input
+  */
+#define		MX3_NF_BIT_OP_FDI			(1<<2)
+
+/* see "enum mx_dataout_type" below */
+#define		MX3_NF_BIT_DATAOUT_TYPE(x)	((x)<<3)
+#define		MX3_NF_BIT_OP_DONE			(1<<15)
+
+#define		MX3_CCM_CGR2		0x53f80028
+#define		MX3_GPR				0x43fac008
+#define		MX3_PCSR			0x53f8000c
+
+enum mx_dataout_type
+{
+	MX3_NF_DATAOUT_PAGE = 1,
+	MX3_NF_DATAOUT_NANDID = 2,
+	MX3_NF_DATAOUT_NANDSTATUS = 4,
+};
+enum mx_nf_finalize_action
+{
+	MX3_NF_FIN_NONE,
+	MX3_NF_FIN_DATAOUT,
+};
+
+struct mx3_nf_flags
+{
+	unsigned host_little_endian:1;
+	unsigned target_little_endian:1;
+	unsigned nand_readonly:1;
+	unsigned one_kb_sram:1;
+	unsigned hw_ecc_enabled:1;
+};
+
+typedef struct mx3_nf_controller_s
+{
+	struct target_s *target;
+	enum mx_dataout_type optype;
+	enum mx_nf_finalize_action fin;
+	struct mx3_nf_flags flags;
+} mx3_nf_controller_t;
diff --git a/src/flash/nand.c b/src/flash/nand.c
index f272241..84ed0a4 100644
--- a/src/flash/nand.c
+++ b/src/flash/nand.c
@@ -52,6 +52,7 @@ extern nand_flash_controller_t s3c2410_nand_controller;
 extern nand_flash_controller_t s3c2412_nand_controller;
 extern nand_flash_controller_t s3c2440_nand_controller;
 extern nand_flash_controller_t s3c2443_nand_controller;
+extern nand_flash_controller_t imx31_nand_flash_controller;
 
 /* extern nand_flash_controller_t boundary_scan_nand_controller; */
 
@@ -64,6 +65,7 @@ static nand_flash_controller_t *nand_flash_controllers[] =
 	&s3c2412_nand_controller,
 	&s3c2440_nand_controller,
 	&s3c2443_nand_controller,
+ 	&imx31_nand_flash_controller,
 /*	&boundary_scan_nand_controller, */
 	NULL
 };