path: root/drivers/mtd/devices/doc2001plus.c

/*
 * Linux driver for Disk-On-Chip Millennium Plus
 *
 * (c) 2002-2003 Greg Ungerer <gerg@snapgear.com>
 * (c) 2002-2003 SnapGear Inc
 * (c) 1999 Machine Vision Holdings, Inc.
 * (c) 1999, 2000 David Woodhouse <dwmw2@infradead.org>
 *
 * $Id: doc2001plus.c,v 1.14 2005/11/07 11:14:24 gleixner Exp $
 *
 * Released under GPL
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/errno.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/bitops.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/doc2000.h>

/* #define ECC_DEBUG */

/* I have no idea why some DoC chips can not use memcop_form|to_io().
 * This may be due to the different revisions of the ASIC controller built-in or
 * simplily a QA/Bug issue. Who knows ?? If you have trouble, please uncomment
 * this:*/
#undef USE_MEMCPY

static int doc_read(struct mtd_info *mtd, loff_t from, size_t len,
		size_t *retlen, u_char *buf);
static int doc_write(struct mtd_info *mtd, loff_t to, size_t len,
		size_t *retlen, const u_char *buf);
static int doc_read_oob(struct mtd_info *mtd, loff_t ofs,
			struct mtd_oob_ops *ops);
static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
			 struct mtd_oob_ops *ops);
static int doc_erase (struct mtd_info *mtd, struct erase_info *instr);

static struct mtd_info *docmilpluslist = NULL;


/* Perform the required delay cycles by writing to the NOP register */
static void DoC_Delay(void __iomem * docptr, int cycles)
{
	int i;

	for (i = 0; (i < cycles); i++)
		WriteDOC(0, docptr, Mplus_NOP);
}

#define	CDSN_CTRL_FR_B_MASK	(CDSN_CTRL_FR_B0 | CDSN_CTRL_FR_B1)

/* DOC_WaitReady: Wait for RDY line to be asserted by the flash chip */
static int _DoC_WaitReady(void __iomem * docptr)
{
	unsigned int c = 0xffff;

	DEBUG(MTD_DEBUG_LEVEL3,
	      "_DoC_WaitReady called for out-of-line wait\n");

	/* Out-of-line routine to wait for chip response */
	while (((ReadDOC(docptr, Mplus_FlashControl) & CDSN_CTRL_FR_B_MASK) != CDSN_CTRL_FR_B_MASK) && --c)
		;

	if (c == 0)
		DEBUG(MTD_DEBUG_LEVEL2, "_DoC_WaitReady timed out.\n");

	return (c == 0);
}

static inline int DoC_WaitReady(void __iomem * docptr)
{
	/* This is inline, to optimise the common case, where it's ready instantly */
	int ret = 0;

	/* read form NOP register should be issued prior to the read from CDSNControl
	   see Software Requirement 11.4 item 2. */
	DoC_Delay(docptr, 4);

	if ((ReadDOC(docptr, Mplus_FlashControl) & CDSN_CTRL_FR_B_MASK) != CDSN_CTRL_FR_B_MASK)
		/* Call the out-of-line routine to wait */
		ret = _DoC_WaitReady(docptr);

	return ret;
}

/* For some reason the Millennium Plus seems to occassionally put itself
 * into reset mode. For me this happens randomly, with no pattern that I
 * can detect. M-systems suggest always check this on any block level
 * operation and setting to normal mode if in reset mode.
 */
static inline void DoC_CheckASIC(void __iomem * docptr)
{
	/* Make sure the DoC is in normal mode */
	if ((ReadDOC(docptr, Mplus_DOCControl) & DOC_MODE_NORMAL) == 0) {
		WriteDOC((DOC_MODE_NORMAL | DOC_MODE_MDWREN), docptr, Mplus_DOCControl);
		WriteDOC(~(DOC_MODE_NORMAL | DOC_MODE_MDWREN), docptr, Mplus_CtrlConfirm);
	}
}

/* DoC_Command: Send a flash command to the flash chip through the Flash
 * command register. Need 2 Write Pipeline Terminates to complete send.
 */
static void DoC_Command(void __iomem * docptr, unsigned char command,
			       unsigned char xtraflags)
{
	WriteDOC(command, docptr, Mplus_FlashCmd);
	WriteDOC(command, docptr, Mplus_WritePipeTerm);
	WriteDOC(command, docptr, Mplus_WritePipeTerm);
}

/* DoC_Address: Set the current address for the flash chip through the Flash
 * Address register. Need 2 Write Pipeline Terminates to complete send.
 */
static inline void DoC_Address(struct DiskOnChip *doc, int numbytes,
			       unsigned long ofs, unsigned char