NAND support for zylonite board + some minor cleanup.

4 files changed, 589 insertions, 3 deletions

diff --git a/board/zylonite/Makefile b/board/zylonite/Makefile
index 999647f..f3ad674 100644
--- a/board/zylonite/Makefile
+++ b/board/zylonite/Makefile
@@ -1,4 +1,3 @@
-
 #
 # (C) Copyright 2000
 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
@@ -21,12 +20,11 @@
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 # MA 02111-1307 USA
 #
-
 include $(TOPDIR)/config.mk
 
 LIB	= lib$(BOARD).a
 
-OBJS	:= zylonite.o flash.o
+OBJS	:= zylonite.o nand.o
 SOBJS	:= lowlevel_init.o
 
 $(LIB):	$(OBJS) $(SOBJS)
diff --git a/board/zylonite/config.mk b/board/zylonite/config.mk
index 09b0f71..b5d5955 100644
--- a/board/zylonite/config.mk
+++ b/board/zylonite/config.mk
@@ -2,3 +2,5 @@
 #TEXT_BASE = 0xa1700000
 #TEXT_BASE = 0xa3080000
 TEXT_BASE = 0xa3008000
+
+BOARDLIBS = drivers/nand/libnand.a
diff --git a/board/zylonite/lowlevel_init.S b/board/zylonite/lowlevel_init.S
index c3bb4eb..da01765 100644
--- a/board/zylonite/lowlevel_init.S
+++ b/board/zylonite/lowlevel_init.S
@@ -235,6 +235,7 @@ mem_init:
 	orr		r1, r1, #0x40000000	@ enable SDRAM for Normal Access
 	str		r1, [r0]
 
+#ifndef CFG_SKIP_DRAM_SCRUB
 	/* scrub/init SDRAM if enabled/present */
 /*	ldr	r11, =0xa0000000 /\* base address of SDRAM (CFG_DRAM_BASE) *\/ */
 /*	ldr	r12, =0x04000000 /\* size of memory to scrub (CFG_DRAM_SIZE) *\/ */
@@ -254,6 +255,7 @@ mem_init:
 	stmia	r8!, {r0-r7}
 	beq	15f
 	b	10b
+#endif /* CFG_SKIP_DRAM_SCRUB */
 
 15:
 	/* Mask all interrupts */
diff --git a/board/zylonite/nand.c b/board/zylonite/nand.c
new file mode 100644
index 0000000..5d2cd65
--- /dev/null
+++ b/board/zylonite/nand.c
@@ -0,0 +1,584 @@
+/*
+ * (C) Copyright 2006 DENX Software Engineering
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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
+ */
+
+#include <common.h>
+
+#if (CONFIG_COMMANDS & CFG_CMD_NAND)
+#ifdef CONFIG_NEW_NAND_CODE
+
+#include <nand.h>
+#include <asm/arch/pxa-regs.h>
+
+#ifdef CFG_DFC_DEBUG1
+# define DFC_DEBUG1(fmt, args...) printf(fmt, ##args)
+#else
+# define DFC_DEBUG1(fmt, args...)
+#endif
+
+#ifdef CFG_DFC_DEBUG2
+# define DFC_DEBUG2(fmt, args...) printf(fmt, ##args)
+#else
+# define DFC_DEBUG2(fmt, args...)
+#endif
+
+#ifdef CFG_DFC_DEBUG3
+# define DFC_DEBUG3(fmt, args...) printf(fmt, ##args)
+#else
+# define DFC_DEBUG3(fmt, args...)
+#endif
+
+#define MIN(x, y)		((x < y) ? x : y)
+
+/* These really don't belong here, as they are specific to the NAND Model */
+static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
+
+static struct nand_bbt_descr delta_bbt_descr = {
+	.options = 0,
+	.offs = 0,
+	.len = 2,
+	.pattern = scan_ff_pattern
+};
+
+static struct nand_oobinfo delta_oob = {
+	.useecc = MTD_NANDECC_AUTOPL_USR, /* MTD_NANDECC_PLACEONLY, */
+	.eccbytes = 6,
+	.eccpos = {2, 3, 4, 5, 6, 7},
+	.oobfree = { {8, 2}, {12, 4} }
+};
+
+
+/*
+ * not required for Monahans DFC
+ */
+static void dfc_hwcontrol(struct mtd_info *mtdinfo, int cmd)
+{
+	return;
+}
+
+#if 0
+/* read device ready pin */
+static int dfc_device_ready(struct mtd_info *mtdinfo)
+{
+	if(NDSR & NDSR_RDY)
+		return 1;
+	else
+		return 0;
+	return 0;
+}
+#endif
+
+/*
+ * Write buf to the DFC Controller Data Buffer
+ */
+static void dfc_write_buf(struct mtd_info *mtd, const u_char *buf, int len)
+{
+	unsigned long bytes_multi = len & 0xfffffffc;
+	unsigned long rest = len & 0x3;
+	unsigned long *long_buf;
+	int i;
+
+	DFC_DEBUG2("dfc_write_buf: writing %d bytes starting with 0x%x.\n", len, *((unsigned long*) buf));
+	if(bytes_multi) {
+		for(i=0; i<bytes_multi; i+=4) {
+			long_buf = (unsigned long*) &buf[i];
+			NDDB = *long_buf;
+		}
+	}
+	if(rest) {
+		printf("dfc_write_buf: ERROR, writing non 4-byte aligned data.\n");
+	}
+	return;
+}
+
+
+/*
+ * These functions are quite problematic for the DFC. Luckily they are
+ * not used in the current nand code, except for nand_command, which
+ * we've defined our own anyway. The problem is, that we always need
+ * to write 4 bytes to the DFC Data Buffer, but in these functions we
+ * don't know if to buffer the bytes/half words until we've gathered 4
+ * bytes or if to send them straight away.
+ *
+ * Solution: Don't use these with Mona's DFC and complain loudly.
+ */
+static void dfc_write_word(struct mtd_info *mtd, u16 word)
+{
+	printf("dfc_write_word: WARNING, this function does not work with the Monahans DFC!\n");
+}
+static void dfc_write_byte(struct mtd_info *mtd, u_char byte)
+{
+	printf("dfc_write_byte: WARNING, this function does not work with the Monahans DFC!\n");
+}
+
+/* The original:
+ * static void dfc_read_buf(struct mtd_info *mtd, const u_char *buf, int len)
+ *
+ * Shouldn't this be "u_char * const buf" ?
+ */
+static void dfc_read_buf(struct mtd_info *mtd, u_char* const buf, int len)
+{
+	int i=0, j;
+
+	/* we have to be carefull not to overflow the buffer if len is
+	 * not a multiple of 4 */
+	unsigned long bytes_multi = len & 0xfffffffc;
+	unsigned long rest = len & 0x3;
+	unsigned long *long_buf;
+
+	DFC_DEBUG3("dfc_read_buf: reading %d bytes.\n", len);
+	/* if there are any, first copy multiple of 4 bytes */
+	if(bytes_multi) {
+		for(i=0; i<bytes_multi; i+=4) {
+			long_buf = (unsigned long*) &buf[i];
+			*long_buf = NDDB;
+		}
+	}
+
+	/* ...then the rest */
+	if(rest) {
+		unsigned long rest_data = NDDB;
+		for(j=0;j<rest; j++)
+			buf[i+j] = (u_char) ((rest_data>>j) & 0xff);
+	}
+
+	return;
+}
+
+/*
+ * read a word. Not implemented as not used in NAND code.
+ */
+static u16 dfc_read_word(struct mtd_info *mtd)
+{
+	printf("dfc_write_byte: UNIMPLEMENTED.\n");
+	return 0;
+}
+
+/* global var, too bad: mk@tbd: move to ->priv pointer */
+static unsigned long read_buf = 0;
+static int bytes_read = -1;
+
+/*
+ * read a byte from NDDB Because we can only read 4 bytes from NDDB at
+ * a time, we buffer the remaining bytes. The buffer is reset when a
+ * new command is sent to the chip.
+ *
+ * WARNING:
+ * This function is currently only used to read status and id
+ * bytes. For these commands always 8 bytes need to be read from
+ * NDDB. So we read and discard these bytes right now. In case this
+ * function is used for anything else in the future, we must check
+ * what was the last command issued and read the appropriate amount of
+ * bytes respectively.
+ */
+static u_char dfc_read_byte(struct mtd_info *mtd)
+{
+	unsigned char byte;
+	unsigned long dummy;
+
+	if(bytes_read < 0) {
+		read_buf = NDDB;
+		dummy = NDDB;
+		bytes_read = 0;
+	}
+	byte = (unsigned char) (read_buf>>(8 * bytes_read++));
+	if(bytes_read >= 4)
+		bytes_read = -1;
+
+	DFC_DEBUG2("dfc_read_byte: byte %u: 0x%x of (0x%x).\n", bytes_read - 1, byte, read_buf);
+	return byte;
+}
+
+/* calculate delta between OSCR values start and now  */
+static unsigned long get_delta(unsigned long start)
+{
+	unsigned long cur = OSCR;
+
+	if(cur < start) /* OSCR overflowed */
+		return (cur + (start^0xffffffff));
+	else
+		return (cur - start);
+}
+
+/* delay function, this doesn't belong here */
+static void wait_us(unsigned long us)
+{
+	unsigned long start = OSCR;
+	us *= OSCR_CLK_FREQ;
+
+	while (get_delta(start) < us) {
+		/* do nothing */
+	}
+}
+
+static void dfc_clear_nddb(void)
+{
+	NDCR &= ~NDCR_ND_RUN;
+	wait_us(CFG_NAND_OTHER_TO);
+}
+
+/* wait_event with timeout */
+static unsigned long dfc_wait_event(unsigned long event)
+{
+	unsigned long ndsr, timeout, start = OSCR;
+
+	if(!event)
+		return 0xff000000;
+	else if(event & (NDSR_CS0_CMDD | NDSR_CS0_BBD))
+		timeout = CFG_NAND_PROG_ERASE_TO * OSCR_CLK_FREQ;
+	else
+		timeout = CFG_NAND_OTHER_TO * OSCR_CLK_FREQ;
+
+	while(1) {
+		ndsr = NDSR;
+		if(ndsr & event) {
+			NDSR |= event;
+			break;
+		}
+		if(get_delta(start) > timeout) {
+			DFC_DEBUG1("dfc_wait_event: TIMEOUT waiting for event: 0x%x.\n", event);
+			return 0xff000000;
+		}
+
+	}
+	return ndsr;
+}
+
+/* we don't always wan't to do this */
+static void dfc_new_cmd(void)
+{
+	int retry = 0;
+	unsigned long status;
+
+	while(retry++ <= CFG_NAND_SENDCMD_RETRY) {
+		/* Clear NDSR */
+		NDSR = 0xFFF;
+
+		/* set NDCR[NDRUN] */
+		if(!(NDCR & NDCR_ND_RUN))
+			NDCR |= NDCR_ND_RUN;
+
+		status = dfc_wait_event(NDSR_WRCMDREQ);
+
+		if(status & NDSR_WRCMDREQ)
+			return;
+
+		DFC_DEBUG2("dfc_new_cmd: FAILED to get WRITECMDREQ, retry: %d.\n", retry);
+		dfc_clear_nddb();
+	}
+	DFC_DEBUG1("dfc_new_cmd: giving up after %d retries.\n", retry);
+}
+
+/* this function is called after Programm and Erase Operations to
+ * check for success or failure */
+static int dfc_wait(struct mtd_info *mtd, struct nand_chip *this, int state)
+{
+	unsigned long ndsr=0, event=0;
+
+	if(state == FL_WRITING) {
+		event = NDSR_CS0_CMDD | NDSR_CS0_BBD;
+	} else if(state == FL_ERASING) {
+		event = NDSR_CS0_CMDD | NDSR_CS0_BBD;
+	}
+
+	ndsr = dfc_wait_event(event);
+
+	if((ndsr & NDSR_CS0_BBD) || (ndsr & 0xff000000))
+		return(0x1); /* Status Read error */
+	return 0;
+}
+
+/* cmdfunc send commands to the DFC */
+static void dfc_cmdfunc(struct mtd_info *mtd, unsigned command,
+			int column, int page_addr)
+{
+	/* register struct nand_chip *this = mtd->priv; */
+	unsigned long ndcb0=0, ndcb1=0, ndcb2=0, event=0;
+
+	/* clear the ugly byte read buffer */
+	bytes_read = -1;
+	read_buf = 0;
+
+	switch (command) {
+	case NAND_CMD_READ0:
+		DFC_DEBUG3("dfc_cmdfunc: NAND_CMD_READ0, page_addr: 0x%x, column: 0x%x.\n", page_addr, (column>>1));
+		dfc_new_cmd();
+		ndcb0 = (NAND_CMD_READ0 | (4<<16));
+		column >>= 1; /* adjust for 16 bit bus */
+		ndcb1 = (((column>>1) & 0xff) |
+			 ((page_addr<<8) & 0xff00) |
+			 ((page_addr<<8) & 0xff0000) |
+			 ((page_addr<<8) & 0xff000000)); /* make this 0x01000000 ? */
+		event = NDSR_RDDREQ;
+		goto write_cmd;
+	case NAND_CMD_READ1:
+		DFC_DEBUG2("dfc_cmdfunc: NAND_CMD_READ1 unimplemented!\n");
+		goto end;
+	case NAND_CMD_READOOB:
+		DFC_DEBUG1("dfc_cmdfunc: NAND_CMD_READOOB unimplemented!\n");
+		goto end;
+	case NAND_CMD_READID:
+		dfc_new_cmd();
+		DFC_DEBUG2("dfc_cmdfunc: NAND_CMD_READID.\n");
+		ndcb0 = (NAND_CMD_READID | (3 << 21) | (1 << 16)); /* addr cycles*/
+		event = NDSR_RDDREQ;
+		goto write_cmd;
+	case NAND_CMD_PAGEPROG:
+		/* sent as a multicommand in NAND_CMD_SEQIN */
+		DFC_DEBUG2("dfc_cmdfunc: NAND_CMD_PAGEPROG empty due to multicmd.\n");
+		goto end;
+	case NAND_CMD_ERASE1:
+		DFC_DEBUG2("dfc_cmdfunc: NAND_CMD_ERASE1,  page_addr: 0x%x, column: 0x%x.\n", page_addr, (column>>1));
+		dfc_new_cmd();
+		ndcb0 = (0xd060 | (1<<25) | (2<<21) | (1<<19) | (3<<16));
+		ndcb1 = (page_addr & 0x00ffffff);
+		goto write_cmd;
+	case NAND_CMD_ERASE2:
+		DFC_DEBUG2("dfc_cmdfunc: NAND_CMD_ERASE2 empty due to multicmd.\n");
+		goto end;
+	case NAND_CMD_SEQIN:
+		/* send PAGE_PROG command(0x1080) */
+		dfc_new_cmd();
+		DFC_DEBUG2("dfc_cmdfunc: NAND_CMD_SEQIN/PAGE_PROG,  page_addr: 0x%x, column: 0x%x.\n", page_addr, (column>>1));
+		ndcb0 = (0x1080 | (1<<25) | (1<<21) | (1<<19) | (4<<16));
+		column >>= 1; /* adjust for 16 bit bus */
+		ndcb1 = (((column>>1) & 0xff) |
+			 ((page_addr<<8) & 0xff00) |
+			 ((page_addr<<8) & 0xff0000) |
+			 ((page_addr<<8) & 0xff000000)); /* make this 0x01000000 ? */
+		event = NDSR_WRDREQ;
+		goto write_cmd;
+	case NAND_CMD_STATUS:
+		DFC_DEBUG2("dfc_cmdfunc: NAND_CMD_STATUS.\n");
+		dfc_new_cmd();
+		ndcb0 = NAND_CMD_STATUS | (4<<21);
+		event = NDSR_RDDREQ;
+		goto write_cmd;
+	case NAND_CMD_RESET:
+		DFC_DEBUG2("dfc_cmdfunc: NAND_CMD_RESET.\n");
+		ndcb0 = NAND_CMD_RESET | (5<<21);
+		event = NDSR_CS0_CMDD;
+		goto write_cmd;
+	default:
+		printk("dfc_cmdfunc: error, unsupported command.\n");
+		goto end;
+	}
+
+ write_cmd:
+	NDCB0 = ndcb0;
+	NDCB0 = ndcb1;
+	NDCB0 = ndcb2;
+
+	/*  wait_event: */
+	dfc_wait_event(event);
+ end:
+	return;
+}
+
+static void dfc_gpio_init(void)
+{
+	DFC_DEBUG2("Setting up DFC GPIO's.\n");
+
+	/* no idea what is done here, see zylonite.c */
+	GPIO4 = 0x1;
+
+	DF_ALE_WE1 = 0x00000001;
+	DF_ALE_WE2 = 0x00000001;
+	DF_nCS0 = 0x00000001;
+	DF_nCS1 = 0x00000001;
+	DF_nWE = 0x00000001;
+	DF_nRE = 0x00000001;
+	DF_IO0 = 0x00000001;
+	DF_IO8 = 0x00000001;
+	DF_IO1 = 0x00000001;
+	DF_IO9 = 0x00000001;
+	DF_IO2 = 0x00000001;
+	DF_IO10 = 0x00000001;
+	DF_IO3 = 0x00000001;
+	DF_IO11 = 0x00000001;
+	DF_IO4 = 0x00000001;
+	DF_IO12 = 0x00000001;
+	DF_IO5 = 0x00000001;
+	DF_IO13 = 0x00000001;
+	DF_IO6 = 0x00000001;
+	DF_IO14 = 0x00000001;
+	DF_IO7 = 0x00000001;
+	DF_IO15 = 0x00000001;
+
+	DF_nWE = 0x1901;
+	DF_nRE = 0x1901;
+	DF_CLE_NOE = 0x1900;
+	DF_ALE_WE1 = 0x1901;
+	DF_INT_RnB = 0x1900;
+}
+
+/*
+ * Board-specific NAND initialization. The following members of the
+ * argument are board-specific (per include/linux/mtd/nand_new.h):
+ * - IO_ADDR_R?: address to read the 8 I/O lines of the flash device
+ * - IO_ADDR_W?: address to write the 8 I/O lines of the flash device
+ * - hwcontrol: hardwarespecific function for accesing control-lines
+ * - dev_ready: hardwarespecific function for  accesing device ready/busy line
+ * - enable_hwecc?: function to enable (reset)  hardware ecc generator. Must
+ *   only be provided if a hardware ECC is available
+ * - eccmode: mode of ecc, see defines
+ * - chip_delay: chip dependent delay for transfering data from array to
+ *   read regs (tR)
+ * - options: various chip options. They can partly be set to inform
+ *   nand_scan about special functionality. See the defines for further
+ *   explanation
+ * Members with a "?" were not set in the merged testing-NAND branch,
+ * so they are not set here either.
+ */
+void board_nand_init(struct nand_chip *nand)
+{
+	unsigned long tCH, tCS, tWH, tWP, tRH, tRP, tRP_high, tR, tWHR, tAR;
+
+	/* set up GPIO Control Registers */
+	dfc_gpio_init();
+
+	/* turn on the NAND Controller Clock (104 MHz @ D0) */
+	CKENA |= (CKENA_4_NAND | CKENA_9_SMC);
+
+#undef CFG_TIMING_TIGHT
+#ifndef CFG_TIMING_TIGHT
+	tCH = MIN(((unsigned long) (NAND_TIMING_tCH * DFC_CLK_PER_US) + 1),
+		  DFC_MAX_tCH);
+	tCS = MIN(((unsigned long) (NAND_TIMING_tCS * DFC_CLK_PER_US) + 1),
+		  DFC_MAX_tCS);
+	tWH = MIN(((unsigned long) (NAND_TIMING_tWH * DFC_CLK_PER_US) + 1),
+		  DFC_MAX_tWH);
+	tWP = MIN(((unsigned long) (NAND_TIMING_tWP * DFC_CLK_PER_US) + 1),
+		  DFC_MAX_tWP);
+	tRH = MIN(((unsigned long) (NAND_TIMING_tRH * DFC_CLK_PER_US) + 1),
+		  DFC_MAX_tRH);
+	tRP = MIN(((unsigned long) (NAND_TIMING_tRP * DFC_CLK_PER_US) + 1),
+		  DFC_MAX_tRP);
+	tR = MIN(((unsigned long) (NAND_TIMING_tR * DFC_CLK_PER_US) + 1),
+		 DFC_MAX_tR);
+	tWHR = MIN(((unsigned long) (NAND_TIMING_tWHR * DFC_CLK_PER_US) + 1),
+		   DFC_MAX_tWHR);
+	tAR = MIN(((unsigned long) (NAND_TIMING_tAR * DFC_CLK_PER_US) + 1),
+		  DFC_MAX_tAR);
+#else /* this is the tight timing */
+
+	tCH = MIN(((unsigned long) (NAND_TIMING_tCH * DFC_CLK_PER_US)),
+		  DFC_MAX_tCH);
+	tCS = MIN(((unsigned long) (NAND_TIMING_tCS * DFC_CLK_PER_US)),
+		  DFC_MAX_tCS);
+	tWH = MIN(((unsigned long) (NAND_TIMING_tWH * DFC_CLK_PER_US)),
+		  DFC_MAX_tWH);
+	tWP = MIN(((unsigned long) (NAND_TIMING_tWP * DFC_CLK_PER_US)),
+		  DFC_MAX_tWP);
+	tRH = MIN(((unsigned long) (NAND_TIMING_tRH * DFC_CLK_PER_US)),
+		  DFC_MAX_tRH);
+	tRP = MIN(((unsigned long) (NAND_TIMING_tRP * DFC_CLK_PER_US)),
+		  DFC_MAX_tRP);
+	tR = MIN(((unsigned long) (NAND_TIMING_tR * DFC_CLK_PER_US) - tCH - 2),
+		 DFC_MAX_tR);
+	tWHR = MIN(((unsigned long) (NAND_TIMING_tWHR * DFC_CLK_PER_US) - tCH - 2),
+		   DFC_MAX_tWHR);
+	tAR = MIN(((unsigned long) (NAND_TIMING_tAR * DFC_CLK_PER_US) - 2),
+		  DFC_MAX_tAR);
+#endif /* CFG_TIMING_TIGHT */
+
+
+	DFC_DEBUG2("tCH=%u, tCS=%u, tWH=%u, tWP=%u, tRH=%u, tRP=%u, tR=%u, tWHR=%u, tAR=%u.\n", tCH, tCS, tWH, tWP, tRH, tRP, tR, tWHR, tAR);
+
+	/* tRP value is split in the register */
+	if(tRP & (1 << 4)) {
+		tRP_high = 1;
+		tRP &= ~(1 << 4);
+	} else {
+		tRP_high = 0;
+	}
+
+	NDTR0CS0 = (tCH << 19) |
+		(tCS << 16) |
+		(tWH << 11) |
+		(tWP << 8) |
+		(tRP_high << 6) |
+		(tRH << 3) |
+		(tRP << 0);
+
+	NDTR1CS0 = (tR << 16) |
+		(tWHR << 4) |
+		(tAR << 0);
+
+	/* If it doesn't work (unlikely) think about:
+	 *  - ecc enable
+	 *  - chip select don't care
+	 *  - read id byte count
+	 *
+	 * Intentionally enabled by not setting bits:
+	 *  - dma (DMA_EN)
+	 *  - page size = 512
+	 *  - cs don't care, see if we can enable later!
+	 *  - row address start position (after second cycle)
+	 *  - pages per block = 32
+	 *  - ND_RDY : clears command buffer
+	 */
+	/* NDCR_NCSX |		/\* Chip select busy don't care *\/ */
+
+	NDCR = (NDCR_SPARE_EN |		/* use the spare area */
+		NDCR_DWIDTH_C |		/* 16bit DFC data bus width  */
+		NDCR_DWIDTH_M |		/* 16 bit Flash device data bus width */
+		(2 << 16) |		/* read id count = 7 ???? mk@tbd */
+		NDCR_ND_ARB_EN |	/* enable bus arbiter */
+		NDCR_RDYM |		/* flash device ready ir masked */
+		NDCR_CS0_PAGEDM |	/* ND_nCSx page done ir masked */
+		NDCR_CS1_PAGEDM |
+		NDCR_CS0_CMDDM |	/* ND_CSx command done ir masked */
+		NDCR_CS1_CMDDM |
+		NDCR_CS0_BBDM |		/* ND_CSx bad block detect ir masked */
+		NDCR_CS1_BBDM |
+		NDCR_DBERRM |		/* double bit error ir masked */
+		NDCR_SBERRM |		/* single bit error ir masked */
+		NDCR_WRDREQM |		/* write data request ir masked */
+		NDCR_RDDREQM |		/* read data request ir masked */
+		NDCR_WRCMDREQM);	/* write command request ir masked */
+
+
+	/* wait 10 us due to cmd buffer clear reset */
+	/*	wait(10); */
+
+
+	nand->hwcontrol = dfc_hwcontrol;
+/*	nand->dev_ready = dfc_device_ready; */
+	nand->eccmode = NAND_ECC_SOFT;
+	nand->options = NAND_BUSWIDTH_16;
+	nand->waitfunc = dfc_wait;
+	nand->read_byte = dfc_read_byte;
+	nand->write_byte = dfc_write_byte;
+	nand->read_word = dfc_read_word;
+	nand->write_word = dfc_write_word;
+	nand->read_buf = dfc_read_buf;
+	nand->write_buf = dfc_write_buf;
+
+	nand->cmdfunc = dfc_cmdfunc;
+	nand->autooob = &delta_oob;
+	nand->badblock_pattern = &delta_bbt_descr;
+}
+
+#else
+ #error "U-Boot legacy NAND support not available for Monahans DFC."
+#endif
+#endif